40001723D

PIC12(L)F1571/2
8-Pin MCU with High-Precision 16-Bit PWMs
Description:
PIC12(L)F1571/2 microcontrollers combine the capabilities of 16-bit PWMs with Analog to suit a variety of applications.
These devices deliver three 16-bit PWMs with independent timers for applications where high resolution is needed, such
as LED lighting, stepper motors, power supplies and other general purpose applications. The core independent
peripherals (16-bit PWMs, Complementary Waveform Generator), Enhanced Universal Synchronous Asynchronous
Receiver Transceiver (EUSART) and Analog (ADCs, Comparator and DAC) enable closed-loop feedback and
communication for use in multiple market segments. The EUSART peripheral enables the communication for
applications such as LIN.
Core Features:
eXtreme Low-Power (XLP) Features:
• C Compiler Optimized RISC Architecture
• Only 49 Instructions
• Operating Speed:
- DC – 32 MHz clock input
- 125 ns minimum instruction cycle
• Interrupt Capability
• 16-Level Deep Hardware Stack
• Two 8-Bit Timers
• One 16-Bit Timer
• Three Additional 16-Bit Timers available using the
16-Bit PWMs
• Power-on Reset (POR)
• Power-up Timer (PWRT)
• Low-Power Brown-out Reset (LPBOR)
• Programmable Watchdog Timer (WDT) up to 256s
• Programmable Code Protection
• Sleep mode: 20 nA @ 1.8V, Typical
• Watchdog Timer: 260 nA @ 1.8V, Typical
• Operating Current:
- 30 A/MHz @ 1.8V, typical
Memory:
•
•
•
•
Up to 3.5 Kbytes Flash Program Memory
Up to 256 Bytes Data SRAM Memory
Direct, Indirect and Relative Addressing modes
High-Endurance Flash Data Memory (HEF)
- 128 bytes if nonvolatile data storage
- 100k erase/write cycles
Operating Characteristics:
• Operating Voltage Range:
- 1.8V to 3.6V (PIC12LF1571/2)
- 2.3V to 5.5V (PIC12F1571/2)
• Temperature Range:
- Industrial: -40°C to +85°C
- Extended: -40°C to +125°C
• Internal Voltage Reference module
• In-Circuit Serial Programming™ (ICSP™) via
Two Pins
 2013-2015 Microchip Technology Inc.
Digital Peripherals:
• 16-Bit PWM:
- Three 16-bit PWMs with independent timers
- Multiple Output modes (Edge-Aligned,
Center-Aligned, Set and Toggle on
Register Match)
- User settings for phase, duty cycle, period,
offset and polarity
- 16-bit timer capability
- Interrupts generated based on timer matches
with Offset, Duty Cycle, Period and Phase
registers
• Complementary Waveform Generator (CWG):
- Rising and falling edge dead-band control
- Multiple signal sources
• Enhanced Universal Synchronous Asynchronous
Receiver Transceiver (EUSART):
- Supports LIN applications
Device I/O Port Features:
• Six I/Os
• Individually Selectable Weak Pull-ups
• Interrupt-On-Change Pins Option with
Edge-Selectable Option
DS40001723D-page 1
PIC12(L)F1571/2
Analog Peripherals:
Clocking Structure:
• 10-Bit Analog-to-Digital Converter (ADC):
- Up to four external channels
- Conversion available during Sleep
• Comparator:
- Low-Power/High-Speed modes
- Fixed Voltage Reference at (non)inverting
input(s)
- Comparator outputs externally accessible
- Synchronization with Timer1 clock source
- Software hysteresis enable
• 5-Bit Digital-to-Analog Converter (DAC):
- 5-bit resolution, rail-to-rail
- Positive reference selection
- Unbuffered I/O pin output
- Internal connections to ADCs and
comparators
• Voltage Reference:
- Fixed voltage reference with 1.024V, 2.048V
and 4.096V output levels
• Precision Internal Oscillator:
- Factory calibrated ±1%, typical
- Software-selectable clock speeds from
31 kHz to 32 MHz
• External Oscillator Block with:
- Resonator modes up to 20 MHz
- Two External Clock modes up to 32 MHz
• Fail-Safe Clock Monitor
• Digital Oscillator Input Available
Data Sheet Index
Program Memory Flash
(K words)
Data SRAM (bytes)
High-Endurance
Flash (bytes)
I/O Pins
8-Bit/16-Bit Timers
Comparators
16-Bit PWM
10-Bit ADC (ch)
5-Bit DAC
CWG
EUSART
Debug(1)
XLP
PIC12(L)F1571/2 FAMILY TYPES
PIC12(L)F1571
A
1
128
128
6
2/4(2)
1
3
4
1
1
0
I
Y
PIC12(L)F1572
A
2
256
128
6
2/4(2)
1
3
4
1
1
1
I
Y
Device
Note 1:
2:
I – Debugging integrated on chip.
Three additional 16-bit timers available when not using the 16-bit PWM outputs.
Data Sheet Index: (Unshaded devices are described in this document.)
A
DS40001723
DS40001723D-page 2
PIC12(L)F1571/2 Data Sheet, 8-Pin Flash, 8-Bit MCU with High-Precision 16-Bit PWM.
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
PIN DIAGRAMS
1
RA5
2
RA4
3
RA3/MCLR/VPP
4
PIC12(L)F1572
VDD
PIC12(L)F1571
Pin Diagram – 8-Pin PDIP, SOIC, DFN, MSOP, UDFN
8
VSS
7
RA0/ICSPDAT
6
RA1/ICSPCLK
5
RA2
Note: See Table 1 for location of all peripheral functions.
8-Pin PDIP/SOIC/MSOP/DFN/UDFN
ADC
Reference
Comparator
Timers
PWM
EUSART(2)
CWG
Interrupt
Pull-up
Basic
8-PIN ALLOCATION TABLE (PIC12(L)F1571/2)
I/O
TABLE 1:
RA0
7
AN0
DAC1OUT
C1IN+
—
PWM2
TX(2)
CK(2)
CWG1B
IOC
Y
ICSPDAT
ICDDAT
RA1
6
AN1
VREF+
C1IN0-
—
PWM1
RX(2)
DT(2)
—
IOC
Y
ICSPCLK
ICDCLK
RA2
5
AN2
—
C1OUT
T0CKI
PWM3
—
CWG1FLT
CWG1A
IOC
INT
Y
—
RA3
4
—
—
—
T1G(1)
—
—
—
IOC
Y
MCLR
VPP
RA4
3
AN3
—
C1IN1-
T1G
PWM2(1)
TX(1,2)
CK(1,2)
CWG1B(1)
IOC
Y
CLKOUT
RA5
2
—
—
—
T1CKI
PWM1(1)
RX(1,2)
DT(1,2)
CWG1A(1)
IOC
Y
CLKIN
VDD
1
—
—
—
—
—
—
—
—
—
VDD
Vss
8
—
—
—
—
—
—
—
—
—
VSS
Note 1:
2:
Alternate pin function selected with the APFCON (Register 11-1) register.
PIC12(L)F1572 only.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 3
PIC12(L)F1571/2
Table of Contents
1.0 Device Overview .......................................................................................................................................................................... 7
2.0 Enhanced Mid-Range CPU ........................................................................................................................................................ 13
3.0 Memory Organization ................................................................................................................................................................. 15
4.0 Device Configuration .................................................................................................................................................................. 41
5.0 Oscillator Module........................................................................................................................................................................ 47
6.0 Resets ........................................................................................................................................................................................ 59
7.0 Interrupts .................................................................................................................................................................................... 69
8.0 Power-Down Mode (Sleep) ........................................................................................................................................................ 83
9.0 Watchdog Timer (WDT) ............................................................................................................................................................. 87
10.0 Flash Program Memory Control ................................................................................................................................................. 91
11.0 I/O Ports ................................................................................................................................................................................... 109
12.0 Interrupt-On-Change ................................................................................................................................................................ 119
13.0 Fixed Voltage Reference (FVR) ............................................................................................................................................... 123
14.0 Temperature Indicator Module ................................................................................................................................................. 127
15.0 Analog-to-Digital Converter (ADC) Module .............................................................................................................................. 129
16.0 5-Bit Digital-to-Analog Converter (DAC) Module ...................................................................................................................... 143
17.0 Comparator Module.................................................................................................................................................................. 147
18.0 Timer0 Module ......................................................................................................................................................................... 155
19.0 Timer1 Module with Gate Control............................................................................................................................................. 159
20.0 Timer2 Module ......................................................................................................................................................................... 171
21.0 Enhanced Universal Synchronous Asynchronous Receiver Transmitter (EUSART) ............................................................... 175
22.0 16-Bit Pulse-Width Modulation (PWM) Module ........................................................................................................................ 203
23.0 Complementary Waveform Generator (CWG) Module ............................................................................................................ 231
24.0 In-Circuit Serial Programming™ (ICSP™) ............................................................................................................................... 243
25.0 Instruction Set Summary .......................................................................................................................................................... 245
26.0 Electrical Specifications............................................................................................................................................................ 259
27.0 DC and AC Characteristics Graphs and Charts ....................................................................................................................... 283
28.0 Development Support............................................................................................................................................................... 305
29.0 Packaging Information.............................................................................................................................................................. 309
Appendix A: Data Sheet Revision History.......................................................................................................................................... 327
The Microchip Web Site ..................................................................................................................................................................... 329
Customer Change Notification Service .............................................................................................................................................. 329
Customer Support .............................................................................................................................................................................. 329
Product Identification System............................................................................................................................................................. 331
DS40001723D-page 4
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
TO OUR VALUED CUSTOMERS
It is our intention to provide our valued customers with the best documentation possible to ensure successful use of your Microchip
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If you have any questions or comments regarding this publication, please contact the Marketing Communications Department via
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Most Current Data Sheet
To obtain the most up-to-date version of this data sheet, please register at our Worldwide Web site at:
http://www.microchip.com
You can determine the version of a data sheet by examining its literature number found on the bottom outside corner of any page.
The last character of the literature number is the version number, (e.g., DS30000000A is version A of document DS30000000).
Errata
An errata sheet, describing minor operational differences from the data sheet and recommended workarounds, may exist for current
devices. As device/documentation issues become known to us, we will publish an errata sheet. The errata will specify the revision
of silicon and revision of document to which it applies.
To determine if an errata sheet exists for a particular device, please check with one of the following:
• Microchip’s Worldwide Web site; http://www.microchip.com
• Your local Microchip sales office (see last page)
When contacting a sales office, please specify which device, revision of silicon and data sheet (include literature number) you are
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Register on our web site at www.microchip.com to receive the most current information on all of our products.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 5
PIC12(L)F1571/2
NOTES:
DS40001723D-page 6
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
1.0
DEVICE OVERVIEW
1.1
The PIC12(L)F1571/2 devices are described within this
data sheet. The block diagram of these devices is shown
in Figure 1-1, the available peripherals are shown in
Table 1-1 and the pinout descriptions are shown in
Table 1-2.
Peripheral
PIC12(L)F1572
DEVICE PERIPHERAL
SUMMARY
PIC12(L)F1571
TABLE 1-1:
Analog-to-Digital Converter (ADC)
●
●
Complementary Wave Generator
(CWG)
●
●
Digital-to-Analog Converter (DAC)
●
●
Enhanced Universal
Synchronous/Asynchronous
Receiver/Transmitter (EUSART)
REGISTER NAMES
When there are multiple instances of the same
peripheral in a device, the peripheral control registers
will be depicted as the concatenation of a peripheral
identifier, peripheral instance and control identifier. The
control registers section will show just one instance of
all the register names with an ‘x’ in the place of the
peripheral instance number. This naming convention
may also be applied to peripherals when there is only
one instance of that peripheral in the device to maintain
compatibility with other devices in the family that
contain more than one.
1.1.2
BIT NAMES
There are two variants for bit names:
• Short name: Bit function abbreviation
• Long name: Peripheral abbreviation + short name
●
1.1.2.1
Short bit names are an abbreviation for the bit function.
For example, some peripherals are enabled with the
EN bit. The bit names shown in the registers are the
short name variant.
Fixed Voltage Reference (FVR)
●
●
Temperature Indicator
●
●
C1
●
●
PWM1
●
●
PWM2
●
●
PWM3
●
●
Timer0
●
●
Timer1
●
●
Timer2
●
●
Comparators
PWM Modules
Timers
 2013-2015 Microchip Technology Inc.
1.1.1
Register and Bit Naming
Conventions
Short Bit Names
Short bit names are useful when accessing bits in C
programs. The general format for accessing bits by the
short name is RegisterNamebits.ShortName. For
example, the enable bit, EN, in the COG1CON0 register can be set in C programs with the instruction,
COG1CON0bits.EN = 1.
Short names are generally not useful in assembly
programs because the same name may be used by
different peripherals in different bit positions. When this
occurs, during the include file generation, all instances
of that short bit name are appended with an
underscore, plus the name of the register in which the
bit resides, to avoid naming contentions.
DS40001723D-page 7
PIC12(L)F1571/2
1.1.2.2
Long Bit Names
Long bit names are constructed by adding a peripheral
abbreviation prefix to the short name. The prefix is
unique to the peripheral, thereby making every long bit
name unique. The long bit name for the COG1 enable bit
is the COG1 prefix, G1, appended with the enable bit
short name, EN, resulting in the unique bit name G1EN.
Long bit names are useful in both C and assembly programs. For example, in C, the COG1CON0 enable bit
can be set with the G1EN = 1 instruction. In assembly,
this bit can be set with the BSF COG1CON0,G1EN
instruction.
1.1.2.3
Bit Fields
Bit fields are two or more adjacent bits in the same
register. Bit fields adhere only to the short bit naming
convention. For example, the three Least Significant
bits of the COG1CON0 register contain the mode
control bits. The short name for this field is MD. There
is no long bit name variant. Bit field access is only
possible in C programs. The following example
demonstrates a C program instruction for setting the
COG1 to the Push-Pull mode:
1.1.3
1.1.3.1
REGISTER AND BIT NAMING
EXCEPTIONS
Status, Interrupt and Mirror Bits
Status, interrupt enables, interrupt flags and mirror bits
are contained in registers that span more than one
peripheral. In these cases, the bit name shown is
unique so there is no prefix or short name variant.
1.1.3.2
Legacy Peripherals
There are some peripherals that do not strictly adhere
to these naming conventions. Peripherals that have
existed for many years and are present in almost every
device are the exceptions. These exceptions were
necessary to limit the adverse impact of the new
conventions on legacy code. Peripherals that do
adhere to the new convention will include a table in the
registers section indicating the long name prefix for
each peripheral instance. Peripherals that fall into the
exception category will not have this table. These
peripherals include, but are not limited to, the following:
• EUSART
• MSSP
COG1CON0bits.MD = 0x5;
Individual bits in a bit field can also be accessed with
long and short bit names. Each bit is the field name
appended with the number of the bit position within the
field. For example, the Most Significant mode bit has
the short bit name, MD2, and the long bit name is
G1MD2. The following two examples demonstrate
assembly program sequences for setting the COG1 to
Push-Pull mode:
Example 1:
MOVLW
ANDWF
MOVLW
IORWF
~(1<<G1MD1)
COG1CON0,F
1<<G1MD2 | 1<<G1MD0
COG1CON0,F
Example 2:
BSF
BCF
BSF
COG1CON0,G1MD2
COG1CON0,G1MD1
COG1CON0,G1MD0
DS40001723D-page 8
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
FIGURE 1-1:
PIC12(L)F1571/2 BLOCK DIAGRAM
Rev. 10-000039E
9/12/2013
Program
Flash Memory
RAM
PORTA
CLKOUT
Timing
Generation
CPU
CLKIN
INTRC
Oscillator
(Note 3)
MCLR
TMR2
TMR1
CWG1
Note 1:
2:
3:
4:
TMR0
C1
Temp
Indicator
ADC
10-bit
PWM3
DAC
PWM2
FVR
PWM1
EUSART(4)
See applicable chapters for more information on peripherals.
See Table 1-1 for peripherals available on specific devices.
See Figure 2-1.
PIC12(L)F1572 only.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 9
PIC12(L)F1571/2
TABLE 1-2:
PIC12(L)F1571/2 PINOUT DESCRIPTION
Name
RA0/AN0/C1IN+/DACOUT/
TX(2)/CK(2)/CWG1B/PWM2/
ICSPDAT/ICDDAT
Function
Input
Type
Output
Type
RA0
General purpose I/O.
AN0
ADC channel input.
C1IN+
Comparator positive input.
DACOUT
TX
Digital-to-Analog Converter output.
(3)
(4)
CK
CWG complementary output.
PWM2
PWM output.
ICSPDAT
ICSP™ data I/O.
ICDDAT
In-circuit debug data.
RA1
General purpose I/O.
AN1
ADC channel input.
VREF+
ADC Voltage Reference input.
C1IN0RX
Comparator negative input.
(3)
(4)
DT
PWM output.
ICSPCLK
ICSP programming clock.
ICDCLK
In-circuit debug clock.
RA2
General purpose I/O.
AN2
ADC channel input.
C1OUT
Comparator output.
T0CKI
(3)
(4)
CWG1FLT
CWG complementary output.
PWM3
PWM output.
INT
External interrupt.
RA3
General purpose input with IOC and WPU.
VPP
(3)
(4)
T1G
Programming voltage.
Timer1 gate input.
Master Clear with internal pull-up.
MCLR
RA4/AN3/C1IN1-/T1G/TX(1,2)/
CK(1,2)/CWG1B(1)/PWM2(1)/
CLKOUT
Timer0 clock input.
Complementary Waveform Generator Fault input.
CWG1A
RA3/VPP/T1G(1)/MCLR
USART asynchronous input.
USART synchronous data.
PWM1
RA2/AN2/C1OUT/T0CKI/
CWG1FLT/CWG1A/PWM3/INT
USART asynchronous transmit.
USART synchronous clock.
CWG1B
RA1/AN1/VREF+/C1IN0-/RX(2)/
DT(2)/PWM1/ICSPCLK/ICDCLK
Description
RA4
General purpose I/O.
AN3
ADC channel input.
C1IN1-
Comparator negative input.
T1G
TX
CK
CWG1B
PWM2
CLKOUT
Timer1 gate input.
(3)
(4)
USART asynchronous transmit.
USART synchronous clock.
CWG complementary output.
PWM output.
FOSC/4 output.
Legend: AN = Analog input or output CMOS = CMOS compatible input or output
TTL = TTL compatible input ST
= Schmitt Trigger input with CMOS levels
HV = High Voltage
XTAL = Crystal
Note 1: Alternate pin function selected with the APFCON (Register 11-1) register.
2: PIC12(L)F1572 only.
3: Input type is selected by the port.
4: Output type is selected by the port.
DS40001723D-page 10
OD = Open-Drain
I2C = Schmitt Trigger input with I2C
levels
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
TABLE 1-2:
PIC12(L)F1571/2 PINOUT DESCRIPTION (CONTINUED)
Name
RA5/T1CKI/RX(1,2)/DT(1,2)/
CWG1A(1)/PWM1(1)/CLKIN
Function
Input
Type
Output
Type
General purpose I/O.
RA5
T1CKI
Timer1 clock input.
RX
DT
Description
USART asynchronous input.
(3)
(4)
CWG1A
USART synchronous data.
CWG complementary output.
PWM1
PWM output.
CLKIN
External Clock input (EC mode).
VDD
VDD
Power
—
Positive supply.
VSS
VSS
Power
—
Ground reference.
Legend: AN = Analog input or output CMOS = CMOS compatible input or output
TTL = TTL compatible input ST
= Schmitt Trigger input with CMOS levels
HV = High Voltage
XTAL = Crystal
Note 1: Alternate pin function selected with the APFCON (Register 11-1) register.
2: PIC12(L)F1572 only.
3: Input type is selected by the port.
4: Output type is selected by the port.
 2013-2015 Microchip Technology Inc.
OD = Open-Drain
I2C = Schmitt Trigger input with I2C
levels
DS40001723D-page 11
PIC12(L)F1571/2
NOTES:
DS40001723D-page 12
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
2.0
ENHANCED MID-RANGE CPU
•
•
•
•
This family of devices contains an enhanced mid-range
8-bit CPU core. The CPU has 49 instructions. Interrupt
capability includes automatic context saving. The
hardware stack is 16 levels deep and has Overflow and
Underflow Reset capability. Direct, Indirect and
Relative Addressing modes are available. Two File
Select Registers (FSRs) provide the ability to read
program and data memory.
FIGURE 2-1:
Automatic Interrupt Context Saving
16-Level Stack with Overflow and Underflow
File Select Registers
Instruction Set
CORE BLOCK DIAGRAM
Rev. 10-000055A
7/30/2013
15
Configuration
15
MUX
Flash
Program
Memory
Data Bus
16-Level Stack
(15-bit)
RAM
14
Program
Bus
8
Program Counter
12
Program Memory
Read (PMR)
RAM Addr
Addr MUX
Instruction Reg
Direct Addr
7
5
Indirect
Addr
12
12
BSR Reg
15
FSR0 Reg
15
FSR1 Reg
STATUS Reg
8
Instruction
Decode and
Control
CLKIN
CLKOUT
Timing
Generation
Internal
Oscillator
Block
 2013-2015 Microchip Technology Inc.
Power-up
Timer
Power-on
Reset
Watchdog
Timer
Brown-out
Reset
VDD
3
8
MUX
ALU
W Reg
VSS
DS40001723D-page 13
PIC12(L)F1571/2
2.1
Automatic Interrupt Context
Saving
During interrupts, certain registers are automatically
saved in shadow registers and restored when returning
from the interrupt. This saves stack space and user
code. See Section 7.5 “Automatic Context Saving”,
for more information.
2.2
16-Level Stack with Overflow and
Underflow
These devices have a hardware stack memory, 15 bits
wide and 16 words deep. A Stack Overflow or Underflow
will set the appropriate bit (STKOVF or STKUNF) in the
PCON register, and if enabled, will cause a Software
Reset. See Section 3.5 “Stack” for more details.
DS40001723D-page 14
2.3
File Select Registers
There are two 16-bit File Select Registers (FSR). FSRs
can access all file registers and program memory,
which allows one Data Pointer for all memory. When an
FSR points to program memory, there is one additional
instruction cycle in instructions using INDF to allow the
data to be fetched. General purpose memory can now
also be addressed linearly, providing the ability to
access contiguous data larger than 80 bytes. There
are also new instructions to support the FSRs. See
Section 3.6 “Indirect Addressing” for more details.
2.4
Instruction Set
There are 49 instructions for the enhanced midrange CPU to support the features of the CPU. See
Section 25.0 “Instruction Set Summary” for more
details.
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
3.0
MEMORY ORGANIZATION
These devices contain the following types of memory:
• Program Memory:
- Configuration Words
- Device ID
- User ID
- Flash Program Memory
• Data Memory:
- Core Registers
- Special Function Registers
- General Purpose RAM
- Common RAM
• PCL and PCLATH
• Stack
• Indirect Addressing
Program Memory Organization
The enhanced mid-range core has a 15-bit Program
Counter (PC) capable of addressing a 32K x 14 program
memory space. Table 3-1 shows the memory sizes
implemented. Accessing a location above these boundaries will cause a wraparound within the implemented
memory space. The Reset vector is at 0000h and the
interrupt vector is at 0004h (see Figure 3-1).
3.2
The following features are associated with access and
control of program memory and data memory:
TABLE 3-1:
3.1
High-Endurance Flash
This device has a 128-byte section of high-endurance
Program Flash Memory (PFM) in lieu of data
EEPROM. This area is especially well-suited for nonvolatile data storage that is expected to be updated
frequently over the life of the end product. See
Section 10.2 “Flash Program Memory Overview”
for more information on writing data to PFM. See
Section 3.2.1.2 “Indirect Read with FSR” for more
information about using the FSR registers to read byte
data stored in PFM.
DEVICE SIZES AND ADDRESSES
Program Memory
Space (Words)
Last Program Memory
Address
High-Endurance Flash
Memory Address Range(1)
PIC12(L)F1571
1,024
03FFh
0380h-03FFh
PIC12(L)F1572
2,048
07FFh
0780h-07FFh
Device
Note 1:
High-endurance Flash applies to the low byte of each address in the range.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 15
PIC12(L)F1571/2
FIGURE 3-1:
PROGRAM MEMORY MAP
AND STACK FOR
PIC12(L)F1571
FIGURE 3-2:
PROGRAM MEMORY MAP
AND STACK FOR
PIC12(L)F1572
Rev. 10-000040C
7/30/2013
Rev. 10-000040D
7/30/2013
PC<14:0>
CALL, CALLW
RETURN, RETLW
Interrupt, RETFIE
PC<14:0>
15
CALL, CALLW
RETURN, RETLW
Interrupt, RETFIE
Stack Level 0
Stack Level 0
Stack Level 1
Stack Level 1
Stack Level 15
On-chip
Program
Memory
Stack Level 15
Reset Vector
0000h
Interrupt Vector
0004h
0005h
Page 0
Rollover to Page 0
03FFh
0400h
Rollover to Page 0
7FFFh
DS40001723D-page 16
15
On-chip
Program
Memory
Reset Vector
0000h
Interrupt Vector
0004h
0005h
Page 0
Rollover to Page 0
07FFh
0800h
Rollover to Page 0
7FFFh
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
3.2.1
READING PROGRAM MEMORY AS
DATA
3.2.1.2
Indirect Read with FSR
The RETLW instruction can be used to provide access
to tables of constants. The recommended way to create
such a table is shown in Example 3-1.
The program memory can be accessed as data by
setting bit 7 of the FSRnH register and reading the
matching INDFn register. The MOVIW instruction will
place the lower eight bits of the addressed word in the
W register. Writes to the program memory cannot be
performed via the INDFn registers. Instructions that
access the program memory via the FSR require one
extra instruction cycle to complete. Example 3-2
demonstrates accessing the program memory via an
FSR.
EXAMPLE 3-1:
The HIGH operator will set bit<7> if a label points to a
location in program memory.
There are two methods of accessing constants in program memory. The first method is to use tables of
RETLW instructions. The second method is to set an
FSR to point to the program memory.
3.2.1.1
RETLW Instruction
constants
BRW
RETLW
RETLW
RETLW
RETLW
DATA0
DATA1
DATA2
DATA3
RETLW INSTRUCTION
;Add Index in W to
;program counter to
;select data
;Index0 data
;Index1 data
my_function
;… LOTS OF CODE…
MOVLW
DATA_INDEX
call constants
;… THE CONSTANT IS IN W
The BRW instruction makes this type of table very
simple to implement. If your code must remain portable
with previous generations of microcontrollers, then the
BRW instruction is not available, so the older table read
method must be used.
 2013-2015 Microchip Technology Inc.
EXAMPLE 3-2:
ACCESSING PROGRAM
MEMORY VIA FSR
constants
DW
DATA0
;First constant
DW
DATA1
;Second constant
DW
DATA2
DW
DATA3
my_function
;… LOTS OF CODE…
MOVLW DATA_INDEX
ADDLW LOW constants
MOVWF FSR1L
MOVLW HIGH constants ;MSb is set
automatically
MOVWF FSR1H
BTFSC STATUS,C
;carry from ADDLW?
INCF
FSR1H,f
;yes
MOVIW 0[FSR1]
;THE PROGRAM MEMORY IS IN W
DS40001723D-page 17
PIC12(L)F1571/2
3.3
Data Memory Organization
The data memory is partitioned in 32 memory banks
with 128 bytes in a bank. Each bank consists of
(Figure 3-3):
•
•
•
•
12 Core Registers
20 Special Function Registers (SFR)
Up to 80 bytes of General Purpose RAM (GPR)
16 bytes of Common RAM
The active bank is selected by writing the bank number
into the Bank Select Register (BSR). Unimplemented
memory will read as ‘0’. All data memory can be
accessed either directly (via instructions that use the file
registers) or indirectly via the two File Select Registers
(FSR). See Section 3.6 “Indirect Addressing” for
more information.
Data memory uses a 12-bit address. The upper five bits
of the address define the bank address and the lower
seven bits select the registers/RAM in that bank.
DS40001723D-page 18
3.3.1
CORE REGISTERS
The core registers contain the registers that directly
affect the basic operation. The core registers occupy
the first 12 addresses of every data memory bank
(addresses: x00h/x08h through x0Bh/x8Bh). These
registers are listed below in Table 3-2. For detailed
information, see Table 3-9.
TABLE 3-2:
CORE REGISTERS
Addresses
BANKx
x00h or x80h
x01h or x81h
x02h or x82h
x03h or x83h
x04h or x84h
x05h or x85h
x06h or x86h
x07h or x87h
x08h or x88h
x09h or x89h
x0Ah or x8Ah
x0Bh or x8Bh
INDF0
INDF1
PCL
STATUS
FSR0L
FSR0H
FSR1L
FSR1H
BSR
WREG
PCLATH
INTCON
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
3.3.1.1
STATUS Register
The STATUS register, shown in Register 3-1, contains:
• The arithmetic status of the ALU
• The Reset status
The STATUS register can be the destination for any
instruction, like any other register. If the STATUS
register is the destination for an instruction that affects
the Z, DC or C bits, then the write to these three bits is
disabled. These bits are set or cleared according to the
device logic. Furthermore, the TO and PD bits are not
writable. Therefore, the result of an instruction with the
STATUS register as destination may be different than
intended.
REGISTER 3-1:
For example, CLRF STATUS will clear the upper three
bits and set the Z bit. This leaves the STATUS register
as ‘000u u1uu’ (where u = unchanged).
It is recommended, therefore, that only BCF, BSF,
SWAPF and MOVWF instructions are used to alter the
STATUS register, because these instructions do not
affect any Status bits. For other instructions not affecting
any Status bits, refer to Section 25.0 “Instruction Set
Summary”).
Note 1: The C and DC bits operate as Borrow
and Digit Borrow out bits, respectively, in
subtraction.
STATUS: STATUS REGISTER
U-0
U-0
U-0
R-1/q
R-1/q
R/W-0/u
R/W-0/u
R/W-0/u
—
—
—
TO
PD
Z
DC(1)
C(1)
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
q = Value depends on condition
bit 7-5
Unimplemented: Read as ‘0’
bit 4
TO: Time-out bit
1 = After power-up, CLRWDT instruction or SLEEP instruction
0 = A WDT time-out occurred
bit 3
PD: Power-Down bit
1 = After power-down or by the CLRWDT instruction
0 = By execution of the SLEEP instruction
bit 2
Z: Zero bit
1 = The result of an arithmetic or logic operation is zero
0 = The result of an arithmetic or logic operation is not zero
bit 1
DC: Digit Carry/Digit Borrow bit (ADDWF, ADDLW, SUBLW, SUBWF instructions)(1)
1 = A carry-out from the 4th low-order bit of the result occurred
0 = No carry-out from the 4th low-order bit of the result
bit 0
C: Carry/Borrow bit(1) (ADDWF, ADDLW, SUBLW, SUBWF instructions)(1)
1 = A carry-out from the Most Significant bit of the result occurred
0 = No carry-out from the Most Significant bit of the result occurred
Note 1:
For Borrow, the polarity is reversed. A subtraction is executed by adding the two’s complement of the
second operand. For rotate (RRF, RLF) instructions, this bit is loaded with either the high-order or low-order
bit of the source register.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 19
PIC12(L)F1571/2
3.3.2
SPECIAL FUNCTION REGISTER
The Special Function Registers are registers used by
the application to control the desired operation of
peripheral functions in the device. The Special Function
Registers occupy the 20 bytes after the core registers of
every data memory bank (addresses: x0Ch/x8Ch
through x1Fh/x9Fh). The registers associated with the
operation of the peripherals are described in the
appropriate peripheral chapter of this data sheet.
3.3.3
GENERAL PURPOSE RAM
There are up to 80 bytes of GPR in each data memory
bank. The Special Function Registers occupy the
20 bytes after the core registers of every data memory
bank (addresses: x0Ch/x8Ch through x1Fh/x9Fh).
3.3.3.1
FIGURE 3-3:
BANKED MEMORY
PARTITIONING
Rev. 10-000041A
7/30/2013
7-bit Bank Offset
00h
Core Registers
(12 bytes)
0Bh
0Ch
Special Function Registers
(20 bytes maximum)
1Fh
20h
Linear Access to GPR
The general purpose RAM can be accessed in
a non-banked method via the FSRs. This can
simplify access to large memory structures. See
Section 3.6.2 “Linear Data Memory” for more
information.
3.3.4
Memory Region
General Purpose RAM
(80 bytes maximum)
COMMON RAM
There are 16 bytes of common RAM accessible from all
banks.
3.3.5
DEVICE MEMORY MAPS
The memory maps for PIC12(L)F1571/2 are as shown
in Table 3-3 through Table 3-8.
6Fh
70h
Common RAM
(16 bytes)
7Fh
DS40001723D-page 20
 2013-2015 Microchip Technology Inc.
 2013-2015 Microchip Technology Inc.
TABLE 3-3:
PIC12(L)F1571 MEMORY MAP, BANK 0-7
BANK 0
000h
BANK 1
080h
Core Registers
(Table 3-2)
00Bh
BANK 2
100h
Core Registers
(Table 3-2)
08Bh
BANK 3
180h
Core Registers
(Table 3-2)
10Bh
BANK 4
200h
Core Registers
(Table 3-2)
18Bh
BANK 5
280h
Core Registers
(Table 3-2)
20Bh
BANK 6
300h
Core Registers
(Table 3-2)
28Bh
BANK 7
380h
Core Registers
(Table 3-2)
30Bh
Core Registers
(Table 3-2)
38Bh
00Ch
PORTA
08Ch
TRISA
10Ch
LATA
18Ch
ANSELA
20Ch
WPUA
28Ch
ODCONA
30Ch
SLRCONA
38Ch
INLVLA
00Dh
—
08Dh
—
10Dh
—
18Dh
—
20Dh
—
28Dh
—
30Dh
—
38Dh
—
00Eh
—
08Eh
—
10Eh
—
18Eh
—
20Eh
—
28Eh
—
30Eh
—
38Eh
—
00Fh
—
08Fh
—
10Fh
—
18Fh
—
20Fh
—
28Fh
—
30Fh
—
38Fh
—
010h
—
090h
—
110h
—
190h
—
210h
—
290h
—
310h
—
390h
—
011h
PIR1
091h
PIE1
111h
CM1CON0
191h
PMADRL
211h
—
291h
—
311h
—
391h
IOCAP
012h
PIR2
092h
PIE2
112h
CM1CON1
192h
PMADRH
212h
—
292h
—
312h
—
392h
IOCAN
013h
PIR3
093h
PIE3
113h
—
193h
PMDATL
213h
—
293h
—
313h
—
393h
IOCAF
014h
—
094h
—
114h
—
194h
PMDATH
214h
—
294h
—
314h
—
394h
—
015h
TMR0
095h
OPTION_REG
115h
CMOUT
195h
PMCON1
215h
—
295h
—
315h
—
395h
—
016h
TMR1L
096h
PCON
116h
BORCON
196h
PMCON2
216h
—
296h
—
316h
—
396h
—
017h
TMR1H
097h
WDTCON
117h
FVRCON
197h
VREGCON(1)
217h
—
297h
—
317h
—
397h
—
018h
T1CON
098h
OSCTUN E
118h
DACxCON0
198h
—
218h
—
298h
—
318h
—
398h
—
019h
T1GCON
099h
OSCCON
119h
DACxCON1
199h
—
219h
—
299h
—
319h
—
399h
—
01Ah
TMR2
09Ah
OSCSTAT
11Ah
—
19Ah
—
21Ah
—
29Ah
—
31Ah
—
39Ah
—
01Bh
PR2
09Bh
ADRESL
11Bh
—
19Bh
—
21Bh
—
29Bh
—
31Bh
—
39Bh
—
01Ch
T2CON
09Ch
ADRESH
11Ch
—
19Ch
—
21Ch
—
29Ch
—
31Ch
—
39Ch
—
01Dh
—
09Dh
ADCON0
11Dh
APFCON
19Dh
—
21Dh
—
29Dh
—
31Dh
—
39Dh
—
01Eh
—
09Eh
ADCON1
11Eh
—
19Eh
—
21Eh
—
29Eh
—
31Eh
—
39Eh
—
01Fh
—
09Fh
ADCON2
11Fh
—
19Fh
—
21Fh
—
29Fh
—
31Fh
—
39Fh
—
020h
0C0h
06Fh
0EFh
070h
0F0h
Common RAM
DS40001723D-page 21
07Fh
0FFh
Unimplemented
Read as ‘0’
Common RAM
(Accesses
70h-7Fh)
120h
1A0h
Unimplemented
Read as ‘0’
16Fh
170h
17Fh
220h
Unimplemented
Read as ‘0’
1EFh
1F0h
Common RAM
(Accesses
70h-7Fh)
Legend:
= Unimplemented data memory locations, read as ‘0’.
Note 1: PIC12F1571 only.
1FFh
2A0h
Unimplemented
Read as ‘0’
26Fh
270h
Common RAM
(Accesses
70h-7Fh)
27Fh
320h
Unimplemented
Read as ‘0’
2FFh
Unimplemented
Read as ‘0’
36Fh
2EFh
2F0h
Common RAM
(Accesses
70h-7Fh)
3A0h
3EFh
370h
Common RAM
(Accesses
70h-7Fh)
37Fh
Unimplemented
Read as ‘0’
3F0h
Common RAM
(Accesses
70h-7Fh)
3FFh
Common RAM
(Accesses
70h-7Fh)
PIC12(L)F1571/2
General
Purpose
Register
80 Bytes
0A0h General Purpose
Register
48 Bytes
0BFh
PIC12(L)F1572 MEMORY MAP, BANK 0-7
BANK 0
000h
BANK 1
080h
Core Registers
(Table 3-2)
00Bh
BANK 2
100h
Core Registers
(Table 3-2)
08Bh
BANK 3
180h
Core Registers
(Table 3-2)
10Bh
BANK 4
200h
Core Registers
(Table 3-2)
18Bh
BANK 5
280h
Core Registers
(Table 3-2)
20Bh
BANK 6
300h
Core Registers
(Table 3-2)
28Bh
BANK 7
380h
Core Registers
(Table 3-2)
30Bh
Core Registers
(Table 3-2)
38Bh
00Ch
PORTA
08Ch
TRISA
10Ch
LATA
18Ch
ANSELA
20Ch
WPUA
28Ch
ODCONA
30Ch
SLRCONA
38Ch
INLVLA
00Dh
—
08Dh
—
10Dh
—
18Dh
—
20Dh
—
28Dh
—
30Dh
—
38Dh
—
00Eh
—
08Eh
—
10Eh
—
18Eh
—
20Eh
—
28Eh
—
30Eh
—
38Eh
—
00Fh
—
08Fh
—
10Fh
—
18Fh
—
20Fh
—
28Fh
—
30Fh
—
38Fh
—
010h
—
090h
—
110h
—
190h
—
210h
—
290h
—
310h
—
390h
—
011h
PIR1
091h
PIE1
111h
CM1CON0
191h
PMADRL
211h
—
291h
—
311h
—
391h
IOCAP
012h
PIR2
092h
PIE2
112h
CM1CON1
192h
PMADRH
212h
—
292h
—
312h
—
392h
IOCAN
013h
PIR3
093h
PIE3
113h
—
193h
PMDATL
213h
—
293h
—
313h
—
393h
IOCAF
014h
—
094h
—
114h
—
194h
PMDATH
214h
—
294h
—
314h
—
394h
—
015h
TMR0
095h
OPTION_REG
115h
CMOUT
195h
PMCON1
215h
—
295h
—
315h
—
395h
—
016h
TMR1L
096h
PCON
116h
BORCON
196h
PMCON2
216h
—
296h
—
316h
—
396h
—
017h
TMR1H
097h
WDTCON
117h
FVRCON
197h
VREGCON(1)
217h
—
297h
—
317h
—
397h
—
018h
T1CON
098h
OSCTUNE
118h
DAC1CON0
198h
—
218h
—
298h
—
318h
—
398h
—
019h
T1GCON
099h
OSCCON
119h
DAC1CON1
199h
RCREG
219h
—
299h
—
319h
—
399h
—
01Ah
TMR2
09Ah
OSCSTAT
11Ah
—
19Ah
TXREG
21Ah
—
29Ah
—
31Ah
—
39Ah
—
01Bh
PR2
09Bh
ADRESL
11Bh
—
19Bh
SPBRG
21Bh
—
29Bh
—
31Bh
—
39Bh
—
01Ch
T2CON
09Ch
ADRESH
11Ch
—
19Ch
SPBRGH
21Ch
—
29Ch
—
31Ch
—
39Ch
—
01Dh
—
09Dh
ADCON0
11Dh
APFCON
19Dh
RCSTA
21Dh
—
29Dh
—
31Dh
—
39Dh
—
01Eh
—
09Eh
ADCON1
11Eh
—
19Eh
TXSTA
21Eh
—
29Eh
—
31Eh
—
39Eh
—
01Fh
—
09Fh
0A0h
ADCON2
11Fh
—
19Fh
BAUDCON
21Fh
—
29Fh
—
31Fh
—
39Fh
—
020h
 2013-2015 Microchip Technology Inc.
General
Purpose
Register
80 Bytes
06Fh
General
Purpose
Register
80 Bytes
0EFh
0F0h
070h
0FFh
220h
1A0h
General
Purpose
Register
80 Bytes
16Fh
170h
Accesses
70h-7Fh
Common RAM
07Fh
120h
Unimplemented
Read as ‘0’
1EFh
1F0h
Accesses
70h-7Fh
17Fh
Legend:
= Unimplemented data memory locations, read as ‘0’.
Note 1: PIC12F1572 only.
Unimplemented
Read as ‘0’
26Fh
270h
Accesses
70h-7Fh
1FFh
2A0h
Unimplemented
Read as ‘0’
Unimplemented
Read as ‘0’
Unimplemented
Read as ‘0’
3EFh
370h
Accesses
70h-7Fh
2FFh
3A0h
36Fh
2EFh
2F0h
Accesses
70h-7Fh
27Fh
320h
3F0h
Accesses
70h-7Fh
37Fh
Accesses
70h-7Fh
3FFh
PIC12(L)F1571/2
DS40001723D-page 22
TABLE 3-4:
 2013-2015 Microchip Technology Inc.
TABLE 3-5:
PIC12(L)F1571/2 MEMORY MAP, BANK 8-23
BANK 8
400h
40Bh
40Ch
40Dh
40Eh
40Fh
410h
411h
412h
413h
414h
415h
416h
417h
418h
419h
41Ah
41Bh
41Ch
41Dh
41Eh
41Fh
420h
Core Registers
(Table 3-2)
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
BANK 9
480h
48Bh
48Ch
48Dh
48Eh
48Fh
490h
491h
492h
493h
494h
495h
496h
497h
498h
499h
49Ah
49Bh
49Ch
49Dh
49Eh
49Fh
4A0h
Unimplemented
Read as ‘0’
46Fh
470h
Core Registers
(Table 3-2)
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
56Fh
570h
4FFh
DS40001723D-page 23
80Bh
80Ch
88Bh
88Ch
Unimplemented
Read as ‘0’
86Fh
870h
Unimplemented
Read as ‘0’
8EFh
8F0h
Accesses
70h-7Fh
87Fh
Legend:
96Fh
970h
Accesses
70h-7Fh
8FFh
9EFh
9F0h
Accesses
70h-7Fh
97Fh
= Unimplemented data memory locations, read as ‘0’.
Accesses
70h-7Fh
9FFh
A7Fh
AFFh
7FFh
BANK 23
B80h
Core Registers
(Table 3-2)
B0Bh
B0Ch
Core Registers
(Table 3-2)
B8Bh
B8Ch
Unimplemented
Read as ‘0’
B6Fh
B70h
Accesses
70h-7Fh
Unimplemented
Read as ‘0’
BEFh
BF0h
Accesses
70h-7Fh
B7Fh
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
Accesses
70h-7Fh
BANK 22
Unimplemented
Read as ‘0’
Core Registers
(Table 3-2)
Unimplemented
Read as ‘0’
Accesses
70h-7Fh
Core Registers
(Table 3-2)
Accesses
70h-7Fh
78Bh
78Ch
78Dh
78Eh
78Fh
790h
791h
792h
793h
794h
795h
796h
797h
798h
799h
79Ah
79Bh
79Ch
79Dh
79Eh
79Fh
7A0h
7EFh
7F0h
B00h
AEFh
AF0h
BANK 15
780h
Unimplemented
Read as ‘0’
BANK 21
A8Bh
A8Ch
A6Fh
A70h
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
77Fh
A80h
Unimplemented
Read as ‘0’
Core Registers
(Table 3-2)
76Fh
770h
6FFh
A0Bh
A0Ch
70Bh
70Ch
70Dh
70Eh
70Fh
710h
711h
712h
713h
714h
715h
716h
717h
718h
719h
71Ah
71Bh
71Ch
71Dh
71Eh
71Fh
720h
Accesses
70h-7Fh
Core Registers
(Table 3-2)
Unimplemented
Read as ‘0’
—
—
—
—
—
CWG1DBR
CWG1DBF
CWG1CON0
CWG1CON1
CWG1CON2
—
—
—
—
—
—
—
—
—
—
BANK 14
700h
Unimplemented
Read as ‘0’
BANK 20
Core Registers
(Table 3-2)
Core Registers
(Table 3-2)
6EFh
6F0h
A00h
98Bh
98Ch
68Bh
68Ch
68Dh
68Eh
68Fh
690h
691h
692h
693h
694h
695h
696h
697h
698h
699h
69Ah
69Bh
69Ch
69Dh
69Eh
69Fh
6A0h
Accesses
70h-7Fh
BANK 19
Unimplemented
Read as ‘0’
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
67Fh
980h
Core Registers
(Table 3-2)
Core Registers
(Table 3-2)
BANK 13
680h
Unimplemented
Read as ‘0’
Accesses
70h-7Fh
BANK 18
90Bh
90Ch
60Bh
60Ch
60Dh
60Eh
60Fh
610h
611h
612h
613h
614h
615h
616h
617h
618h
619h
61Ah
61Bh
61Ch
61Dh
61Eh
61Fh
620h
66Fh
670h
5FFh
900h
Core Registers
(Table 3-2)
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
BANK 12
600h
Unimplemented
Read as ‘0’
Accesses
70h-7Fh
BANK 17
Core Registers
(Table 3-2)
5EFh
5F0h
57Fh
880h
Core Registers
(Table 3-2 )
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
58Bh
58Ch
58Dh
58Eh
58Fh
590h
591h
592h
593h
594h
595h
596h
597h
598h
599h
59Ah
59Bh
59Ch
59Dh
59Eh
59Fh
5A0h
Unimplemented
Read as ‘0’
Accesses
70h-7Fh
BANK 16
Core Registers
(Table 3-2)
BANK 11
580h
Accesses
70h-7Fh
BFFh
PIC12(L)F1571/2
Accesses
70h-7Fh
800h
50Bh
50Ch
50Dh
50Eh
50Fh
510h
511h
512h
513h
514h
515h
516h
517h
518h
519h
51Ah
51Bh
51Ch
51Dh
51Eh
51Fh
520h
Unimplemented
Read as ‘0’
4EFh
4F0h
47Fh
BANK 10
500h
PIC12(L)F1571/2 MEMORY MAP, BANK 24-31
BANK 24
C00h
BANK 25
Core Registers
(Table 3-2)
C0Bh
C0Ch
C0Dh
C0Eh
C0Fh
C10h
C11h
C12h
C13h
C14h
C15h
C16h
C17h
C18h
C19h
C1Ah
C1Bh
C1Ch
C1Dh
C1Eh
C1Fh
C20h
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
Core Registers
(Table 3-2)
C8Bh
C8Ch
C8Dh
C8Eh
C8Fh
C90h
C91h
C92h
C93h
C94h
C95h
C96h
C97h
C98h
C99h
C9Ah
C9Bh
C9Ch
C9Dh
C9Eh
C9Fh
CA0h
Unimplemented
Read as ‘0’
 2013-2015 Microchip Technology Inc.
C6Fh
C70h
Legend:
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
CEFh
CF0h
D0Bh
D0Ch
D0Dh
D0Eh
D0Fh
D10h
D11h
D12h
D13h
D14h
D15h
D16h
D17h
D18h
D19h
D1Ah
D1Bh
D1Ch
D1Dh
D1Eh
D1Fh
D20h
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
BANK 28
E00h
D8Bh
D8Ch
D6Fh
D70h
E0Bh
E0Ch
E0Dh
E0Eh
E0Fh
E10h
E11h
E12h
E13h
E14h
E15h
E16h
E17h
See Table 3-7 for E18h
Register Mapping
E19h
Details
E1Ah
E1Bh
E1Ch
E1Dh
E1Eh
E1Fh
E20h
Accesses
70h-7Fh
= Unimplemented data memory locations, read as ‘0’.
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
E6Fh
E70h
Accesses
70h-7Fh
DFFh
E8Bh
E8Ch
E8Dh
E8Eh
E8Fh
E90h
E91h
E92h
E93h
E94h
E95h
E96h
E97h
E98h
E99h
E9Ah
E9Bh
E9Ch
E9Dh
E9Eh
E9Fh
EA0h
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
EEFh
EF0h
F0Bh
F0Ch
F0Dh
F0Eh
F0Fh
F10h
F11h
F12h
F13h
F14h
F15h
F16h
F17h
F18h
F19h
F1Ah
F1Bh
F1Ch
F1Dh
F1Eh
F1Fh
F20h
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
Core Registers
(Table 3-2)
F8Bh
F8Ch
See Table 3-7 for
Register Mapping
Details
Unimplemented
Read as ‘0’
F6Fh
F70h
Accesses
70h-7Fh
EFFh
BANK 31
F80h
Core Registers
(Table 3-2)
Unimplemented
Read as ‘0’
Accesses
70h-7Fh
E7Fh
BANK 30
F00h
Core Registers
(Table 3-2)
Unimplemented
Read as ‘0’
DEFh
DF0h
D7Fh
BANK 29
E80h
Core Registers
(Table 3-2)
Core Registers
(Table 3-2)
Unimplemented
Read as ‘0’
Accesses
70h-7Fh
CFFh
BANK 27
D80h
Core Registers
(Table 3-2)
Unimplemented
Read as ‘0’
Accesses
70h-7Fh
CFFh
BANK 26
D00h
C80h
FEFh
FF0h
Accesses
70h-7Fh
F7Fh
Accesses
70h-7Fh
FFFh
PIC12(L)F1571/2
DS40001723D-page 24
TABLE 3-6:
PIC12(L)F1571/2
TABLE 3-7:
PIC12(L)F1571/2 MEMORY
MAP, BANK 27
TABLE 3-8:
PIC12(L)F1571/2 MEMORY
MAP, BANK 31
Bank 31
D8Ch
D8Dh
D8Eh
D8Fh
D90h
D91h
D92h
D93h
D94h
D95h
D96h
D97h
D98h
D99h
D9Ah
D9Bh
D9Ch
D9Dh
D9Eh
D9Fh
DA0h
DA1h
DA2h
DA3h
DA4h
DA5h
DA6h
DA7h
DA8h
DA9h
DAAh
DABh
DACh
DADh
DAEh
DAFh
DB0h
DB1h
DB2h
DB3h
DB4h
DB5h
DB6h
DB7h
DB8h
DB9h
DBAh
DBBh
DBCh
DBDh
DBEh
DBFh
DC0h
—
—
PWMEN
PWMLD
PWMOUT
PWM1PHL
PWM1PHH
PWM1DCL
PWM1DCH
PWM1PRL
PWM1PRH
PWM1OFL
PWM1OFH
PWM1TMRL
PWM1TMRH
PWM1CON
PWM1INTE
PWM1INTF
PWM1CLKCON
PWM1LDCON
PWM1OFCON
PWM2PHL
PWM2PHH
PWM2DCL
PWM2DCH
PWM2PRL
PWM2PRH
PWM2OFL
PWM2OFH
PWM2TMRL
PWM2TMRH
PWM2CON
PWM2INTE
PWM2INTF
PWM2CLKCON
PWM2LDCON
PWM2OFCON
PWM3PHL
PWM3PHH
PWM3DCL
PWM3DCH
PWM2PRL
PWM3PRH
PWM3OFL
PWM3OFH
PWM3TMRL
PWM3TMRH
PWM3CON
PWM3INTE
PWM3INTF
PWM3CLKCON
PWM3LDCON
PWM3OFCON
Bank 31
F8Ch
Unimplemented
Read as ‘0’
FE3h
FE4h
FE5h
FE6h
FE7h
FE8h
FE9h
FEAh
FEBh
FECh
FEDh
FEEh
FEFh
Legend:
STATUS_SHAD
WREG_SHAD
BSR_SHAD
PCLATH_SHAD
FSR0L_SHAD
FSR0H_SHAD
FSR1L_SHAD
FSR1H_SHAD
—
STKPTR
TOSL
TOSH
= Unimplemented data memory locations,
read as ‘0’.
DC1h
—
DEFh
Legend:
= Unimplemented data memory locations,
read as ‘0’.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 25
PIC12(L)F1571/2
3.3.6
CORE FUNCTION REGISTERS
SUMMARY
The Core Function registers listed in Table 3-9 can be
addressed from any bank.
TABLE 3-9:
Addr
Name
CORE FUNCTION REGISTERS SUMMARY
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on All
Other Resets
Bank 0-31
x00h or
INDF0
x80h
Addressing this location uses contents of FSR0H/FSR0L to address data memory
(not a physical register)
xxxx xxxx
uuuu uuuu
x01h or
INDF1
x81h
Addressing this location uses contents of FSR1H/FSR1L to address data memory
(not a physical register)
xxxx xxxx
uuuu uuuu
x02h or
PCL
x82h
Program Counter (PC) Least Significant Byte
0000 0000
0000 0000
---1 1000
---q quuu
x03h or
STATUS
x83h
—
—
—
TO
PD
Z
DC
C
x04h or
FSR0L
x84h
Indirect Data Memory Address 0 Low Pointer
0000 0000
uuuu uuuu
x05h or
FSR0H
x85h
Indirect Data Memory Address 0 High Pointer
0000 0000
0000 0000
x06h or
FSR1L
x86h
Indirect Data Memory Address 1 Low Pointer
0000 0000
uuuu uuuu
x07h or
FSR1H
x87h
Indirect Data Memory Address 1 High Pointer
0000 0000
0000 0000
---0 0000
---0 0000
0000 0000
uuuu uuuu
-000 0000
-000 0000
0000 0000
0000 0000
x08h or
BSR
x88h
x09h or
WREG
x89h
—
—
—
BSR<4:0>
Working Register
x0Ah or
PCLATH
x8Ah
—
x0Bh or
INTCON
x8Bh
GIE
Write Buffer for the Upper 7 bits of the Program Counter
PEIE
TMR0IE
INTE
IOCIE
TMR0IF
INTF
IOCIF
Legend: x = unknown; u = unchanged; q = value depends on condition; — = unimplemented, read as ‘0’; r = reserved.
Shaded locations are unimplemented, read as ‘0’.
DS40001723D-page 26
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
TABLE 3-10:
Addr
Name
SPECIAL FUNCTION REGISTER SUMMARY
Bit 7
Bit 6
—
—
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
All Other
Resets
Bank 0
00Ch
PORTA
RA<5:0>
--xx xxxx --xx xxxx
00Dh
—
Unimplemented
—
—
00Eh
—
Unimplemented
—
—
00Fh
—
Unimplemented
—
—
010h
—
Unimplemented
—
—
011h
PIR1
TMR1GIF
012h
PIR2
—
—
013h
PIR3
—
PWM3IF
014h
—
RCIF(2)
ADIF
TXIF(2)
—
—
TMR2IF
TMR1IF
0000 --00 0000 --00
C1IF
—
—
—
—
—
--0- ---- --0- ----
PWM2IF
PWM1IF
—
—
—
—
-000 ---- -000 ----
Unimplemented
—
—
015h
TMR0
Holding Register for the 8-Bit Timer0 Count
xxxx xxxx uuuu uuuu
016h
TMR1L
Holding Register for the Least Significant Byte of the 16-Bit TMR1 Count
xxxx xxxx uuuu uuuu
017h
TMR1H
Holding Register for the Most Significant Byte of the 16-Bit TMR1 Count
018h
T1CON
019h
T1GCON
TMR1CS<1:0>
TMR1GE
T1CKPS<1:0>
T1GPOL
01Ah
TMR2
Timer2 Module Register
01Bh
PR2
Timer2 Period Register
01Ch
T2CON
T1GTM
T1GSPM
xxxx xxxx uuuu uuuu
—
T1SYNC
T1GGO/
DONE
T1GVAL
—
TMR1ON
T1GSS<1:0>
0000 -0-0 uuuu -u-u
0000 0x00 uuuu uxuu
0000 0000 0000 0000
1111 1111 1111 1111
—
T2OUTPS<3:0>
TMR2ON
T2CKPS<1:0>
-000 0000 -000 0000
01Dh
—
Unimplemented
—
—
01Eh
—
Unimplemented
—
—
01Fh
—
Unimplemented
—
—
Bank 1
08Ch
TRISA
—
—
TRISA<5:4>
—(2)
TRISA<2:0>
--11 1111 --11 1111
08Dh
—
Unimplemented
—
—
08Eh
—
Unimplemented
—
—
08Fh
—
Unimplemented
—
—
090h
—
Unimplemented
—
—
091h
PIE1
TMR1GIE
092h
PIE2
—
—
093h
PIE3
—
PWM3IE
RCIE(2)
ADIE
TXIE(2)
—
—
TMR2IE
TMR1IE
0000 --00 0000 --00
C1IE
—
—
—
—
—
--0- ---- --0- ----
PWM2IE
PWM1IE
—
—
—
—
-000 ---- -000 ----
PSA
094h
—
095h
OPTION_REG
WPUEN
INTEDG
TMR0CS
TMR0SE
096h
PCON
STKOVF
STKUNF
—
RWDT
097h
WDTCON
—
—
098h
OSCTUNE
—
—
099h
OSCCON
SPLLEN
09Ah
OSCSTAT
—
09Bh
ADRESL
ADC Result Register Low
xxxx xxxx uuuu uuuu
09Ch
ADRESH
ADC Result Register High
xxxx xxxx uuuu uuuu
09Dh
ADCON0
—
09Eh
ADCON1
ADFM
09Fh
ADCON2
Legend:
Note 1:
2:
3:
Unimplemented
—
PS<2:0>
RMCLR
RI
POR
WDTPS<4:0>
BOR
00-1 11qq qq-q qquu
SWDTEN
--01 0110 --01 0110
TUN<5:0>
IRCF<3:0>
PLLR
OSTS
HFIOFR
MFIOFR
CHS<4:0>
ADCS<2:0>
TRIGSEL<3:0>
--00 0000 --00 0000
—
HFIOFL
SCS<1:0>
LFIOFR
GO/DONE
—
—
—
—
—
1111 1111 1111 1111
0011 1-00 0011 1-00
HFIOFS
ADON
ADPREF<1:0>
—
—
-0q0 0q00 -qqq qqqq
-000 0000 -000 0000
0000 --00 0000 --00
0000 ---- 0000 ----
x = unknown; u = unchanged; q = value depends on condition; — = unimplemented; r = reserved. Shaded locations are unimplemented, read as ‘0’.
PIC12F1571/2 only.
PIC12(L)F1572 only.
Unimplemented, read as ‘1’.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 27
PIC12(L)F1571/2
TABLE 3-10:
Addr
SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED)
Name
Bit 7
Bit 6
—
—
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
All Other
Resets
Bank 2
10Ch
LATA
LATA<5:4>
—
LATA<2:0>
--xx -xxx --uu -uuu
10Dh
—
Unimplemented
—
—
10Eh
—
Unimplemented
—
—
10Fh
—
Unimplemented
—
—
110h
—
Unimplemented
—
—
111h
CM1CON0
112h
CM1CON1
C1ON
C1OUT
C1INTP
C1INTN
C1OE
C1POL
—
C1PCH<1:0>
C1SP
—
C1HYS
C1SYNC
C1NCH<2:0>
0000 -100 0000 -100
0000 -000 0000 -000
113h
—
Unimplemented
—
—
114h
—
Unimplemented
—
—
115h
CMOUT
—
—
—
—
—
—
—
MC1OUT
---- ---0 ---- ---0
—
—
—
BORRDY
10-- ---q uu-- ---u
116h
BORCON
SBOREN
BORFS
—
—
117h
FVRCON
FVREN
FVRRDY
TSEN
TSRNG
CDAFVR<1:0>
118h
DAC1CON0
DACEN
—
DACOE
—
DACPSS<1:0>
119h
DAC1CON1
—
—
—
11Ah
to
11Ch
—
ADFVR<1:0>
—
0q00 0000 0q00 0000
—
DACR<4:0>
0-0- 00-- 0-0- 00----0 0000 ---0 0000
Unimplemented
—
RXDTSEL CWGASEL CWGBSEL
—
11Dh
APFCON
11Eh
—
Unimplemented
—
—
11Fh
—
Unimplemented
—
—
—
T1GSEL
TXCKSEL
P2SEL
P1SEL
000- 0000 000- 0000
Bank 3
18Ch
ANSELA
18Dh
—
Unimplemented
—
—
18Eh
—
Unimplemented
—
—
18Fh
—
Unimplemented
—
—
190h
—
Unimplemented
—
—
191h
PMADRL
192h
PMADRH
193h
PMDATL
194h
PMDATH
—
—
195h
PMCON1
—(3)
CFGS
196h
PMCON2
197h
VREGCON(1)
198h
—
—
—
—
ANSA4
—
ANSA<2:0>
---1 -111 ---1 -111
Flash Program Memory Address Register Low Byte
—(3)
0000 0000 0000 0000
Flash Program Memory Address Register High Byte
1000 0000 1000 0000
Flash Program Memory Read Data Register Low Byte
xxxx xxxx uuuu uuuu
Flash Program Memory Read Data Register High Byte
LWLO
FREE
--xx xxxx --uu uuuu
WRERR
WREN
WR
RD
—
—
VREGPM
Reserved
Flash Program Memory Control Register 2
—
—
—
1000 x000 1000 q000
0000 0000 0000 0000
—
Unimplemented
---- --01 ---- --01
—
—
199h
RCREG
USART Receive Data Register
0000 0000 0000 0000
19Ah
TXREG
USART Transmit Data Register
0000 0000 0000 0000
19Bh
SPBRGL
Baud Rate Generator Data Register Low
0000 0000 0000 0000
19Ch
SPBRGH
Baud Rate Generator Data Register High
19Dh
RCSTA
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
0000 000x 0000 000x
19Eh
TXSTA
CSRC
TX9
TXEN
SYNC
SENDB
BRGH
TRMT
TX9D
0000 0010 0000 0010
19Fh
BAUDCON
ABDOVF
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
01-0 0-00 01-0 0-00
Legend:
Note 1:
2:
3:
0000 0000 0000 0000
x = unknown; u = unchanged; q = value depends on condition; — = unimplemented; r = reserved. Shaded locations are unimplemented, read as ‘0’.
PIC12F1571/2 only.
PIC12(L)F1572 only.
Unimplemented, read as ‘1’.
DS40001723D-page 28
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
TABLE 3-10:
Addr
Name
SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED)
Bit 7
Bit 6
—
—
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
All Other
Resets
Bank 4
20Ch
WPUA
WPUA<5:0>
--11 1111 --11 1111
20Dh
—
Unimplemented
—
—
20Eh
to
21Fh
—
Unimplemented
—
—
Bank 5
28Ch
ODCONA
28Dh
to
29Fh
—
—
—
ODA<5:4>
—
ODA<2:0>
Unimplemented
--11 -111 --11 -111
—
—
Bank 6
30Ch
SLRCONA
30Dh
to
31Fh
—
—
—
SLRA<5:4>
—
SLRA<2:0>
Unimplemented
--11 -111 --11 -111
—
—
Bank 7
38Ch
INLVLA
38Dh
to
390h
—
—
—
INLVLA<5:0>
Unimplemented
--11 1111 --11 1111
—
—
391h
IOCAP
—
—
IOCAP<5:0>
--00 0000 --00 0000
392h
IOCAN
—
—
IOCAN<5:0>
--00 0000 --00 0000
393h
IOCAF
—
—
IOCAF<5:0>
--00 0000 --00 0000
394h
to
39Fh
—
Unimplemented
—
—
—
Unimplemented
—
—
—
Unimplemented
—
—
Bank 8
40Ch
to
41Fh
Bank 9
48Ch
to
49Fh
Legend:
Note 1:
2:
3:
x = unknown; u = unchanged; q = value depends on condition; — = unimplemented; r = reserved. Shaded locations are unimplemented, read as ‘0’.
PIC12F1571/2 only.
PIC12(L)F1572 only.
Unimplemented, read as ‘1’.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 29
PIC12(L)F1571/2
TABLE 3-10:
Addr
SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED)
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
All Other
Resets
Bank 10
50Ch
to
51Fh
—
Unimplemented
—
—
—
Unimplemented
—
—
—
Unimplemented
—
—
—
Unimplemented
—
—
Bank 11
58Ch
to
59Fh
Bank 12
60Ch
to
61Fh
Bank 13
68Ch
to
690h
691h
CWG1DBR
—
—
CWG1DBR<5:0>
692h
CWG1DBF
—
—
CWG1DBF<5:0>
693h
CWG1CON0
G1EN
G1OEB
694h
CWG1CON1
695h
CWG1CON2
696h
to
69Fh
G1ASDLB<1:0>
G1ASE
G1ARSEN
G1OEA
G1POLB
G1POLA
G1ASDLA<1:0>
—
—
—
—
—
--00 0000 --00 0000
--xx xxxx --xx xxxx
—
G1CS0
G1IS<2:0>
G1ASDSC1
G1ASDSFLT
0000 0--0 0000 0--0
0000 -000 0000 -000
—
00-- -00- 00-- -00-
—
Unimplemented
—
—
—
Unimplemented
—
—
Banks 14-26
x0Ch/
x8Ch
—
x1Fh/
x9Fh
Legend:
Note 1:
2:
3:
x = unknown; u = unchanged; q = value depends on condition; — = unimplemented; r = reserved. Shaded locations are unimplemented, read as ‘0’.
PIC12F1571/2 only.
PIC12(L)F1572 only.
Unimplemented, read as ‘1’.
DS40001723D-page 30
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
TABLE 3-10:
Addr
SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED)
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
All Other
Resets
Bank 27
D8Ch
—
Unimplemented
—
—
D8Dh
—
Unimplemented
—
—
D8Eh
PWMEN
—
—
—
—
—
D8Fh
PWMLD
—
—
—
—
—
PWM3LDA_A PWM2LDA_A PWM1LDA_A ---- -000 ---- -000
D90h
PWMOUT
—
—
—
—
—
PWM3OUT_A PWM2OUT_A PWM1OUT_A ---- -000 ---- -000
D91h
PWM1PHL
PH<7:0>
xxxx xxxx uuuu uuuu
D92h
PWM1PHH
PH<15:8>
xxxx xxxx uuuu uuuu
D93h
PWM1DCL
DC<7:0>
xxxx xxxx uuuu uuuu
D94h
PWM1DCH
DC<15:8>
xxxx xxxx uuuu uuuu
D95h
PWM1PRL
PR<7:0>
xxxx xxxx uuuu uuuu
D96h
PWM1PRH
PR<15:8>
xxxx xxxx uuuu uuuu
D97h
PWM1OFL
OF<7:0>
xxxx xxxx uuuu uuuu
D98h
PWM1OFH
OF<15:8>
xxxx xxxx uuuu uuuu
D99h
PWM1TMRL
TMR<7:0>
xxxx xxxx uuuu uuuu
D9Ah
PWM1TMRH
TMR<15:8>
D9Bh
PWM1CON
PWM1EN
D9Ch
PWM1INTE
—
—
—
—
PWM1OFIE
D9Dh
PWM1INTF
—
—
—
—
D9Eh
PWM1CLKCON
—
PWM1OE PWM1OUT PWM1POL
PWM2EN_A
PWM1EN_A ---- -000 ---- -000
xxxx xxxx uuuu uuuu
PWM1MODE<1:0>
—
—
PWM1PHIE
PWM1DCIE
PWM1PRIE
---- 000
---- 000
PWM1OFIF
PWM1PHIF
PWM1DCIF
PWM1PRIF
---- 000
---- 000
—
—
—
—
PWM1OFO
—
PWM1PS<2:0>
PWM1LDA PWM1LDT
PWM3EN_A
PWM1CS<1:0>
-000 -000 -000 --00
—
PWM1LDS<1:0>
00-- -000 00-- --00
—
PWM1OFS<1:0>
-000 -000 -000 --00
D9Fh
PWM1LDCON
DA0h
PWM1OFCON
DA1h
PWM2PHL
PH<7:0>
xxxx xxxx uuuu uuuu
DA2h
PWM2PHH
PH<15:8>
xxxx xxxx uuuu uuuu
DA3h
PWM2DCL
DC<7:0>
xxxx xxxx uuuu uuuu
DA4h
PWM2DCH
DC<15:8>
xxxx xxxx uuuu uuuu
DA5h
PWM2PRL
PR<7:0>
xxxx xxxx uuuu uuuu
DA6h
PWM2PRH
PR<15:8>
xxxx xxxx uuuu uuuu
DA7h
PWM2OFL
OF<7:0>
xxxx xxxx uuuu uuuu
DA8h
PWM2OFH
OF<15:8>
xxxx xxxx uuuu uuuu
DA9h
PWM2TMRL
TMR<7:0>
xxxx xxxx uuuu uuuu
DAAh PWM2TMRH
TMR<15:8>
—
—
0000 00-- 0000 00--
PWM1OFM<1:0>
DABh PWM2CON
PWM2EN
DACh PWM2INTE
—
—
—
—
PWM2OFIE
DADh PWM2INTF
—
—
—
—
DAEh PWM2CLKCON
—
DAFh
PWM2LDCON
Legend:
Note 1:
2:
3:
PWM2OE PWM2OUT PWM2POL
PWM2PS<2:0>
PWM2LDA PWM2LDT
—
—
xxxx xxxx uuuu uuuu
PWM2MODE<1:0>
—
—
PWM2PHIE
PWM2DCIE
PWM2PRIE
---- 000
---- 000
PWM2OFIF
PWM2PHIF
PWM2DCIF
PWM2PRIF
---- 000
---- 000
—
—
PWM2CS<1:0>
-000 -000 -000 --00
—
—
PWM2LDS<1:0>
00-- -000 00-- --00
0000 00-- 0000 00--
x = unknown; u = unchanged; q = value depends on condition; — = unimplemented; r = reserved. Shaded locations are unimplemented, read as ‘0’.
