HT66F302_303v100.pdf

Cost-Effective 8-Bit Flash MCU with EEPROM
HT66F302/HT66F303
Revision: V1.00
Date: ������������
May 06, 2016
HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
Table of Contents
Features................................................................................................................. 6
CPU Features...............................................................................................................................6
Peripheral Features.......................................................................................................................6
General Description.............................................................................................. 7
Selection Table...................................................................................................... 7
Block Diagram....................................................................................................... 7
Pin Assignment..................................................................................................... 8
Pin Description..................................................................................................... 9
Absolute Maximum Ratings............................................................................... 12
D.C. Characteristics............................................................................................ 13
A.C. Characteristics............................................................................................ 14
ADC Electrical Characteristics.......................................................................... 15
Power on Reset Electrical Characteristics....................................................... 16
System Architecture........................................................................................... 16
Clocking and Pipelining...............................................................................................................16
Program Counter.........................................................................................................................17
Stack...........................................................................................................................................18
Arithmetic and Logic Unit – ALU.................................................................................................18
Flash Program Memory...................................................................................... 19
Structure......................................................................................................................................19
Special Vectors...........................................................................................................................19
Look-up Table..............................................................................................................................19
Table Program Example..............................................................................................................20
In Circuit Programming...............................................................................................................21
On-Chip Debug Support – OCDS...............................................................................................21
RAM Data Memory.............................................................................................. 22
Structure......................................................................................................................................22
General Purpose Data Memory..................................................................................................22
Special Purpose Data Memory...................................................................................................22
Special Function Register Description............................................................. 25
Indirect Addressing Registers – IAR0, IAR1...............................................................................25
Memory Pointers – MP0, MP1....................................................................................................25
Bank Pointer – BP.......................................................................................................................26
Accumulator – ACC.....................................................................................................................26
Program Counter Low Register – PCL........................................................................................26
Look-up Table Registers – TBLP, TBLH......................................................................................27
Status Register – STATUS..........................................................................................................27
Rev. 1.00
2
May 06, 2016
HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
EEPROM Data Memory....................................................................................... 28
EEPROM Data Memory Structure..............................................................................................28
EEPROM Registers....................................................................................................................29
Reading Data from the EEPROM ..............................................................................................31
Writing Data to the EEPROM......................................................................................................31
Write Protection...........................................................................................................................31
EEPROM Interrupt......................................................................................................................31
Programming Considerations......................................................................................................32
Oscillators........................................................................................................... 33
Oscillator Overview.....................................................................................................................33
System Clock Configurations......................................................................................................33
Internal RC Oscillator – HIRC.....................................................................................................34
Internal 32kHz Oscillator – LIRC.................................................................................................34
Supplementary Oscillator............................................................................................................34
Operating Modes and System Clocks.............................................................. 34
System Clocks............................................................................................................................34
System Operation Modes............................................................................................................35
Control Register..........................................................................................................................37
Operating Mode Switching .........................................................................................................39
Standby Current Considerations.................................................................................................43
Wake-up......................................................................................................................................43
Watchdog Timer.................................................................................................. 44
Watchdog Timer Clock Source....................................................................................................44
Watchdog Timer Control Register...............................................................................................44
Watchdog Timer Operation.........................................................................................................45
Reset and Initialisation....................................................................................... 46
Reset Functions..........................................................................................................................46
Reset Initial Conditions...............................................................................................................50
Input/Output Ports.............................................................................................. 52
Pull-high Resistors......................................................................................................................53
Port A Wake-up...........................................................................................................................54
I/O Port Control Registers...........................................................................................................54
Pin-shared Functions..................................................................................................................55
Pin-shared Registers...................................................................................................................55
I/O Pin Structures........................................................................................................................57
Programming Considerations......................................................................................................58
Rev. 1.00
3
May 06, 2016
HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
Timer Modules – TM........................................................................................... 59
Introduction.................................................................................................................................59
TM Operation..............................................................................................................................59
TM Clock Source.........................................................................................................................60
TM Interrupts...............................................................................................................................60
TM External Pins.........................................................................................................................60
TM Input/Output Pin Selection....................................................................................................61
Programming Considerations......................................................................................................62
Standard Type TM – STM................................................................................... 63
Standard TM Operation...............................................................................................................63
Standard Type TM Register Description.....................................................................................63
Standard Type TM Operating Modes..........................................................................................68
Periodic Type TM – PTM..................................................................................... 78
Periodic TM Operation................................................................................................................78
Periodic Type TM Register Description.......................................................................................78
Periodic Type TM Operating Modes............................................................................................83
Analog to Digital Converter – ADC.................................................................... 92
A/D Overview..............................................................................................................................92
A/D Converter Register Description............................................................................................93
A/D Converter Data Registers – SADOL, SADOH......................................................................93
A/D Converter Control Registers – SADC0, SADC1, SADC2, PASR.........................................93
A/D Operation.............................................................................................................................96
A/D Reference Voltage................................................................................................................97
A/D Converter Input Signal.........................................................................................................98
Conversion Rate and Timing Diagram........................................................................................98
Summary of A/D Conversion Steps.............................................................................................99
Programming Considerations....................................................................................................100
A/D Transfer Function...............................................................................................................100
A/D Programming Examples.....................................................................................................101
Interrupts........................................................................................................... 103
Interrupt Registers.....................................................................................................................103
Interrupt Operation....................................................................................................................106
External Interrupt.......................................................................................................................107
Multi-function Interrupt..............................................................................................................108
A/D Converter Interrupt.............................................................................................................108
Time Base Interrupts.................................................................................................................108
EEPROM Interrupt....................................................................................................................109
TM Interrupts............................................................................................................................. 110
Interrupt Wake-up Function...................................................................................................... 110
Programming Considerations.................................................................................................... 110
Configuration Option........................................................................................ 111
Application Circuits.......................................................................................... 111
Rev. 1.00
4
May 06, 2016
HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
Instruction Set................................................................................................... 112
Introduction............................................................................................................................... 112
Instruction Timing...................................................................................................................... 112
Moving and Transferring Data................................................................................................... 112
Arithmetic Operations................................................................................................................ 112
Logical and Rotate Operation................................................................................................... 113
Branches and Control Transfer................................................................................................. 113
Bit Operations........................................................................................................................... 113
Table Read Operations............................................................................................................. 113
Other Operations....................................................................................................................... 113
Instruction Set Summary................................................................................. 114
Table Conventions..................................................................................................................... 114
Instruction Definition........................................................................................ 116
Package Information........................................................................................ 125
8-pin SOP (150mil) Outline Dimensions...................................................................................126
10-pin SOP (150mil) Outline Dimensions.................................................................................127
16-pin NSOP (150mil) Outline Dimensions...............................................................................128
Rev. 1.00
5
May 06, 2016
HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
Note that 8-pin MCU package types are not marketed in the following
countries: UK, Germany, The Netherlands, France and Italy
Features
CPU Features
• Operating Voltage
♦♦
fSYS=4MHz: 1.8V~5.5V
♦♦
fSYS=8MHz: 1.8V~5.5V
• Up to 0.5μs instruction cycle with 8MHz system clock at VDD=5V
• Power down and wake-up functions to reduce power consumption
• Two Oscillators
♦♦
Internal RC – HIRC
♦♦
Internal 32kHz – LIRC
• Fully intergrated internal 4/8MHz oscillator requires no external components
• Multi-mode operation: NORMAL, SLOW, IDLE and SLEEP
• All instructions executed in one or two instruction cycles
• Table read instructions
• 63 powerful instructions
• Up to 2-level subroutine nesting
• Bit manipulation instruction
Peripheral Features
• Flash Program Memory: 1K×14
• RAM Data Memory: 64×8
• EEPROM Memory: 32×8
• Watchdog Timer function
• Up to 14 bidirectional I/O lines
• One pin-shared external interrupt
• Multiple Timer Modules for time measure, compare match output, capture input, PWM output,
single pulse output functions
• Dual Time-Base functions for generation of fixed time interrupt signals
• 4-channel 12-bit resolution A/D converter
• Low voltage reset function
• Package types
Rev. 1.00
♦♦
HT66F303: 16-pin NSOP
♦♦
HT66F302: 8-pin SOP, 10-pin SOP
6
May 06, 2016
HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
General Description
The devices are a Flash Memory type 8-bit high performance RISC architecture microcontroller.
Offering users the convenience of Flash Memory multi-programming features, The devices also
includes a wide range of functions and features. Other memory includes an area of RAM Data
Memory as well as an area of EEPROM memory for storage of non-volatile data such as serial
numbers, calibration data etc.
Analog features include a multi-channel 12-bit A/D converter function. Multiple and extremely
flexible Timer Modules provide timing, pulse generation, capture input, compare match output and
PWM generation functions. Protective features such as an internal Watchdog Timer, Low Voltage
Reset coupled with excellent noise immunity and ESD protection ensure that reliable operation is
maintained in hostile electrical environments.
A full choice of internal oscillator functions are provided including a fully integrated system
oscillator which requires no external components for its implementation.
The inclusion of flexible I/O programming features, Time-Base functions along with many other
features ensure that the devices will find excellent use in applications such as electronic metering,
environmental monitoring, handheld instruments, household appliances, electronically controlled
tools, motor driving in addition to many others.
Selection Table
Most features are common to all devices. The main features distinguishing them are I/O count and
package types. The following table summarises the main features of each device.
Part No.
Program
Data
Data
I/O
Memory Memory EEPROM
A/D
Timer
Module
Time
Stack Package
Base
HT66F302
1K×14
64×8
32×8
8
12-bit×4
10-bit STM×1
10-bit PTM×1
2
2
8/10SOP
HT66F303
1K×14
64×8
32×8
14 12-bit×4
10-bit STM×1
10-bit PTM×1
2
2
16NSOP
Block Diagram
Flash/EEPROM
Programming Circuitry
EEPROM
Data
Memory
Flash
Program
Memory
Watchdog
Timer
Low Voltage
Reset
Time
Bases
8-bit
RISC
MCU
Core
Reset
Circuit
Interrupt
Controller
Internal RC
Oscillators
I/O
Rev. 1.00
RAM Data
Memory
Timer
Modules
7
12-bit A/D
Converter
May 06, 2016
HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
Pin Assignment
VDD/AVDD
1
8
VSS/AVSS
PA7/[PTCK]/[STPB]/RES
PA6/[PTCK]/STPI/[STP]
2
7
3
PA5/[INT]/PTPI
6
PA0/[STPI]/AN0/ICPDA
PA1/AN1/VREFI
4
5
PA2/[INT]/[STCK]/AN2/ICPCK
HT66F302
8 SOP-A
VSS/AVSS
VDD/AVDD
1
10
PA7/[PTCK]/[STPB]/RES
PA6/[PTCK]/STPI/[STP]
2
9
PA0/[STPI]/AN0/ICPDA
3
8
PA5/[INT]/PTPI
PA4/[INT]/PTCK/STP
4
7
PA1/AN1/VREFI
PA2/[INT]/[STCK]/AN2/ICPCK
5
6
PA3/INT/STCK/AN3
HT66F302
10 SOP-A
VDD/AVDD
1
16
VSS/AVSS
PA7/[PTCK]/[STPB]/RES
PA6/[PTCK]/STPI/[STP]
2
15
PA0/[STPI]/AN0/ICPDA
3
14
PA5/[INT]/PTPI
PA4/[INT]/PTCK/STP
NC
4
13
PA1/AN1/VREFI
PA2/[INT]/[STCK]/AN2/ICPCK
5
12
PA3/INT/STCK/AN3
6
11
NC
NC
7
10
OCDSCK
8
9
NC
OCDSDA
HT66V302
16 NSOP-A
PB2/PTPB
1
16
PB3/[PTP]
PB1/[PTCK]/STPB
2
15
PB0/[PTPI]/VREFO
3
14
PB4/[PTPB]
PB5/PTP
PA3/INT/STCK/AN3
4
13
PA4/[INT]/PTCK/STP
PA2/[INT]/[STCK]/AN2/OCDSCK/ICPCK
PA1/AN1/VREFI
5
12
PA5/[INT]/PTPI
6
11
PA0/[STPI]/AN0/OCDSDA/ICPDA
7
10
PA6/[PTCK]/STPI/[STP]
PA7/[PTCK]/[STPB]/RES
VSS/AVSS
8
9
VDD/AVDD
HT66F303/HT66V303
16 NSOP-A
Note: 1. Bracketed pin names indicate non-default pinout remapping locations.
2. If the pin-shared pin functions have multiple outputs simultaneously, the desired pin-shared function is
determined by the corresponding software control bits.
3. AVDD&VDD means the VDD and AVDD are the double bonding. VSS&AVSS means the VSS and
AVSS are the double bonding.
4.The OCDSDA and OCDSCK pins are the OCDS dedicated pins.The HT66V303 is the EV chip for the
16-pin NSOP package device, while the HT66V302 is the EV chip for the 8-pin SOP and 10-pin SOP
package device.
Rev. 1.00
8
May 06, 2016
HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
Pin Description
With the exception of the power pins and some relevant transformer control pins, all pins on the
device can be referenced by their Port name, e.g. PA0, PA1 etc, which refer to the digital I/O
function of the pins. However these Port pins are also shared with other function such as the Analog
to Digital Converter, Timer Module pins etc. The function of each pin is listed in the following table,
however the details behind how each pin is configured is contained in other sections of the datasheet.
HT66F302
Pin Name
PA0/[STPI]/
AN0/ICPDA
PA1/AN1/VREFI
PA2/[INT]/[STCK]/
AN2/ICPCK
PA3/INT/STCK/AN3
PA4/[INT]/PTCK/STP
PA5/[INT]/PTPI
Rev. 1.00
Function
OPT
I/T
O/T
PA0
PAWU
PAPU
PASR
Description
ST
CMOS
STPI
PASR
IFS0
ST
—
STM input
—
ADC input channel 0
General purpose I/O. Register enabled pull-high and
wake-up.
AN0
PASR
AN
ICPDA
—
ST
CMOS ICP Address/Data
PA1
PAWU
PAPU
PASR
ST
CMOS
General purpose I/O. Register enabled pull-high and
wake-up.
AN1
PASR
AN
—
ADC input channel 1
VREFI
PASR
AN
—
ADC VREF Input
PA2
PAWU
PAPU
PASR
ST
CMOS
INT
PASR
IFS0
ST
—
External interrupt input
STM clock input
General purpose I/O. Register enabled pull-high and
wake-up
STCK
IFS0
ST
—
AN2
PASR
AN
—
ADC input channel 2
ICPCK
—
ST
—
ICP Clock pin
PA3
PAWU
PAPU
PASR
ST
CMOS
INT
PASR
IFS0
ST
—
External interrupt input
STCK
IFS0
ST
—
STM clock input
AN3
PASR
AN
—
ADC input channel 3
PA4
PAWU
PAPU
PASR
ST
CMOS
INT
PASR
IFS0
ST
—
External interrupt input
PTCK
PASR
IFS0
ST
—
PTM clock input
STP
PASR
—
CMOS STM output
PA5
PAWU
PAPU
ST
CMOS
General purpose I/O. Register enabled pull-high and
wake-up.
General purpose I/O. Register enabled pull-high and
wake-up.
General purpose I/O. Register enabled pull-high and
wake-up.
INT
IFS0
ST
—
External interrupt input
PTPI
IFS0
ST
—
PTM input
9
May 06, 2016
HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
Pin Name
PA6/[PTCK]/STPI/
[STP]
PA7/[PTCK]/[STPB]/
RES
Function
OPT
I/T
O/T
PA6
PAWU
PAPU
PASR
Description
ST
CMOS
PTCK
PASR
IFS0
ST
—
PTM clock input
STPI
PASR
IFS0
ST
—
STM input
STP
PASR
—
CMOS STM output
PA7
PAWU
PAPU
PASR
ST
CMOS
PTCK
PASR
IFS0
—
—
General purpose I/O. Register enabled pull-high and
wake-up.
General purpose I/O. Register enabled pull-high and
wake-up.
PTM clock input
STPB
PASR
ST
RES
RSTC
ST
CMOS STM inverting output
—
External reset input
VDD
VDD
—
PWR
—
Digital positive power supply
AVDD
AVDD
—
PWR
—
Analog positive power supply
VSS
VSS
—
PWR
—
Digital negative power supply
AVSS
AVSS
—
PWR
—
Analog negative power supply
OCDSDA
OCDSDA
—
ST
OCDSCK
OCDSCK
—
ST
—
Function
OPT
I/T
O/T
PA0
PAWU
PAPU
PASR
ST
CMOS
STPI
PASR
IFS0
ST
—
STM input
AN0
PASR
AN
—
ADC input channel 0
OCDSDA
—
ST
CMOS OCDS Address/Data, for EV chip only
ICPDA
—
ST
CMOS ICP Address/Data
PA1
PAWU
PAPU
PASR
ST
CMOS
CMOS OCDS Address/Data, for EV chip only
OCDS Clock pin, for EV chip only
HT66F303
Pin Name
PA0/[STPI]/AN0/
OCDSDA/ICPDA
PA1/AN1/VREFI
PA2/[INT]/[STCK]/AN2
/OCDSCK/ICPCK
Rev. 1.00
Description
General purpose I/O. Register enabled pull-high and
wake-up.
General purpose I/O. Register enabled pull-high and
wake-up.
AN1
PASR
AN
—
ADC input channel 1
VREFI
PASR
AN
—
ADC VREF Input
PA2
PAWU
PAPU
PASR
ST
CMOS
INT
PASR
IFS0
ST
—
External interrupt input
General purpose I/O. Register enabled pull-high and
wake-up
STCK
IFS0
ST
—
STM clock input
AN2
PASR
AN
—
ADC input channel 2
OCDSCK
—
ST
—
OCDS Clock pin, for EV chip only
ICPCK
—
ST
—
ICP Clock pin
10
May 06, 2016
HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
Pin Name
PA3/INT/STCK/AN3
PA4/[INT]/PTCK/STP
PA5/[INT]/PTPI
PA6/[PTCK]/STPI/
[STP]
PA7/[PTCK]/[STPB]/
RES
PB0/[PTPI]/VREFO
PB1/[PTCK]/STPB
PB2/PTPB
PB3/[PTP]
PB4/[PTPB]
Rev. 1.00
Function
OPT
I/T
O/T
PA3
PAWU
PAPU
PASR
ST
CMOS
INT
PASR
IFS0
ST
—
Description
General purpose I/O. Register enabled pull-high and
wake-up.
External interrupt input
STCK
IFS0
ST
—
STM clock input
AN3
PASR
AN
—
ADC input channel 3
PA4
PAWU
PAPU
PASR
ST
CMOS
INT
PASR
IFS0
ST
—
External interrupt input
PTCK
PASR
IFS0
ST
—
PTM clock input
STP
PASR
—
CMOS STM output
PA5
PAWU
PAPU
ST
CMOS
General purpose I/O. Register enabled pull-high and
wake-up.
General purpose I/O. Register enabled pull-high and
wake-up.
INT
IFS0
ST
—
External interrupt input
PTPI
IFS0
ST
—
PTM input
PA6
PAWU
PAPU
PASR
ST
CMOS
PTCK
PASR
IFS0
ST
—
PTM clock input
STPI
PASR
IFS0
ST
—
STM input
STP
PASR
—
CMOS STM output
PA7
PAWU
PAPU
PASR
ST
CMOS
PTCK
PASR
IFS0
ST
—
STPB
PASR
—
RES
RSTC
ST
PB0
PBPU
PBSR
ST
PTPI
PBSR
IFS0
ST
—
PTM input
VREFO
PBSR
—
AN
ADC reference voltage output
PB1
PBPU
PBSR
ST
PTCK
PBSR
IFS0
—
STPB
PBSR
ST
CMOS STM inverting output
PB2
PBPU
PBSR
ST
CMOS General purpose I/O. Register enabled pull-high
PTPB
—
ST
CMOS PTM inverting output
PB3
PBPU
PBSR
ST
CMOS General purpose I/O. Register enabled pull-high
PTP
PBSR
—
CMOS PTM output
PB4
PBPU
PBSR
ST
CMOS General purpose I/O. Register enabled pull-high
PTPB
PBSR
—
CMOS PTM inverting output
General purpose I/O. Register enabled pull-high and
wake-up.
General purpose I/O. Register enabled pull-high and
wake-up.
PTM clock input
CMOS STM inverting output
—
External reset input
CMOS General purpose I/O. Register enabled pull-high
CMOS General purpose I/O. Register enabled pull-high
—
11
PTM clock input
May 06, 2016
HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
Pin Name
PB5/PTP
Function
OPT
I/T
PB5
PBPU
PBSR
O/T
Description
ST
CMOS General purpose I/O. Register enabled pull-high
CMOS PTM output
PTP
PBSR
—
VDD
VDD
—
PWR
—
Digital positive power supply
AVDD
AVDD
—
PWR
—
Analog positive power supply
VSS
VSS
—
PWR
—
Digital negative power supply
AVSS
AVSS
—
PWR
—
Analog negative power supply
Legend: I/T: Input type;
O/T: Output type
OP: Optional by register option
PWR: Power;
ST: Schmitt Trigger input
CMOS: CMOS output;
AN: Analog signal pin
VDD is the device power supply while AVDD is the ADC power supply. The AVDD pin is bonded
together internally with VDD.
VSS is the device ground pin while AVSS is the ADC ground pin. The AVSS pin is bonded together
internally with VSS.
As the Pin Description Summary table applies to the package type with the most pins, not all of the above
listed pins may be present on package types with smaller numbers of pins.
Absolute Maximum Ratings
Supply Voltage.....................................................................................................VSS-0.3V to VSS+6.0V
Input Voltage.......................................................................................................VSS-0.3V to VDD+0.3V
Storage Temperature...................................................................................................... -50°C to 125°C
Operating Temperature.....................................................................................................-40°C to 85°C
IOL Total.........................................................................................................................................80mA
IOH Total........................................................................................................................................ -80mA
Total Power Dissipation.............................................................................................................500mW
Note: These are stress ratings only. Stresses exceeding the range specified under “Absolute
Maximum Ratings” may cause substantial damage to the device. Functional operation of
the devices at other conditions beyond those listed in the specification is not implied and
prolonged exposure to extreme conditions may affect device reliability.
Rev. 1.00
12
May 06, 2016
HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
D.C. Characteristics
Ta=25°C
Symbol
VDD
Parameter
Operating Voltage (HIRC)
Test Conditions
IDD
SLEEP0 Mode Standby Current
SLEEP1 Mode Standby Current
ISTB
IDLE0 Mode Standby Current
Max.