PIC12F1571/2 only.
PIC12(L)F1572 only.
Unimplemented, read as ‘1’.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 31
PIC12(L)F1571/2
TABLE 3-10:
Addr
SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED)
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
—
—
Bit 1
Bit 0
Value on
POR, BOR
Value on
All Other
Resets
Bank 27 (Continued)
DB0h
PWM2OFCON
DB1h
PWM3PHL
—
PWM2OFM<1:0>
PWM2OFO
PH<7:0>
xxxx xxxx uuuu uuuu
DB2h
PWM3PHH
PH<15:8>
xxxx xxxx uuuu uuuu
DB3h
PWM3DCL
DC<7:0>
xxxx xxxx uuuu uuuu
DB4h
PWM3DCH
DC<15:8>
xxxx xxxx uuuu uuuu
DB5h
PWM3PRL
PR<7:0>
xxxx xxxx uuuu uuuu
DB6h
PWM3PRH
PR<15:8>
xxxx xxxx uuuu uuuu
DB7h
PWM3OFL
OF<7:0>
xxxx xxxx uuuu uuuu
DA8h
PWM3OFH
OF<15:8>
xxxx xxxx uuuu uuuu
DA9h
PWM3TMRL
TMR<7:0>
xxxx xxxx uuuu uuuu
DBAh PWM3TMRH
TMR<15:8>
DBBh PWM3CON
PWM3EN
DBCh PWM3INTE
—
—
—
—
PWM3OFIE
DBDh PWM3INTF
—
—
—
—
DBEh PWM3CLKCON
—
DBFh
PWM3LDCON
DC0h
PWM3OFCON
PWM3OE PWM3OUT PWM3POL
—
—
PWM3OFM<1:0>
-000 -000 -000 --00
xxxx xxxx uuuu uuuu
—
—
PWM3PHIE
PWM3DCIE
PWM3PRIE
---- 000
---- 000
PWM3OFIF
PWM3PHIF
PWM3DCIF
PWM3PRIF
---- 000
---- 000
—
—
—
—
PWM3OFO
—
PWM3PS<2:0>
PWM3LDA PWM3LDT
PWM2OFS<1:0>
PWM3MODE<1:0>
0000 00-- 0000 00--
PWM3CS<1:0>
-000 -000 -000 --00
—
PWM3LDS<1:0>
00-- -000 00-- --00
—
PWM3OFS<1:0>
-000 -000 -000 --00
Bank 28-30
58Ch
to
59Fh
Legend:
Note 1:
2:
3:
—
Unimplemented
—
—
x = unknown; u = unchanged; q = value depends on condition; — = unimplemented; r = reserved. Shaded locations are unimplemented, read as ‘0’.
PIC12F1571/2 only.
PIC12(L)F1572 only.
Unimplemented, read as ‘1’.
DS40001723D-page 32
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
TABLE 3-10:
Addr
Name
SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
All Other
Resets
—
—
Bank 31
F8Ch
—
FE3h
—
FE4h
STATUS_
SHAD
FE5h
WREG_
SHAD
FE6h
BSR_
PCLATH_
SHAD
FE8h
FSR0L_
SHAD
FE9h
FSR0H_
SHAD
FEAh
FSR1L_
SHAD
FEBh
FSR1H_
SHAD
FECh
—
FEDh
STKPTR
FEEh
TOSL
FEFh
TOSH
Legend:
Note 1:
2:
3:
—
—
—
—
—
Z_SHAD
Working Register Shadow
—
SHAD
FE7h
Unimplemented
—
—
DC_SHAD
C_SHAD
---- -xxx ---- -uuu
xxxx xxxx uuuu uuuu
—
Bank Select Register Shadow
Program Counter Latch High Register Shadow
---x xxxx ---u uuuu
-xxx xxxx uuuu uuuu
Indirect Data Memory Address 0 Low Pointer Shadow
xxxx xxxx uuuu uuuu
Indirect Data Memory Address 0 High Pointer Shadow
xxxx xxxx uuuu uuuu
Indirect Data Memory Address 1 Low Pointer Shadow
xxxx xxxx uuuu uuuu
Indirect Data Memory Address 1 High Pointer Shadow
xxxx xxxx uuuu uuuu
Unimplemented
—
—
—
—
Top-of-Stack Low Byte
—
Top-of-Stack High Byte
Current Stack Pointer
—
---1 1111 ---1 1111
xxxx xxxx uuuu uuuu
-xxx xxxx -uuu uuuu
x = unknown; u = unchanged; q = value depends on condition; — = unimplemented; r = reserved. Shaded locations are unimplemented, read as ‘0’.
PIC12F1571/2 only.
PIC12(L)F1572 only.
Unimplemented, read as ‘1’.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 33
PIC12(L)F1571/2
3.4
PCL and PCLATH
3.4.2
The Program Counter (PC) is 15 bits wide. The low byte
comes from the PCL register, which is a readable and
writable register. The high byte (PC<14:8>) is not directly
readable or writable and comes from PCLATH. On any
Reset, the PC is cleared. Figure 3-4 shows the five
situations for the loading of the PC.
FIGURE 3-4:
LOADING OF PC IN
DIFFERENT SITUATIONS
Rev. 10-000042A
7/30/2013
14
PCH
PCL
0
PC
7
6
8
0
PCLATH
Instruction
with PCL as
Destination
ALU result
14
PCH
PCL
0
PC
6
4
0
PCLATH
GOTO,
CALL
11
OPCODE <10:0>
14
PCH
PCL
0
PC
6
7
0
PCLATH
14
PCH
CALLW
8
W
PCL
0
PCL
0
PC
BRW
15
PC + W
14
PCH
PC
BRA
15
PC + OPCODE <8:0>
3.4.1
COMPUTED GOTO
A computed GOTO is accomplished by adding an offset to
the Program Counter (ADDWF PCL). When performing a
table read using a computed GOTO method, care should
be exercised if the table location crosses a PCL memory
boundary (each 256-byte block). Refer to Application
Note AN556, “Implementing a Table Read” (DS00556).
3.4.3
COMPUTED FUNCTION CALLs
A computed function CALL allows programs to maintain
tables of functions and provides another way to
execute state machines or look-up tables. When performing a table read using a computed function CALL,
care should be exercised if the table location crosses a
PCL memory boundary (each 256-byte block).
If using the CALL instruction, the PCH<2:0> and PCL
registers are loaded with the operand of the CALL
instruction. PCH<6:3> is loaded with PCLATH<6:3>.
The CALLW instruction enables computed CALLs by
combining PCLATH and W to form the destination
address. A computed CALLW is accomplished by
loading the W register with the desired address and
executing CALLW. The PCL register is loaded with the
value of W and PCH is loaded with PCLATH.
3.4.4
BRANCHING
The branching instructions add an offset to the PC.
This allows relocatable code and code that crosses
page boundaries. There are two forms of branching,
BRW and BRA. The PC will have incremented to fetch
the next instruction in both cases. When using either
branching instruction, a PCL memory boundary may be
crossed.
If using BRW, load the W register with the desired
unsigned address and execute BRW. The entire PC will
be loaded with the address, PC + 1 + W.
If using BRA, the entire PC will be loaded with PC + 1 +,
the signed value of the operand of the BRA instruction.
MODIFYING PCL
Executing any instruction with the PCL register as the
destination simultaneously causes the Program
Counter PC<14:8> bits (PCH) to be replaced by the
contents of the PCLATH register. This allows the entire
contents of the Program Counter to be changed by
writing the desired upper seven bits to the PCLATH
register. When the lower eight bits are written to the
PCL register, all 15 bits of the Program Counter will
change to the values contained in the PCLATH register
and those being written to the PCL register.
DS40001723D-page 34
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
3.5
Stack
3.5.1
All devices have a 16-level x 15-bit wide hardware
stack (refer to Figures 3-5 through 3-8). The stack
space is not part of either program or data space. The
PC is PUSHed onto the stack when CALL or CALLW
instructions are executed, or an interrupt causes a
branch. The stack is POPed in the event of a RETURN,
RETLW or RETFIE instruction execution. PCLATH is
not affected by a PUSH or POP operation.
The stack operates as a circular buffer if the STVREN
bit is programmed to ‘0’ (Configuration Words). This
means that after the stack has been PUSHed sixteen
times, the seventeenth PUSH overwrites the value that
was stored from the first PUSH. The eighteenth PUSH
overwrites the second PUSH (and so on). The
STKOVF and STKUNF flag bits will be set on an
overflow/underflow, regardless of whether the Reset is
enabled.
Note 1: There are no instructions/mnemonics
called PUSH or POP. These are actions
that occur from the execution of the
CALL, CALLW, RETURN, RETLW and
RETFIE instructions or the vectoring to
an interrupt address.
FIGURE 3-5:
ACCESSING THE STACK
The stack is available through the TOSH, TOSL and
STKPTR registers. STKPTR is the current value of the
Stack Pointer. The TOSH:TOSL register pair points to
the top of the stack. Both registers are read/writable.
TOS is split into TOSH and TOSL due to the 15-bit size
of the PC. To access the stack, adjust the value of
STKPTR, which will position TOSH:TOSL, then
read/write to TOSH:TOSL. The STKPTR is 5 bits to
allow detection of overflow and underflow.
Note:
Care should be taken when modifying the
STKPTR while interrupts are enabled.
During normal program operation, CALL, CALLW and
interrupts will increment STKPTR while RETLW,
RETURN and RETFIE will decrement STKPTR. At any
time, the STKPTR can be inspected to see how much
stack is left. The STKPTR always points at the currently
used place on the stack. Therefore, a CALL or CALLW
will increment the STKPTR and then write the PC, and
a return will unload the PC and then decrement the
STKPTR.
Reference Figure 3-5 through Figure 3-8 for examples
of accessing the stack.
ACCESSING THE STACK EXAMPLE 1
Rev. 10-000043A
7/30/2013
TOSH:TOSL
0x0F
STKPTR = 0x1F
Stack Reset Disabled
(STVREN = 0)
0x0E
0x0D
0x0C
0x0B
Initial Stack Configuration:
0x0A
After Reset, the stack is empty. The
empty stack is initialized so the Stack
Pointer is pointing at 0x1F. If the Stack
Overflow/Underflow Reset is enabled, the
TOSH/TOSL register will return ‘0’. If the
Stack Overflow/Underflow Reset is
disabled, the TOSH/TOSL register will
return the contents of stack address
0x0F.
0x09
0x08
0x07
0x06
0x05
0x04
0x03
0x02
0x01
0x00
TOSH:TOSL
 2013-2015 Microchip Technology Inc.
0x1F
0x0000
STKPTR = 0x1F
Stack Reset Enabled
(STVREN = 1)
DS40001723D-page 35
PIC12(L)F1571/2
FIGURE 3-6:
ACCESSING THE STACK EXAMPLE 2
Rev. 10-000043B
7/30/2013
0x0F
0x0E
0x0D
0x0C
0x0B
0x0A
This figure shows the stack configuration
after the first CALL or a single interrupt.
If a RETURN instruction is executed, the
return address will be placed in the
Program Counter and the Stack Pointer
decremented to the empty state (0x1F).
0x09
0x08
0x07
0x06
0x05
0x04
0x03
0x02
0x01
0x00
TOSH:TOSL
FIGURE 3-7:
Return Address
STKPTR = 0x00
ACCESSING THE STACK EXAMPLE 3
Rev. 10-000043C
7/30/2013
0x0F
0x0E
0x0D
0x0C
After seven CALLs or six CALLs and an
interrupt, the stack looks like the figure on
the left. A series of RETURN instructions will
repeatedly place the return addresses into
the Program Counter and pop the stack.
0x0B
0x0A
0x09
0x08
0x07
TOSH:TOSL
DS40001723D-page 36
0x06
Return Address
0x05
Return Address
0x04
Return Address
0x03
Return Address
0x02
Return Address
0x01
Return Address
0x00
Return Address
STKPTR = 0x06
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
FIGURE 3-8:
ACCESSING THE STACK EXAMPLE 4
Rev. 10-000043D
7/30/2013
TOSH:TOSL
3.5.2
0x0F
Return Address
0x0E
Return Address
0x0D
Return Address
0x0C
Return Address
0x0B
Return Address
0x0A
Return Address
0x09
Return Address
0x08
Return Address
0x07
Return Address
0x06
Return Address
0x05
Return Address
0x04
Return Address
0x03
Return Address
0x02
Return Address
0x01
Return Address
0x00
Return Address
OVERFLOW/UNDERFLOW RESET
If the STVREN bit in the Configuration Words is
programmed to ‘1’, the device will be reset if the stack
is PUSHed beyond the sixteenth level or POPed
beyond the first level, setting the appropriate bits
(STKOVF or STKUNF, respectively) in the PCON
register.
3.6
When the stack is full, the next CALL or
an interrupt will set the Stack Pointer to
0x10. This is identical to address 0x00 so
the stack will wrap and overwrite the
return address at 0x00. If the Stack
Overflow/Underflow Reset is enabled, a
Reset will occur and location 0x00 will
not be overwritten.
STKPTR = 0x10
Indirect Addressing
The INDFn registers are not physical registers. Any
instruction that accesses an INDFn register actually
accesses the register at the address specified by the
File Select Registers (FSR). If the FSRn address
specifies one of the two INDFn registers, the read will
return ‘0’ and the write will not occur (though Status bits
may be affected). The FSRn register value is created
by the pair, FSRnH and FSRnL.
The FSR registers form a 16-bit address that allows an
addressing space with 65536 locations. These locations
are divided into three memory regions:
• Traditional Data Memory
• Linear Data Memory
• Program Flash Memory
 2013-2015 Microchip Technology Inc.
DS40001723D-page 37
PIC12(L)F1571/2
FIGURE 3-9:
INDIRECT ADDRESSING
Rev. 10-000044A
7/30/2013
0x0000
0x0000
Traditional
Data Memory
0x0FFF
0x1000
0x0FFF
Reserved
0x1FFF
0x2000
Linear
Data Memory
0x29AF
0x29B0
Reserved
FSR
Address
Range
0x7FFF
0x8000
0x0000
Program
Flash Memory
0xFFFF
Note:
0x7FFF
Not all memory regions are completely implemented. Consult device memory tables for memory limits.
DS40001723D-page 38
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
3.6.1
TRADITIONAL DATA MEMORY
The traditional data memory is a region from FSR
address, 0x000, to FSR address, 0xFFF. The
addresses correspond to the absolute addresses of all
SFR, GPR and common registers.
FIGURE 3-10:
TRADITIONAL DATA MEMORY MAP
Rev. 10-000056A
7/31/2013
Direct Addressing
4 BSR 0
Indirect Addressing
From Opcode
6
0
Bank Select
7
FSRxH
0 0 0 0
Location Select
0x00
00000
Bank Select
00001
00010
11111
Bank 0 Bank 1
Bank 2
Bank 31
0 7
FSRxL
0
Location Select
0x7F
 2013-2015 Microchip Technology Inc.
DS40001723D-page 39
PIC12(L)F1571/2
3.6.2
LINEAR DATA MEMORY
The linear data memory is the region from FSR
address, 0x2000, to FSR address, 0x29AF. This region
is a virtual region that points back to the 80-byte blocks
of GPR memory in all the banks.
Unimplemented memory reads as 0x00. Use of the
linear data memory region allows buffers to be larger
than 80 bytes because incrementing the FSR beyond
one bank will go directly to the GPR memory of the next
bank.
The 16 bytes of common memory are not included in
the linear data memory region.
FIGURE 3-11:
LINEAR DATA MEMORY
MAP
3.6.3
PROGRAM FLASH MEMORY
To make constant data access easier, the entire
Program Flash Memory is mapped to the upper half of
the FSR address space. When the MSb of FSRnH is
set, the lower 15 bits are the address in program
memory which will be accessed through INDF. Only the
lower eight bits of each memory location are accessible
via INDF. Writing to the Program Flash Memory cannot
be accomplished via the FSR/INDF interface. All
instructions that access Program Flash Memory via the
FSR/INDF interface will require one additional
instruction cycle to complete.
FIGURE 3-12:
PROGRAM FLASH
MEMORY MAP
Rev. 10-000057A
7/31/2013
7
FSRnH
0 0 1
0
Location Select
7
FSRnL
Rev. 10-000058A
7/31/2013
7
1
0
FSRnH
0
Location Select
0x2000
7
FSRnL
0
0x8000
0x020
Bank 0
0x06F
0x0A0
Bank 1
0x0EF
Program
Flash
Memory
(low 8 bits)
0x120
Bank 2
0x16F
0x29AF
DS40001723D-page 40
0xF20
Bank 30
0xF6F
0x0000
0xFFFF
0x7FFF
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
4.0
DEVICE CONFIGURATION
Device configuration consists of Configuration Words,
code protection and Device ID.
4.1
Configuration Words
Note:
The DEBUG bit in the Configuration Words
is managed automatically by device
development tools, including debuggers
and programmers. For normal device
operation, this bit should be maintained as
a ‘1’.
There are several Configuration Word bits that allow
different oscillator and memory protection options.
These are implemented as Configuration Word 1 at
8007h and Configuration Word 2 at 8008h.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 41
PIC12(L)F1571/2
4.2
Register Definitions: Configuration Words
REGISTER 4-1:
CONFIG1: CONFIGURATION WORD 1
U-1
U-1
—
—
R/P-1
CLKOUTEN
R/P-1
R/P-1
BOREN<1:0>
U-1
(1)
—
bit 13
R/P-1
(2)
CP
R/P-1
MCLRE
bit 8
R/P-1
PWRTE
R/P-1
(1)
R/P-1
WDTE<1:0>
U-1
R/P-1
—
R/P-1
FOSC<1:0>
bit 7
bit 0
Legend:
R = Readable bit
P = Programmable bit
U = Unimplemented bit, read as ‘1’
‘0’ = Bit is cleared
‘1’ = Bit is set
n = Value when blank or after bulk erase
bit 13-12
Unimplemented: Read as ‘1’
bit 11
CLKOUTEN: Clock Out Enable bit
1 = Off – CLKOUT function is disabled; I/O or oscillator function on CLKOUT pin
0 = On – CLKOUT function is enabled on CLKOUT pin
bit 10-9
BOREN<1:0>: Brown-out Reset Enable bits(1)
11 = On
– Brown-out Reset is enabled; the SBOREN bit is ignored
10 = Sleep
– Brown-out Reset is enabled while running and disabled in Sleep; the SBOREN bit is ignored
01 = SBODEN – Brown-out Reset is controlled by the SBOREN bit in the BORCON register
00 = Off
– Brown-out Reset is disabled; the SBOREN bit is ignored
bit 8
Unimplemented: Read as ‘1’
bit 7
CP: Flash Program Memory Code Protection bit(2)
1 = Off – Code protection is off; program memory can be read and written
0 = On – Code protection is on; program memory cannot be read or written externally
bit 6
MCLRE: MCLR/VPP Pin Function Select bit
If LVP bit = 1 (On):
This bit is ignored. MCLR/VPP pin function is MCLR; weak pull-up is enabled.
If LVP bit = 0 (Off):
1 = On – MCLR/VPP pin function is MCLR; weak pull-up is enabled
0 = Off – MCLR/VPP pin function is a digital input, MCLR is internally disabled; weak pull-up is under control
of pin’s WPU control bit
bit 5
PWRTE: Power-up Timer Enable bit(1)
1 = Off – PWRT is disabled
0 = On – PWRT is enabled
bit 4-3
WDTE<1:0>: Watchdog Timer Enable bits
11 = On
– WDT is enabled; SWDTEN is ignored
10 = Sleep
– WDT is enabled while running and disabled in Sleep; SWDTEN is ignored
01 = SWDTEN – WDT is controlled by the SWDTEN bit in the WDTCON register
00 = Off
– WDT is disabled; SWDTEN is ignored
bit 2
Unimplemented: Read as ‘1’
bit 1-0
FOSC<1:0>: Oscillator Selection bits
11 = ECH
– External Clock, High-Power mode: CLKI on CLKI
10 = ECM
– External Clock, Medium Power mode: CLKI on CLKI
– External Clock, Low-Power mode: CLKI on CLKI
01 = ECL
00 = INTOSC – I/O function on CLKI
Note 1:
2:
Enabling Brown-out Reset does not automatically enable the Power-up Timer.
Once enabled, code-protect can only be disabled by bulk erasing the device.
DS40001723D-page 42
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PIC12(L)F1571/2
REGISTER 4-2:
CONFIG2: CONFIGURATION WORD 2
R/P-1
(1)
LVP
R/P-1
DEBUG
R/P-1
(2)
LPBOREN
R/P-1
(3)
BORV
R/P-1
R/P-1
STVREN
PLLEN
bit 13
bit 8
U-1
U-1
U-1
U-1
U-1
U-1
—
—
—
—
—
—
R/P-1
R/P-1
WRT<1:0>
bit 7
bit 0
Legend:
R = Readable bit
P = Programmable bit
U = Unimplemented bit, read as ‘1’
‘0’ = Bit is cleared
‘1’ = Bit is set
n = Value when blank or after bulk erase
bit 13
LVP: Low-Voltage Programming Enable bit(1)
1 = On – Low-voltage programming is enabled, MCLR/VPP pin function is MCLR; MCLRE
Configuration bit is ignored
0 = Off – High voltage on MCLR/VPP must be used for programming
bit 12
DEBUG: Debugger Mode bit(2)
1 = Off – In-Circuit Debugger is disabled; ICSPCLK and ICSPDAT are general purpose I/O pins
0 = On – In-Circuit Debugger is enabled; ICSPCLK and ICSPDAT are dedicated to the debugger
bit 11
LPBOREN: Low-Power Brown-out Reset Enable bit
1 = Off – Low-power Brown-out Reset is disabled
0 = On – Low-power Brown-out Reset is enabled
bit 10
BORV: Brown-out Reset Voltage Selection bit(3)
1 = Low – Brown-out Reset voltage (VBOR), low trip point selected
0 = High – Brown-out Reset voltage (VBOR), high trip point selected
bit 9
STVREN: Stack Overflow/Underflow Reset Enable bit
1 = On – Stack overflow or underflow will cause a Reset
0 = Off – Stack overflow or underflow will not cause a Reset
bit 8
PLLEN: PLL Enable bit
1 = On – 4xPLL is enabled
0 = Off – 4xPLL is disabled
bit 7-2
Unimplemented: Read as ‘1’
bit 1-0
WRT<1:0>: Flash Memory Self-Write Protection bits
2 kW Flash Memory (PIC12F1572):
11 = Off – Write protection is off
10 = Boot – 000h to 1FFh is write-protected, 200h to 7FFh may be modified by PMCON control
01 = Half – 000h to 3FFh is write-protected, 400h to 7FFh may be modified by PMCON control
00 = All – 000h to 7FFh is write-protected, no addresses may be modified by PMCON control
1 kW Flash Memory (PIC12(L)F1571):
11 = Off – Write protection is off
10 = Boot – 000h to 0FFh is write-protected, 100h to 3FFh may be modified by PMCON control
01 = Half – 000h to 1FFh is write-protected, 200h to 3FFh may be modified by PMCON control
00 = All – 000h to 3FFh is write-protected, no addresses may be modified by PMCON control
Note 1:
2:
3:
This bit cannot be programmed to ‘0’ when programming mode is entered via LVP.
The DEBUG bit in Configuration Words is managed automatically by device development tools, including
debuggers and programmers. For normal device operation, this bit should be maintained as a ‘1’.
See VBOR parameter for specific trip point voltages.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 43
PIC12(L)F1571/2
4.3
Code Protection
Code protection allows the device to be protected from
unauthorized access. Internal access to the program
memory is unaffected by any code protection setting.
4.3.1
PROGRAM MEMORY PROTECTION
The entire program memory space is protected from
external reads and writes by the CP bit in the
Configuration Words. When CP = 0, external reads and
writes of program memory are inhibited and a read will
return all ‘0’s. The CPU can continue to read program
memory, regardless of the protection bit settings.
Writing the program memory is dependent upon the
write protection setting. See Section 4.4 “Write
Protection” for more information.
4.4
Write Protection
Write protection allows the device to be protected from
unintended self-writes. Applications, such as bootloader software, can be protected while allowing other
regions of the program memory to be modified.
4.5
User ID
Four memory locations (8000h-8003h) are designated as
ID locations where the user can store checksum or other
code identification numbers. These locations are
readable and writable during normal execution. See
Section 10.4 “User ID, Device ID and Configuration
Word Access” for more information on accessing
these memory locations. For more information on
checksum calculation, see the “PIC12(L)F1571/2
Memory Programming Specification” (DS40001713).
4.6
Device ID and Revision ID
The 14-bit Device ID word is located at 8006h and the
14-bit Revision ID is located at 8005h. These locations
are read-only and cannot be erased or modified. See
Section 10.4 “User ID, Device ID and Configuration
Word Access” for more information on accessing
these memory locations.
Development tools, such as device programmers and
debuggers, may be used to read the Device ID and
Revision ID.
The WRT<1:0> bits in the Configuration Words define
the size of the program memory block that is protected.
DS40001723D-page 44
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PIC12(L)F1571/2
4.7
Register Definitions: Device ID
DEVICEID: DEVICE ID REGISTER(1)
REGISTER 4-3:
R
R
R
R
R
R
DEV<13:8>
bit 13
R
R
bit 8
R
R
R
R
R
R
DEV<7:0>
bit 7
bit 0
Legend:
R = Readable bit
‘0’ = Bit is cleared
bit 13-0
x = Bit is unknown
‘1’ = Bit is set
DEV<13:0>: Device ID bits
Refer to Table 4-1 to determine what these bits will read on which device. A value of 3FFFh is invalid.
Note 1:
This location cannot be written.
REVISIONID: REVISION ID REGISTER(1)
REGISTER 4-4:
R
R
R
R
R
R
REV<13:8>
bit 13
R
R
bit 8
R
R
R
R
R
R
REV<7:0>
bit 7
bit 0
Legend:
R = Readable bit
‘0’ = Bit is cleared
bit 13-0
‘1’ = Bit is set
x = Bit is unknown
REV<13:0>: Revision ID bits
These bits are used to identify the device revision.
Note 1:
This location cannot be written.
TABLE 4-1:
DEVICE ID VALUES
DEVICE
Device ID
Revision ID
PIC12F1571
3051h
2xxxh
PIC12LF1571
3053h
2xxxh
PIC12F1572
3050h
2xxxh
PIC12LF1572
3052h
2xxxh
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DS40001723D-page 45
PIC12(L)F1571/2
NOTES:
DS40001723D-page 46
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PIC12(L)F1571/2
5.0
OSCILLATOR MODULE
The oscillator module can be configured in one of the
following clock modes:
5.1
Overview
1.
The oscillator module has a wide variety of clock
sources and selection features that allow it to be used in
a wide range of applications, while maximizing performance and minimizing power consumption. Figure 5-1
illustrates a block diagram of the oscillator module.
Clock sources can be supplied from external oscillators,
quartz crystal resonators, ceramic resonators and
Resistor-Capacitor (RC) circuits. In addition, the system
clock source can be supplied from one of two internal
oscillators and PLL circuits, with a choice of speeds
selectable via software. Additional clock features
include:
• Selectable system clock source between external
or internal sources via software
• Oscillator Start-up Timer (OST) ensures stability
of crystal oscillator sources
 2013-2015 Microchip Technology Inc.
2.
3.
4.
ECL – External Clock Low-Power mode
(0 MHz to 0.5 MHz)
ECM – External Clock Medium Power mode
(0.5 MHz to 4 MHz)
ECH – External Clock High-Power mode
(4 MHz to 32 MHz)
INTOSC – Internal Oscillator (31 kHz to 32 MHz)
Clock Source modes are selected by the FOSC<1:0>
bits in the Configuration Words. The FOSC bits determine the type of oscillator that will be used when the
device is first powered.
The ECH, ECM, and ECL Clock modes rely on an
external logic level signal as the device clock source.
The INTOSC internal oscillator block produces low,
medium and high-frequency clock sources, designated
as LFINTOSC, MFINTOSC and HFINTOSC (see
Internal Oscillator Block, Figure 5-1). A wide selection
of device clock frequencies may be derived from these
three clock sources.
DS40001723D-page 47
PIC12(L)F1571/2
SIMPLIFIED PIC® MCU CLOCK SOURCE BLOCK DIAGRAM
FIGURE 5-1:
Rev. 10-000155A
10/11/2013
FOSC<1:0>
01
Reserved
2
CLKIN
0
INTOSC
PLLEN
FOSC(1)
00
1
4x PLL(2)
Sleep
to CPU and
Peripherals
1x
SPLLEN
2
16 MHz
SCS<1:0>
8 MHz
4 MHz
500 kHz
Oscillator
MFINTOSC(1)
2 MHz
Prescaler
HFPLL
16 MHz
HFINTOSC(1)
1 MHz
*500 kHz
*250 kHz
*125 kHz
62.5 kHz
*31.25 kHz
*31 kHz
Internal Oscillator
Block
4
IRCF<3:0>
31 kHz
Oscillator
600 kHz
Oscillator
LFINTOSC(1)
FRC(1)
to WDT, PWRT, and
other Peripherals
to Peripherals
to ADC and
other Peripherals
* Available with more than one IRCF selection
Note 1:
2:
3:
See Section 5.2 “Clock Source Types”.
ST Buffer is high-speed type when using T1CKI.
If FOSC<1:0> = 00, 4x PLL can only be used if IRCF<3:0> = 1110.
DS40001723D-page 48
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PIC12(L)F1571/2
5.2
Clock Source Types
Clock sources can be classified as external or internal.
External clock sources rely on external circuitry for the
clock source to function.
Internal clock sources are contained within the
oscillator module. The internal oscillator block has two
internal oscillators and a dedicated Phase-Locked
Loop (HFPLL) that are used to generate three internal
system clock sources: the 16 MHz High-Frequency
Internal Oscillator (HFINTOSC), 500 kHz Medium
Frequency Internal Oscillator (MFINTOSC) and the
31 kHz Low-Frequency Internal Oscillator (LFINTOSC).
The system clock can be selected between external or
internal clock sources via the System Clock Select
(SCS<1:0>) bits in the OSCCON register. See
Section 5.3 “Clock Switching” for additional
information.
5.2.1
EXTERNAL CLOCK SOURCES
An external clock source can be used as the device
system clock by performing one of the following
actions:
• Program the FOSC<1:0> bits in the Configuration
Words to select an external clock source that will
be used as the default system clock upon a
device Reset.
• Write the SCS<1:0> bits in the OSCCON register
to switch the system clock source to:
- Timer1 oscillator during run time, or
- An external clock source determined by the
value of the FOSCx bits.
See Section 5.3 “Clock Switching” for more
information.
 2013-2015 Microchip Technology Inc.
5.2.1.1
EC Mode
The External Clock (EC) mode allows an externally
generated logic level signal to be the system clock
source. When operating in this mode, an external clock
source is connected to the CLKIN input. CLKOUT is
available for general purpose I/Os or CLKOUT.
Figure 5-2 shows the pin connections for EC mode.
EC mode has three power modes to select from through
the FOSCx bits in the Configuration Words:
• ECH – High power, 4-20 MHz
• ECM – Medium power, 0.5-4 MHz
• ECL – Low power, 0-0.5 MHz
The Oscillator Start-up Timer (OST) is disabled when
EC mode is selected. Therefore, there is no delay in
operation after a Power-on Reset (POR) or wake-up
from Sleep. Because the PIC® MCU design is fully
static, stopping the external clock input will have the
effect of halting the device while leaving all data intact.
Upon restarting the external clock, the device will
resume operation as if no time had elapsed.
FIGURE 5-2:
Clock from
Ext. System
EXTERNAL CLOCK (EC)
MODE OPERATION
CLKIN
PIC® MCU
FOSC/4 or
I/O(1)
Note 1:
CLKOUT
Output depends upon CLKOUTEN bit of
the Configuration Words.
DS40001723D-page 49
PIC12(L)F1571/2
5.2.2
INTERNAL CLOCK SOURCES
The device may be configured to use the internal oscillator block as the system clock by performing one of the
following actions:
• Program the FOSC<1:0> bits in the Configuration
Words to select the INTOSC clock source, which
will be used as the default system clock upon a
device Reset.
• Write the SCS<1:0> bits in the OSCCON register
to switch the system clock source to the internal
oscillator during run time. See
Section 5.3 “Clock Switching”for more
information.
In INTOSC mode, CLKIN is available for general
purpose I/O. CLKOUT is available for general purpose
I/O or CLKOUT.
The function of the OSC2/CLKOUT pin is determined
by the CLKOUTEN bit in the Configuration Words.
The internal oscillator block has two independent
oscillators and a dedicated Phase-Locked Loop,
HFPLL, that can produce one of three internal system
clock sources.
1.
2.
3.
The HFINTOSC (High-Frequency Internal
Oscillator) is factory calibrated and operates at
16 MHz. The HFINTOSC source is generated
from the 500 kHz MFINTOSC source and the
dedicated Phase-Locked Loop, HFPLL. The
frequency of the HFINTOSC can be
user-adjusted via software using the OSCTUNE
register (Register 5-3).
The MFINTOSC (Medium Frequency Internal
Oscillator) is factory calibrated and operates at
500 kHz. The frequency of the MFINTOSC can
be user-adjusted via software using the
OSCTUNE register (Register 5-3).
The LFINTOSC (Low-Frequency Internal
Oscillator) is uncalibrated and operates at
31 kHz.
5.2.2.1
HFINTOSC
The High-Frequency Internal Oscillator (HFINTOSC) is
a factory calibrated 16 MHz internal clock source. The
frequency of the HFINTOSC can be altered via
software using the OSCTUNE register (Register 5-3).
The output of the HFINTOSC connects to a postscaler
and multiplexer (see Figure 5-1). One of multiple
frequencies derived from the HFINTOSC can be
selected via software using the IRCF<3:0> bits of the
OSCCON register. See Section 5.2.2.8 “Internal
Oscillator Clock Switch Timing” for more information.
The HFINTOSC is enabled by:
• Configuring the IRCF<3:0> bits of the OSCCON
register for the desired HF frequency, and
• Setting FOSC<1:0> = 00, or
• Setting the System Clock Source x (SCSx) bits of
the OSCCON register to ‘1x’.
A fast start-up oscillator allows internal circuits to power
up and stabilize before switching to HFINTOSC.
The High-Frequency Internal Oscillator Ready bit
(HFIOFR) of the OSCSTAT register indicates when the
HFINTOSC is running.
The High-Frequency Internal Oscillator Status Locked
bit (HFIOFL) of the OSCSTAT register indicates when
the HFINTOSC is running within 2% of its final value.
The High-Frequency Internal Oscillator Stable bit
(HFIOFS) of the OSCSTAT register indicates when the
HFINTOSC is running within 0.5% of its final value.
5.2.2.2
MFINTOSC
The Medium Frequency Internal Oscillator (MFINTOSC)
is a factory calibrated 500 kHz internal clock source.
The frequency of the MFINTOSC can be altered via
software using the OSCTUNE register (Register 5-3).
The output of the MFINTOSC connects to a postscaler
and multiplexer (see Figure 5-1). One of nine
frequencies derived from the MFINTOSC can be
selected via software using the IRCF<3:0> bits of the
OSCCON register. See Section 5.2.2.8 “Internal
Oscillator Clock Switch Timing” for more information.
The MFINTOSC is enabled by:
• Configuring the IRCF<3:0> bits of the OSCCON
register for the desired HF frequency, and
• Setting FOSC<1:0> = 00, or
• Setting the System Clock Source x (SCSx) bits of
the OSCCON register to ‘1x’
The Medium Frequency Internal Oscillator Ready bit
(MFIOFR) of the OSCSTAT register indicates when the
MFINTOSC is running.
DS40001723D-page 50
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PIC12(L)F1571/2
5.2.2.3
Internal Oscillator Frequency
Adjustment
The 500 kHz internal oscillator is factory calibrated.
This internal oscillator can be adjusted in software by
writing to the OSCTUNE register (Register 5-3). Since
the HFINTOSC and MFINTOSC clock sources are
derived from the 500 kHz internal oscillator, a change
in the OSCTUNE register value will apply to both.
The default value of the OSCTUNE register is ‘0’. The
value is a 6-bit two’s complement number. A value of
1Fh will provide an adjustment to the maximum
frequency. A value of 20h will provide an adjustment to
the minimum frequency.
When the OSCTUNE register is modified, the oscillator
frequency will begin shifting to the new frequency. Code
execution continues during this shift. There is no
indication that the shift has occurred.
OSCTUNE does not affect the LFINTOSC frequency.
Operation of features that depends on the LFINTOSC
clock source frequency, such as the Power-up Timer
(PWRT), Watchdog Timer (WDT) and peripherals, are
not affected by the change in frequency.
5.2.2.4
LFINTOSC
The Low-Frequency Internal Oscillator (LFINTOSC) is
an uncalibrated 31 kHz internal clock source.
The output of the LFINTOSC connects to a multiplexer
(see Figure 5-1). Select 31 kHz, via software, using
the IRCF<3:0> bits of the OSCCON register. See
Section 5.2.2.8 “Internal Oscillator Clock Switch
Timing” for more information. The LFINTOSC is also
the frequency for the Power-up Timer (PWRT),
Watchdog Timer (WDT) and Fail-Safe Clock Monitor
(FSCM).
The LFINTOSC is enabled by selecting 31 kHz
(IRCF<3:0> (OSCCON<6:3>) = 0000) as the system
clock source (SCS<1:0> (OSCCON<1:0>) = 1x) or
when any of the following are enabled:
• Configure the IRCF<3:0> bits of the OSCCON
register for the desired LF frequency, and
• Set FOSC<1:0> = 00, or
• Set the System Clock Source x (SCSx) bits of the
OSCCON register to ‘1x’
Peripherals that use the LFINTOSC are:
• Power-up Timer (PWRT)
• Watchdog Timer (WDT)
5.2.2.5
FRC
The FRC clock is an uncalibrated, nominal 600 kHz
peripheral clock source.
The FRC is automatically turned on by the peripherals
requesting the FRC clock.
The FRC clock will continue to run during Sleep.
5.2.2.6
Internal Oscillator Frequency
Selection
The system clock speed can be selected via software
using the Internal Oscillator Frequency Select bits
IRCF<3:0> of the OSCCON register.
The postscaler outputs of the 16 MHz HFINTOSC,
500 kHz MFINTOSC and 31 kHz LFINTOSC output
connect to a multiplexer (see Figure 5-1). The Internal
Oscillator Frequency Select bits, IRCF<3:0> of the
OSCCON register, select the frequency output of the
internal oscillators. One of the following frequencies
can be selected via software:
•
•
•
•
•
•
•
•
•
•
•
•
32 MHz (requires 4x PLL)
16 MHz
8 MHz
4 MHz
2 MHz
1 MHz
500 kHz (default after Reset)
250 kHz
125 kHz
62.5 kHz
31.25 kHz
31 kHz (LFINTOSC)
Note:
Following any Reset, the IRCF<3:0> bits
of the OSCCON register are set to ‘0111’
and the frequency selection is set to
500 kHz. The user can modify the IRCFx
bits to select a different frequency.
The IRCF<3:0> bits of the OSCCON register allow
duplicate selections for some frequencies. These duplicate choices can offer system design trade-offs. Lower
power consumption can be obtained when changing
oscillator sources for a given frequency. Faster transition times can be obtained between frequency changes
that use the same oscillator source.
The Low-Frequency Internal Oscillator Ready bit
(LFIOFR) of the OSCSTAT register indicates when the
LFINTOSC is running.
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DS40001723D-page 51
PIC12(L)F1571/2
5.2.2.7
32 MHz Internal Oscillator
Frequency Selection
The internal oscillator block can be used with the
4x PLL associated with the external oscillator block to
produce a 32 MHz internal system clock source. The
following settings are required to use the 32 MHz
internal clock source:
• The FOSCx bits in the Configuration Words must
be set to use the INTOSC source as the device
system clock (FOSC<1:0> = 00).
• The SCSx bits in the OSCCON register must be
cleared to use the clock determined by
FOSC<1:0> in the Configuration Words
(SCS<1:0> = 00).
• The IRCFx bits in the OSCCON register must be
set to the 8 MHz HFINTOSC to use
(IRCF<3:0> = 1110).
• The SPLLEN bit in the OSCCON register must be
set to enable the 4x PLL or the PLLEN bit of the
Configuration Words must be programmed to a
‘1’.
Note:
When using the PLLEN bit of the
Configuration Words, the 4x PLL cannot
be disabled by software and the 8 MHz
HFINTOSC option will no longer be
available.
The 4x PLL is not available for use with the internal
oscillator when the SCSx bits of the OSCCON register
are set to ‘1x’. The SCSx bits must be set to ‘00’ to use
the 4x PLL with the internal oscillator.
DS40001723D-page 52
5.2.2.8
Internal Oscillator Clock Switch
Timing
When switching between the HFINTOSC, MFINTOSC
and the LFINTOSC, the new oscillator may already be
shut down to save power (see Figure 5-3). If this is the
case, there is a delay after the IRCF<3:0> bits of the
OSCCON register are modified before the frequency
selection takes place. The OSCSTAT register will
reflect the current active status of the HFINTOSC,
MFINTOSC and LFINTOSC oscillators. The sequence
of a frequency selection is as follows:
1.
2.
3.
4.
5.
6.
7.
IRCF<3:0> bits of the OSCCON register are
modified.
If the new clock is shut down, a clock start-up
delay is started.
Clock switch circuitry waits for a falling edge of
the current clock.
The current clock is held low and the clock
switch circuitry waits for a rising edge in the new
clock.
The new clock is now active.
The OSCSTAT register is updated as required.
Clock switch is complete.
See Figure 5-3 for more details.
If the internal oscillator speed is switched between two
clocks of the same source, there is no start-up delay
before the new frequency is selected. Clock switching
time delays are shown in Table 5-1.
Start-up delay specifications are located in the
oscillator tables of Section 26.0 “Electrical
Specifications”.
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
FIGURE 5-3:
INTERNAL OSCILLATOR SWITCH TIMING
HFINTOSC/
MFINTOSC
LFINTOSC (WDT disabled)
HFINTOSC/
MFINTOSC
Oscillator Delay(1)
2-Cycle Sync
Running
LFINTOSC
0
IRCF<3:0>
=0
System Clock
LFINTOSC (WDT enabled)
HFINTOSC/
MFINTOSC
HFINTOSC/
MFINTOSC
2-Cycle Sync
Running
LFINTOSC
0
IRCF <3:0>
=0
System Clock
LFINTOSC
HFINTOSC/MFINTOSC
LFINTOSC Turns Off unless WDT is Enabled
LFINTOSC
Oscillator
Delay(1)
HFINTOSC/
MFINTOSC
IRCF <3:0>
=0
2-Cycle Sync
Running
0
System Clock
Note 1:
See Table 5-1 (Oscillator Switching Delays) for more information.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 53
PIC12(L)F1571/2
5.3
Clock Switching
5.4
The system clock source can be switched between
external and internal clock sources via software using
the System Clock Select (SCSx) bits of the OSCCON
register. The following clock sources can be selected
using the SCSx bits:
When clock switching from an old clock to a new clock
is requested, just prior to entering Sleep mode, it is
necessary to confirm that the switch is complete before
the SLEEP instruction is executed. Failure to do so may
result in an incomplete switch and consequential loss of
the system clock altogether. Clock switching is
confirmed by monitoring the clock status bits in the
OSCSTAT register. Switch confirmation can be accomplished by sensing that the ready bit for the new clock is
set or the ready bit for the old clock is cleared. For
example, when switching between the internal oscillator
with the PLL and the internal oscillator without the PLL,
monitor the PLLR bit. When PLLR is set, the switch to
32 MHz operation is complete. Conversely, when PLLR
is cleared, the switch from 32 MHz operation to the
selected internal clock is complete.
• Default system oscillator determined by FOSCx
bits in the Configuration Words
• Timer1 32 kHz crystal oscillator
• Internal Oscillator Block (INTOSC)
5.3.1
Clock Switching Before Sleep
SYSTEM CLOCK SELECT (SCSx)
BITS
The System Clock Select (SCSx) bits of the OSCCON
register select the system clock source that is used for
the CPU and peripherals.
• When the SCSx bits of the OSCCON register = 00,
the system clock source is determined by the value
of the FOSC<1:0> bits in the Configuration Words.
• When the SCSx bits of the OSCCON register = 01,
the system clock source is the Timer1 oscillator.
• When the SCSx bits of the OSCCON register = 1x,
the system clock source is chosen by the internal
oscillator frequency selected by the IRCF<3:0> bits
of the OSCCON register. After a Reset, the SCSx
bits of the OSCCON register are always cleared.
Note:
Any automatic clock switch does not
update the SCSx bits of the OSCCON
register. The user can monitor the OSTS
bit of the OSCSTAT register to determine
the current system clock source.
When switching between clock sources, a delay is
required to allow the new clock to stabilize. These
oscillator delays are shown in Table 5-1.
TABLE 5-1:
OSCILLATOR SWITCHING DELAYS
Switch From
Switch To
Frequency
Oscillator Delay
Sleep/POR
LFINTOSC(1)
MFINTOSC(1)
HFINTOSC(1)
31 kHz
31.25 kHz-500 kHz
31.25 kHz-16 MHz
Sleep/POR
EC(1)
DC – 32 MHz
2 cycles
LFINTOSC
EC(1)
DC – 32 MHz
1 cycle of each
Any Clock Source
MFINTOSC(1)
HFINTOSC(1)
31.25 kHz-500 kHz
31.25 kHz-16 MHz
2 s (approx.)
Any Clock Source
LFINTOSC(1)
31 kHz
1 cycle of each
PLL Inactive
PLL Active
16-32 MHz
2 ms (approx.)
Note 1:
2:
Oscillator Warm-up Delay (TWARM)(2)
PLL inactive.
See Section 26.0 “Electrical Specifications”.
DS40001723D-page 54
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
5.5
Register Definitions: Oscillator Control
REGISTER 5-1:
R/W-0/0
OSCCON: OSCILLATOR CONTROL REGISTER
R/W-0/0
R/W-1/1
SPLLEN
R/W-1/1
R/W-1/1
U-0
IRCF<3:0>
R/W-0/0
—
R/W-0/0
SCS<1:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
SPLLEN: Software PLL Enable bit
If PLLEN in Configuration Words = 1:
SPLLEN bit is ignored. 4x PLL is always enabled (subject to oscillator requirements).
If PLLEN in Configuration Words = 0:
1 = 4x PLL Is enabled
0 = 4x PLL is disabled
bit 6-3
IRCF<3:0>: Internal Oscillator Frequency Select bits
1111 = 16 MHz HF
1110 = 8 MHz or 32 MHz HF (see Section 5.2.2.1 “HFINTOSC”)
1101 = 4 MHz HF
1100 = 2 MHz HF
1011 = 1 MHz HF
1010 = 500 kHz HF(1)
1001 = 250 kHz HF(1)
1000 = 125 kHz HF(1)
0111 = 500 kHz MF (default upon Reset)
0110 = 250 kHz MF
0101 = 125 kHz MF
0100 = 62.5 kHz MF
0011 = 31.25 kHz HF(1)
0010 = 31.25 kHz MF
000x = 31 kHz LF
bit 2
Unimplemented: Read as ‘0’
bit 1-0
SCS<1:0>: System Clock Select bits
1x = Internal oscillator block
01 = Timer1 oscillator
00 = Clock determined by FOSC<1:0> in Configuration Words
Note 1:
Duplicate frequency derived from HFINTOSC.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 55
PIC12(L)F1571/2
REGISTER 5-2:
OSCSTAT: OSCILLATOR STATUS REGISTER
U-0
R-0/q
R-q/q
R-0/q
R-0/q
R-q/q
R-0/q
R-0/q
—
PLLR
OSTS
HFIOFR
HFIOFL
MFIOFR
LFIOFR
HFIOFS
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
q = Conditional bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
Unimplemented: Read as ‘0’
bit 6
PLLR 4x PLL Ready bit
1 = 4x PLL is ready
0 = 4x PLL is not ready
bit 5
OSTS: Oscillator Start-up Timer Status bit
1 = Running from the clock defined by the FOSC<1:0> bits of the Configuration Words
0 = Running from an internal oscillator (FOSC<1:0> = 00)
bit 4
HFIOFR: High-Frequency Internal Oscillator Ready bit
1 = HFINTOSC is ready
0 = HFINTOSC is not ready
bit 3
HFIOFL: High-Frequency Internal Oscillator Locked bit
1 = HFINTOSC is at least 2% accurate
0 = HFINTOSC is not 2% accurate
bit 2
MFIOFR: Medium Frequency Internal Oscillator Ready bit
1 = MFINTOSC is ready
0 = MFINTOSC is not ready
bit 1
LFIOFR: Low-Frequency Internal Oscillator Ready bit
1 = LFINTOSC is ready
0 = LFINTOSC is not ready
bit 0
HFIOFS: High-Frequency Internal Oscillator Stable bit
1 = HFINTOSC is at least 0.5% accurate
0 = HFINTOSC is not 0.5% accurate
DS40001723D-page 56
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
REGISTER 5-3:
OSCTUNE: OSCILLATOR TUNING REGISTER
U-0
U-0
—
—
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
TUN<5:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-6
Unimplemented: Read as ‘0’
bit 5-0
TUN<5:0>: Frequency Tuning bits
100000 = Minimum frequency
•
•
•
111111 =
000000 = Oscillator module is running at the factory-calibrated frequency
000001 =
•
•
•
011110 =
011111 = Maximum frequency
TABLE 5-2:
SUMMARY OF REGISTERS ASSOCIATED WITH CLOCK SOURCES
Name
Bit 7
Bit 6
Bit 5
OSTS
OSCCON
SPLLEN
OSCSTAT
—
PLLR
OSCTUNE
—
—
T1CON
TMR1CS<1:0>
Bit 4
Bit 3
Bit 2
HFIOFL
MFIOFR
—
IRCF<3:0>
HFIOFR
Bit 1
Bit 0
SCS<1:0>
55
LFIOFR
HFIOFS
56
—
TMR1ON
167
TUN<5:0>
T1CKPS<1:0>
—
Register
on Page
57
T1SYNC
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used by clock sources.
TABLE 5-3:
Name
CONFIG1
SUMMARY OF CONFIGURATION WORD WITH CLOCK SOURCES
Bits Bit -/7
Bit -/6
Bit 13/5
Bit 12/4
Bit 11/3
—
CLKOUTEN
13:8
—
—
—
7:0
CP
MCLRE
PWRTE
WDTE<1:0>
Bit 10/2
Bit 9/1
Bit 8/0
BOREN<1:0>
—
—
FOSC<1:0>
Register
on Page
42
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used by clock sources.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 57
PIC12(L)F1571/2
NOTES:
DS40001723D-page 58
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
6.0
RESETS
There are multiple ways to reset this device:
•
•
•
•
•
•
•
•
•
Power-on Reset (POR)
Brown-out Reset (BOR)
Low-Power Brown-out Reset (LPBOR)
MCLR Reset
WDT Reset
RESET instruction
Stack Overflow
Stack Underflow
Programming mode exit
FIGURE 6-1:
To allow VDD to stabilize, an optional Power-up Timer
can be enabled to extend the Reset time after a BOR
or POR event.
A simplified block diagram of the On-Chip Reset Circuit
is shown in Figure 6-1.
SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT
Rev. 10-000006A
8/14/2013
ICSP™ Programming Mode Exit
RESET Instruction
Stack Underflow
Stack Overlfow
MCLRE
VPP/MCLR
Sleep
WDT
Time-out
Device
Reset
Power-on
Reset
VDD
BOR
Active(1)
Brown-out
Reset
LPBOR
Reset
Note 1:
R
LFINTOSC
Power-up
Timer
PWRTE
See Table 6-1 for BOR active conditions.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 59
PIC12(L)F1571/2
6.1
Power-on Reset (POR)
6.2
Brown-out Reset (BOR)
The POR circuit holds the device in Reset until VDD has
reached an acceptable level for minimum operation.
Slow rising VDD, fast operating speeds or analog
performance may require greater than minimum VDD.
The PWRT, BOR or MCLR features can be used to
extend the start-up period until all device operation
conditions have been met.
The BOR circuit holds the device in Reset when VDD
reaches a selectable minimum level. Between the
POR and BOR, complete voltage range coverage for
execution protection can be implemented.
6.1.1
•
•
•
•
POWER-UP TIMER (PWRT)
The Power-up Timer provides a nominal 64 ms
time-out on a POR or Brown-out Reset.
The device is held in Reset as long as PWRT is active.
The PWRT delay allows additional time for the VDD to
rise to an acceptable level. The Power-up Timer is
enabled by clearing the PWRTE bit in the Configuration
Words.
The Power-up Timer starts after the release of the POR
and BOR.
For additional information, refer to Application Note
AN607, “Power-up Trouble Shooting” (DS00000607).
TABLE 6-1:
The Brown-out Reset module has four operating
modes controlled by the BOREN<1:0> bits in the
Configuration Words. The four operating modes are:
BOR is always on
BOR is off when in Sleep
BOR is controlled by software
BOR is always off
Refer to Table 6-1 for more information.
The Brown-out Reset voltage level is selectable by
configuring the BORV bit in the Configuration Words.
A VDD noise rejection filter prevents the BOR from triggering on small events. If VDD falls below VBOR for a
duration greater than parameter, TBORDC, the device
will reset. See Figure 6-2 for more information.
BOR OPERATING MODES
BOREN<1:0>
SBOREN
Device Mode
BOR Mode
Instruction Execution upon:
Release of POR or Wake-up from Sleep
11
X
X
Active
Waits for BOR ready(1)
(BORRDY = 1)
10
X
Awake
Active
Sleep
Disabled
1
X
Active
0
X
Disabled
X
X
Disabled
01
00
Note 1:
Waits for BOR ready
(BORRDY = 1)
Waits for BOR ready(1)
(BORRDY = 1)
Begins immediately
(BORRDY = x)
In these specific cases, “release of POR” and “wake-up from Sleep”, there is no delay in start-up. The BOR
ready flag (BORRDY = 1) will be set before the CPU is ready to execute instructions because the BOR
circuit is forced on by the BOREN<1:0> bits.
DS40001723D-page 60
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
6.2.1
BOR IS ALWAYS ON
BOR protection is not active during Sleep. The device
wake-up will be delayed until the BOR is ready.
When the BORENx bits of the Configuration Words are
programmed to ‘11’, the BOR is always on. The device
start-up will be delayed until the BOR is ready and VDD
is higher than the BOR threshold.
6.2.3
When the BORENx bits of the Configuration Words
are programmed to ‘01’, the BOR is controlled by the
SBOREN bit of the BORCON register. The device
start-up is not delayed by the BOR ready condition or
the VDD level.
BOR protection is active during Sleep. The BOR does
not delay wake-up from Sleep.
6.2.2
BOR IS OFF IN SLEEP
BOR protection begins as soon as the BOR circuit is
ready. The status of the BOR circuit is reflected in the
BORRDY bit of the BORCON register.
When the BORENx bits of the Configuration Words are
programmed to ‘10’, the BOR is on, except in Sleep.
The device start-up will be delayed until the BOR is
ready and VDD is higher than the BOR threshold.
FIGURE 6-2:
BOR protection is unchanged by Sleep.
BROWN-OUT SITUATIONS
VDD
Internal
Reset
VBOR
TPWRT(1)
VDD
Internal
Reset
VBOR
< TPWRT
TPWRT(1)
VDD
Internal
Reset
Note 1:
BOR CONTROLLED BY SOFTWARE
VBOR
TPWRT(1)
TPWRT delay only if PWRTE bit is programmed to ‘0’.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 61
PIC12(L)F1571/2
6.3
Register Definitions: BOR Control
REGISTER 6-1:
BORCON: BROWN-OUT RESET CONTROL REGISTER
R/W-1/u
R/W-0/u
U-0
U-0
U-0
U-0
U-0
R-q/u
SBOREN
BORFS(1)
—
—
—
—
—
BORRDY
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
q = Value depends on condition
bit 7
SBOREN: Software Brown-out Reset Enable bit
If BOREN<1:0> in Configuration Words = 01:
1 = BOR is enabled
0 = BOR is disabled
If BOREN <1:0> in Configuration Words  01:
SBOREN is read/write, but has no effect on the BOR.
bit 6
BORFS: Brown-out Reset Fast Start bit(1)
If BOREN <1:0> = 10 (Disabled in Sleep) or BOREN<1:0> = 01 (Under software control):
1 = Band gap is forced on always (covers Sleep/wake-up/operating cases)
0 = Band gap operates normally and may turn off
If BOREN<1:0> = 11 (Always On) or BOREN<1:0> = 00 (Always Off):
BORFS is read/write, but has no effect on the BOR.
bit 5-1
Unimplemented: Read as ‘0’
bit 0
BORRDY: Brown-out Reset Circuit Ready Status bit
1 = The Brown-out Reset circuit is active
0 = The Brown-out Reset circuit is inactive
Note 1:
BOREN<1:0> bits are located in the Configuration Words.
DS40001723D-page 62
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
6.4
Low-Power Brown-out Reset
(LPBOR)
The Low-Power Brown-out Reset (LPBOR) operates
like the BOR to detect low-voltage conditions on the
VDD pin. When too low of a voltage is detected, the
device is held in Reset. When this occurs, a register bit
(BOR) is changed to indicate that a BOR Reset has
occurred. The BOR bit in PCON is used for both BOR
and the LPBOR. Refer to Register 6-2.
The LPBOR Voltage Threshold (VLPBOR) has a wider
tolerance than the BOR (VBOR), but requires much
less current (LPBOR current) to operate. The LPBOR
is intended for use when the BOR is configured as disabled (BOREN<1:0> = 00) or disabled in Sleep mode
(BOREN<1:0> = 10).
Refer to Figure 6-1 to see how the LPBOR interacts
with other modules.
6.4.1
ENABLING LPBOR
The LPBOR is controlled by the LPBOR bit of the
Configuration Words. When the device is erased, the
LPBOR module defaults to disabled.
The MCLR is an optional external input that can reset
the device. The MCLR function is controlled by the
MCLRE and LVP bits of the Configuration Words
(Table 6-2).
TABLE 6-2:
MCLR CONFIGURATION
MCLRE
LVP
MCLR
0
0
Disabled
1
0
Enabled
x
1
Enabled
6.5.1
MCLR ENABLED
When MCLR is enabled and the pin is held low, the
device is held in Reset. The MCLR pin is connected to
VDD through an internal weak pull-up.
The device has a noise filter in the MCLR Reset path.
The filter will detect and ignore small pulses.
Note:
6.5.2
Watchdog Timer (WDT) Reset
The Watchdog Timer generates a Reset if the firmware
does not issue a CLRWDT instruction within the
time-out period. The TO and PD bits in the STATUS
register are changed to indicate the WDT Reset. See
Section 9.0 “Watchdog Timer (WDT)” for more
information.
6.7
RESET Instruction
A RESET instruction will cause a device Reset. The RI
bit in the PCON register will be set to ‘0’. See Table 6-4
for default conditions after a RESET instruction has
occurred.
6.8
Stack Overflow/Underflow Reset
The device can reset when the Stack overflows or
underflows. The STKOVF or STKUNF bits of the PCON
register indicate the Reset condition. These Resets are
enabled by setting the STVREN bit in the Configuration
Words. See Section 3.5.2 “Overflow/Underflow
Reset” for more information.
6.9
MCLR
6.5
6.6
A Reset does not drive the MCLR pin low.
MCLR DISABLED
When MCLR is disabled, the pin functions as a general
purpose input and the internal weak pull-up is under software control. See Section 11.3 “PORTA Registers” for
more information.
 2013-2015 Microchip Technology Inc.
Programming Mode Exit
Upon exit of Programming mode, the device will
behave as if a POR had just occurred.
6.10
Power-up Timer
The Power-up Timer optionally delays device execution
after a BOR or POR event. This timer is typically used to
allow VDD to stabilize before allowing the device to start
running.
The Power-up Timer is controlled by the PWRTE bit of
the Configuration Words.
6.11
Start-up Sequence
Upon the release of a POR or BOR, the following must
occur before the device will begin executing:
1.
2.
Power-up Timer runs to completion (if enabled).
MCLR must be released (if enabled).
The total time-out will vary based on oscillator
configuration and Power-up Timer configuration. See
Section 5.0 “Oscillator Module” for more information.
The Power-up Timer runs independently of a MCLR
Reset. If MCLR is kept low long enough, the Power-up
Timer will expire. Upon bringing MCLR high, the device
will begin execution after 10 FOSC cycles (see
Figure 6-3). This is useful for testing purposes or to
synchronize more than one device operating in parallel.
DS40001723D-page 63
PIC12(L)F1571/2
FIGURE 6-3:
RESET START-UP SEQUENCE
Rev. 10-000032A
7/30/2013
VDD
Internal POR
TPWRT
Power-up Timer
MCLR
Internal RESET
Int. Oscillator
FOSC
Begin Execution
code execution (1)
Internal Oscillator, PWRTEN = 0
code execution (1)
Internal Oscillator, PWRTEN = 1
VDD
Internal POR
TPWRT
Power-up Timer
MCLR
Internal RESET
Ext. Clock (EC)
FOSC
Begin Execution
code execution (1)
External Clock (EC modes), PWRTEN = 0
code execution (1)
External Clock (EC modes), PWRTEN = 1
VDD
Internal POR
TPWRT
Power-up Timer
MCLR
Internal RESET
Osc Start-Up Timer
TOST
TOST
Ext. Oscillator
FOSC
Begin Execution
code
execution (1)
External Oscillators , PWRTEN = 0, IESO = 0
code
execution (1)
External Oscillators , PWRTEN = 1, IESO = 0
VDD
Internal POR
TPWRT
Power-up Timer
MCLR
Internal RESET
Osc Start-Up Timer
TOST
TOST
Ext. Oscillator
Int. Oscillator
FOSC
Begin Execution
code execution (1)
External Oscillators , PWRTEN = 0, IESO = 1
Note 1:
code execution (1)
External Oscillators , PWRTEN = 1, IESO = 1
Code execution begins 10 FOSC cycles after the FOSC clock is released.
DS40001723D-page 64
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
6.12
Determining the Cause of a Reset
Upon any Reset, multiple bits in the STATUS and
PCON registers are updated to indicate the cause of
the Reset. Table 6-3 and Table 6-4 show the Reset
conditions of these registers.
TABLE 6-3:
RESET STATUS BITS AND THEIR SIGNIFICANCE
STKOVF STKUNF RWDT
RMCLR
RI
POR
BOR
TO
PD
Condition
0
0
1
1
1
0
x
1
1
Power-on Reset
0
0
1
1
1
0
x
0
x
Illegal, TO is Set on POR
0
0
1
1
1
0
x
x
0
Illegal, PD is Set on POR
0
0
u
1
1
u
0
1
1
Brown-out Reset
u
u
0
u
u
u
u
0
u
WDT Reset
u
u
u
u
u
u
u
0
0
WDT Wake-up from Sleep
u
u
u
u
u
u
u
1
0
Interrupt Wake-up from Sleep
u
u
u
0
u
u
u
u
u
MCLR Reset during Normal Operation
u
u
u
0
u
u
u
1
0
MCLR Reset during Sleep
u
u
u
u
0
u
u
u
u
RESET Instruction Executed
1
u
u
u
u
u
u
u
u
Stack Overflow Reset (STVREN = 1)
u
1
u
u
u
u
u
u
u
Stack Underflow Reset (STVREN = 1)
TABLE 6-4:
RESET CONDITION FOR SPECIAL REGISTERS
Program
Counter
STATUS
Register
PCON
Register
Power-on Reset
0000h
---1 1000
00-- 110x
MCLR Reset during normal operation
0000h
---u uuuu
uu-- 0uuu
MCLR Reset during Sleep
0000h
---1 0uuu
uu-- 0uuu
WDT Reset
0000h
---0 uuuu
uu-- uuuu
WDT Wake-up from Sleep
PC + 1
---0 0uuu
uu-- uuuu
Condition
Brown-out Reset
0000h
---1 1uuu
00-- 11u0
PC + 1(1)
---1 0uuu
uu-- uuuu
RESET Instruction Executed
0000h
---u uuuu
uu-- u0uu
Stack Overflow Reset (STVREN = 1)
0000h
---u uuuu
1u-- uuuu
Stack Underflow Reset (STVREN = 1)
0000h
---u uuuu
u1-- uuuu
Interrupt Wake-up from Sleep
Legend: u = unchanged; x = unknown; - = unimplemented bit, reads as ‘0’.
Note 1: When the wake-up is due to an interrupt and the Global Interrupt Enable bit (GIE) is set, the return address
is pushed on the stack and the PC is loaded with the interrupt vector (0004h) after execution of PC + 1.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 65
PIC12(L)F1571/2
6.13
Power Control (PCON) Register
The Power Control (PCON) register contains flag bits
to differentiate between a:
•
•
•
•
•
•
•
Power-on Reset (POR)
Brown-out Reset (BOR)
RESET Instruction Reset (RI)
MCLR Reset (RMCLR)
Watchdog Timer Reset (RWDT)
Stack Underflow Reset (STKUNF)
Stack Overflow Reset (STKOVF)
The PCON register bits are shown in Register 6-2.
6.14
Register Definitions: Power Control
REGISTER 6-2:
PCON: POWER CONTROL REGISTER
R/W/HS-0/q R/W/HS-0/q
STKOVF
STKUNF
U-0
R/W/HC-1/q
R/W/HC-1/q
R/W/HC-1/q
R/W/HC-q/u
R/W/HC-q/u
—
RWDT
RMCLR
RI
POR
BOR
bit 7
bit 0
Legend:
HC = Hardware Clearable bit
HS = Hardware Settable bit
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
q = Value depends on condition
bit 7
STKOVF: Stack Overflow Reset Flag bit
1 = A Stack Overflow Reset occurred
0 = A Stack Overflow Reset has not occurred or is cleared by firmware
bit 6
STKUNF: Stack Underflow Reset Flag bit
1 = A Stack Underflow Reset occurred
0 = A Stack Underflow Reset has not occurred or is cleared by firmware
bit 5
Unimplemented: Read as ‘0’
bit 4
RWDT: Watchdog Timer Reset Flag bit
1 = A Watchdog Timer Reset has not occurred or is set by firmware
0 = A Watchdog Timer Reset has occurred (cleared by hardware)
bit 3
RMCLR: MCLR Reset Flag bit
1 = A MCLR Reset has not occurred or is set by firmware
0 = A MCLR Reset has occurred (cleared by hardware)
bit 2
RI: RESET Instruction Flag bit
1 = A RESET instruction has not been executed or set by firmware
0 = A RESET instruction has been executed (cleared by hardware)
bit 1
POR: Power-on Reset Status bit
1 = No Power-on Reset occurred
0 = A Power-on Reset occurred (must be set in software after a Power-on Reset occurs)
bit 0
BOR: Brown-out Reset Status bit
1 = No Brown-out Reset occurred
0 = A Brown-out Reset occurred (must be set in software after a Power-on Reset or Brown-out Reset occurs)
DS40001723D-page 66
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PIC12(L)F1571/2
TABLE 6-5:
SUMMARY OF REGISTERS ASSOCIATED WITH RESETS
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Register
on Page
BORCON
SBOREN
BORFS
—
—
—
—
—
BORRDY
62
PCON
STKOVF
STKUNF
—
RWDT
RMCLR
RI
POR
BOR
66
STATUS
—
—
—
TO
PD
Z
DC
WDTCON
—
—
WDTPS<4:0>
C
19
SWDTEN
89
Legend: — = unimplemented bit, reads as ‘0’. Shaded cells are not used by Resets.
Note 1: Other (non Power-up) Resets include MCLR Reset and Watchdog Timer Reset during normal operation.
TABLE 6-6:
Name
CONFIG1
CONFIG2
Bits
SUMMARY OF CONFIGURATION WORD WITH RESETS
Bit -/7
Bit -/6
Bit 13/5
Bit 12/4
Bit 11/3
—
—
—
CLKOUTEN
Bit 10/2
13:8
—
7:0
CP
13:8
—
—
LVP
DEBUG
LPBOR
BORV
7:0
—
—
—
—
—
—
MCLRE PWRTE
WDTE<1:0>
Bit 9/1
BOREN<1:0>
—
Bit 8/0
—
FOSC<1:0>
STVREN
PLLEN
WRT<1:0>
Register
on Page
42
43
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used by Resets.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 67
PIC12(L)F1571/2
NOTES:
DS40001723D-page 68
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
7.0
INTERRUPTS
Many peripherals produce interrupts. Refer to the
corresponding chapters for details.
The interrupt feature allows certain events to preempt
normal program flow. Firmware is used to determine
the source of the interrupt and act accordingly. Some
interrupts can be configured to wake the MCU from
Sleep mode.
A block diagram of the interrupt logic is shown in
Figure 7-1.