Unit
V
1.8
—
5.5
1.8
—
5.5
V
No load, all peripherals off,
fSYS=fHIRC=4MHz
—
0.5
1.0
mA
—
1.2
1.8
mA
No load, all peripherals off,
fSYS=fHIRC=8MHz
—
1.0
2.0
mA
—
2.0
3.0
mA
No load, all peripherals off,
fSYS=fLIRC=32kHz
—
20
30
μA
—
30
60
μA
No load, all peripherals off,
WDT off
—
0.2
0.8
μA
—
0.5
1.0
μA
No load, all peripherals off,
WDT on
—
1.3
5.0
μA
—
2.2
10.0
μA
No load, all peripherals off,
fSUB on
—
1.3
3
μA
—
5
10
μA
No load, all peripherals off,
fSUB on, fSYS=fHIRC=4MHz
—
0.4
0.8
mA
—
0.5
1.0
mA
—
0.8
1.6
mA
5V
No load, all peripherals off,
fSUB on, fSYS=fHIRC=8MHz
—
1.0
2.0
mA
5V
3V
3V
5V
3V
5V
3V
5V
3V
5V
3V
IDLE1 Mode Standby Current
Typ.
fSYS=fHIRC=4MHz
5V
Operating Current (LIRC)
Min.
fSYS=fHIRC=8MHz
—
3V
Operating Crrent (HIRC)
Conditions
VDD
5V
3V
VLVR
Low Voltage Reset Voltage
—
LVR enable, voltage select 1.7V
- 5%
1.7
+ 5%
V
VBG
Bandgap Reference Voltage
3V
—
-5%
1.0
+5%
V
ILVR
Additional Current for LVR Enable
Input Low Voltage for I/O Ports or
Input Pins except RES Pin
5V
VIL
—
Input Low Voltage for RES Pin
VIH
IOL
IOH
RPH
—
6
8
—
10
15
—
0
—
1.5
V
—
0
—
0.2VDD
V
—
—
0
—
0.4VDD
V
Input High Voltage for I/O Ports or
Input Pins except RES Pin
5V
—
3.5
—
5
V
—
—
0.8VDD
—
VDD
V
Input High Voltage for RES Pin
—
—
0.9VDD
—
VDD
V
1.8V VOL=0.1VDD
7
14
─
mA
3V
VOL=0.1VDD
18
36
─
mA
5V
VOL=0.1VDD
40
80
─
mA
3V
VOH=0.9VDD
-3
-6
─
mA
5V
VOH=0.9VDD
-7
-14
─
mA
3V
LVPU=0
20
60
100
kΩ
5V
LVPU=0
10
30
50
kΩ
3V
LVPU=1
6.67
15
23
kΩ
5V
LVPU=1
3.5
7.5
12
kΩ
I/O Port Sink Current
I/O Port Source Current
Pull-high Resistance for I/O Ports
Rev. 1.00
3V
5V
LVR disable → LVR enable
13
μA
May 06, 2016
HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
A.C. Characteristics
Ta=25°C
Symbol
fSYS
Test Conditions
Parameter
System Clock (HIRC)
System Clock (LIRC)
fHIRC
fLIRC
System Clock (LIRC)
Max.
Unit
—
—
4
—
MHz
—
—
8
—
MHz
—
—
32
—
kHz
-1%
4
+1%
1.8V~5.5V
1.8V~5.5V
1.8V~5.5V
Ta=25°C
-2%
4
-2.5%
4
Ta=-40°C~85°C
-3%
8
-3%
1.8V~5.5V Ta=-40°C~85°C
2.2V~5.5V
3V/5V
8MHz Trimmed HIRC Frequency
Typ.
Conditions
3V/5V
4MHz Trimmed HIRC Frequency
Min.
VDD
2.2V~5.5V
Ta=-40°C~85°C
Ta=25°C
+2%
+2.5% MHz
-5%
4
+5%
Ta=25°C
-1%
8
+1%
Ta=-40°C~85°C
-2%
8
-2.5%
8
Ta=25°C
+2%
+2.5% MHz
Ta=-40°C~85°C
-3%
8
-3%
1.8V~5.5V Ta=-40°C~85°C
-5%
8
-5%
1.8V~5.5V Ta=-40°C~85°C
8
32
50
kHz
tINT
External Interrupt Minimum Pulse Width
—
—
0.3
─
─
μs
tTimer
xTCK, xTPI Input Pulse Width
—
—
0.3
─
─
μs
tRES
External Reset Low Pulse Width
—
—
10
─
─
μs
tEERD
EEPROM Read Time
—
—
─
2
4
tSYS
tEEWR
EEPROM Write Time
—
—
─
2
7.5
ms
System Reset Delay Time
(POR Reset, LVR Hardware Reset, LVR
Software Reset, WDT Software Reset)
—
—
25
50
150
ms
System Reset Delay Time
(Reset Pin Reset, WDT Time-out Hardware
Cold Reset)
—
—
8.3
16.7
50
ms
tRSTD
System Start-up Timer Period
(Wake-up from HALT, fSYS Off at HALT,
Reset Pin Reset)
tSST
System Start-up Timer Period
(Wake-up from HALT, fSYS On at HALT
State)
System Start-up Timer Period
(WDT Time-out Hardware Cold Reset)
—
fSYS=fH~fH / 64,
fH=fHIRC
16
—
—
tHIRC
—
fSYS=fSUB=fLIRC
2
—
—
tLIRC
—
fSYS=fH~fH / 64,
fSYS=fHIRC
2
—
—
tH
—
fSYS=fLIRC
2
—
—
tSUB
0
—
—
tH
—
—
150
μs
120
600
850
μs
—
tBGS
VBG Turn on Stable Time
—
tLVR
Minimum Low Voltage width to Reset
—
—
No load
—
Note: 1. tSYS=1/fSYS
2. To maintain the accuracy of the internal HIRC oscillator frequency, a 0.1μF decoupling capacitor should
be connected between VDD and VSS and located as close to the device as possible.
Rev. 1.00
14
May 06, 2016
HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
ADC Electrical Characteristics
Symbol
Parameter
Ta=25°C
Test Conditions
VDD
Conditions
Min.
Typ.
Max.
Unit
VDD
Operating Voltage
—
—
1.8
—
5.5
V
VADI
Input Voltage
—
—
0
—
VREF
V
VREF
Reference Voltage
—
—
1.8
—
VDD
V
-3
—
+3
LSB
-4
—
+4
LSB
—
0.8
1.0
mA
—
0.2
0.4
mA
—
0.3
0.6
mA
1.8V ≤ VDD ≤ 2.0V
2.0
—
10
μs
2.0V ≤ VDD ≤ 5.5V
DNL
Differential Nonlinearity
VREF=AVDD=VDD,
1.8V
tADCK=2.0μs
3V
5V
1.8V
INL
Integral Nonlinearity
3V
5V
VREF=AVDD=VDD,
tADCK=0.5μs
VREF=AVDD=VDD,
tADC=2.0μs
VREF=AVDD=VDD,
tADC=0.5μs
1.8V
IADC
Additional Current for ADC Enable
3V
No load (tADCK=0.5μs)
5V
tADCK
Clock Period
—
0.5
—
10
μs
tON2ST
ADC on to ADC Start
—
—
4
—
—
μs
tADC
Conversion Time
(Include ADC Sample and Hold Time)
—
—
—
16
—
tADCK
IPGA
Additional Current for PGA Enable
1.8V No load
VCM
VOR
Ga
Rev. 1.00
PGA Common Mode Voltage Range
PGA Maximum Output Voltage Range
PGA Gain Accuracy
3V
No load
5V
No load
—
160
250
μA
—
180
300
μA
—
250
350
μA
1.8V
—
1
—
AVDD-0.4
V
2.2V
—
1
—
AVDD-0.4
V
3V
—
1
—
AVDD-0.4
V
5V
—
1
—
AVDD-0.4
V
1.8V
—
VSS+0.1
—
VDD–0.1
V
2.2V
—
VSS+0.1
—
VDD–0.1
V
3V
—
VSS+0.1
—
VDD–0.1
V
5V
—
VSS+0.1
—
VDD–0.1
V
—
—
-5
—
+5
%
15
May 06, 2016
HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
Power on Reset Electrical Characteristics
Ta=25°C
Symbol
Test Conditions
Parameter
VDD
Conditions
Min.
Typ.
Max.
Unit
VPOR
VDD start voltage to ensure power-on reset
—
—
—
—
100
mV
RRPOR
VDD rising rate to ensure power-on reset
—
—
0.035
—
—
V/ms
tPOR
Minimum time for VDD stays at VPOR to
ensure power-on reset
—
—
1
—
—
ms
VDD
tPOR
RRPOR
VPOR
Time
System Architecture
A key factor in the high-performance features of the Holtek range of microcontrollers is attributed
to their internal system architecture. The range of devices take advantage of the usual features found
within RISC microcontrollers providing increased speed of operation and Periodic performance. The
pipelining scheme is implemented in such a way that instruction fetching and instruction execution
are overlapped, hence instructions are effectively executed in one cycle, with the exception of branch
or call instructions. An 8-bit wide ALU is used in practically all instruction set operations, which
carries out arithmetic operations, logic operations, rotation, increment, decrement, branch decisions,
etc. The internal data path is simplified by moving data through the Accumulator and the ALU.
Certain internal registers are implemented in the Data Memory and can be directly or indirectly
addressed. The simple addressing methods of these registers along with additional architectural
features ensure that a minimum of external components is required to provide a functional I/O and
A/D control system with maximum reliability and flexibility. This makes the devices suitable for
low-cost, high-volume production for controller applications.
Clocking and Pipelining
The main system clock, derived from either a HIRC or LIRC oscillator is subdivided into four
internally generated non-overlapping clocks, T1~T4. The Program Counter is incremented at the
beginning of the T1 clock during which time a new instruction is fetched. The remaining T2~T4
clocks carry out the decoding and execution functions. In this way, one T1~T4 clock cycle forms
one instruction cycle. Although the fetching and execution of instructions takes place in consecutive
instruction cycles, the pipelining structure of the microcontroller ensures that instructions are
effectively executed in one instruction cycle. The exception to this are instructions where the
contents of the Program Counter are changed, such as subroutine calls or jumps, in which case the
instruction will take one more instruction cycle to execute.
Rev. 1.00
16
May 06, 2016
HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
fSYS
(S�stem Clock)
Phase Clock T1
Phase Clock T�
Phase Clock T3
Phase Clock T4
Program Counter
Pipelining
PC
PC+1
PC+�
Fetch Inst. (PC)
Execute Inst. (PC-1)
Fetch Inst. (PC+1)
Execute Inst. (PC)
Fetch Inst. (PC+�)
Execute Inst. (PC+1)
System Clock and Pipelining
For instructions involving branches, such as jump or call instructions, two machine cycles are
required to complete instruction execution. An extra cycle is required as the program takes one
cycle to first obtain the actual jump or call address and then another cycle to actually execute the
branch. The requirement for this extra cycle should be taken into account by programmers in timing
sensitive applications.
1
�OV A�[1�H]
�
CALL DELAY
3
CPL [1�H]
4
:
5
:
� DELAY: NOP
Fetch Inst. 1
Execute Inst. 1
Fetch Inst. �
Execute Inst. �
Fetch Inst. 3
Flush Pipeline
Fetch Inst. �
Execute Inst. �
Fetch Inst. 7
Instruction Fetching
Program Counter
During program execution, the Program Counter is used to keep track of the address of the
next instruction to be executed. It is automatically incremented by one each time an instruction
is executed except for instructions, such as “JMP” or “CALL” that demand a jump to a nonconsecutive Program Memory address. Only the lower 8 bits, known as the Program Counter Low
Register, are directly addressable by the application program.
When executing instructions requiring jumps to non-consecutive addresses such as a jump
instruction, a subroutine call, interrupt or reset, etc., the microcontroller manages program control
by loading the required address into the Program Counter. For conditional skip instructions, once
the condition has been met, the next instruction, which has already been fetched during the present
instruction execution, is discarded and a dummy cycle takes its place while the correct instruction is
obtained.
Program Counter
Program Counter High byte
PCL Register
PC9~PC8
PCL7~PCL0
The lower byte of the Program Counter, known as the Program Counter Low register or PCL, is
available for program control and is a readable and writeable register. By transferring data directly
into this register, a short program jump can be executed directly, however, as only this low byte is
available for manipulation, the jumps are limited to the present page of memory, that is 256 locations.
When such program jumps are executed it should also be noted that a dummy cycle will be inserted.
Manipulating the PCL register may cause program branching, so an extra cycle is needed to pre-fetch.
Rev. 1.00
17
May 06, 2016
HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
Stack
This is a special part of the memory which is used to save the contents of the Program Counter
only. The stack is neither part of the data nor part of the program space, and is neither readable nor
writeable. The activated level is indexed by the Stack Pointer, and is neither readable nor writeable.
At a subroutine call or interrupt acknowledge signal, the contents of the Program Counter are pushed
onto the stack. At the end of a subroutine or an interrupt routine, signaled by a return instruction,
RET or RETI, the Program Counter is restored to its previous value from the stack. After a device
reset, the Stack Pointer will point to the top of the stack.
If the stack is full and an enabled interrupt takes place, the interrupt request flag will be recorded
but the acknowledge signal will be inhibited. When the Stack Pointer is decremented, by RET or
RETI, the interrupt will be serviced. This feature prevents stack overflow allowing the programmer
to use the structure more easily. However, when the stack is full, a CALL subroutine instruction can
still be executed which will result in a stack overflow. Precautions should be taken to avoid such
cases which might cause unpredictable program branching. If the stack is overflow, the first Program
Counter save in the stack will be lost.
Program Counter
Top of Stack
Stack
Pointer
Stack Level 1
Stack Level �
Program �emor�
Bottom of Stack
Arithmetic and Logic Unit – ALU
The arithmetic-logic unit or ALU is a critical area of the microcontroller that carries out arithmetic
and logic operations of the instruction set. Connected to the main microcontroller data bus, the ALU
receives related instruction codes and performs the required arithmetic or logical operations after
which the result will be placed in the specified register. As these ALU calculation or operations may
result in carry, borrow or other status changes, the status register will be correspondingly updated to
reflect these changes. The ALU supports the following functions:
• Arithmetic operations: ADD, ADDM, ADC, ADCM, SUB, SUBM, SBC, SBCM, DAA
• Logic operations: AND, OR, XOR, ANDM, ORM, XORM, CPL, CPLA
• Rotation: RRA, RR, RRCA, RRC, RLA, RL, RLCA, RLC
• Increment and Decrement: INCA, INC, DECA, DEC
• Branch decision: JMP, SZ, SZA, SNZ, SIZ, SDZ, SIZA, SDZA, CALL, RET, RETI
Rev. 1.00
18
May 06, 2016
HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
Flash Program Memory
The Program Memory is the location where the user code or program is stored. For the device the
Program Memory is Flash type, which means it can be programmed and re-programmed a large
number of times, allowing the user the convenience of code modification on the same device. By
using the appropriate programming tools, the Flash device offers users the flexibility to conveniently
debug and develop their applications while also offering a means of field programming and
updating.
Structure
The Program Memory has a capacity of 1K×14 bits. The Program Memory is addressed by the
Program Counter and also contains data, table information and interrupt entries. Table data, which can
be setup in any location within the Program Memory, is addressed by a separate table pointer register.
0000H
Reset
0004H
Interrupt Vector
0018H
001CH
03FFH
14 bits
Program Memory Structure
Special Vectors
Within the Program Memory, certain locations are reserved for the reset and interrupts. The location
000H is reserved for use by the device reset for program initialisation. After a device reset is
initiated, the program will jump to this location and begin execution.
Look-up Table
Any location within the Program Memory can be defined as a look-up table where programmers can
store fixed data. To use the look-up table, the table pointer must first be setup by placing the address
of the look up data to be retrieved in the table pointer register, TBLP. This register defines the total
address of the look-up table.
After setting up the table pointer, the table data can be retrieved from the Program Memory using
the “TABRD[m]” or “TABRDL[m]” instructions, respectively. When the instruction is executed,
the lower order table byte from the Program Memory will be transferred to the user defined
Data Memory register [m] as specified in the instruction. The higher order table data byte from
the Program Memory will be transferred to the TBLH special register. Any unused bits in this
transferred higher order byte will be read as “0”.
Rev. 1.00
19
May 06, 2016
HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
The accompanying diagram illustrates the addressing data flow of the look-up table.
  
Table Program Example
The following example shows how the table pointer and table data is defined and retrieved from the
microcontroller. This example uses raw table data located in the Program Memory which is stored
there using the ORG statement. The value at this ORG statement is “300H” which refers to the start
address of the last page within the 1K words Program Memory of the device. The table pointer is
setup here to have an initial value of “06H”. This will ensure that the first data read from the data
table will be at the Program Memory address “306H” or 6 locations after the start of the last page.
Note that the value for the table pointer is referenced to the first address of the present page if the
“TABRDC [m]” instruction is being used. The high byte of the table data which in this case is equal
to zero will be transferred to the TBLH register automatically when the “TABRDL [m]” instruction
is executed.
Because the TBLH register is a read-only register and cannot be restored, care should be taken
to ensure its protection if both the main routine and Interrupt Service Routine use table read
instructions. If using the table read instructions, the Interrupt Service Routines may change the
value of the TBLH and subsequently cause errors if used again by the main routine. As a rule it is
recommended that simultaneous use of the table read instructions should be avoided. However, in
situations where simultaneous use cannot be avoided, the interrupts should be disabled prior to the
execution of any main routine table-read instructions. Note that all table related instructions require
two instruction cycles to complete their operation.
Table Read Program Example
tempreg1 db ? ; temporary register #1
tempreg2 db ? ; temporary register #2
:
:
mov a,06h ; initialise low table pointer - note that this address
mov tblp,a ; is referenced
:
:
tabrdl tempreg1 ; transfers value in table referenced by table pointer data at program
; memory address “306H” transferred to tempreg1 and TBLH
dec tblp ; reduce value of table pointer by one
tabrdl tempreg2 ; transfers value in table referenced by table pointer data at program
; memory address “305H” transferred to tempreg2 and TBLH in this
; example the data “1AH” is transferred to tempreg1 and data “0FH” to
; register tempreg2
:
:
org 300h; sets initial address of program memory
dc 00Ah, 00Bh, 00Ch, 00Dh, 00Eh, 00Fh, 01Ah, 01Bh
:
:
Rev. 1.00
20
May 06, 2016
HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
In Circuit Programming
The provision of Flash type Program Memory provides the user with a means of convenient and easy
upgrades and modifications to their programs on the same device. As an additional convenience,
Holtek has provided a means of programming the microcontroller in-circuit using a 4-pin interface.
This provides manufacturers with the possibility of manufacturing their circuit boards complete with
a programmed or un-programmed microcontroller, and then programming or upgrading the program
at a later stage. This enables product manufacturers to easily keep their manufactured products
supplied with the latest program releases without removal and re-insertion of the device.
Holtek Writer Pins
MCU Programming Pins
ICPDA
PA0
Programming Serial Data/Address
Pin Description
ICPCK
PA2
Programming Clock
VDD
VDD
Power Supply
VSS
VSS
Ground
The Program Memory and EEPROM data memory can both be programmed serially in-circuit using
this 4-wire interface. Data is downloaded and uploaded serially on a single pin with an additional
line for the clock. Two additional lines are required for the power supply and ground. The technical
details regarding the in-circuit programming of the device are beyond the scope of this document
and will be supplied in supplementary literature.
Writer Connector
Signals
�CU Programming
Pins
Writer_VDD
VDD
ICPDA
PA0
ICPCK
PA�
Writer_VSS
VSS
*
*
To other Circuit
Note: * may be resistor or capacitor. The resistance of * must be greater than 1kΩ or the capacitance
of * must be less than 1nF.
On-Chip Debug Support – OCDS
There is an EV chip which is used to emulate the HT66F302/HT66F303 devices. This EV chip
device also provides an “On-Chip Debug” function to debug the device during the development
process. The EV chip and the actual MCU device are almost functionally compatible except for
the “On-Chip Debug” function. Users can use the EV chip device to emulate the real chip device
behavior by connecting the OCDSDA and OCDSCK pins to the Holtek HT-IDE development tools.
The OCDSDA pin is the OCDS Data/Address input/output pin while the OCDSCK pin is the OCDS
clock input pin. When users use the EV chip for debugging, other functions which are shared with
the OCDSDA and OCDSCK pins in the actual MCU device will have no effect in the EV chip.
However, the two OCDS pins which are pin-shared with the ICP programming pins are still used as
the Flash Memory programming pins for ICP. For a more detailed OCDS description, refer to the
corresponding document named “Holtek e-Link for 8-bit MCU OCDS User’s Guide”.
Holtek e-Link Pins
Rev. 1.00
EV Chip Pins
Pin Description
OCDSDA
OCDSDA
OCDSCK
OCDSCK
On-chip Debug Support Data/Address input/output
VDD
VDD
Power Supply
VSS
VSS
Ground
On-chip Debug Support Clock input
21
May 06, 2016
HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
RAM Data Memory
The Data Memory is a volatile area of 8-bit wide RAM internal memory and is the location where
temporary information is stored.
Structure
Divided into two sections, the first of these is an area of RAM, known as the Special Function Data
Memory. Here are located registers which are necessary for correct operation of the device. Many
of these registers can be read from and written to directly under program control, however, some
remain protected from user manipulation. The second area of Data Memory is known as the General
Purpose Data Memory, which is reserved for general purpose use. All locations within this area are
read and write accessible under program control.
The overall Data Memory is subdivided into two banks. The Special Purpose Data Memory registers
are accessible in all banks, with the exception of the EEC register at address 40H, which is only
accessible in Bank 1. Switching between the different Data Memory banks is achieved by setting the
Bank Pointer to the correct value. The start address of the Data Memory for the device is the address
00H.
General Purpose Data Memory
There is 64 bytes of general purpose data memory which are arranged in Bank 0. All microcontroller
programs require an area of read/write memory where temporary data can be stored and retrieved for
use later. It is this area of RAM memory that is known as General Purpose Data Memory. This area
of Data Memory is fully accessible by the user programing for both reading and writing operations.
By using the bit operation instructions individual bits can be set or reset under program control
giving the user a large range of flexibility for bit manipulation in the Data Memory.
Special Purpose Data Memory
This area of Data Memory is where registers, necessary for the correct operation of the
microcontroller, are stored. Most of the registers are both readable and writeable but some are
protected and are readable only, the details of which are located under the relevant Special Function
Register section. Note that for locations that are unused, any read instruction to these addresses will
return the value “00H”.
Rev. 1.00
Device
Capacity
Bank 0
Bank 1
HT66F302/HT66F303
64×8
40H~7FH
40H EEC register only
22
May 06, 2016
HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
20H
21H
22H
23H
24H
25H
26H
27H
28H
29H
2AH
2BH
2CH
2DH
STATUS
SMOD
LVPUC
INTEG
INTC0
INTC1
2EH
2FH
30H
31H
32H
33H
34H
35H
36H
37H
38H
39H
3AH
MFI0
MFI1
PA
PAC
PAPU
PAWU
IFS0
WDTC
TBC
SMOD1
LVRC
EEA
EED
Bank 0 Bank 1
SADOL
SADOH
SADC0
SADC1
SADC2
RSTC
PASR
STMC0
STMC1
STMDL
STMDH
STMAL
STMAH
PTMC0
PTMC1
PTMDL
PTMDH
PTMAL
PTMAH
PTMRPL
PTMRPH
~
00H
01H
02H
03H
04H
05H
06H
07H
08H
09H
0AH
0BH
0CH
0DH
0EH
0FH
10H
11H
12H
13H
14H
15H
16H
17H
18H
19H
1AH
1BH
1CH
1DH
1EH
1FH
Bank 0~1
IAR0
MP0
IAR1
MP1
BP
ACC
PCL
TBLP
TBLH
3FH
: Unused, read as "00"
: Reserved, cannot be changed
Special Purpose Data Memory Structure – HT66F302
Rev. 1.00
23
May 06, 2016
HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
00H
01H
02H
03H
04H
05H
06H
07H
08H
09H
0AH
0BH
0CH
0DH
0EH
0FH
10H
11H
12H
13H
14H
15H
16H
17H
18H
19H
1AH
1BH
1CH
1DH
1EH
1FH
Bank 0~1
IAR0
MP0
IAR1
MP1
BP
ACC
PCL
TBLP
TBLH
20H
21H
22H
23H
24H
25H
26H
27H
28H
29H
2AH
2BH
2CH
2DH
STATUS
SMOD
LVPUC
INTEG
INTC0
INTC1
Bank 0 Bank 1
SADOL
SADOH
SADC0
SADC1
SADC2
RSTC
PASR
PBSR
STMC0
STMC1
STMDL
STMDH
STMAL
STMAH
2EH
2FH
30H
31H
32H
33H
34H
35H
36H
37H
38H
39H
3AH
~
3FH
MFI0
MFI1
PA
PAC
PAPU
PAWU
IFS0
WDTC
TBC
SMOD1
LVRC
EEA
EED
PB
PBC
PBPU
PTMC0
PTMC1
PTMDL
PTMDH
PTMAL
PTMAH
PTMRPL
PTMRPH
: Unused, read as "00"
Special Purpose Data Memory Structure – HT66F303
40H
EEC
General
Purpose
Data �emor�
Unused
7FH
General Purpose Data Memory
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Cost-Effective 8-Bit Flash MCU with EEPROM
Special Function Register Description
Most of the Special Function Register details will be described in the relevant functional section,
however several registers require a separate description in this section.