This chapter contains the following information for
interrupts:
•
•
•
•
•
Operation
Interrupt Latency
Interrupts during Sleep
INT Pin
Automatic Context Saving
FIGURE 7-1:
INTERRUPT LOGIC
Rev. 10-000010A
1/13/2014
TMR0IF
TMR0IE
Peripheral Interrupts
(TMR1IF) PIR1<0>
(TMR1IE) PIE1<0>
Wake-up
(If in Sleep mode)
INTF
INTE
IOCIF
IOCIE
Interrupt
to CPU
PEIE
PIRn<7>
PIEn<7>
 2013-2015 Microchip Technology Inc.
GIE
DS40001723D-page 69
PIC12(L)F1571/2
7.1
Operation
Interrupts are disabled upon any device Reset. They
are enabled by setting the following bits:
• GIE bit of the INTCON register
• Interrupt enable bit(s) for the specific interrupt
event(s)
• PEIE bit of the INTCON register (if the interrupt
enable bit of the interrupt event is contained in the
PIE1, PIE2 and PIE3 registers)
The RETFIE instruction exits the ISR by popping the
previous address from the stack, restoring the saved
context from the shadow registers and setting the GIE
bit.
For additional information on a specific interrupt’s
operation, refer to its peripheral chapter.
Note 1: Individual interrupt flag bits are set,
regardless of the state of any other
enable bits.
2: All interrupts will be ignored while the GIE
bit is cleared. Any interrupt occurring
while the GIE bit is clear will be serviced
when the GIE bit is set again.
The INTCON, PIR1, PIR2 and PIR3 registers record
individual interrupts via interrupt flag bits. Interrupt flag
bits will be set, regardless of the status of the GIE, PEIE
and individual interrupt enable bits.
The following events happen when an interrupt event
occurs while the GIE bit is set:
7.2
• Current prefetched instruction is flushed
• GIE bit is cleared
• Current Program Counter (PC) is pushed onto the
stack
• Critical registers are automatically saved to the
shadow registers (See “Section 7.5 “Automatic
Context Saving”.”)
• PC is loaded with the interrupt vector, 0004h
Interrupt latency is defined as the time from when the
interrupt event occurs to the time code execution at the
interrupt vector begins. The latency for synchronous
interrupts is three or four instruction cycles. For
asynchronous interrupts, the latency is three to five
instruction cycles, depending on when the interrupt
occurs. See Figure 7-2 and Figure 7-3 for more details.
Interrupt Latency
The firmware within the Interrupt Service Routine (ISR)
should determine the source of the interrupt by polling
the interrupt flag bits. The interrupt flag bits must be
cleared before exiting the ISR to avoid repeated
interrupts. Because the GIE bit is cleared, any interrupt
that occurs while executing the ISR will be recorded
through its interrupt flag, but will not cause the
processor to redirect to the interrupt vector.
DS40001723D-page 70
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
FIGURE 7-2:
INTERRUPT LATENCY
Fosc
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
CLKR
Interrupt Sampled
during Q1
Interrupt
GIE
PC
Execute
PC-1
PC
1-Cycle Instruction at PC
PC+1
0004h
0005h
NOP
NOP
Inst(0004h)
PC+1/FSR
ADDR
New PC/
PC+1
0004h
0005h
Inst(PC)
NOP
NOP
Inst(0004h)
FSR ADDR
PC+1
PC+2
0004h
0005h
INST(PC)
NOP
NOP
NOP
Inst(0004h)
Inst(0005h)
FSR ADDR
PC+1
0004h
0005h
INST(PC)
NOP
NOP
Inst(0004h)
Inst(PC)
Interrupt
GIE
PC
Execute
PC-1
PC
2-Cycle Instruction at PC
Interrupt
GIE
PC
Execute
PC-1
PC
3-Cycle Instruction at PC
Interrupt
GIE
PC
Execute
PC-1
PC
3-Cycle Instruction at PC
 2013-2015 Microchip Technology Inc.
PC+2
NOP
NOP
DS40001723D-page 71
PIC12(L)F1571/2
FIGURE 7-3:
INT PIN INTERRUPT TIMING
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
FOSC
CLKOUT
(3)
INT Pin
(1)
(1)
INTF
Interrupt Latency(2)
(4)
GIE
INSTRUCTION FLOW
PC
PC
PC + 1
PC + 1
0004h
0005h
Instruction
Fetched
Inst (PC)
Inst (PC + 1)
—
Inst (0004h)
Inst (0005h)
Instruction
Executed
Inst (PC – 1)
Inst (PC)
Forced NOP
Forced NOP
Inst (0004h)
Note 1:
2:
3:
4:
INTF flag is sampled here (every Q1).
Asynchronous interrupt latency = 3-5 TCY. Synchronous latency = 3-4 TCY, where TCY = instruction cycle time.
Latency is the same whether Inst (PC) is a single cycle or a 2-cycle instruction.
For minimum width of INT pulse, refer to AC specifications in Section 26.0 “Electrical Specifications”.
INTF is enabled to be set any time during the Q4-Q1 cycles.
DS40001723D-page 72
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PIC12(L)F1571/2
7.3
Interrupts During Sleep
Some interrupts can be used to wake from Sleep. To
wake from Sleep, the peripheral must be able to
operate without the system clock. The interrupt source
must have the appropriate Interrupt Enable bit(s) set
prior to entering Sleep.
On waking from Sleep, if the GIE bit is also set, the
processor will branch to the interrupt vector. Otherwise,
the processor will continue executing instructions after the
SLEEP instruction. The instruction directly after the SLEEP
instruction will always be executed before branching to
the ISR. Refer to Section 8.0 “Power-Down Mode
(Sleep)” for more details.
7.4
INT Pin
The INT pin can be used to generate an asynchronous
edge-triggered interrupt. This interrupt is enabled by
setting the INTE bit of the INTCON register. The
INTEDG bit of the OPTION_REG register determines on
which edge the interrupt will occur. When the INTEDG
bit is set, the rising edge will cause the interrupt. When
the INTEDG bit is clear, the falling edge will cause the
interrupt. The INTF bit of the INTCON register will be set
when a valid edge appears on the INT pin. If the GIE and
INTE bits are also set, the processor will redirect
program execution to the interrupt vector.
 2013-2015 Microchip Technology Inc.
7.5
Automatic Context Saving
Upon entering an interrupt, the return PC address is
saved on the stack. Additionally, the following registers
are automatically saved in the shadow registers:
•
•
•
•
•
W register
STATUS register (except for TO and PD)
BSR register
FSR registers
PCLATH register
Upon exiting the Interrupt Service Routine, these
registers are automatically restored. Any modifications
to these registers during the ISR will be lost. If modifications to any of these registers are desired, the
corresponding shadow register should be modified and
the value will be restored when exiting the ISR. The
shadow registers are available in Bank 31 and are
readable and writable. Depending on the user’s
application, other registers may also need to be saved.
DS40001723D-page 73
PIC12(L)F1571/2
7.6
Register Definitions: Interrupt Control
REGISTER 7-1:
INTCON: INTERRUPT CONTROL REGISTER
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R-0/0
GIE(1)
PEIE(2)
TMR0IE
INTE
IOCIE
TMR0IF
INTF
IOCIF(3)
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
GIE: Global Interrupt Enable bit(1)
1 = Enables all active interrupts
0 = Disables all interrupts
bit 6
PEIE: Peripheral Interrupt Enable bit(2)
1 = Enables all active peripheral interrupts
0 = Disables all peripheral interrupts
bit 5
TMR0IE: Timer0 Overflow Interrupt Enable bit
1 = Enables the Timer0 interrupt
0 = Disables the Timer0 interrupt
bit 4
INTE: INT External Interrupt Enable bit
1 = Enables the INT external interrupt
0 = Disables the INT external interrupt
bit 3
IOCIE: Interrupt-On-Change Enable bit
1 = Enables the Interrupt-On-Change
0 = Disables the Interrupt-On-Change
bit 2
TMR0IF: Timer0 Overflow Interrupt Flag bit
1 = TMR0 register has overflowed
0 = TMR0 register has not overflow
bit 1
INTF: INT External Interrupt Flag bit
1 = The INT external interrupt occurred
0 = The INT external interrupt did not occur
bit 0
IOCIF: Interrupt-On-Change Interrupt Flag bit(3)
1 = When at least one of the Interrupt-On-Change pins changed state
0 = None of the Interrupt-On-Change pins have changed state
Note 1:
2:
3:
Interrupt flag bits are set when an interrupt condition occurs, regardless of the state of its corresponding
enable bit or the Global Interrupt Enable bit, GIE, of the INTCON register. User software should ensure the
appropriate interrupt flag bits are clear prior to enabling an interrupt.
Bit PEIE of the INTCON register must be set to enable any peripheral interrupt.
The IOCIF Flag bit is read-only and cleared when all the Interrupt-On-Change flags in the IOCxF registers
have been cleared by software.
DS40001723D-page 74
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PIC12(L)F1571/2
REGISTER 7-2:
PIE1: PERIPHERAL INTERRUPT ENABLE REGISTER 1
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
U-0
U-0
R/W-0/0
R/W-0/0
TMR1GIE
ADIE
RCIE(1)
TXIE(1)
—
—
TMR2IE
TMR1IE
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
TMR1GIE: Timer1 Gate Interrupt Enable bit
1 = Enables the Timer1 gate acquisition interrupt
0 = Disables the Timer1 gate acquisition interrupt
bit 6
ADIE: Analog-to-Digital Converter (ADC) Interrupt Enable bit
1 = Enables the ADC interrupt
0 = Disables the ADC interrupt
bit 5
RCIE: USART Receive Interrupt Enable bit(1)
1 = Enables the USART receive interrupt
0 = Disables the USART receive interrupt
bit 4
TXIE: USART Transmit Interrupt Enable bit(1)
1 = Enables the USART transmit interrupt
0 = Disables the USART transmit interrupt
bit 3-2
Unimplemented: Read as ‘0’
bit 1
TMR2IE: TMR2 to PR2 Match Interrupt Enable bit
1 = Enables the Timer2 to PR2 match interrupt
0 = Disables the Timer2 to PR2 match interrupt
bit 0
TMR1IE: Timer1 Overflow Interrupt Enable bit
1 = Enables the Timer1 overflow interrupt
0 = Disables the Timer1 overflow interrupt
Note 1:
2:
Note:
PIC12(L)F1572 only.
Bit PEIE of the INTCON register must be set to enable any peripheral interrupt.
Bit PEIE of the INTCON register must be
set to enable any peripheral interrupt.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 75
PIC12(L)F1571/2
REGISTER 7-3:
PIE2: PERIPHERAL INTERRUPT ENABLE REGISTER 2
U-0
U-0
R/W-0/0
U-0
U-0
U-0
U-0
U-0
—
—
C1IE
—
—
—
—
—
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-6
Unimplemented: Read as ‘0’
bit 5
C1IE: Comparator C1 Interrupt Enable bit
1 = Enables the Comparator C1 interrupt
0 = Disables the Comparator C1 interrupt
bit 4-0
Unimplemented: Read as ‘0’
Note:
Bit PEIE of the INTCON register must be
set to enable any peripheral interrupt.
DS40001723D-page 76
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
REGISTER 7-4:
PIE3: PERIPHERAL INTERRUPT ENABLE REGISTER 3
U-0
R/W-0/0
R/W-0/0
R/W-0/0
U-0
U-0
U-0
U-0
—
PWM3IE
PWM2IE
PWM1IE
—
—
—
—
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
Unimplemented: Read as ‘0’
bit 6
PWM3IE: PWM3 Interrupt Enable bit
1 = Enables the PWM3 interrupt
0 = Disables the PWM3 interrupt
bit 5
PWM2IE: PWM2 Interrupt Enable bit
1 = Enables the PWM2 interrupt
0 = Disables the PWM2 interrupt
bit 4
PWM1IE: PWM1 Interrupt Enable bit
1 = Enables the PWM1 interrupt
0 = Disables the PWM1 interrupt
bit 3-0
Unimplemented: Read as ‘0’
Note:
Bit PEIE of the INTCON register must be
set to enable any peripheral interrupt.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 77
PIC12(L)F1571/2
REGISTER 7-5:
R/W-0/0
PIR1: PERIPHERAL INTERRUPT REQUEST REGISTER 1
R/W-0/0
TMR1GIF
R-0/0
ADIF
RCIF
(1)
R/W-0/0
TXIF
(1)
U-0
U-0
R/W-0/0
R/W-0/0
—
—
TMR2IF
TMR1IF
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
TMR1GIF: Timer1 Gate Interrupt Flag bit
1 = Interrupt is pending
0 = Interrupt is not pending
bit 6
ADIF: ADC Interrupt Flag bit
1 = Interrupt is pending
0 = Interrupt is not pending
bit 5
RCIF: USART Receive Interrupt Flag bit(1)
1 = Interrupt is pending
0 = Interrupt is not pending
bit 4
TXIF: USART Transmit Interrupt Flag bit(1)
1 = Interrupt is pending
0 = Interrupt is not pending
bit 3-2
Unimplemented: Read as ‘0’
bit 1
TMR2IF: Timer2 to PR2 Interrupt Flag bit
1 = Interrupt is pending
0 = Interrupt is not pending
bit 0
TMR1IF: Timer1 Overflow Interrupt Flag bit
1 = Interrupt is pending
0 = Interrupt is not pending
Note 1:
Note:
PIC12(L)F1572 only.
Interrupt flag bits are set when an interrupt
condition occurs, regardless of the state of
its corresponding enable bit or the Global
Interrupt Enable bit, GIE, of the INTCON
register. User software should ensure the
appropriate interrupt flag bits are clear prior
to enabling an interrupt.
DS40001723D-page 78
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
REGISTER 7-6:
PIR2: PERIPHERAL INTERRUPT REQUEST REGISTER 2
U-0
U-0
R/W-0/0
U-0
U-0
U-0
U-0
U-0
—
—
C1IF
—
—
—
—
—
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-6
Unimplemented: Read as ‘0’
bit 5
C1IF: Numerically Controlled Oscillator Flag bit
1 = Interrupt is pending
0 = Interrupt is not pending
bit 4-0
Unimplemented: Read as ‘0’
Note:
Interrupt flag bits are set when an interrupt
condition occurs, regardless of the state of
its corresponding enable bit or the Global
Interrupt Enable bit, GIE, of the INTCON
register. User software should ensure the
appropriate interrupt flag bits are clear prior
to enabling an interrupt.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 79
PIC12(L)F1571/2
REGISTER 7-7:
PIR3: PERIPHERAL INTERRUPT REQUEST REGISTER 3
U-0
R-0/0
R-0/0
R-0/0
U-0
U-0
U-0
U-0
—
PWM3IF(1)
PWM2IF(1)
PWM1IF(1)
—
—
—
—
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
Unimplemented: Read as ‘0’
bit 6
PWM3IF: PWM3 Interrupt Flag bit(1)
1 = Interrupt is pending
0 = Interrupt is not pending
bit 5
PWM2IF: PWM2 Interrupt Flag bit(1)
1 = Interrupt is pending
0 = Interrupt is not pending
bit 4
PWM1IF: PWM1 Interrupt Flag bit(1)
1 = Interrupt is pending
0 = Interrupt is not pending
bit 3-0
Unimplemented: Read as ‘0’
Note 1:
2:
These bits are read-only. They must be cleared by addressing the Flag registers inside the module.
Interrupt flag bits are set when an interrupt condition occurs, regardless of the state of its corresponding
enable bit or the Global Enable bit, GIE, of the INTCON register. User software should ensure the
appropriate interrupt flag bits are clear prior to enabling an interrupt.
DS40001723D-page 80
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
TABLE 7-1:
Name
INTCON
SUMMARY OF REGISTERS ASSOCIATED WITH INTERRUPTS
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Register
on Page
GIE
PEIE
TMR0IE
INTE
IOCIE
TMR0IF
INTF
IOCIF
74
OPTION_REG WPUEN
INTEDG TMR0CS TMR0SE
PSA
ADIE
RCIE(1)
TXIE(1)
—
—
TMR2IE
TMR1IE
75
—
C1IE
—
—
—
—
—
76
—
—
—
—
77
—
—
TMR2IF
TMR1IF
78
—
—
—
—
79
—
—
—
—
80
PIE1
TMR1GIE
PIE2
—
PIE3
—
PWM3IE PWM2IE PWM1IE
PIR1
TMR1GIF
ADIF
RCIF(1)
PIR2
—
—
C1IF
—
PIR3
—
PWM3IF
PWM2IF
PWM1IF
TXIF
(1)
PS<2:0>
157
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used by interrupts.
Note 1: PIC12(L)F1572 only.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 81
PIC12(L)F1571/2
NOTES:
DS40001723D-page 82
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
8.0
POWER-DOWN MODE (SLEEP)
The Power-Down mode is entered by executing a
SLEEP instruction.
Upon entering Sleep mode, the following conditions exist:
1.
WDT will be cleared but keeps running if
enabled for operation during Sleep.
PD bit of the STATUS register is cleared.
TO bit of the STATUS register is set.
CPU clock is disabled.
31 kHz LFINTOSC is unaffected and peripherals
that operate from it may continue operation in
Sleep.
Timer1 and peripherals that operate from
Timer1 continue operation in Sleep when the
Timer1 clock source selected is:
• LFINTOSC
• T1CKI
• Timer1 oscillator
ADC is unaffected if the dedicated FRC oscillator
is selected.
I/O ports maintain the status they had before
SLEEP was executed (driving high, low or
high-impedance).
Resets other than WDT are not affected by
Sleep mode.
2.
3.
4.
5.
6.
7.
8.
9.
Refer to individual chapters for more details on
peripheral operation during Sleep.
To minimize current consumption, the following
conditions should be considered:
•
•
•
•
•
•
I/O pins should not be floating
External circuitry sinking current from I/O pins
Internal circuitry sourcing current from I/O pins
Current draw from pins with internal weak pull-ups
Modules using 31 kHz LFINTOSC
CWG module using HFINTOSC
I/O pins that are high-impedance inputs should be
pulled to VDD or VSS externally to avoid switching
currents caused by floating inputs.
Examples of internal circuitry that might be
sourcing current include the FVR module. See
Section 13.0 “Fixed Voltage Reference (FVR)”
for more information on this module.
8.1
Wake-up from Sleep
The first three events will cause a device Reset. The last
three events are considered a continuation of program
execution. To determine whether a device Reset or wakeup event occurred, refer to Section 6.12 “Determining
the Cause of a Reset”.
When the SLEEP instruction is being executed, the next
instruction (PC + 1) is prefetched. For the device to
wake-up through an interrupt event, the corresponding
interrupt enable bit must be enabled. Wake-up will
occur regardless of the state of the GIE bit. If the GIE
bit is disabled, the device continues execution at the
instruction after the SLEEP instruction. If the GIE bit is
enabled, the device executes the instruction after the
SLEEP instruction, the device will then call the Interrupt
Service Routine. In cases where the execution of the
instruction following SLEEP is not desirable, the user
should have a NOP after the SLEEP instruction.
The WDT is cleared when the device wakes up from
Sleep, regardless of the source of wake-up.
8.1.1
WAKE-UP USING INTERRUPTS
When global interrupts are disabled (GIE cleared) and
any interrupt source has both its interrupt enable bit
and interrupt flag bit set, one of the following will occur:
• If the interrupt occurs before the execution of a
SLEEP instruction:
- SLEEP instruction will execute as a NOP.
- WDT and WDT prescaler will not be cleared
- TO bit of the STATUS register will not be set
- PD bit of the STATUS register will not be
cleared.
• If the interrupt occurs during or after the
execution of a SLEEP instruction:
- SLEEP instruction will be completely
executed
- Device will immediately wake-up from Sleep
- WDT and WDT prescaler will be cleared
- TO bit of the STATUS register will be set
- PD bit of the STATUS register will be cleared
Even if the flag bits were checked before executing a
SLEEP instruction, it may be possible for flag bits to
become set before the SLEEP instruction completes. To
determine whether a SLEEP instruction executed, test
the PD bit. If the PD bit is set, the SLEEP instruction
was executed as a NOP.
The device can wake-up from Sleep through one of the
following events:
1. External Reset input on MCLR pin if enabled.
2. BOR Reset if enabled.
3. POR Reset.
4. Watchdog Timer if enabled.
5. Any external interrupt.
6. Interrupts by peripherals capable of running
during Sleep (see individual peripheral for more
information)
 2013-2015 Microchip Technology Inc.
DS40001723D-page 83
PIC12(L)F1571/2
FIGURE 8-1:
WAKE-UP FROM SLEEP THROUGH INTERRUPT
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
CLKIN(1)
TOST(3)
CLKOUT(2)
Interrupt Flag
Interrupt Latency (4)
GIE bit
(INTCON reg.)
Instruction Flow
PC
Instruction
Fetched
Instruction
Executed
Note 1:
2:
3:
4:
8.2
Processor in
Sleep
PC
PC + 1
PC + 2
PC + 2
Inst(PC) = Sleep
Inst(PC + 1)
Inst(PC + 2)
Inst(PC – 1)
Sleep
Inst(PC + 1)
PC + 2
Forced NOP
0004h
0005h
Inst(0004h)
Inst(0005h)
Forced NOP
Inst(0004h)
External Clock. High, Medium, Low mode assumed.
CLKOUT is shown here for timing reference.
TOST = 1024 TOSC. This delay does not apply to EC, RC and INTOSC Oscillator modes or Two-Speed Start-up (if available).
GIE = 1 assumed. In this case, after wake-up, the processor calls the ISR at 0004h. If GIE = 0, execution will continue in-line.
Low-Power Sleep Mode
8.2.2
PERIPHERAL USAGE IN SLEEP
This device contains an internal Low Dropout (LDO)
voltage regulator, which allows the device I/O pins to
operate at voltages up to 5.5V while the internal device
logic operates at a lower voltage. The LDO and its
associated reference circuitry must remain active when
the device is in Sleep mode.
Some peripherals that can operate in Sleep mode will
not operate properly with the Low-Power Sleep mode
selected. The LDO will remain in the normal power
mode when those peripherals are enabled. The LowPower Sleep mode is intended for use with these
peripherals:
Low-Power Sleep mode allows the user to optimize the
operating current in Sleep. Low-Power Sleep mode can
be selected by setting the VREGPM bit of the
VREGCON register, which puts the LDO and reference
circuitry in a low-power state whenever the device is in
Sleep.
•
•
•
•
8.2.1
SLEEP CURRENT VS. WAKE-UP
TIME
In the default operating mode, the LDO and reference
circuitry remain in the normal configuration while in
Sleep. The device is able to exit Sleep mode quickly
since all circuits remain active. In Low-Power Sleep
mode, when waking up from Sleep, an extra delay time
is required for these circuits to return to the normal
configuration and stabilize.
The Low-Power Sleep mode is beneficial for applications that stay in Sleep mode for long periods of time.
The normal mode is beneficial for applications that
need to wake from Sleep quickly and frequently.
DS40001723D-page 84
Brown-out Reset (BOR)
Watchdog Timer (WDT)
External interrupt pin/Interrupt-On-Change pins
Timer1 (with external clock source)
The Complementary Waveform Generator (CWG)
module can utilize the HFINTOSC oscillator as either
a clock source or as an input source. Under certain
conditions, when the HFINTOSC is selected for use
with the CWG module, the HFINTOSC will remain
active during Sleep. This will have a direct effect on
the Sleep mode current.
Please refer to section Section 23.10 “Operation
During Sleep” for more information.
Note:
The PIC12LF1571/2 does not have a
configurable Low-Power Sleep mode.
PIC12LF1571/2 is an unregulated device
and is always in the lowest power state
when in Sleep with no wake-up time penalty.
This device has a lower maximum VDD and
I/O voltage than the PIC12F1571/2. See
Section 26.0 “Electrical Specifications”
for more information.
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
8.3
Register Definitions: Voltage Regulator Control
VREGCON: VOLTAGE REGULATOR CONTROL REGISTER(1)
REGISTER 8-1:
U-0
U-0
U-0
U-0
U-0
U-0
R/W-0/0
R/W-1/1
—
—
—
—
—
—
VREGPM
Reserved
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-2
Unimplemented: Read as ‘0’
bit 1
VREGPM: Voltage Regulator Power Mode Selection bit
1 = Low-Power Sleep mode enabled in Sleep(2)
Draws lowest current in Sleep, slower wake-up.
0 = Normal power mode enabled in Sleep(2)
Draws higher current in Sleep, faster wake-up.
bit 0
Reserved: Read as ‘1’, maintain this bit set
Note 1:
2:
PIC12F1571/2 only.
See Section 26.0 “Electrical Specifications”
TABLE 8-1:
SUMMARY OF REGISTERS ASSOCIATED WITH POWER-DOWN MODE
Name
Bit 7
Bit 6
Bit 5
INTCON
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Register on
Page
GIE
PEIE
TMR0IE
INTE
IOCIE
TMR0IF
INTF
IOCIF
74
IOCAF
—
—
IOCAF5
IOCAF4
IOCAF3
IOCAF2
IOCAF1
IOCAF0
122
IOCAN
—
—
IOCAN5
IOCAN4
IOCAN3
IOCAN2
IOCAN1
IOCAN0
121
IOCAP
—
—
IOCAP5
IOCAP4
IOCAP3
IOCAP2
IOCAP1
IOCAP0
121
TXIE(1)
PIE1
TMR1GIE
ADIE
RCIE(1)
—
—
TMR2IE
TMR1IE
75
PIE2
—
—
C1IE
—
—
—
—
—
76
PIE3
—
PWM3IE
PWM2IE
PWM1IE
—
—
—
—
77
PIR1
TMR1GIF
ADIF
RCIF(1)
TXIF(1)
—
—
TMR2IF
TMR1IF
78
PIR2
—
—
C1IF
—
—
—
—
—
79
PIR3
—
PWM3IF
PWM2IF
PWM1IF
—
—
—
—
80
STATUS
—
—
—
TO
PD
Z
DC
C
19
WDTCON
—
—
SWDTEN
89
WDTPS<4:0>
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used in Power-Down mode.
Note 1: PIC12(L)F1572 only.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 85
PIC12(L)F1571/2
NOTES:
DS40001723D-page 86
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
9.0
WATCHDOG TIMER (WDT)
The Watchdog Timer is a system timer that generates
a Reset if the firmware does not issue a CLRWDT
instruction within the time-out period. The Watchdog
Timer is typically used to recover the system from
unexpected events.
FIGURE 9-1:
The WDT has the following features:
• Independent clock source
• Multiple operating modes:
- WDT is always on
- WDT is off when in Sleep
- WDT is controlled by software
- WDT is always off
• Configurable time-out period is from 1 ms to
256 seconds (nominal)
• Multiple Reset conditions
• Operation during Sleep
WATCHDOG TIMER BLOCK DIAGRAM
Rev. 10-000141A
7/30/2013
WDTE<1:0> = 01
SWDTEN
WDTE<1:0> = 11
LFINTOSC
23-%it Programmable
Prescaler WDT
WDT
Time-out
WDTE<1:0> = 10
Sleep
 2013-2015 Microchip Technology Inc.
WDTPS<4:0>
DS40001723D-page 87
PIC12(L)F1571/2
9.1
Independent Clock Source
9.3
The WDT derives its time base from the 31 kHz
LFINTOSC internal oscillator. Time intervals in this
chapter are based on a nominal interval of 1 ms. See
Section 26.0 “Electrical Specifications” for the
LFINTOSC tolerances.
9.2
The Watchdog Timer module has four operating modes
controlled by the WDTE<1:0> bits in the Configuration
Words. See Table 9-1.
9.2.1
WDT IS ALWAYS ON
When the WDTEx bits of the Configuration Words are
set to ‘11’, the WDT is always on. WDT protection is
active during Sleep.
9.2.2
WDT IS OFF IN SLEEP
When the WDTEx bits of the Configuration Words are
set to ‘10’, the WDT is on, except in Sleep. WDT
protection is not active during Sleep.
9.2.3
WDT CONTROLLED BY SOFTWARE
When the WDTEx bits of the Configuration Words are
set to ‘01’, the WDT is controlled by the SWDTEN bit of
the WDTCON register.
WDT protection is unchanged by Sleep. See Table 9-1
for more details.
TABLE 9-1:
WDT OPERATING MODES
WDTE<1:0>
SWDTEN
11
X
10
X
01
00
TABLE 9-2:
Device
Mode
The WDTPS<4:0> bits of the WDTCON register set the
time-out period from 1 ms to 256 seconds (nominal).
After a Reset, the default time-out period is two
seconds.
9.4
WDT Operating Modes
WDT
Mode
X
Active
Awake
Active
Sleep
Disabled
1
X
Active
0
X
Disabled
X
X
Disabled
Time-out Period
Clearing the WDT
The WDT is cleared when any of the following conditions
occur:
•
•
•
•
•
•
•
Any Reset
CLRWDT instruction is executed
Device enters Sleep
Device wakes up from Sleep
Oscillator fails
WDT is disabled
Oscillator Start-up Timer (OST) is running
See Table 9-2 for more information.
9.5
Operation During Sleep
When the device enters Sleep, the WDT is cleared. If
the WDT is enabled during Sleep, the WDT resumes
counting. When the device exits Sleep, the WDT is
cleared again.
The WDT remains clear until the OST, if enabled, completes. See Section 5.0 “Oscillator Module” for more
information on the OST.
When a WDT time-out occurs while the device is in
Sleep, no Reset is generated. Instead, the device
wakes up and resumes operation. The TO and PD bits
in the STATUS register are changed to indicate the
event. The RWDT bit in the PCON register can also be
used. See Section 3.0 “Memory Organization” for
more information.
WDT CLEARING CONDITIONS
Conditions
WDT
WDTE<1:0> = 00
WDTE<1:0> = 01 and SWDTEN = 0
WDTE<1:0> = 10 and enter Sleep
CLRWDT Command
Cleared
Oscillator Fail Detected
Exit Sleep + System Clock = T1OSC, EXTRC, INTOSC, EXTCLK
Exit Sleep + System Clock = XT, HS, LP
Change INTOSC divider (IRCF<3:0> bits)
DS40001723D-page 88
Cleared until the end of OST
Unaffected
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
9.6
Register Definitions: Watchdog Control
REGISTER 9-1:
WDTCON: WATCHDOG TIMER CONTROL REGISTER
U-0
U-0
—
—
R/W-0/0
R/W-1/1
R/W-0/0
R/W-1/1
R/W-1/1
WDTPS<4:0>
bit 7
R/W-0/0
SWDTEN
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-6
Unimplemented: Read as ‘0’
bit 5-1
WDTPS<4:0>: Watchdog Timer Period Select bits(1)
Bit Value = Prescale Rate
11111 = Reserved; results in minimum interval (1:32)
•
•
•
10011 = Reserved; results in minimum interval (1:32)
10010 = 1:8388608 (223) (Interval 256s nominal)
10001 = 1:4194304 (222) (Interval 128s nominal)
10000 = 1:2097152 (221) (Interval 64s nominal)
01111 = 1:1048576 (220) (Interval 32s nominal)
01110 = 1:524288 (219) (Interval 16s nominal)
01101 = 1:262144 (218) (Interval 8s nominal)
01100 = 1:131072 (217) (Interval 4s nominal)
01011 = 1:65536 (Interval 2s nominal) (Reset value)
01010 = 1:32768 (Interval 1s nominal)
01001 = 1:16384 (Interval 512 ms nominal)
01000 = 1:8192 (Interval 256 ms nominal)
00111 = 1:4096 (Interval 128 ms nominal)
00110 = 1:2048 (Interval 64 ms nominal)
00101 = 1:1024 (Interval 32 ms nominal)
00100 = 1:512 (Interval 16 ms nominal)
00011 = 1:256 (Interval 8 ms nominal)
00010 = 1:128 (Interval 4 ms nominal)
00001 = 1:64 (Interval 2 ms nominal)
00000 = 1:32 (Interval 1 ms nominal)
bit 0
SWDTEN: Software Enable/Disable for Watchdog Timer bit
If WDTE<1:0> = 1x:
This bit is ignored.
If WDTE<1:0> = 01:
1 = WDT is turned on
0 = WDT is turned off
If WDTE<1:0> = 00:
This bit is ignored.
Note 1:
Times are approximate. WDT time is based on 31 kHz LFINTOSC.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 89
PIC12(L)F1571/2
TABLE 9-3:
SUMMARY OF REGISTERS ASSOCIATED WITH WATCHDOG TIMER
Name
Bit 7
Bit 6
Bit 5
Bit 4
OSCCON
SPLLEN
PCON
STKOVF
STKUNF
—
RWDT
STATUS
—
—
—
TO
WDTCON
—
—
Bit 3
IRCF<3:0>
Bit 2
Bit 1
—
Bit 0
SCS<1:0>
RMCLR
RI
POR
PD
Z
DC
WDTPS<4:0>
Register
on Page
55
BOR
66
C
19
SWDTEN
89
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used by the Watchdog Timer.
TABLE 9-4:
Name
Bits
SUMMARY OF CONFIGURATION WORD WITH WATCHDOG TIMER
Bit -/7
Bit -/6
Bit 13/5
Bit 12/4
Bit 11/3
CONFIG1 13:8
—
—
—
—
CLKOUTEN
7:0
CP
MCLRE
PWRTE
WDTE<1:0>
Bit 10/2
Bit 9/1
BOREN<1:0>
—
Bit 8/0
Register
on Page
—
42
FOSC<1:0>
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used by the Watchdog Timer.
DS40001723D-page 90
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
10.0
FLASH PROGRAM MEMORY
CONTROL
The Flash program memory is readable and writable
during normal operation over the full VDD range.
Program memory is indirectly addressed using Special
Function Registers (SFRs). The SFRs used to access
program memory are:
•
•
•
•
•
•
PMCON1
PMCON2
PMDATL
PMDATH
PMADRL
PMADRH
When accessing the program memory, the
PMDATH:PMDATL register pair forms a 2-byte word
that holds the 14-bit data for read/write, and the
PMADRH:PMADRL register pair forms a 2-byte word
that holds the 15-bit address of the program memory
location being read.
The write time is controlled by an on-chip timer. The
write/erase voltages are generated by an on-chip charge
pump.
The Flash program memory can be protected in two
ways; by code protection (CP bit in the Configuration
Words) and write protection (WRT<1:0> bits in the
Configuration Words).
Code protection (CP = 0) disables access, reading and
writing, to the Flash program memory via external
device programmers. Code protection does not affect
the self-write and erase functionality. Code protection
can only be reset by a device programmer performing
a bulk erase to the device, clearing all Flash program
memory, Configuration bits and User IDs.(1)
Write protection prohibits self-write and erase to a
portion or all of the Flash program memory as defined
by the bits WRT<1:0>. Write protection does not affect
a device programmers ability to read, write or erase the
device.
Note 1: Code protection of the entire Flash
program memory array is enabled by
clearing the CP bit of the Configuration
Words.
10.1
The PMADRH:PMADRL register pair can address up
to a maximum of 16K words of program memory. When
selecting a program address value, the MSB of the
address is written to the PMADRH register and the LSB
is written to the PMADRL register.
10.1.1
PMCON1 AND PMCON2
REGISTERS
PMCON1 is the control register for Flash program
memory accesses.
Control bits, RD and WR, initiate read and write,
respectively. These bits cannot be cleared, only set, in
software. They are cleared by hardware at completion
of the read or write operation. The inability to clear the
WR bit in software prevents the accidental, premature
termination of a write operation.
The WREN bit, when set, will allow a write operation to
occur. On power-up, the WREN bit is clear. The
WRERR bit is set when a write operation is interrupted
by a Reset during normal operation. In these situations,
following Reset, the user can check the WRERR bit
and execute the appropriate error handling routine.
The PMCON2 register is a write-only register. Attempting
to read the PMCON2 register will return all ‘0’s.
To enable writes to the program memory, a specific
pattern (the unlock sequence), must be written to the
PMCON2 register. The required unlock sequence
prevents inadvertent writes to the program memory
write latches and Flash program memory.
10.2
Flash Program Memory Overview
It is important to understand the Flash program memory
structure for erase and programming operations. Flash
program memory is arranged in rows. A row consists of
a fixed number of 14-bit program memory words. A row
is the minimum size that can be erased by user software.
After a row has been erased, the user can reprogram
all or a portion of this row. Data to be written into the
program memory row is written to 14-bit wide data write
latches. These write latches are not directly accessible
to the user, but may be loaded via sequential writes to
the PMDATH:PMDATL register pair.
Note:
 2013-2015 Microchip Technology Inc.
PMADRL and PMADRH Registers
If the user wants to modify only a portion of
a previously programmed row, then the
contents of the entire row must be read and
saved in RAM prior to the erase. Then, new
data and retained data can be written into
the write latches to reprogram the row of
Flash program memory. However, any
unprogrammed locations can be written
without first erasing the row. In this case, it
is not necessary to save and rewrite the
other previously programmed locations.
DS40001723D-page 91
PIC12(L)F1571/2
See Table 10-1 for erase row size and the number of
write latches for Flash program memory.
TABLE 10-1:
FLASH MEMORY
ORGANIZATION BY DEVICE
Device
PIC12(L)F1571
PIC12(L)F1572
10.2.1
Row Erase
(words)
Write
Latches
(words)
16
16
2.
3.
Write the desired address to the
PMADRH:PMADRL register pair.
Clear the CFGS bit of the PMCON1 register.
Then, set control bit, RD, of the PMCON1 register.
Once the read control bit is set, the program memory
Flash controller will use the second instruction cycle to
read the data. This causes the second instruction
immediately following the “BSF PMCON1,RD” instruction
to be ignored. The data is available in the very next cycle
in the PMDATH:PMDATL register pair; therefore, it can
be read as two bytes in the following instructions.
The PMDATH:PMDATL register pair will hold this value
until another read or until it is written to by the user.
Note:
FLASH PROGRAM
MEMORY READ
FLOWCHART
Rev. 10-000046A
7/30/2013
Start
Read Operation
Select
Program or Configuration Memory
(CFGS)
READING THE FLASH PROGRAM
MEMORY
To read a program memory location, the user must:
1.
FIGURE 10-1:
The two instructions following a program
memory read are required to be NOPs.
This prevents the user from executing a
2-cycle instruction on the next instruction
after the RD bit is set.
Select
Word Address
(PMADRH:PMADRL)
Initiate Read operation
(RD = 1)
Instruction fetched ignored
NOP execution forced
Instruction fetched ignored
NOP execution forced
Data read now in
PMDATH:PMDATL
End
Read Operation
DS40001723D-page 92
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
FIGURE 10-2:
FLASH PROGRAM MEMORY READ CYCLE EXECUTION
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
PC
Flash ADDR
Flash Data
PC + 1
INSTR (PC)
INSTR(PC – 1)
Executed Here
PMADRH,PMADRL
INSTR (PC + 1)
BSF PMCON1,RD
Executed Here
PC
+3
PC+3
PMDATH,PMDATL
INSTR(PC + 1)
Instruction Ignored,
Forced NOP
Executed Here
PC + 5
PC + 4
INSTR (PC + 3)
INSTR(PC + 2)
Instruction Ignored,
Forced NOP
Executed Here
INSTR (PC + 4)
INSTR(PC + 3)
Executed Here
INSTR(PC + 4)
Executed Here
RD bit
PMDATH
PMDATL
Register
EXAMPLE 10-1:
FLASH PROGRAM MEMORY READ
* This code block will read 1 word of program
* memory at the memory address:
PROG_ADDR_HI : PROG_ADDR_LO
*
data will be returned in the variables;
*
PROG_DATA_HI, PROG_DATA_LO
BANKSEL
MOVLW
MOVWF
MOVLW
MOVWF
PMADRL
PROG_ADDR_LO
PMADRL
PROG_ADDR_HI
PMADRH
; Select Bank for PMCON registers
;
; Store LSB of address
;
; Store MSB of address
BCF
BSF
NOP
NOP
PMCON1,CFGS
PMCON1,RD
;
;
;
;
Do not select Configuration Space
Initiate read
Ignored (Figure 10-2)
Ignored (Figure 10-2)
MOVF
MOVWF
MOVF
MOVWF
PMDATL,W
PROG_DATA_LO
PMDATH,W
PROG_DATA_HI
;
;
;
;
Get LSB of word
Store in user location
Get MSB of word
Store in user location
 2013-2015 Microchip Technology Inc.
DS40001723D-page 93
PIC12(L)F1571/2
10.2.2
FLASH MEMORY UNLOCK
SEQUENCE
The unlock sequence is a mechanism that protects the
Flash program memory from unintended self-write
programming or erasing. The sequence must be executed and completed without interruption to successfully
complete any of the following operations:
• Row erase
• Load program memory write latches
• Write of program memory write latches to
program memory
• Write of program memory write latches to User
IDs
FIGURE 10-3:
FLASH PROGRAM
MEMORY UNLOCK
SEQUENCE FLOWCHART
Rev. 10-000047A
7/30/2013
Start
Unlock Sequence
Write 0x55 to
PMCON2
The unlock sequence consists of the following steps:
1. Write 55h to PMCON2
2. Write AAh to PMCON2
Write 0xAA to
PMCON2
3. Set the WR bit in PMCON1
4. NOP instruction
5. NOP instruction
Once the WR bit is set, the processor will always force
two NOP instructions. When an erase row or program row
operation is being performed, the processor will stall
internal operations (typical 2 ms), until the operation is
complete and then resume with the next instruction.
When the operation is loading the program memory write
latches, the processor will always force the two NOP
instructions and continue uninterrupted with the next
instruction.
Initiate
Write or Erase operation
(WR = 1)
Instruction fetched ignored
NOP execution forced
Instruction fetched ignored
NOP execution forced
Since the unlock sequence must not be interrupted,
global interrupts should be disabled prior to the unlock
sequence and re-enabled after the unlock sequence is
completed.
End
Unlock Sequence
DS40001723D-page 94
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
10.2.3
ERASING FLASH PROGRAM
MEMORY
While executing code, program memory can only be
erased by rows. To erase a row:
1.
2.
3.
4.
5.
Load the PMADRH:PMADRL register pair with
any address within the row to be erased.
Clear the CFGS bit of the PMCON1 register.
Set the FREE and WREN bits of the PMCON1
register.
Write 55h, then AAh, to PMCON2 (Flash
programming unlock sequence).
Set control bit, WR, of the PMCON1 register to
begin the erase operation.
FIGURE 10-4:
FLASH PROGRAM
MEMORY ERASE
FLOWCHART
Rev. 10-000048A
7/30/2013
Start
Erase Operation
Disable Interrupts
(GIE = 0)
See Example 10-2.
After the “BSF PMCON1,WR” instruction, the processor
requires two cycles to set up the erase operation. The
user must place two NOP instructions after the WR bit is
set. The processor will halt internal operations for the
typical 2 ms erase time. This is not Sleep mode as the
clocks and peripherals will continue to run. After the
erase cycle, the processor will resume operation with
the third instruction after the PMCON1 write instruction.
Select
Program or Configuration Memory
(CFGS)
Select Row Address
(PMADRH:PMADRL)
Select Erase Operation
(FREE = 1)
Enable Write/Erase Operation
(WREN = 1)
Unlock Sequence
(See Note 1)
CPU stalls while
Erase operation completes
(2 ms typical)
Disable Write/Erase Operation
(WREN = 0)
Re-enable Interrupts
(GIE = 1)
End
Erase Operation
Note 1: See Figure 10-3.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 95
PIC12(L)F1571/2
EXAMPLE 10-2:
ERASING ONE ROW OF PROGRAM MEMORY
Required
Sequence
; This row erase routine assumes the following:
; 1. A valid address within the erase row is loaded in ADDRH:ADDRL
; 2. ADDRH and ADDRL are located in shared data memory 0x70 - 0x7F (common RAM)
BCF
BANKSEL
MOVF
MOVWF
MOVF
MOVWF
BCF
BSF
BSF
INTCON,GIE
PMADRL
ADDRL,W
PMADRL
ADDRH,W
PMADRH
PMCON1,CFGS
PMCON1,FREE
PMCON1,WREN
MOVLW
MOVWF
MOVLW
MOVWF
BSF
NOP
NOP
55h
PMCON2
0AAh
PMCON2
PMCON1,WR
BCF
BSF
DS40001723D-page 96
PMCON1,WREN
INTCON,GIE
; Disable ints so required sequences will execute properly
; Load lower 8 bits of erase address boundary
; Load upper 6 bits of erase address boundary
; Not configuration space
; Specify an erase operation
; Enable writes
;
;
;
;
;
;
;
;
;
;
Start of required sequence to initiate erase
Write 55h
Write AAh
Set WR bit to begin erase
NOP instructions are forced as processor starts
row erase of program memory.
The processor stalls until the erase process is complete
after erase processor continues with 3rd instruction
; Disable writes
; Enable interrupts
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
10.2.4
WRITING TO FLASH PROGRAM
MEMORY
Program memory is programmed using the following
steps:
1.
2.
3.
4.
Load the address in PMADRH:PMADRL of the
row to be programmed.
Load each write latch with data.
Initiate a programming operation.
Repeat Steps 1 through 3 until all data is written.
Before writing to program memory, the word(s) to be
written must be erased or previously unwritten. Program memory can only be erased one row at a time. No
automatic erase occurs upon the initiation of the write.
Program memory can be written one or more words at
a time. The maximum number of words written at one
time is equal to the number of write latches. See
Figure 10-5 (row writes to program memory with
16 write latches) for more details.
The write latches are aligned to the Flash row
address boundary defined by the upper 11 bits of
PMADRH:PMADRL (PMADRH<6:0>:PMADRL<7:4>),
with the lower 4 bits of PMADRL (PMADRL<3:0>)
determining the write latch being loaded. Write operations do not cross these boundaries. At the completion
of a program memory write operation, the data in the
write latches is reset to contain 0x3FFF.
The following steps should be completed to load the
write latches and program a row of program memory.
These steps are divided into two parts. First, each write
latch is loaded with data from the PMDATH:PMDATL
using the unlock sequence with LWLO = 1. When the
last word to be loaded into the write latch is ready, the
LWLO bit is cleared and the unlock sequence
executed. This initiates the programming operation,
writing all the latches into Flash program memory.
Note:
The special unlock sequence is required
to load a write latch with data or initiate a
Flash programming operation. If the
unlock sequence is interrupted, writing to
the latches or program memory will not be
initiated.
 2013-2015 Microchip Technology Inc.
1.
2.
3.
Set the WREN bit of the PMCON1 register.
Clear the CFGS bit of the PMCON1 register.
Set the LWLO bit of the PMCON1 register.
When the LWLO bit of the PMCON1 register is
‘1’, the write sequence will only load the write
latches and will not initiate the write to Flash
program memory.
4. Load the PMADRH:PMADRL register pair with
the address of the location to be written.
5. Load the PMDATH:PMDATL register pair with
the program memory data to be written.
6. Execute
the
unlock
sequence
(Section 10.2.2 “Flash Memory Unlock
Sequence”). The write latch is now loaded.
7. Increment the PMADRH:PMADRL register pair
to point to the next location.
8. Repeat Steps 5 through 7 until all but the last
write latch has been loaded.
9. Clear the LWLO bit of the PMCON1 register.
When the LWLO bit of the PMCON1 register is
‘0’, the write sequence will initiate the write to
Flash program memory.
10. Load the PMDATH:PMDATL register pair with
the program memory data to be written.
11. Execute
the
unlock
sequence
(Section 10.2.2 “Flash Memory Unlock
Sequence”). The entire program memory latch
content is now written to Flash program
memory.
Note:
The program memory write latches are
reset to the blank state (0x3FFF) at the
completion of every write or erase
operation. As a result, it is not necessary
to load all the program memory write
latches. Unloaded latches will remain in
the blank state.
An example of the complete write sequence is shown in
Example 10-3. The initial address is loaded into the
PMADRH:PMADRL register pair; the data is loaded
using Indirect Addressing.
DS40001723D-page 97
7
BLOCK WRITES TO FLASH PROGRAM MEMORY WITH 16 WRITE LATCHES
6
0 7
4
PMADRH
-
rA
r9
r8
r7
r6
3
0
7
PMADRL
r5
r4
r3
r2
r1
r0
c3
c2
c1
-
5
-
0
7
PMDATH
PMDATL
6
c0
Rev. 10-000004B
7/25/2013
0
8
14
11
Program Memory Write Latches
4
14
Write Latch #0
00h
14
14
14
Write Latch #14
0Eh
Write Latch #1
01h
Write Latch #15
0Fh
PMADRL<3:0>
14
CFGS = 0
 2013-2015 Microchip Technology Inc.
PMADRH<6:0>:
PMADRL<7:4>
Row
Address
Decode
14
14
14
Row
Addr
Addr
Addr
Addr
000h
0000h
0001h
000Eh
000Fh
001h
0010h
0011h
001Eh
001Fh
002h
0020h
0021h
002Eh
002Fh
7FEh
7FE0h
7FE1h
7FEEh
7FEFh
7FFh
7FF0h
7FF1h
7FFEh
7FFFh
Flash Program Memory
800h
CFGS = 1
8000h - 8003h
8004h – 8005h
8006h
8007h – 8008h
8009h - 801Fh
USER ID 0 - 3
reserved
DEVICE ID
Dev / Rev
Configuration
Words
reserved
Configuration Memory
PIC12(L)F1571/2
DS40001723D-page 98
FIGURE 10-5:
PIC12(L)F1571/2
FIGURE 10-6:
FLASH PROGRAM MEMORY WRITE FLOWCHART
Start
Write Operation
Determine number of words
to be written into Program or
Configuration Memory.
The number of words cannot
exceed the number of words
per row.
(word_cnt)
Disable Interrupts
(GIE = 0)
Select
Program or Config. Memory
(CFGS)
Select Row Address
(PMADRH:PMADRL)
Enable Write/Erase
Operation (WREN = 1)
Load the value to write
(PMDATH:PMDATL)
Update the word counter
(word_cnt--)
Last word to
write ?
Yes
No
Unlock Sequence
(Figure10-3
x-x)
Figure
Select Write Operation
(FREE = 0)
No delay when writing to
Program Memory Latches
Load Write Latches Only
(LWLO = 1)
Increment Address
(PMADRH:PMADRL++)
Write Latches to Flash
(LWLO = 0)
Unlock Sequence
(Figure10-3
x-x)
Figure
CPU stalls while Write
operation completes
(2ms typical)
Disable
Write/Erase Operation
(WREN = 0)
Re-enable Interrupts
(GIE = 1)
End
Write Operation
 2013-2015 Microchip Technology Inc.
DS40001723D-page 99
PIC12(L)F1571/2
EXAMPLE 10-3:
;
;
;
;
;
;
;
WRITING TO FLASH PROGRAM MEMORY
This write routine assumes the following:
1. 32 bytes of data are loaded, starting at the address in DATA_ADDR
2. Each word of data to be written is made up of two adjacent bytes in DATA_ADDR,
stored in little endian format
3. A valid starting address (the Least Significant bits = 00000) is loaded in ADDRH:ADDRL
4. ADDRH and ADDRL are located in shared data memory 0x70 - 0x7F (common RAM)
BCF
BANKSEL
MOVF
MOVWF
MOVF
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
BCF
BSF
BSF
INTCON,GIE
PMADRH
ADDRH,W
PMADRH
ADDRL,W
PMADRL
LOW DATA_ADDR
FSR0L
HIGH DATA_ADDR
FSR0H
PMCON1,CFGS
PMCON1,WREN
PMCON1,LWLO
;
;
;
;
;
;
;
;
;
;
;
;
;
Disable ints so required sequences will execute properly
Bank 3
Load initial address
MOVIW
MOVWF
MOVIW
MOVWF
FSR0++
PMDATL
FSR0++
PMDATH
; Load first data byte into lower
;
; Load second data byte into upper
;
MOVF
XORLW
ANDLW
BTFSC
GOTO
PMADRL,W
0x1F
0x1F
STATUS,Z
START_WRITE
; Check if lower bits of address are '00000'
; Check if we're on the last of 16 addresses
;
; Exit if last of 16 words,
;
MOVLW
MOVWF
MOVLW
MOVWF
BSF
NOP
55h
PMCON2
0AAh
PMCON2
PMCON1,WR
;
;
;
;
;
;
;
;
PMADRL,F
LOOP
; Still loading latches Increment address
; Write next latches
PMCON1,LWLO
; No more loading latches - Actually start Flash program
; memory write
55h
PMCON2
0AAh
PMCON2
PMCON1,WR
;
;
;
;
;
;
;
;
;
;
;
;
;
Load initial data address
Load initial data address
Not configuration space
Enable writes
Only Load Write Latches
Required
Sequence
LOOP
NOP
INCF
GOTO
Required
Sequence
START_WRITE
BCF
MOVLW
MOVWF
MOVLW
MOVWF
BSF
NOP
NOP
BCF
BSF
DS40001723D-page 100
PMCON1,WREN
INTCON,GIE
Start of required write sequence:
Write 55h
Write AAh
Set WR bit to begin write
NOP instructions are forced as processor
loads program memory write latches
Start of required write sequence:
Write 55h
Write AAh
Set WR bit to begin write
NOP instructions are forced as processor writes
all the program memory write latches simultaneously
to program memory.
After NOPs, the processor
stalls until the self-write process in complete
after write processor continues with 3rd instruction
Disable writes
Enable interrupts
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
10.3
Modifying Flash Program Memory
When modifying existing data in a program memory
row, and data within that row must be preserved, it must
first be read and saved in a RAM image. Program
memory is modified using the following steps:
1.
2.
3.
4.
5.
6.
7.
Load the starting address of the row to be
modified.
Read the existing data from the row into a RAM
image.
Modify the RAM image to contain the new data
to be written into program memory.
Load the starting address of the row to be
rewritten.
Erase the program memory row.
Load the write latches with data from the RAM
image.
Initiate a programming operation.
FIGURE 10-7:
FLASH PROGRAM
MEMORY MODIFY
FLOWCHART
Rev. 10-000050A
7/30/2013
Start
Modify Operation
Read Operation
(See Note 1)
An image of the entire row
read must be stored in RAM
Modify Image
The words to be modified are
changed in the RAM image
Erase Operation
(See Note 2)
Write Operation
Use RAM image
(See Note 3)
End
Modify Operation
Note 1: See Figure 10-2.
2: See Figure 10-4.
3: See Figure 10-6.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 101
PIC12(L)F1571/2
10.4
User ID, Device ID and
Configuration Word Access
When read access is initiated on an address outside the
parameters listed in Table 10-2, the PMDATH:PMDATL
register pair is cleared, reading back ‘0’s.
Instead of accessing program memory, the User IDs,
Device ID/Revision ID and Configuration Words can be
accessed when CFGS = 1 in the PMCON1 register.
This is the region that would be pointed to by
PC<15> = 1, but not all addresses are accessible.
Different access may exist for reads and writes. Refer
to Table 10-2.
TABLE 10-2:
USER ID, DEVICE ID AND CONFIGURATION WORD ACCESS (CFGS = 1)
Address
Function
Read Access
Write Access
8000h-8003h
User IDs
Yes
Yes
8006h/8005h
Device ID/Revision ID
Yes
No
8007h-8008h
Configuration Words 1 and 2
Yes
No
EXAMPLE 10-4:
CONFIGURATION WORD AND DEVICE ID ACCESS
* This code block will read 1 word of program memory at the memory address:
*
PROG_ADDR_LO (must be 00h-08h) data will be returned in the variables;
*
PROG_DATA_HI, PROG_DATA_LO
BANKSEL
MOVLW
MOVWF
CLRF
PMADRL
PROG_ADDR_LO
PMADRL
PMADRH
; Select correct Bank
;
; Store LSB of address
; Clear MSB of address
BSF
BCF
BSF
NOP
NOP
BSF
PMCON1,CFGS
INTCON,GIE
PMCON1,RD
INTCON,GIE
;
;
;
;
;
;
Select Configuration Space
Disable interrupts
Initiate read
Executed (See Figure 10-2)
Ignored (See Figure 10-2)
Restore interrupts
MOVF
MOVWF
MOVF
MOVWF
PMDATL,W
PROG_DATA_LO
PMDATH,W
PROG_DATA_HI
;
;
;
;
Get LSB of word
Store in user location
Get MSB of word
Store in user location
DS40001723D-page 102
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
10.5
Write Verify
It is considered good programming practice to verify that
program memory writes agree with the intended value.
Since program memory is stored as a full page then the
stored program memory contents are compared with the
intended data stored in RAM after the last write is
complete.
FIGURE 10-8:
FLASH PROGRAM
MEMORY VERIFY
FLOWCHART
Rev. 10-000051A
7/30/2013
Start
Verify Operation
This routine assumes that the last
row of data written was from an
image saved on RAM. This image
will be used to verify the data
currently stored in Flash Program
Memory
Read Operation
(See Note 1)
PMDAT =
RAM image ?
No
Yes
Fail
Verify Operation
No
Last word ?
Yes
End
Verify Operation
Note 1: See Figure 10-1.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 103
PIC12(L)F1571/2
10.6
Register Definitions: Flash Program Memory Control
REGISTER 10-1:
R/W-x/u
PMDATL: PROGRAM MEMORY DATA LOW BYTE REGISTER
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
PMDAT<7:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-0
PMDAT<7:0>: Read/Write Value for Least Significant bits of Program Memory bits
REGISTER 10-2:
PMDATH: PROGRAM MEMORY DATA HIGH BYTE REGISTER
U-0
U-0
—
—
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
PMDAT<13:8>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-6
Unimplemented: Read as ‘0’
bit 5-0
PMDAT<13:8>: Read/Write Value for Most Significant bits of Program Memory bits
DS40001723D-page 104
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
REGISTER 10-3:
R/W-0/0
PMADRL: PROGRAM MEMORY ADDRESS LOW BYTE REGISTER
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
PMADR<7:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-0
PMADR<7:0>: Specifies Least Significant bits for Program Memory Address bits
REGISTER 10-4:
U-1
PMADRH: PROGRAM MEMORY ADDRESS HIGH BYTE REGISTER
R/W-0/0
R/W-0/0
R/W-0/0
—(1)
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
PMADR<14:8>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
Unimplemented: Read as ‘1’(1)
bit 6-0
PMADR<14:8>: Specifies the Most Significant bits for Program Memory Address bits
Note 1:
Unimplemented, read as ‘1’.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 105
PIC12(L)F1571/2
REGISTER 10-5:
U-1
PMCON1: PROGRAM MEMORY CONTROL 1 REGISTER
R/W-0/0
(1)
—
CFGS
R/W-0/0
R/W/HC-0/0 R/W/HC-x/q(2)
(3)
LWLO
FREE
WRERR
R/W-0/0
R/S/HC-0/0
R/S/HC-0/0
WREN
WR
RD
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
S = Bit can only be set
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
HC = Hardware Clearable bit
bit 7
Unimplemented: Read as ‘1’(1)
bit 6
CFGS: Configuration Select bit
1 = Accesses Configuration, User ID and Device ID registers
0 = Accesses Flash program memory
bit 5
LWLO: Load Write Latches Only bit(3)
1 = Only the addressed program memory write latch is loaded/updated on the next WR command
0 = The addressed program memory write latch is loaded/updated and a write of all program memory
write latches will be initiated on the next WR command
bit 4
FREE: Program Flash Erase Enable bit
1 = Performs an erase operation on the next WR command (hardware cleared upon completion)
0 = Performs a write operation on the next WR command
bit 3
WRERR: Program/Erase Error Flag bit(2)
1 = Condition indicates an improper program or erase sequence attempt or termination (bit is set
automatically on any set attempt (writes ‘1’) of the WR bit)
0 = The program or erase operation completed normally
bit 2
WREN: Program/Erase Enable bit
1 = Allows program/erase cycles
0 = Inhibits programming/erasing of program Flash
bit 1
WR: Write Control bit
1 = Initiates a program Flash program/erase operation
The operation is self-timed and the bit is cleared by hardware once operation is complete. The WR
bit can only be set (not cleared) in software.
0 = Program/erase operation to the Flash is complete and inactive
bit 0
RD: Read Control bit
1 = Initiates a program Flash read
Read takes one cycle. RD is cleared in hardware. The RD bit can only be set (not cleared) in
software.
0 = Does not initiate a program Flash read
Note 1:
2:
3:
Unimplemented bit, read as ‘1’.
The WRERR bit is automatically set by hardware when a program memory write or erase operation is
started (WR = 1).
The LWLO bit is ignored during a program memory erase operation (FREE = 1).
DS40001723D-page 106
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
REGISTER 10-6:
W-0/0
PMCON2: PROGRAM MEMORY CONTROL 2 REGISTER
W-0/0
W-0/0
W-0/0
W-0/0
W-0/0
W-0/0
W-0/0
Program Memory Control Register 2
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
S = Bit can only be set
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-0
Flash Memory Unlock Pattern bits
To unlock writes, a 55h must be written first, followed by an AAh, before setting the WR bit of the
PMCON1 register. The value written to this register is used to unlock the writes. There are specific
timing requirements on these writes.
TABLE 10-3:
Name
SUMMARY OF REGISTERS ASSOCIATED WITH FLASH PROGRAM MEMORY
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Register
on Page
INTCON
GIE
PEIE
TMR0IE
INTE
IOCIE
TMR0IF
INTF
IOCIF
74
PMCON1
—(1)
CFGS
LWLO
FREE
WRERR
WREN
WR
RD
106
PMCON2
Program Memory Control Register 2
107
PMADRL
PMADRL<7:0>
105
PMADRH
—(1)
PMADRH<6:0>
PMDATL
105
PMDATL<7:0>
—
PMDATH
—
104
PMDATH<5:0>
104
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used by Flash program memory.
Note 1: Unimplemented, read as ‘1’.
TABLE 10-4:
Name
CONFIG1
CONFIG2
SUMMARY OF CONFIGURATION WORD WITH FLASH PROGRAM MEMORY
Bits
Bit -/7
Bit -/6
Bit 13/5
Bit 12/4
Bit 11/3
13:8
—
—
—
—
CLKOUTEN
7:0
CP
MCLRE
PWRTE
13:8
—
—
LVP
DEBUG
LPBOR
BORV
7:0
—
—
—
—
—
—
WDTE<1:0>
Bit 10/2
Bit 9/1
Bit 8/0
BOREN<1:0>
—
—
FOSC<1:0>
STVREN
PLLEN
WRT<1:0>
Register
on Page
42
43
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used by Flash program memory.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 107
PIC12(L)F1571/2
NOTES:
DS40001723D-page 108
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
11.0
I/O PORTS
Each port has three standard registers for its operation.
These registers are:
• TRISx registers (Data Direction)
• PORTx registers (reads the levels on the pins of
the device)
• LATx registers (Output Latch)
• INLVLx (Input Level Control)
• ODCONx registers (Open-Drain Control)
• SLRCONx registers (Slew Rate Control)
Ports that support analog inputs have an associated
ANSELx register. When an ANSELx bit is set, the
digital input buffer associated with that bit is disabled.
Disabling the input buffer prevents analog signal levels
on the pin between a logic high and low from causing
excessive current in the logic input circuitry. A
simplified model of a generic I/O port, without the
interfaces to other peripherals, is shown in Figure 11-1.
FIGURE 11-1:
GENERIC I/O PORT
OPERATION
Rev. 10-000052A
7/30/2013
Some ports may have one or more of the following
additional registers. These registers are:
Read LATx
• ANSELx (Analog Select)
• WPUx (Weak Pull-up)
TRISx
In general, when a peripheral is enabled on a port pin,
that pin cannot be used as a general purpose output.
However, the pin can still be read.
D
Q
Write LATx
Write PORTx
VDD
CK
PORT AVAILABILITY PER
DEVICE
Device
PORTA
TABLE 11-1:
Data Register
Data bus
I/O pin
Read PORTx
To digital peripherals
PIC12(L)F1571
●
ANSELx
PIC12(L)F1572
●
To analog peripherals
The Data Latch (LATx registers) is useful for
Read-Modify-Write operations on the value that the I/O
pins are driving.
VSS
A write operation to the LATx register has the same
effect as a write to the corresponding PORTx register.
A read of the LATx register reads the values held in the
I/O port latches, while a read of the PORTx register
reads the actual I/O pin value.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 109
PIC12(L)F1571/2
11.1
Alternate Pin Function
The Alternate Pin Function Control (APFCON) register
is used to steer specific peripheral input and output
functions between different pins. The APFCON register
is shown in Register 11-1. For this device family, the
following functions can be moved between different
pins.
•
•
•
•
•
•
These bits have no effect on the values of any TRISx
register. PORTx and TRISx overrides will be routed to
the correct pin. The unselected pin will be unaffected.
RX/DT
TX/CK
CWGOUTA
CWGOUTB
PWM2
PWM1
11.2
Register Definitions: Alternate Pin Function Control
REGISTER 11-1:
APFCON: ALTERNATE PIN FUNCTION CONTROL REGISTER
R/W-0/0
R/W-0/0
R/W-0/0
U-0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
RXDTSEL
CWGASEL
CWGBSEL
—
T1GSEL
TXCKSEL
P2SEL
P1SEL
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
RXDTSEL: Pin Selection bit
1 = RX/DT function is on RA5
0 = RX/DT function is on RA1
bit 6
CWGASEL: Pin Selection bit
1 = CWGOUTA function is on RA5
0 = CWGOUTA function is on RA2
bit 5
CWGBSEL: Pin Selection bit
1 = CWGOUTB function is on RA4
0 = CWGOUTB function is on RA0
bit 4
Unimplemented: Read as ‘0’
bit 3
T1GSEL: Pin Selection bit
1 = T1G function is on RA3
0 = T1G function is on RA4
bit 2
TXCKSEL: Pin Selection bit
1 = TX/CK function is on RA4
0 = TX/CK function is on RA0
bit 1
P2SEL: Pin Selection bit
1 = PWM2 function is on RA4
0 = PWM2 function is on RA0
bit 0
P1SEL: Pin Selection bit
1 = PWM1 function is on RA5
0 = PWM1 function is on RA1
DS40001723D-page 110
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
11.3
11.3.1
PORTA Registers
DATA REGISTER
PORTA is a 6-bit wide, bidirectional port. The
corresponding Data Direction register is TRISA
(Register 11-3). Setting a TRISA bit (= 1) will make the
corresponding PORTA pin an input (i.e., disable the
output driver). Clearing a TRISA bit (= 0) will make the
corresponding PORTA pin an output (i.e., enables
output driver and puts the contents of the output latch
on the selected pin). The exception is RA3, which is
input-only and its TRISA bit will always read as ‘1’.
Example 11-1 shows how to initialize an I/O port.
Reading the PORTA register (Register 11-2) reads the
status of the pins, whereas writing to it will write to the
PORT latch. All write operations are Read-Modify-Write
operations. Therefore, a write to a port implies that the
port pins are read, this value is modified and then
written to the Port Data Latch (LATA).
11.3.2
DIRECTION CONTROL
The TRISA register (Register 11-3) controls the
PORTA pin output drivers, even when they are being
used as analog inputs. The user should ensure the bits
in the TRISA register are maintained set when using
them as analog inputs. I/O pins configured as analog
input always read ‘0’.
11.3.3
OPEN-DRAIN CONTROL
The ODCONA register (Register 11-7) controls the
open-drain feature of the port. Open-drain operation is
independently selected for each pin. When an
ODCONA bit is set, the corresponding port output
becomes an open-drain driver capable of sinking
current only. When an ODCONA bit is cleared, the
corresponding port output pin is the standard push-pull
drive capable of sourcing and sinking current.
11.3.4
SLEW RATE CONTROL
The SLRCONA register (Register 11-8) controls the
slew rate option for each port pin. Slew rate control is
independently selectable for each port pin. When an
SLRCONA bit is set, the corresponding port pin drive is
slew rate limited. When an SLRCONA bit is cleared,
the corresponding port pin drive slews at the maximum
rate possible.
 2013-2015 Microchip Technology Inc.
11.3.5
INPUT THRESHOLD CONTROL
The INLVLA register (Register 11-9) controls the input
voltage threshold for each of the available PORTA input
pins. A selection between the Schmitt Trigger CMOS or
the TTL compatible thresholds is available. The input
threshold is important in determining the value of a
read of the PORTA register and also the level at which
an Interrupt-On-Change occurs, if that feature is
enabled. See Section 26.3 “DC Characteristics” for
more information on threshold levels.
Note:
11.3.6
Changing the input threshold selection
should be performed while all peripheral
modules are disabled. Changing the
threshold level during the time a module is
active may inadvertently generate a transition associated with an input pin, regardless
of the actual voltage level on that pin.
ANALOG CONTROL
The ANSELA register (Register 11-5) is used to
configure the Input mode of an I/O pin to analog.
Setting the appropriate ANSELA bit high will cause all
digital reads on the pin to be read as ‘0’ and allow
analog functions on the pin to operate correctly.
The state of the ANSELA bits has no effect on digital output functions. A pin with TRIS clear and ANSELA set will
still operate as a digital output, but the Input mode will be
analog. This can cause unexpected behavior when
executing Read-Modify-Write instructions on the
affected port.
Note:
The ANSELA bits default to the Analog
mode after Reset. To use any pins as
digital general purpose or peripheral
inputs, the corresponding ANSELA bits
must be initialized to ‘0’ by user software.
EXAMPLE 11-1:
BANKSEL
CLRF
BANKSEL
CLRF
BANKSEL
CLRF
BANKSEL
MOVLW
MOVWF
INITIALIZING PORTA
PORTA
PORTA
LATA
LATA
ANSELA
ANSELA
TRISA
B'00111000'
TRISA
;
;Init PORTA
;Data Latch
;
;
;digital I/O
;
;Set RA<5:3> as inputs
;and set RA<2:0> as
;outputs
DS40001723D-page 111
PIC12(L)F1571/2
11.3.7
PORTA FUNCTIONS AND OUTPUT
PRIORITIES
Each PORTA pin is multiplexed with other functions. The
pins, their combined functions and their output priorities
are shown in Table 11-2.