Indirect Addressing Registers – IAR0, IAR1
The Indirect Addressing Registers, IAR0 and IAR1, although having their locations in normal RAM
register space, do not actually physically exist as normal registers. The method of indirect addressing
for RAM data manipulation uses these Indirect Addressing Registers and Memory Pointers, in
contrast to direct memory addressing, where the actual memory address is specified. Actions on the
IAR0 and IAR1 registers will result in no actual read or write operation to these registers but rather
to the memory location specified by their corresponding Memory Pointers, MP0 or MP1. Acting as a
pair, IAR0 and MP0 can together access data from Bank 0 while the IAR1 and MP1 register pair can
access data from any bank. As the Indirect Addressing Registers are not physically implemented,
reading the Indirect Addressing Registers indirectly will return a result of “00H” and writing to the
registers indirectly will result in no operation.
Memory Pointers – MP0, MP1
Two Memory Pointers, known as MP0 and MP1 are provided. These Memory Pointers are
physically implemented in the Data Memory and can be manipulated in the same way as normal
registers providing a convenient way with which to address and track data. When any operation to
the relevant Indirect Addressing Registers is carried out, the actual address that the microcontroller
is directed to is the address specified by the related Memory Pointer. MP0, together with Indirect
Addressing Register, IAR0, are used to access data from Bank 0, while MP1 and IAR1 are used to
access data from all banks according to BP register. Direct Addressing can only be used with Bank 0,
all other Banks must be addressed indirectly using MP1 and IAR1.
The following example shows how to clear a section of four Data Memory locations already defined
as locations adres1 to adres4.
Indirect Addressing Program Example
data .section ´data´
adres1 db ?
adres2 db ?
adres3 db ?
adres4 db ?
block db ?
code .section at 0 ´code´
org 00h
start:
mov a,04h ; setup size of block
mov block,a
mov a,offset adres1 ; Accumulator loaded with first RAM address
mov mp0,a ; setup memory pointer with first RAM address
loop:
clr IAR0 ; clear the data at address defined by mp0
inc mp0; increment memory pointer
sdz block ; check if last memory location has been cleared
jmp loop
continue:
The important point to note here is that in the example shown above, no reference is made to specific
Data Memory addresses.
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Cost-Effective 8-Bit Flash MCU with EEPROM
Bank Pointer – BP
For the devices, the Data Memory is divided into two banks, Bank0 and Bank1. Selecting the
required Data Memory area is achieved using the Bank Pointer. Bit 0 of the Bank Pointer is used to
select Data Memory Banks 0~1.
The Data Memory is initialised to Bank 0 after a reset, except for a WDT time-out reset in the Power
Down Mode, in which case, the Data Memory bank remains unaffected. It should be noted that the
Special Function Data Memory is not affected by the bank selection, which means that the Special
Function Registers can be accessed from within any bank. Directly addressing the Data Memory
will always result in Bank 0 being accessed irrespective of the value of the Bank Pointer. Accessing
data from Bank1 must be implemented using Indirect Addressing.
BP Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
—
—
—
DMBP0
R/W
—
—
—
—
—
—
—
R/W
POR
—
—
—
—
—
—
—
0
Bit 7~1
Unimplemented, read as “0”
Bit 0DMBP0: Select Data Memory Banks
0: Bank 0
1: Bank 1
Accumulator – ACC
The Accumulator is central to the operation of any microcontroller and is closely related with
operations carried out by the ALU. The Accumulator is the place where all intermediate results
from the ALU are stored. Without the Accumulator it would be necessary to write the result of
each calculation or logical operation such as addition, subtraction, shift, etc., to the Data Memory
resulting in higher programming and timing overheads. Data transfer operations usually involve
the temporary storage function of the Accumulator; for example, when transferring data between
one user-defined register and another, it is necessary to do this by passing the data through the
Accumulator as no direct transfer between two registers is permitted.
Program Counter Low Register – PCL
To provide additional program control functions, the low byte of the Program Counter is made
accessible to programmers by locating it within the Special Purpose area of the Data Memory. By
manipulating this register, direct jumps to other program locations are easily implemented. Loading
a value directly into this PCL register will cause a jump to the specified Program Memory location,
however, as the register is only 8-bit wide, only jumps within the current Program Memory page are
permitted. When such operations are used, note that a dummy cycle will be inserted.
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Cost-Effective 8-Bit Flash MCU with EEPROM
Look-up Table Registers – TBLP, TBLH
These two special function registers are used to control operation of the look-up table which is
stored in the Program Memory. TBLP is the table pointer and indicate the location where the table
data is located. Its value must be setup before any table read commands are executed. Its value
can be changed, for example using the “INC” or “DEC” instructions, allowing for easy table data
pointing and reading. TBLH is the location where the high order byte of the table data is stored
after a table read data instruction has been executed. Note that the lower order table data byte is
transferred to a user defined location.
Status Register – STATUS
This 8-bit register contains the zero flag (Z), carry flag (C), auxiliary carry flag (AC), overflow flag
(OV), power down flag (PDF), and watchdog time-out flag (TO). These arithmetic/logical operation
and system management flags are used to record the status and operation of the microcontroller.
With the exception of the TO and PDF flags, bits in the status register can be altered by instructions
like most other registers. Any data written into the status register will not change the TO or PDF flag.
In addition, operations related to the status register may give different results due to the different
instruction operations. The TO flag can be affected only by a system power-up, a WDT time-out or
by executing the “CLR WDT” or “HALT” instruction. The PDF flag is affected only by executing
the “HALT” or “CLR WDT” instruction or during a system power-up.
The Z, OV, AC and C flags generally reflect the status of the latest operations.
• C is set if an operation results in a carry during an addition operation or if a borrow does not take
place during a subtraction operation; otherwise C is cleared. C is also affected by a rotate through
carry instruction.
• AC is set if an operation results in a carry out of the low nibbles in addition, or no borrow from
the high nibble into the low nibble in subtraction; otherwise AC is cleared.
• Z is set if the result of an arithmetic or logical operation is zero; otherwise Z is cleared.
• OV is set if an operation results in a carry into the highest-order bit but not a carry out of the
highest-order bit, or vice versa; otherwise OV is cleared.
• PDF is cleared by a system power-up or executing the “CLR WDT” instruction. PDF is set by
executing the “HALT” instruction.
• TO is cleared by a system power-up or executing the “CLR WDT” or “HALT” instruction. TO is
set by a WDT time-out.
In addition, on entering an interrupt sequence or executing a subroutine call, the status register will
not be pushed onto the stack automatically. If the contents of the status registers are important and if
the subroutine can corrupt the status register, precautions must be taken to correctly save it.
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Cost-Effective 8-Bit Flash MCU with EEPROM
STATUS Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
TO
PDF
OV
Z
AC
C
R/W
—
—
R
R
R/W
R/W
R/W
R/W
POR
—
—
0
0
x
x
x
x
"x" unknown
Bit 7~6
Unimplemented, read as “0”
Bit 5TO: Watchdog Time-Out flag
0: After power up or executing the “CLR WDT” or “HALT” instruction
1: A watchdog time-out occurred.
Bit 4PDF: Power down flag
0: After power up or executing the “CLR WDT” instruction
1: By executing the “HALT” instruction
Bit 3OV: Overflow flag
0: No overflow
1: An operation results in a carry into the highest-order bit but not a carry out of the
highest-order bit or vice versa.
Bit 2Z: Zero flag
0: The result of an arithmetic or logical operation is not zero
1: The result of an arithmetic or logical operation is zero
Bit 1AC: Auxiliary flag
0: No auxiliary carry
1: An operation results in a carry out of the low nibbles in addition, or no borrow
from the high nibble into the low nibble in subtraction
Bit 0C: Carry flag
0: No carry-out
1: An operation results in a carry during an addition operation or if a borrow does
not take place during a subtraction operation
C is also affected by a rotate through carry instruction.
EEPROM Data Memory
The devices contain an area of internal EEPROM Data Memory. EEPROM, which stands for
Electrically Erasable Programmable Read Only Memory, is by its nature a non-volatile form of
memory, with data retention even when its power supply is removed. By incorporating this kind
of data memory, a whole new host of application possibilities are made available to the designer.
The availability of EEPROM storage allows information such as product identification numbers,
calibration values, specific user data, system setup data or other product information to be stored
directly within the product microcontroller. The process of reading and writing data to the EEPROM
memory has been reduced to a very trivial affair.
EEPROM Data Memory Structure
The EEPROM Data Memory capacity is 32×8 bits for the devices. Unlike the Program Memory
and RAM Data Memory, the EEPROM Data Memory is not directly mapped and is therefore not
directly accessible in the same way as the other types of memory. Read and Write operations to the
EEPROM are carried out in single byte operations using two address registers and one data register
in Bank 0 and a single control register in Bank 1.
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Cost-Effective 8-Bit Flash MCU with EEPROM
EEPROM Registers
Three registers control the overall operation of the internal EEPROM Data Memory. These are
the address registers, EEA, the data register, EED and a single control register, EEC. As both the
EEA and EED registers are located in all banks, they can be directly accessed in the same way as
any other Special Function Register. The EEC register however, being located in Bank1, cannot be
directly addressed directly and can only be read from or written to indirectly using the MP1 Memory
Pointer and Indirect Addressing Register, IAR1. Because the EEC control register is located at
address 40H in Bank 1, the MP1 Memory Pointer must first be set to the value 40H and the Bank
Pointer register, BP, set to the value, 01H, before any operations on the EEC register are executed.
Register
Name
Bit
7
6
5
4
3
2
1
0
EEA
—
—
—
D4
D3
D2
D1
D0
EED
D7
D6
D5
D4
D3
D2
D1
D0
EEC
—
—
—
—
WREN
WR
RDEN
RD
EEPROM Control Registers List
EEA Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
D4
D3
D2
D1
D0
R/W
—
—
—
R/W
R/W
R/W
R/W
R/W
POR
—
—
—
0
0
0
0
0
Bit 7~5
Unimplemented, read as “0”
Bit 4~0D4~D0: Data EEPROM address
Data EEPROM address bit 4~bit 0
EED Register
Bit
7
6
5
4
3
2
1
0
Name
D7
D6
D5
D4
D3
D2
D1
D0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~0D7~D0: Data EEPROM data
Data EEPROM data bit 7~bit 0
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Cost-Effective 8-Bit Flash MCU with EEPROM
EEC Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
WREN
WR
RDEN
RD
R/W
—
—
—
—
R/W
R/W
R/W
R/W
POR
—
—
—
—
0
0
0
0
Bit 7~4
Unimplemented, read as “0”
Bit 3WREN: Data EEPROM Write Enable
0: Disable
1: Enable
This is the Data EEPROM Write Enable Bit which must be set high before Data
EEPROM write operations are carried out. Clearing this bit to zero will inhibit Data
EEPROM write operations.
Bit 2WR: EEPROM Write Control
0: Write cycle has finished
1: Activate a write cycle
This is the Data EEPROM Write Control Bit and when set high by the application
program will activate a write cycle. This bit will be automatically reset to zero by the
hardware after the write cycle has finished. Setting this bit high will have no effect if
the WREN has not first been set high.
Bit 1RDEN: Data EEPROM Read Enable
0: Disable
1: Enable
This is the Data EEPROM Read Enable Bit which must be set high before Data
EEPROM read operations are carried out. Clearing this bit to zero will inhibit Data
EEPROM read operations.
Bit 0RD: EEPROM Read Control
0: Read cycle has finished
1: Activate a read cycle
This is the Data EEPROM Read Control Bit and when set high by the application
program will activate a read cycle. This bit will be automatically reset to zero by the
hardware after the read cycle has finished. Setting this bit high will have no effect if
the RDEN has not first been set high.
Note: The WREN, WR, RDEN and RD cannot be set to “1” at the same time in one instruction. The
WR and RD cannot be set to “1” at the same time.