TABLE 11-2:
RA0
ICSPDAT
CWG1B(3)
DAC1OUT
TX(2,3)
PWM2(3)
RA0
RA1
PWM1(3)
RA1
RA2
CWG1A
CWG1FLT
C1OUT
PWM3
RA2
RA3
None
RA4
CLKOUT
CWG1B
TX(2)
PWM2
RA4
RA5
CWG1A
PWM1
RA5
Note 1:
2:
3:
DS40001723D-page 112
Function Priority(1)
Pin Name
When multiple outputs are enabled, the actual pin
control goes to the peripheral with the highest priority.
Analog input functions, such as ADC and comparator
inputs, are not shown in the priority lists. These inputs
are active when the I/O pin is set for Analog mode using
the ANSELx registers. Digital output functions may
control the pin when it is in Analog mode with the
priority shown below in Table 11-2.
PORTA OUTPUT PRIORITY
Priority listed from highest to lowest.
PIC12(L)F1572 only.
Default pin (see APFCON register).
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
11.4
Register Definitions: PORTA
REGISTER 11-2:
PORTA: PORTA REGISTER
U-0
U-0
—
—
R/W-x/x
R/W-x/x
R-x/x
R/W-x/x
R/W-x/x
R/W-x/x
RA<5:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-6
Unimplemented: Read as ‘0’
bit 5-0
RA<5:0>: PORTA I/O Value bits(1)
1 = Port pin is > VIH
0 = Port pin is < VIL
Note 1:
Writes to PORTA are actually written to corresponding LATA register. Reads from the PORTA register are
the return of actual I/O pin values.
REGISTER 11-3:
TRISA: PORTA TRI-STATE REGISTER
U-0
U-0
—
—
R/W-1/1
R/W-1/1
TRISA<5:4>
U-1
—(1)
R/W-1/1
R/W-1/1
R/W-1/1
TRISA<2:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-6
Unimplemented: Read as ‘0’
bit 5-4
TRISA<5:4>: PORTA Tri-State Control bits
1 = PORTA pin configured as an input (tri-stated)
0 = PORTA pin configured as an output
bit 3
Unimplemented: Read as ‘1’(1)
bit 2-0
TRISA<2:0>: PORTA Tri-State Control bits
1 = PORTA pin configured as an input (tri-stated)
0 = PORTA pin configured as an output
Note 1:
Unimplemented, read as ‘1’.
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PIC12(L)F1571/2
REGISTER 11-4:
LATA: PORTA DATA LATCH REGISTER
U-0
U-0
—
—
R/W-x/u
R/W-x/u
U-0
LATA<5:4>(1)
R/W-x/u
R/W-x/u
R/W-x/u
LATA<2:0>(1)
—
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-6
Unimplemented: Read as ‘0’
bit 5-4
LATA<5:4>: RA<5:4> Output Latch Value bits(1)
bit 3
Unimplemented: Read as ‘0’
bit 2-0
LATA<2:0>: RA<2:0> Output Latch Value bits(1)
Note 1:
Writes to PORTA are actually written to corresponding LATA register. Reads from the PORTA register are
the return of actual I/O pin values.
REGISTER 11-5:
ANSELA: PORTA ANALOG SELECT REGISTER
U-0
U-0
U-0
R/W-1/1
U-0
—
—
—
ANSA4
—
R/W-1/1
R/W-1/1
R/W-1/1
ANSA<2:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-5
Unimplemented: Read as ‘0’
bit 4
ANSA4: Analog Select Between Analog or Digital Function on RA4 Pins (respectively) bit
1 = Analog input; pin is assigned as analog input, digital input buffer is disabled(1)
0 = Digital I/O; pin is assigned to port or digital special function
bit 3
Unimplemented: Read as ‘0’
bit 2-0
ANSA<2:0>: Analog Select Between Analog or Digital Function on RA<2:0> pins (respectively) bits
1 = Analog input; pin is assigned as analog input, digital input buffer is disabled(1)
0 = Digital I/O; pin is assigned to port or digital special function
Note 1:
When setting a pin to an analog input, the corresponding TRISx bit must be set to Input mode in order to
allow external control of the voltage on the pin.
DS40001723D-page 114
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
REGISTER 11-6:
U-0
WPUA: WEAK PULL-UP PORTA REGISTER
U-0
—
R/W-1/1
R/W-1/1
R/W-1/1
—
R/W-1/1
WPUA<5:0>
R/W-1/1
R/W-1/1
(1,2,3)
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-6
Unimplemented: Read as ‘0’
bit 5-0
WPUA<5:0>: Weak Pull-up Register bits(1,2,3)
1 = Pull-up is enabled
0 = Pull-up is disabled
Note 1:
2:
3:
Global WPUEN bit of the OPTION_REG register must be cleared for individual pull-ups to be enabled.
The weak pull-up device is automatically disabled if the pin is configured as an output.
For the WPUA3 bit, when MCLRE = 1, the weak pull-up is internally enabled, but not reported here.
REGISTER 11-7:
ODCONA: PORTA OPEN-DRAIN CONTROL REGISTER
U-0
U-0
—
—
R/W-0/0
R/W-0/0
ODA<5:4>
U-0
—
R/W-0/0
R/W-0/0
R/W-0/0
ODA<2:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-6
Unimplemented: Read as ‘0’
bit 5-4
ODA<5:4>: PORTA Open-Drain Enable bits
For RA<5:4> Pins, Respectively:
1 = Port pin operates as open-drain drive (sink current only)
0 = Port pin operates as standard push-pull drive (source and sink current)
bit 3
Unimplemented: Read as ‘0’
bit 2-0
ODA<2:0>: PORTA Open-Drain Enable bits
For RA<2:0> Pins, Respectively:
1 = Port pin operates as open-drain drive (sink current only)
0 = Port pin operates as standard push-pull drive (source and sink current)
 2013-2015 Microchip Technology Inc.
DS40001723D-page 115
PIC12(L)F1571/2
REGISTER 11-8:
SLRCONA: PORTA SLEW RATE CONTROL REGISTER
U-0
U-0
—
—
R/W-1/1
R/W-1/1
U-0
SLRA<5:4>
R/W-1/1
—
R/W-1/1
R/W-1/1
SLRA<2:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-6
Unimplemented: Read as ‘0’
bit 5-4
SLRA<5:4>: PORTA Slew Rate Enable bits
For RA<5:4> Pins, Respectively:
1 = Port pin slew rate is limited
0 = Port pin slews at maximum rate
bit 3
Unimplemented: Read as ‘0’
bit 2-0
SLRA<2:0>: PORTA Slew Rate Enable bits
For RA<2:0> Pins, Respectively:
1 = Port pin slew rate is limited
0 = Port pin slews at maximum rate
REGISTER 11-9:
INLVLA: PORTA INPUT LEVEL CONTROL REGISTER
U-0
U-0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
—
—
INLVLA5
INLVLA4
INLVLA3
INLVLA2
INLVLA1
INLVLA0
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-6
Unimplemented: Read as ‘0’
bit 5-0
INLVLA<5:0>: PORTA Input Level Select bits
For RA<5:0> Pins, Respectively:
1 = ST input is used for PORT reads and Interrupt-On-Change
0 = TTL input is used for PORT reads and Interrupt-On-Change
DS40001723D-page 116
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
TABLE 11-3:
SUMMARY OF REGISTERS ASSOCIATED WITH PORTA
Name
ANSELA
APFCON
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
—
—
—
ANSA4
—
RXDTSEL CWGASEL CWGBSEL
—
Bit 2
Bit 1
Bit 0
ANSA<2:0>
T1GSEL TXCKSEL
P2SEL
Register
on Page
114
P1SEL
INLVLA<5:0>
110
INLVLA
—
—
LATA
—
—
LATA<5:4>
—
LATA<2:0>
114
ODCONA
—
—
ODA<5:4>
—
ODA<2:0>
115
PS<2:0>
157
WPUEN
INTEDG
PORTA
—
—
SLRCONA
—
—
SLRA<5:4>
—
SLRA<2:0>
116
TRISA
—
—
TRISA<5:4>
—(1)
TRISA<2:0>
113
WPUA
—
—
OPTION_REG
TMR0CS
TMR0SE
116
PSA
RA<5:0>
113
WPUA<5:0>
115
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used by PORTA.
Note 1: Unimplemented, read as ‘1’.
TABLE 11-4:
Name
CONFIG1
Bits
SUMMARY OF CONFIGURATION WORD WITH PORTA
Bit -/7
Bit -/6
Bit 13/5
Bit 12/4
Bit 11/3
IESO
CLKOUTEN
13:8
—
—
FCMEN
7:0
CP
MCLRE
PWRTE
WDTE<1:0>
Bit 10/2
Bit 9/1
BOREN<1:0>
Bit 8/0
—
FOSC<2:0>
Register
on Page
42
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used by PORTA.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 117
PIC12(L)F1571/2
NOTES:
DS40001723D-page 118
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
12.0
INTERRUPT-ON-CHANGE
The PORTA and PORTB pins can be configured to
operate as Interrupt-On-Change (IOC) pins. An interrupt
can be generated by detecting a signal that has either a
rising edge or a falling edge. Any individual port pin, or
combination of port pins, can be configured to generate
an interrupt. The Interrupt-On-Change module has the
following features:
•
•
•
•
Interrupt-On-Change enable (Master Switch)
Individual pin configuration
Rising and falling edge detection
Individual pin interrupt flags
Figure 12-1 is a block diagram of the IOC module.
12.1
Enabling the Module
12.3
Interrupt Flags
The IOCAFx and IOCBFx bits located in the IOCAF and
IOCBF registers, respectively, are status flags that
correspond to the Interrupt-On-Change pins of the
associated port. If an expected edge is detected on an
appropriately enabled pin, then the status flag for that pin
will be set, and an interrupt will be generated if the IOCIE
bit is set. The IOCIF bit of the INTCON register reflects
the status of all IOCAFx and IOCBFx bits.
12.4
Clearing Interrupt Flags
The individual status flags, (IOCAFx and IOCBFx bits),
can be cleared by resetting them to zero. If another edge
is detected during this clearing operation, the associated
status flag will be set at the end of the sequence,
regardless of the value actually being written.
To allow individual port pins to generate an interrupt, the
IOCIE bit of the INTCON register must be set. If the
IOCIE bit is disabled, the edge detection on the pin will
still occur, but an interrupt will not be generated.
In order to ensure that no detected edge is lost while
clearing flags, only AND operations masking out known
changed bits should be performed. The following
sequence is an example of what should be performed.
12.2
Individual Pin Configuration
EXAMPLE 12-1:
For each port pin, a rising edge detector and a falling
edge detector are present. To enable a pin to detect a
rising edge, the associated bit of the IOCxP register is
set. To enable a pin to detect a falling edge, the
associated bit of the IOCxN register is set.
MOVLW
XORWF
ANDWF
A pin can be configured to detect rising and falling
edges simultaneously by setting both associated bits of
the IOCxP and IOCxN registers, respectively.
12.5
CLEARING INTERRUPT
FLAGS (PORTA EXAMPLE)
0xff
IOCAF, W
IOCAF, F
Operation in Sleep
The Interrupt-On-Change interrupt sequence will wake
the device from Sleep mode, if the IOCIE bit is set.
If an edge is detected while in Sleep mode, the IOCxF
register will be updated prior to the first instruction
executed out of Sleep.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 119
PIC12(L)F1571/2
FIGURE 12-1:
INTERRUPT-ON-CHANGE BLOCK DIAGRAM (PORTA EXAMPLE)
Rev. 10-000 037A
6/2/201 4
IOCANx
D
Q
R
Q4Q1
edge
detect
RAx
IOCAPx
D
data bus =
0 or 1
Q
D
S
to data bus
IOCAFx
Q
write IOCAFx
R
IOCIE
Q2
IOC interrupt
to CPU core
from all other
IOCnFx individual
pin detectors
FOSC
Q1
Q1
Q2
Q2
Q2
Q3
Q3
Q4
Q4Q1
Q1
Q3
Q4
Q4Q1
DS40001723D-page 120
Q4
Q4Q1
Q4Q1
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
12.6
Register Definitions: Interrupt-On-Change Control
REGISTER 12-1:
IOCAP: INTERRUPT-ON-CHANGE PORTA POSITIVE EDGE REGISTER
U-0
U-0
—
—
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
IOCAP<5:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-6
Unimplemented: Read as ‘0’
bit 5-0
IOCAP<5:0>: Interrupt-On-Change PORTA Positive Edge Enable bits
1 = Interrupt-On-Change is enabled on the pin for a positive going edge; IOCAFx bit and IOCIF flag
will be set upon detecting an edge
0 = Interrupt-On-Change is disabled for the associated pin
REGISTER 12-2:
IOCAN: INTERRUPT-ON-CHANGE PORTA NEGATIVE EDGE REGISTER
U-0
U-0
—
—
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
IOCAN<5:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-6
Unimplemented: Read as ‘0’
bit 5-0
IOCAN<5:0>: Interrupt-On-Change PORTA Negative Edge Enable bits
1 = Interrupt-On-Change is enabled on the pin for a negative going edge; IOCAFx bit and IOCIF flag
will be set upon detecting an edge.
0 = Interrupt-On-Change is disabled for the associated pin
 2013-2015 Microchip Technology Inc.
DS40001723D-page 121
PIC12(L)F1571/2
REGISTER 12-3:
IOCAF: INTERRUPT-ON-CHANGE PORTA FLAG REGISTER
U-0
U-0
—
—
R/W/HS-0/0 R/W/HS-0/0 R/W/HS-0/0
R/W/HS-0/0
R/W/HS-0/0
R/W/HS-0/0
IOCAF<5:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
HS - Bit is set in hardware
bit 7-6
Unimplemented: Read as ‘0’
bit 5-0
IOCAF<5:0>: Interrupt-On-Change PORTA Flag bits
1 = An enabled change was detected on the associated pin
Set when IOCAPx = 1 and a rising edge was detected on RAx, or when IOCANx = 1 and a falling
edge was detected on RAx.
0 = No change was detected or the user cleared the detected change
TABLE 12-1:
Name
SUMMARY OF REGISTERS ASSOCIATED WITH INTERRUPT-ON-CHANGE
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
ANSELA
—
—
—
ANSA4
—
INTCON
TMR0IE
INTE
IOCIE
Bit 2
Bit 1
Bit 0
ANSA<2:0>
GIE
PEIE
—
—
IOCAF<5:0>
122
IOCAN
—
—
IOCAN<5:0>
121
IOCAP
—
—
IOCAP<5:0>
121
TRISA
—
—
TRISA<5:4>
INTF
114
IOCAF
—(1)
TMR0IF
Register
on Page
IOCIF
TRISA<2:0>
74
113
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used by Interrupt-On-Change.
Note 1: Unimplemented, read as ‘1’.
DS40001723D-page 122
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
13.0
FIXED VOLTAGE REFERENCE
(FVR)
The Fixed Voltage Reference (FVR) is a stable voltage
reference, independent of VDD, with a nominal output
level (VFVR) of 1.024V. The output of the FVR can be
configured to supply a reference voltage to the
following:
• ADC input channel
• Comparator positive input
• Comparator negative input
The FVR can be enabled by setting the FVREN bit of
the FVRCON register.
13.1
The CDAFVR<1:0> bits of the FVRCON register are
used to enable and configure the gain amplifier settings
for the reference supplied to the comparator modules.
Reference Section 17.0 “Comparator Module” for
additional information.
To minimize current consumption when the FVR is
disabled, the FVR buffers should be turned off by
clearing the Buffer Gain Selection bits.
13.2
Independent Gain Amplifier
The output of the FVR supplied to the peripherals,
(listed above), is routed through a programmable gain
amplifier. Each amplifier can be programmed for a gain
of 1x, 2x or 4x, to produce the three possible voltage
levels.
FIGURE 13-1:
The ADFVR<1:0> bits of the FVRCON register are
used to enable and configure the gain amplifier settings
for the reference supplied to the ADC module. Reference Section 15.0 “Analog-to-Digital Converter
(ADC) Module” for additional information.
FVR Stabilization Period
The FVR can be enabled by setting the FVREN bit of
the FVRCON register.
When the Fixed Voltage Reference module is enabled, it
requires time for the reference and amplifier circuits to
stabilize. Once the circuits stabilize and are ready for use,
the FVRRDY bit of the FVRCON register will be set. See
the FVR Stabilization Period characterization graph,
Figure 27-21.
VOLTAGE REFERENCE BLOCK DIAGRAM
Rev. 10-000053A
8/6/2013
ADFVR<1:0>
CDAFVR<1:0>
FVREN
Note 1
2
1x
2x
4x
FVR_buffer1
(To ADC Module)
1x
2x
4x
FVR_buffer2
(To Comparators)
2
+
_
FVRRDY
Note 1: Any peripheral requiring the Fixed Voltage Reference (see Table 13-1).
 2013-2015 Microchip Technology Inc.
DS40001723D-page 123
PIC12(L)F1571/2
TABLE 13-1:
PERIPHERALS REQUIRING THE FIXED VOLTAGE REFERENCE (FVR)
Peripheral
HFINTOSC
BOR
LDO
Conditions
Description
FOSC<2:0> = 010 and
IRCF<3:0> = 000x
INTOSC is active and device is not in Sleep.
BOREN<1:0> = 11
BOR is always enabled.
BOREN<1:0> = 10 and BORFS = 1
BOR is disabled in Sleep mode, BOR Fast Start is enabled.
BOREN<1:0> = 01 and BORFS = 1
BOR under software control, BOR Fast Start is enabled.
All PIC12F1571/2 devices, when
VREGPM = 1 and not in Sleep
The device runs off of the Low-Power Regulator when in
Sleep mode.
DS40001723D-page 124
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
13.3
Register Definitions: FVR Control
REGISTER 13-1:
FVRCON: FIXED VOLTAGE REFERENCE CONTROL REGISTER
R/W-0/0
R-q/q
R/W-0/0
R/W-0/0
FVREN(1)
FVRRDY(2)
TSEN(3)
TSRNG(3)
R/W-0/0
R/W-0/0
R/W-0/0
CDAFVR<1:0>(1)
R/W-0/0
ADFVR<1:0>(1)
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
q = Value depends on condition
bit 7
FVREN: Fixed Voltage Reference Enable bit(1)
1 = Fixed Voltage Reference is enabled
0 = Fixed Voltage Reference is disabled
bit 6
FVRRDY: Fixed Voltage Reference Ready Flag bit(2)
1 = Fixed Voltage Reference output is ready for use
0 = Fixed Voltage Reference output is not ready or not enabled
bit 5
TSEN: Temperature Indicator Enable bit(3)
1 = Temperature indicator is enabled
0 = Temperature indicator is disabled
bit 4
TSRNG: Temperature Indicator Range Selection bit(3)
1 = VOUT = VDD – 4VT (High Range)
0 = VOUT = VDD – 2VT (Low Range)
bit 3-2
CDAFVR<1:0>: Comparator FVR Buffer Gain Selection bits(1)
11 = Comparator FVR Buffer Gain is 4x, with output VCDAFVR = 4x VFVR(4)
10 = Comparator FVR Buffer Gain is 2x, with output VCDAFVR = 2x VFVR(4)
01 = Comparator FVR Buffer Gain is 1x, with output VCDAFVR = 1x VFVR
00 = Comparator FVR Buffer is off
bit 1-0
ADFVR<1:0>: ADC FVR Buffer Gain Selection bit(1)
11 = ADC FVR Buffer Gain is 4x, with output VADFVR = 4x VFVR(4)
10 = ADC FVR Buffer Gain is 2x, with output VADFVR = 2x VFVR(4)
01 = ADC FVR Buffer Gain is 1x, with output VADFVR = 1x VFVR
00 = ADC FVR Buffer is off
Note 1:
2:
3:
4:
To minimize current consumption when the FVR is disabled, the FVR buffers should be turned off by
clearing the Buffer Gain Selection bits.
FVRRDY is always ‘1’ for the PIC12F1571/2 devices.
See Section 14.0 “Temperature Indicator Module” for additional information.
Fixed Voltage Reference output cannot exceed VDD.
TABLE 13-2:
Name
FVRCON
SUMMARY OF REGISTERS ASSOCIATED WITH THE FIXED VOLTAGE REFERENCE
Bit 7
Bit 6
Bit 5
Bit 4
FVREN
FVRRDY
TSEN
TSRNG
 2013-2015 Microchip Technology Inc.
Bit 3
Bit 2
CDAFVR>1:0>
Bit 1
Bit 0
ADFVR<1:0>
Register
on Page
125
DS40001723D-page 125
PIC12(L)F1571/2
NOTES:
DS40001723D-page 126
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
14.0
TEMPERATURE INDICATOR
MODULE
FIGURE 14-1:
This family of devices is equipped with a temperature
circuit designed to measure the operating temperature
of the silicon die. The circuit’s range of operating
temperature falls between -40°C and +85°C. The
output is a voltage that is proportional to the device
temperature. The output of the temperature indicator is
internally connected to the device ADC.
Rev. 10-000069A
7/31/2013
VDD
TSEN
The circuit may be used as a temperature threshold
detector or a more accurate temperature indicator,
depending on the level of calibration performed. A onepoint calibration allows the circuit to indicate a
temperature closely surrounding that point. A two-point
calibration allows the circuit to sense the entire range
of temperature more accurately. Reference Application
Note AN1333, “Use and Calibration of the Internal
Temperature Indicator” (DS00001333) for more details
regarding the calibration process.
14.1
TEMPERATURE CIRCUIT
DIAGRAM
TSRNG
VOUT
Temp. Indicator
To ADC
Circuit Operation
Figure 14-1 shows a simplified block diagram of the
temperature circuit. The proportional voltage output is
achieved by measuring the forward voltage drop across
multiple silicon junctions.
Equation 14-1 describes the output characteristics of
the temperature indicator.
EQUATION 14-1:
VOUT RANGES
High Range: VOUT = VDD – 4 VT
Low Range: VOUT = VDD – 2 VT
The temperature sense circuit is integrated with the
Fixed Voltage Reference (FVR) module. See
Section 13.0 “Fixed Voltage Reference (FVR)” for
more information.
The circuit is enabled by setting the TSEN bit of the
FVRCON register. When disabled, the circuit draws no
current.
14.2
Minimum Operating VDD
When the temperature circuit is operated in low range,
the device may be operated at any operating voltage
that is within specifications.
When the temperature circuit is operated in high range,
the device operating voltage, VDD, must be high
enough to ensure that the temperature circuit is
correctly biased.
Table 14-1 shows the recommended minimum VDD vs.
range setting.
TABLE 14-1:
RECOMMENDED VDD VS.
RANGE
Min. VDD, TSRNG = 1
Min. VDD, TSRNG = 0
3.6V
1.8V
14.3
Temperature Output
The circuit operates in either high or low range. The high
range, selected by setting the TSRNG bit of the
FVRCON register, provides a wider output voltage. This
provides more resolution over the temperature range,
but may be less consistent from part to part. This range
requires a higher bias voltage to operate and thus, a
higher VDD is needed.
The output of the circuit is measured using the
internal Analog-to-Digital Converter. A channel is
reserved for the temperature circuit output. Refer to
Section 15.0 “Analog-to-Digital Converter (ADC)
Module” for detailed information.
The low range is selected by clearing the TSRNG bit of
the FVRCON register. The low range generates a lower
voltage drop and thus, a lower bias voltage is needed
to operate the circuit. The low range is provided for
low-voltage operation.
To ensure accurate temperature measurements, the
user must wait at least 200 s after the ADC input
multiplexer is connected to the temperature indicator
output before the conversion is performed. In addition,
the user must wait 200 s between sequential
conversions of the temperature indicator output.
 2013-2015 Microchip Technology Inc.
14.4
ADC Acquisition Time
DS40001723D-page 127
PIC12(L)F1571/2
TABLE 14-2:
Name
FVRCON
SUMMARY OF REGISTERS ASSOCIATED WITH THE TEMPERATURE INDICATOR
Bit 7
Bit 6
Bit 5
Bit 4
FVREN
FVRRDY
TSEN
TSRNG
Bit 3
Bit 2
CDAFVR<1:0>
Bit 1
Bit 0
ADFVR<1:0>
Register
on Page
118
Legend: Shaded cells are unused by the temperature indicator module.
DS40001723D-page 128
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
15.0
ANALOG-TO-DIGITAL
CONVERTER (ADC) MODULE
The ADC voltage reference is software selectable to be
either internally generated or externally supplied.
The Analog-to-Digital Converter (ADC) allows
conversion of an analog input signal to a 10-bit binary
representation of that signal. This device uses analog
inputs, which are multiplexed into a single sample and
hold circuit. The output of the sample and hold is
connected to the input of the converter. The converter
generates a 10-bit binary result via successive
approximation and stores the conversion result into the
ADC result registers (ADRESH:ADRESL register pair).
Figure 15-1 shows the block diagram of the ADC.
FIGURE 15-1:
The ADC can generate an interrupt upon completion of
a conversion. This interrupt can be used to wake-up the
device from Sleep.
ADC BLOCK DIAGRAM
VDD
ADPREF
Rev. 10-000033A
7/30/2013
Positive
Reference
Select
VDD
VREF+ pin
External
Channel
Inputs
ANa
VRNEG VRPOS
.
.
.
ADC_clk
sampled
input
ANz
Internal
Channel
Inputs
ADCS<2:0>
VSS
AN0
ADC
Clock
Select
FOSC/n Fosc
Divider
FRC
FOSC
FRC
Temp Indicator
DACx_output
ADC CLOCK SOURCE
FVR_buffer1
ADC
Sample Circuit
CHS<4:0>
ADFM
set bit ADIF
Write to bit
GO/DONE
10-bit Result
GO/DONE
Q1
Q4
16
start
ADRESH
Q2
TRIGSEL<3:0>
10
complete
ADRESL
Enable
Trigger Select
ADON
. . .
VSS
Trigger Sources
AUTO CONVERSION
TRIGGER
 2013-2015 Microchip Technology Inc.
DS40001723D-page 129
PIC12(L)F1571/2
15.1
ADC Configuration
When configuring and using the ADC the following
functions must be considered:
•
•
•
•
•
•
Port configuration
Channel selection
ADC voltage reference selection
ADC conversion clock source
Interrupt control
Result formatting
15.1.1
PORT CONFIGURATION
The ADC can be used to convert both analog and
digital signals. When converting analog signals, the I/O
pin should be configured for analog by setting the
associated TRISx and ANSELx bits. Refer to
Section 11.0 “I/O Ports” for more information.
Note:
15.1.2
Analog voltages on any pin that is defined
as a digital input may cause the input
buffer to conduct excess current.
CHANNEL SELECTION
There are 7 channel selections available:
•
•
•
•
AN<3:0> pins
Temperature Indicator
DAC1_output
FVR_buffer1
15.1.4
CONVERSION CLOCK
The source of the conversion clock is software-selectable
via the ADCSx bits of the ADCON1 register. There are
seven possible clock options:
•
•
•
•
•
•
•
FOSC/2
FOSC/4
FOSC/8
FOSC/16
FOSC/32
FOSC/64
FRC (internal Fast RC oscillator)
The time to complete one bit conversion is defined as
TAD. One full 10-bit conversion requires 11.5 TAD
periods, as shown in Figure 15-2.
For correct conversion, the appropriate TAD specification
must be met. Refer to the ADC conversion requirements
in Section 26.0 “Electrical Specifications” for more
information. Table 15-1 gives examples of appropriate
ADC clock selections.
Note:
Unless using the FRC, any changes in the
system clock frequency will change the
ADC clock frequency, which may
adversely affect the ADC result.
The CHS bits of the ADCON0 register determine which
channel is connected to the sample and hold circuit.
When changing channels, a delay (TACQ) is required
before starting the next conversion. Refer to
Section 15.2.6 “ADC Conversion Procedure” for
more information.
15.1.3
ADC VOLTAGE REFERENCE
The ADC module uses a positive and a negative
voltage reference. The positive reference is labeled
ref+ and the negative reference is labeled ref-.
The positive voltage reference (ref+) is selected by the
ADPREFx bits in the ADCON1 register. The positive
voltage reference source can be:
• VREF+ pin
• VDD
The negative voltage reference (ref-) source is:
• VSS
DS40001723D-page 130
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
TABLE 15-1:
ADC CLOCK PERIOD (TAD) VS. DEVICE OPERATING FREQUENCIES
ADC Clock Period (TAD)
ADC
Clock
Source
Device Frequency (FOSC)
ADCS<2:0>
20 MHz
16 MHz
8 MHz
4 MHz
1 MHz
Fosc/2
000
100 ns
125 ns
250 ns
500 ns
2.0 s
Fosc/4
100
200 ns
250 ns
500 ns
1.0 s
4.0 s
Fosc/8
001
400 ns
500 ns
1.0 s
2.0 s
8.0 s
Fosc/16
101
800 ns
1.0 s
2.0 s
4.0 s
16.0 s
Fosc/32
010
1.6 s
2.0 s
4.0 s
8.0 s
32.0 s
Fosc/64
110
3.2 s
4.0 s
8.0 s
16.0 s
64.0 s
FRC
x11
1.0-6.0 s
1.0-6.0 s
1.0-6.0 s
1.0-6.0 s
1.0-6.0 s
Legend: Shaded cells are outside of recommended range.
Note:
The TAD period when using the FRC clock source can fall within a specified range (see TAD parameter).
The TAD period when using the FOSC-based clock source can be configured for a more precise TAD period.
However, the FRC clock source must be used when conversions are to be performed with the device in
Sleep mode.
FIGURE 15-2:
ANALOG-TO-DIGITAL CONVERSION TAD CYCLES
Rev. 10-000035A
7/30/2013
TAD1
TAD2
TAD3
TAD4
TAD5
TAD6
TAD7
TAD8
TAD9
TAD10
TAD11
b9
b8
b7
b6
b5
b4
b3
b2
b1
b0
THCD
Conversion Starts
TACQ
Holding capacitor disconnected
from analog input (THCD).
Set GO bit
On the following cycle:
ADRESH:ADRESL is loaded,
GO bit is cleared,
ADIF bit is set,
holding capacitor is reconnected to analog input.
Enable ADC (ADON bit)
and
Select channel (ACS bits)
 2013-2015 Microchip Technology Inc.
DS40001723D-page 131
PIC12(L)F1571/2
15.1.5
INTERRUPTS
15.1.6
The ADC module allows for the ability to generate an
interrupt upon completion of an Analog-to-Digital
conversion. The ADC Interrupt Flag is the ADIF bit in
the PIR1 register. The ADC Interrupt Enable is the
ADIE bit in the PIE1 register. The ADIF bit must be
cleared in software.
RESULT FORMATTING
The 10-bit ADC conversion result can be supplied in
two formats, left justified or right justified. The ADFM bit
of the ADCON1 register controls the output format.
Figure 15-3 shows the two output formats.
Note 1: The ADIF bit is set at the completion of
every conversion, regardless of whether
or not the ADC interrupt is enabled.
2: The ADC operates during Sleep only
when the FRC oscillator is selected.
This interrupt can be generated while the device is
operating or while in Sleep. If the device is in Sleep, the
interrupt will wake-up the device. Upon waking from
Sleep, the next instruction following the SLEEP instruction is always executed. If the user is attempting to
wake-up from Sleep and resume in-line code execution, the ADIE bit of the PIE1 register and the PEIE bit
of the INTCON register must both be set, and the GIE
bit of the INTCON register must be cleared. If all three
of these bits are set, the execution will switch to the
Interrupt Service Routine.
FIGURE 15-3:
10-BIT ADC CONVERSION RESULT FORMAT
Rev. 10-000054A
7/30/2013
ADRESH
ADRESL
(ADFM = 0) MSB
LSB
bit 7
bit 0
bit 7
10-bit ADC Result
(ADFM = 1)
bit 0
Unimplemented: Read as ‘0’
MSB
bit 7
Unimplemented: Read as ‘0’
DS40001723D-page 132
LSB
bit 0
bit 7
bit 0
10-bit ADC Result
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
15.2
15.2.1
ADC Operation
STARTING A CONVERSION
To enable the ADC module, the ADON bit of the
ADCON0 register must be set to a ‘1’. Setting the
GO/DONE bit of the ADCON0 register to a ‘1’ will start
the Analog-to-Digital conversion.
Note:
15.2.2
The GO/DONE bit should not be set in the
same instruction that turns on the ADC.
Refer to Section 15.2.6 “ADC Conversion
Procedure”.
COMPLETION OF A CONVERSION
When the conversion is complete, the ADC module will:
• Clear the GO/DONE bit
• Set the ADIF Interrupt Flag bit
• Update the ADRESH and ADRESL registers with
new conversion result
15.2.3
TERMINATING A CONVERSION
15.2.5
The auto-conversion trigger allows periodic ADC
measurements without software intervention. When a
rising edge of the selected source occurs, the
GO/DONE bit is set by hardware.
The auto-conversion trigger source is selected with the
TRIGSEL<3:0> bits of the ADCON2 register.
Using the auto-conversion trigger does not assure
proper ADC timing. It is the user’s responsibility to
ensure that the ADC timing requirements are met.
The PWM module can trigger the ADC in two ways,
directly through the PWMx_OFx_match or through the
interrupts generated by all four match signals. See
Section 22.0 “16-Bit Pulse-Width Modulation (PWM)
Module”. If the interrupts are chosen, each enabled
interrupt in PWMxINTE will trigger a conversion. Refer
to Figure 15-4 for more information.
See Table 15-2 for auto-conversion sources.
FIGURE 15-4:
If a conversion must be terminated before completion,
the GO/DONE bit can be cleared in software. The
ADRESH and ADRESL registers will be updated with
the partially complete Analog-to-Digital conversion
sample. Incomplete bits will match the last bit
converted.
Note:
15.2.4
The ADC module can operate during Sleep. This
requires the ADC clock source to be set to the FRC
option. Performing the ADC conversion during Sleep
can reduce system noise. If the ADC interrupt is
enabled, the device will wake-up from Sleep when the
conversion completes. If the ADC interrupt is disabled,
the ADC module is turned off after the conversion
completes, although the ADON bit remains set.
When the ADC clock source is something other than
FRC, a SLEEP instruction causes the present conversion to be aborted and the ADC module is turned off,
although the ADON bit remains set.
 2013-2015 Microchip Technology Inc.
16-BIT PWM INTERRUPT
BLOCK DIAGRAM
Rev. 10-000154A
10/24/2013
OFx_match
PWMxOFIE
PHx_match
PWMxPHIE
A device Reset forces all registers to their
Reset state. Thus, the ADC module is
turned off and any pending conversion is
terminated.
ADC OPERATION DURING SLEEP
AUTO-CONVERSION TRIGGER
PWMx_interrupt
DCx_match
PWMxDCIE
PRx_match
PWMxPRIE
TABLE 15-2:
AUTO-CONVERSION
SOURCES
Source Peripheral
Signal Name
Timer0
T0_overflow
Timer1
T1_overflow
Timer2
T2_match
Comparator C1
C1OUT_sync
PWM1
PWM1_OF_match
PWM1
PWM1_interrupt
PWM2
PWM2_OF_match
PWM2
PWM2_interrupt
PWM3
PWM3_OF_match
PWM3
PWM3_interrupt
DS40001723D-page 133
PIC12(L)F1571/2
15.2.6
ADC CONVERSION PROCEDURE
This is an example procedure for using the ADC to
perform an Analog-to-Digital conversion:
1.
2.
3.
4.
5.
6.
7.
8.
Configure port:
• Disable pin output driver (refer to the
TRISx register)
• Configure pin as analog (refer to the
ANSELx register)
• Disable weak pull-ups either globally (refer to
the OPTION_REG register) or individually
(refer to the appropriate WPUx register)
Configure the ADC module:
• Select ADC conversion clock
• Configure voltage reference
• Select ADC input channel
• Turn on ADC module
Configure ADC interrupt (optional):
• Clear ADC interrupt flag
• Enable ADC interrupt
• Enable peripheral interrupt
• Enable global interrupt(1)
Wait the required acquisition time.(2)
Start conversion by setting the GO/DONE bit.
Wait for ADC conversion to complete by one of
the following:
• Polling the GO/DONE bit
• Waiting for the ADC interrupt (interrupts
enabled)
Read ADC result.
Clear the ADC interrupt flag (required if interrupt
is enabled).
EXAMPLE 15-1:
ADC CONVERSION
;This code block configures the ADC
;for polling, Vdd and Vss references, FRC
;oscillator and AN0 input.
;
;Conversion start & polling for completion
; are included.
;
BANKSEL
ADCON1
;
MOVLW
B’11110000’ ;Right justify, FRC
;oscillator
MOVWF
ADCON1
;Vdd and Vss Vref+
BANKSEL
TRISA
;
BSF
TRISA,0
;Set RA0 to input
BANKSEL
ANSEL
;
BSF
ANSEL,0
;Set RA0 to analog
BANKSEL
WPUA
BCF
WPUA,0
;Disable weak
;pull-up on RA0
BANKSEL
ADCON0
;
MOVLW
B’00000001’ ;Select channel AN0
MOVWF
ADCON0
;Turn ADC On
CALL
SampleTime
;Acquisiton delay
BSF
ADCON0,ADGO ;Start conversion
BTFSC
ADCON0,ADGO ;Is conversion done?
GOTO
$-1
;No, test again
BANKSEL
ADRESH
;
MOVF
ADRESH,W
;Read upper 2 bits
MOVWF
RESULTHI
;store in GPR space
BANKSEL
ADRESL
;
MOVF
ADRESL,W
;Read lower 8 bits
MOVWF
RESULTLO
;Store in GPR space
Note 1: The global interrupt can be disabled if the
user is attempting to wake-up from Sleep
and resume in-line code execution.
2: Refer to Section 15.4 “ADC Acquisition
Requirements”.
DS40001723D-page 134
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PIC12(L)F1571/2
15.3
Register Definitions: ADC Control
REGISTER 15-1:
U-0
ADCON0: ADC CONTROL REGISTER 0
R/W-0/0
R/W-0/0
—
R/W-0/0
R/W-0/0
CHS<4:0>
R/W-0/0
R/W-0/0
R/W-0/0
GO/DONE
ADON
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
Unimplemented: Read as ‘0’
bit 6-2
CHS<4:0>: Analog Channel Select bits
00000 = AN0
00001 = AN1
00010 = AN2
00011 = AN3
00100 = Reserved; no channel connected
•
•
•
11100 = Reserved; no channel connected
11101 = Temperature indicator(1)
11110 = DAC (Digital-to-Analog Converter)(2)
11111 = FVR (Fixed Voltage Reference) Buffer 1 output(3)
bit 1
GO/DONE: ADC Conversion Status bit
1 = ADC conversion cycle is in progress
Setting this bit starts an ADC conversion cycle. This bit is automatically cleared by hardware when
the ADC conversion has completed.
0 = ADC conversion completed/not in progress
bit 0
ADON: ADC Enable bit
1 = ADC is enabled
0 = ADC is disabled and consumes no operating current
Note 1:
2:
3:
See Section 14.0 “Temperature Indicator Module” for more information.
See Section 16.0 “5-Bit Digital-to-Analog Converter (DAC) Module” for more information.
See Section 13.0 “Fixed Voltage Reference (FVR)” for more information.
 2013-2015 Microchip Technology Inc.
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PIC12(L)F1571/2
REGISTER 15-2:
R/W-0/0
ADCON1: ADC CONTROL REGISTER 1
R/W-0/0
ADFM
R/W-0/0
R/W-0/0
ADCS<2:0>
U-0
U-0
—
—
R/W-0/0
bit 7
R/W-0/0
ADPREF<1:0>
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
ADFM: ADC Result Format Select bit
1 = Right justified; six Most Significant bits of ADRESH are set to ‘0’ when the conversion result is loaded
0 = Left justified; six Least Significant bits of ADRESL are set to ‘0’ when the conversion result is loaded
bit 6-4
ADCS<2:0>: ADC Conversion Clock Select bits
000 = FOSC/2
001 = FOSC/8
010 = FOSC/32
011 = FRC (clock supplied from an internal RC oscillator)
100 = FOSC/4
101 = FOSC/16
110 = FOSC/64
111 = FRC (clock supplied from an internal RC oscillator)
bit 3-2
Unimplemented: Read as ‘0’
bit 1-0
ADPREF<1:0>: ADC Positive Voltage Reference Configuration bits
00 = VRPOS is connected to VDD
01 = Reserved
10 = VRPOS is connected to external VREF+ pin(1)
11 = VRPOS is connected to internal Fixed Voltage Reference (FVR)
Note 1:
When selecting the VREF+ pin as the source of the positive reference, be aware that a minimum voltage
specification exists. See Section 26.0 “Electrical Specifications” for details.
DS40001723D-page 136
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
REGISTER 15-3:
R/W-0/0
ADCON2: ADC CONTROL REGISTER 2
R/W-0/0
R/W-0/0
TRIGSEL<3:0>
R/W-0/0
(1)
U-0
U-0
U-0
U-0
—
—
—
—
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-4
TRIGSEL<3:0>: Auto-Conversion Trigger Selection bits(1)
0000 = No auto-conversion trigger selected
0001 = PWM1 – PWM1_interrupt
0010 = PWM2 – PWM2_interrupt
0011 = Timer0 – T0_overflow(2)
0100 = Timer1 – T1_overflow(2)
0101 = Timer2 – T2_match
0110 = Comparator C1 – C1OUT_sync
0111 = PWM3 – PWM3_interrupt
1000 = PWM1 – PWM1_OF1_match
1001 = PWM2 – PWM2_OF2_match
1010 = PWM3 – PWM3_OF3_match
1011 = Reserved
1100 = Reserved
1101 = Reserved
1110 = Reserved
1111 = Reserved
bit 3-0
Unimplemented: Read as ‘0’
Note 1:
2:
This is a rising edge sensitive input for all sources.
Signal also sets its corresponding interrupt flag.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 137
PIC12(L)F1571/2
REGISTER 15-4:
R/W-x/u
ADRESH: ADC RESULT REGISTER HIGH (ADRESH) ADFM = 0
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
ADRES<9:2>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-0
ADRES<9:2>: ADC Result Register bits
Upper eight bits of 10-bit conversion result.
REGISTER 15-5:
R/W-x/u
ADRESL: ADC RESULT REGISTER LOW (ADRESL) ADFM = 0
R/W-x/u
ADRES<1:0>
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
—
—
—
—
—
—
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-6
ADRES<1:0>: ADC Result Register bits
Lower two bits of 10-bit conversion result.
bit 5-0
Reserved: Do not use
DS40001723D-page 138
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
REGISTER 15-6:
ADRESH: ADC RESULT REGISTER HIGH (ADRESH) ADFM = 1
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
—
—
—
—
—
—
R/W-x/u
R/W-x/u
ADRES<9:8>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-2
Reserved: Do not use
bit 1-0
ADRES<9:8>: ADC Result Register bits
Upper two bits of 10-bit conversion result.
REGISTER 15-7:
R/W-x/u
ADRESL: ADC RESULT REGISTER LOW (ADRESL) ADFM = 1
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
ADRES<7:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-0
ADRES<7:0>: ADC Result Register bits
Lower eight bits of 10-bit conversion result.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 139
PIC12(L)F1571/2
15.4
ADC Acquisition Requirements
For the ADC to meet its specified accuracy, the Charge
Holding Capacitor (CHOLD) must be allowed to fully
charge to the input channel voltage level. The Analog
Input model is shown in Figure 15-5. The Source
Impedance (RS) and the internal Sampling Switch
Impedance (RSS) directly affect the time required to
charge the capacitor, CHOLD. The Sampling Switch
Impedance (RSS) varies over the device voltage (VDD);
refer to Figure 15-5. The maximum recommended
impedance for analog sources is 10 k. As the
EQUATION 15-1:
Assumptions:
Source Impedance is decreased, the acquisition time
may be decreased. After the analog input channel is
selected (or changed), an ADC acquisition must be
done before the conversion can be started. To calculate
the minimum acquisition time, Equation 15-1 may be
used. This equation assumes that 1/2 LSb error is used
(1,024 steps for the ADC). The 1/2 LSb error is the
maximum error allowed for the ADC to meet its
specified resolution.
ACQUISITION TIME EXAMPLE
Temperature = 50°C and external impedance of 10k  5.0V V DD
T ACQ = Amplifier Settling Time + Hold Capacitor Charging Time + Temperature Coefficient
= T AMP + T C + T COFF
= 2µs + T C +   Temperature - 25°C   0.05µs/°C  
The value for TC can be approximated with the following equations:
1
 = V CHOLD
V AP P LI ED  1 – -------------------------n+1


2
–1
;[1] VCHOLD charged to within 1/2 lsb
–TC
----------

RC
V AP P LI ED  1 – e  = V CHOLD


;[2] VCHOLD charge response to VAPPLIED
– Tc
---------

1
RC
 ;combining [1] and [2]
V AP P LI ED  1 – e  = V A PP LIE D  1 – -------------------------n
+
1




2
–1
Note: Where n = number of bits of the ADC.
Solving for TC:
T C = – C HOLD  R IC + R SS + R S  ln(1/2047)
= – 12.5pF  1k  + 7k  + 10k   ln(0.0004885)
= 1.715 µs
Therefore:
T AC Q = 2µs + 1.715 µs +   50°C- 25°C   0.05 µs/°C  
= 4.96µs
Note 1: The Reference Voltage (VRPOS) has no effect on the equation, since it cancels itself out.
2: The Charge Holding Capacitor (CHOLD) is not discharged after each conversion.
3: The maximum recommended impedance for analog sources is 10 k. This is required to meet the pin
leakage specification.
DS40001723D-page 140
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
FIGURE 15-5:
ANALOG INPUT MODEL
Rev. 10-000070B
8/5/2014
VDD
RS
Analog
Input pin
VT § 0.6V
RIC ” 1K
Sampling
switch
SS
RSS
ILEAKAGE(1)
VA
Legend: CHOLD
CPIN
ILEAKAGE
RIC
RSS
SS
VT
Note 1:
FIGURE 15-6:
CPIN
5pF
CHOLD = 12.5 pF
VT § 0.6V
Ref-
= Sample/Hold Capacitance
= Input Capacitance
= Leakage Current at the pin due to varies injunctions
= Interconnect Resistance
= Resistance of Sampling switch
= Sampling Switch
= Threshold Voltage
VDD
6V
5V
4V
3V
2V
RSS
5 6 7 8 9 10 11
Sampling Switch
(kŸ )
Refer to Section 26.0 “Electrical Specifications”.
ADC TRANSFER FUNCTION
Full-Scale Range
3FFh
3FEh
ADC Output Code
3FDh
3FCh
3FBh
03h
02h
01h
00h
Analog Input Voltage
0.5 LSB
Ref-
 2013-2015 Microchip Technology Inc.
Zero-Scale
Transition
1.5 LSB
Full-Scale
Transition
Ref+
DS40001723D-page 141
PIC12(L)F1571/2
TABLE 15-3:
Name
SUMMARY OF REGISTERS ASSOCIATED WITH ADC
Bit 7
ADCON0
—
ADCON1
ADFM
ADCON2
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
CHS<4:0>
ADCS<2:0>
TRIGSEL<3:0>
Bit 1
Bit 0
Register
on Page
GO/DONE
ADON
135
—
—
ADPREF<1:0>
136
—
—
—
137
—
ADRESH
ADC Result Register High
138, 139
ADRESL
ADC Result Register Low
138, 139
ANSELA
—
—
—
ANSA4
—
INTCON
GIE
PEIE
TMR0IE
INTE
IOCIE
TMR0IF
ANSA<2:0>
INTF
IOCIF
114
(2)
(2)
74
PIE1
TMR1GIE
ADIE
RCIE
TXIE
—
—
TMR2IE
TMR1IE
75
PIR1
TMR1GIF
ADIF
RCIF(2)
TXIF(2)
—
—
TMR2IF
TMR1IF
78
—
—
TRISA5
TRISA4
—(1)
FVREN
FVRRDY
TSEN
TSRNG
CDAFVR<1:0>
TRISA
FVRCON
TRISA<2:0>
ADFVR<1:0>
113
125
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used for the ADC module.
Note 1: Unimplemented, read as ‘1’.
2: PIC12(L)F1572 only.
DS40001723D-page 142
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
16.0
5-BIT DIGITAL-TO-ANALOG
CONVERTER (DAC) MODULE
The output of the DAC (DACx_output) can be selected
as a reference voltage to the following:
The Digital-to-Analog Converter supplies a variable
voltage reference, ratiometric with the input source,
with 32 selectable output levels.
• Comparator positive input
• ADC input channel
• DACxOUT1 pin
The positive input source (VSOURCE+) of the DAC can
be connected to the:
The Digital-to-Analog Converter (DAC) can be enabled
by setting the DACEN bit of the DACxCON0 register.
• External VREF+ pin
• VDD supply voltage
• FVR buffered output
The negative input source (VSOURCE-) of the DAC can
be connected to the:
• Vss
FIGURE 16-1:
DIGITAL-TO-ANALOG CONVERTER BLOCK DIAGRAM
Rev. 10-000026B
9/6/2013
VDD
00
01
VREF+
FVR_buffer2
10
Reserved
11
VSOURCE+
5
DACR<4:0>
R
DACPSS
R
DACEN
R
32-to-1 MUX
R
32
Steps
DACx_output
To Peripherals
R
R
DACxOUT1 (1)
DACOE1
R
VSS
VSOURCE-
Note 1: The unbuffered DACx_output is provided on the DACxOUT pin(s).
 2013-2015 Microchip Technology Inc.
DS40001723D-page 143
PIC12(L)F1571/2
16.1
Output Voltage Selection
The DAC has 32 voltage level ranges. The 32 levels
are set with the DACR<4:0> bits of the DACxCON1
register.
The DAC output voltage can be determined by using
Equation 16-1.
16.2
Ratiometric Output Level
The DAC output value is derived using a resistor ladder
with each end of the ladder tied to a positive and
negative voltage reference input source. If the voltage
of either input source fluctuates, a similar fluctuation will
result in the DAC output value.
The value of the individual resistors within the ladder
can be found in Table 26-16.
16.3
DAC Voltage Reference Output
The unbuffered DAC voltage can be output to the
DACxOUTn pin(s) by setting the respective DACOEn
bit(s) of the DACxCON0 register. Selecting the DAC
reference voltage for output on either DACxOUTn pin
automatically overrides the digital output buffer, the
weak pull-up and digital input threshold detector
functions of that pin.
EQUATION 16-1:
Reading the DACxOUTn pin when it has been
configured for DAC reference voltage output will
always return a ‘0’.
Note:
16.4
The unbuffered DAC output (DACxOUTn)
is not intended to drive an external load.
Operation During Sleep
When the device wakes up from Sleep through an
interrupt or a Watchdog Timer time-out, the contents of
the DACxCON0 register are not affected. To minimize
current consumption in Sleep mode, the voltage
reference should be disabled.
16.5
Effects of a Reset
A device Reset affects the following:
• DACx is disabled.
• DACX output voltage is removed from the
DACxOUTn pin(s).
• The DACR<4:0> range select bits are cleared.
DAC OUTPUT VOLTAGE
IF DACEN = 1
DACR  4:0 
DACx_output =   VSOURCE+ – VSOURCE-   ----------------------------+ VSOURCE5


2
Note:
See the DACxCON0 register for the available VSOURCE+ and VSOURCE- selections.
DS40001723D-page 144
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
16.6
Register Definitions: DAC Control
REGISTER 16-1:
DACxCON0: DACx VOLTAGE REFERENCE CONTROL REGISTER 0
R/W-0/0
U-0
R/W-0/0
U-0
DACEN
—
DACOE
—
R/W-0/0
R/W-0/0
U-0
U-0
—
—
DACPSS<1:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
DACEN: DAC Enable bit
1 = DACx is enabled
0 = DACx is disabled
bit 6
Unimplemented: Read as ‘0’
bit 5
DACOE: DAC Voltage Output Enable bit
1 = DACx voltage level is output on the DACxOUT1 pin
0 = DACx voltage level is disconnected from the DACxOUT1 pin
bit 4
Unimplemented: Read as ‘0’
bit 3-2
DACPSS<1:0>: DAC Positive Source Select bits
11 = Reserved
10 = FVR_buffer2
01 = VREF+ pin
00 = VDD
bit 1-0
Unimplemented: Read as ‘0’
REGISTER 16-2:
DACxCON1: DACx VOLTAGE REFERENCE CONTROL REGISTER 1
U-0
U-0
U-0
—
—
—
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
DACR<4:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-5
Unimplemented: Read as ‘0’
bit 4-0
DACR<4:0>: DAC Voltage Output Select bits
TABLE 16-1:
SUMMARY OF REGISTERS ASSOCIATED WITH THE DAC MODULE
Name
Bit 7
Bit 6
Bit 5
Bit 4
DACxCON0
DACEN
—
DACOE
—
DACxCON1
—
—
—
Bit 3
Bit 2
DACPSS<1:0>
DACR<4:0>
Bit 1
Bit 0
Register
on Page
—
—
145
145
Legend: — = Unimplemented location, read as ‘0’.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 145
PIC12(L)F1571/2
NOTES:
DS40001723D-page 146
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PIC12(L)F1571/2
17.0
COMPARATOR MODULE
17.1
Comparator Overview
Comparators are used to interface analog circuits to a
digital circuit by comparing two analog voltages and
providing a digital indication of their relative magnitudes.
Comparators are very useful mixed signal building
blocks because they provide analog functionality independent of program execution. The analog comparator
module includes the following features:
A single comparator is shown in Figure 17-2 along with
the relationship between the analog input levels and
the digital output. When the analog voltage at VIN+ is
less than the analog voltage at VIN-, the output of the
comparator is a digital low level. When the analog voltage at VIN+ is greater than the analog voltage at VIN-,
the output of the comparator is a digital high level.
•
•
•
•
•
•
•
•
•
The comparators available for this device are listed in
Table 17-1.
Independent comparator control
Programmable input selection
Comparator output is available internally/externally
Programmable output polarity
Interrupt-On-Change
Wake-up from Sleep
Programmable speed/power optimization
PWM shutdown
Programmable and Fixed Voltage Reference
FIGURE 17-1:
TABLE 17-1:
AVAILABLE COMPARATORS
Device
C1
PIC12(L)F1571
●
PIC12(L)F1572
●
COMPARATOR MODULE SIMPLIFIED BLOCK DIAGRAM
Rev. 10-000027C
9/6/2013
CxNCH<2:0>
3
CxON(1)
000
CxIN0CxIN1-
001
Reserved
010
Reserved
011
Reserved
100
Reserved
101
FVR_buffer2
110
CxON(1)
CxVN
00
DAC_out
01
FVR_buffer2
10
Note 1:
2
Interrupt
Falling
Edge
CxINTN
set bit
CxIF
-
D
CxOUT
Q
MCxOUT
+
Q1
CxSP CxHYS
CxPOL
CxOUT_async
to
peripherals
CxOUT_sync
to
peripherals
CxSYNC
CxOE
0
TRIS bit
CxOUT
D
11
CxPCH<1:0>
CxINTP
Cx
CxVP
111
CxIN+
Interrupt
Rising
Edge
CxON(1)
Q
1
(From Timer1 Module) T1CLK
When CxON = 0, all multiplexer inputs are disconnected and the Comparator will produce a ‘0’ at the output.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 147
PIC12(L)F1571/2
FIGURE 17-2:
SINGLE COMPARATOR
17.2.2
VIN+
+
VIN-
–
Configuring the CxPCH<1:0> bits of the CMxCON1
register directs an internal voltage reference or an
analog pin to the non-inverting input of the comparator:
Output
VINVIN+
17.2
CxIN+ analog pin
DAC1_output
FVR_buffer2
VSS
See Section 13.0 “Fixed Voltage Reference (FVR)”
for more information on the Fixed Voltage Reference
module.
See Section 16.0 “5-Bit Digital-to-Analog Converter
(DAC) Module” for more information on the DAC input
signal.
Output
Note:
•
•
•
•
The black areas of the output of the
comparator represents the uncertainty
due to input offsets and response time.
Comparator Control
The comparator has two control registers: CMxCON0
and CMxCON1.
Any time the comparator is disabled (CxON = 0), all
comparator inputs are disabled.
17.2.3
Enable
Output selection
Output polarity
Speed/power selection
Hysteresis enable
Output synchronization
The CMxCON1 register (see Register 17-2) contains
control bits for the following:
•
•
•
•
Interrupt enable
Interrupt edge polarity
Positive input channel selection
Negative input channel selection
17.2.1
COMPARATOR ENABLE
Setting the CxON bit of the CMxCON0 register enables
the comparator for operation. Clearing the CxON bit
disables the comparator resulting in minimum current
consumption.
COMPARATOR NEGATIVE INPUT
SELECTION
The CxNCH<2:0> bits of the CMxCON0 register direct
one of the input sources to the comparator inverting input.
Note:
The CMxCON0 register (see Register 17-1) contains
control and status bits for the following:
•
•
•
•
•
•
COMPARATOR POSITIVE INPUT
SELECTION
17.2.4
To use CxIN+ and CxIN- pins as analog
input, the appropriate bits must be set in
the ANSELx register and the corresponding TRISx bits must also be set to disable
the output drivers.
COMPARATOR OUTPUT SELECTION
The output of the comparator can be monitored by
reading either the CxOUT bit of the CMxCON0 register
or the MCxOUT bit of the CMOUT register. In order to
make the output available for an external connection,
the following conditions must be true:
• CxOE bit of the CMxCON0 register must be set
• Corresponding TRISx bit must be cleared
• CxON bit of the CMxCON0 register must be set
The synchronous comparator output signal
(CxOUT_sync) is available to the following peripheral(s):
• Analog-to-Digital Converter (ADC)
• Timer1
The asynchronous comparator output signal
(CxOUT_async) is available to the following peripheral(s):
• Complementary Waveform Generator (CWG)
Note 1: The CxOE bit of the CMxCON0 register
overrides the port data latch. Setting the
CxON bit of the CMxCON0 register has
no impact on the port override.
2: The internal output of the comparator is
latched with each instruction cycle.
Unless otherwise specified, external
outputs are not latched.
DS40001723D-page 148
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17.2.5
COMPARATOR OUTPUT POLARITY
Inverting the output of the comparator is functionally
equivalent to swapping the comparator inputs. The
polarity of the comparator output can be inverted by
setting the CxPOL bit of the CMxCON0 register.
Clearing the CxPOL bit results in a non-inverted output.
Table 17-2 shows the output state versus input
conditions, including polarity control.
TABLE 17-2:
COMPARATOR OUTPUT
STATE VS. INPUT CONDITIONS
Input Condition
CxVN > CxVP
CxVN < CxVP
CxVN > CxVP
CxVN < CxVP
17.2.6
CxPOL
CxOUT
0
0
1
1
0
1
1
0
17.3
A simplified circuit for an analog input is shown in
Figure 17-3. Since the analog input pins share their
connection with a digital input, they have reverse
biased ESD protection diodes to VDD and VSS. The
analog input, therefore, must be between VSS and VDD.
If the input voltage deviates from this range by more
than 0.6V in either direction, one of the diodes is
forward-biased and a latch-up may occur.
A maximum source impedance of 10 k is recommended
for the analog sources. Also, any external component
connected to an analog input pin, such as a capacitor or
a Zener diode, should have very little leakage current to
minimize inaccuracies introduced.
Note 1: When reading a PORT register, all pins
configured as analog inputs will read as a
‘0’. Pins configured as digital inputs will
convert as an analog input, according to
the input specification.
COMPARATOR SPEED/POWER
SELECTION
The trade-off between speed or power can be optimized during program execution with the CxSP control
bit. The default state for this bit is ‘1’, which selects the
Normal Speed mode. Device power consumption can
be optimized at the cost of slower comparator
propagation delay by clearing the CxSP bit to ‘0’.
FIGURE 17-3:
Analog Input Connection
Considerations
2: Analog levels on any pin defined as a
digital input, may cause the input buffer to
consume more current than is specified.
ANALOG INPUT MODEL
Rev. 10-000071A
8/2/2013
VDD
RS < 10K
Analog
Input pin
VT § 0.6V
RIC
To Comparator
ILEAKAGE(1)
CPIN
5pF
VA
VT § 0.6V
VSS
Legend: CPIN
ILEAKAGE
RIC
RS
VA
VT
Note 1:
= Input Capacitance
= Leakage Current at the pin due to various junctions
= Interconnect Resistance
= Source Impedance
= Analog Voltage
= Threshold Voltage
See Section 26.0 “Electrical Specifications”.
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17.4
Comparator Hysteresis
A selectable amount of separation voltage can be
added to the input pins of each comparator to provide a
hysteresis function to the overall operation. Hysteresis
is enabled by setting the CxHYS bit of the CMxCON0
register.
See Section 26.0 “Electrical Specifications” for
more information.
17.5
Timer1 Gate Operation
The output resulting from a comparator operation can
be used as a source for gate control of Timer1. See
Section 19.5 “Timer1 Gate” for more information.
This feature is useful for timing the duration or interval
of an analog event.
It is recommended that the comparator output be
synchronized to Timer1. This ensures that Timer1 does
not increment while a change in the comparator is
occurring.
17.5.1
COMPARATOR OUTPUT
SYNCHRONIZATION
17.6
An interrupt can be generated upon a change in the output value of the comparator for each comparator, a rising
edge detector and a falling edge detector are present.
When either edge detector is triggered and its associated enable bit is set (CxINTP and/or CxINTN bits of
the CMxCON1 register), the corresponding interrupt
flag bit (CxIF bit of the PIR2 register) will be set.
To enable the interrupt, you must set the following bits:
• CxON and CxPOL bits of the CMxCON0 register
• CxIE bit of the PIE2 register
• CxINTP bit of the CMxCON1 register (for a rising
edge detection)
• CxINTN bit of the CMxCON1 register (for a falling
edge detection)
• PEIE and GIE bits of the INTCON register
The associated interrupt flag bit, CxIF bit of the PIR2
register, must be cleared in software. If another edge is
detected while this flag is being cleared, the flag will still
be set at the end of the sequence.
Note:
The output from the Cx comparator can be
synchronized with Timer1 by setting the CxSYNC bit of
the CMxCON0 register.
Once enabled, the comparator output is latched on the
falling edge of the Timer1 source clock. If a prescaler is
used with Timer1, the comparator output is latched after
the prescaling function. To prevent a race condition, the
comparator output is latched on the falling edge of the
Timer1 clock source and Timer1 increments on the
rising edge of its clock source. See the Comparator
Block Diagram (Figure 17-2) and the Timer1 Block
Diagram (Figure 19-1) for more information.
DS40001723D-page 150
Comparator Interrupt
17.7
Although a comparator is disabled, an
interrupt can be generated by changing
the output polarity with the CxPOL bit of
the CMxCON0 register, or by switching
the comparator on or off with the CxON bit
of the CMxCON0 register.
Comparator Response Time
The comparator output is indeterminate for a period of
time after the change of an input source or the selection
of a new reference voltage. This period is referred to as
the response time. The response time of the comparator
differs from the settling time of the voltage reference.
Therefore, both of these times must be considered when
determining the total response time to a comparator
input change. See the Comparator and Voltage
Reference Specifications in Section 26.0 “Electrical
Specifications” for more details.
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17.8
Register Definitions: Comparator Control
REGISTER 17-1:
CMxCON0: COMPARATOR Cx CONTROL REGISTER 0
R/W-0/0
R-0/0
R/W-0/0
R/W-0/0
U-0
R/W-0/0
R/W-0/0
R/W-0/0
CxON
CxOUT
CxOE
CxPOL
—
CxSP
CxHYS
CxSYNC
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
CxON: Comparator Enable bit
1 = Comparator is enabled
0 = Comparator is disabled and consumes no active power
bit 6
CxOUT: Comparator Output bit
If CxPOL = 1 (inverted polarity):
1 = CxVP < CxVN
0 = CxVP > CxVN
If CxPOL = 0 (non-inverted polarity):
1 = CxVP > CxVN
0 = CxVP < CxVN
bit 5
CxOE: Comparator Output Enable bit
1 = CxOUT is present on the CxOUT pin; requires that the associated TRISx bit be cleared to actually
drive the pin, not affected by CxON
0 = CxOUT is internal only
bit 4
CxPOL: Comparator Output Polarity Select bit
1 = Comparator output is inverted
0 = Comparator output is not inverted
bit 3
Unimplemented: Read as ‘0’
bit 2
CxSP: Comparator Speed/Power Select bit
1 = Comparator mode is in Normal Power, Higher Speed mode
0 = Comparator mode is in Low-Power, Low-Speed mode
bit 1
CxHYS: Comparator Hysteresis Enable bit
1 = Comparator hysteresis is enabled
0 = Comparator hysteresis is disabled
bit 0
CxSYNC: Comparator Output Synchronous Mode bit
1 = Comparator output to Timer1 and I/O pin is synchronous to changes on Timer1 clock source;
output updated on the falling edge of Timer1 clock source
0 = Comparator output to Timer1 and I/O pin is asynchronous
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REGISTER 17-2:
CMxCON1: COMPARATOR Cx CONTROL REGISTER 1
R/W-0/0
R/W-0/0
CxINTP
CxINTN
R/W-0/0
R/W-0/0
CxPCH<1:0>
U-0
R/W-0/0
R/W-0/0
R/W-0/0
CxNCH<2:0>
—
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
CxINTP: Comparator Interrupt on Positive Going Edge Enable bit
1 = The CxIF interrupt flag will be set upon a positive going edge of the CxOUT bit
0 = No interrupt flag will be set on a positive going edge of the CxOUT bit
bit 6
CxINTN: Comparator Interrupt on Negative Going Edge Enable bit
1 = The CxIF interrupt flag will be set upon a negative going edge of the CxOUT bit
0 = No interrupt flag will be set on a negative going edge of the CxOUT bit
bit 5-4
CxPCH<1:0>: Comparator Positive Input Channel Select bits
11 = CxVP connects to VSS
10 = CxVP connects to FVR Voltage Reference
01 = CxVP connects to DAC Voltage Reference
00 = CxVP connects to CxIN+ pin
bit 3
Unimplemented: Read as ‘0’
bit 2-0
CxNCH<1:0>: Comparator Negative Input Channel Select bits
111 = CxVN connects to GND
110 = CxVN connects to FVR Voltage Reference
101 = Reserved
100 = Reserved
011 = Reserved
010 = Reserved
001 = CxVN connects to CxIN1- pin
000 = CxVN connects to CxIN0- pin
REGISTER 17-3:
U-0
CMOUT: COMPARATOR OUTPUT REGISTER
U-0
—
—
U-0
—
U-0
—
U-0
—
U-0
—
U-0
R-0/0
—
MC1OUT
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-1
Unimplemented: Read as ‘0’
bit 0
MC1OUT: Mirror Copy of C1OUT bit
DS40001723D-page 152
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TABLE 17-3:
Name
ANSELA
SUMMARY OF REGISTERS ASSOCIATED WITH COMPARATOR MODULE
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
—
—
—
ANSA4
—
C1OE
C1POL
—
Bit 2
C1ON
C1OUT
CM1CON1
C1NTP
C1INTN
—
—
—
—
DACEN
—
DACOE
—
DACPSS<1:0>
CDAFVR<1:0>
CMOUT
DAC1CON0
—
—
—
FVRCON
FVREN
FVRRDY
TSEN
TSRNG
INTCON
DAC1CON1
C1SP
—
—
Bit 0
ANSA<2:0>
CM1CON0
C1PCH<1:0>
Bit 1
114
C1HYS
C1SYNC
C1NCH<2:0>
—
Register
on Page
151
152
—
MC1OUT
152
—
—
145
DACR<4:0>
145
ADFVR<1:0>
125
GIE
PEIE
TMR0IE
INTE
IOCIE
TMR0IF
INTF
IOCIF
74
PIE2
—
—
C1IE
—
—
—
—
—
76
PIR2
—
—
C1IF
—
—
—
—
—
PORTA
—
—
RA5
RA4
RA3
LATA
—
—
LATA5
LATA4
TRISA
—
—
TRISA5
TRISA4
79
RA<2:0>
113
—
LATA<2:0>
114
—(1)
TRISA<2:0>
113
Legend: — = unimplemented location, read as ‘0’. Shaded cells are unused by the comparator module.
Note 1: Unimplemented, read as ‘1’.
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DS40001723D-page 154
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18.0
TIMER0 MODULE
18.1.2
8-BIT COUNTER MODE
The Timer0 module is an 8-bit timer/counter with the
following features:
In 8-Bit Counter mode, the Timer0 module will increment
on every rising or falling edge of the T0CKI pin.
•
•
•
•
•
•
In 8-Bit Counter mode, the T0CKI pin is selected by
setting the TMR0CS bit in the OPTION_REG register
to ‘1’.
8-Bit Timer/Counter register (TMR0)
3-bit prescaler (independent of Watchdog Timer)
Programmable internal or external clock source
Programmable external clock edge selection
Interrupt on overflow
TMR0 can be used to gate Timer1
The rising or falling transition of the incrementing edge
for either input source is determined by the TMR0SE bit
in the OPTION_REG register.
Figure 18-1 is a block diagram of the Timer0 module.
18.1
Timer0 Operation
The Timer0 module can be used as either an 8-bit timer
or an 8-bit counter.
18.1.1
8-BIT TIMER MODE
The Timer0 module will increment every instruction
cycle if used without a prescaler. The 8-Bit Timer mode
is selected by clearing the TMR0CS bit of the
OPTION_REG register.
When TMR0 is written, the increment is inhibited for
two instruction cycles immediately following the write.
Note:
The value written to the TMR0 register
can be adjusted in order to account for the
two instruction cycle delay when TMR0 is
written.
FIGURE 18-1:
TIMER0 BLOCK DIAGRAM
Rev. 10-000017A
8/5/2013
TMR0CS
Fosc/4
T0CKI(1)
PSA
0
1
TMR0SE
1
write
to
TMR0
Prescaler
R
0 FOSC/2
T0CKI
Sync Circuit
PS<2:0>
T0_overflow
TMR0
Q1
set bit
TMR0IF
Note 1: The T0CKI prescale output frequency should not exceed FOSC/8.
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18.1.3
SOFTWARE PROGRAMMABLE
PRESCALER
A software programmable prescaler is available for
exclusive use with Timer0. The prescaler is enabled by
clearing the PSA bit of the OPTION_REG register.
Note:
The Watchdog Timer (WDT) uses its own
independent prescaler.
There are eight prescaler options for the Timer0 module,
ranging from 1:2 to 1:256. The prescale values are
selectable via the PS<2:0> bits of the OPTION_REG
register. In order to have a 1:1 prescaler value for the
Timer0 module, the prescaler must be disabled by
setting the PSA bit of the OPTION_REG register.
The prescaler is not readable or writable. All instructions
writing to the TMR0 register will clear the prescaler.
18.1.4
18.1.5
8-BIT COUNTER MODE
SYNCHRONIZATION
When in 8-Bit Counter mode, the incrementing edge on
the T0CKI pin must be synchronized to the instruction
clock. Synchronization can be accomplished by
sampling the prescaler output on the Q2 and Q4 cycles
of the instruction clock. The high and low periods of the
external clocking source must meet the timing
requirements as shown in Section 26.0 “Electrical
Specifications”.
18.1.6
OPERATION DURING SLEEP
Timer0 cannot operate while the processor is in Sleep
mode. The contents of the TMR0 register will remain
unchanged while the processor is in Sleep mode.
TIMER0 INTERRUPT
Timer0 will generate an interrupt when the TMR0 register
overflows from FFh to 00h. The TMR0IF interrupt flag bit
of the INTCON register is set every time the TMR0
register overflows, regardless of whether or not the
Timer0 interrupt is enabled. The TMR0IF bit can only be
cleared in software. The Timer0 interrupt enable is the
TMR0IE bit of the INTCON register.
Note:
The Timer0 interrupt cannot wake the
processor from Sleep since the timer is
frozen during Sleep.
DS40001723D-page 156
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18.2
Register Definitions: Option Register
REGISTER 18-1:
OPTION_REG: OPTION REGISTER
R/W-1/1
R/W-1/1
R/W-1/1
R/W-1/1
R/W-1/1
WPUEN
INTEDG
TMR0CS
TMR0SE
PSA
R/W-1/1
R/W-1/1
R/W-1/1
PS<2:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
WPUEN: Weak Pull-Up Enable bit
1 = All weak pull-ups are disabled (except MCLR if it is enabled)
0 = Weak pull-ups are enabled by individual WPUx latch values
bit 6
INTEDG: Interrupt Edge Select bit
1 = Interrupt on rising edge of INT pin
0 = Interrupt on falling edge of INT pin
bit 5
TMR0CS: Timer0 Clock Source Select bit
1 = Transition on T0CKI pin
0 = Internal instruction cycle clock (FOSC/4)
bit 4
TMR0SE: Timer0 Source Edge Select bit
1 = Increment on high-to-low transition on T0CKI pin
0 = Increment on low-to-high transition on T0CKI pin
bit 3
PSA: Prescaler Assignment bit
1 = Prescaler is not assigned to the Timer0 module
0 = Prescaler is assigned to the Timer0 module
bit 2-0
PS<2:0>: Prescaler Rate Select bits
TABLE 18-1:
Name
Bit 7
TRISA
000
001
010
011
100
101
110
111
1:2
1:4
1:8
1 : 16
1 : 32
1 : 64
1 : 128
1 : 256
Bit 6
Bit 5
Bit 4
TRIGSEL<3:0>
GIE
OPTION_REG WPUEN
TMR0
Timer0 Rate
SUMMARY OF REGISTERS ASSOCIATED WITH TIMER0
ADCON2
INTCON
Bit Value
PEIE
TMR0IE
INTE
INTEDG TMR0CS TMR0SE
Bit 3
Bit 2
Bit 1
Bit 0
Register
on Page
—
—
—
—
137
IOCIE
TMR0IF
INTF
IOCIF
74
PSA
PS<2:0>
157
Holding Register for the 8-bit Timer0 Count
—
—
TRISA5
TRISA4
155*
—(1)
TRISA2
TRISA1
TRISA0
113
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used by the Timer0 module.
* Page provides register information.
Note 1: Unimplemented, read as ‘1’.
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DS40001723D-page 158
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19.0
TIMER1 MODULE WITH GATE
CONTROL
• Wake-up on overflow (external clock,
Asynchronous mode only)
• ADC auto-conversion trigger(s)
• Selectable gate source polarity
• Gate Toggle mode
• Gate Single-Pulse mode
• Gate value status
• Gate event interrupt
The Timer1 module is a 16-bit timer/counter with the
following features:
•
•
•
•
•
•
16-bit Timer/Counter register pair (TMR1H:TMR1L)
Programmable internal or external clock source
2-bit prescaler
Optionally synchronized comparator out
Multiple Timer1 gate (count enable) sources
Interrupt on overflow
FIGURE 19-1:
Figure 19-1 is a block diagram of the Timer1 module.
TIMER1 BLOCK DIAGRAM
T1GSS<1:0>
Rev. 10-000018D
8/5/2013
T1G
00
T0_overflow
01
C1OUT_sync
10
Reserved
11
T1GSPM
0
1
D
1
Single Pulse
Acq. Control
D
0
T1GVAL
Q
Q1
Q
T1GGO/DONE
T1GPOL
CK
Q
Interrupt
TMR1ON
R
set bit
TMR1GIF
det
T1GTM
TMR1GE
set flag bit
TMR1IF
TMR1ON
EN
T1_overflow
TMR1(2)
TMR1H
TMR1L
Q
Synchronized Clock Input
0
D
1
T1CLK
T1SYNC
TMR1CS<1:0>
LFINTOSC
(1)
11
10
T1CKI
Fosc
Internal Clock
01
00
Fosc/4
Internal Clock
Prescaler
1,2,4,8
Synchronize(3)
det
2
T1CKPS<1:0>
Fosc/2
Internal
Clock
Sleep
Input
Note 1: ST Buffer is high speed type when using T1CKI.
2: Timer1 register increments on rising edge.
3: Synchronize does not operate while in Sleep.
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19.1
Timer1 Operation
19.2
The Timer1 module is a 16-bit incrementing counter
which is accessed through the TMR1H:TMR1L register
pair. Writes to TMR1H or TMR1L directly update the
counter.
When used with an internal clock source, the module is
a timer and increments on every instruction cycle.
When used with an external clock source, the module
can be used as either a timer or counter and
increments on every selected edge of the external
source.
Timer1 is enabled by configuring the TMR1ON and
TMR1GE bits in the T1CON and T1GCON registers,
respectively. Table 19-1 displays the Timer1 enable
selections.
TABLE 19-1:
TIMER1 ENABLE
SELECTIONS
Clock Source Selection
The TMR1CS<1:0> bits of the T1CON register are used
to select the clock source for Timer1. Table 19-2
displays the clock source selections.
19.2.1
INTERNAL CLOCK SOURCE
When the internal clock source is selected, the
TMR1H:TMR1L register pair will increment on multiples
of FOSC, as determined by the Timer1 prescaler.
When the FOSC internal clock source is selected, the
Timer1 register value will increment by four counts every
instruction clock cycle. Due to this condition, a 2 LSB
error in resolution will occur when reading the Timer1
value. To utilize the full resolution of Timer1, an
asynchronous input signal must be used to gate the
Timer1 clock input.
The following asynchronous sources may be used:
Timer1
Operation
TMR1ON
TMR1GE
0
0
Off
0
1
Off
1
0
Always On
1
1
Count Enabled
• Asynchronous event on the T1G pin to Timer1 gate
• C1 or C2 comparator input to Timer1 gate
19.2.2
EXTERNAL CLOCK SOURCE
When the external clock source is selected, the Timer1
module may work as a timer or a counter.
When enabled to count, Timer1 is incremented on the rising edge of the external clock input T1CKI. The external
clock source can be synchronized to the microcontroller
system clock or it can run asynchronously.
Note:
In Counter mode, a falling edge must be
registered by the counter prior to the first
incrementing rising edge after any one or
more of the following conditions:
•
•
•
•
TABLE 19-2:
CLOCK SOURCE SELECTIONS
TMR1CS<1:0>
T1OSCEN(1)
11
x
LFINTOSC
10
x
External Clocking on T1CKI Pin
01
x
System Clock (FOSC)
x
Instruction Clock (FOSC/4)
00
Note 1:
Timer1 enabled after POR
Write to TMR1H or TMR1L
Timer1 is disabled
Timer1 is disabled (TMR1ON = 0)
when T1CKI is high, then Timer1 is
enabled (TMR1ON = 1) when T1CKI
is low
Clock Source
T1OSCEN is not available for these devices.
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19.3
Timer1 Prescaler
Timer1 has four prescaler options, allowing 1, 2, 4 or 8
divisions of the clock input. The T1CKPSx bits of the
T1CON register control the prescale counter. The
prescale counter is not directly readable or writable;
however, the prescaler counter is cleared upon a write to
TMR1H or TMR1L.
19.4
Timer1 Operation in
Asynchronous Counter Mode
If control bit, T1SYNC, of the T1CON register is set,
the external clock input is not synchronized. The timer
increments asynchronously to the internal phase
clocks. If the external clock source is selected then the
timer will continue to run during Sleep and can
generate an interrupt on overflow, which will wake-up
the processor. However, special precautions in
software are needed to read/write the timer (see
Section 19.4.1 “Reading and Writing Timer1 in
Asynchronous Counter Mode”).
Note:
19.4.1
When switching from synchronous to
asynchronous operation, it is possible to
skip an increment. When switching from
asynchronous to synchronous operation,
it is possible to produce an additional
increment.
READING AND WRITING TIMER1 IN
ASYNCHRONOUS COUNTER
MODE
Reading TMR1H or TMR1L while the timer is running
from an external asynchronous clock will ensure a valid
read (taken care of in hardware). However, the user
should keep in mind that reading the 16-bit timer in two
8-bit values itself, poses certain problems, since the
timer may overflow between the reads.
For writes, it is recommended that the user simply stop
the timer and write the desired values. A write
contention may occur by writing to the timer registers,
while the register is incrementing. This may produce an
unpredictable value in the TMR1H:TMR1L register pair.
19.5
Timer1 Gate
Timer1 can be configured to count freely or the count
can be enabled and disabled using Timer1 gate
circuitry. This is also referred to as Timer1 Gate Enable.
Timer1 gate can also be driven by multiple selectable
sources.
19.5.1
The Timer1 Gate Enable mode is enabled by setting
the TMR1GE bit of the T1GCON register. The polarity
of the Timer1 Gate Enable mode is configured using
the T1GPOL bit of the T1GCON register.
When Timer1 Gate Enable mode is enabled, Timer1
will increment on the rising edge of the Timer1 clock
source. When Timer1 Gate Enable mode is disabled,
no incrementing will occur and Timer1 will hold the
current count. See Figure 19-3 for timing details.
TABLE 19-3:
TIMER1 GATE ENABLE
SELECTIONS
T1CLK
T1GPOL
T1G

0
0
Counts

0
1
Holds Count

1
0
Holds Count

1
1
Counts
19.5.2
Timer1 Operation
TIMER1 GATE SOURCE
SELECTION
Timer1 gate source selections are shown in Table 19-4.
Source selection is controlled by the T1GSS<1:0> bits
of the T1GCON register. The polarity for each available
source is also selectable. Polarity selection is controlled
by the T1GPOL bit of the T1GCON register.
TABLE 19-4:
T1GSS<1:0>
TIMER1 GATE SOURCES
Timer1 Gate Source
00
Timer1 Gate Pin (T1G)
01
Overflow of Timer0 (T0_overflow)
(TMR0 increments from FFh to 00h)
10
Comparator 1 Output (C1OUT_sync)(1)
11
Reserved
Note 1:
 2013-2015 Microchip Technology Inc.
TIMER1 GATE ENABLE
Optionally synchronized comparator output.
DS40001723D-page 161
PIC12(L)F1571/2
19.5.2.1
T1G Pin Gate Operation
The T1G pin is one source for Timer1 gate control. It
can be used to supply an external source to the Timer1
gate circuitry.
19.5.2.2
Timer0 Overflow Gate Operation
When Timer0 increments from FFh to 00h, a low-tohigh pulse will automatically be generated and
internally supplied to the Timer1 gate circuitry.
19.5.3
TIMER1 GATE TOGGLE MODE
When Timer1 Gate Toggle mode is enabled, it is
possible to measure the full cycle length of a Timer1 gate
signal, as opposed to the duration of a single level pulse.
The Timer1 gate source is routed through a flip-flop that
changes state on every incrementing edge of the
signal. See Figure 19-4 for timing details.
Timer1 Gate Toggle mode is enabled by setting the
T1GTM bit of the T1GCON register. When the T1GTM
bit is cleared, the flip-flop is cleared and held clear. This
is necessary in order to control which edge is measured.
Note:
19.5.4
Enabling Toggle mode at the same time
as changing the gate polarity may result in
indeterminate operation.
If the Single-Pulse Gate mode is disabled by clearing the
T1GSPM bit in the T1GCON register, the T1GGO/DONE
bit should also be cleared.
Enabling the Toggle mode and the Single-Pulse mode
simultaneously will permit both sections to work
together. This allows the cycle times on the Timer1 gate
source to be measured. See Figure 19-6 for timing
details.
19.5.5
TIMER1 GATE VALUE STATUS
When Timer1 gate value status is utilized, it is possible
to read the most current level of the gate control value.
The value is stored in the T1GVAL bit in the T1GCON
register. The T1GVAL bit is valid even when the Timer1
gate is not enabled (TMR1GE bit is cleared).
19.5.6
TIMER1 GATE EVENT INTERRUPT
When Timer1 gate event interrupt is enabled, it is possible to generate an interrupt upon the completion of a
gate event. When the falling edge of T1GVAL occurs,
the TMR1GIF flag bit in the PIR1 register will be set. If
the TMR1GIE bit in the PIE1 register is set, then an
interrupt will be recognized.
The TMR1GIF flag bit operates even when the Timer1
gate is not enabled (TMR1GE bit is cleared).
TIMER1 GATE SINGLE-PULSE MODE
When Timer1 Gate Single-Pulse mode is enabled, it is
possible to capture a single-pulse gate event. Timer1
Gate Single-Pulse mode is first enabled by setting the
T1GSPM bit in the T1GCON register. Next, the T1GGO/
DONE bit in the T1GCON register must be set. The
Timer1 will be fully enabled on the next incrementing
edge. On the next trailing edge of the pulse, the T1GGO/
DONE bit will automatically be cleared. No other gate
events will be allowed to increment Timer1 until the
T1GGO/DONE bit is once again set in software. See
Figure 19-5 for timing details.
DS40001723D-page 162
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
19.6
Timer1 Interrupt
The Timer1 register pair (TMR1H:TMR1L) increments
to FFFFh and rolls over to 0000h. When Timer1 rolls
over, the Timer1 interrupt flag bit of the PIR1 register is
set. To enable the interrupt on rollover, you must set
these bits:
•
•
•
•
TMR1ON bit of the T1CON register
TMR1IE bit of the PIE1 register
PEIE bit of the INTCON register
GIE bit of the INTCON register
The interrupt is cleared by clearing the TMR1IF bit in
the Interrupt Service Routine.
Note:
19.7
The TMR1H:TMR1L register pair and the
TMR1IF bit should be cleared before
enabling interrupts.
The device will wake-up on an overflow and execute
the next instructions. If the GIE bit of the INTCON
register is set, the device will call the Interrupt Service
Routine.
Timer1 oscillator will continue to operate in Sleep
regardless of the T1SYNC bit setting.
19.7.1
ALTERNATE PIN LOCATIONS
This module incorporates I/O pins that can be moved to
other locations with the use of the Alternate Pin Function register, APFCON. To determine which pins can be
moved and what their default locations are upon a
Reset, see Section 11.1 “Alternate Pin Function” for
more information.
Timer1 Operation During Sleep
Timer1 can only operate during Sleep when set up in
Asynchronous Counter mode. In this mode, an external
crystal or clock source can be used to increment the
counter. To set up the timer to wake the device:
•
•
•
•
•
TMR1ON bit of the T1CON register must be set
TMR1IE bit of the PIE1 register must be set
PEIE bit of the INTCON register must be set
T1SYNC bit of the T1CON register must be set
TMR1CS bits of the T1CON register must be
configured
FIGURE 19-2:
TIMER1 INCREMENTING EDGE
T1CKI = 1
when TMR1
is Enabled
T1CKI = 0
when TMR1
is Enabled
Note 1:
2:
Arrows indicate counter increments.
In Counter mode, a falling edge must be registered by the counter prior to the first incrementing rising
edge of the clock.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 163
PIC12(L)F1571/2
FIGURE 19-3:
TIMER1 GATE ENABLE MODE
TMR1GE
T1GPOL
t1g_in
T1CKI
T1GVAL
N
Timer1
FIGURE 19-4:
N+1
N+2
N+3
N+4
TIMER1 GATE TOGGLE MODE
TMR1GE
T1GPOL
T1GTM
t1g_in
T1CKI
T1GVAL
Timer1
DS40001723D-page 164
N
N+1 N+2 N+3
N+4
N+5 N+6 N+7
N+8
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
FIGURE 19-5:
TIMER1 GATE SINGLE-PULSE MODE
TMR1GE
T1GPOL
T1GSPM
T1GGO/
DONE
Cleared by Hardware on
Falling Edge of T1GVAL
Set by Software
Counting Enabled on
Rising Edge of T1G
t1g_in
T1CKI
T1GVAL
Timer1
TMR1GIF
N
Cleared by Software
 2013-2015 Microchip Technology Inc.
N+1
N+2
Set by Hardware on
Falling Edge of T1GVAL
Cleared by
Software
DS40001723D-page 165
PIC12(L)F1571/2
FIGURE 19-6:
TIMER1 GATE SINGLE-PULSE AND TOGGLE COMBINED MODE
TMR1GE
T1GPOL
T1GSPM
T1GTM
T1GGO/
DONE
Cleared by Hardware on
Falling Edge of T1GVAL
Set by Software
Counting Enabled on
Rising Edge of T1G
t1g_in
T1CKI
T1GVAL
Timer1
TMR1GIF
DS40001723D-page 166
N
Cleared by Software
N+1
N+2
N+3
N+4
Set by Hardware on
Falling Edge of T1GVAL
Cleared by
Software
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
19.8
Register Definitions: Timer1 Control
REGISTER 19-1:
R/W-0/u
T1CON: TIMER1 CONTROL REGISTER
R/W-0/u
R/W-0/u
TMR1CS<1:0>
R/W-0/u
T1CKPS<1:0>
U-0
R/W-0/u
U-0
R/W-0/u
—
T1SYNC
—
TMR1ON
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-6
TMR1CS<1:0>: Timer1 Clock Source Select bits
11 = Timer1 clock source is the LFINTOSC
10 = Timer1 clock source is the T1CKI pin (on the rising edge)
01 = Timer1 clock source is the system clock (FOSC)
00 = Timer1 clock source is the instruction clock (FOSC/4)
bit 5-4
T1CKPS<1:0>: Timer1 Input Clock Prescale Select bits
11 = 1:8 Prescale value
10 = 1:4 Prescale value
01 = 1:2 Prescale value
00 = 1:1 Prescale value
bit 3
Unimplemented: Read as ‘0’
bit 2
T1SYNC: Timer1 Synchronization Control bit
1 = Does not synchronize the asynchronous clock input
0 = Synchronizes the asynchronous clock input with the system clock (FOSC)
bit 1
Unimplemented: Read as ‘0’
bit 0
TMR1ON: Timer1 On bit
1 = Enables Timer1
0 = Stops Timer1 and clears Timer1 gate flip-flop
 2013-2015 Microchip Technology Inc.
DS40001723D-page 167
PIC12(L)F1571/2
REGISTER 19-2:
T1GCON: TIMER1 GATE CONTROL REGISTER
R/W-0/u
R/W-0/u
R/W-0/u
R/W-0/u
R/W/HC-0/u
R-x/x
TMR1GE
T1GPOL
T1GTM
T1GSPM
T1GGO/
DONE
T1GVAL
R/W-0/u
bit 7
R/W-0/u
T1GSS<1:0>
bit 0
Legend:
R = Readable bit
W = Writable bit
HC = Hardware Clearable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
TMR1GE: Timer1 Gate Enable bit
If TMR1ON = 0:
This bit is ignored.
If TMR1ON = 1:
1 = Timer1 counting is controlled by the Timer1 gate function
0 = Timer1 counts regardless of Timer1 gate function
bit 6
T1GPOL: Timer1 Gate Polarity bit
1 = Timer1 gate is active-high (Timer1 counts when gate is high)
0 = Timer1 gate is active-low (Timer1 counts when gate is low)
bit 5
T1GTM: Timer1 Gate Toggle Mode bit
1 = Timer1 Gate Toggle mode is enabled
0 = Timer1 Gate Toggle mode is disabled and toggle flip-flop is cleared
Timer1 gate flip-flop toggles on every rising edge.
bit 4
T1GSPM: Timer1 Gate Single-Pulse Mode bit
1 = Timer1 Gate Single-Pulse mode is enabled and is controlling Timer1 gate
0 = Timer1 Gate Single-Pulse mode is disabled
bit 3
T1GGO/DONE: Timer1 Gate Single-Pulse Acquisition Status bit
1 = Timer1 gate single-pulse acquisition is ready, waiting for an edge
0 = Timer1 gate single-pulse acquisition has completed or has not been started
bit 2
T1GVAL: Timer1 Gate Value Status bit
Indicates the current state of the Timer1 gate that could be provided to TMR1H:TMR1L. Unaffected
by Timer1 Gate Enable bit (TMR1GE).
bit 1-0
T1GSS<1:0>: Timer1 Gate Source Select bits
11 = Reserved
10 = Comparator 1 optionally synchronized output (C1OUT_sync)
01 = Timer0 overflow output (T0_overflow)
00 = Timer1 gate pin (T1G)
DS40001723D-page 168
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
TABLE 19-5:
Name
ANSELA
APFCON
INTCON
OSCSTAT
SUMMARY OF REGISTERS ASSOCIATED WITH TIMER1
Bit 7
Bit 6
Bit 5
Bit 4
—
—
—
ANSA4
—
—
T1GSEL
RXDTSEL CWGASEL CWGBSEL
Bit 3
Bit 2
Bit 1
Bit 0
ANSA<2:0>
TXCKSEL
P2SEL
Register
on Page
114
P1SEL
110
GIE
PEIE
TMR0IE
INTE
IOCIE
TMR0IF
INTF
IOCIF
74
—
PLLR
OSTS
HFIOFR
HFIOFL
MFIOFR
LFIOFR
HFIOFS
56
(2)
(2)
PIE1
TMR1GIE
ADIE
RCIE
TXIE
—
—
TMR2IE
TMR1IE
75
PIR1
TMR1GIF
ADIF
RCIF(2)
TXIF(2)
—
—
TMR2IF
TMR1IF
79
TMR1H
Holding Register for the Most Significant Byte of the 16-bit TMR1 Count
163*
TMR1L
Holding Register for the Least Significant Byte of the 16-bit TMR1 Count
163*
TRISA
—
T1CON
TMR1CS<1:0>
T1GCON
Legend:
*
Note 1:
2:
TMR1GE
—
T1GPOL
TRISA<5:4>
T1CKPS<1:0>
T1GTM
T1GSPM
(1)
—
TRISA<2:0>
113
—
T1SYNC
—
TMR1ON
T1GGO/
DONE
T1GVAL
T1GSS<1:0>
167
168
— = unimplemented location, read as ‘0’. Shaded cells are not used by the Timer1 module.
Page provides register information.
Unimplemented, read as ‘1’.
PIC12(L)F1572 only.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 169
PIC12(L)F1571/2
NOTES:
DS40001723D-page 170
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
20.0
TIMER2 MODULE
The Timer2 module incorporates the following features:
• 8-Bit Timer and Period registers (TMR2 and PR2,
respectively)
• Readable and writable (both registers)
• Software programmable prescaler (1:1, 1:4, 1:16
and 1:64)
• Software programmable postscaler (1:1 to 1:16)
• Interrupt on TMR2 match with PR2
See Figure 20-1 for a block diagram of Timer2.
FIGURE 20-1:
TIMER2 BLOCK DIAGRAM
Rev. 10-000019A
7/30/2013
T2_match
Prescaler
1:1, 1:4, 1:16, 1:64
Fosc/4
R
TMR2
To Peripherals
2
T2CKPS<1:0>
Postscaler
1:1 to 1:16
Comparator
set bit
TMR2IF
4
T2OUTPS<3:0>
PR2
FIGURE 20-2:
TIMER2 TIMING DIAGRAM
Rev. 10-000020A
7/30/2013
FOSC/4
1:4
Prescale
0x03
PR2
TMR2
0x00
0x01
0x02
0x03
0x00
0x01
0x02
Pulse Width(1)
T2_match
Note 1: The Pulse Width of T2_match is equal to the scaled input of TMR2.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 171
PIC12(L)F1571/2
20.1
Timer2 Operation
The clock input to the Timer2 module is the system
instruction clock (FOSC/4).
TMR2 increments from 00h on each clock edge.
A 4-bit counter/prescaler on the clock input allows direct
input, divide-by-4 and divide-by-16 prescale options.
These options are selected by the prescaler control bits,
T2CKPS<1:0> of the T2CON register. The value of
TMR2 is compared to that of the Period register, PR2, on
each clock cycle. When the two values match, the
comparator generates a match signal as the timer
output. This signal also resets the value of TMR2 to 00h
on the next cycle and drives the output counter/
postscaler (see Section 20.2 “Timer2 Interrupt”).
The TMR2 and PR2 registers are both directly readable
and writable. The TMR2 register is cleared on any
device Reset, whereas the PR2 register initializes to
FFh. Both the prescaler and postscaler counters are
cleared on the following events:
•
•
•
•
•
•
•
•
•
A write to the TMR2 register
A write to the T2CON register
Power-on Reset (POR)
Brown-out Reset (BOR)
MCLR Reset
Watchdog Timer (WDT) Reset
Stack Overflow Reset
Stack Underflow Reset
RESET Instruction
Note:
20.2
20.3
The output of TMR2 is T2_match.
The T2_match signal is synchronous with the system
clock. Figure 20-3 shows two examples of the timing of
the T2_match signal relative to FOSC and prescale
value, T2CKPS<1:0>. The upper diagram illustrates 1:1
prescale timing and the lower diagram, 1:X prescale
timing.
FIGURE 20-3:
Timer2 can also generate an optional device interrupt.
The Timer2 output signal (T2_match) provides the input
for the 4-bit counter/postscaler. This counter generates
the TMR2 match interrupt flag which is latched in
TMR2IF of the PIR1 register. The interrupt is enabled by
setting the TMR2 Match Interrupt Enable bit, TMR2IE of
the PIE1 register.
T2_MATCH TIMING
DIAGRAM
Rev. 10-000021A
7/30/2013
Q1
Q2
Q3
Q4
Q1
FOSC
TCY1
FOSC/4
T2_match
TMR2 = 0
TMR2 = PR2
match
PRESCALE = 1:1
(T2CKPS<1:0> = 00)
TCY1
TCY2 ...
...
T2_match
TCYX
...
FOSC/4
TMR2 is not cleared when T2CON is
written.
Timer2 Interrupt
Timer2 Output
TMR2 = PR2
match
TMR2 = 0
PRESCALE = 1:X
(T2CKPS<1:0> = 01,10,11)
20.4
Timer2 Operation During Sleep
Timer2 cannot be operated while the processor is in
Sleep mode. The contents of the TMR2 and PR2
registers will remain unchanged while the processor is
in Sleep mode.
A range of 16 postscale options (from 1:1 through 1:16
inclusive) can be selected with the postscaler control
bits, T2OUTPS<3:0>, of the T2CON register.
DS40001723D-page 172
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
20.5
Register Definitions: Timer2 Control
REGISTER 20-1:
U-0
T2CON: TIMER2 CONTROL REGISTER
R/W-0/0
R/W-0/0
—
R/W-0/0
R/W-0/0
T2OUTPS<3:0>
R/W-0/0
R/W-0/0
TMR2ON
R/W-0/0
T2CKPS<1:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
Unimplemented: Read as ‘0’
bit 6-3
T2OUTPS<3:0>: Timer2 Output Postscaler Select bits
0000 = 1:1 Postscaler
0001 = 1:2 Postscaler
0010 = 1:3 Postscaler
0011 = 1:4 Postscaler
0100 = 1:5 Postscaler
0101 = 1:6 Postscaler
0110 = 1:7 Postscaler
0111 = 1:8 Postscaler
1000 = 1:9 Postscaler
1001 = 1:10 Postscaler
1010 = 1:11 Postscaler
1011 = 1:12 Postscaler
1100 = 1:13 Postscaler
1101 = 1:14 Postscaler
1110 = 1:15 Postscaler
1111 = 1:16 Postscaler
bit 2
TMR2ON: Timer2 On bit
1 = Timer2 is on
0 = Timer2 is off
bit 1-0
T2CKPS<1:0>: Timer2 Clock Prescale Select bits
00 = Prescaler is 1
01 = Prescaler is 4
10 = Prescaler is 16
11 = Prescaler is 64
TABLE 20-1:
SUMMARY OF REGISTERS ASSOCIATED WITH TIMER2
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Register
on Page
INTCON
GIE
PEIE
TMR0IE
INTE
IOCIE
TMR0IF
INTF
IOCIF
74
TXIE(1)
—
—
TMR2IE
TMR1IE
75
TXIF(1)
—
—
TMR2IF
TMR1IF
78
PIE1
TMR1GIE
ADIE
RCIE(1)
PIR1
TMR1GIF
ADIF
RCIF(1)
PR2
Timer2 Module Period Register
T2CON
TMR2
—
T2OUTPS<3:0>
171*
TMR2ON
T2CKPS<1:0>
Holding Register for the 8-bit TMR2 Count
173
171*
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used for Timer2 module.
* Page provides register information.
Note 1: PIC12(L)F1572 only.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 173
PIC12(L)F1571/2
NOTES:
DS40001723D-page 174
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
21.0
ENHANCED UNIVERSAL
SYNCHRONOUS
ASYNCHRONOUS RECEIVER
TRANSMITTER (EUSART)
The EUSART module includes the following capabilities:
•
•
•
•
•
•
•
•
•
•
Full-duplex asynchronous transmit and receive
Two-character input buffer
One-character output buffer
Programmable 8-bit or 9-bit character length
Address detection in 9-bit mode
Input buffer overrun error detection
Received character framing error detection
Half-duplex synchronous master
Half-duplex synchronous slave
Programmable clock polarity in synchronous
modes
• Sleep operation
The Enhanced Universal Synchronous Asynchronous
Receiver Transmitter (EUSART) module is a serial I/O
communications peripheral. It contains all the clock
generators, shift registers and data buffers necessary
to perform an input or output serial data transfer, independent of device program execution. The EUSART,
also known as a Serial Communications Interface
(SCI), can be configured as a full-duplex asynchronous
system or half-duplex synchronous system.
Full-Duplex mode is useful for communications with
peripheral systems, such as CRT terminals and personal computers. Half-Duplex Synchronous mode is
intended for communications with peripheral devices,
such as A/D or D/A integrated circuits, serial EEPROMs
or other microcontrollers. These devices typically do not
have internal clocks for baud rate generation and require
the external clock signal provided by a master
synchronous device.
FIGURE 21-1:
The EUSART module implements the following
additional features, making it ideally suited for use in
Local Interconnect Network (LIN) bus systems:
• Automatic detection and calibration of the baud rate
• Wake-up on Break reception
• 13-bit Break character transmit
Block diagrams of the EUSART transmitter and
receiver are shown in Figure 21-1 and Figure 21-2.
EUSART TRANSMIT BLOCK DIAGRAM
Rev. 10-000113B
7/14/2015
Data bus
TXIE
8
Interrupt
TXREG register
TXIF
8
MSb
LSb
(8)
0
TX/CK
Pin Buffer
and Control
Transmit Shift Register (TSR)
TXEN
Baud Rate Generator
TRMT
FOSC
÷n
TX9
n
BRG16
TX9D
+1
Multiplier
x4
x16
x64
SYNC
1 x 0 0
0
BRGH
x 1 1 0
0
BRG16
x 1 0 1
0
SPBRGH SPBRGL
 2013-2015 Microchip Technology Inc.
DS40001723D-page 175
PIC12(L)F1571/2
FIGURE 21-2:
EUSART RECEIVE BLOCK DIAGRAM
Rev. 10-000114A
7/30/2013
CREN
OERR
RCIDL
SPEN
RSR Register
MSb
RX/DT pin
Pin Buffer
and Control
Baud Rate Generator
Data
Recovery
FOSC
Stop (8)
7
LSb
1
0
Start
÷n
RX9
BRG16
+1
Multiplier
x4
x16
x64
SYNC
1 x 0 0
0
BRGH
x 1 1 0
0
BRG16
x 1 0 1
0
SPBRGH SPBRGL
n
FIFO
FERR
RX9D
RCREG Register
8
Data Bus
RCIF
RCIE
Interrupt
The operation of the EUSART module is controlled
through three registers:
These registers are detailed in Register 21-1,
Register 21-2 and Register 21-3, respectively.
• Transmit Status and Control (TXSTA)
• Receive Status and Control (RCSTA)
• Baud Rate Control (BAUDCON)
When the receiver or transmitter section is not enabled,
then the corresponding RX or TX pin may be used for
general purpose input and output.
DS40001723D-page 176
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
21.1
EUSART Asynchronous Mode
The EUSART transmits and receives data using the
standard Non-Return-to-Zero (NRZ) format. NRZ is
implemented with two levels: a VOH mark state which
represents a ‘1’ data bit, and a VOL space state which
represents a ‘0’ data bit. NRZ refers to the fact that consecutively transmitted data bits of the same value stay
at the output level of that bit without returning to a neutral
level between each bit transmission. An NRZ transmission port Idles in the mark state. Each character
transmission consists of one Start bit, followed by eight
or nine data bits and is always terminated by one or
more Stop bits. The Start bit is always a space and the
Stop bits are always marks. The most common data format is eight bits. Each transmitted bit persists for a
period of 1/(Baud Rate). An on-chip dedicated
8-bit/16-bit Baud Rate Generator is used to derive
standard baud rate frequencies from the system
oscillator. See Table 21-5 for examples of baud rate
configurations.
21.1.1.2
Transmitting Data
A transmission is initiated by writing a character to the
TXREG register. If this is the first character, or the previous character has been completely flushed from the
TSR, the data in the TXREG is immediately transferred
to the TSR register. If the TSR still contains all or part of
a previous character, the new character data is held in
the TXREG until the Stop bit of the previous character
has been transmitted. The pending character in the
TXREG is then transferred to the TSR in one TCY
immediately following the Stop bit transmission. The
transmission of the Start bit, data bits and Stop bit
sequence commences immediately following the
transfer of the data to the TSR from the TXREG.
21.1.1.3
Transmit Data Polarity
The EUSART transmits and receives the LSb first. The
EUSART’s transmitter and receiver are functionally
independent, but share the same data format and baud
rate. Parity is not supported by the hardware, but can be
implemented in software and stored as the ninth data bit.
The polarity of the transmit data can be controlled with
the SCKP bit of the BAUDCON register. The default
state of this bit is ‘0’ which selects high true transmit Idle
and data bits. Setting the SCKP bit to ‘1’ will invert the
transmit data resulting in low true Idle and data bits. The
SCKP bit controls transmit data polarity in Asynchronous mode only. In Synchronous mode, the SCKP bit
has a different function. See Section 21.5.1.2 “Clock
Polarity”.
21.1.1
21.1.1.4
EUSART ASYNCHRONOUS
TRANSMITTER
The EUSART transmitter block diagram is shown in
Figure 21-1. The heart of the transmitter is the serial
Transmit Shift Register (TSR), which is not directly
accessible by software. The TSR obtains its data from
the transmit buffer, which is the TXREG register.
21.1.1.1
Enabling the Transmitter
The EUSART transmitter is enabled for asynchronous
operations by configuring the following three control bits:
• TXEN = 1
• SYNC = 0
• SPEN = 1
All other EUSART control bits are assumed to be in
their default state.
Setting the TXEN bit of the TXSTA register enables the
transmitter circuitry of the EUSART. Clearing the SYNC
bit of the TXSTA register configures the EUSART for
asynchronous operation. Setting the SPEN bit of the
RCSTA register enables the EUSART and automatically
configures the TX/CK I/O pin as an output. If the TX/CK
pin is shared with an analog peripheral, the analog I/O
function must be disabled by clearing the corresponding
ANSELx bit.
Note:
Transmit Interrupt Flag
The TXIF interrupt flag bit of the PIR1 register is set
whenever the EUSART transmitter is enabled and no
character is being held for transmission in the TXREG.
In other words, the TXIF bit is only clear when the TSR
is busy with a character and a new character has been
queued for transmission in the TXREG. The TXIF flag bit
is not cleared immediately upon writing TXREG. TXIF
becomes valid in the second instruction cycle following
the write execution. Polling TXIF immediately following
the TXREG write will return invalid results. The TXIF bit
is read-only, it cannot be set or cleared by software.
The TXIF interrupt can be enabled by setting the TXIE
interrupt enable bit of the PIE1 register. However, the
TXIF flag bit will be set whenever the TXREG is empty,
regardless of the state of the TXIE enable bit.
To use interrupts when transmitting data, set the TXIE
bit only when there is more data to send. Clear the
TXIE interrupt enable bit upon writing the last character
of the transmission to the TXREG.
The TXIF transmitter interrupt flag is set
when the TXEN enable bit is set.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 177
PIC12(L)F1571/2
21.1.1.5
TSR Status
21.1.1.7
The TRMT bit of the TXSTA register indicates the
status of the TSR register. This is a read-only bit. The
TRMT bit is set when the TSR register is empty and is
cleared when a character is transferred to the TSR
register from the TXREG. The TRMT bit remains clear
until all bits have been shifted out of the TSR register.
No interrupt logic is tied to this bit, so the user has to
poll this bit to determine the TSR status.
Note:
1.
2.
3.
The TSR register is not mapped in data
memory, so it is not available to the user.
21.1.1.6
4.
5.
Transmitting 9-Bit Characters
The EUSART supports 9-bit character transmissions.
When the TX9 bit of the TXSTA register is set, the
EUSART will shift nine bits out for each character transmitted. The TX9D bit of the TXSTA register is the ninth
and Most Significant data bit. When transmitting 9-bit
data, the TX9D data bit must be written before writing
the eight Least Significant bits into the TXREG. All nine
bits of data will be transferred to the TSR register
immediately after the TXREG is written.
6.
7.
8.
A special 9-Bit Address mode is available for use with
multiple receivers. See Section 21.1.2.7 “Address
Detection” for more information on this mode.
FIGURE 21-3:
Asynchronous Transmission Setup
Initialize the SPBRGH/SPBRGL register pair,
and the BRGH and BRG16 bits to achieve the
desired baud rate (see Section 21.4 “EUSART
Baud Rate Generator (BRG)”).
Enable the asynchronous serial port by clearing
the SYNC bit and setting the SPEN bit.
If 9-bit transmission is desired, set the TX9 control bit. A set ninth data bit will indicate that the
eight Least Significant data bits are an address
when the receiver is set for address detection.
Set the SCKP bit if inverted transmit is desired.
Enable the transmission by setting the TXEN
control bit. This will cause the TXIF interrupt bit
to be set.
If interrupts are desired, set the TXIE interrupt
enable bit of the PIE1 register. An interrupt will
occur immediately provided that the GIE and
PEIE bits of the INTCON register are also set.
If 9-bit transmission is selected, the ninth bit
should be loaded into the TX9D data bit.
Load 8-bit data into the TXREG register. This
will start the transmission.
ASYNCHRONOUS TRANSMISSION
Write to TXREG
Word 1
BRG Output
(Shift Clock)
Start bit
TX/CK Pin
bit 0
bit 1
bit 7/8
Stop bit
Word 1
1 TCY
TXIF bit
(Transmit Buffer
Reg. Empty Flag)
Word 1
Transmit Shift Reg.
TRMT bit
(Transmit Shift
Reg. Empty Flag)
FIGURE 21-4:
ASYNCHRONOUS TRANSMISSION (BACK-TO-BACK)
Write to TXREG
BRG Output
(Shift Clock)
Word 1
Word 2
Start bit
TX/CK Pin
bit 0
1 TCY
TXIF bit
(Transmit Buffer
Reg. Empty Flag)
bit 1
Word 1
bit 7/8
Stop bit
Start bit
Word 2
bit 0
1 TCY
Word 1
Transmit Shift Reg.
Word 2
Transmit Shift Reg.
TRMT bit
(Transmit Shift
Reg. Empty Flag)
Note: This timing diagram shows two consecutive transmissions.
DS40001723D-page 178
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
TABLE 21-1:
Name
BAUDCON
INTCON
PIE1
PIR1
RCSTA
SUMMARY OF REGISTERS ASSOCIATED WITH ASYNCHRONOUS TRANSMISSION
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Register
on Page
ABDOVF
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
186
GIE
PEIE
TMR0IE
INTE
IOCIE
TMR0IF
INTF
IOCIF
74
TMR1GIE
ADIE
RCIE(1)
TXIE(1)
—
—
TMR2IE
TMR1IE
75
TMR1GIF
ADIF
(1)
RCIF
TXIF
(1)
—
—
TMR2IF
TMR1IF
78
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
185*
SPBRGL
BRG<7:0>
187*
SPBRGH
BRG<15:8>
187*
TXREG
TXSTA
EUSART Transmit Data Register
CSRC
TX9
TXEN
177
SYNC
SENDB
BRGH
TRMT
TX9D
184
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used for asynchronous transmission.
* Page provides register information.
Note 1: PIC12(L)F1572 only.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 179
PIC12(L)F1571/2
21.1.2
EUSART ASYNCHRONOUS
RECEIVER
The Asynchronous mode is typically used in RS-232
systems. The receiver block diagram is shown in
Figure 21-2. The data is received on the RX/DT pin and
drives the data recovery block. The data recovery block
is actually a high-speed shifter operating at 16 times
the baud rate, whereas the serial Receive Shift
Register (RSR) operates at the bit rate. When all eight
or nine bits of the character have been shifted in, they
are immediately transferred to a two character
First-In-First-Out (FIFO) memory. The FIFO buffering
allows reception of two complete characters and the
start of a third character before software must start servicing the EUSART receiver. The FIFO and RSR registers are not directly accessible by software. Access to
the received data is via the RCREG register.
21.1.2.1
Enabling the Receiver
The EUSART receiver is enabled for asynchronous
operation by configuring the following three control bits:
• CREN = 1
• SYNC = 0
• SPEN = 1
All other EUSART control bits are assumed to be in
their default state.
Setting the CREN bit of the RCSTA register enables the
receiver circuitry of the EUSART. Clearing the SYNC bit
of the TXSTA register configures the EUSART for asynchronous operation. Setting the SPEN bit of the RCSTA
register enables the EUSART. The programmer must
set the corresponding TRIS bit to configure the RX/DT
I/O pin as an input.
Note:
If the RX/DT function is on an analog pin,
the corresponding ANSELx bit must be
cleared for the receiver to function.
21.1.2.2
Receiving Data
The receiver data recovery circuit initiates character
reception on the falling edge of the first bit. The first bit,
also known as the Start bit, is always a zero. The data
recovery circuit counts one-half bit time to the center of
the Start bit and verifies that the bit is still a zero. If it is
not a zero then the data recovery circuit aborts character reception, without generating an error, and resumes
looking for the falling edge of the Start bit. If the Start bit
zero verification succeeds, then the data recovery
circuit counts a full bit time to the center of the next bit.
The bit is then sampled by a majority detect circuit and
the resulting ‘0’ or ‘1’ is shifted into the RSR. This
repeats until all data bits have been sampled and
shifted into the RSR. One final bit time is measured and
the level sampled. This is the Stop bit, which is always
a ‘1’. If the data recovery circuit samples a ‘0’ in the
Stop bit position then a framing error is set for this character; otherwise, the framing error is cleared for this
character. See Section 21.1.2.4 “Receive Framing
Error” for more information on framing errors.
Immediately after all data bits and the Stop bit have
been received, the character in the RSR is transferred
to the EUSART receive FIFO and the RCIF interrupt
flag bit of the PIR1 register is set. The top character in
the FIFO is transferred out of the FIFO by reading the
RCREG register.
Note:
21.1.2.3
If the receive FIFO is overrun, no
additional characters will be received
until the overrun condition is cleared. See
Section 21.1.2.5 “Receive Overrun
Error” for more information on overrun
errors.
Receive Interrupts
The RCIF interrupt flag bit of the PIR1 register is set
whenever the EUSART receiver is enabled and there is
an unread character in the receive FIFO. The RCIF
interrupt flag bit is read-only, it cannot be set or cleared
by software.
RCIF interrupts are enabled by setting all of the
following bits:
• RCIE, Interrupt Enable bit of the PIE1 register
• PEIE, Peripheral Interrupt Enable bit of the
INTCON register
• GIE, Global Interrupt Enable bit of the INTCON
register
The RCIF interrupt flag bit will be set when there is an
unread character in the FIFO, regardless of the state of
interrupt enable bits.
DS40001723D-page 180
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
21.1.2.4
Receive Framing Error
Each character in the receive FIFO buffer has a
corresponding framing error status bit. A framing error
indicates that a Stop bit was not seen at the expected
time. The framing error status is accessed via the
FERR bit of the RCSTA register. The FERR bit represents the status of the top unread character in the
receive FIFO. Therefore, the FERR bit must be read
before reading the RCREG.
The FERR bit is read-only and only applies to the top
unread character in the receive FIFO. A framing error
(FERR = 1) does not preclude reception of additional
characters. It is not necessary to clear the FERR bit.
Reading the next character from the FIFO buffer will
advance the FIFO to the next character and the next
corresponding framing error.
The FERR bit can be forced clear by clearing the SPEN
bit of the RCSTA register which resets the EUSART.
Clearing the CREN bit of the RCSTA register does not
affect the FERR bit. A framing error by itself does not
generate an interrupt.
Note:
21.1.2.5
If all receive characters in the receive
FIFO have framing errors, repeated reads
of the RCREG will not clear the FERR bit.
Receive Overrun Error
The receive FIFO buffer can hold two characters. An
overrun error will be generated if a third character, in its
entirety, is received before the FIFO is accessed. When
this happens the OERR bit of the RCSTA register is set.
The characters already in the FIFO buffer can be read,
but no additional characters will be received until the
error is cleared. The error must be cleared by either
clearing the CREN bit of the RCSTA register or by
resetting the EUSART by clearing the SPEN bit of the
RCSTA register.
 2013-2015 Microchip Technology Inc.
21.1.2.6
Receiving 9-Bit Characters
The EUSART supports 9-bit character reception. When
the RX9 bit of the RCSTA register is set, the EUSART
will shift nine bits into the RSR for each character
received. The RX9D bit of the RCSTA register is the
ninth and Most Significant data bit of the top unread
character in the receive FIFO. When reading 9-bit data
from the receive FIFO buffer, the RX9D data bit must
be read before reading the eight Least Significant bits
from the RCREG.
21.1.2.7
Address Detection
A special Address Detection mode is available for use
when multiple receivers share the same transmission
line, such as in RS-485 systems. Address detection is
enabled by setting the ADDEN bit of the RCSTA
register.
Address detection requires 9-bit character reception.
When address detection is enabled, only characters
with the ninth data bit set will be transferred to the
receive FIFO buffer, thereby setting the RCIF interrupt
bit. All other characters will be ignored.
Upon receiving an address character, user software
determines if the address matches its own. Upon
address match, user software must disable address
detection by clearing the ADDEN bit before the next
Stop bit occurs. When user software detects the end of
the message, determined by the message protocol
used, software places the receiver back into the
Address Detection mode by setting the ADDEN bit.
DS40001723D-page 181
PIC12(L)F1571/2
21.1.2.8
Asynchronous Reception Setup
21.1.2.9
1.
Initialize the SPBRGH, SPBRGL register pair
and the BRGH and BRG16 bits to achieve the
desired baud rate (see Section 21.4 “EUSART
Baud Rate Generator (BRG)”).
2. Clear the ANSELx bit for the RX pin (if applicable).
3. Enable the serial port by setting the SPEN bit.
The SYNC bit must be clear for asynchronous
operation.
4. If interrupts are desired, set the RCIE bit of the
PIE1 register, and the GIE and PEIE bits of the
INTCON register.
5. If 9-bit reception is desired, set the RX9 bit.
6. Enable reception by setting the CREN bit.
7. The RCIF interrupt flag bit will be set when a
character is transferred from the RSR to the
receive buffer. An interrupt will be generated if
the RCIE interrupt enable bit was also set.
8. Read the RCSTA register to get the error flags
and, if 9-bit data reception is enabled, the ninth
data bit.
9. Get the received eight Least Significant data bits
from the receive buffer by reading the RCREG
register.
10. If an overrun occurred, clear the OERR flag by
clearing the CREN receiver enable bit.
FIGURE 21-5:
This mode would typically be used in RS-485 systems.
To set up an Asynchronous Reception with Address
Detect Enable:
1.
Initialize the SPBRGH/SPBRGL register pair,
and the BRGH and BRG16 bits to achieve the
desired baud rate (see Section 21.4 “EUSART
Baud Rate Generator (BRG)”).
2. Clear the ANSELx bit for the RX pin (if applicable).
3. Enable the serial port by setting the SPEN bit.
The SYNC bit must be clear for asynchronous
operation.
4. If interrupts are desired, set the RCIE bit of the
PIE1 register, and the GIE and PEIE bits of the
INTCON register.
5. Enable 9-bit reception by setting the RX9 bit.
6. Enable address detection by setting the ADDEN
bit.
7. Enable reception by setting the CREN bit.
8. The RCIF interrupt flag bit will be set when a
character with the ninth bit set is transferred
from the RSR to the receive buffer. An interrupt
will be generated if the RCIE interrupt enable bit
was also set.
9. Read the RCSTA register to get the error flags.
The ninth data bit will always be set.
10. Get the received eight Least Significant data bits
from the receive buffer by reading the RCREG
register. Software determines if this is the
device’s address.
11. If an overrun occurred, clear the OERR flag by
clearing the CREN receiver enable bit.
12. If the device has been addressed, clear the
ADDEN bit to allow all received data into the
receive buffer and generate interrupts.
ASYNCHRONOUS RECEPTION
Start
bit
RX/DT Pin
9-Bit Address Detection Mode Setup
Rcv Shift Reg.
Rcv Buffer Reg.
bit 0
bit 1
bit 7/8 Stop
bit
Start
bit
Word 1
RCREG
bit 0
bit 7/8 Stop
bit
Start
bit
bit 7/8
Stop
bit
Word 2
RCREG
RCIDL
Read Rcv
Buffer Reg. (RCREG)
RCIF
(Interrupt Flag)
OERR bit
CREN
Note:
This timing diagram shows three words appearing on the RX input. The RCREG (receive buffer) is read after the third word,
causing the OERR (overrun) bit to be set.
DS40001723D-page 182
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
TABLE 21-2:
Name
BAUDCON
INTCON
PIE1
PIR1
SUMMARY OF REGISTERS ASSOCIATED WITH ASYNCHRONOUS RECEPTION
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Register
on Page
ABDOVF
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
186
GIE
PEIE
TMR0IE
INTE
IOCIE
TMR0IF
INTF
IOCIF
74
TMR1GIE
ADIE
RCIE(1)
TXIE(1)
—
—
TMR2IE
TMR1IE
75
ADIF
(1)
(1)
—
—
TMR2IF
TMR1IF
TMR1GIF
RCIF
RCREG
TXIF
EUSART Receive Data Register
RCSTA
SPEN
RX9
SREN
CREN
SPBRGL
FERR
OERR
RX9D
BRG<7:0>
SPBRGH
TXSTA
ADDEN
TX9
TXEN
SYNC
SENDB
185*
187*
BRG<15:8>
CSRC
78
180*
187*
BRGH
TRMT
TX9D
184
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used for asynchronous reception.
* Page provides register information.
Note 1: PIC12(L)F1572 only.
21.2
Clock Accuracy with
Asynchronous Operation
The factory calibrates the Internal Oscillator Block
(INTOSC) output. However, the INTOSC frequency
may drift as VDD or temperature changes, and this
directly affects the asynchronous baud rate.
 2013-2015 Microchip Technology Inc.
The Auto-Baud Detect feature (see Section 21.4.1
“Auto-Baud Detect”) can be used to compensate for
changes in the INTOSC frequency.
There may not be fine enough resolution when
adjusting the Baud Rate Generator to compensate for
a gradual change in the peripheral clock frequency.
DS40001723D-page 183
PIC12(L)F1571/2
21.3
Register Definitions: EUSART Control
REGISTER 21-1:
TXSTA: TRANSMIT STATUS AND CONTROL REGISTER
R/W-/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R-1/1
R/W-0/0
CSRC
TX9
TXEN(1)
SYNC
SENDB
BRGH
TRMT
TX9D
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
CSRC: Clock Source Select bit
Asynchronous mode:
Don’t care.
Synchronous mode:
1 = Master mode (clock generated internally from BRG)
0 = Slave mode (clock from external source)
bit 6
TX9: 9-Bit Transmit Enable bit
1 = Selects 9-bit transmission
0 = Selects 8-bit transmission
bit 5
TXEN: Transmit Enable bit(1)
1 = Transmit is enabled
0 = Transmit is disabled
bit 4
SYNC: EUSART Mode Select bit
1 = Synchronous mode
0 = Asynchronous mode
bit 3
SENDB: Send Break Character bit
Asynchronous mode:
1 = Sends Sync Break on next transmission (cleared by hardware upon completion)
0 = Sync Break transmission completed
Synchronous mode:
Don’t care.
bit 2
BRGH: High Baud Rate Select bit
Asynchronous mode:
1 = High speed
0 = Low speed
Synchronous mode:
Unused in this mode.
bit 1
TRMT: Transmit Shift Register Status bit
1 = TSR is empty
0 = TSR is full
bit 0
TX9D: Ninth bit of Transmit Data
Can be address/data bit or a parity bit.
Note 1:
SREN/CREN overrides TXEN in Sync mode.
DS40001723D-page 184
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
REGISTER 21-2:
RCSTA: RECEIVE STATUS AND CONTROL REGISTER
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R-0/0
R-0/0
R-0/0
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
SPEN: Serial Port Enable bit
1 = Serial port is enabled (configures RX/DT and TX/CK pins as serial port pins)
0 = Serial port is disabled (held in Reset)
bit 6
RX9: 9-Bit Receive Enable bit
1 = Selects 9-bit reception
0 = Selects 8-bit reception
bit 5
SREN: Single Receive Enable bit
Asynchronous mode:
Don’t care.
Synchronous mode – Master:
1 = Enables single receive
0 = Disables single receive
This bit is cleared after reception is complete.
Synchronous mode – Slave:
Don’t care.
bit 4
CREN: Continuous Receive Enable bit
Asynchronous mode:
1 = Enables receiver
0 = Disables receiver
Synchronous mode:
1 = Enables continuous receive until enable bit CREN is cleared (CREN overrides SREN)
0 = Disables continuous receive
bit 3
ADDEN: Address Detect Enable bit
Asynchronous mode 9-bit (RX9 = 1):
1 = Enables address detection, enables interrupt and loads the receive buffer when RSR<8> is set
0 = Disables address detection, all bytes are received and ninth bit can be used as parity bit
Asynchronous mode 8-bit (RX9 = 0):
Don’t care.
bit 2
FERR: Framing Error bit
1 = Framing error (can be updated by reading RCREG register and receiving next valid byte)
0 = No framing error
bit 1
OERR: Overrun Error bit
1 = Overrun error (can be cleared by clearing bit, CREN)
0 = No overrun error
bit 0
RX9D: Ninth Bit of Received Data bit
This can be address/data bit or a parity bit and must be calculated by user firmware.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 185
PIC12(L)F1571/2
REGISTER 21-3:
BAUDCON: BAUD RATE CONTROL REGISTER
R-0/0
R-1/1
U-0
R/W-0/0
R/W-0/0
U-0
R/W-0/0
R/W-0/0
ABDOVF
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
ABDOVF: Auto-Baud Detect Overflow bit
Asynchronous mode:
1 = Auto-baud timer overflowed
0 = Auto-baud timer did not overflow
Synchronous mode:
Don’t care.
bit 6
RCIDL: Receive Idle Flag bit
Asynchronous mode:
1 = Receiver is Idle
0 = Start bit has been received and the receiver is receiving
Synchronous mode:
Don’t care.
bit 5
Unimplemented: Read as ‘0’
bit 4
SCKP: Synchronous Clock Polarity Select bit
Asynchronous mode:
1 = Transmits inverted data to the TX/CK pin
0 = Transmits non-inverted data to the TX/CK pin
Synchronous mode:
1 = Data is clocked on rising edge of the clock
0 = Data is clocked on falling edge of the clock
bit 3
BRG16: 16-Bit Baud Rate Generator bit
1 = 16-bit Baud Rate Generator is used
0 = 8-bit Baud Rate Generator is used
bit 2
Unimplemented: Read as ‘0’
bit 1
WUE: Wake-up Enable bit
Asynchronous mode:
1 = Receiver is waiting for a falling edge; no character will be received, RCIF bit will be set, WUE will
automatically clear after RCIF is set
0 = Receiver is operating normally
Synchronous mode:
Don’t care
bit 0
ABDEN: A.uto-Baud Detect Enable bit
Asynchronous mode:
1 = Auto-Baud Detect mode is enabled (clears when auto-baud is complete)
0 = Auto-Baud Detect mode is disabled
Synchronous mode:
Don’t care.
DS40001723D-page 186
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
21.4
EUSART Baud Rate Generator
(BRG)
The Baud Rate Generator (BRG) is an 8-bit or 16-bit
timer that is dedicated to the support of both the asynchronous and synchronous EUSART operation. By
default, the BRG operates in 8-bit mode. Setting the
BRG16 bit of the BAUDCON register selects 16-bit
mode.
The SPBRGH/SPBRGL register pair determines the
period of the free-running baud rate timer. In Asynchronous mode, the multiplier of the baud rate period is
determined by both the BRGH bit of the TXSTA register
and the BRG16 bit of the BAUDCON register. In
Synchronous mode, the BRGH bit is ignored.
Table 21-3 contains the formulas for determining the
baud rate. Example 21-1 provides a sample calculation
for determining the baud rate and baud rate error.
Typical baud rates and error values for various
Asynchronous modes have been computed for your
convenience and are shown in Table 21-3. It may be
advantageous to use the high baud rate (BRGH = 1) or
the 16-bit BRG (BRG16 = 1) to reduce the baud rate
error. The 16-bit BRG mode is used to achieve slow
baud rates for fast oscillator frequencies.
EXAMPLE 21-1:
CALCULATING BAUD
RATE ERROR
For a device with FOSC of 16 MHz, desired baud rate
of 9600, Asynchronous mode, 8-bit BRG:
F OS C
Desired Baud Rate = -----------------------------------------------------------------------64  [SPBRGH:SPBRGL] + 1 
Solving for SPBRGH:SPBRGL:
FOSC
--------------------------------------------Desired Baud Rate
X = --------------------------------------------- – 1
64
16000000
-----------------------9600
= ------------------------ – 1
64
=  25.042  = 25
16000000
Calculated Baud Rate = --------------------------64  25 + 1 
= 9615
Calc. Baud Rate – Desired Baud Rate
Error = -------------------------------------------------------------------------------------------Desired Baud Rate
 9615 – 9600 
= ---------------------------------- = 0.16%
9600
Writing a new value to the SPBRGH/SPBRGL register
pair causes the BRG timer to be reset (or cleared). This
ensures that the BRG does not wait for a timer overflow
before outputting the new baud rate.
If the system clock is changed during an active receive
operation, a receive error or data loss may result. To
avoid this problem, check the status of the RCIDL bit to
make sure that the receive operation is Idle before
changing the system clock.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 187
PIC12(L)F1571/2
TABLE 21-3:
BAUD RATE FORMULAS
Configuration Bits
SYNC
BRG16
BRGH
BRG/EUSART Mode
Baud Rate Formula
FOSC/[64 (n+1)]
0
0
0
8-bit/Asynchronous
0
0
1
8-bit/Asynchronous
0
1
0
16-bit/Asynchronous
0
1
1
16-bit/Asynchronous
1
0
x
8-bit/Synchronous
1
1
x
16-bit/Synchronous
FOSC/[16 (n+1)]
FOSC/[4 (n+1)]
Legend: x = Don’t care; n = value of SPBRGH/SPBRGL register pair.
TABLE 21-4:
Name
BAUDCON
RCSTA
SUMMARY OF REGISTERS ASSOCIATED WITH THE BAUD RATE GENERATOR
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Register
on Page
ABDOVF
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
186
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
SPBRGL
BRG<7:0>
SPBRGH
TXSTA
BRG<15:8>
CSRC
TX9
TXEN
SYNC
SENDB
185
187*
187*
BRGH
TRMT
TX9D
184
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used for the Baud Rate Generator.
* Page provides register information.
DS40001723D-page 188
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
TABLE 21-5:
BAUD RATES FOR ASYNCHRONOUS MODES
SYNC = 0, BRGH = 0, BRG16 = 0
BAUD
RATE
FOSC = 20.000 MHz
FOSC = 18.432 MHz
FOSC = 16.000 MHz
FOSC = 11.0592 MHz
Actual
Rate
%
Error
SPBRG
Value
(decimal)
Actual
Rate
%
Error
SPBRG
Value
(decimal)
Actual
Rate
%
Error
SPBRG
Value
(decimal)
Actual
Rate
%
Error
SPBRG
Value
(decimal)
300
—
—
—
—
—
—
—
—
—
—
—
—
1200
1221
1.73
255
1200
0.00
239
1202
0.16
207
1200
0.00
143
2400
2404
0.16
129
2400
0.00
119
2404
0.16
103
2400
0.00
71
9600
9470
-1.36
32
9600
0.00
29
9615
0.16
25
9600
0.00
17
10417
10417
0.00
29
10286
-1.26
27
10417
0.00
23
10165
-2.42
16
19.2k
19.53k
1.73
15
19.20k
0.00
14
19.23k
0.16
12
19.20k
0.00
8
57.6k
—
—
—
57.60k
0.00
7
—
—
—
57.60k
0.00
2
115.2k
—
—
—
—
—
—
—
—
—
—
—
—
SYNC = 0, BRGH = 0, BRG16 = 0
BAUD
RATE
FOSC = 8.000 MHz
Actual
Rate
%
Error
SPBRG
Value
(decimal)
FOSC = 4.000 MHz
Actual
Rate
%
Error
SPBRG
Value
(decimal)
FOSC = 3.6864 MHz
Actual
Rate
%
Error
SPBRG
Value
(decimal)
FOSC = 1.000 MHz
Actual
Rate
%
Error
SPBRG
Value
(decimal)
300
—
—
—
300
0.16
207
300
0.00
191
300
0.16
51
1200
1202
0.16
103
1202
0.16
51
1200
0.00
47
1202
0.16
12
2400
2404
0.16
51
2404
0.16
25
2400
0.00
23
—
—
—
9600
9615
0.16
12
—
—
—
9600
0.00
5
—
—
—
10417
10417
0.00
11
10417
0.00
5
—
—
—
—
—
—
19.2k
—
—
—
—
—
—
19.20k
0.00
2
—
—
—
57.6k
—
—
—
—
—
—
57.60k
0.00
0
—
—
—
115.2k
—
—
—
—
—
—
—
—
—
—
—
—
SYNC = 0, BRGH = 1, BRG16 = 0
BAUD
RATE
FOSC = 20.000 MHz
Actual
Rate
%
Error
SPBRG
Value
(decimal)
FOSC = 18.432 MHz
Actual
Rate
%
Error
SPBRG
Value
(decimal)
FOSC = 16.000 MHz
Actual
Rate
%
Error
SPBRG
Value
(decimal)
FOSC = 11.0592 MHz
Actual
Rate
%
Error
SPBRG
Value
(decimal)
300
—
—
—
—
—
—
—
—
—
—
—
—
1200
—
—
—
—
—
—
—
—
—
—
—
—
2400
—
—
—
—
—
—
—
—
—
—
—
—
9600
9615
0.16
129
9600
0.00
119
9615
0.16
103
9600
0.00
71
10417
10417
0.00
119
10378
-0.37
110
10417
0.00
95
10473
0.53
65
19.2k
19.23k
0.16
64
19.20k
0.00
59
19.23k
0.16
51
19.20k
0.00
35
57.6k
56.82k
-1.36
21
57.60k
0.00
19
58.82k
2.12
16
57.60k
0.00
11
115.2k
113.64k
-1.36
10
115.2k
0.00
9
111.1k
-3.55
8
115.2k
0.00
5
 2013-2015 Microchip Technology Inc.
DS40001723D-page 189
PIC12(L)F1571/2
TABLE 21-5:
BAUD RATES FOR ASYNCHRONOUS MODES (CONTINUED)
SYNC = 0, BRGH = 1, BRG16 = 0
BAUD
RATE
FOSC = 8.000 MHz
Actual
Rate
%
Error
SPBRG
Value
(decimal)
FOSC = 4.000 MHz
Actual
Rate
%
Error
SPBRG
Value
(decimal)
FOSC = 3.6864 MHz
Actual
Rate
%
Error
SPBRG
Value
(decimal)
FOSC = 1.000 MHz
Actual
Rate
%
Error
SPBRG
Value
(decimal)
207
300
—
—
—
—
—
—
—
—
—
300
0.16
1200
—
—
—
1202
0.16
207
1200
0.00
191
1202
0.16
51
2400
2404
0.16
207
2404
0.16
103
2400
0.00
95
2404
0.16
25
9600
9615
0.16
51
9615
0.16
25
9600
0.00
23
—
—
—
10417
10417
0.00
47
10417
0.00
23
10473
0.53
21
10417
0.00
5
19.2k
19231
0.16
25
19.23k
0.16
12
19.2k
0.00
11
—
—
—
57.6k
55556
-3.55
8
—
—
—
57.60k
0.00
3
—
—
—
115.2k
—
—
—
—
—
—
115.2k
0.00
1
—
—
—
SYNC = 0, BRGH = 0, BRG16 = 1
BAUD
RATE
FOSC = 20.000 MHz
Actual
Rate
FOSC = 18.432 MHz
FOSC = 16.000 MHz
FOSC = 11.0592 MHz
%
Error
SPBRG
Value
(decimal)
Actual
Rate
%
Error
SPBRG
Value
(decimal)
Actual
Rate
%
Error
SPBRG
Value
(decimal)
Actual
Rate
%
Error
SPBRG
Value
(decimal)
300
300.0
-0.01
4166
300.0
0.00
3839
300.03
0.01
3332
300.0
0.00
2303
1200
1200
-0.03
1041
1200
0.00
959
1200.5
0.04
832
1200
0.00
575
2400
2399
-0.03
520
2400
0.00
479
2398
-0.08
416
2400
0.00
287
9600
9615
0.16
129
9600
0.00
119
9615
0.16
103
9600
0.00
71
10417
10417
0.00
119
10378
-0.37
110
10417
0.00
95
10473
0.53
65
19.2k
19.23k
0.16
64
19.20k
0.00
59
19.23k
0.16
51
19.20k
0.00
35
57.6k
56.818
-1.36
21
57.60k
0.00
19
58.82k
2.12
16
57.60k
0.00
11
115.2k
113.636
-1.36
10
115.2k
0.00
9
111.11k
-3.55
8
115.2k
0.00
5
SYNC = 0, BRGH = 0, BRG16 = 1
BAUD
RATE
FOSC = 8.000 MHz
Actual
Rate
FOSC = 4.000 MHz
FOSC = 3.6864 MHz
%
Error
SPBRG
Value
(decimal)
Actual
Rate
%
Error
SPBRG
Value
(decimal)
Actual
Rate
%
Error
FOSC = 1.000 MHz
SPBRG
Value
(decimal)
Actual
Rate
%
Error
SPBRG
Value
(decimal)
300
299.9
-0.02
1666
300.1
0.04
832
300.0
0.00
767
300.5
0.16
207
1200
1199
-0.08
416
1202
0.16
207
1200
0.00
191
1202
0.16
51
2400
2404
0.16
207
2404
0.16
103
2400
0.00
95
2404
0.16
25
9600
9615
0.16
51
9615
0.16
25
9600
0.00
23
—
—
—
10417
10417
0.00
47
10417
0.00
23
10473
0.53
21
10417
0.00
5
19.2k
19.23k
0.16
25
19.23k
0.16
12
19.20k
0.00
11
—
—
—
57.6k
55556
-3.55
8
—
—
—
57.60k
0.00
3
—
—
—
115.2k
—
—
—
—
—
—
115.2k
0.00
1
—
—
—
DS40001723D-page 190
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
TABLE 21-5:
BAUD RATES FOR ASYNCHRONOUS MODES (CONTINUED)
SYNC = 0, BRGH = 1, BRG16 = 1 or SYNC = 1, BRG16 = 1
BAUD
RATE
FOSC = 20.000 MHz
Actual
Rate
FOSC = 18.432 MHz
%
Error
SPBRG
Value
(decimal)
Actual
Rate
%
Error
SPBRG
Value
(decimal)
FOSC = 16.000 MHz
Actual
Rate
FOSC = 11.0592 MHz
%
Error
SPBRG
Value
(decimal)
Actual
Rate
%
Error
SPBRG
Value
(decimal)
300
300.0
0.00
16665
300.0
0.00
15359
300.0
0.00
13332
300.0
0.00
9215
1200
1200
-0.01
4166
1200
0.00
3839
1200.1
0.01
3332
1200
0.00
2303
2400
2400
0.02
2082
2400
0.00
1919
2399.5
-0.02
1666
2400
0.00
1151
9600
9597
-0.03
520
9600
0.00
479
9592
-0.08
416
9600
0.00
287
10417
10417
0.00
479
10425
0.08
441
10417
0.00
383
10433
0.16
264
19.2k
19.23k
0.16
259
19.20k
0.00
239
19.23k
0.16
207
19.20k
0.00
143
57.6k
57.47k
-0.22
86
57.60k
0.00
79
57.97k
0.64
68
57.60k
0.00
47
115.2k
116.3k
0.94
42
115.2k
0.00
39
114.29k
-0.79
34
115.2k
0.00
23
SYNC = 0, BRGH = 1, BRG16 = 1 or SYNC = 1, BRG16 = 1
BAUD
RATE
FOSC = 8.000 MHz
Actual
Rate
FOSC = 4.000 MHz
FOSC = 3.6864 MHz
FOSC = 1.000 MHz
%
Error
SPBRG
Value
(decimal)
Actual
Rate
%
Error
SPBRG
Value
(decimal)
Actual
Rate
%
Error
SPBRG
Value
(decimal)
Actual
Rate
%
Error
SPBRG
Value
(decimal)
300
300.0
0.00
6666
300.0
0.01
3332
300.0
0.00
3071
300.1
0.04
832
1200
1200
-0.02
1666
1200
0.04
832
1200
0.00
767
1202
0.16
207
2400
2401
0.04
832
2398
0.08
416
2400
0.00
383
2404
0.16
103
9600
9615
0.16
207
9615
0.16
103
9600
0.00
95
9615
0.16
25
10417
10417
0
191
10417
0.00
95
10473
0.53
87
10417
0.00
23
19.2k
19.23k
0.16
103
19.23k
0.16
51
19.20k
0.00
47
19.23k
0.16
12
57.6k
57.14k
-0.79
34
58.82k
2.12
16
57.60k
0.00
15
—
—
—
115.2k
117.6k
2.12
16
111.1k
-3.55
8
115.2k
0.00
7
—
—
—
 2013-2015 Microchip Technology Inc.