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Cost-Effective 8-Bit Flash MCU with EEPROM
Reading Data from the EEPROM
To read data from the EEPROM, the read enable bit, RDEN, in the EEC register must first be set
high to enable the read function. The EEPROM address of the data to be read must then be placed
in the EEA register. If the RD bit in the EEC register is now set high, a read cycle will be initiated.
Setting the RD bit high will not initiate a read operation if the RDEN bit has not been set. When
the read cycle terminates, the RD bit will be automatically cleared to zero, after which the data can
be read from the EED register. The data will remain in the EED register until another read or write
operation is executed. The application program can poll the RD bit to determine when the data is
valid for reading.
Writing Data to the EEPROM
To write data to the EEPROM, the EEPROM address of the data to be written must first be placed
in the EEA register and the data placed in the EED register. Then the write enable bit, WREN,
in the EEC register must first be set high to enable the write function. After this, the WR bit in
the EEC register must be immediately set high to initiate a write cycle. These two instructions
must be executed consecutively. The global interrupt bit EMI should also first be cleared before
implementing any write operations, and then set again after the write cycle has started. Note that
setting the WR bit high will not initiate a write cycle if the WREN bit has not been set. As the
EEPROM write cycle is controlled using an internal timer whose operation is asynchronous to
microcontroller system clock, a certain time will elapse before the data will have been written into
the EEPROM. Detecting when the write cycle has finished can be implemented either by polling the
WR bit in the EEC register or by using the EEPROM interrupt. When the write cycle terminates,
the WR bit will be automatically cleared to zero by the microcontroller, informing the user that the
data has been written to the EEPROM. The application program can therefore poll the WR bit to
determine when the write cycle has ended.
Write Protection
Protection against inadvertent write operation is provided in several ways. After the device is
powered-on the Write Enable bit in the control register will be cleared preventing any write
operations. Also at power-on the Bank Pointer, BP, will be reset to zero, which means that Data
Memory Bank 0 will be selected. As the EEPROM control register is located in Bank 1, this adds a
further measure of protection against spurious write operations. During normal program operation,
ensuring that the Write Enable bit in the control register is cleared will safeguard against incorrect
write operations.
EEPROM Interrupt
The EEPROM write interrupt is generated when an EEPROM write cycle has ended. The EEPROM
interrupt must first be enabled by setting the DEE bit in the relevant interrupt register. When an
EEPROM write cycle ends, the DEF request flag will be set. If the global, EEPROM Interrupt are
enabled and the stack is not full, a subroutine call to the EEPROM Interrupt vector, will take place.
When the EEPROM Interrupt is serviced, the EEPROM Interrupt flag DEF will be automatically
cleared. The EMI bit will also be automatically cleared to disable other interrupts.
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Cost-Effective 8-Bit Flash MCU with EEPROM
Programming Considerations
Care must be taken that data is not inadvertently written to the EEPROM. Protection can be Periodic
by ensuring that the Write Enable bit is normally cleared to zero when not writing. Also the Bank
Pointer could be normally cleared to zero as this would inhibit access to Bank 1where the EEPROM
control register exist. Although certainly not necessary, consideration might be given in the
application program to the checking of the validity of new write data by a simple read back process.
When writing data the WR bit must be set high immediately after the WREN bit has been set high,
to ensure the write cycle executes correctly. The global interrupt bit EMI should also be cleared
before a write cycle is executed and then re-enabled after the write cycle starts. Note that the device
should not enter the IDLE or SLEEP mode until the EEPROM read or write operation is totally
complete. Otherwise, the EEPROM read or write operation will fail.
Programming Examples
Reading data from the EEPROM – polling method
MOV A, EEPROM_ADRES MOV EEA, A
MOV A, 040H MOV MP1, A MOV A, 01H MOV BP, A
SET IAR1.1 SET IAR1.0 BACK:
SZ IAR1.0 JMP BACK
CLR IAR1 CLR BP
MOV A, EED MOV READ_DATA, A
; user defined address
; setup memory pointer MP1
; MP1 points to EEC register
; setup Bank Pointer
; set RDEN bit, enable read operations
; start Read Cycle - set RD bit
; check for read cycle end
; disable EEPROM write
; move read data to register
Writing Data to the EEPROM – polling method
MOV A, EEPROM_ADRES
MOV EEA, A
MOV A, EEPROM_DATA
MOV EED, A
MOV A, 040H MOV MP1, A MOV A, 01H MOV BP, A
CLR EMI
SET IAR1.3 SET IAR1.2 SET EMI
BACK:
SZ IAR1.2 JMP BACK
CLR IAR1 CLR BP
Rev. 1.00
; user defined address
; user defined data
; setup memory pointer MP1
; MP1 points to EEC register
; setup Bank Pointer
; set WREN bit, enable write operations
; start Write Cycle - set WR bit– executed immediately after
; set WREN bit
; check for write cycle end
; disable EEPROM write
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Cost-Effective 8-Bit Flash MCU with EEPROM
Oscillators
Various oscillator options offer the user a wide range of functions according to their various
application requirements. The flexible features of the oscillator functions ensure that the best
optimisation can be achieved in terms of speed and power saving. Oscillator selections and operation
are selected through a combination of configuration options and registers.
Oscillator Overview
In addition to being the source of the main system clock the oscillators also provide clock sources
for the Watchdog Timer and Time Base Interrupts. Two fully integrated internal oscillators, requiring
no external components, are provided to form a wide range of both fast and slow system oscillators.
The higher frequency oscillator provides higher performance but carry with it the disadvantage of
higher power requirements, while the opposite is of course true for the lower frequency oscillator.
With the capability of dynamically switching between fast and slow system clock, the devices have
the flexibility to optimize the performance/power ratio, a feature especially important in power
sensitive portable applications.
Name
Freq.
Internal High Speed RC
Type
HIRC
4, 8MHz
Internal Low Speed RC
LIRC
32kHz
Oscillator Types
System Clock Configurations
There are two methods of generating the system clock, a high speed oscillator and a low speed
oscillator. The high speed oscillator is the internal 4MHz, 8MHz RC oscillator. The low speed
oscillator is the internal 32kHz RC oscillator. Selecting whether the low or high speed oscillator
is used as the system oscillator is implemented using the HLCLK bit and CKS2~CKS0 bits in the
SMOD register and as the system clock can be dynamically selected.
fH/�
fH/4
High Speed Oscillator
fH/8
fH
HIRC
Prescaler
fSYS
fH/1�
fH/3�
fH/�4
Low Speed Oscillator
LIRC
fL
HLCLK
CKS�~CKS0 bits
System Clock Configurations
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Cost-Effective 8-Bit Flash MCU with EEPROM
Internal RC Oscillator – HIRC
The internal RC oscillator is a fully integrated system oscillator requiring no external components.
The internal RC oscillator has two fixed frequency of 4MHz, 8MHz. Device trimming during the
manufacturing process and the inclusion of internal frequency compensation circuits are used to
ensure that the influence of the power supply voltage, temperature and process variations on the
oscillation frequency are minimised. As a result, at a power supply of 5V and at temperature of 25°C
degrees, the fixed oscillation frequency of the HIRC will have a tolerance within 1%.
Internal 32kHz Oscillator – LIRC
The internal 32kHz System Oscillator is the low frequency oscillator. It is a fully integrated
RC oscillator with a typical frequency of 32kHz at 5V, requiring no external components for its
implementation. Device trimming during the manufacturing process and the inclusion of internal
frequency compensation circuits are used to ensure that the influence of the power supply voltage,
temperature and process variations on the oscillation frequency are minimised.
Supplementary Oscillator
The low speed oscillator, in addition to providing a system clock source is also used to provide
a clock source to two other device functions. These are the Watchdog Timer and the Time Base
Interrupts.
Operating Modes and System Clocks
Present day applications require that their microcontrollers have high performance but often still
demand that they consume as little power as possible, conflicting requirements that are especially
true in battery powered portable applications. The fast clocks required for high performance will
by their nature increase current consumption and of course vice-versa, lower speed clocks reduce
current consumption. As Holtek has provided the device with both high and low speed clock sources
and the means to switch between them dynamically, the user can optimise the operation of their
microcontroller to achieve the best performance/power ratio.
System Clocks
The devices have two different clock sources for both the CPU and peripheral function operation. By
providing the user with clock options using register programming, a clock system can be configured
to obtain maximum application performance.
The main system clock, can come from either a high frequency, fH, or a low frequency, fL, and is
selected using the HLCLK bit and CKS2~CKS0 bits in the SMOD register. The high speed system
clock can be sourced from HIRC oscillator. The low speed system clock source can be sourced
from the internal clock LIRC. The other choice, which is a divided version of the high speed system
oscillator has a range of fH/2~fH/64.
There is one additional internal clock for the peripheral circuits, the Time Base clock, fTBC. fTBC is
sourced from the LIRC oscillators. The fTBC clock is used as a source for the Time Base interrupt
functions and for the TMs.
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Cost-Effective 8-Bit Flash MCU with EEPROM
fH/�
fH/4
High Speed Oscillator
HIRC
fH/8
fH
Prescaler
fSYS
fH/1�
fH/3�
fH/�4
Low Speed Oscillator
fLIRC
LIRC
HLCLK
CKS�~CKS0 bits
fL
WDT
fTBC
fTB
IDLEN
Time Base 0
fSYS/4
Time Base 1
TBCK
System Clock Configurations
Note: When the system clock source fSYS is switched to fL from fH, the high speed oscillation will
stop to conserve the power. Thus there is no fH~fH/64 for peripheral circuit to use.
System Operation Modes
There are six different modes of operation for the microcontroller, each one with its own
special characteristics and which can be chosen according to the specific performance and
power requirements of the application. There are two modes allowing normal operation of the
microcontroller, the NORMAL Mode and SLOW Mode. The remaining four modes, the SLEEP0,
SLEEP1, IDLE0 and IDLE1 modes are used when the microcontroller CPU is switched off to
conserve power.
Operating Mode
Rev. 1.00
Description
CPU
fSYS
fLIRC
fTBC
NORMAL mode
On
fH~fH/64
On
On
SLOW mode
On
fL
On
On
IDLE0 mode
Off
Off
On
On
On
IDLE1 mode
Off
On
On
SLEEP0 mode
Off
Off
Off
Off
SLEEP1 mode
Off
Off
On
Off
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Cost-Effective 8-Bit Flash MCU with EEPROM
NORMAL Mode
As the name suggests this is one of the main operating modes where the microcontroller has all
of its functions operational and where the system clock is provided the high speed oscillator. This
mode operates allowing the microcontroller to operate normally with a clock source will come from
the high speed oscillator HIRC. The high speed oscillator will however first be divided by a ratio
ranging from 1 to 64, the actual ratio being selected by the CKS2~CKS0 and HLCLK bits in the
SMOD register. Although a high speed oscillator is used, running the microcontroller at a divided
clock ratio reduces the operating current.
SLOW Mode
This is also a mode where the microcontroller operates normally although now with a slower
speed clock source. The clock source used will be from the low speed oscillator LIRC. Running
the microcontroller in this mode allows it to run with much lower operating currents. In the SLOW
Mode, the fH is off.
SLEEP0 Mode
The SLEEP Mode is entered when an HALT instruction is executed and when the IDLEN bit in the
SMOD register is low. In the SLEEP0 mode the CPU will be stopped, and the fLIRC clock will be
stopped too, and the Watchdog Timer function is disabled.
SLEEP1 Mode
The SLEEP Mode is entered when an HALT instruction is executed and when the IDLEN bit in the
SMOD register is low. In the SLEEP1 mode the CPU will be stopped. However the fLIRC clocks will
continue to operate if the Watchdog Timer function is enabled.
IDLE0 Mode
The IDLE0 Mode is entered when a HALT instruction is executed and when the IDLEN bit in the
SMOD register is high and the FSYSON bit in the SMOD1 register is low. In the IDLE0 Mode the
system oscillator will be inhibited from driving the CPU but some peripheral functions will remain
operational such as the Watchdog Timer and TMs. In the IDLE0 Mode, the system oscillator will be
stopped.