DS40001723D-page 191
PIC12(L)F1571/2
21.4.1
AUTO-BAUD DETECT
The EUSART module supports automatic detection
and calibration of the baud rate.
In the Auto-Baud Detect (ABD) mode, the clock to the
BRG is reversed. Rather than the BRG clocking the
incoming RX signal, the RX signal is timing the BRG.
The Baud Rate Generator is used to time the period of
a received 55h (ASCII “U”), which is the Sync character
for the LIN bus. The unique feature of this character is
that it has five rising edges, including the Stop bit edge.
Setting the ABDEN bit of the BAUDCON register starts
the auto-baud calibration sequence (Figure 21-6).
While the ABD sequence takes place, the EUSART
state machine is held in Idle. On the first rising edge of
the receive line, after the Start bit, the SPBRG begins
counting up using the BRG counter clock as shown in
Table 21-6. The fifth rising edge will occur on the RX pin
at the end of the eighth bit period. At that time, an
accumulated value totaling the proper BRG period is
left in the SPBRGH/SPBRGL register pair, the ABDEN
bit is automatically cleared and the RCIF interrupt flag
is set. The value in the RCREG needs to be read to
clear the RCIF interrupt. RCREG content should be
discarded. When calibrating for modes that do not use
the SPBRGH register, the user can verify that the
SPBRGL register did not overflow by checking for 00h
in the SPBRGH register.
The BRG auto-baud clock is determined by the BRG16
and BRGH bits, as shown in Table 21-6. During ABD,
both the SPBRGH and SPBRGL registers are used as
a 16-bit counter, independent of the BRG16 bit setting.
While calibrating the baud rate period, the SPBRGH
FIGURE 21-6:
BRG Value
and SPBRGL registers are clocked at 1/8th the BRG
base clock rate. The resulting byte measurement is the
average bit time when clocked at full speed.
Note 1: If the WUE bit is set with the ABDEN bit,
Auto-Baud Detection will occur on the
byte following the Break character
(see Section 21.4.3 “Auto-Wake-up on
Break”).
2: It is up to the user to determine that the
incoming character baud rate is within the
range of the selected BRG clock source.
Some combinations of oscillator frequency
and EUSART baud rates are not possible.
3: During the auto-baud process, the
auto-baud counter starts counting at 1.
Upon completion of the auto-baud
sequence, to achieve maximum accuracy,
subtract 1 from the SPBRGH:SPBRGL
register pair.
TABLE 21-6:
BRG COUNTER CLOCK RATES
BRG16
BRGH
BRG Base
Clock
BRG ABD
Clock
0
0
FOSC/64
FOSC/512
0
1
FOSC/16
FOSC/128
1
0
FOSC/16
FOSC/128
1
FOSC/4
FOSC/32
1
Note:
During the ABD sequence, the SPBRGL
and SPBRGH registers are both used as a
16-bit counter, independent of the BRG16
setting.
AUTOMATIC BAUD RATE CALIBRATION
XXXXh
0000h
001Ch
Start
RX Pin
Edge #1
bit 1
bit 0
Edge #2
bit 3
bit 2
Edge #3
bit 5
bit 4
Edge #4
bit 7
bit 6
Edge #5
Stop bit
BRG Clock
Auto Cleared
Set by User
ABDEN bit
RCIDL
RCIF bit
(Interrupt)
Read
RCREG
SPBRGL
XXh
1Ch
SPBRGH
XXh
00h
Note 1:
The ABD sequence requires the EUSART module to be configured in Asynchronous mode.
DS40001723D-page 192
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
21.4.2
AUTO-BAUD OVERFLOW
21.4.3.1
Special Considerations
During the course of Automatic Baud Detection, the
ABDOVF bit of the BAUDCON register will be set if the
baud rate counter overflows before the fifth rising edge
is detected on the RX pin. The ABDOVF bit indicates
that the counter has exceeded the maximum count that
can fit in the 16 bits of the SPBRGH:SPBRGL register
pair. The overflow condition will set the RCIF flag. The
counter continues to count until the fifth rising edge is
detected on the RX pin. The RCIDL bit will remain false
(‘0’) until the fifth rising edge, at which time, the RDICL
bit will set. If the RCREG is read after the overflow
occurs, but before the fifth rising edge, the fifth rising
edge will set the RCIF again.
Break Character
Terminating the auto-baud process early to clear an
overflow condition will prevent proper detection of the
Sync character fifth rising edge. If any falling edges of
the Sync character have not yet occurred when the
ABDEN bit is cleared, then those will be falsely
detected as Start bits. The following steps are
recommended to clear the overflow condition:
Therefore, the initial character in the transmission must
be all ‘0’s. This must be ten or more bit times; 13-bit
times are recommended for LIN bus or any number of
bit times for standard RS-232 devices.
1.
2.
3.
Read RCREG to clear RCIF.
If RCIDL is zero, then wait for RCIF and repeat
Step 1.
Clear the ABDOVF bit.
21.4.3
AUTO-WAKE-UP ON BREAK
During Sleep mode, all clocks to the EUSART are
suspended. Because of this, the Baud Rate Generator
is inactive and a proper character reception cannot be
performed. The auto-wake-up feature allows the
controller to wake-up due to activity on the RX/DT line.
This feature is available only in Asynchronous mode.
The auto-wake-up feature is enabled by setting the WUE
bit of the BAUDCON register. Once set, the normal
receive sequence on RX/DT is disabled, and the
EUSART remains in an Idle state, monitoring for a
wake-up event independent of the CPU mode. A
wake-up event consists of a high-to-low transition on the
RX/DT line. (This coincides with the start of a Sync Break
or a wake-up signal character for the LIN protocol.)
To avoid character errors or character fragments during
a wake-up event, the wake-up character must be all
zeros.
When the wake-up is enabled, the function works
independent of the low time on the data stream. If the
WUE bit is set and a valid non-zero character is
received, the low time from the Start bit to the first rising
edge will be interpreted as the wake-up event. The
remaining bits in the character will be received as a
fragmented character and subsequent characters can
result in framing or overrun errors.
Oscillator Start-up Time
Oscillator start-up time must be considered, especially
in applications using oscillators with longer start-up
intervals (i.e., LP, XT or HS/PLL mode). The Sync
Break (or wake-up signal) character must be of
sufficient length, and be followed by a sufficient
interval, to allow enough time for the selected oscillator
to start and provide proper initialization of the EUSART.
WUE Bit
The wake-up event causes a receive interrupt by
setting the RCIF bit. The WUE bit is cleared in
hardware by a rising edge on RX/DT. The interrupt
condition is then cleared in software by reading the
RCREG register and discarding its contents.
To ensure that no actual data is lost, check the RCIDL
bit to verify that a receive operation is not in process
before setting the WUE bit. If a receive operation is not
occurring, the WUE bit may then be set just prior to
entering the Sleep mode.
The EUSART module generates an RCIF interrupt
coincident with the wake-up event. The interrupt is
generated synchronously to the Q clocks in normal CPU
operating modes (Figure 21-7), and asynchronously if
the device is in Sleep mode (Figure 21-8). The interrupt
condition is cleared by reading the RCREG register.
The WUE bit is automatically cleared by the low-to-high
transition on the RX line at the end of the Break. This
signals to the user that the Break event is over. At this
point, the EUSART module is in Idle mode waiting to
receive the next character.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 193
PIC12(L)F1571/2
FIGURE 21-7:
AUTO-WAKE-UP BIT (WUE) TIMING DURING NORMAL OPERATION
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1Q2 Q3 Q4
OSC1
WUE bit
Auto-Cleared
Bit Set by User
RX/DT
Line
RCIF
Note 1:
Cleared due to User Read of RCREG
The EUSART remains in Idle while the WUE bit is set.
FIGURE 21-8:
AUTO-WAKE-UP BIT (WUE) TIMINGS DURING SLEEP
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
Q1
Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1
WUE bit
Auto Cleared
Bit Set by User
RX/DT
Line
Note 1
RCIF
Sleep Command Executed
Note 1:
2:
Sleep Ends
Cleared due to User Read of RCREG
If the wake-up event requires long oscillator warm-up time, the automatic clearing of the WUE bit can occur while the stposc signal
is still active. This sequence should not depend on the presence of Q clocks.
The EUSART remains in Idle while the WUE bit is set.
DS40001723D-page 194
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
21.4.4
BREAK CHARACTER SEQUENCE
The EUSART module has the capability of sending the
special Break character sequences that are required by
the LIN bus standard. A Break character consists of a
Start bit, followed by twelve ‘0’ bits and a Stop bit.
To send a Break character, set the SENDB and TXEN
bits of the TXSTA register. The Break character transmission is then initiated by a write to the TXREG. The
value of data written to TXREG will be ignored and all
‘0’s will be transmitted.
The SENDB bit is automatically reset by hardware after
the corresponding Stop bit is sent. This allows the user
to preload the transmit FIFO with the next transmit byte
following the Break character (typically, the Sync
character in the LIN specification).
The TRMT bit of the TXSTA register indicates when the
transmit operation is active or idle, just as it does during
normal transmission. See Figure 21-9 for the timing of
the Break character sequence.
21.4.4.1
Break and Sync Transmit Sequence
The following sequence will start a message frame
header made up of a Break, followed by an auto-baud
Sync byte. This sequence is typical of a LIN bus master.
1.
2.
3.
4.
5.
21.4.5
RECEIVING A BREAK CHARACTER
The Enhanced USART module can receive a Break
character in two ways.
The first method to detect a Break character uses the
FERR bit of the RCSTA register and the received data
as indicated by RCREG. The Baud Rate Generator is
assumed to have been initialized to the expected baud
rate.
A Break character has been received when:
• RCIF bit is set
• FERR bit is set
• RCREG = 00h
The second method uses the auto-wake-up feature
described in Section 21.4.3 “Auto-Wake-up on
Break”. By enabling this feature, the EUSART will
sample the next two transitions on RX/DT, cause an
RCIF interrupt and receive the next data byte followed
by another interrupt.
Note that following a Break character, the user will
typically want to enable the Auto-Baud Detect feature.
For both methods, the user can set the ABDEN bit of
the BAUDCON register before placing the EUSART in
Sleep mode.
Configure the EUSART for the desired mode.
Set the TXEN and SENDB bits to enable the
Break sequence.
Load the TXREG with a dummy character to
initiate transmission (the value is ignored).
Write ‘55h’ to TXREG to load the Sync character
into the transmit FIFO buffer.
After the Break has been sent, the SENDB bit is
reset by hardware and the Sync character is
then transmitted.
When the TXREG becomes empty, as indicated by the
TXIF, the next data byte can be written to TXREG.
FIGURE 21-9:
Write to TXREG
SEND BREAK CHARACTER SEQUENCE
Dummy Write
BRG Output
(Shift Clock)
TX (pin)
Start bit
bit 0
bit 1
bit 11
Stop bit
Break
TXIF bit
(Transmit
Interrupt Flag)
TRMT bit
(Transmit Shift
Empty Flag)
SENDB
(send Break
control bit)
 2013-2015 Microchip Technology Inc.
SENDB Sampled Here
Auto Cleared
DS40001723D-page 195
PIC12(L)F1571/2
21.5
EUSART Synchronous Mode
Synchronous serial communications are typically used
in systems with a single master and one or more
slaves. The master device contains the necessary
circuitry for baud rate generation and supplies the clock
for all devices in the system. Slave devices can take
advantage of the master clock by eliminating the
internal clock generation circuitry.
There are two signal lines in Synchronous mode: a
bidirectional data line and a clock line. Slaves use the
external clock supplied by the master to shift the serial
data into and out of their respective Receive and Transmit Shift registers. Since the data line is bidirectional,
synchronous operation is half-duplex only. Half-duplex
refers to the fact that master and slave devices can
receive and transmit data but not both simultaneously.
The EUSART can operate as either a master or slave
device.
Start and Stop bits are not used in synchronous
transmissions.
21.5.1
SYNCHRONOUS MASTER MODE
The following bits are used to configure the EUSART
for synchronous master operation:
•
•
•
•
•
SYNC = 1
CSRC = 1
SREN = 0 (for transmit); SREN = 1 (for receive)
CREN = 0 (for transmit); CREN = 1 (for receive)
SPEN = 1
Setting the SYNC bit of the TXSTA register configures
the device for synchronous operation. Setting the CSRC
bit of the TXSTA register configures the device as a
master. Clearing the SREN and CREN bits of the RCSTA
register ensures that the device is in the Transmit mode,
otherwise the device will be configured to receive. Setting
the SPEN bit of the RCSTA register enables the
EUSART.
21.5.1.1
Master Clock
Synchronous data transfers use a separate clock line,
which is synchronous with the data. A device configured as a master transmits the clock on the TX/CK line.
The TX/CK pin output driver is automatically enabled
when the EUSART is configured for synchronous
transmit or receive operation. Serial data bits change
on the leading edge to ensure they are valid at the trailing edge of each clock. One clock cycle is generated
for each data bit. Only as many clock cycles are
generated as there are data bits.
DS40001723D-page 196
21.5.1.2
Clock Polarity
A clock polarity option is provided for Microwire
compatibility. Clock polarity is selected with the SCKP
bit of the BAUDCON register. Setting the SCKP bit sets
the clock Idle state as high. When the SCKP bit is set,
the data changes on the falling edge of each clock.
Clearing the SCKP bit sets the Idle state as low. When
the SCKP bit is cleared, the data changes on the rising
edge of each clock.
21.5.1.3
Synchronous Master Transmission
Data is transferred out of the device on the RX/DT pin.
The RX/DT and TX/CK pin output drivers are automatically enabled when the EUSART is configured for
synchronous master transmit operation.
A transmission is initiated by writing a character to the
TXREG register. If the TSR still contains all or part of a
previous character the new character data is held in the
TXREG until the last bit of the previous character has
been transmitted. If this is the first character, or the
previous character has been completely flushed from
the TSR, the data in the TXREG is immediately transferred to the TSR. The transmission of the character
commences immediately following the transfer of the
data to the TSR from the TXREG.
Each data bit changes on the leading edge of the
master clock and remains valid until the subsequent
leading clock edge.
Note:
The TSR register is not mapped in data
memory, so it is not available to the user.
21.5.1.4
Synchronous Master Transmission
Setup
1.
2.
3.
4.
5.
6.
7.
8.
Initialize the SPBRGH, SPBRGL register pair
and the BRGH and BRG16 bits to achieve the
desired baud rate (see Section 21.4 “EUSART
Baud Rate Generator (BRG)”).
Enable the synchronous master serial port by
setting bits, SYNC, SPEN and CSRC.
Disable Receive mode by clearing bits, SREN
and CREN.
Enable Transmit mode by setting the TXEN bit.
If 9-bit transmission is desired, set the TX9 bit.
If interrupts are desired, set the TXIE bit of the
PIE1 register, and the GIE and PEIE bits of the
INTCON register.
If 9-bit transmission is selected, the ninth bit
should be loaded in the TX9D bit.
Start transmission by loading data to the TXREG
register.
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
FIGURE 21-10:
SYNCHRONOUS TRANSMISSION
RX/DT
Pin
bit 0
bit 1
bit 2
bit 7
bit 0
TX/CK Pin
(SCKP = 0)
bit 7
bit 1
Word 1
Word 2
TX/CK Pin
(SCKP = 1)
Write to
TXREG Reg
Write Word 1
Write Word 2
TXIF bit
(Interrupt Flag)
TRMT bit
TXEN bit
Note:
‘1’
‘1’
Sync Master mode, SPBRGL = 0, continuous transmission of two 8-bit words.
FIGURE 21-11:
SYNCHRONOUS TRANSMISSION (THROUGH TXEN)
RX/DT Pin
bit 0
bit 1
bit 2
bit 6
bit 7
TX/CK Pin
Write to
TXREG Reg.
TXIF bit
TRMT bit
TXEN bit
TABLE 21-7:
Name
BAUDCON
INTCON
PIE1
PIR1
RCSTA
SUMMARY OF REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER
TRANSMISSION
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Register
on Page
ABDOVF
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
186
GIE
PEIE
TMR0IE
INTE
IOCIE
TMR0IF
INTF
IOCIF
74
TMR1GIE
ADIE
RCIE(1)
TXIE(1)
—
—
TMR2IE
TMR1IE
75
TMR1GIF
ADIF
(1)
RCIF
TXIF
(1)
—
—
TMR2IF
TMR1IF
78
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
185
SPBRGL
BRG<7:0>
187*
SPBRGH
BRG<15:8>
187*
EUSART Transmit Data Register
TXREG
TXSTA
CSRC
TX9
TXEN
SYNC
SENDB
BRGH
177*
TRMT
TX9D
184
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used for synchronous master transmission.
* Page provides register information.
Note 1: PIC12(L)F1572 only.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 197
PIC12(L)F1571/2
21.5.1.5
Synchronous Master Reception
Data is received at the RX/DT pin. The RX/DT pin
output driver is automatically disabled when the
EUSART is configured for synchronous master receive
operation.
In Synchronous mode, reception is enabled by setting
either the Single Receive Enable bit (SREN of the
RCSTA register) or the Continuous Receive Enable bit
(CREN of the RCSTA register).
When SREN is set and CREN is clear, only as many
clock cycles are generated as there are data bits in a
single character. The SREN bit is automatically cleared
at the completion of one character. When CREN is set,
clocks are continuously generated until CREN is
cleared. If CREN is cleared in the middle of a character,
the CK clock stops immediately and the partial character is discarded. If SREN and CREN are both set, then
SREN is cleared at the completion of the first character
and CREN takes precedence.
To initiate reception, set either SREN or CREN. Data is
sampled at the RX/DT pin on the trailing edge of the
TX/CK clock pin and is shifted into the Receive Shift
Register (RSR). When a complete character is
received into the RSR, the RCIF bit is set and the character is automatically transferred to the two-character
receive FIFO. The Least Significant eight bits of the top
character in the receive FIFO are available in RCREG.
The RCIF bit remains set as long as there are unread
characters in the receive FIFO.
Note:
21.5.1.6
If the RX/DT function is on an analog pin,
the corresponding ANSELx bit must be
cleared for the receiver to function.
Slave Clock
Synchronous data transfers use a separate clock line,
which is synchronous with the data. A device configured
as a slave receives the clock on the TX/CK line. The
TX/CK pin output driver is automatically disabled when
the device is configured for synchronous slave transmit
or receive operation. Serial data bits change on the
leading edge to ensure they are valid at the trailing edge
of each clock. One data bit is transferred for each clock
cycle. Only as many clock cycles should be received as
there are data bits.
Note:
If the device is configured as a slave and
the TX/CK function is on an analog pin, the
corresponding ANSELx bit must be
cleared.
DS40001723D-page 198
21.5.1.7
Receive Overrun Error
The receive FIFO buffer can hold two characters. An
overrun error will be generated if a third character, in its
entirety, is received before RCREG is read to access
the FIFO. When this happens, the OERR bit of the
RCSTA register is set. Previous data in the FIFO will
not be overwritten. The two characters in the FIFO
buffer can be read, however, no additional characters
will be received until the error is cleared. The OERR bit
can only be cleared by clearing the overrun condition.
If the overrun error occurred when the SREN bit is set
and CREN is clear, then the error is cleared by reading
RCREG. If the overrun occurred when the CREN bit is
set, then the error condition is cleared by either clearing
the CREN bit of the RCSTA register or by clearing the
SPEN bit which resets the EUSART.
21.5.1.8
Receiving 9-Bit Characters
The EUSART supports 9-bit character reception. When
the RX9 bit of the RCSTA register is set the EUSART
will shift 9 bits into the RSR for each character
received. The RX9D bit of the RCSTA register is the
ninth, and Most Significant, data bit of the top unread
character in the receive FIFO. When reading 9-bit data
from the receive FIFO buffer, the RX9D data bit must
be read before reading the eight Least Significant bits
from the RCREG.
21.5.1.9
Synchronous Master Reception Setup
1.
Initialize the SPBRGH/SPBRGL register pair for
the appropriate baud rate. Set or clear the
BRGH and BRG16 bits, as required, to achieve
the desired baud rate.
2. Clear the ANSELx bit for the RX pin (if applicable).
3. Enable the synchronous master serial port by
setting bits, SYNC, SPEN and CSRC.
4. Ensure bits, CREN and SREN, are clear.
5. If interrupts are desired, set the RCIE bit of the
PIE1 register, and the GIE and PEIE bits of the
INTCON register.
6. If 9-bit reception is desired, set bit, RX9.
7. Start reception by setting the SREN bit or for
continuous reception, set the CREN bit.
8. Interrupt flag bit, RCIF, will be set when reception of a character is complete. An interrupt will
be generated if the enable bit, RCIE, was set.
9. Read the RCSTA register to get the ninth bit (if
enabled) and determine if any error occurred
during reception.
10. Read the 8-bit received data by reading the
RCREG register.
11. If an overrun error occurs, clear the error by either
clearing the CREN bit of the RCSTA register or by
clearing the SPEN bit which resets the EUSART.
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
FIGURE 21-12:
SYNCHRONOUS RECEPTION (MASTER MODE, SREN)
RX/DT
Pin
bit 0
bit 1
bit 2
bit 3
bit 4
bit 5
bit 6
bit 7
TX/CK Pin
(SCKP = 0)
TX/CK Pin
(SCKP = 1)
Write to
SREN bit
SREN bit
CREN bit ‘0’
‘0’
RCIF bit
(Interrupt)
Read
RCREG
Note:
Timing diagram demonstrates Sync Master mode with bit SREN = 1 and bit BRGH = 0.
TABLE 21-8:
Name
BAUDCON
INTCON
PIE1
PIR1
SUMMARY OF REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER
RECEPTION
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Register
on Page
ABDOVF
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
186
GIE
PEIE
TMR0IE
INTE
IOCIE
TMR0IF
INTF
IOCIF
74
TMR1GIE
ADIE
RCIE(1)
TXIE(1)
—
—
TMR2IE
TMR1IE
75
ADIF
RCIF(1)
TXIF(1)
—
—
TMR2IF
TMR1IF
TMR1GIF
RCREG
RCSTA
EUSART Receive Data Register
SPEN
RX9
SREN
SPBRGL
ADDEN
FERR
OERR
RX9D
BRG<7:0>
SPBRGH
TXSTA
CREN
TX9
TXEN
SYNC
SENDB
185
187*
BRG<15:8>
CSRC
78
180*
187*
BRGH
TRMT
TX9D
184
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used for synchronous master reception.
* Page provides register information.
Note 1: PIC12(L)F1572 only.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 199
PIC12(L)F1571/2
21.5.2
SYNCHRONOUS SLAVE MODE
If two words are written to the TXREG and then the
SLEEP instruction is executed, the following will occur:
The following bits are used to configure the EUSART
for synchronous slave operation:
•
•
•
•
•
1.
SYNC = 1
CSRC = 0
SREN = 0 (for transmit); SREN = 1 (for receive)
CREN = 0 (for transmit); CREN = 1 (for receive)
SPEN = 1
2.
3.
4.
Setting the SYNC bit of the TXSTA register configures the
device for synchronous operation. Clearing the CSRC bit
of the TXSTA register configures the device as a slave.
Clearing the SREN and CREN bits of the RCSTA register
ensures that the device is in Transmit mode; otherwise,
the device will be configured to receive. Setting the SPEN
bit of the RCSTA register enables the EUSART.
21.5.2.1
5.
21.5.2.2
EUSART Synchronous Slave
Transmit
1.
The operation of the Synchronous Master and
Slave modes is identical (see Section 21.5.1.3
“Synchronous Master Transmission”), except in the
case of Sleep mode.
2.
3.
4.
5.
6.
7.
8.
TABLE 21-9:
Name
BAUDCON
INTCON
PIE1
PIR1
RCSTA
Synchronous Slave Transmission
Setup
Set the SYNC and SPEN bits, and clear the
CSRC bit.
Clear the ANSELx bit for the CK pin (if applicable).
Clear the CREN and SREN bits.
If interrupts are desired, set the TXIE bit of the
PIE1 register and the GIE and PEIE bits of the
INTCON register.
If 9-bit transmission is desired, set the TX9 bit.
Enable transmission by setting the TXEN bit.
If 9-bit transmission is selected, insert the Most
Significant bit into the TX9D bit.
Start transmission by writing the Least
Significant eight bits to the TXREG register.
SUMMARY OF REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE
TRANSMISSION
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Register
on Page
ABDOVF
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
186
GIE
PEIE
TMR0IE
INTE
IOCIE
TMR0IF
INTF
IOCIF
74
TMR1GIE
ADIE
RCIE(1)
TXIE(1)
—
—
TMR2IE
TMR1IE
75
TMR1GIF
ADIF
(1)
RCIF
TXIF
(1)
—
—
TMR2IF
TMR1IF
78
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
185
CSRC
TX9
TXEN
TRMT
TX9D
TXREG
TXSTA
The first character will immediately transfer to
the TSR register and transmit.
The second word will remain in the TXREG
register.
The TXIF bit will not be set.
After the first character has been shifted out of
TSR, the TXREG register will transfer the
second character to the TSR and the TXIF bit
will now be set.
If the PEIE and TXIE bits are set, the interrupt
will wake the device from Sleep and execute the
next instruction. If the GIE bit is also set, the
program will call the Interrupt Service Routine.
EUSART Transmit Data Register
SYNC
SENDB
BRGH
177*
184
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used for synchronous slave transmission.
* Page provides register information.
Note 1: PIC12(L)F1572 only.
DS40001723D-page 200
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
21.5.2.3
EUSART Synchronous Slave
Reception
21.5.2.4
1.
The operation of the Synchronous Master and Slave
modes is identical (Section 21.5.1.5 “Synchronous
Master Reception”), with the following exceptions:
2.
3.
• Sleep
• CREN bit is always set, therefore, the receiver is
never Idle
• SREN bit, which is a “don’t care” in Slave mode
A character may be received while in Sleep mode by
setting the CREN bit prior to entering Sleep. Once the
word is received, the RSR register will transfer the data
to the RCREG register. If the RCIE enable bit is set, the
interrupt generated will wake the device from Sleep
and execute the next instruction. If the GIE bit is also
set, the program will branch to the interrupt vector.
4.
5.
6.
7.
8.
9.
Synchronous Slave Reception Setup
Set the SYNC and SPEN bits, and clear the
CSRC bit.
Clear the ANSELx bit for both the CK and DT
pins (if applicable).
If interrupts are desired, set the RCIE bit of the
PIE1 register, and the GIE and PEIE bits of the
INTCON register.
If 9-bit reception is desired, set the RX9 bit.
Set the CREN bit to enable reception.
The RCIF bit will be set when reception is
complete. An interrupt will be generated if the
RCIE bit was set.
If 9-bit mode is enabled, retrieve the Most
Significant bit from the RX9D bit of the RCSTA
register.
Retrieve the eight Least Significant bits from the
receive FIFO by reading the RCREG register.
If an overrun error occurs, clear the error by
either clearing the CREN bit of the RCSTA
register or by clearing the SPEN bit which resets
the EUSART.
TABLE 21-10: SUMMARY OF REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE
RECEPTION
Name
BAUDCON
INTCON
Bit 7
Bit 6
ABDOVF
GIE
Bit 2
Bit 1
Bit 0
Register
on Page
BRG16
—
WUE
ABDEN
186
IOCIE
TMR0IF
INTF
IOCIF
74
TXIE(1)
—
—
TMR2IE
TMR1IE
75
TXIF(1)
—
—
TMR2IF
TMR1IF
78
Bit 5
Bit 4
Bit 3
RCIDL
—
SCKP
PEIE
TMR0IE
INTE
PIE1
TMR1GIE
ADIE
RCIE(1)
PIR1
TMR1GIF
ADIF
RCIF(1)
RCSTA
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
185
TXSTA
CSRC
TX9
TXEN
SYNC
SENDB
BRGH
TRMT
TX9D
184
RCREG
EUSART Receive Data Register
180*
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used for synchronous slave reception.
* Page provides register information.
Note 1: PIC12(L)F1572 only.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 201
PIC12(L)F1571/2
NOTES:
DS40001723D-page 202
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
22.0
16-BIT PULSE-WIDTH
MODULATION (PWM) MODULE
Each PWM module has four Offset modes:
•
•
•
•
The Pulse-Width Modulation (PWM) module generates
a pulse-width modulated signal determined by the
phase, duty cycle, period and offset event counts that
are contained in the following registers:
•
•
•
•
Using the Offset modes, each PWM module can offset
its waveform relative to any other PWM module in the
same device. For a more detailed description of the
Offset modes, refer to Section 22.3 “Offset Modes”.
PWMxPH register
PWMxDC register
PWMxPR register
PWMxOF register
Every PWM module has a configurable reload
operation to ensure all event count buffers change at
the end of a period, thereby avoiding signal glitches.
Figure 22-2 shows a simplified block diagram of the
reload operation. For a more detailed description of
the reload operation, refer to Section 22.4 “Reload
Operation”.
Figure 22-1 shows a simplified block diagram of the
PWM operation.
Each PWM module has four modes of operation:
•
•
•
•
Independent Run
Slave Run with Synchronous Start
One-Shot Slave with Synchronous Start
Continuous Run Slave with Synchronous Start
and Timer Reset
Standard
Set On Match
Toggle On Match
Center-Aligned
For a more detailed description of each PWM mode,
refer to Section 22.2 “PWM Modes”.
FIGURE 22-1:
16-BIT PWM BLOCK DIAGRAM
MODE<1:0>
EN
PHx_match
PWM Control
Unit
DCx_match
OF3_match(1)
11
OF2_match(1)
10
(1)
OF1_match
Reserved
Rev. 10-000152A
4/21/2014
D
Q4
PWMxOUT
Q
CK
PWMxPOL
PWMx_output
OF_match
01
Offset
Control
PRx_match
To Peripherals
PWMxOE
00
PWMx
OFM<1:0>
E
OFS
Comparator
PWM_clock
PRx_match
set PRIF
16-bt Latch LDx_trigger
PWMxPR
Comparator
Note 1:
PHx_match
set PHIF
16-bt Latch LDx_trigger
PWMxPH
R
U/D
PWMxTMR
TRIS Control
Comparator
OFx_match
set OFIF
16-bt Latch LDx_trigger
PWMxOF
Comparator
DCx_match
set DCIF
16-bt Latch LDx_trigger
PWMxDC
A PWM module cannot trigger from its own offset match event.
The input corresponding to a PWM module’s own offset match is reserved.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 203
PIC12(L)F1571/2
FIGURE 22-2:
LOAD TRIGGER BLOCK DIAGRAM
Rev. 10-000153A
4/21/2014
LD3_trigger(1)
11
(1)
10
LD1_trigger(1)
01
Reserved
00
LD2_trigger
1
0
PWMxLDS
LDx_trigger
22.1
PWM_clock
1. The input corresponding to a PWM module’s own load trigger is reserved.
2. PWMxLDA is cleared by hardware upon LDx_trigger.
Fundamental Operation
FIGURE 22-3:
The PWM module produces a 16-bit resolution
pulse-width modulated output.
Each PWM module has an independent timer driven by
a selection of clock sources determined by the
PWMxCLKCON register (Register 22-4). The timer
value is compared to event count registers to generate
the various events of a the PWM waveform, such as the
period and duty cycle. For a block diagram describing
the clock sources, refer to Figure 22-3.
The current state of the PWM output can be read using
the OUT bit of the PWMxCON register. In some modes,
this bit can be set and cleared by software, giving
additional software control over the PWM waveform.
This bit is synchronized to FOSC/4 and therefore, does
not change in real time with respect to the PWM_clock.
If PWM_clock > FOSC/4, the OUT bit may
not accurately represent the output state of
the PWM.
PWM CLOCK SOURCE
BLOCK DIAGRAM
Rev. 10-000156A
1/7/2015
PWMxCS<1:0>
Each PWM module can be enabled individually using
the EN bit of the PWMxCON register, or several PWM
modules can be enabled simultaneously using the
mirror bits of the PWMEN register.
Note:
Q
PRx_match
PWMxLDT
Note
D
PWMxLDA(2)
22.1.1
FOSC
00
HFINTOSC
01
LFINTOSC
10
Reserved
11
PWMxPS<2:0>
Prescaler
PWMx_clock
PWMx PIN CONFIGURATION
All PWM outputs are multiplexed with the PORT data
latch, so the pins must also be configured as outputs by
clearing the associated PORT TRISx bits.
The slew rate feature may be configured to optimize
the rate to be used in conjunction with the PWM
outputs. High-speed output switching is attained by
clearing the associated PORT SLRCONx bits.
The PWM outputs can be configured to be open-drain
outputs by setting the associated PORT ODCONx bits.
22.1.2
PWMx Output Polarity
The output polarity is inverted by setting the POL bit of
the PWMxCON register. The polarity control affects the
PWM output even when the module is not enabled.
DS40001723D-page 204
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
22.2
PWM Modes
PWM modes are selected with the MODE<1:0> bits of
the PWMxCON register (Register 22-1).
In all PWM modes, an offset match event can also be
used to synchronize the PWMxTMR in three Offset
modes. See Section 22.3 “Offset Modes” for more
information.
22.2.1
STANDARD MODE
The Standard mode (MODE<1:0> = 00) selects a
single-phase PWM output. The PWM output in this
mode is determined by when the period, duty cycle and
phase counts match the PWMxTMR value. The start of
the duty cycle occurs on the phase match and the end
of the duty cycle occurs on the duty cycle match. The
period match resets the timer. The offset match can
also be used to synchronize the PWMxTMR in the
Offset modes. See Section 22.3 “Offset Modes” for
more information.
Equation 22-1 is used to calculate the PWM period in
Standard mode.
Equation 22-2 is used to calculate the PWM duty cycle
ratio in Standard mode.
EQUATION 22-1:
PWM PERIOD IN
STANDARD MODE
 PWMxPR + 1   Prescale
Period = -------------------------------------------------------------------PWMxCLK
EQUATION 22-2:
PWM DUTY CYCLE IN
STANDARD MODE
 PWMxDC – PWMx PH 
Duty Cycle = -----------------------------------------------------------------
PWMxPR + 1
A detailed timing diagram for Standard mode is shown
in Figure 22-4.
22.2.2
SET ON MATCH MODE
The Set On Match mode (MODE<1:0> = 01) generates
an active output when the phase count matches the
PWMxTMR value. The output stays active until the
OUT bit of the PWMxCON register is cleared or the
PWM module is disabled. The duty cycle count has no
effect in this mode. The period count only determines
the maximum PWMxTMR value above which no phase
matches can occur.
The OUT bit can be used to set or clear the output of
the PWM in this mode. Writes to this bit will take place
on the next rising edge of the PWM_clock after the bit
is written.
A detailed timing diagram for Set On Match mode is
shown in Figure 22-5.
22.2.3
TOGGLE ON MATCH MODE
The Toggle On Match mode (MODE<1:0> = 10) generates a 50% duty cycle PWM with a period twice as long
as that computed for the Standard PWM mode. Duty
cycle count has no effect in this mode. The phase count
determines how many PWMxTMR periods, after a
period event, the output will toggle.
Writes to the OUT bit of the PWMxCON register will
have no effect in this mode.
A detailed timing diagram for Toggle On Match mode is
shown in Figure 22-6.
22.2.4
CENTER-ALIGNED MODE
The Center-Aligned mode (MODE = 11) generates a
PWM waveform that is centered in the period. In this
mode, the period is two times the PWMxPR count. The
PWMxTMR counts up to the period value, then counts
back down to 0. The duty cycle count determines both
the start and end of the active PWM output. The start of
the duty cycle occurs at the match event when
PWMxTMR is incrementing and the duty cycle ends at
the match event when PWMxTMR is decrementing.
The incrementing match value is the period count
minus the duty cycle count. The decrementing match
value is the incrementing match value plus 1.
Equation 22-3 is used to calculate the PWM period in
Center-Aligned mode.
EQUATION 22-3:
PWM PERIOD IN
CENTER-ALIGNED MODE
 PWMxPR + 1   Prescale  2
Period = --------------------------------------------------------------------------PWMxCLK
Equation 22-4 is used to calculate the PWM duty cycle
ratio in Center-Aligned mode.
EQUATION 22-4:
PWM DUTY CYCLE IN
CENTER-ALIGNED MODE
PWMxDC  2
Duty Cycle = ------------------------------------------------ PWMx PR + 1   2
Writes to the OUT bit will have no effect in this mode.
A detailed timing diagram for Center-Aligned mode is
shown in Figure 22-7.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 205
STANDARD PWM MODE TIMING DIAGRAM
Rev. 10-000142A
9/5/2013
Period
Duty Cycle
Phase
PWMxCLK
PWMxPR
10
PWMxPH
4
PWMxDC
9
PWMxTMR
0
1
2
3
4
5
6
7
8
9
10
0
1
2
3
4
5
6
PWMxOUT
FIGURE 22-5:
SET ON MATCH PWM MODE TIMING DIAGRAM
Rev. 10-000143A
9/5/2013
Period
Phase
 2013-2015 Microchip Technology Inc.
PWMxCLK
PWMxPR
10
PWMxPH
4
PWMxTMR
PWMxOUT
0
1
2
3
4
5
6
7
8
9
10
0
1
2
3
4
5
6
PIC12(L)F1571/2
DS40001723D-page 206
FIGURE 22-4:
 2013-2015 Microchip Technology Inc.
FIGURE 22-6:
TOGGLE ON MATCH PWM MODE TIMING DIAGRAM
Rev. 10-000144A
9/5/2013
Period
Phase
PWMxCLK
PWMxPR
10
PWMxPH
4
PWMxTMR
0
1
2
3
4
5
6
7
8
9
10
0
1
2
3
4
5
6
PWMxOUT
FIGURE 22-7:
CENTER-ALIGNED PWM MODE TIMING DIAGRAM
Rev. 10-000 145A
Rev. 4/22/201
10-000 145A
4
4/22/201 4
Period
Period
PWMxPR
PWMxPR
66
PWMxDC
PWMxDC
44
DS40001723D-page 207
PWMxTMR
PWMxTMR
PWMxOUT
PWMxOUT
00
11
22
33
44
55
66
66
55
44
33
22
11
00
00
11
22
33
PIC12(L)F1571/2
Duty
DutyCycle
Cycle
PWMxCLK
PWMxCLK
PIC12(L)F1571/2
22.3
Offset Modes
The Offset modes provide the means to adjust the waveform of a slave PWM module relative to the waveform of
a master PWM module in the same device.
22.3.1
INDEPENDENT RUN MODE
In Independent Run mode (OFM<1:0> = 00), the PWM
module is unaffected by the other PWM modules in the
device. The PWMxTMR associated with the PWM
module in this mode starts counting as soon as the EN bit
associated with this PWM module is set and continues
counting until the EN bit is cleared. Period events reset
the PWMxTMR to zero, after which, the timer continues to
count.
A detailed timing diagram of this mode used with
Standard PWM mode is shown in Figure 22-8.
22.3.2
SLAVE RUN MODE WITH SYNC START
In Slave Run mode with Sync Start (OFM<1:0> = 01),
the slave PWMxTMR waits for the master’s OFx_match
event. When this event occurs, if the EN bit is set, the
PWMxTMR begins counting and continues to count
until software clears the EN bit. Slave period events
reset the PWMxTMR to zero, after which, the timer
continues to count.
A detailed timing diagram of this mode used with
Standard PWM mode is shown in Figure 22-9.
22.3.3
ONE-SHOT SLAVE MODE WITH
SYNC START
In One-Shot Slave mode with Synchronous Start
(OFM<1:0> = 10), the slave PWMxTMR waits until the
master's OFx_match event. The timer then begins counting, starting from the value that is already in the timer, and
continues to count until the period match event. When the
period event occurs, the timer resets to zero and stops
counting. The timer then waits until the next master
OFx_match event, after which, it begins counting again to
repeat the cycle. An OFx_match event that occurs before
the slave PWM has completed the previously triggered
period will be ignored. A slave period that is greater than
the master period, but less than twice the master period,
will result in a slave output every other master period.
Note:
During the time the slave timers are
resetting to zero, if another offset match
event is received, it is possible that the slave
PWM would not recognize this match event
and the slave timers would fail to begin
counting again. This would result in missing
duty cycles from the output of the slave
PWM. To prevent this from happening,
avoid using the same period for both the
master and slave PWMs.
22.3.4
CONTINUOUS RUN SLAVE MODE
WITH SYNC START AND TIMER
RESET
In Continuous Run Slave mode with Synchronous
Start and Timer Reset (OFM<1:0> = 11), the slave
PWMxTMR is inhibited from counting after the slave
PWM enable is set. The first master OFx_match event
starts the slave PWMxTMR. Subsequent master
OFx_match events reset the slave PWMxTMR timer
value back to 1, after which, the slave PWMxTMR continues to count. The next master OFx_match event
resets the slave PWMxTMR back to 1 to repeat the
cycle. Slave period events that occur before the
master’s OFx_match event will reset the slave
PWMxTMR to zero, after which, the timer will continue
to count. Slaves operating in this mode must have a
PWMxPH register pair value equal to or greater than 1;
otherwise, the phase match event will not occur
precluding the start of the PWM output duty cycle.
The offset timing will persist If both the master and
slave PWMxPR values are the same, and the Slave
Offset mode is changed to Independent Run mode
while the PWM module is operating.
A detailed timing diagram of this mode used in
Standard PWM mode is shown in Figure 22-11.
Note:
22.3.5
Unexpected results will occur if the slave
PWM_clock is a higher frequency than the
master PWM_clock.
OFFSET MATCH IN
CENTER-ALIGNED MODE
When a master is operating in Center-Aligned mode,
the offset match event depends on which direction the
PWMxTMR is counting. Clearing the OFO bit of the
PWMxOFCON register will cause the OFx_match
event to occur when the timer is counting up. Setting
the OFO bit of the PWMxOFCON register will cause
the OFx_match event to occur when the timer is
counting down. The OFO bit is ignored in
non-Center-Aligned modes.
The OFO bit is double-buffered and requires setting the
LDA bit to take effect when the PWM module is
operating.
Detailed timing diagrams of Center-Aligned mode
using offset match control in Independent Slave with
Sync Start mode can be seen in Figure 22-12 and
Figure 22-13.
A detailed timing diagram of this mode used with
Standard PWM mode is shown in Figure 22-10.
DS40001723D-page 208
 2013-2015 Microchip Technology Inc.
 2013-2015 Microchip Technology Inc.
FIGURE 22-8:
INDEPENDENT RUN MODE TIMING DIAGRAM
Rev. 10-000 146B
7/8/201 5
Period
Duty Cycle
Phase
Offset
PWMxCLK
PWMxPR
10
PWMxPH
3
PWMxDC
5
PWMxOF
2
PWMxTMR
0
1
2
3
4
5
6
7
8
9
10
0
1
2
3
4
5
6
0
1
2
3
4
0
1
2
3
4
0
1
2
3
4
0
1
2
PWMxOUT
OFx_match
PHx_match
DCx_match
PRx_match
DS40001723D-page 209
PWMyPR
4
PWMyPH
0
PWMyDC
1
PWMyOUT
Note: PWMx = Master, PWMy = Slave
PIC12(L)F1571/2
PWMyTMR
SLAVE RUN MODE WITH SYNC START TIMING DIAGRAM
Rev. 10-000 147B
7/8/201 5
Period
Duty Cycle
Phase
Offset
PWMxCLK
PWMxPR
10
PWMxPH
3
PWMxDC
5
PWMxOF
2
PWMxTMR
0
1
2
3
4
5
6
7
8
9
10
0
1
2
3
4
5
6
1
2
3
4
0
1
2
3
4
0
1
2
3
4
0
PWMxOUT
OFx_match
PWMyTMR
0
PWMyPR
4
PWMyPH
0
PWMyDC
1
 2013-2015 Microchip Technology Inc.
PWMyOUT
Note: Master = PWMx, Slave = PWMy
PIC12(L)F1571/2
DS40001723D-page 210
FIGURE 22-9:
 2013-2015 Microchip Technology Inc.
FIGURE 22-10:
ONE-SHOT SLAVE RUN MODE WITH SYNC START TIMING DIAGRAM
Rev. 10-000 148B
7/8/201 5
Period
Duty Cycle
Phase
Offset
PWMxCLK
PWMxPR
10
PWMxPH
3
PWMxDC
5
PWMxOF
2
PWMxTMR
0
1
2
3
4
5
6
1
2
3
4
7
8
9
10
0
1
2
3
4
5
6
1
2
3
4
PWMxOUT
OFx_match
PWMyTMR
0
0
4
PWMyPH
0
PWMyDC
1
PWMyOUT
Note: Master = PWMx, Slave = PWMy
DS40001723D-page 211
PIC12(L)F1571/2
PWMyPR
CONTINUOUS SLAVE RUN MODE WITH IMMEDIATE RESET AND SYNC START TIMING DIAGRAM
Rev. 10-000 149B
7/8/201 5
Period
Duty Cycle
Phase
Offset
PWMxCLK
PWMxPR
10
PWMxPH
3
PWMxDC
5
PWMxOF
2
PWMxTMR
0
1
2
3
4
5
6
7
8
9
10
0
1
2
3
4
5
6
1
2
3
4
0
1
2
3
4
0
1
1
2
3
4
PWMxOUT
OFx_match
PWMyTMR
0
PWMyPR
4
PWMyPH
1
PWMyDC
2
 2013-2015 Microchip Technology Inc.
PWMyOUT
Note: Master= PWMx, Slave=PWMy
PIC12(L)F1571/2
DS40001723D-page 212
FIGURE 22-11:
 2013-2015 Microchip Technology Inc.
FIGURE 22-12:
OFFSET MATCH ON INCREMENTING TIMER TIMING DIAGRAM
Rev. 10-000 150B
7/9/201 5
Period
Duty Cycle
Offset
PWMxCLK
PWMxPR
6
PWMxDC
2
PWMxOF
2
PWMxTMR
0
1
2
3
4
5
6
6
5
4
3
2
0
1
2
3
4
4
3
2
1
0
1
0
0
1
2
3
0
1
PWMxOUT
OFx_match
PHx_match
DCx_match
PRx_match
PWMyTMR
0
4
PWMyDC
1
PWMyOUT
Note: Master = PWMx, Slave = PWMy
DS40001723D-page 213
PIC12(L)F1571/2
PWMyPR
0
OFFSET MATCH ON DECREMENTING TIMER TIMING DIAGRAM
Rev. 10-000 151B
7/9/201 5
Period
Duty Cycle
Offset
PWMxCLK
PWMxPR
6
PWMxDC
2
PWMxOF
2
PWMxTMR
0
1
2
3
4
5
6
6
5
4
3
2
1
0
0
1
2
3
0
1
2
3
4
4
3
PWMxOUT
OF5_match
PH5_match
DC5_match
PR5_match
PWMyTMR
0
 2013-2015 Microchip Technology Inc.
PWMyPR
4
PWMyDC
1
PWMyOUT
Note: Master = PWMx, Slave = PWMy
PIC12(L)F1571/2
DS40001723D-page 214
FIGURE 22-13:
PIC12(L)F1571/2
22.4
Reload Operation
Four of the PWM module control register pairs and one
control bit are double-buffered so that all can be
updated simultaneously. These include:
•
•
•
•
•
PWMxPHH:PWMxPHL register pair
PWMxDCH:PWMxDCL register pair
PWMxPRH:PWMxPRL register pair
PWMxOFH:PWMxOFL register pair
OFO control bit
When written to, these registers do not immediately
affect the operation of the PWM. By default, writes to
these registers will not be loaded into the PWM Operating Buffer registers until after the arming conditions
are met. The arming control has two methods of
operation:
22.4.2
When the LDT bit is set, then the Triggered mode is
selected and a trigger event is required for the LDA bit
to take effect. The trigger source is the buffer load
event of one of the other PWM modules in the device.
The triggering source is selected by the LDS<1:0> bits
of the PWMxLDCON register. The buffers will be
loaded at the first period event following the trigger
event. Triggered reloading is used when a PWM
module is operating as a slave to another PWM and it
is necessary to synchronize the buffer reloads in both
modules.
Note 1: The buffer load operation clears the
LDA bit.
2: If the LDA bit is set at the same time as
PWMxTMR = PWMxPR, the LDA bit is
ignored until the next period event. Such
is the case when triggered reload is
selected and the triggering event occurs
simultaneously with the target’s period
event.
• Immediate
• Triggered
The LDT bit of the PWMxLDCON register controls the
arming method. Both methods require the LDA bit to be
set. All four buffer pairs will load simultaneously at the
loading event.
22.4.1
IMMEDIATE RELOAD
When the LDT bit is clear, then the immediate mode is
selected and the buffers will be loaded at the first period
event after the LDA bit is set. Immediate reloading is
used when a PWM module is operating stand-alone or
when the PWM module is operating as a master to
other slave PWM modules.
 2013-2015 Microchip Technology Inc.
TRIGGERED RELOAD
22.5
Operation in Sleep Mode
Each PWM module will continue to operate in Sleep
mode when either the HFINTOSC or LFINTOSC is
selected as the clock source by PWMxCLKCON<1:0>.
22.6
Interrupts
Each PWM module has four independent interrupts
based on the phase, duty cycle, period and offset match
events. The interrupt flag is set on the rising edge of
each of these signals. Refer to Figures 22-12 and 22-13
for detailed timing diagrams of the match signals.
DS40001723D-page 215
PIC12(L)F1571/2
22.7
Register Definitions: PWM Control
TABLE 22-1:
Long bit name prefixes for the 16-bit PWM peripherals
are shown in Table 22-1. Refer to Section
1.1 “Register and Bit Naming Conventions” for more
information
REGISTER 22-1:
BIT NAME PREFIXES
Peripheral
Bit Name Prefix
PWM1
PWM1
PWM2
PWM2
PWM3
PWM3
PWMxCON: PWMx CONTROL REGISTER
R/W-0/0
R/W-0/0
R/HS/HC-0/0
R/W-0/0
EN
OE
OUT
POL
R/W-0/0
R/W-0/0
MODE<1:0>
U-0
U-0
—
—
bit 7
bit 0
Legend:
HC = Hardware Clearable bit
HS = Hardware Settable bit
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
EN: PWMx Module Enable bit
1 = Module is enabled
0 = Module is disabled
bit 6
OE: PWMx Output Enable bit
1 = PWM output pin is enabled
0 = PWM output pin is disabled
bit 5
OUT: Output State of the PWMx Module bit
bit 4
POL: PWMx Output Polarity Control bit
1 = PWM output active state is low
0 = PWM output active state is high
bit 3-2
MODE<1:0>: PWMx Mode Control bits
11 = Center-Aligned mode
10 = Toggle On Match mode
01 = Set On Match mode
00 = Standard PWM mode
bit 1-0
Unimplemented: Read as ‘0’
DS40001723D-page 216
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
REGISTER 22-2:
PWMxINTE: PWMx INTERRUPT ENABLE REGISTER
U-0
U-0
U-0
U-0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
—
—
—
—
OFIE
PHIE
DCIE
PRIE
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-4
Unimplemented: Read as ‘0’
bit 3
OFIE: Offset Interrupt Enable bit
1 = Interrupts CPU on offset match
0 = Does not interrupt CPU on offset match
bit 2
PHIE: Phase Interrupt Enable bit
1 = Interrupts CPU on phase match
0 = Does not Interrupt CPU on phase match
bit 1
DCIE: Duty Cycle Interrupt Enable bit
1 = Interrupts CPU on duty cycle match
0 = Does not interrupt CPU on duty cycle match
bit 0
PRIE: Period Interrupt Enable bit
1 = Interrupts CPU on period match
0 = Does not interrupt CPU on period match
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REGISTER 22-3:
PWMxINTF: PWMx INTERRUPT REQUEST REGISTER
U-0
U-0
U-0
U-0
R/W/HS-0/0
R/W/HS-0/0
—
—
—
—
OFIF
PHIF
R/W/HS-0/0 R/W/HS-0/0
DCIF
bit 7
PRIF
bit 0
Legend:
HC = Hardware Clearable bit
HS = Hardware Settable bit
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-4
Unimplemented: Read as ‘0’
bit 3
OFIF: Offset Interrupt Flag bit(1)
1 = Offset match event occurred
0 = Offset match event did not occur
bit 2
PHIF: Phase Interrupt Flag bit(1)
1 = Phase match event occurred
0 = Phase match event did not occur
bit 1
DCIF: Duty Cycle Interrupt Flag bit(1)
1 = Duty cycle match event occurred
0 = Duty cycle match event did not occur
bit 0
PRIF: Period Interrupt Flag bit(1)
1 = Period match event occurred
0 = Period match event did not occur
Note 1:
Bit is forced clear by hardware while module is disabled (EN = 0).
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REGISTER 22-4:
U-0
PWMxCLKCON: PWMx CLOCK CONTROL REGISTER
R/W-0/0
—
R/W-0/0
R/W-0/0
PS<2:0>
U-0
U-0
—
—
R/W-0/0
bit 7
R/W-0/0
CS<1:0>
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
Unimplemented: Read as ‘0’
bit 6-4
PS<2:0>: Clock Source Prescaler Select bits
111 = Divides clock source by 128
110 = Divides clock source by 64
101 = Divides clock source by 32
100 = Divides clock source by 16
011 = Divides clock source by 8
010 = Divides clock source by 4
001 = Divides clock source by 2
000 = No prescaler
bit 3-2
Unimplemented: Read as ‘0’
bit 1-0
CS<1:0>: Clock Source Select bits
11 = Reserved
10 = LFINTOSC (continues to operate during Sleep)
01 = HFINTOSC (continues to operate during Sleep)
00 = FOSC
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REGISTER 22-5:
PWMxLDCON: PWMx RELOAD TRIGGER SOURCE SELECT REGISTER
R/W-0/0
R/W-0/0
U-0
U-0
U-0
U-0
LDA(1)
LDT
—
—
—
—
R/W-0/0
bit 7
R/W-0/0
LDS<1:0>
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
LDA: Load Buffer Armed bit(1)
If LDT = 1:
1 = Loads the OFx, PHx, DCx and PRx buffers at the end of the period when the selected trigger occurs
0 = Does not load buffers or load has completed
If LDT = 0:
1 = Loads the OFx, PHx, DCx and PRx buffers at the end of the current period
0 = Does not load buffers or load has completed
bit 6
LDT: Load Buffer on Trigger bit
1 = Loads buffers on trigger enabled
0 = Loads buffers on trigger disabled
Loads the OFx, PHx, DCx and PRx buffers at the end of every period after the selected trigger occurs.
Reloads internal double buffers at the end of current period. The LDS<1:0> bits are ignored.
bit 5-2
Unimplemented: Read as ‘0’
bit 1-0
LDS<1:0>: Load Trigger Source Select bits
11 = LD3_trigger(2)
10 = LD2_trigger(2)
01 = LD1_trigger(2)
00 = Reserved
Note 1:
2:
This bit is cleared by the module after a reload operation. It can be cleared in software to clear an existing
arming event.
The LD_trigger corresponding to the PWM used becomes reserved.
DS40001723D-page 220
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REGISTER 22-6:
U-0
PWMxOFCON: PWMx OFFSET TRIGGER SOURCE SELECT REGISTER
R/W-0/0
—
R/W-0/0
R/W-0/0
U-0
U-0
OFO(1)
—
—
OFM<1:0>
R/W-0/0
R/W-0/0
OFS<1:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
Unimplemented: Read as ‘0’
bit 6-5
OFM<1:0>: Offset Mode Select bits
11 = Continuous Slave Run mode with immediate Reset and synchronized start when the selected
offset trigger occurs
10 = One-Shot Slave Run mode with synchronized start when the selected offset trigger occurs
01 = Independent Slave Run mode with synchronized start when the selected offset trigger occurs
00 = Independent Run mode
bit 4
OFO: Offset Match Output Control bit(1)
If MODE<1:0> = 11 (PWM Center-Aligned mode):
1 = OFx_match occurs on counter match when counter decrementing, (second match)
0 = OFx_match occurs on counter match when counter incrementing, (first match)
If MODE<1:0> = 00, 01 or 10 (all other modes):
Bit is ignored.
bit 3-2
Unimplemented: Read as ‘0’
bit 1-0
OFS<1:0>: Offset Trigger Source Select bits
11 = OF3_match(1)
10 = OF2_match(1)
01 = OF1_match(1)
00 = Reserved
Note 1:
The OFx_match corresponding to the PWM used becomes reserved.
 2013-2015 Microchip Technology Inc.
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REGISTER 22-7:
R/W-x/u
PWMxPHH: PWMx PHASE COUNT HIGH REGISTER
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
PH<15:8>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-0
PH<15:8>: PWMx Phase High bits
Upper eight bits of PWM phase count.
REGISTER 22-8:
R/W-x/u
PWMxPHL: PWMx PHASE COUNT LOW REGISTER
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
PH<7:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-0
PH<7:0>: PWMx Phase Low bits
Lower eight bits of PWM phase count.
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REGISTER 22-9:
R/W-x/u
PWMxDCH: PWMx DUTY CYCLE COUNT HIGH REGISTER
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
DC<15:8>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-0
DC<15:8>: PWMx Duty Cycle High bits
Upper eight bits of PWM duty cycle count.
REGISTER 22-10: PWMxDCL: PWMx DUTY CYCLE COUNT LOW REGISTER
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
DC<7:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-0
DC<7:0>: PWMx Duty Cycle Low bits
Lower eight bits of PWM duty cycle count.
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REGISTER 22-11: PWMxPRH: PWMx PERIOD COUNT HIGH REGISTER
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
PR<15:8>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-0
PR<15:8>: PWMx Period High bits
Upper eight bits of PWM period count.
REGISTER 22-12: PWMxPRL: PWMx PERIOD COUNT LOW REGISTER
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
PR<7:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-0
PR<7:0>: PWMx Period Low bits
Lower eight bits of PWM period count.
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REGISTER 22-13: PWMxOFH: PWMx OFFSET COUNT HIGH REGISTER
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
OF<15:8>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-0
OF<15:8>: PWMx Offset High bits
Upper eight bits of PWM offset count.
REGISTER 22-14: PWMxOFL: PWMx OFFSET COUNT LOW REGISTER
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
OF<7:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-0
OF<7:0>: PWMx Offset Low bits
Lower eight bits of PWM offset count.
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REGISTER 22-15: PWMxTMRH: PWMx TIMER HIGH REGISTER
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
TMR<15:8>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-0
TMR<15:8>: PWMx Timer High bits
Upper eight bits of PWM timer counter.
REGISTER 22-16: PWMxTMRL: PWMx TIMER LOW REGISTER
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
TMR<7:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-0
TMR<7:0>: PWMx Timer Low bits
Lower eight bits of PWM timer counter.
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Note:
There are no long and short bit name variants for the following three mirror registers
REGISTER 22-17: PWMEN: PWMEN BIT ACCESS REGISTER
U-0
U-0
U-0
U-0
U-0
R/W-0/0
R/W-0/0
R/W-0/0
—
—
—
—
—
PWM3EN_A
PWM2EN_A
PWM1EN_A
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-3
Unimplemented: Read as ‘0’
bit 2-0
PWMxEN_A: PWM3/PWM2/PWM1 Enable bits
Mirror copy of EN bit (PWMxCON<7>).
REGISTER 22-18: PWMLD: LD BIT ACCESS REGISTER
U-0
U-0
U-0
U-0
U-0
R/W-0/0
—
—
—
—
—
PWM3LDA_A
R/W-0/0
R/W-0/0
PWM2LDA_A PWM1LDA_A
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-3
Unimplemented: Read as ‘0’
bit 2-0
PWMxLDA_A: PWM3/PWM2/PWM1 LD bits
Mirror copy of LD bit (PWMxLDCON<7>).
REGISTER 22-19: PWMOUT: PWMOUT BIT ACCESS REGISTER
U-0
U-0
U-0
U-0
U-0
—
—
—
—
—
R/W-0/0
R/W-0/0
R/W-0/0
PWM3OUT_A PWM2OUT_A PWM1OUT_A
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-3
Unimplemented: Read as ‘0’
bit 2-0
PWMxOUT_A: PWM3/PWM2/PWM1 Output bits
Mirror copy of OUT bit (PWMxCON<5>).
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TABLE 22-2:
Name
OSCCON
SUMMARY OF REGISTERS ASSOCIATED WITH PWM
Bit 7
Bit 6
Bit 5
SPLLEN
Bit 4
Bit 3
Bit 2
IRCF<3:0>
Bit 1
—
Bit 0
SCS<1:0>
Register
on Page
55
PIE3
—
PWM3IE
PWM2IE
PWM1IE
—
—
—
—
PIR3
—
PWM3IF
PWM2IF
PWM1IF
—
—
—
—
80
PWMEN
—
—
—
—
—
PWM3EN_A
PWM2EN_A
PWM1EN_A
227
PWMLD
—
—
—
—
—
PWM3LDA_A
PWM2LDA_A
PWM1LDA_A
227
PWMOUT
—
—
—
—
—
PWM3OUT_A PWM2OUT_A PWM1OUT_A
227
77
PWM1PHL
PH<7:0>
222
PWM1PHH
PH<15:8>
222
PWM1DCL
DC<7:0>
223
PWM1DCH
DC<15:8>
223
PWM1PRH
PR<7:0>
224
PWM1PRL
PR<15:8>
224
PWM1OFH
OF<7:0>
225
PWM1OFL
OF<15:8>
225
PWM1TMRH
TMR<7:0>
226
PWM1TMRL
TMR<15:8>
226
PWM1CON
EN
OE
OUT
POL
PWM1INTE
—
—
—
—
OFIE
PWM1INTF
—
—
—
—
PWM1CLKCON
—
PWM1LDCON
LDA
PWM1OFCON
—
—
—
216
PHIE
DCIE
PRIE
217
OFIF
PHIF
DCIF
—
—
—
—
OFO
—
PS<2:0>
LDT
—
OFM<1:0>
MODE<1:0>
PRIF
218
CS<1:0>
219
—
LDS<1:0>
220
—
OFS<1:0>
221
PWM2PHL
PH<7:0>
222
PWM2PHH
PH<15:8>
222
PWM2DCL
DC<7:0>
223
PWM2DCH
DC<15:8>
223
PWM2PRL
PR<7:0>
224
PWM2PRH
PR<15:8>
224
PWM2OFL
OF<7:0>
225
PWM2OFH
OF<15:8>
225
PWM2TMRL
TMR<7:0>
226
PWM2TMRH
TMR<15:8>
226
PWM2CON
EN
OE
OUT
POL
PWM2INTE
—
—
—
—
OFIE
PWM2INTF
—
—
—
—
PWM2CLKCON
—
PWM2LDCON
LDA
PWM2OFCON
—
—
—
216
PHIE
DCIE
PRIE
217
OFIF
PHIF
DCIF
—
—
—
—
OFO
—
PS<2:0>
LDT
—
OFM<1:0>
MODE<1:0>
PRIF
218
CS<1:0>
219
—
LDS<1:0>
220
—
OFS<1:0>
221
PWM3PHL
PH<7:0>
222
PWM3PHH
PH<15:8>
222
PWM3DCL
DC<7:0>
223
PWM3DCH
DC<15:8>
223
PWM3PRL
PR<7:0>
224
PWM3PRH
PR<15:8>
224
PWM3OFL
OF<7:0>
225
PWM3OFH
OF<15:8>
225
PWM3TMRL
TMR<7:0>
226
PWM3TMRH
TMR<15:8>
PWM3CON
EN
OE
OUT
POL
226
MODE<1:0>
—
—
216
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used by the PWM.
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TABLE 22-2:
SUMMARY OF REGISTERS ASSOCIATED WITH PWM (CONTINUED)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Register
on Page
PWM3INTE
—
—
—
—
OFIE
PHIE
DCIE
PRIE
217
PWM3INTF
—
—
—
—
OFIF
PHIF
DCIF
PRIF
PWM3CLKCON
—
—
—
—
—
OFO
—
Name
PS<2:0>
PWM3LDCON
LDA
PWM3OFCON
—
LDT
—
OFM<1:0>
218
CS<1:0>
219
—
LDS<1:0>
220
—
OFS<1:0>
221
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used by the PWM.
TABLE 22-3:
Name
CONFIG1
SUMMARY OF CONFIGURATION WORD WITH CLOCK SOURCES
Bits Bit -/7
Bit -/6
Bit 13/5
Bit 12/4
Bit 11/3
—
CLKOUTEN
13:8
—
—
—
7:0
CP
MCLRE
PWRTE
WDTE<1:0>
Bit 10/2
Bit 9/1
Bit 8/0
BOREN<1:0>
—
—
FOSC<1:0>
Register
on Page
42
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used by clock sources.
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DS40001723D-page 230
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23.0
COMPLEMENTARY WAVEFORM
GENERATOR (CWG) MODULE
The Complementary Waveform Generator (CWG)
produces a complementary waveform with dead-band
delay from a selection of input sources.
23.3
Selectable Input Sources
The CWG generates the output waveforms from the
input sources in Table 23-1.
TABLE 23-1:
The CWG module has the following features:
•
•
•
•
•
Selectable dead-band clock source control
Selectable input sources
Output enable control
Output polarity control
Dead-band control with independent 6-bit rising
and falling edge dead-band counters
• Auto-shutdown control with:
- Selectable shutdown sources
- Auto-restart enable
- Auto-shutdown pin override control
23.1
Fundamental Operation
The CWG generates two output waveforms from the
selected input source.
The off-to-on transition of each output can be delayed
from the on-to-off transition of the other output, thereby,
creating a time delay immediately where neither output
is driven. This is referred to as dead time and is covered
in Section 23.5 “Dead-Band Control”. A typical
operating waveform with dead band, generated from a
single input signal, is shown in Figure 23-2.
It may be necessary to guard against the possibility of
circuit Faults or a feedback event arriving too late, or
not at all. In this case, the active drive must be terminated before the Fault condition causes damage. This
is referred to as auto-shutdown and is covered in
Section 23.9 “Auto-Shutdown Control”.
23.2
Clock Source
The CWG module allows the following clock sources
to be selected:
• FOSC (system clock)
• HFINTOSC (16 MHz only)
SELECTABLE INPUT
SOURCES
Source Peripheral
Signal Name
Comparator C1
C1OUT_sync
PWM1
PWM1_output
PWM2
PWM2_output
PWM3
PWM3_output
The input sources are selected using the GxIS<2:0>
bits in the CWGxCON1 register (Register 23-2).
23.4
Output Control
Immediately after the CWG module is enabled, the
complementary drive is configured with both CWGxA
and CWGxB drives cleared.
23.4.1
OUTPUT ENABLES
Each CWG output pin has individual output enable
control. Output enables are selected with the GxOEA
and GxOEB bits of the CWGxCON0 register. When an
output enable control is cleared, the module asserts no
control over the pin. When an output enable is set, the
override value or active PWM waveform is applied to
the pin per the port priority selection. The output pin
enables are dependent on the module enable bit,
GxEN. When GxEN is cleared, CWG output enables
and CWG drive levels have no effect.
23.4.2
POLARITY CONTROL
The polarity of each CWG output can be selected
independently. When the output polarity bit is set, the
corresponding output is active-high. Clearing the output
polarity bit configures the corresponding output as
active-low. However, polarity does not affect the
override levels. Output polarity is selected with the
GxPOLA and GxPOLB bits of the CWGxCON0 register.
The clock sources are selected using the G1CS0 bit of
the CWGxCON0 register (Register 23-1).
 2013-2015 Microchip Technology Inc.
DS40001723D-page 231
SIMPLIFIED CWG BLOCK DIAGRAM
Rev. 10-000123D
7/10/2015
GxASDLA
2
00
GxCS
1
FOSC
10
‘1'
11
CWGxDBR
cwg_clock
GxASDLA = 01
6
HFINTOSC
GxIS
‘0'
C1OUT_async
Reserved
PWM1_out
PWM2_out
PWM3_out
Reserved
Reserved
Reserved
=
0
R
S
TRISx
Q
GxOEA
GxPOLA
Input Source
CWGxDBF
R
6
Q
GxOEB
EN
=
0
R
1
GxPOLB
00
 2013-2015 Microchip Technology Inc.
CWG1FLT (INT pin)
GxASDSFLT
S
Q
D
S
R
GxARSEN
10
‘1'
11
shutdown
Q
GxASDLB
GxASE Data Bit
WRITE
‘0'
GxASE
Auto-Shutdown
Source
C1OUT_async
GxASDSC1
x = CWG module number
CWGxA
1
EN
3
Q
set dominate
2
GxASDLB = 01
TRISx
CWGxB
PIC12(L)F1571/2
DS40001723D-page 232
FIGURE 23-1:
PIC12(L)F1571/2
FIGURE 23-2:
TYPICAL CWG OPERATION WITH PWM1 (NO AUTO-SHUTDOWN)
cwg_clock
PWM1
CWGxA
Rising Edge
Dead Band
Falling Edge Dead Band
Rising Edge
Rising Edge Dead Band
Falling Edge Dead Band Dead Band
CWGxB
23.5
Dead-Band Control
Dead-band control provides for non-overlapping output
signals to prevent shoot-through current in power
switches. The CWG contains two 6-bit dead-band
counters. One dead-band counter is used for the rising
edge of the input source control. The other is used for
the falling edge of the input source control.
Dead band is timed by counting CWG clock periods
from zero, up to the value in the rising or falling DeadBand Counter registers. See the CWGxDBR and
CWGxDBF registers (Register 23-4 and Register 23-5,
respectively).
23.6
Rising Edge Dead Band
The rising edge dead band delays the turn-on of the
CWGxA output from when the CWGxB output is turned
off. The rising edge dead-band time starts when the
rising edge of the input source signal goes true. When
this happens, the CWGxB output is immediately turned
off and the rising edge dead-band delay time starts.
When the rising edge dead-band delay time is reached,
the CWGxA output is turned on.
23.7
Falling Edge Dead Band
The falling edge dead band delays the turn-on of the
CWGxB output from when the CWGxA output is turned
off. The falling edge dead-band time starts when the
falling edge of the input source goes true. When this
happens, the CWGxA output is immediately turned off
and the falling edge dead-band delay time starts. When
the falling edge dead-band delay time is reached, the
CWGxB output is turned on.
The CWGxDBF register sets the duration of the deadband interval on the falling edge of the input source
signal. This duration is from 0 to 64 counts of
dead band.
Dead band is always counted off the edge on the input
source signal. A count of 0 (zero), indicates that no
dead band is present.
If the input source signal is not present for enough time
for the count to be completed, no output will be seen on
the respective output.
Refer to Figure 23-3 and Figure 23-4 for examples.
The CWGxDBR register sets the duration of the deadband interval on the rising edge of the input source
signal. This duration is from 0 to 64 counts of dead band.
Dead band is always counted off the edge on the input
source signal. A count of 0 (zero), indicates that no
dead band is present.
If the input source signal is not present for enough time
for the count to be completed, no output will be seen on
the respective output.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 233
DEAD-BAND OPERATION, CWGxDBR = 01h, CWGxDBF = 02h
cwg_clock
Input Source
CWGxA
CWGxB
FIGURE 23-4:
DEAD-BAND OPERATION, CWGxDBR = 03h, CWGxDBF = 04h, SOURCE SHORTER THAN DEAD BAND
cwg_clock
Input Source
CWGxA
 2013-2015 Microchip Technology Inc.
CWGxB
Source Shorter than Dead Band
PIC12(L)F1571/2
DS40001723D-page 234
FIGURE 23-3:
PIC12(L)F1571/2
23.8
Dead-Band Uncertainty
23.9
Auto-Shutdown Control
When the rising and falling edges of the input source
triggers the dead-band counters, the input may be
asynchronous. This will create some uncertainty in the
dead-band time delay. The maximum uncertainty is
equal to one CWG clock period. Refer to Equation 23-1
for more detail.
Auto-shutdown is a method to immediately override the
CWG output levels with specific overrides that allow for
safe shutdown of the circuit. The shutdown state can be
either cleared automatically or held until cleared by
software.
EQUATION 23-1:
The shutdown state can be entered by either of the
following two methods:
DEAD-BAND
UNCERTAINTY
1
TDEADBAND_UNCERTAINTY = ----------------------------Fcwg_clock
23.9.1
SHUTDOWN
• Software generated
• External Input
23.9.1.1
Software Generated Shutdown
Setting the GxASE bit of the CWGxCON2 register will
force the CWG into the shutdown state.
When auto-restart is disabled, the shutdown state will
persist as long as the GxASE bit is set.
Example:
Fcwg_clock = 16 MHz
When auto-restart is enabled, the GxASE bit will clear
automatically and resume operation on the next rising
edge event. See Figure 23-6.
23.9.1.2
Therefore:
1
TDEADBAND_UNCERTAINTY = ----------------------------Fcwg_clock
1
= ------------------16 MHz
= 62.5ns
External shutdown inputs provide the fastest way to
safely suspend CWG operation in the event of a Fault
condition. When any of the selected shutdown inputs
goes active, the CWG outputs will immediately go to
the selected override levels without software delay. Any
combination of two input sources can be selected to
cause a shutdown condition. The sources are:
• Comparator C1 – C1OUT_async
• CWG1FLT
Shutdown inputs are selected in the CWGxCON2
register (Register 23-3).
Note:
 2013-2015 Microchip Technology Inc.
External Input Source
Shutdown inputs are level sensitive, not
edge sensitive. The shutdown state
cannot be cleared, except by disabling
auto-shutdown, as long as the shutdown
input level persists.
DS40001723D-page 235
PIC12(L)F1571/2
23.10 Operation During Sleep
23.11.1
The CWG module operates independently from the
system clock, and will continue to run during Sleep
provided that the clock and input sources selected
remain active.
The levels driven to the output pins, while the shutdown
input is true, are controlled by the GxASDLA
and GxASDLB bits of the CWGxCON1 register
(Register 23-3). GxASDLA controls the CWG1A override level and GxASDLB controls the CWG1B override
level. The control bit logic level corresponds to the output logic drive level while in the shutdown state. The
polarity control does not apply to the override level.
The HFINTOSC remains active during Sleep, provided
that the CWG module is enabled, the input source is
active and the HFINTOSC is selected as the clock
source, regardless of the system clock source
selected.
In other words, if the HFINTOSC is simultaneously
selected as the system clock and the CWG clock
source, when the CWG is enabled and the input source
is active, the CPU will go idle during Sleep, but the
CWG will continue to operate and the HFINTOSC will
remain active.
This will have a direct effect on the Sleep mode current.
23.11 Configuring the CWG
The following steps illustrate how to properly configure
the CWG to ensure a synchronous start:
1.
2.
3.
4.
5.
6.
7.
8.
9.
Ensure that the TRISx control bits corresponding to CWGxA and CWGxB are set so that both
are configured as inputs.
Clear the GxEN bit if not already cleared.
Set desired dead-band times with the CWGxDBR
and CWGxDBF registers.
Set up the following controls in the CWGxCON2
auto-shutdown register:
• Select desired shutdown source.
• Select both output overrides to the desired
levels (this is necessary even if not using
auto-shutdown because start-up will be from
a shutdown state).
• Set the GxASE bit and clear the GxARSEN
bit.
Select the desired input source using the
CWGxCON1 register.
Configure the following controls in the
CWGxCON0 register:
• Select desired clock source.
• Select the desired output polarities.
• Set the output enables for the outputs to be
used.
Set the GxEN bit.
Clear the TRISx control bits corresponding to
CWGxA and CWGxB to be used to configure
those pins as outputs.
If auto-restart is to be used, set the GxARSEN
bit and the GxASE bit will be cleared automatically. Otherwise, clear the GxASE bit to start the
CWG.
DS40001723D-page 236
23.11.2
PIN OVERRIDE LEVELS
AUTO-SHUTDOWN RESTART
After an auto-shutdown event has occurred, there are
two ways to resume operation:
• Software controlled
• Auto-restart
The restart method is selected with the GxARSEN bit
of the CWGxCON2 register. Waveforms of software
controlled and automatic restarts are shown in
Figure 23-5 and Figure 23-6.
23.11.2.1
Software Controlled Restart
When the GxARSEN bit of the CWGxCON2 register
is cleared, the CWG must be restarted after an
auto-shutdown event by software.
Clearing the shutdown state requires all selected shutdown inputs to be low, otherwise, the GxASE bit will
remain set. The overrides will remain in effect until the
first rising edge event after the GxASE bit is cleared.
The CWG will then resume operation.
23.11.2.2
Auto-Restart
When the GxARSEN bit of the CWGxCON2 register is
set, the CWG will restart from the auto-shutdown state
automatically.
The GxASE bit will clear automatically when all shutdown sources go low. The overrides will remain in
effect until the first rising edge event after the GxASE
bit is cleared. The CWG will then resume operation.
 2013-2015 Microchip Technology Inc.
 2013-2015 Microchip Technology Inc.
FIGURE 23-5:
SHUTDOWN FUNCTIONALITY, AUTO-RESTART DISABLED (GxARSEN = 0, GxASDLA = 01, GxASDLB = 01)
Shutdown Event Ceases
GxASE Cleared by Software
CWG Input
Source
Shutdown Source
GxASE
CWG1A
Tri-State (No Pulse)
CWG1B
Tri-State (No Pulse)
No Shutdown
Output Resumes
Shutdown
FIGURE 23-6:
SHUTDOWN FUNCTIONALITY, AUTO-RESTART ENABLED (GxARSEN = 1, GxASDLA = 01, GxASDLB = 01)
Shutdown Event Ceases
GxASE Auto-Cleared by Hardware
CWG Input
Source
GxASE
DS40001723D-page 237
CWG1A
Tri-State (No Pulse)
CWG1B
Tri-State (No Pulse)
No Shutdown
Shutdown
Output Resumes
PIC12(L)F1571/2
Shutdown Source
PIC12(L)F1571/2
23.12 Register Definitions: CWG Control
REGISTER 23-1:
CWGxCON0: CWGx CONTROL REGISTER 0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
U-0
U-0
R/W-0/0
GxEN
GxOEB
GxOEA
GxPOLB
GxPOLA
—
—
GxCS0
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
GxEN: CWGx Enable bit
1 = Module is enabled
0 = Module is disabled
bit 6
GxOEB: CWGxB Output Enable bit
1 = CWGxB is available on appropriate I/O pin
0 = CWGxB is not available on appropriate I/O pin
bit 5
GxOEA: CWGxA Output Enable bit
1 = CWGxA is available on appropriate I/O pin
0 = CWGxA is not available on appropriate I/O pin
bit 4
GxPOLB: CWGxB Output Polarity bit
1 = Output is inverted polarity
0 = Output is normal polarity
bit 3
GxPOLA: CWGxA Output Polarity bit
1 = Output is inverted polarity
0 = Output is normal polarity
bit 2-1
Unimplemented: Read as ‘0’
bit 0
GxCS0: CWGx Clock Source Select bit
1 = HFINTOSC
0 = FOSC
DS40001723D-page 238
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
REGISTER 23-2:
R/W-x/u
CWGxCON1: CWGx CONTROL REGISTER 1
R/W-x/u
R/W-x/u
GxASDLB<1:0>
R/W-x/u
U-0
GxASDLA<1:0>
—
R/W-0/0
R/W-0/0
R/W-0/0
GxIS<2:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7-6
GxASDLB<1:0>: CWGx Shutdown State for CWGxB bits
When an Auto-Shutdown Event is Present (GxASE = 1):
11 = CWGxB pin is driven to ‘1’, regardless of the setting of the GxPOLB bit
10 = CWGxB pin is driven to ‘0’, regardless of the setting of the GxPOLB bit
01 = CWGxB pin is tri-stated
00 = CWGxB pin is driven to its inactive state after the selected dead-band interval; GxPOLB will still
control the polarity of the output
bit 5-4
GxASDLA<1:0>: CWGx Shutdown State for CWGxA bits
When an Auto-Shutdown Event is Present (GxASE = 1):
11 = CWGxA pin is driven to ‘1’, regardless of the setting of the GxPOLA bit
10 = CWGxA pin is driven to ‘0’, regardless of the setting of the GxPOLA bit
01 = CWGxA pin is tri-stated
00 = CWGxA pin is driven to its inactive state after the selected dead-band interval; GxPOLA will still
control the polarity of the output
bit 3
Unimplemented: Read as ‘0’
bit 2-0
GxIS<2:0>: CWGx Input Source Select bits
111 = Reserved
110 = Reserved
101 = Reserved
100 = PWM3 – PWM3_out
011 = PWM2 – PWM2_out
010 = PWM1 – PWM1_out
001 = Reserved
000 = Comparator C1 – C1OUT_async
 2013-2015 Microchip Technology Inc.
DS40001723D-page 239
PIC12(L)F1571/2
REGISTER 23-3:
CWGxCON2: CWGx CONTROL REGISTER 2
R/W-0/0
R/W-0/0
U-0
U-0
U-0
R/W-0/0
R/W-0/0
U-0
GxASE
GxARSEN
—
—
—
GxASDSC1
GxASDSFLT
—
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
u = Bit is unchanged
x = Bit is unknown
U = Unimplemented bit, read as ‘0’
‘1’ = Bit is set
‘0’ = Bit is cleared
-n/n = Value at POR and BOR/Value at all other Resets
bit 7
GxASE: Auto-Shutdown Event Status bit
1 = An auto-shutdown event has occurred
0 = No auto-shutdown event has occurred
bit 6
GxARSEN: Auto-Restart Enable bit
1 = Auto-restart is enabled
0 = Auto-restart is disabled
bit 5-3
Unimplemented: Read as ‘0’
bit 2
GxASDSC1: CWGx Auto-Shutdown on Comparator C1 Enable bit
1 = Shutdown when Comparator C1 output (C1OUT_async) is high
0 = Comparator C1 output has no effect on shutdown
bit 1
GxASDSFLT: CWGx Auto-Shutdown on FLT Enable bit
1 = Shutdown when CWG1FLT input is low
0 = CWG1FLT input has no effect on shutdown
bit 0
Unimplemented: Read as ‘0’
DS40001723D-page 240
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
REGISTER 23-4:
CWGxDBR: CWGx COMPLEMENTARY WAVEFORM GENERATOR RISING
DEAD-BAND COUNT REGISTER
U-0
U-0
—
—
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
CWGxDBR<5:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
q = Value depends on condition
bit 7-6
Unimplemented: Read as ‘0’
bit 5-0
CWGxDBR<5:0>: Complementary Waveform Generator (CWGx) Rising Counts bits
11 1111 = 63-64 counts of dead band
11 1110 = 62-63 counts of dead band
•
•
•
00 0010 = 2-3 counts of dead band
00 0001 = 1-2 counts of dead band
00 0000 = 0 counts of dead band
REGISTER 23-5:
CWGxDBF: CWGx COMPLEMENTARY WAVEFORM GENERATOR FALLING
DEAD-BAND COUNT REGISTER
U-0
U-0
—
—
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
R/W-x/u
CWGxDBF<5:0>
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
q = Value depends on condition
bit 7-6
Unimplemented: Read as ‘0’
bit 5-0
CWGxDBF<5:0>: Complementary Waveform Generator (CWGx) Falling Counts bits
11 1111 = 63-64 counts of dead band
11 1110 = 62-63 counts of dead band
•
•
•
00 0010 = 2-3 counts of dead band
00 0001 = 1-2 counts of dead band
00 0000 = 0 counts of dead band; dead-band generation is bypassed
 2013-2015 Microchip Technology Inc.
DS40001723D-page 241
PIC12(L)F1571/2
TABLE 23-2:
Name
ANSELA
CWG1CON0
CWG1CON1
SUMMARY OF REGISTERS ASSOCIATED WITH CWG
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Register
on Page
—
—
—
ANSA4
—
ANSA2
ANSA1
ANSA0
114
G1EN
G1OEB
—
—
G1CS0
238
G1ASDLB<1:0>
CWG1CON2 G1ASE G1ARSEN
CWG1DBF
—
—
CWG1DBR
—
—
TRISA
—
—
G1OEA G1POLB G1POLA
G1ASDLA<1:0>
—
—
—
—
—
G1IS<1:0>
G1ASDSC1 G1ASDSFLT
239
—
CWG1DBF<5:0>
241
CWG1DBR<5:0>
TRISA<5:4>
—(1)
TRISA2
240
241
TRISA<1:0>
113
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used by the CWG.
Note 1: Unimplemented, read as ‘1’.
DS40001723D-page 242
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
24.0
IN-CIRCUIT SERIAL
PROGRAMMING™ (ICSP™)
ICSP™ programming allows customers to manufacture
circuit boards with unprogrammed devices. Programming
can be done after the assembly process, allowing the
device to be programmed with the most recent firmware
or a custom firmware. Five pins are needed for ICSP™
programming:
• ICSPCLK
• ICSPDAT
• MCLR/VPP
• VDD
• VSS
In Program/Verify mode, the program memory, User IDs
and the Configuration Words are programmed through
serial communications. The ICSPDAT pin is a bidirectional I/O used for transferring the serial data and the
ICSPCLK pin is the clock input. For more information on
ICSP™, refer to the “PIC12(L)F1501/PIC16(L)F150X
Memory Programming Specification” (DS41573).
24.1
High-Voltage Programming Entry
Mode
The device is placed into High-Voltage Programming
Entry mode by holding the ICSPCLK and ICSPDAT pins
low, then raising the voltage on MCLR/VPP to VIHH.
24.2
Low-Voltage Programming Entry
Mode
The Low-Voltage Programming Entry mode allows the
PIC® MCUs (Flash) to be programmed using VDD only,
without high voltage. When the LVP bit of the
Configuration Words is set to ‘1’, the ICSP Low-Voltage
Programming Entry mode is enabled. To disable the
Low-Voltage ICSP mode, the LVP bit must be
programmed to ‘0’.
24.3
Common Programming Interfaces
Connection to a target device is typically done through
an ICSP™ header. A commonly found connector on
development tools is the RJ-11 in the 6P6C (6-pin,
6-connector) configuration. See Figure 24-1.
FIGURE 24-1:
VDD
ICD RJ-11 STYLE
CONNECTOR INTERFACE
ICSPDAT
NC
2 4 6
ICSPCLK
1 3 5
Target
VPP/MCLR
VSS
PC Board
Bottom Side
Pin Description*
1 = VPP/MCLR
2 = VDD Target
3 = VSS (ground)
4 = ICSPDAT
5 = ICSPCLK
6 = No Connect
Another connector often found in use with the PICkit™
programmers is a standard 6-pin header with 0.1 inch
spacing. Refer to Figure 24-2.
Entry into the Low-Voltage Programming Entry mode
requires the following steps:
1.
2.
MCLR is brought to VIL.
A 32-bit key sequence is presented on
ICSPDAT while clocking ICSPCLK.
Once the key sequence is complete, MCLR must be
held at VIL for as long as Program/Verify mode is to be
maintained.
If Low-Voltage Programming is enabled (LVP = 1), the
MCLR Reset function is automatically enabled and
cannot be disabled. See Section 6.5 “MCLR” for more
information.
The LVP bit can only be reprogrammed to ‘0’ by using
the High-Voltage Programming mode.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 243
PIC12(L)F1571/2
FIGURE 24-2:
PICkit™ PROGRAMMER STYLE CONNECTOR INTERFACE
Rev. 10-000128A
7/30/2013
Pin 1 Indicator
Pin Description*
1 = VPP/MCLR
1
2
3
4
5
6
2 = VDD Target
3 = VSS (ground)
4 = ICSPDAT
5 = ICSPCLK
6 = No connect
* The 6-pin header (0.100" spacing) accepts 0.025" square pins
For additional interface recommendations, refer to your
specific device programmer manual prior to PCB
design.
FIGURE 24-3:
It is recommended that isolation devices be used to
separate the programming pins from other circuitry.
The type of isolation is highly dependent on the specific
application and may include devices, such as resistors,
diodes or even jumpers. See Figure 24-3 for more
information.
TYPICAL CONNECTION FOR ICSP™ PROGRAMMING
Rev. 10-000129A
7/30/2013
External
Programming
Signals
Device to be
Programmed
VDD
VDD
VDD
VPP
MCLR/VPP
VSS
VSS
Data
ICSPDAT
Clock
ICSPCLK
*
*
*
To Normal Connections
* Isolation devices (as required).
DS40001723D-page 244
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
25.0
INSTRUCTION SET SUMMARY
25.1
Read-Modify-Write Operations
• Byte-Oriented
• Bit-Oriented
• Literal and Control
Any instruction that specifies a file register as part of
the instruction performs a Read-Modify-Write (R-M-W)
operation. The register is read, the data is modified and
the result is stored according to either the instruction or
the destination designator, ‘d’. A read operation is
performed on a register even if the instruction writes to
that register.
The literal and control category contains the most
varied instruction word format.
TABLE 25-1:
Each instruction is a 14-bit word containing the operation code (opcode) and all required operands. The
opcodes are broken into three broad categories.
OPCODE FIELD
DESCRIPTIONS
Table 25-3 lists the instructions recognized by the
MPASM™ assembler.
Field
All instructions are executed within a single instruction
cycle, with the following exceptions, which may take
two or three cycles:
W
Working register (accumulator).
b
Bit address within an 8-bit file register.
k
Literal field, constant data or label.
x
Don’t care location (= 0 or 1).
The assembler will generate code with x = 0.
It is the recommended form of use for
compatibility with all Microchip software tools.
d
Destination select; d = 0: store result in W,
d = 1: store result in file register f.
Default is d = 1.
n
FSR or INDF number (0-1).
• Subroutine takes two cycles (CALL, CALLW)
• Returns from interrupts or subroutines take two
cycles (RETURN, RETLW, RETFIE)
• Program branching takes two cycles (GOTO, BRA,
BRW, BTFSS, BTFSC, DECFSZ, INCSFZ)
• One additional instruction cycle will be used when
any instruction references an indirect file register
and the file select register is pointing to program
memory
One instruction cycle consists of 4 oscillator cycles; for
an oscillator frequency of 4 MHz, this gives a nominal
instruction execution rate of 1 MHz.
All instruction examples use the format ‘0xhh’ to
represent a hexadecimal number, where ‘h’ signifies a
hexadecimal digit.
f
mm
Description
Register file address (0x00 to 0x7F).
Pre-Post Increment-Decrement mode
selection.
TABLE 25-2:
ABBREVIATION
DESCRIPTIONS
Field
PC
TO
C
DC
Z
PD
 2013-2015 Microchip Technology Inc.
Description
Program Counter
Time-out bit
Carry bit
Digit Carry bit
Zero bit
Power-Down bit
DS40001723D-page 245
PIC12(L)F1571/2
FIGURE 25-1:
GENERAL FORMAT FOR
INSTRUCTIONS
Byte-oriented file register operations
13
8 7 6
OPCODE
d
f (FILE #)
0
d = 0 for destination W
d = 1 for destination f
f = 7-bit file register address
Bit-oriented file register operations
13
10 9
7 6
OPCODE
b (BIT #)
f (FILE #)
0
b = 3-bit bit address
f = 7-bit file register address
Literal and control operations
General
13
OPCODE
8
7
0
k (literal)
k = 8-bit immediate value
CALL and GOTO instructions only
13
11 10
OPCODE
0
k (literal)
k = 11-bit immediate value
MOVLP instruction only
13
OPCODE
7
6
0
k (literal)
k = 7-bit immediate value
MOVLB instruction only
13
OPCODE
5 4
0
k (literal)
k = 5-bit immediate value
BRA instruction only
13
OPCODE
9
8
0
k (literal)
k = 9-bit immediate value
FSR Offset instructions
13
OPCODE
7
6
n
5
0
k (literal)
n = appropriate FSR
k = 6-bit immediate value
FSR Increment instructions
13
OPCODE
3
2 1
0
n m (mode)
n = appropriate FSR
m = 2-bit mode value
OPCODE only
13
0
OPCODE
DS40001723D-page 246
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
TABLE 25-3:
ENHANCED MID-RANGE INSTRUCTION SET
Mnemonic,
Operands
Description
Cycles
14-Bit Opcode
MSb
LSb
Status
Affected
Notes
BYTE-ORIENTED FILE REGISTER OPERATIONS
ADDWF
ADDWFC
ANDWF
ASRF
LSLF
LSRF
CLRF
CLRW
COMF
DECF
INCF
IORWF
MOVF
MOVWF
RLF
RRF
SUBWF
SUBWFB
SWAPF
XORWF
f, d
f, d
f, d
f, d
f, d
f, d
f
–
f, d
f, d
f, d
f, d
f, d
f
f, d
f, d
f, d
f, d
f, d
f, d
Add W and f
Add with Carry W and f
AND W with f
Arithmetic Right Shift
Logical Left Shift
Logical Right Shift
Clear f
Clear W
Complement f
Decrement f
Increment f
Inclusive OR W with f
Move f
Move W to f
Rotate Left f through Carry
Rotate Right f through Carry
Subtract W from f
Subtract with Borrow W from f
Swap nibbles in f
Exclusive OR W with f
DECFSZ
INCFSZ
f, d
f, d
Decrement f, Skip if 0
Increment f, Skip if 0
BCF
BSF
f, b
f, b
Bit Clear f
Bit Set f
BTFSC
BTFSS
f, b
f, b
Bit Test f, Skip if Clear
Bit Test f, Skip if Set
ADDLW
ANDLW
IORLW
MOVLB
MOVLP
MOVLW
SUBLW
XORLW
k
k
k
k
k
k
k
k
Add literal and W
AND literal with W
Inclusive OR literal with W
Move literal to BSR
Move literal to PCLATH
Move literal to W
Subtract W from literal
Exclusive OR literal with W
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
00
11
00
11
11
11
00
00
00
00
00
00
00
00
00
00
00
11
00
00
0111
1101
0101
0111
0101
0110
0001
0001
1001
0011
1010
0100
1000
0000
1101
1100
0010
1011
1110
0110
dfff
dfff
dfff
dfff
dfff
dfff
lfff
0000
dfff
dfff
dfff
dfff
dfff
1fff
dfff
dfff
dfff
dfff
dfff
dfff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
00xx
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
C, DC, Z
C, DC, Z
Z
C, Z
C, Z
C, Z
Z
Z
Z
Z
Z
Z
Z
C
C
C, DC, Z
C, DC, Z
Z
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
BYTE-ORIENTED SKIP OPERATIONS
1(2)
1(2)
00
00
1, 2
1, 2
1011 dfff ffff
1111 dfff ffff
BIT-ORIENTED FILE REGISTER OPERATIONS
1
1
00bb bfff ffff
01bb bfff ffff
2
2
01
01
10bb bfff ffff
11bb bfff ffff
1, 2
1, 2
11
11
11
00
11
11
11
11
1110
1001
1000
0000
0001
0000
1100
1010
01
01
BIT-ORIENTED SKIP OPERATIONS
1 (2)
1 (2)
LITERAL OPERATIONS
1
1
1
1
1
1
1
1
kkkk
kkkk
kkkk
001k
1kkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
C, DC, Z
Z
Z
C, DC, Z
Z
Note 1: If the Program Counter (PC) is modified, or a conditional test is true, the instruction requires two cycles. The second cycle
is executed as a NOP.
2: If this instruction addresses an INDF register and the MSb of the corresponding FSR is set, this instruction will require one
additional instruction cycle.
3: See the table in the MOVIW and MOVWI instruction descriptions.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 247
PIC12(L)F1571/2
TABLE 25-3:
ENHANCED MID-RANGE INSTRUCTION SET (CONTINUED)
Mnemonic,
Operands
Description
Cycles
14-Bit Opcode
MSb
LSb
Status
Affected
Notes
CONTROL OPERATIONS
BRA
BRW
CALL
CALLW
GOTO
RETFIE
RETLW
RETURN
k
–
k
–
k
k
k
–
Relative Branch
Relative Branch with W
Call Subroutine
Call Subroutine with W
Go to address
Return from interrupt
Return with literal in W
Return from Subroutine
2
2
2
2
2
2
2
2
11
00
10
00
10
00
11
00
001k
0000
0kkk
0000
1kkk
0000
0100
0000
kkkk
0000
kkkk
0000
kkkk
0000
kkkk
0000
kkkk
1011
kkkk
1010
kkkk
1001
kkkk
1000
00
00
00
00
00
00
0000
0000
0000
0000
0000
0000
0110
0000
0110
0000
0110
0110
0100 TO, PD
0000
0010
0001
0011 TO, PD
0fff
INHERENT OPERATIONS
CLRWDT
NOP
OPTION
RESET
SLEEP
TRIS
–
–
–
–
–
f
Clear Watchdog Timer
No Operation
Load OPTION_REG register with W
Software device Reset
Go into Standby mode
Load TRIS register with W
ADDFSR
MOVIW
n, k
n mm
MOVWI
k[n]
n mm
Add Literal k to FSRn
Move Indirect FSRn to W with pre/post inc/dec
modifier, mm
Move INDFn to W, Indexed Indirect.
Move W to Indirect FSRn with pre/post inc/dec
modifier, mm
Move W to INDFn, Indexed Indirect.
1
1
1
1
1
1
C COMPILER OPTIMIZED
k[n]
1
1
11
00
1
1
11
00
0001 0nkk kkkk
0000 0001 0nmm Z
kkkk
1111 0nkk 1nmm Z
0000 0001 kkkk
1
11
1111 1nkk
2, 3
2
2, 3
2
Note 1: If the Program Counter (PC) is modified, or a conditional test is true, the instruction requires two cycles. The second cycle
is executed as a NOP.
2: If this instruction addresses an INDF register and the MSb of the corresponding FSR is set, this instruction will require
one additional instruction cycle.
3: See the table in the MOVIW and MOVWI instruction descriptions.
DS40001723D-page 248
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
25.2
Instruction Descriptions
ADDFSR
Add Literal to FSRn
ANDLW
AND literal with W
Syntax:
[ label ] ADDFSR FSRn, k
Syntax:
[ label ] ANDLW
Operands:
-32  k  31
n  [ 0, 1]
Operation:
FSR(n) + k  FSR(n)
Status Affected:
None
Description:
The signed 6-bit literal ‘k’ is added to
the contents of the FSRnH:FSRnL
register pair.
k
Operands:
0  k  255
Operation:
(W) .AND. (k)  (W)
Status Affected:
Z
Description:
The contents of W register are
AND’ed with the 8-bit literal ‘k’. The
result is placed in the W register.
FSRn is limited to the range 0000h FFFFh. Moving beyond these bounds
will cause the FSR to wraparound.
ADDLW
Add literal and W
ANDWF
AND W with f
Syntax:
[ label ] ADDLW
Syntax:
[ label ] ANDWF
Operands:
0  f  127
d 0,1
Operation:
(W) .AND. (f)  (destination)
The contents of the W register are
added to the 8-bit literal ‘k’ and the
result is placed in the W register.
Status Affected:
Z
Description:
AND the W register with register ‘f’. If
‘d’ is ‘0’, the result is stored in the W
register. If ‘d’ is ‘1’, the result is stored
back in register ‘f’.
ADDWF
Add W and f
ASRF
Arithmetic Right Shift
Syntax:
[ label ] ADDWF
Syntax:
[ label ] ASRF
Operands:
0  f  127
d 0,1
Operands:
0  f  127
d [0,1]
Operation:
(W) + (f)  (destination)
Operation:
Status Affected:
C, DC, Z
Description:
Add the contents of the W register
with register ‘f’. If ‘d’ is ‘0’, the result is
stored in the W register. If ‘d’ is ‘1’, the
result is stored back in register ‘f’.
(f<7>) dest<7>
(f<7:1>)  dest<6:0>,
(f<0>)  C,
Status Affected:
C, Z
Description:
The contents of register ‘f’ are shifted
one bit to the right through the Carry
flag. The MSb remains unchanged. If
‘d’ is ‘0’, the result is placed in W. If ‘d’
is ‘1’, the result is stored back in
register ‘f’.
Operands:
0  k  255
Operation:
(W) + k  (W)
Status Affected:
C, DC, Z
Description:
k
f,d
ADDWFC
ADD W and CARRY bit to f
Syntax:
[ label ] ADDWFC
Operands:
0  f  127
d [0,1]
f {,d}
register f
C
f {,d}
Operation:
(W) + (f) + (C)  dest
Status Affected:
C, DC, Z
Description:
Add W, the Carry flag and data memory location ‘f’. If ‘d’ is ‘0’, the result is
placed in W. If ‘d’ is ‘1’, the result is
placed in data memory location ‘f’.
 2013-2015 Microchip Technology Inc.
f,d
DS40001723D-page 249
PIC12(L)F1571/2
BCF
Bit Clear f
Syntax:
[ label ] BCF
BTFSC
f,b
Bit Test f, Skip if Clear
Syntax:
[ label ] BTFSC f,b
0  f  127
0b7
Operands:
0  f  127
0b7
Operands:
Operation:
0  (f<b>)
Operation:
skip if (f<b>) = 0
Status Affected:
None
Status Affected:
None
Description:
Bit ‘b’ in register ‘f’ is cleared.
Description:
If bit ‘b’ in register ‘f’ is ‘1’, the next
instruction is executed.
If bit ‘b’, in register ‘f’, is ‘0’, the next
instruction is discarded, and a NOP is
executed instead, making this a
2-cycle instruction.
BRA
Relative Branch
BTFSS
Bit Test f, Skip if Set
Syntax:
[ label ] BRA label
[ label ] BRA $+k
Syntax:
[ label ] BTFSS f,b
Operands:
0  f  127
0b<7
Operands:
-256  label - PC + 1  255
-256  k  255
Operation:
skip if (f<b>) = 1
Operation:
(PC) + 1 + k  PC
Status Affected:
None
Status Affected:
None
Description:
Description:
Add the signed 9-bit literal ‘k’ to the
PC. Since the PC will have incremented to fetch the next instruction,
the new address will be PC + 1 + k.
This instruction is a 2-cycle instruction. This branch has a limited range.
If bit ‘b’ in register ‘f’ is ‘0’, the next
instruction is executed.
If bit ‘b’ is ‘1’, then the next
instruction is discarded and a NOP is
executed instead, making this a
2-cycle instruction.
BRW
Relative Branch with W
Syntax:
[ label ] BRW
Operands:
None
Operation:
(PC) + (W)  PC
Status Affected:
None
Description:
Add the contents of W (unsigned) to
the PC. Since the PC will have incremented to fetch the next instruction,
the new address will be PC + 1 + (W).
This instruction is a 2-cycle instruction.
BSF
Bit Set f
Syntax:
[ label ] BSF
Operands:
0  f  127
0b7
Operation:
1  (f<b>)
Status Affected:
None
Description:
Bit ‘b’ in register ‘f’ is set.
DS40001723D-page 250
f,b
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
CALL
Call Subroutine
CLRWDT
Clear Watchdog Timer
Syntax:
[ label ] CALL k
Syntax:
[ label ] CLRWDT
Operands:
0  k  2047
Operands:
None
Operation:
(PC)+ 1 TOS,
k  PC<10:0>,
(PCLATH<6:3>)  PC<14:11>
Operation:
Status Affected:
None
00h  WDT
0  WDT prescaler,
1  TO
1  PD
Description:
Call Subroutine. First, return address
(PC + 1) is pushed onto the stack.
The 11-bit immediate address is
loaded into PC bits <10:0>. The upper
bits of the PC are loaded from
PCLATH. CALL is a 2-cycle instruction.
Status Affected:
TO, PD
Description:
CLRWDT instruction resets the Watchdog Timer. It also resets the prescaler
of the WDT.
Status bits TO and PD are set.
CALLW
Subroutine Call With W
COMF
Complement f
Syntax:
[ label ] CALLW
Syntax:
[ label ] COMF
Operands:
None
Operands:
Operation:
(PC) +1  TOS,
(W)  PC<7:0>,
(PCLATH<6:0>) PC<14:8>
0  f  127
d  [0,1]
Operation:
(f)  (destination)
Status Affected:
Z
Description:
The contents of register ‘f’ are complemented. If ‘d’ is ‘0’, the result is
stored in W. If ‘d’ is ‘1’, the result is
stored back in register ‘f’.
DECF
Decrement f
Status Affected:
None
Description:
Subroutine call with W. First, the
return address (PC + 1) is pushed
onto the return stack. Then, the contents of W is loaded into PC<7:0>,
and the contents of PCLATH into
PC<14:8>. CALLW is a 2-cycle
instruction.
CLRF
Clear f
Syntax:
[ label ] CLRF
f
f,d
Syntax:
[ label ] DECF f,d
0  f  127
d  [0,1]
Operands:
0  f  127
Operands:
Operation:
00h  (f)
1Z
Operation:
(f) - 1  (destination)
Z
Status Affected:
Z
Description:
The contents of register ‘f’ are cleared
and the Z bit is set.
Description:
Decrement register ‘f’. If ‘d’ is ‘0’, the
result is stored in the W
register. If ‘d’ is ‘1’, the result is stored
back in register ‘f’.
CLRW
Clear W
Syntax:
[ label ] CLRW
Operands:
None
Operation:
00h  (W)
1Z
Status Affected:
Status Affected:
Z
Description:
W register is cleared. Zero bit (Z) is
set.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 251
PIC12(L)F1571/2
DECFSZ
Decrement f, Skip if 0
INCFSZ
Syntax:
[ label ] DECFSZ f,d
Syntax:
[ label ]
Operands:
0  f  127
d  [0,1]
Operands:
0  f  127
d  [0,1]
Operation:
(f) - 1  (destination);
skip if result = 0
Operation:
(f) + 1  (destination),
skip if result = 0
Status Affected:
None
Status Affected:
None
Description:
The contents of register ‘f’ are decremented. If ‘d’ is ‘0’, the result is placed
in the W register. If ‘d’ is ‘1’, the result
is placed back in register ‘f’.
If the result is ‘1’, the next instruction is
executed. If the result is ‘0’, then a
NOP is executed instead, making it a
2-cycle instruction.
Description:
The contents of register ‘f’ are incremented. If ‘d’ is ‘0’, the result is placed
in the W register. If ‘d’ is ‘1’, the result
is placed back in register ‘f’.
If the result is ‘1’, the next instruction is
executed. If the result is ‘0’, a NOP is
executed instead, making it a 2-cycle
instruction.
GOTO
Unconditional Branch
IORLW
Inclusive OR literal with W
Syntax:
[ label ]
Syntax:
[ label ]
GOTO k
Increment f, Skip if 0
INCFSZ f,d
IORLW k
Operands:
0  k  2047
Operands:
0  k  255
Operation:
k  PC<10:0>
PCLATH<6:3>  PC<14:11>
Operation:
(W) .OR. k  (W)
Status Affected:
None
Description:
GOTO is an unconditional branch. The
11-bit immediate value is loaded into
PC bits <10:0>. The upper bits of PC
are loaded from PCLATH<4:3>. GOTO
is a 2-cycle instruction.
INCF
Status Affected:
Z
Description:
The contents of the W register are
OR’ed with the 8-bit literal ‘k’. The
result is placed in the W register.
Increment f
IORWF
Inclusive OR W with f
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
0  f  127
d  [0,1]
Operands:
0  f  127
d  [0,1]
Operation:
(f) + 1  (destination)
Operation:
(W) .OR. (f)  (destination)
Status Affected:
Z
Status Affected:
Z
Description:
The contents of register ‘f’ are incremented. If ‘d’ is ‘0’, the result is placed
in the W register. If ‘d’ is ‘1’, the result
is placed back in register ‘f’.
Description:
Inclusive OR the W register with register ‘f’. If ‘d’ is ‘0’, the result is placed in
the W register. If ‘d’ is ‘1’, the result is
placed back in register ‘f’.
DS40001723D-page 252
INCF f,d
IORWF
f,d
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
LSLF
Logical Left Shift
MOVF
Syntax:
[ label ] LSLF
Syntax:
[ label ]
Operands:
0  f  127
d [0,1]
Operands:
0  f  127
d  [0,1]
Operation:
(f<7>)  C
(f<6:0>)  dest<7:1>
0  dest<0>
Operation:
(f)  (dest)
f {,d}
Status Affected:
C, Z
Description:
The contents of register ‘f’ are shifted
one bit to the left through the Carry flag.
A ‘0’ is shifted into the LSb. If ‘d’ is ‘0’,
the result is placed in W. If ‘d’ is ‘1’, the
result is stored back in register ‘f’.
C
register f
0
Z
Description:
The contents of register f is moved to
a destination dependent upon the
status of d. If d = 0,
destination is W register. If d = 1, the
destination is file register f itself. d = 1
is useful to test a file register since
status flag Z is affected.
Words:
1
Cycles:
1
Logical Right Shift
Syntax:
[ label ] LSRF
Operands:
0  f  127
d [0,1]
Operation:
0  dest<7>
(f<7:1>)  dest<6:0>,
(f<0>)  C,
Status Affected:
C, Z
Description:
The contents of register ‘f’ are shifted
one bit to the right through the Carry
flag. A ‘0’ is shifted into the MSb. If ‘d’ is
‘0’, the result is placed in W. If ‘d’ is ‘1’,
the result is stored back in register ‘f’.
f {,d}
 2013-2015 Microchip Technology Inc.
MOVF
FSR, 0
After Instruction
W = value in FSR register
Z = 1
LSRF
register f
MOVF f,d
Status Affected:
Example:
0
Move f
C
DS40001723D-page 253
PIC12(L)F1571/2
MOVIW
Move INDFn to W
MOVLP
Syntax:
[ label ] MOVIW ++FSRn
[ label ] MOVIW --FSRn
[ label ] MOVIW FSRn++
[ label ] MOVIW FSRn-[ label ] MOVIW k[FSRn]
Syntax:
[ label ] MOVLP k
Operands:
0  k  127
Operation:
k  PCLATH
Status Affected:
None
Operands:
n  [0,1]
mm  [00,01, 10, 11]
-32  k  31
Description:
The 7-bit literal ‘k’ is loaded into the
PCLATH register.
Operation:
INDFn  W
Effective address is determined by
• FSR + 1 (preincrement)
• FSR - 1 (predecrement)
• FSR + k (relative offset)
After the Move, the FSR value will be
either:
• FSR + 1 (all increments)
• FSR - 1 (all decrements)
• Unchanged
Status Affected:
MOVLW
Move literal to W
Syntax:
[ label ]
0  k  255
Operation:
k  (W)
Status Affected:
None
Description:
The 8-bit literal ‘k’ is loaded into W register. The “don’t cares” will assemble as
‘0’s.
Words:
1
1
Mode
Syntax
mm
Cycles:
Preincrement
++FSRn
00
Example:
--FSRn
01
Postincrement
FSRn++
10
Postdecrement
FSRn--
11
Description:
This instruction is used to move data
between W and one of the indirect
registers (INDFn). Before/after this
move, the pointer (FSRn) is updated by
pre/post incrementing/decrementing it.
Note: The INDFn registers are not
physical registers. Any instruction that
accesses an INDFn register actually
accesses the register at the address
specified by the FSRn.
FSRn is limited to the range 0000h FFFFh. Incrementing/decrementing it
beyond these bounds will cause it to
wraparound.
MOVLB
MOVLW k
Operands:
Z
Predecrement
Move literal to PCLATH
MOVLW
0x5A
After Instruction
W =
MOVWF
Move W to f
Syntax:
[ label ]
MOVWF
Operands:
0  f  127
Operation:
(W)  (f)
0x5A
f
Status Affected:
None
Description:
Move data from W register to register
‘f’.
Words:
1
Cycles:
1
Example:
MOVWF
OPTION_REG
Before Instruction
OPTION_REG =
W
=
After Instruction
OPTION_REG =
W
=
0xFF
0x4F
0x4F
0x4F
Move literal to BSR
Syntax:
[ label ] MOVLB k
Operands:
0  k  31
Operation:
k  BSR
Status Affected:
None
Description:
The 5-bit literal ‘k’ is loaded into the
Bank Select Register (BSR).
DS40001723D-page 254
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
MOVWI
Move W to INDFn
Syntax:
[ label ] MOVWI ++FSRn
[ label ] MOVWI --FSRn
[ label ] MOVWI FSRn++
[ label ] MOVWI FSRn-[ label ] MOVWI k[FSRn]
Operands:
Operation:
n  [0,1]
mm  [00,01, 10, 11]
-32  k  31
W  INDFn
Effective address is determined by
• FSR + 1 (preincrement)
• FSR - 1 (predecrement)
• FSR + k (relative offset)
After the Move, the FSR value will be
either:
• FSR + 1 (all increments)
• FSR - 1 (all decrements)
Unchanged
Status Affected:
None
Mode
Syntax
Preincrement
++FSRn
00
Predecrement
--FSRn
01
Postincrement
FSRn++
10
Postdecrement
FSRn--
11
Description:
This instruction is used to move data
between W and one of the indirect
registers (INDFn). Before/after this
move, the pointer (FSRn) is updated by
pre/post incrementing/decrementing it.
mm
Note: The INDFn registers are not
physical registers. Any instruction that
accesses an INDFn register actually
accesses the register at the address
specified by the FSRn.
NOP
No Operation
Syntax:
[ label ]
Operands:
None
Operation:
No operation
Status Affected:
None
NOP
Description:
No operation.
Words:
1
Cycles:
1
Example:
NOP
OPTION
Load OPTION_REG Register
with W
Syntax:
[ label ] OPTION
Operands:
None
Operation:
(W)  OPTION_REG
Status Affected:
None
Description:
Move data from W register to
OPTION_REG register.
RESET
Software Reset
Syntax:
[ label ] RESET
Operands:
None
Operation:
Execute a device Reset. Resets the
nRI flag of the PCON register.
Status Affected:
None
Description:
This instruction provides a way to
execute a hardware Reset by software.
FSRn is limited to the range 0000h FFFFh. Incrementing/decrementing it
beyond these bounds will cause it to
wraparound.
The increment/decrement operation on
FSRn WILL NOT affect any Status bits.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 255
PIC12(L)F1571/2
RETFIE
Return from Interrupt
RETURN
Return from Subroutine
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
None
Operands:
None
Operation:
TOS  PC,
1  GIE
Operation:
TOS  PC
Status Affected:
None
Status Affected:
None
Description:
Description:
Return from Interrupt. Stack is POPed
and Top-of-Stack (TOS) is loaded in
the PC. Interrupts are enabled by
setting Global Interrupt Enable bit,
GIE (INTCON<7>). This is a 2-cycle
instruction.
Return from subroutine. The stack is
POPed and the top of the stack (TOS)
is loaded into the Program Counter.
This is a 2-cycle instruction.
Words:
1
Cycles:
2
Example:
RETFIE
RETURN
RETFIE
After Interrupt
PC =
GIE =
TOS
1
RETLW
Return with literal in W
RLF
Syntax:
[ label ]
Syntax:
[ label ]
0  f  127
d  [0,1]
See description below
RETLW k
Rotate Left f through Carry
RLF
f,d
Operands:
0  k  255
Operands:
Operation:
k  (W);
TOS  PC
Operation:
None
Status Affected:
C
Description:
The W register is loaded with the 8-bit
literal ‘k’. The Program Counter is
loaded from the top of the stack (the
return address). This is a 2-cycle
instruction.
Description:
The contents of register ‘f’ are rotated
one bit to the left through the Carry
flag. If ‘d’ is ‘0’, the result is placed in
the W register. If ‘d’ is ‘1’, the result is
stored back in register ‘f’.
Words:
1
Cycles:
2
Status Affected:
Example:
TABLE
C
CALL TABLE;W contains table
;offset value
•
;W now has table value
•
•
ADDWF PC ;W = offset
RETLW k1 ;Begin table
RETLW k2 ;
•
•
•
RETLW kn ; End of table
Before Instruction
W =
After Instruction
W =
DS40001723D-page 256
Words:
1
Cycles:
1
Example:
RLF
Register f
REG1,0
Before Instruction
REG1
C
After Instruction
REG1
W
C
=
=
1110 0110
0
=
=
=
1110 0110
1100 1100
1
0x07
value of k8
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
RRF
Rotate Right f through Carry
SUBLW
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
0  f  127
d  [0,1]
Operands:
0 k 255
Operation:
k - (W) W)
Operation:
See description below
Status Affected:
C, DC, Z
Status Affected:
C
Description:
Description:
The contents of register ‘f’ are rotated
one bit to the right through the Carry
flag. If ‘d’ is ‘0’, the result is placed in
the W register. If ‘d’ is ‘1’, the result is
placed back in register ‘f’.
The W register is subtracted (2’s complement method) from the 8-bit literal
‘k’. The result is placed in the W register.
RRF f,d
C
Register f
Subtract W from literal
SUBLW k
C=0
Wk
C=1
Wk
DC = 0
W<3:0>  k<3:0>
DC = 1
W<3:0>  k<3:0>
SLEEP
Enter Sleep mode
SUBWF
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
0 f 127
d  [0,1]
Operation:
(f) - (W) destination)
SLEEP
Operands:
None
Operation:
00h  WDT,
0  WDT prescaler,
1  TO,
0  PD
Status Affected:
TO, PD
Description:
The power-down Status bit, PD is
cleared. Time-out Status bit, TO is
set. Watchdog Timer and its prescaler are cleared.
The processor is put into Sleep mode
with the oscillator stopped.
SUBWF f,d
Status Affected:
C, DC, Z
Description:
Subtract (2’s complement method) W
register from register ‘f’. If ‘d’ is ‘0’, the
result is stored in the W
register. If ‘d’ is ‘1’, the result is stored
back in register ‘f.
SUBWFB
 2013-2015 Microchip Technology Inc.
Subtract W from f
C=0
Wf
C=1
Wf
DC = 0
W<3:0>  f<3:0>
DC = 1
W<3:0>  f<3:0>
Subtract W from f with Borrow
Syntax:
SUBWFB
Operands:
0  f  127
d  [0,1]
f {,d}
Operation:
(f) – (W) – (B) dest
Status Affected:
C, DC, Z
Description:
Subtract W and the BORROW flag
(CARRY) from register ‘f’ (2’s complement method). If ‘d’ is ‘0’, the result is
stored in W. If ‘d’ is ‘1’, the result is
stored back in register ‘f’.
DS40001723D-page 257
PIC12(L)F1571/2
SWAPF
Swap Nibbles in f
XORLW
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
0  f  127
d  [0,1]
Operands:
0 k 255
(f<3:0>)  (destination<7:4>),
(f<7:4>)  (destination<3:0>)
Operation:
(W) .XOR. k W)
Operation:
Status Affected:
Z
Status Affected:
None
Description:
Description:
The upper and lower nibbles of register ‘f’ are exchanged. If ‘d’ is ‘0’, the
result is placed in the W register. If ‘d’
is ‘1’, the result is placed in register ‘f’.
The contents of the W register are
XOR’ed with the 8-bit
literal ‘k’. The result is placed in the
W register.
TRIS
Load TRIS Register with W
XORWF
Syntax:
[ label ] TRIS f
Syntax:
[ label ]
Operands:
0  f  127
d  [0,1]
Operation:
(W) .XOR. (f) destination)
SWAPF f,d
Operands:
5f7
Operation:
(W)  TRIS register ‘f’
Status Affected:
None
Description:
Move data from W register to TRIS
register.
When ‘f’ = 5, TRISA is loaded.
When ‘f’ = 6, TRISB is loaded.
When ‘f’ = 7, TRISC is loaded.
DS40001723D-page 258
Exclusive OR literal with W
XORLW k
Exclusive OR W with f
XORWF
f,d
Status Affected:
Z
Description:
Exclusive OR the contents of the W
register with register ‘f’. If ‘d’ is ‘0’, the
result is stored in the W register. If ‘d’
is ‘1’, the result is stored back in register ‘f’.
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
26.0
ELECTRICAL SPECIFICATIONS
26.1
Absolute Maximum Ratings(†)
Ambient temperature under bias............................................................................................................ -40°C to +125°C
Storage temperature .............................................................................................................................. -65°C to +150°C
Voltage on pins with respect to VSS:
on VDD pin
PIC12F1571/2 ................................................................................................................. -0.3V to +6.5V
PIC12LF1571/2 ............................................................................................................... -0.3V to +4.0V
on MCLR pin ................................................................................................................................. -0.3V to +9.0V
on all other pins .................................................................................................................. -0.3V to (VDD + 0.3V)
Maximum current:
on VSS pin(1)
-40°C  TA  +85°C .................................................................................................................... 250 mA
+85°C  TA  +125°C ................................................................................................................... 85 mA
on VDD pin(1)
-40°C  TA  +85°C .................................................................................................................... 250 mA
+85°C  TA  +125°C ................................................................................................................... 85 mA
Sunk by any standard I/O pin ..................................................................................................................... 50 mA
Sourced by any standard I/O pin ................................................................................................................ 50 mA
Clamp current, IK (VPIN < 0 or VPIN > VDD) ......................................................................................................... 20 mA
Total power dissipation(2) .....................................................................................................................................800 mW
Note 1:
2:
Maximum current rating requires even load distribution across I/O pins. Maximum current rating may be
limited by the device package power dissipation characterizations, see Table 26-6: “Thermal
Characteristics” to calculate device specifications.
Power dissipation is calculated as follows: PDIS = VDD x {IDD –  IOH} +  {(VDD – VOH) x IOH} + (VOl x IOL).
† NOTICE: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the
device. This is a stress rating only and functional operation of the device at those or any other conditions above those
indicated in the operation listings of this specification is not implied. Exposure above maximum rating conditions for
extended periods may affect device reliability.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 259
PIC12(L)F1571/2
26.2
Standard Operating Conditions
The standard operating conditions for any device are defined as:
Operating Voltage:
Operating Temperature:
VDDMIN VDD VDDMAX
TA_MIN TA TA_MAX
VDD — Operating Supply Voltage(1)
PIC12LF1571/2
VDDMIN (FOSC  16 MHz) ............................................................................................................... +1.8V
VDDMIN (FOSC  32 MHz) ............................................................................................................... +2.5V
VDDMAX .......................................................................................................................................... +3.6V
PIC12F1571/2
VDDMIN (FOSC  16 MHz) ............................................................................................................... +2.3V
VDDMIN (FOSC  32 MHz) ............................................................................................................... +2.5V
VDDMAX .......................................................................................................................................... +5.5V
TA — Operating Ambient Temperature Range
Industrial Temperature
TA_MIN ............................................................................................................................................ -40°C
TA_MAX .......................................................................................................................................... +85°C
Extended Temperature
TA_MIN ............................................................................................................................................ -40°C
TA_MAX ........................................................................................................................................ +125°C
Note 1:
See Parameter D001, DS Characteristics: Supply Voltage.
DS40001723D-page 260
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
FIGURE 26-1:
VOLTAGE FREQUENCY GRAPH, -40°C  TA +125°C, PIC12F1571/2 ONLY
Rev. 10-000130B
9/19/2013
VDD (V)
5.5
2.5
2.3
0
16
32
Frequency (MHz)
Note 1: The shaded region indicates the permissible combinations of voltage and frequency.
2: Refer to Table 26-7 for each Oscillator mode’s supported frequencies.
FIGURE 26-2:
VOLTAGE FREQUENCY GRAPH, -40°C  TA +125°C, PIC12LF1571/2 ONLY
Rev. 10-000131B
9/19/2013
VDD (V)
3.6
2.5
1.8
0
16
32
Frequency (MHz)
Note 1: The shaded region indicates the permissible combinations of voltage and frequency.
2: Refer to Table 26-7 for each Oscillator mode’s supported frequencies.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 261
PIC12(L)F1571/2
26.3
DC Characteristics
TABLE 26-1:
SUPPLY VOLTAGE
PIC12LF1571/2
Standard Operating Conditions (unless otherwise stated)
PIC12F1571/2
Param.
No.
D001
Sym.
VDD
Characteristic
Min.
Typ†
Max.
Units
VDDMIN
1.8
2.5
—
—
VDDMAX
3.6
3.6
V
V
FOSC  16 MHz
FOSC  32 MHz (Note 3)
2.3
2.5
—
—
5.5
5.5
V
V
FOSC  16 MHz
FOSC  32 MHz (Note 3)
1.5
—
—
V
Device in Sleep mode
1.7
—
—
V
Device in Sleep mode
—
1.6
—
V
—
1.6
—
V
—
0.8
—
V
Supply Voltage
D001
D002*
VDR
RAM Data Retention Voltage(1)
D002*
D002A* VPOR
Power-on Reset Release Voltage(2)
D002A*
D002B* VPORR*
Conditions
Power-on Reset Rearm Voltage(2)
D002B*
—
1.5
—
V
D003
VFVR
Fixed Voltage Reference Voltage
—
1.024
—
V
-40°C  TA  +85°C
D003A
VADFVR
FVR Gain Voltage Accuracy for
ADC
-4
—
+4
%
1x VFVR, ADFVR = 01, VDD 2.5V
2x VFVR, ADFVR = 10, VDD 2.5V
4x VFVR, ADFVR = 11, VDD 4.75V
D003B
VCDAFVR FVR Gain Voltage Accuracy for
Comparator
-4
—
+4
%
1x VFVR, CDAFVR = 01, VDD 2.5V
2x VFVR, CDAFVR = 10, VDD 2.5V
4x VFVR, CDAFVR = 11, VDD 4.75V
D004*
SVDD
0.05
—
—
V/ms
VDD Rise Rate(2)
Ensures that the Power-on Reset
signal is released properly
*
†
These parameters are characterized but not tested.
Data in “Typ” column is at 3.0V, +25°C unless otherwise stated. These parameters are for design guidance only and are
not tested.
Note 1: This is the limit to which VDD can be lowered in Sleep mode without losing RAM data.
2: See Figure 26-3, POR and POR Rearm with Slow Rising VDD.
3: PLL required for 32 MHz operation.
DS40001723D-page 262
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
FIGURE 26-3:
POR AND POR REARM WITH SLOW RISING VDD
VDD
VPOR
VPORR
SVDD
VSS
NPOR(1)
POR Rearm
VSS
TVLOW(3)
Note 1:
2:
3:
TPOR(2)
When NPOR is low, the device is held in Reset.
TPOR: 1 s typical.
TVLOW: 2.7 s typical.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 263
PIC12(L)F1571/2
TABLE 26-2:
SUPPLY CURRENT (IDD)(1,2)
PIC12LF1571/2
Standard Operating Conditions (unless otherwise stated)
PIC12F1571/2
Param.
No.
Device
Characteristics
D013
D013
D014
D014
D015
D015
D016
D016
Min.
Typ†
Max.
Units
—
35
44
—
60
—
Conditions
VDD
Note
A
1.8
69
A
3.0
FOSC = 1 MHz,
External Clock (ECM),
Medium Power mode
68
93
A
2.3
—
91
120
A
3.0
—
131
160
A
5.0
—
116
132
A
1.8
—
203
233
A
3.0
—
174
221
A
2.3
—
234
286
A
3.0
—
299
374
A
5.0
—
5.5
11
A
1.8
—
7.3
12
A
3.0
—
13
21
A
2.3
—
15
24
A
3.0
—
17
25
A
5.0
—
111
151
A
1.8
—
133
176
A
3.0
—
144
209
A
2.3
—
162
237
A
3.0
—
216
288
A
5.0
D017*
—
0.5
0.6
mA
1.8
—
0.7
0.9
mA
3.0
D017*
—
0.6
0.8
mA
2.3
—
0.8
0.9
mA
3.0
—
0.9
1.0
mA
5.0
D018
D018
*
†
Note 1:
2:
3:
—
0.7
0.8
mA
1.8
—
1.1
1.2
mA
3.0
—
0.9
1.1
mA
2.3
—
1.1
1.3
mA
3.0
—
1.3
1.5
mA
5.0
FOSC = 1 MHz,
External Clock (ECM),
Medium Power mode
FOSC = 4 MHz,
External Clock (ECM),
Medium Power mode
FOSC = 4 MHz,
External Clock (ECM),
Medium Power mode
FOSC = 31 kHz,
LFINTOSC,
-40°C  TA  +85°C
FOSC = 31 kHz,
LFINTOSC,
-40°C  TA  +85°C
FOSC = 500 kHz,
MFINTOSC
FOSC = 500 kHz,
MFINTOSC
FOSC = 8 MHz,
HFINTOSC
FOSC = 8 MHz,
HFINTOSC
FOSC = 16 MHz,
HFINTOSC
FOSC = 16 MHz,
HFINTOSC
These parameters are characterized but not tested.
Data in “Typ” column is at 3.0V, +25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
The test conditions for all IDD measurements in active operation mode are: CLKIN = external square wave,
from rail-to-rail; all I/O pins tri-stated, pulled to VSS; MCLR = VDD; WDT disabled.
The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O
pin loading and switching rate, oscillator type, internal code execution pattern and temperature, also have
an impact on the current consumption.
PLL required for 32 MHz operation.
DS40001723D-page 264
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
TABLE 26-2:
SUPPLY CURRENT (IDD)(1,2) (CONTINUED)
PIC12LF1571/2
Standard Operating Conditions (unless otherwise stated)
PIC12F1571/2
Param.
No.
Device
Characteristics
Conditions
Min.
Typ†
Max.
Units
D018A*
—
2
2.4
mA
3.0
FOSC = 32 MHz,
HFINTOSC (Note 3)
D018A*
—
2.1
2.5
mA
3.0
—
2.2
2.6
mA
5.0
FOSC = 32 MHz,
HFINTOSC (Note 3)
D019A
—
1.7
1.9
mA
3.0
FOSC = 32 MHz,
External Clock (ECH),
High-Power mode (Note 3)
D019A
—
1.8
2
mA
3.0
—
1.9
2.3
mA
5.0
FOSC = 32 MHz,
External Clock (ECH),
High-Power mode (Note 3)
—
2.2
5.9
A
1.8
—
4.3
8.3
A
3.0
—
12
20
A
2.3
—
15
25
A
3.0
—
17
26
A
5.0
—
18
25
A
1.8
—
30
38
A
3.0
—
29
40
A
2.3
—
37
51
A
3.0
—
42
53
A
5.0
D019B
D019B
D019C
D019C
*
†
Note 1:
2:
3:
VDD
Note
FOSC = 32 kHz,
External Clock (ECL),
Low-Power mode
FOSC = 32 kHz,
External Clock (ECL),
Low-Power mode
FOSC = 500 kHz,
External Clock (ECL),
Low-Power mode
FOSC = 500 kHz,
External Clock (ECL),
Low-Power mode
These parameters are characterized but not tested.
Data in “Typ” column is at 3.0V, +25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
The test conditions for all IDD measurements in active operation mode are: CLKIN = external square wave,
from rail-to-rail; all I/O pins tri-stated, pulled to VSS; MCLR = VDD; WDT disabled.
The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O
pin loading and switching rate, oscillator type, internal code execution pattern and temperature, also have
an impact on the current consumption.
PLL required for 32 MHz operation.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 265
PIC12(L)F1571/2
TABLE 26-3:
POWER-DOWN CURRENTS (IPD)(1,2)
PIC12LF1571/2
Operating Conditions (unless otherwise stated)
Low-Power Sleep Mode
PIC12F1571/2
Low-Power Sleep Mode, VREGPM = 1
Param.
No.
D022
Device Characteristics
Base IPD
D022
Base IPD
D022A
Base IPD
D023
D023
Conditions
Min.
Typ†
Max.
+85°C
Max.
+125°C
Units
—
0.020
0.6
2.6
A
1.8
—
0.025
0.8
2.9
A
3.0
—
0.2
0.9
2.8
A
2.3
—
0.3
3.0
3.8
A
3.0
—
0.4
3.6
4.5
A
5.0
—
9
14
15
A
2.3
—
11
19
21
A
3.0
—
12
21
22
A
5.0
WDT, BOR and FVR disabled,
all peripherals inactive,
Normal Power Sleep mode,
VREGPM = 0
—
0.3
0.8
2.9
A
1.8
WDT Current
—
0.5
1.1
3.5
A
3.0
—
0.5
1.7
4.1
A
2.3
—
0.6
1.9
4.4
A
3.0
VDD
Note
WDT, BOR and FVR disabled,
all peripherals inactive,
VREGPM = 1
WDT, BOR and FVR disabled,
all peripherals inactive,
Low-Power Sleep mode,
VREGPM = 1
WDT Current
—
0.7
2.1
4.7
A
5.0
D023A
—
13
18
20
A
1.8
—
22
28
29
A
3.0
D023A
—
16
24
25
A
2.3
—
19
30
31
A
3.0
—
20
33
35
A
5.0
D024
—
6.5
9
11
A
3.0
BOR Current
D024
—
7.0
10
11
A
3.0
BOR Current
—
8.0
12
13
A
5.0
D24A
—
0.2
2
4
A
3.0
LPBOR Current
D24A
—
0.4
2
4
A
3.0
LPBOR Current
—
0.5
3
5
A
5.0
—
0.03
0.7
2.7
A
1.8
—
0.04
0.8
3
A
3.0
—
0.2
1.3
3.8
A
2.3
—
0.3
1.4
3.9
A
3.0
D026
D026
—
0.4
1.5
4
A
5.0
D026A*
—
250
—
—
A
1.8
—
250
—
—
A
3.0
D026A*
—
280
—
—
A
2.3
—
280
—
—
A
3.0
—
280
—
—
A
5.0
*
†
Note 1:
2:
3:
FVR Current
FVR Current
ADC Current (Note 3),
No conversion in progress
ADC Current (Note 3),
No conversion in progress
ADC Current (Note 3),
Conversion in progress
ADC Current (Note 3),
Conversion in progress
These parameters are characterized but not tested.
Data in “Typ” column is at 3.0V, +25°C unless otherwise stated. These parameters are for design guidance only and are
not tested.
The peripheral  current can be determined by subtracting the base IPD current from this limit. Max. values should be
used when calculating total current consumption.
The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is measured with
the part in Sleep mode, with all I/O pins in high-impedance state and tied to VSS.
ADC clock source is FRC.
DS40001723D-page 266
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
TABLE 26-3:
POWER-DOWN CURRENTS (IPD)(1,2) (CONTINUED)
PIC12LF1571/2
Operating Conditions (unless otherwise stated)
Low-Power Sleep Mode
PIC12F1571/2
Low-Power Sleep Mode, VREGPM = 1
Param.
No.
Conditions
Min.
Typ†
Max.
+85°C
Max.
+125°C
Units
D027
—
4
7
9
A
—
4.2
8
10
A
3.0
D027
—
13
20
21
A
2.3
—
14
23
25
A
3.0
—
16
24
26
A
5.0
—
20
35
36
A
1.8
—
21
36
38
A
3.0
—
28
47
48
A
2.3
—
29
51
52
A
3.0
—
31
52
53
A
5.0
Device Characteristics
D028A
D028A
*
†
Note 1:
2:
3:
Note
VDD
1.8
Comparator,
CxSP = 0
Comparator,
CxSP = 0
Comparator,
Normal Power, CxSP = 1
(Note 1)
Comparator,
Normal Power, CxSP = 1,
VREGPM = 1 (Note 1)
These parameters are characterized but not tested.
Data in “Typ” column is at 3.0V, +25°C unless otherwise stated. These parameters are for design guidance only and are
not tested.
The peripheral  current can be determined by subtracting the base IPD current from this limit. Max. values should be
used when calculating total current consumption.
The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is measured with
the part in Sleep mode, with all I/O pins in high-impedance state and tied to VSS.
ADC clock source is FRC.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 267
PIC12(L)F1571/2
TABLE 26-4:
I/O PORTS
Standard Operating Conditions (unless otherwise stated)
Param.
No.
Sym.
VIL
Characteristic
Min.
Typ†
Max.
Units
—
—
Conditions
—
0.8
V
4.5V  VDD  5.5V
—
0.15 VDD
V
1.8V  VDD  4.5V
2.0V  VDD  5.5V
Input Low Voltage
I/O Ports:
D030
with TTL Buffer
D030A
D031
D032
with Schmitt Trigger Buffer
—
—
0.2 VDD
V
with I2C Levels
—
—
0.3 VDD
V
with SMbus Levels
—
—
0.8
V
—
—
0.2 VDD
V
MCLR
VIH
2.7V  VDD  5.5V
Input High Voltage
I/O Ports:
D040
2.0
—
—
V
4.5V  VDD 5.5V
0.25 VDD + 0.8
—
—
V
1.8V  VDD  4.5V
with Schmitt Trigger Buffer
0.8 VDD
—
—
V
2.0V  VDD  5.5V
with I2C Levels
0.7 VDD
—
—
V
with TTL Buffer
D040A
D041
with SMbus Levels
D042
MCLR
IIL
D060
MCLR(2)
IPUR
D080
D090
V
—
V
—
±5
± 125
nA
VSS  VPIN  VDD,
Pin at high-impedance, +85°C
—
±5
± 1000
nA
VSS  VPIN  VDD,
Pin at high-impedance, +125°C
—
± 50
± 200
nA
VSS  VPIN  VDD,
Pin at high-impedance, +85°C
25
100
200
A
VDD = 3.3V, VPIN = VSS
25
140
300
A
VDD = 5.0V, VPIN = VSS
—
—
0.6
V
IOL = 8 mA, VDD = 5V
IOL = 6 mA, VDD = 3.3V
IOL = 1.8 mA, VDD = 1.8V
VDD – 0.7
—
—
V
IOH = 3.5 mA, VDD = 5V
IOH = 3 mA, VDD = 3.3V
IOH = 1 mA, VDD = 1.8V
50
pF
Output Low Voltage
I/O Ports
VOH
—
—
Weak Pull-up Current
D070*
VOL
—
Input Leakage Current(1)
I/O Ports
D061
2.7V  VDD  5.5V
2.1
0.8 VDD
Output High Voltage
I/O Ports
Capacitive Loading Specifications on Output Pins
D101A* CIO
All I/O Pins
—
—
*
†
These parameters are characterized but not tested.
Data in “Typ” column is at 3.0V, +25°C unless otherwise stated. These parameters are for design guidance only and are
not tested.
Note 1: Negative current is defined as current sourced by the pin.
2: The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified levels represent
normal operating conditions. Higher leakage current may be measured at different input voltages.