IDLE1 Mode
The IDLE1 Mode is entered when a HALT instruction is executed and when the IDLEN bit in the
SMOD register is high and the FSYSON bit in the SMOD1 register is high. In the IDLE1 Mode the
system oscillator will be inhibited from driving the CPU but may continue to provide a clock source
to keep some peripheral functions operational such as the Watchdog Timer and TMs. In the IDLE1
Mode, the system oscillator will continue to run, and this system oscillator may be high speed or low
speed system oscillator. In the IDLE1 Mode, the Watchdog Timer clock, fLIRC, will be on.
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Cost-Effective 8-Bit Flash MCU with EEPROM
Control Register
A single register, SMOD and SMOD1, is used for overall control of the internal clocks within the device.
SMOD Register
Bit
7
6
5
4
3
2
1
0
Name
CKS2
CKS1
CKS0
—
LTO
HTO
IDLEN
HLCLK
R/W
R/W
R/W
R/W
—
R
R
R/W
R/W
POR
0
0
0
—
0
0
1
1
Bit 7~5CKS2~CKS0: The system clock selection when HLCLK is “0”
000: fL (fLIRC)
001: fL (fLIRC)
010: fH/64
011: fH/32
100: fH/16
101: fH/8
110: fH/4
111: fH/2
These three bits are used to select which clock is used as the system clock source. In
addition to the system clock source, which can be the LIRC, a divided version of the
high speed system oscillator can also be chosen as the system clock source.
Bit 4
Unimplemented, read as “0”
Bit 3LTO: Low speed system oscillator ready flag
0: Not ready
1: Ready
This is the low speed system oscillator ready flag which indicates when the low speed
system oscillator is stable after power on reset or a wake-up has occurred. The flag
will be low when in the SLEEP0 mode, but after a wake-up has occurred the flag will
change to a high level after 1~2 cycles if the LIRC oscillator is used.
Bit 2HTO: High speed system oscillator ready flag
0: Not ready
1: Ready
This is the high speed system oscillator ready flag which indicates when the high speed
system oscillator is stable. This flag is cleared to “0” by hardware when the device is
powered on and then changes to a high level after the high speed system oscillator is
stable. Therefore this flag will always be read as “1” by the application program after
device power-on.
Bit 1IDLEN: IDLE Mode Control
0: Disable
1: Enable
This is the IDLE Mode Control bit and determines what happens when the HALT
instruction is executed. If this bit is high, when a HALT instruction is executed the
device will enter the IDLE Mode. In the IDLE1 Mode the CPU will stop running
but the system clock will continue to keep the peripheral functions operational, if
FSYSON bit is high. If FSYSON bit is low, the CPU and the system clock will all stop
in IDLE0 mode. If the bit is low the device will enter the SLEEP Mode when a HALT
instruction is executed.
Bit 0HLCLK: System Clock Selection
0: fH/2~fH/64 or fL
1: fH
This bit is used to select if the fH clock or the fH/2~fH/64 or fL clock is used as the
system clock. When the bit is high the f H clock will be selected and if low the
fH/2~fH/64 or fL clock will be selected. When system clock switches from the fH clock
to the fL clock and the fH clock will be automatically switched off to conserve power.
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HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
SMOD1 Register
Bit
7
6
5
4
3
2
1
0
Name
FSYSON
—
—
—
RSTF
LVRF
LRF
WRF
R/W
R/W
—
—
—
R/W
R/W
R/W
R/W
POR
0
—
—
—
0
x
0
0
“x” unknown
Bit 7FSYSON: fSYS Control in IDLE Mode
0: Disable
1: Enable
Bit 6~4
Unimplemented, read as “0”
Bit 3RSTF: Reset caused by RSTC setting
0: Not occurr
1: Occurred
This bit can be clear to “0”, but cannot set to “1”. If this bit is set, only cleared by
Software or POR reset.
Bit 2LVRF: LVR function reset flag
0: Not occurr
1: Occurred
This bit is set to 1 when a specific Low Voltage Reset situation occurs. This bit can
only be cleared to 0 by the application program.
Bit 1LRF: LVR Control register software reset flag
0: Not occurr
1: Occurred
This bit is set to 1 if the LVRC register contains any non defined LVR voltage register
values. This in effect acts like a software-reset function. This bit can only be cleared to
0 by the application program.
Bit 0WRF: WDT Control register software reset flag
0: Not occur
1: Occurred
This bit is set to 1 by the WDT Control register software reset and cleared by the
application program. Note that this bit can only be cleared to 0 by the application.
program.
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HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
Operating Mode Switching
The device can switch between operating modes dynamically allowing the user to select the best
performance/power ratio for the present task in hand. In this way microcontroller operations that
do not require high performance can be executed using slower clocks thus requiring less operating
current and prolonging battery life in portable applications.
In simple terms, Mode Switching between the NORMAL Mode and SLOW Mode is executed
using the HLCLK bit and CKS2~CKS0 bits in the SMOD register while Mode Switching from the
NORMAL/SLOW Modes to the SLEEP/IDLE Modes is executed via the HALT instruction. When
a HALT instruction is executed, whether the device enters the IDLE Mode or the SLEEP Mode is
determined by the condition of the IDLEN bit in the SMOD register and FSYSON in the SMOD1
register.
When the HLCLK bit switches to a low level, which implies that clock source is switched from the
high speed clock source, fH, to the clock source, fH/2~fH/64 or fL. If the clock is from the fL, the high
speed clock source will stop running to conserve power. When this happens it must be noted that the
fH/16 and fH/64 internal clock sources will also stop running, which may affect the operation of other
internal functions such as the TMs.

 
   

 Rev. 1.00
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HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
NORMAL Mode to SLOW Mode Switching
When running in the NORMAL Mode, which uses the high speed system oscillator, and therefore
consumes more power, the system clock can switch to run in the SLOW Mode by setting the
HLCLK bit to “0” and setting the CKS2~CKS0 bits to “000” or “001” in the SMOD register.This
will then use the low speed system oscillator which will consume less power. Users may decide to
do this for certain operations which do not require high performance and can subsequently reduce
power consumption.
The SLOW Mode is sourced from the LIRC oscillator and therefore requires this oscillator to be
stable before full mode switching occurs. This is monitored using the LTO bit in the SMOD register.
         
          ­           ­          Rev. 1.00
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HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
SLOW Mode to NORMAL Mode Switching
In SLOW Mode the system uses LIRC low speed system oscillator. To switch back to the NORMAL
Mode, where the high speed system oscillator is used, the HLCLK bit should be set to “1” or
HLCLK bit is “0”, but CKS2~CKS0 is set to “010”, “011”, “100”, “101”, “110” or “111”. As a
certain amount of time will be required for the high frequency clock to stabilise, the status of the
HTO bit is checked.

          
          ­           ­           Entering the SLEEP0 Mode
There is only one way for the device to enter the SLEEP0 Mode and that is to execute the “HALT”
instruction in the application program with the IDLEN bit in SMOD register equal to “0” and the
WDT off. When this instruction is executed under the conditions described above, the following will
occur:
• The system clock, WDT clock and Time Base clock will be stopped and the application program
will stop at the “HALT” instruction.
• The Data Memory contents and registers will maintain their present condition.
• The WDT will be cleared and stopped.
• The I/O ports will maintain their present conditions.
• In the status register, the Power Down flag, PDF, will be set and the Watchdog time-out flag, TO,
will be cleared.
Rev. 1.00
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HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
Entering the SLEEP1 Mode
There is only one way for the device to enter the SLEEP1 Mode and that is to execute the “HALT”
instruction in the application program with the IDLEN bit in SMOD register equal to “0” and the
WDT on. When this instruction is executed under the conditions described above, the following will
occur:
• The system clock and Time Base clock will be stopped and the application program will stop at
the “HALT” instruction, but the WDT will remain with the clock source coming from the fLIRC
clock.
• The Data Memory contents and registers will maintain their present condition.
• The WDT will be cleared and resume counting if the WDT is enabled.
• The I/O ports will maintain their present conditions.
• In the status register, the Power Down flag, PDF, will be set and the Watchdog time-out flag, TO,
will be cleared.
Entering the IDLE0 Mode
There is only one way for the device to enter the IDLE0 Mode and that is to execute the “HALT”
instruction in the application program with the IDLEN bit in SMOD register equal to “1” and the
FSYSON bit in SMOD1 register equal to “0”. When this instruction is executed under the conditions
described above, the following will occur:
• The system clock will be stopped and the application program will stop at the “HALT”
instruction, but the Time Base clock will be on.
• The Data Memory contents and registers will maintain their present condition.
• The WDT will be cleared and resume counting if the WDT is enabled.
• The I/O ports will maintain their present conditions.
• In the status register, the Power Down flag, PDF, will be set and the Watchdog time-out flag, TO,
will be cleared.
Entering the IDLE1 Mode
There is only one way for the device to enter the IDLE1 Mode and that is to execute the “HALT”
instruction in the application program with the IDLEN bit in SMOD register equal to “1” and the
FSYSON bit in SMOD1 register equal to “1”. When this instruction is executed under the conditions
described above, the following will occur:
• The system clock and Time Base clock will be on and the application program will stop at the
“HALT” instruction.
• The Data Memory contents and registers will maintain their present condition.
• The WDT will be cleared and resume counting if the WDT is enabled.
• The I/O ports will maintain their present conditions.
• In the status register, the Power Down flag, PDF, will be set and the Watchdog time-out flag, TO,
will be cleared.
Rev. 1.00
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HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
Standby Current Considerations
As the main reason for entering the SLEEP or IDLE Mode is to keep the current consumption of the
device to as low a value as possible, perhaps only in the order of several micro-amps except in the
IDLE1 Mode, there are other considerations which must also be taken into account by the circuit
designer if the power consumption is to be minimised. Special attention must be made to the I/O pins
on the device. All high-impedance input pins must be connected to either a fixed high or low level as
any floating input pins could create internal oscillations and result in increased current consumption.
This also applies to the device which has different package types, as there may be unbonbed pins.
These must either be setup as outputs or if setup as inputs must have pull-high resistors connected.
Care must also be taken with the loads, which are connected to I/O pins, which are setup as
outputs. These should be placed in a condition in which minimum current is drawn or connected
only to external circuits that do not draw current, such as other CMOS inputs. In the IDLE1 Mode
the system oscillator is on, if the system oscillator is from the high speed system oscillator, the
additional standby current will also be perhaps in the order of several hundred micro-amps.
Wake-up
After the system enters the SLEEP or IDLE Mode, it can be woken up from one of various sources
listed as follows:
• An external reset
• An external falling edge on Port A
• A system interrupt
• A WDT overflow
If the system is woken up by an external reset, the device will experience a full system reset,
however, If The devices are woken up by a WDT overflow, a Watchdog Timer reset will be initiated.
Although both of these wake-up methods will initiate a reset operation, the actual source of the
wake-up can be determined by examining the TO and PDF flags. The PDF flag is cleared by a
system power-up or executing the clear Watchdog Timer instructions and is set when executing the
“HALT” instruction. The TO flag is set if a WDT time-out occurs, and causes a wake-up that only
resets the Program Counter and Stack Pointer, the other flags remain in their original status.
Each pin on Port A can be setup using the PAWU register to permit a negative transition on the pin
to wake-up the system. When a Port A pin wake-up occurs, the program will resume execution at
the instruction following the “HALT” instruction. If the system is woken up by an interrupt, then
two possible situations may occur. The first is where the related interrupt is disabled or the interrupt
is enabled but the stack is full, in which case the program will resume execution at the instruction
following the “HALT” instruction. In this situation, the interrupt which woke-up the device will not
be immediately serviced, but will rather be serviced later when the related interrupt is finally enabled
or when a stack level becomes free. The other situation is where the related interrupt is enabled and
the stack is not full, in which case the regular interrupt response takes place. If an interrupt request
flag is set high before entering the SLEEP or IDLE Mode, the wake-up function of the related
interrupt will be disabled.
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HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
Watchdog Timer
The Watchdog Timer is provided to prevent program malfunctions or sequences from jumping to
unknown locations, due to certain uncontrollable external events such as electrical noise.