DS40001723D-page 268
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
TABLE 26-5:
MEMORY PROGRAMMING SPECIFICATIONS
Standard Operating Conditions (unless otherwise stated)
Param.
No.
Sym.
Characteristic
Min.
Typ†
Max.
Units
Conditions
Program Memory
Programming Specifications
D110
VIHH
Voltage on MCLR/VPP Pin
8.0
—
9.0
V
D111
IDDP
Supply Current during
Programming
—
—
10
mA
D112
VBE
VDD for Bulk Erase
2.7
—
VDDMAX
V
D113
VPEW
VDD for Write or Row Erase
VDDMIN
—
VDDMAX
V
D114
IPPPGM Current on MCLR/VPP during
Erase/Write
—
1.0
—
mA
D115
IDDPGM Current on VDD during
Erase/Write
—
5.0
—
mA
D121
EP
Cell Endurance
10K
—
—
E/W
(Note 2)
Program Flash Memory
-40C  TA  +85C
(Note 1)
D122
VPRW
VDD for Read/Write
VDDMIN
—
VDDMAX
V
D123
TIW
Self-Timed Write Cycle Time
—
2
2.5
ms
D124
TRETD
Characteristic Retention
—
40
—
Year
Provided no other
specifications are violated
D125
EHEFC
High-Endurance Flash Cell
100K
—
—
E/W
0C  TA  +60°C, lower
byte last 128 addresses
† Data in “Typ” column is at 3.0V, +25°C unless otherwise stated. These parameters are for design
guidance only and are not tested.
Note 1: Self-write and block erase.
2: Required only if single-supply programming is disabled.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 269
PIC12(L)F1571/2
TABLE 26-6:
THERMAL CHARACTERISTICS
Standard Operating Conditions (unless otherwise stated)
Param.
No.
TH01
TH02
Sym.
Characteristic
JA
Thermal Resistance Junction to Ambient
JC
TH03
TJMAX
TH04
PD
TH05
Thermal Resistance Junction to Case
Maximum Junction Temperature
Power Dissipation
PINTERNAL Internal Power Dissipation
Typ.
Units
Conditions
56.7
C/W
8-pin DFN 3x3 mm package
89.3
C/W
8-pin PDIP package
149.5
C/W
8-pin SOIC package
39.4
C/W
8-pin UDFN 3x3 mm package
9.0
C/W
8-pin DFN 3x3 mm package
43.1
C/W
8-pin PDIP package
39.9
C/W
8-pin SOIC package
40.3
C/W
8-pin UDFN 3x3 mm package
150
C
—
W
PD = PINTERNAL + PI/O
—
W
PINTERNAL = IDD x VDD(1)
TH06
PI/O
I/O Power Dissipation
—
W
PI/O =  (IOL * VOL) +  (IOH * (VDD – VOH))
TH07
PDER
Derated Power
—
W
PDER = PDMAX (TJ – TA)/JA(2)
Note 1: IDD is current to run the chip alone without driving any load on the output pins.
2: TA = Ambient Temperature; TJ = Junction Temperature.
DS40001723D-page 270
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
26.4
AC Characteristics
Timing Parameter Symbology has been created with one of the following formats:
1. TppS2ppS
2. TppS
T
F
Frequency
Lowercase letters (pp) and their meanings:
pp
cc
CCP1
ck
CLKOUT
cs
CS
di
SDIx
do
SDO
dt
Data in
io
I/O PORT
mc
MCLR
Uppercase letters and their meanings:
S
F
Fall
H
High
I
Invalid (High-impedance)
L
Low
FIGURE 26-4:
T
Time
osc
rd
rw
sc
ss
t0
t1
wr
CLKIN
RD
RD or WR
SCKx
SS
T0CKI
T1CKI
WR
P
R
V
Z
Period
Rise
Valid
High-impedance
LOAD CONDITIONS
Rev. 10-000133A
8/1/2013
Load Condition
Pin
CL
VSS
Legend: CL=50 pF for all pins
 2013-2015 Microchip Technology Inc.
DS40001723D-page 271
PIC12(L)F1571/2
FIGURE 26-5:
CLOCK TIMING
Q4
Q1
Q2
Q3
Q4
Q1
CLKIN
OS02
OS04
OS04
OS03
CLKOUT
(CLKOUT Mode)
Note 1:
See Table 26-10.
TABLE 26-7:
CLOCK OSCILLATOR TIMING REQUIREMENTS
Standard Operating Conditions (unless otherwise stated)
Param.
No.
OS01
Sym.
FOSC
Characteristic
External CLKIN Frequency(1)
Min.
Typ†
Max.
Units
Conditions
DC
—
0.5
MHz
External Clock (ECL)
DC
—
4
MHz
External Clock (ECM)
External Clock (ECH)
DC
—
20
MHz
OS02
TOSC
External CLKIN Period(1)
50
—

ns
External Clock (EC)
OS03
TCY
Instruction Cycle Time(1)
200
TCY
DC
ns
TCY = 4/FOSC
*
†
These parameters are characterized but not tested.
Data in “Typ” column is at 3.0V, +25°C unless otherwise stated. These parameters are for design guidance only and are
not tested.
Note 1: Instruction cycle period (TCY) equals four times the input oscillator time base period. All specified values are based on
characterization data for that particular oscillator type under standard operating conditions with the device executing code.
Exceeding these specified limits may result in an unstable oscillator operation and/or higher than expected current consumption. All devices are tested to operate at “min” values with an external clock applied to the CLKIN pin. When an
external clock input is used, the “max” cycle time limit is “DC” (no clock) for all devices.
DS40001723D-page 272
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
TABLE 26-8:
OSCILLATOR PARAMETERS
Standard Operating Conditions (unless otherwise stated)
Param.
No.
Sym.
Characteristic
Freq.
Tolerance
Min.
Typ†
Max.
Units
OS08
HFOSC
Internal Calibrated HFINTOSC
Frequency(1)
±2%
—
16.0
—
MHz
OS09
LFOSC
Internal LFINTOSC Frequency
—
—
31
—
kHz
OS10*
TWARM
HFINTOSC
Wake-up from Sleep Start-up Time
—
—
5
15
s
LFINTOSC
Wake-up from Sleep Start-up Time
—
—
0.5
—
ms
Conditions
VDD = 3.0V, TA = 25°C
(Note 2)
*
†
These parameters are characterized but not tested.
Data in “Typ” column is at 3.0V, +25°C unless otherwise stated. These parameters are for design guidance only and are
not tested.
Note 1: To ensure these oscillator frequency tolerances, VDD and VSS must be capacitively decoupled as close to the device as
possible. 0.1 F and 0.01 F values in parallel are recommended.
2: See Figure 26-6: “HFINTOSC Frequency Accuracy Over Device VDD and Temperature.
HFINTOSC FREQUENCY ACCURACY OVER DEVICE VDD AND TEMPERATURE
FIGURE 26-6:
+125
± 5%
Temperature (°C)
+85
± 3%
+60
± 2%
+25
0
± 5%
-40
1.8
2.5
2.0
3.0
3.5
4.0
4.5
5.0
5.5
VDD (V)
TABLE 26-9:
Param
No.
Sym.
PLL CLOCK TIMING SPECIFICATIONS (VDD = 2.7V TO 5.5V)
Characteristic
Min.
Typ†
Max.
Units
F10
F11
FOSC Oscillator Frequency Range
FSYS On-Chip VCO System Frequency
4
16
—
—
8
32
MHz
MHz
F12
TRC
PLL Start-up Time (Lock Time)
—
—
2
ms
CLK
CLKOUT Stability (Jitter)
-0.25%
—
+0.25%
%
F13*
Conditions
* These parameters are characterized but not tested.
† Data in “Typ” column is at 3V, +25C unless otherwise stated. These parameters are for design guidance
only and are not tested.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 273
PIC12(L)F1571/2
FIGURE 26-7:
CLKOUT AND I/O TIMING
Cycle
Write
Fetch
Read
Execute
Q4
Q1
Q2
Q3
FOSC
OS12
OS11
OS20
OS21
CLKOUT
OS19
OS18
OS16
OS13
OS17
I/O pin
(Input)
OS14
OS15
I/O pin
(Output)
New Value
Old Value
OS18, OS19
TABLE 26-10: CLKOUT AND I/O TIMING PARAMETERS
Standard Operating Conditions (unless otherwise stated)
Param.
No.
Sym.
Characteristic
Min.
Typ†
Max.
Units
Conditions
OS11
TosH2ckL
FOSC to CLKOUT(1)
—
—
70
ns
3.3V  VDD 5.0V
OS12
TosH2ckH
FOSC to CLKOUT(1)
—
—
72
ns
3.3V  VDD 5.0V
OS13
TckL2ioV
CLKOUT to Port Out Valid(1)
—
—
20
ns
OS14
TioV2ckH
Port Input Valid Before CLKOUT(1)
TOSC + 200 ns
—
—
ns
OS15
TosH2ioV
Fosc (Q1 cycle) to Port Out Valid
—
50
70*
ns
3.3V  VDD 5.0V
OS16
TosH2ioI
Fosc (Q2 cycle) to Port Input Invalid
(I/O in setup time)
50
—
—
ns
3.3V  VDD 5.0V
OS17
TioV2osH
Port Input Valid to Fosc(Q2 cycle)
(I/O in setup time)
20
—
—
ns
OS18*
TioR
Port Output Rise Time
—
—
40
15
72
32
ns
VDD = 1.8V,
3.3V  VDD 5.0V
OS19*
TioF
Port Output Fall Time
—
—
28
15
55
30
ns
VDD = 1.8V,
3.3V  VDD 5.0V
OS20*
Tinp
INT Pin Input High or Low Time
25
—
—
ns
OS21*
Tioc
Interrupt-On-Change New Input Level Time
25
—
—
ns
* These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, +25C unless otherwise stated.
Note 1: Measurements are taken in EXTRC mode where CLKOUT output is 4 x TOSC.
DS40001723D-page 274
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
FIGURE 26-8:
RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND POWER-UP
TIMER TIMING
VDD
MCLR
30
Internal
POR
PWRT
Time-out
33
32
OSC
Start-up Time
Internal Reset(1)
Watchdog Timer
Reset(1)
34
31
34
I/O Pins
Note 1: Asserted low.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 275
PIC12(L)F1571/2
TABLE 26-11: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER, POWER-UP TIMER
AND BROWN-OUT RESET PARAMETERS
Standard Operating Conditions (unless otherwise stated)
Param.
No.
Sym.
Characteristic
Min.
Typ†
Max.
Units
Conditions
2
—
—
s
10
16
27
ms
Oscillator Start-up Timer Period(1)
—
1024
—
TOSC
TPWRT
Power-up Timer Period
40
65
140
ms
34*
TIOZ
I/O High-Impedance from MCLR Low
or Watchdog Timer Reset
—
—
2.0
s
35
VBOR
Brown-out Reset Voltage(2)
2.55
2.35
1.80
2.70
2.45
1.90
2.85
2.58
2.05
V
V
V
36*
VHYST
Brown-out Reset Hysteresis
0
25
60
mV
37*
TBORDC Brown-out Reset DC Response Time
1
16
35
s
VDD  VBOR
38
VLPBOR Low-Power Brown-out Reset Voltage
1.8
2.1
2.5
V
LPBOR = 1
30
TMCL
31
TWDTLP Low-Power Watchdog Timer
Time-out Period
32
TOST
33*
*
†
Note 1:
2:
MCLR Pulse Width (low)
VDD = 3.3V-5V,
1:512 prescaler used
PWRTE = 0
BORV = 0
BORV = 1 (PIC12F1571/2)
BORV = 1 (PIC12LF1571/2)
-40°C  TA  +85°C
These parameters are characterized but not tested.
Data in “Typ” column is at 3.0V, +25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
By design, the Oscillator Start-up Timer (OST) counts the first 1024 cycles, independent of frequency.
To ensure these voltage tolerances, VDD and VSS must be capacitively decoupled as close to the device as
possible. 0.1 F and 0.01 F values in parallel are recommended.
FIGURE 26-9:
BROWN-OUT RESET TIMING AND CHARACTERISTICS
VDD
VBOR and VHYST
VBOR
(Device in Brown-out Reset)
(Device not in Brown-out Reset)
37
Reset
(due to BOR)
DS40001723D-page 276
33
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
FIGURE 26-10:
TIMER0 AND TIMER1 EXTERNAL CLOCK TIMINGS
T0CKI
40
41
42
T1CKI
45
46
49
47
TMR0 or
TMR1
TABLE 26-12: TIMER0 AND TIMER1 EXTERNAL CLOCK REQUIREMENTS
Standard Operating Conditions (unless otherwise stated)
Param.
No.
40*
Sym.
TT0H
Characteristic
T0CKI High Pulse Width
Min.
No Prescaler
With Prescaler
41*
TT0L
T0CKI Low Pulse Width
No Prescaler
With Prescaler
Typ†
Max.
Units
0.5 TCY + 20
—
—
ns
10
—
—
ns
0.5 TCY + 20
—
—
ns
10
—
—
ns
Greater of:
20 or TCY + 40
N
—
—
ns
42*
TT0P
T0CKI Period
45*
TT1H
T1CKI High Synchronous, No Prescaler
Time
Synchronous, with Prescaler
0.5 TCY + 20
—
—
ns
15
—
—
ns
Asynchronous
30
—
—
ns
Synchronous, No Prescaler
0.5 TCY + 20
—
—
ns
Synchronous, with Prescaler
15
—
—
ns
Asynchronous
30
—
—
ns
Greater of:
30 or TCY + 40
N
—
—
ns
TT1L
46*
T1CKI Low
Time
47*
TT1P
T1CKI Input Synchronous
Period
49*
TCKEZTMR1 Delay from External Clock Edge to Timer
Increment
Asynchronous
*
†
60
—
—
ns
2 TOSC
—
7 TOSC
—
Conditions
N = Prescale value
N = Prescale value
Timers in Sync
mode
These parameters are characterized but not tested.
Data in “Typ” column is at 3.0V, +25°C unless otherwise stated. These parameters are for design guidance only and are
not tested.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 277
PIC12(L)F1571/2
TABLE 26-13: ANALOG-TO-DIGITAL CONVERTER (ADC) CHARACTERISTICS(1,2,3)
Operating Conditions (unless otherwise stated)
VDD = 3.0V, TA = +25°C
Param.
Sym.
No.
Characteristic
Min.
Typ†
Max.
AD01
NR
Resolution
—
—
10
AD02
EIL
Integral Error
—
±1
±1.7
AD03
EDL
Differential Error
AD04
EOFF Offset Error
AD05
EGN
AD06
AD07
VAIN
Full-Scale Range
AD08
ZAIN
Recommended Impedance of
Analog Voltage Source
*
†
Note 1:
2:
3:
4:
Units
Conditions
bit
LSb VREF = 3.0V
—
±1
±1
—
±1
±2.5
LSb VREF = 3.0V
LSb No missing codes, VREF = 3.0V
Gain Error
—
±1
±2.0
LSb VREF = 3.0V
VREF Reference Voltage
1.8
—
VDD
V
VSS
—
VREF
V
—
—
10
k
VREF = (VRPOS – VRNEG) (Note 4)
Can go higher if external 0.01 F capacitor is
present on input pin.
These parameters are characterized but not tested.
Data in “Typ” column is at 3.0V, +25°C unless otherwise stated. These parameters are for design guidance only and are
not tested.
Total absolute error includes integral, differential, offset and gain errors.
The ADC conversion result never decreases with an increase in the input voltage and has no missing codes.
See Section 27.0 “DC and AC Characteristics Graphs and Charts” for operating characterization.
ADC VREF is selected by the ADPREF<0> bit.
DS40001723D-page 278
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
FIGURE 26-11:
ADC CONVERSION TIMING (ADC CLOCK FOSC-BASED)
BSF ADCON0, GO
AD133
1 TCY
AD131
Q4
AD130
ADC_clk
9
ADC Data
8
7
6
3
2
1
0
NEW_DATA
OLD_DATA
ADRES
1 TCY
ADIF
GO
Sample
DONE
Sampling Stopped
AD132
FIGURE 26-12:
ADC CONVERSION TIMING (ADC CLOCK FROM FRC)
BSF ADCON0, GO
AD133
1 TCY
AD131
Q4
AD130
ADC_clk
9
ADC Data
8
7
6
OLD_DATA
ADRES
2
1
0
NEW_DATA
1 TCY
ADIF
GO
Sample
3
DONE
AD132
Sampling Stopped
Note 1: If the ADC clock source is selected as FRC, a time of TCY is added before the ADC clock starts; this allows the
SLEEP instruction to be executed.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 279
PIC12(L)F1571/2
TABLE 26-14: ADC CONVERSION REQUIREMENTS
Standard Operating Conditions (unless otherwise stated)
Param.
Sym.
No.
AD130* TAD
AD131 TCNV
Characteristic
Min.
Typ†
Max. Units
Conditions
ADC Clock Period (TADC)
1.0
—
6.0
s
FOSC-based
ADC Internal FRC Oscillator Period (TFRC)
1.0
2.0
6.0
s
ADCS<2:0> = x11 (ADC FRC mode)
Conversion Time
(not including Acquisition Time)(1)
—
11
—
TAD
Set GO/DONE bit to conversion
complete
s
AD132* TACQ Acquisition Time
—
5.0
—
AD133* THCD Holding Capacitor Disconnect Time
—
—
1/2 TAD
1/2 TAD + 1TCY
—
—
FOSC-based,
ADCS<2:0> = x11 (ADC FRC mode)
*
†
These parameters are characterized but not tested.
Data in “Typ” column is at 3.0V, +25°C unless otherwise stated. These parameters are for design guidance only and are
not tested.
Note 1: The ADRES register may be read on the following TCY cycle.
DS40001723D-page 280
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
TABLE 26-15: COMPARATOR SPECIFICATIONS(1)
Operating Conditions (unless otherwise stated)
VDD = 3.0V, TA = +25°C
Param.
No.
CM01
Sym.
Characteristics
VIOFF
Input Offset Voltage
Min.
Typ.
Max.
Units
—
±7.5
±60
mV
Comments
CxSP = 1,
VICM = VDD/2
CM02
VICM
Input Common-Mode Voltage
0
—
VDD
V
CM03
CMRR
Common-Mode Rejection Ration
—
50
—
dB
CM04A
TRESP(2)
Response Time Rising Edge
—
400
800
ns
CxSP = 1
Response Time Falling Edge
—
200
400
ns
CxSP = 1
CM04B
CM04C
Response Time Rising Edge
—
1200
—
ns
CxSP = 0
CM04D
Response Time Falling Edge
—
550
—
ns
CxSP = 0
Comparator Mode Change to
Output Valid
—
—
10
s
—
25
—
mV
CM05*
TMC2OV
CM06
CHYSTER Comparator Hysteresis
*
Note 1:
2:
CxHYS = 1,
CxSP = 1
These parameters are characterized but not tested.
See Section 27.0 “DC and AC Characteristics Graphs and Charts” for operating characterization.
Response time measured with one comparator input at VDD/2, while the other input transitions from
VSS to VDD.
TABLE 26-16: DIGITAL-TO-ANALOG CONVERTER (DAC) SPECIFICATIONS(1)
Operating Conditions (unless otherwise stated)
VDD = 3.0V, TA = +25°C
Param.
No.
Sym.
Characteristics
Min.
Typ.
Max.
Units
—
VDD/32
—
V
DAC01*
CLSB
Step Size
DAC02*
CACC
Absolute Accuracy
—
—
 1/2
LSb
DAC03*
CR
Unit Resistor Value (R)
—
5K
—

CST
Time(2)
—
—
10
s
DAC04*
*
Note 1:
2:
Settling
Comments
These parameters are characterized but not tested.
See Section 27.0 “DC and AC Characteristics Graphs and Charts” for operating characterization.
Settling time measured while DACR<4:0> transitions from ‘0000’ to ‘1111’.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 281
PIC12(L)F1571/2
FIGURE 26-13:
USART SYNCHRONOUS TRANSMISSION (MASTER/SLAVE) TIMING
CK
US121
US121
DT
US122
US120
Note:
Refer to Figure 26-4 for load conditions.
TABLE 26-17: USART SYNCHRONOUS TRANSMISSION REQUIREMENTS
Standard Operating Conditions (unless otherwise stated)
Param.
No.
US120
US121
US122
Symbol
TCKH2DTV
TCKRF
TDTRF
FIGURE 26-14:
Characteristic
Min.
Max.
Units
Conditions
SYNC XMIT (Master and Slave)
Clock High to Data-Out Valid
—
80
ns
3.0V  VDD  5.5V
—
100
ns
1.8V  VDD  5.5V
Clock Out Rise Time and Fall Time
(Master mode)
—
45
ns
3.0V  VDD  5.5V
—
50
ns
1.8V  VDD  5.5V
Data-Out Rise Time and Fall Time
—
45
ns
3.0V  VDD  5.5V
—
50
ns
1.8V  VDD  5.5V
USART SYNCHRONOUS RECEIVE (MASTER/SLAVE) TIMING
CK
US125
DT
US126
Note: Refer to Figure 26-4 for load conditions.
TABLE 26-18: USART SYNCHRONOUS RECEIVE REQUIREMENTS
Standard Operating Conditions (unless otherwise stated)
Param.
No.
Symbol
Characteristic
US125 TDTV2CKL SYNC RCV (Master and Slave)
Data-Hold before CK  (DT hold time)
US126 TCKL2DTL
Data-Hold after CK  (DT hold time)
DS40001723D-page 282
Min.
Max.
Units
10
—
ns
15
—
ns
Conditions
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
27.0
DC AND AC CHARACTERISTICS GRAPHS AND CHARTS
The graphs and tables provided in this section are for design guidance and are not tested.
In some graphs or tables, the data presented is outside specified operating range (i.e., outside specified VDD range).
This is for information only and devices are ensured to operate properly only within the specified range.
Note:
The graphs and tables provided following this note are a statistical summary based on a limited number of
samples and are provided for informational purposes only. The performance characteristics listed herein
are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified
operating range (e.g., outside specified power supply range) and therefore, outside the warranted range.
“Typical” represents the mean of the distribution at +25C. “MAXIMUM”, “Max.”, “MINIMUM” or “Min.”
represents (mean + 3) or (mean – 3) respectively, where  is a standard deviation over each
temperature range.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 283
PIC12(L)F1571/2
FIGURE 27-1:
IDD, EC OSCILLATOR, LOW-POWER MODE, FOSC = 32 kHz, PIC12LF1571/2 ONLY
6.0
5.5
Max.
Max: 85°C + 3ı
Typical: 25°C
5.0
4.5
Typical
IDD (µA)
4.0
3.5
3.0
2.5
2.0
1.5
1.0
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
VDD (V)
IDD, EC OSCILLATOR, LOW-POWER MODE, FOSC = 32 kHz, PIC12F1571/2 ONLY
FIGURE 27-2:
25
Max: 85°C + 3ı
Typical: 25°C
20
Max.
IDD (µA)
Typical
15
10
5
0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
VDD (V)
DS40001723D-page 284
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
FIGURE 27-3:
IDD, EC OSCILLATOR, LOW-POWER MODE, FOSC = 500 kHz, PIC12LF1571/2 ONLY
40
Max: 85°C + 3ı
Typical: 25°C
35
Max.
Typical
IDD (µA)
30
25
20
15
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
VDD (V)
FIGURE 27-4:
IDD, EC OSCILLATOR, LOW-POWER MODE, FOSC = 500 kHz, PIC12F1571/2 ONLY
50
Max.
Max: 85°C + 3ı
Typical: 25°C
45
IDD (µA)
40
Typical
35
30
25
20
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
VDD (V)
 2013-2015 Microchip Technology Inc.
DS40001723D-page 285
PIC12(L)F1571/2
FIGURE 27-5:
IDD TYPICAL, EC OSCILLATOR, MEDIUM POWER MODE, PIC12LF1571/2 ONLY
300
Typical: 25°C
250
4 MHz
IDD (µA)
200
150
100
1 MHz
50
0
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
VDD (V)
IDD MAXIMUM, EC OSCILLATOR, MEDIUM POWER MODE, PIC12LF1571/2 ONLY
FIGURE 27-6:
300
4 MHz
Max: 85°C + 3ı
250
IDD (µA)
200
150
100
1 MHz
50
0
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
VDD (V)
DS40001723D-page 286
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
FIGURE 27-7:
IDD TYPICAL, EC OSCILLATOR, MEDIUM POWER MODE, PIC12F1571/2 ONLY
350
4 MHz
Typical: 25°C
300
IDD (µA)
250
200
150
1 MHz
100
50
0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
VDD (V)
FIGURE 27-8:
IDD MAXIMUM, EC OSCILLATOR, MEDIUM POWER MODE, PIC12F1571/2 ONLY
400
350
4 MHz
Max: 85°C + 3ı
300
IDD (µA)
250
200
1 MHz
150
100
50
0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
VDD (V)
 2013-2015 Microchip Technology Inc.
DS40001723D-page 287
PIC12(L)F1571/2
FIGURE 27-9:
IDD TYPICAL, EC OSCILLATOR, HIGH-POWER MODE, PIC12LF1571/2 ONLY
2.5
Typical: 25°C
IDD (mA)
2.0
32 MHz
1.5
16 MHz
1.0
8 MHz
0.5
0.0
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
VDD (V)
IDD MAXIMUM, EC OSCILLATOR, HIGH-POWER MODE, PIC12LF1571/2 ONLY
FIGURE 27-10:
2.5
Max: 85°C + 3ı
32 MHz
IDD (mA)
2.0
1.5
16 MHz
1.0
8 MHz
0.5
0.0
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
VDD (V)
DS40001723D-page 288
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
FIGURE 27-11:
IDD TYPICAL, EC OSCILLATOR, HIGH-POWER MODE, PIC12F1571/2 ONLY
2.5
Typical: 25°C
2.0
32 MHz
IDD (mA)
1.5
16 MHz
1.0
8 MHz
0.5
0.0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
VDD (V)
FIGURE 27-12:
IDD MAXIMUM, EC OSCILLATOR, HIGH-POWER MODE, PIC12F1571/2 ONLY
2.5
Max: 85°C + 3ı
32 MHz
IDD (mA)
2.0
1.5
16 MHz
1.0
8 MHz
0.5
0.0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
VDD (V)
 2013-2015 Microchip Technology Inc.
DS40001723D-page 289
PIC12(L)F1571/2
FIGURE 27-13:
IDD, LFINTOSC, FOSC = 31 kHz, PIC12LF1571/2 ONLY
10
Max.
9
Max: 85°C + 3ı
Typical: 25°C
Typical
IDD (µA)
8
7
6
5
4
3
2
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
VDD (V)
FIGURE 27-14:
IDD, LFINTOSC, FOSC = 31 kHz, PIC12F1571/2 ONLY
25
Max: 85°C + 3ı
Typical: 25°C
20
Max.
IDD (µA)
Typical
15
10
5
0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
VDD (V)
DS40001723D-page 290
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
FIGURE 27-15:
IDD, MFINTOSC, FOSC = 500 kHz, PIC12LF1571/2 ONLY
170
160
Max: 85°C + 3ı
Typical: 25°C
Max.
IDD (µA)
150
140
Typical
130
120
110
100
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
VDD (V)
FIGURE 27-16:
IDD, MFINTOSC, FOSC = 500 kHz, PIC12F1571/2 ONLY
260
Max.
Max: 85°C + 3ı
Typical: 25°C
240
Typical
220
IDD (µA)
200
180
160
140
120
100
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
VDD (V)
 2013-2015 Microchip Technology Inc.
DS40001723D-page 291
PIC12(L)F1571/2
FIGURE 27-17:
IDD TYPICAL, HFINTOSC, PIC12LF1571/2 ONLY
1.4
16 MHz
Typical: 25°C
1.2
IDD (mA)
1.0
8 MHz
0.8
4 MHz
0.6
2 MHz
0.4
1 MHz
0.2
0.0
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
VDD (V)
IDD MAXIMUM, HFINTOSC, PIC12LF1571/2 ONLY
FIGURE 27-18:
1.4
16 MHz
Max: 85°C + 3ı
1.2
1.0
IDD (mA)
8 MHz
0.8
4 MHz
2 MHz
0.6
1 MHz
0.4
0.2
0.0
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
VDD (V)
DS40001723D-page 292
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
FIGURE 27-19:
IDD TYPICAL, HFINTOSC, PIC12F1571/2 ONLY
1.4
16 MHz
Typical: 25°C
1.2
1.0
IDD (mA)
8 MHz
0.8
4 MHz
2 MHz
0.6
1 MHz
0.4
0.2
0.0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
VDD (V)
FIGURE 27-20:
IDD MAXIMUM, HFINTOSC, PIC12F1571/2 ONLY
1.6
1.4
16 MHz
Max: 85°C + 3ı
1.2
IDD (mA)
1.0
8 MHz
0.8
4 MHz
2 MHz
0.6
1 MHz
0.4
0.2
0.0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
VDD (V)
 2013-2015 Microchip Technology Inc.
DS40001723D-page 293
PIC12(L)F1571/2
FIGURE 27-21:
IPD BASE, LOW-POWER SLEEP MODE, PIC12LF1571/2 ONLY
350
300
Max: 85°C + 3ı
Typical: 25°C
Max.
IPD (nA
(nA)
250
200
150
100
Typical
50
0
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
VDD (V)
IPD BASE, LOW-POWER SLEEP MODE, PIC12F1571/2 ONLY
FIGURE 27-22:
0.8
0.7
Max: 85°C + 3ı
Typical: 25°C
IPD (µA
(µA)
0.6
Max
0.5
0.4
0.3
Typical
0.2
0.1
0.0
20
2.0
2
2.5
5
3
3.0
0
3
3.5
5
4
4.0
0
4
4.5
5
5
5.0
0
5
5.5
5
6
6.0
0
VDD (V)
DS40001723D-page 294
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
FIGURE 27-23:
IPD, WATCHDOG TIMER (WDT), PIC12LF1571/2 ONLY
1.0
0.9
Max: 85°C + 3ı
Typical: 25°C
0.8
Max.
IPD (µA)
0.7
0.6
Typical
0.5
04
0.4
0.3
0.2
0.1
0.0
16
1.6
1
1.8
8
2
2.0
0
2
2.2
2
2
2.4
4
2
2.6
6
2
2.8
8
3
3.0
0
3
3.2
2
3
3.4
4
3
3.6
6
3
3.8
8
VDD (V)
FIGURE 27-24:
IPD, WATCHDOG TIMER (WDT), PIC12F1571/2 ONLY
1.6
1.4
Max: 85°C + 3ı
Typical: 25°C
1.2
Max.
IPD (µA
(µA)
1.0
0.8
Typical
0.6
0.4
0.2
0.0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
VDD (V)
 2013-2015 Microchip Technology Inc.
DS40001723D-page 295
PIC12(L)F1571/2
FIGURE 27-25:
IPD, FIXED VOLTAGE REFERENCE (FVR), PIC12LF1571/2 ONLY
28
Max: 85°C + 3ı
Typical: 25°C
26
24
Max.
IPD (uA)
22
20
18
T i l
Typical
16
14
12
10
16
1.6
1
1.8
8
2
2.0
0
2
2.2
2
2
2.4
4
2
2.6
6
2
2.8
8
3
3.0
0
3
3.2
2
3
3.4
4
3
3.6
6
3
3.8
8
VDD (V)
FIGURE 27-26:
IPD, FIXED VOLTAGE REFERENCE (FVR), PIC12F1571/2 ONLY
24
22
Max.
20
IPD (uA
(uA)
Typical
18
16
14
Max: 85°C + 3ı
Typical: 25
C
25°C
12
10
20
2.0
2
5
2.5
3
0
3.0
3
5
3.5
4
0
4.0
4
5
4.5
5
0
5.0
5
5
5.5
6
0
6.0
VDD (V)
DS40001723D-page 296
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
FIGURE 27-27:
IPD, BROWN-OUT RESET (BOR), BORV = 1, PIC12LF1571/2 ONLY
9
8.5
Max: 85°C + 3ı
Typical: 25°C
8
Max.
IPD ((uA)
7.5
7
Typical
6.5
6
5.5
5
4.5
24
2.4
2
2.5
5
2
2.6
6
2
2.7
7
2
2.8
8
2
2.9
9
3
3.0
0
3
3.1
1
3
3.2
2
3
3.3
3
3
3.4
4
3
3.5
5
3
3.6
6
3
3.7
7
5
4
5.4
5
6
5.6
VDD (V)
IPD, BROWN-OUT RESET (BOR), BORV = 1, PIC12F1571/2 ONLY
FIGURE 27-28:
12
11
Max: 85°C + 3ı
Typical: 25°C
10
Max.
IPD (uA)
9
8
Typical
7
6
5
4
2
8
2.8
3
0
3.0
3
2
3.2
3
4
3.4
3
6
3.6
3
8
3.8
4
0
4.0
4
2
4.2
4
4
4.4
4
6
4.6
4
8
4.8
5
0
5.0
5
2
5.2
VDD (V)
 2013-2015 Microchip Technology Inc.
DS40001723D-page 297
PIC12(L)F1571/2
FIGURE 27-29:
IPD, LOW-POWER BROWN-OUT RESET (LPBOR = 0), PIC12LF1571/2 ONLY
1.8
16
1.6
Max: 85°C + 3ı
Typical: 25°C
1.4
Max.
IPD (uA
(uA)
1.2
1
0.8
0.6
0.4
Typical
0.2
0
2.4
2.5
2.6
2.7
2.8
2.9
3.0
3.1
3.2
3.3
3.4
3.5
3.6
3.7
VDD (V)
IPD, LOW-POWER BROWN-OUT RESET (LPBOR = 0), PIC12F1571/2 ONLY
FIGURE 27-30:
1.8
Max: 85°C + 3ı
Typical: 25°C
1.6
Max.
1.4
IDD (µA
(µA)
1.2
1.0
0.8
0.6
Typical
0.4
0.2
0.0
28
2.8
3
3.0
0
3
3.2
2
3
3.4
4
3
3.6
6
3
3.8
8
4
4.0
0
4
4.2
2
4
4.4
4
4
4.6
6
4
4.8
8
5
5.0
0
5
5.2
2
5
5.4
4
5
5.6
6
VDD (V)
DS40001723D-page 298
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
FIGURE 27-31:
IPD, ADC NON-CONVERTING, PIC12LF1571/2 ONLY
500
450
Max: 85°C + 3ı
Typical: 25°C
400
Max.
350
IPD (µA)
300
250
200
150
100
Typical
50
0
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
VDD (V)
FIGURE 27-32:
IPD, ADC NON-CONVERTING, PIC12F1571/2 ONLY
1.4
Max: 85°C + 3ı
Typical: 25°C
1.2
Max.
IDD (µA)
1.0
0.8
0.6
0.4
Typical
0.2
0.0
15
1.5
2
0
2.0
2
5
2.5
3
0
3.0
3
5
3.5
4
0
4.0
4
5
4.5
5
0
5.0
5
5
5.5
6
0
6.0
VDD (V)
 2013-2015 Microchip Technology Inc.
DS40001723D-page 299
PIC12(L)F1571/2
FIGURE 27-33:
IPD, COMPARATOR, LOW-POWER MODE (CxSP = 0), PIC12F1571/2 ONLY
22
Max: 85°C + 3ı
Typical: 25°C
20
Max.
18
Typical
IPD (µ
(µA)
16
14
12
10
8
6
4
2
0
2.0
2
5
2.5
3
0
3.0
3
5
3.5
4
0
4.0
4
5
4.5
5
0
5.0
5
5
5.5
6
0
6.0
VDD (V)
IPD, COMPARATOR, NORMAL POWER MODE (CxSP = 1), PIC12LF1571/2 ONLY
FIGURE 27-34:
32
Max: -40°C + 3ı
Typical: 25°C
30
28
Max.
IPD (µA
(µA)
26
24
22
Typical
20
18
16
14
12
16
1.6
1
1.8
8
2
2.0
0
2
2.2
2
2
2.4
4
2
2.6
6
2
2.8
8
3
3.0
0
3
3.2
2
3
3.4
4
3
3.6
6
3
3.8
8
VDD (V)
DS40001723D-page 300
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
FIGURE 27-35:
IPD, COMPARATOR, NORMAL POWER MODE (CxSP = 1), PIC12F1571/2 ONLY
45
Max: -40°C
40°C + 3ı
Typical: 25°C
40
Max.
35
IPD (µA
(µA)
Typical
30
25
20
15
10
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
VDD (V)
 2013-2015 Microchip Technology Inc.
DS40001723D-page 301
PIC12(L)F1571/2
FIGURE 27-36:
IPD, PWM, HFINTOSC MODE (16 MHz), PIC12LF1571/2 ONLY
1100
Max: 85°C + 3ı
Typical: 25°C
1000
900
Max.
IPD (µA
(µA)
800
700
Typical
600
500
400
300
200
16
1.6
1
8
1.8
2
0
2.0
2
2
2.2
2
4
2.4
2
6
2.6
2
8
2.8
3
0
3.0
3
2
3.2
3
4
3.4
3
6
3.6
3
8
3.8
VDD (V)
FIGURE 27-37:
IPD, PWM, HFINTOSC MODE (16 MHz), PIC12F1571/2 ONLY
1,200
Max: 85°C + 3ı
Typical: 25°C
1,100
Max.
1,000
Typical
IPD (µA
(µA)
900
800
700
600
500
400
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
VDD (V)
DS40001723D-page 302
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
FIGURE 27-38:
FVR STABILIZATION PERIOD
60
Max: Typical + 3ı
Typical: statistical mean @ 25°C
50
Max.
Time (us)
40
Typical
30
20
Note:
The FVR Stabilization Period applies when:
1) coming out of RESET or exiting Sleep mode for PIC12/16LFxxxx devices.
2) when exiting sleep mode with VREGPM = 1 for PIC12/16Fxxxx devices
In all other cases, the FVR is stable when released from RESET.
10
0
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
VDD (V)
 2013-2015 Microchip Technology Inc.
DS40001723D-page 303
PIC12(L)F1571/2
NOTES:
DS40001723D-page 304
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
28.0
DEVELOPMENT SUPPORT
The PIC® microcontrollers (MCU) and dsPIC® digital
signal controllers (DSC) are supported with a full range
of software and hardware development tools:
• Integrated Development Environment
- MPLAB® X IDE Software
• Compilers/Assemblers/Linkers
- MPLAB XC Compiler
- MPASMTM Assembler
- MPLINKTM Object Linker/
MPLIBTM Object Librarian
- MPLAB Assembler/Linker/Librarian for
Various Device Families
• Simulators
- MPLAB X SIM Software Simulator
• Emulators
- MPLAB REAL ICE™ In-Circuit Emulator
• In-Circuit Debuggers/Programmers
- MPLAB ICD 3
- PICkit™ 3
• Device Programmers
- MPLAB PM3 Device Programmer
• Low-Cost Demonstration/Development Boards,
Evaluation Kits and Starter Kits
• Third-party development tools
28.1
MPLAB X Integrated Development
Environment Software
The MPLAB X IDE is a single, unified graphical user
interface for Microchip and third-party software, and
hardware development tool that runs on Windows®,
Linux and Mac OS® X. Based on the NetBeans IDE,
MPLAB X IDE is an entirely new IDE with a host of free
software components and plug-ins for highperformance application development and debugging.
Moving between tools and upgrading from software
simulators to hardware debugging and programming
tools is simple with the seamless user interface.
With complete project management, visual call graphs,
a configurable watch window and a feature-rich editor
that includes code completion and context menus,
MPLAB X IDE is flexible and friendly enough for new
users. With the ability to support multiple tools on
multiple projects with simultaneous debugging, MPLAB
X IDE is also suitable for the needs of experienced
users.
Feature-Rich Editor:
• Color syntax highlighting
• Smart code completion makes suggestions and
provides hints as you type
• Automatic code formatting based on user-defined
rules
• Live parsing
User-Friendly, Customizable Interface:
• Fully customizable interface: toolbars, toolbar
buttons, windows, window placement, etc.
• Call graph window
Project-Based Workspaces:
•
•
•
•
Multiple projects
Multiple tools
Multiple configurations
Simultaneous debugging sessions
File History and Bug Tracking:
• Local file history feature
• Built-in support for Bugzilla issue tracker
 2013-2015 Microchip Technology Inc.
DS40001723D-page 305
PIC12(L)F1571/2
28.2
MPLAB XC Compilers
The MPLAB XC Compilers are complete ANSI C
compilers for all of Microchip’s 8, 16, and 32-bit MCU
and DSC devices. These compilers provide powerful
integration capabilities, superior code optimization and
ease of use. MPLAB XC Compilers run on Windows,
Linux or MAC OS X.
For easy source level debugging, the compilers provide
debug information that is optimized to the MPLAB X
IDE.
The free MPLAB XC Compiler editions support all
devices and commands, with no time or memory
restrictions, and offer sufficient code optimization for
most applications.
MPLAB XC Compilers include an assembler, linker and
utilities. The assembler generates relocatable object
files that can then be archived or linked with other relocatable object files and archives to create an executable file. MPLAB XC Compiler uses the assembler to
produce its object file. Notable features of the assembler include:
•
•
•
•
•
•
Support for the entire device instruction set
Support for fixed-point and floating-point data
Command-line interface
Rich directive set
Flexible macro language
MPLAB X IDE compatibility
28.3
MPASM Assembler
The MPASM Assembler is a full-featured, universal
macro assembler for PIC10/12/16/18 MCUs.
The MPASM Assembler generates relocatable object
files for the MPLINK Object Linker, Intel® standard HEX
files, MAP files to detail memory usage and symbol
reference, absolute LST files that contain source lines
and generated machine code, and COFF files for
debugging.
The MPASM Assembler features include:
28.4
MPLINK Object Linker/
MPLIB Object Librarian
The MPLINK Object Linker combines relocatable
objects created by the MPASM Assembler. It can link
relocatable objects from precompiled libraries, using
directives from a linker script.
The MPLIB Object Librarian manages the creation and
modification of library files of precompiled code. When
a routine from a library is called from a source file, only
the modules that contain that routine will be linked in
with the application. This allows large libraries to be
used efficiently in many different applications.
The object linker/library features include:
• Efficient linking of single libraries instead of many
smaller files
• Enhanced code maintainability by grouping
related modules together
• Flexible creation of libraries with easy module
listing, replacement, deletion and extraction
28.5
MPLAB Assembler, Linker and
Librarian for Various Device
Families
MPLAB Assembler produces relocatable machine
code from symbolic assembly language for PIC24,
PIC32 and dsPIC DSC devices. MPLAB XC Compiler
uses the assembler to produce its object file. The
assembler generates relocatable object files that can
then be archived or linked with other relocatable object
files and archives to create an executable file. Notable
features of the assembler include:
•
•
•
•
•
•
Support for the entire device instruction set
Support for fixed-point and floating-point data
Command-line interface
Rich directive set
Flexible macro language
MPLAB X IDE compatibility
• Integration into MPLAB X IDE projects
• User-defined macros to streamline
assembly code
• Conditional assembly for multipurpose
source files
• Directives that allow complete control over the
assembly process
DS40001723D-page 306
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
28.6
MPLAB X SIM Software Simulator
The MPLAB X SIM Software Simulator allows code
development in a PC-hosted environment by simulating the PIC MCUs and dsPIC DSCs on an instruction
level. On any given instruction, the data areas can be
examined or modified and stimuli can be applied from
a comprehensive stimulus controller. Registers can be
logged to files for further run-time analysis. The trace
buffer and logic analyzer display extend the power of
the simulator to record and track program execution,
actions on I/O, most peripherals and internal registers.
The MPLAB X SIM Software Simulator fully supports
symbolic debugging using the MPLAB XC Compilers,
and the MPASM and MPLAB Assemblers. The software simulator offers the flexibility to develop and
debug code outside of the hardware laboratory environment, making it an excellent, economical software
development tool.
28.7
MPLAB REAL ICE In-Circuit
Emulator System
The MPLAB REAL ICE In-Circuit Emulator System is
Microchip’s next generation high-speed emulator for
Microchip Flash DSC and MCU devices. It debugs and
programs all 8, 16 and 32-bit MCU, and DSC devices
with the easy-to-use, powerful graphical user interface of
the MPLAB X IDE.
The emulator is connected to the design engineer’s
PC using a high-speed USB 2.0 interface and is
connected to the target with either a connector
compatible with in-circuit debugger systems (RJ-11)
or with the new high-speed, noise tolerant, LowVoltage Differential Signal (LVDS) interconnection
(CAT5).
The emulator is field upgradable through future firmware
downloads in MPLAB X IDE. MPLAB REAL ICE offers
significant advantages over competitive emulators
including full-speed emulation, run-time variable
watches, trace analysis, complex breakpoints, logic
probes, a ruggedized probe interface and long (up to
three meters) interconnection cables.
 2013-2015 Microchip Technology Inc.
28.8
MPLAB ICD 3 In-Circuit Debugger
System
The MPLAB ICD 3 In-Circuit Debugger System is
Microchip’s most cost-effective, high-speed hardware
debugger/programmer for Microchip Flash DSC and
MCU devices. It debugs and programs PIC Flash
microcontrollers and dsPIC DSCs with the powerful,
yet easy-to-use graphical user interface of the MPLAB
IDE.
The MPLAB ICD 3 In-Circuit Debugger probe is
connected to the design engineer’s PC using a highspeed USB 2.0 interface and is connected to the target
with a connector compatible with the MPLAB ICD 2 or
MPLAB REAL ICE systems (RJ-11). MPLAB ICD 3
supports all MPLAB ICD 2 headers.
28.9
PICkit 3 In-Circuit Debugger/
Programmer
The MPLAB PICkit 3 allows debugging and programming of PIC and dsPIC Flash microcontrollers at a most
affordable price point using the powerful graphical user
interface of the MPLAB IDE. The MPLAB PICkit 3 is
connected to the design engineer’s PC using a fullspeed USB interface and can be connected to the target via a Microchip debug (RJ-11) connector (compatible with MPLAB ICD 3 and MPLAB REAL ICE). The
connector uses two device I/O pins and the Reset line
to implement in-circuit debugging and In-Circuit Serial
Programming™ (ICSP™).
28.10 MPLAB PM3 Device Programmer
The MPLAB PM3 Device Programmer is a universal,
CE compliant device programmer with programmable
voltage verification at VDDMIN and VDDMAX for
maximum reliability. It features a large LCD display
(128 x 64) for menus and error messages, and a modular, detachable socket assembly to support various
package types. The ICSP cable assembly is included
as a standard item. In Stand-Alone mode, the MPLAB
PM3 Device Programmer can read, verify and program
PIC devices without a PC connection. It can also set
code protection in this mode. The MPLAB PM3
connects to the host PC via an RS-232 or USB cable.
The MPLAB PM3 has high-speed communications and
optimized algorithms for quick programming of large
memory devices, and incorporates an MMC card for file
storage and data applications.
DS40001723D-page 307
PIC12(L)F1571/2
28.11 Demonstration/Development
Boards, Evaluation Kits, and
Starter Kits
A wide variety of demonstration, development and
evaluation boards for various PIC MCUs and dsPIC
DSCs allows quick application development on fully
functional systems. Most boards include prototyping
areas for adding custom circuitry and provide application firmware and source code for examination and
modification.
The boards support a variety of features, including LEDs,
temperature sensors, switches, speakers, RS-232
interfaces, LCD displays, potentiometers and additional
EEPROM memory.
28.12 Third-Party Development Tools
Microchip also offers a great collection of tools from
third-party vendors. These tools are carefully selected
to offer good value and unique functionality.
• Device Programmers and Gang Programmers
from companies, such as SoftLog and CCS
• Software Tools from companies, such as Gimpel
and Trace Systems
• Protocol Analyzers from companies, such as
Saleae and Total Phase
• Demonstration Boards from companies, such as
MikroElektronika, Digilent® and Olimex
• Embedded Ethernet Solutions from companies,
such as EZ Web Lynx, WIZnet and IPLogika®
The demonstration and development boards can be
used in teaching environments, for prototyping custom
circuits and for learning about various microcontroller
applications.
In addition to the PICDEM™ and dsPICDEM™
demonstration/development board series of circuits,
Microchip has a line of evaluation kits and demonstration software for analog filter design, KEELOQ® security
ICs, CAN, IrDA®, PowerSmart battery management,
SEEVAL® evaluation system, Sigma-Delta ADC, flow
rate sensing, plus many more.
Also available are starter kits that contain everything
needed to experience the specified device. This usually
includes a single application and debug capability, all
on one board.
Check the Microchip web page (www.microchip.com)
for the complete list of demonstration, development
and evaluation kits.
DS40001723D-page 308
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
29.0
PACKAGING INFORMATION
29.1
Package Marking Information
8-Lead PDIP (300 mil)
XXXXXXXX
XXXXXNNN
YYWW
8-Lead SOIC (3.90 mm)
NNN
Legend: XX...X
Y
YY
WW
NNN
e3
*
Note:
Example
12F1571
E/Pe3 017
1310
Example
12F1571
E/SN1310
017
Customer-specific information
Year code (last digit of calendar year)
Year code (last 2 digits of calendar year)
Week code (week of January 1 is week ‘01’)
Alphanumeric traceability code
Pb-free JEDEC® designator for Matte Tin (Sn)
This package is Pb-free. The Pb-free JEDEC designator ( e3 )
can be found on the outer packaging for this package.
In the event the full Microchip part number cannot be marked on one line, it will
be carried over to the next line, thus limiting the number of available
characters for customer-specific information.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 309
PIC12(L)F1571/2
Package Marking Information (Continued)
8-Lead MSOP (3x3 mm)
Example
L1571I
310017
8-Lead DFN (3x3x0.9 mm)
8-Lead UDFN (3x3x0.5 mm)
XXXX
YYWW
NNN
PIN 1
DS40001723D-page 310
Example
MFQ0
1312
017
PIN 1
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
TABLE 29-1:
8-LEAD 3x3x0.9 DFN (MF) TOP
MARKING
Part Number
Marking
TABLE 29-2:
8-LEAD 3x3x0.5 UDFN (RF)
TOP MARKING
Part Number
Marking
PIC12F1571-E/MF
MFY0/YYWW/NNN
PIC12F1571-E/MF
MFY0/YYWW/NNN
PIC12F1572-E/MF
MGA0/YYWW/NNN
PIC12F1572-E/MF
MGA0/YYWW/NNN
PIC12F1571-I/MF
MFZ0
PIC12F1571-I/MF
MFZ0
PIC12F1572-I/MF
MGB0
PIC12F1572-I/MF
MGB0
PIC12LF1571-E/MF
MGC0
PIC12LF1571-E/MF
MGC0
PIC12LF1572-E/MF
MGE0
PIC12LF1572-E/MF
MGE0
PIC12LF1571-I/MF
MGD0
PIC12LF1571-I/MF
MGD0
PIC12LF1572-I/MF
MGF0
PIC12LF1572-I/MF
MGF0
 2013-2015 Microchip Technology Inc.
DS40001723D-page 311
PIC12(L)F1571/2
29.2
Package Details
The following sections give the technical details of the packages.
8-Lead Plastic Dual In-Line (P) - 300 mil Body [PDIP]
Note:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
D
A
N
B
E1
NOTE 1
1
2
TOP VIEW
E
C
A2
A
PLANE
L
c
A1
e
eB
8X b1
8X b
.010
C
SIDE VIEW
END VIEW
Microchip Technology Drawing No. C04-018D Sheet 1 of 2
DS40001723D-page 312
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
8-Lead Plastic Dual In-Line (P) - 300 mil Body [PDIP]
Note:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
ALTERNATE LEAD DESIGN
(VENDOR DEPENDENT)
DATUM A
DATUM A
b
b
e
2
e
2
e
Units
Dimension Limits
Number of Pins
N
e
Pitch
Top to Seating Plane
A
Molded Package Thickness
A2
Base to Seating Plane
A1
Shoulder to Shoulder Width
E
Molded Package Width
E1
Overall Length
D
Tip to Seating Plane
L
c
Lead Thickness
Upper Lead Width
b1
b
Lower Lead Width
Overall Row Spacing
eB
§
e
MIN
.115
.015
.290
.240
.348
.115
.008
.040
.014
-
INCHES
NOM
8
.100 BSC
.130
.310
.250
.365
.130
.010
.060
.018
-
MAX
.210
.195
.325
.280
.400
.150
.015
.070
.022
.430
Notes:
1. Pin 1 visual index feature may vary, but must be located within the hatched area.
2. § Significant Characteristic
3. Dimensions D and E1 do not include mold flash or protrusions. Mold flash or
protrusions shall not exceed .010" per side.
4. Dimensioning and tolerancing per ASME Y14.5M
BSC: Basic Dimension. Theoretically exact value shown without tolerances.
Microchip Technology Drawing No. C04-018D Sheet 2 of 2
 2013-2015 Microchip Technology Inc.
DS40001723D-page 313
PIC12(L)F1571/2
Note:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
DS40001723D-page 314
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
Note:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
 2013-2015 Microchip Technology Inc.
DS40001723D-page 315
PIC12(L)F1571/2
!"#$%
&
!
"#$%&"'""
($)
%
*++&&&!
!+$
DS40001723D-page 316
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
Note:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
 2013-2015 Microchip Technology Inc.
DS40001723D-page 317
PIC12(L)F1571/2
Note:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
DS40001723D-page 318
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
Note:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
 2013-2015 Microchip Technology Inc.
DS40001723D-page 319
PIC12(L)F1571/2
Note:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
DS40001723D-page 320
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
Note:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
 2013-2015 Microchip Technology Inc.
DS40001723D-page 321
PIC12(L)F1571/2
Note:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
DS40001723D-page 322
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
8-Lead Ultra Thin Plastic Dual Flat, No Lead Package (RF) - 3x3x0.50 mm Body [UDFN]
Note:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
D
A
B
N
(DATUM A)
(DATUM B)
E
NOTE 1
2X
0.10 C
1
2X
2
TOP VIEW
0.10 C
0.05 C
C
SEATING
PLANE
A1
A
8X
(A3)
0.05 C
SIDE VIEW
0.10
C A B
D2
1
2
L
0.10
C A B
E2
NOTE 1
K
N
e
8X b
0.10
e
2
C A B
BOTTOM VIEW
Microchip Technology Drawing C04-254A Sheet 1 of 2
 2013-2015 Microchip Technology Inc.
DS40001723D-page 323
PIC12(L)F1571/2
8-Lead Ultra Thin Plastic Dual Flat, No Lead Package (RF) - 3x3x0.50 mm Body [UDFN]
Note:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
Units
Dimension Limits
Number of Terminals
N
e
Pitch
Overall Height
A
Standoff
A1
A3
Terminal Thickness
Overall Width
E
E2
Exposed Pad Width
Overall Length
D
D2
Exposed Pad Length
Terminal Width
b
Terminal Length
L
K
Terminal-to-Exposed-Pad
MIN
0.45
0.00
1.40
2.20
0.25
0.35
0.20
MILLIMETERS
NOM
8
0.65 BSC
0.50
0.02
0.065 REF
3.00 BSC
1.50
3.00 BSC
2.30
0.30
0.45
-
MAX
0.55
0.05
1.60
2.40
0.35
0.55
-
Notes:
1. Pin 1 visual index feature may vary, but must be located within the hatched area.
2. Package is saw singulated
3. Dimensioning and tolerancing per ASME Y14.5M
BSC: Basic Dimension. Theoretically exact value shown without tolerances.
REF: Reference Dimension, usually without tolerance, for information purposes only.
Microchip Technology Drawing C04-254A Sheet 2 of 2
DS40001723D-page 324
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
8-Lead Ultra Thin Plastic Dual Flat, No Lead Package (RF) - 3x3x0.50 mm Body [UDFN]
Note:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
C
X2
E
Y2
X1
G1
G2
SILK SCREEN
Y1
RECOMMENDED LAND PATTERN
Units
Dimension Limits
E
Contact Pitch
Optional Center Pad Width
X2
Optional Center Pad Length
Y2
Contact Pad Spacing
C
Contact Pad Width (X8)
X1
Contact Pad Length (X8)
Y1
Contact Pad to Contact Pad (X6)
G1
Contact Pad to Center Pad (X8)
G2
MIN
MILLIMETERS
NOM
0.65 BSC
MAX
1.60
2.40
2.90
0.35
0.85
0.20
0.30
Notes:
1. Dimensioning and tolerancing per ASME Y14.5M
BSC: Basic Dimension. Theoretically exact value shown without tolerances.
Microchip Technology Drawing C04-2254A
 2013-2015 Microchip Technology Inc.
DS40001723D-page 325
PIC12(L)F1571/2
NOTES:
DS40001723D-page 326
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
APPENDIX A:
DATA SHEET
REVISION HISTORY
Revision A (10/2013)
Original release of this document.
Revision B (2/2014)
Updated PIC12(L)F1571/2 Family Types table
Program Memory Flash heading (words to K words).
Revision C (8/2014)
Updated PWM chapter. Changed to Final data sheet.
Updated IDD and IPD parameters in the Electrical
Specification chapter. Added Characterization Graphs.
Added Section
Conventions.
1.1:
Register
and
Bit
Naming
Updated Figures 5-3 and 15-5. Updated Tables 3-1,
3-7, and 3-10. Updated Section 15.2.5. Updated Equation 15-1.
Revision D (8/2015)
Updated Clocking Structure, Memory, Low-Power
Features, Family Types table and Pin Diagram Table
on cover pages.
Added Sections 3.2: High-Endurance Flash and
5.4: Clock Switching Before Sleep. Added Table 29-2
and 8-pin UDFN packaging.
Updated Examples 3-2 and 15-1.
Updated Figures 8-1, 21-1, 22-8 through 22-13 and
23-1.
Updated Registers 7-5, 8-1, 22-6 and 23-3.
Updated Sections 8.2.2, 15.2.6, 16.0, 21.0, 21.4.2,
22.3.3, 23.9.1.2, 23.11.1, 26.1 and 29.1.
Updated Tables 1, 3-3, 3-4, 3-10, 5-1, 16-1, 17-3, 22-2,
23-2, 26-6, 26-8 and 29-1.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 327
PIC12(L)F1571/2
NOTES:
DS40001723D-page 328
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
THE MICROCHIP WEB SITE
CUSTOMER SUPPORT
Microchip provides online support via our WWW site at
www.microchip.com. This web site is used as a means
to make files and information easily available to
customers. Accessible by using your favorite Internet
browser, the web site contains the following
information:
Users of Microchip products can receive assistance
through several channels:
• Product Support – Data sheets and errata,
application notes and sample programs, design
resources, user’s guides and hardware support
documents, latest software releases and archived
software
• General Technical Support – Frequently Asked
Questions (FAQ), technical support requests,
online discussion groups, Microchip consultant
program member listing
• Business of Microchip – Product selector and
ordering guides, latest Microchip press releases,
listing of seminars and events, listings of
Microchip sales offices, distributors and factory
representatives
•
•
•
•
Distributor or Representative
Local Sales Office
Field Application Engineer (FAE)
Technical Support
Customers
should
contact
their
distributor,
representative or Field Application Engineer (FAE) for
support. Local sales offices are also available to help
customers. A listing of sales offices and locations is
included in the back of this document.
Technical support is available through the web site
at: http://microchip.com/support
CUSTOMER CHANGE NOTIFICATION
SERVICE
Microchip’s customer notification service helps keep
customers current on Microchip products. Subscribers
will receive e-mail notification whenever there are
changes, updates, revisions or errata related to a
specified product family or development tool of interest.
To register, access the Microchip web site at
www.microchip.com. Under “Support”, click on
“Customer Change Notification” and follow the
registration instructions.
 2013-2015 Microchip Technology Inc.
DS40001723D-page 329
PIC12(L)F1571/2
NOTES:
DS40001723D-page 330
 2013-2015 Microchip Technology Inc.
PIC12(L)F1571/2
PRODUCT IDENTIFICATION SYSTEM
To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office.
[X](1)
PART NO.
Device
-
X
Tape and Reel Temperature
Option
Range
/XX
XXX
Package
Pattern
Examples:
a)
b)
Device:
PIC12LF1571, PIC12F1571
PIC12LF1572, PIC12F1572
Tape and Reel
Option:
Blank
T
= Standard packaging (tube or tray)
= Tape and Reel(1)
Temperature
Range:
I
E
= -40C to +85C
= -40C to +125C
Package:(2)
MF
MS
P
SN
RF
Pattern:
QTP, SQTP, Code or Special Requirements
(blank otherwise)
c)
=
=
=
=
=
(Industrial)
(Extended)
Micro Lead Frame (DFN) 3x3x0.9 mm
MSOP
Plastic DIP
SOIC
Micro Lead Frame (UDFN) 3x3x0.5 mm
 2013-2015 Microchip Technology Inc.
PIC12LF1571T - I/SO
Tape and Reel,
Industrial temperature,
SOIC package
PIC12F1572 - I/P
Industrial temperature,
PDIP package
PIC12F1571-E/MF
Extended Temperature,
DFN package
Note 1: Tape and Reel identifier only appears in the
catalog part number description. This identifier
is used for ordering purposes and is not printed
on the device package. Check with your
Microchip Sales Office for package availability
with the Tape and Reel option.
2: For other small form-factor package availability
and marking information, please visit
www.microchip.com/packaging or contact your
local sales office.
DS40001723D-page 331
PIC12(L)F1571/2
NOTES:
DS40001723D-page 332
 2013-2015 Microchip Technology Inc.
Note the following details of the code protection feature on Microchip devices:
•
Microchip products meet the specification contained in their particular Microchip Data Sheet.
•
Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.
•
There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.
•
Microchip is willing to work with the customer who is concerned about the integrity of their code.
•
Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as “unbreakable.”
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts
allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.
Information contained in this publication regarding device
applications and the like is provided only for your convenience
and may be superseded by updates. It is your responsibility to
ensure that your application meets with your specifications.
MICROCHIP MAKES NO REPRESENTATIONS OR
WARRANTIES OF ANY KIND WHETHER EXPRESS OR
IMPLIED, WRITTEN OR ORAL, STATUTORY OR
OTHERWISE, RELATED TO THE INFORMATION,
INCLUDING BUT NOT LIMITED TO ITS CONDITION,
QUALITY, PERFORMANCE, MERCHANTABILITY OR
FITNESS FOR PURPOSE. Microchip disclaims all liability
arising from this information and its use. Use of Microchip
devices in life support and/or safety applications is entirely at
the buyer’s risk, and the buyer agrees to defend, indemnify and
hold harmless Microchip from any and all damages, claims,
suits, or expenses resulting from such use. No licenses are
conveyed, implicitly or otherwise, under any Microchip
intellectual property rights unless otherwise stated.
Trademarks
The Microchip name and logo, the Microchip logo, dsPIC,
FlashFlex, flexPWR, JukeBlox, KEELOQ, KEELOQ logo, Kleer,
LANCheck, MediaLB, MOST, MOST logo, MPLAB,
OptoLyzer, PIC, PICSTART, PIC32 logo, RightTouch, SpyNIC,
SST, SST Logo, SuperFlash and UNI/O are registered
trademarks of Microchip Technology Incorporated in the
U.S.A. and other countries.
The Embedded Control Solutions Company and mTouch are
registered trademarks of Microchip Technology Incorporated
in the U.S.A.
Analog-for-the-Digital Age, BodyCom, chipKIT, chipKIT logo,
CodeGuard, dsPICDEM, dsPICDEM.net, ECAN, In-Circuit
Serial Programming, ICSP, Inter-Chip Connectivity, KleerNet,
KleerNet logo, MiWi, MPASM, MPF, MPLAB Certified logo,
MPLIB, MPLINK, MultiTRAK, NetDetach, Omniscient Code
Generation, PICDEM, PICDEM.net, PICkit, PICtail,
RightTouch logo, REAL ICE, SQI, Serial Quad I/O, Total
Endurance, TSHARC, USBCheck, VariSense, ViewSpan,
WiperLock, Wireless DNA, and ZENA are trademarks of
Microchip Technology Incorporated in the U.S.A. and other
countries.
SQTP is a service mark of Microchip Technology Incorporated
in the U.S.A.
Silicon Storage Technology is a registered trademark of
Microchip Technology Inc. in other countries.
GestIC is a registered trademark of Microchip Technology
Germany II GmbH & Co. KG, a subsidiary of Microchip
Technology Inc., in other countries.
All other trademarks mentioned herein are property of their
respective companies.
© 2013-2015, Microchip Technology Incorporated, Printed in
the U.S.A., All Rights Reserved.
ISBN: 978-1-63277-715-7
QUALITY MANAGEMENT SYSTEM
CERTIFIED BY DNV
== ISO/TS 16949 ==
 2013-2015 Microchip Technology Inc.
Microchip received ISO/TS-16949:2009 certification for its worldwide
headquarters, design and wafer fabrication facilities in Chandler and
Tempe, Arizona; Gresham, Oregon and design centers in California
and India. The Company’s quality system processes and procedures
are for its PIC® MCUs and dsPIC® DSCs, KEELOQ® code hopping
devices, Serial EEPROMs, microperipherals, nonvolatile memory and
analog products. In addition, Microchip’s quality system for the design
and manufacture of development systems is ISO 9001:2000 certified.
DS40001723D-page 333
Worldwide Sales and Service
AMERICAS
ASIA/PACIFIC
ASIA/PACIFIC
EUROPE
Corporate Office
2355 West Chandler Blvd.
Chandler, AZ 85224-6199
Tel: 480-792-7200
Fax: 480-792-7277
Technical Support:
http://www.microchip.com/
support
Web Address:
www.microchip.com
Asia Pacific Office
Suites 3707-14, 37th Floor
Tower 6, The Gateway
Harbour City, Kowloon
China - Xiamen
Tel: 86-592-2388138
Fax: 86-592-2388130
Austria - Wels
Tel: 43-7242-2244-39
Fax: 43-7242-2244-393
China - Zhuhai
Tel: 86-756-3210040
Fax: 86-756-3210049
Denmark - Copenhagen
Tel: 45-4450-2828
Fax: 45-4485-2829
India - Bangalore
Tel: 91-80-3090-4444
Fax: 91-80-3090-4123
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Tel: 33-1-69-53-63-20
Fax: 33-1-69-30-90-79
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Duluth, GA
Tel: 678-957-9614
Fax: 678-957-1455
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Tel: 86-10-8569-7000
Fax: 86-10-8528-2104
India - New Delhi
Tel: 91-11-4160-8631
Fax: 91-11-4160-8632
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Tel: 49-2129-3766400
Hong Kong
Tel: 852-2943-5100
Fax: 852-2401-3431
Australia - Sydney
Tel: 61-2-9868-6733
Fax: 61-2-9868-6755
Austin, TX
Tel: 512-257-3370
China - Chengdu
Tel: 86-28-8665-5511
Fax: 86-28-8665-7889
Boston
Westborough, MA
Tel: 774-760-0087
Fax: 774-760-0088
China - Chongqing
Tel: 86-23-8980-9588
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Itasca, IL
Tel: 630-285-0071
Fax: 630-285-0075
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Tel: 216-447-0464
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Tel: 972-818-7423
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Tel: 248-848-4000
Houston, TX
Tel: 281-894-5983
Indianapolis
Noblesville, IN
Tel: 317-773-8323
Fax: 317-773-5453
Los Angeles
Mission Viejo, CA
Tel: 949-462-9523
Fax: 949-462-9608
New York, NY
Tel: 631-435-6000
San Jose, CA
Tel: 408-735-9110
Canada - Toronto
Tel: 905-673-0699
Fax: 905-673-6509
China - Dongguan
Tel: 86-769-8702-9880
China - Hangzhou
Tel: 86-571-8792-8115
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Germany - Karlsruhe
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Tel: 91-20-3019-1500
Germany - Munich
Tel: 49-89-627-144-0
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Tel: 81-6-6152-7160
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Italy - Milan
Tel: 39-0331-742611
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Japan - Tokyo
Tel: 81-3-6880- 3770
Fax: 81-3-6880-3771
Italy - Venice
Tel: 39-049-7625286
Korea - Daegu
Tel: 82-53-744-4301
Fax: 82-53-744-4302
Netherlands - Drunen
Tel: 31-416-690399
Fax: 31-416-690340
China - Hong Kong SAR
Tel: 852-2943-5100
Fax: 852-2401-3431
Korea - Seoul
Tel: 82-2-554-7200
Fax: 82-2-558-5932 or
82-2-558-5934
China - Nanjing
Tel: 86-25-8473-2460
Fax: 86-25-8473-2470
Malaysia - Kuala Lumpur
Tel: 60-3-6201-9857
Fax: 60-3-6201-9859
China - Qingdao
Tel: 86-532-8502-7355
Fax: 86-532-8502-7205
Malaysia - Penang
Tel: 60-4-227-8870
Fax: 60-4-227-4068
China - Shanghai
Tel: 86-21-5407-5533
Fax: 86-21-5407-5066
Philippines - Manila
Tel: 63-2-634-9065
Fax: 63-2-634-9069
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Tel: 65-6334-8870
Fax: 65-6334-8850
China - Shenzhen
Tel: 86-755-8864-2200
Fax: 86-755-8203-1760
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Tel: 886-3-5778-366
Fax: 886-3-5770-955
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Tel: 86-27-5980-5300
Fax: 86-27-5980-5118
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Tel: 886-7-213-7828
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Tel: 86-29-8833-7252
Fax: 86-29-8833-7256
Poland - Warsaw
Tel: 48-22-3325737
Spain - Madrid
Tel: 34-91-708-08-90
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Sweden - Stockholm
Tel: 46-8-5090-4654
UK - Wokingham
Tel: 44-118-921-5800
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Taiwan - Taipei
Tel: 886-2-2508-8600
Fax: 886-2-2508-0102
Thailand - Bangkok
Tel: 66-2-694-1351
Fax: 66-2-694-1350
07/14/15
DS40001723D-page 334
 2013-2015 Microchip Technology Inc.