Watchdog Timer Clock Source
The Watchdog Timer clock source is provided by the internal fLIRC clock which is supplied by the
LIRC oscillator. The Watchdog Timer source clock is then subdivided by a ratio of 28 to 215 to give
longer timeouts, the actual value being chosen using the WS2~WS0 bits in the WDTC register. The
LIRC internal oscillator has an approximate period of 32kHz at a supply voltage of 5V. However, it
should be noted that this specified internal clock period can vary with VDD, temperature and process
variations. The WDT can be enabled/disabled using the WDTC register.
Watchdog Timer Control Register
A single register, WDTC, controls the required timeout period as well as the enable/disable
operation. The WRF software reset flag will be indicated in the SMOD1 register. These registers
control the overall operation of the Watchdog Timer.
WDTC Register
Bit
7
6
5
4
3
2
1
0
Name
WE4
WE3
WE2
WE1
WE0
WS2
WS1
WS0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
1
0
1
0
0
1
1
Bit 7~3WE4~WE0: WDT function software control
10101: WDT disable
01010: WDT enable
Other values: Reset MCU
When these bits are changed to any other values by the environmental noise to reset
the microcontroller, the reset operation will be activated after 2~3 LIRC clock cycles
and the WRF bit will be set to 1 to indicate the reset source.
Bit 2~0WS2~WS0: WDT Time-out period selection
000: 28/ fLIRC
001: 29/fLIRC
010: 210/fLIRC
011: 211/fLIRC(default)
100: 212/fLIRC
101: 213/fLIRC
110: 214/fLIRC
111: 215/fLIRC
These three bits determine the division ratio of the Watchdog Timer sourece clock,
which in turn determines the timeout period.
Rev. 1.00
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HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
SMOD1 Register
Bit
7
6
5
4
3
2
1
0
Name
FSYSON
—
—
—
RSTF
LVRF
LRF
WRF
R/W
R/W
—
—
—
R/W
R/W
R/W
R/W
POR
0
—
—
—
0
x
0
0
“x” unknown
Bit 7 FSYSON: fSYS Control in IDLE Mode
Described elsewhere
Bit 6~4
Unimplemented, read as “0”
Bit 3RSTF: Reset caused by RSTC setting
Described elsewhere
Bit 2LVRF: LVR function reset flag
Described elsewhere
Bit 1LRF: LVR Control register software reset flag
Described elsewhere
Bit 0WRF: WDT Control register software reset flag
0: Not occur
1: Occurred
This bit is set to 1 by the WDT Control register software reset and cleared by the
application program. Note that this bit can only be cleared to 0 by the application
program.
Watchdog Timer Operation
The Watchdog Timer operates by providing a device reset when its timer overflows. This means
that in the application program and during normal operation the user has to strategically clear the
Watchdog Timer before it overflows to prevent the Watchdog Timer from executing a reset. This is
done using the clear watchdog instructions. If the program malfunctions for whatever reason, jumps
to an unknown location, or enters an endless loop, the clear WDT instructions will not be executed
in the correct manner, in which case the Watchdog Timer will overflow and reset the device. With
regard to the Watchdog Timer enable/disable function, there are five bits, WE4~WE0, in the WDTC
register to additional enable/disable and reset control of the Watchdog Timer.
WE4~WE0 Bits
WDT Function
10101B
Disable
01010B
Enable
Any other value
Reset MCU
Watchdog Timer Enable/Disable Control
Under normal program operation, a Watchdog Timer time-out will initialise a device reset and set
the status bit TO. However, if the system is in the SLEEP or IDLE Mode, when a Watchdog Timer
time-out occurs, the TO bit in the status register will be set and only the Program Counter and Stack
Pointer will be reset. Four methods can be adopted to clear the contents of the Watchdog Timer.
The first is a WDT reset, which means a value other than 01010B and 10101B is written into the
WE4~WE0 bit locations, the second is an external hardware reset, which means a low level on the
external reset pin, the third is using the Watchdog Timer software clear instructions and the fourth
is via a HALT instruction. There is only one method of using software instruction to clear the
Watchdog Timer. That is to use the single “CLR WDT” instruction to clear the WDT.
The maximum time-out period is when the 215 division ratio is selected. As an example, with a
32kHz LIRC oscillator as its source clock, this will give a maximum watchdog period of around 1
second for the 215 division ratio, and a minimum timeout of 7.8ms for the 28 division ration.
Rev. 1.00
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HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
WDTC Register
WE4~WE0 bits
Reset MCU
CLR
RES pin reset
“CLR WDT”Instruction
“HALT”Instruction
LIRC
fLIRC
11-stage Divider
8-to-1 MUX
7-stage Divider
WDT Time-out
(28/fLIRC ~ 215/fLIRC)
WS2~WS0
(fLIRC/21 ~ fLIRC/211)
Watchdog Timer
Reset and Initialisation
A reset function is a fundamental part of any microcontroller ensuring that the device can be set
to some predetermined condition irrespective of outside parameters. The most important reset
condition is after power is first applied to the microcontroller. In this case, internal circuitry will
ensure that the microcontroller, after a short delay, will be in a well defined state and ready to
execute the first program instruction. After this power-on reset, certain important internal registers
will be set to defined states before the program commences. One of these registers is the Program
Counter, which will be reset to zero forcing the microcontroller to begin program execution from the
lowest Program Memory address.
In addition to the power-on reset, situations may arise where it is necessary to forcefully apply
a reset condition when the microcontroller is running. One example of this is where after power
has been applied and the microcontroller is already running, the RES line is forcefully pulled low.
In such a case, known as a normal operation reset, some of the microcontroller registers remain
unchanged allowing the microcontroller to proceed with normal operation after the reset line is
allowed to return high.
Another type of reset is when the Watchdog Timer overflows and resets the microcontroller. All
types of reset operations result in different register conditions being setup. Another reset exists in the
form of a Low Voltage Reset, LVR, where a full reset is implemented in situations where the power
supply voltage falls below a certain threshold.
Reset Functions
There are five ways in which a microcontroller reset can occur, through events occurring both
internally and externally.
Power-on Reset
The most fundamental and unavoidable reset is the one that occurs after power is first applied to
the microcontroller. As well as ensuring that the Program Memory begins execution from the first
memory address, a power-on reset also ensures that certain other registers are preset to known
conditions. All the I/O port and port control registers will power up in a high condition ensuring that
all pins will be first set to inputs.
Rev. 1.00
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HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
Note: tRSTD is power-on delay, typical time=50ms
Power-On Reset Timing Chart
RES Pin Reset
Although the microcontroller has an internal RC reset function, if the VDD power supply rise time
is not fast enough or does not stabilise quickly at power-on, the internal reset function may be
incapable of providing proper reset operation. For this reason it is recommended that an external
RC network is connected to the RES pin, whose additional time delay will ensure that the RES pin
remains low for an extended period to allow the power supply to stabilise. During this time delay,
normal operation of the microcontroller will be inhibited. After the RES line reaches a certain
voltage value, the reset delay time tRSTD is invoked to provide an extra delay time after which the
microcontroller will begin normal operation. The abbreviation SST in the figures stands for System
Start-up Timer.
For most applications a resistor connected between VDD and the RES pin and a capacitor connected
between VSS and the RES pin will provide a suitable external reset circuit. Any wiring connected
to the RES pin should be kept as short as possible to minimize any stray noise interference. For
applications that operate within an environment where more noise is present the Enhanced Reset
Circuit shown is recommended.
VDD
0.01µF**
VDD
10kΩ~
100kΩ
1N4148*
0.1µF~1µF
300Ω*
PA7/RES
VSS
Note: “*” It is recommended that this component is added for added ESD protection
“**” It is recommended that this component is added in environments where power line noise
is significant
External RES Circuit
More information regarding external reset circuits is located in Application Note HA0075E on the
Holtek website.
Pulling the RES Pin low using external hardware will also execute a device reset. In this case, as in
the case of other resets, the Program Counter will reset to zero and program execution initiated from
this point.
Note: tRSTD is power-on delay, typical time=16.7ms
RES Reset Timing Chart
Rev. 1.00
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HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
• RSTC Register
Bit
7
6
5
4
3
2
1
0
Name
RSTC7
RSTC6
RSTC5
RSTC4
RSTC3
RSTC2
RSTC1
RSTC0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
1
0
1
0
1
0
1
Bit 7~0RSTC7~RSTC0: PA7/RES select
01010101B: PA7 pin or other functions
10101010B: RES pin
Other Values: MCU reset (reset will be active after 2~3 LIRC clock for debounce time)
All reset will reset this register as POR value except WDT time out Hardware warm
reset.
• SMOD1 Register
Bit
7
6
5
4
3
2
1
0
Name
FSYSON
—
—
—
RSTF
LVRF
LRF
WRF
R/W
R/W
—
—
—
R/W
R/W
R/W
R/W
POR
0
—
—
—
0
x
0
0
“x” unknown
Bit 7 FSYSON: fSYS Control in IDLE Mode
Described elsewhere
Bit 6~4
Unimplemented, read as “0”
Bit 3RSTF: Reset caused by RSTC setting
0: Not occur
1: Occurred
This bit can be clear to “0”, but cannot set to “1”. If this bit is set, only cleared by
Software or POR reset.
Bit 2LVRF: LVR function reset flag
Described elsewhere
Bit 1LRF: LVR Control register software reset flag
Described elsewhere
Bit 0WRF: WDT Control register software reset flag
Described elsewhere
Low Voltage Reset – LVR
The microcontroller contains a low voltage reset circuit in order to monitor the supply voltage of
the device and provide an MCU reset should the value fall below a certain predefined level. The
LVR function is enabled or disabled by configuring the LVRC register during the normal and slow
modes with a specific LVR voltage VLVR. If the supply voltage of the device drops to within a range
of 0.9V~VLVR such as might occur when changing the battery, the LVR will automatically reset the
device internally and the LVRF bit in the SMOD1 register will also be set to1. For a valid LVR
signal, a low voltage, i.e., a voltage in the range between 0.9V~VLVR must exist for greater than the
value tLVR specified in the A.C. characteristics. If the low voltage state does not exceed this value,
the LVR will ignore the low supply voltage and will not perform a reset function. The actual VLVR is
1.7V, the LVR will reset the device after 2~3 LIRC clock cycles. Note that the LVR function will be
automatically disabled when the device enters the SLEEP/IDLE mode.
Note:tRSTD is power-on delay, typical time=50ms
Low Voltage Reset Timing Chart
Rev. 1.00
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HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
• LVRC Register
Bit
7
6
5
4
3
2
1
0
Name
LVS7
LVS6
LVS5
LVS4
LVS3
LVS2
LVS1
LVS0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
1
0
1
1
0
1
0
Bit 7~0LVS7~LVS0: LVR voltage select
01011010B: 1.7V (default)
10100101B: LVR disable
Other Values: MCU reset (reset will be active after 2~3 LIRC clock for debounce time)
When an actual low voltage condition occurs, as specified by the defined LVR voltage
value, an MCU reset will be generated. In this situation the register contents will
remain the same after such a reset occurs.
Any register value, other than the defined LVR value, will also result in the generation
of an MCU reset. The reset operation will be activated after 2~3 LIRC clock cycles.
However in this situation the register contents will be reset to the POR value.
• SMOD1 Register
Bit
7
6
5
4
3
2
1
0
Name
FSYSON
—
—
—
RSTF
R/W
R/W
—
—
—
R/W
LVRF
LRF
WRF
R/W
R/W
POR
0
—
—
—
0
R/W
x
0
0
“x” unknown
Bit 7FSYSON: fSYS Control in IDLE Mode
Described elsewhere
Bit 6~4
Unimplemented, read as “0”
Bit 3RSTF: Reset caused by RSTC setting
Described elsewhere
Bit 2LVRF: LVR function reset flag
0: Not occurr
1: Occurred
This bit is set to 1 when a specific Low Voltage Reset situation occurs. This bit can
only be cleared to 0 by the application program.
Bit 1LRF: LVR Control register software reset flag
0: Not occurr
1: Occurred
This bit is set to 1 if the LVRC register contains any non defined LVR voltage register
values. This in effect acts like a software-reset function. This bit can only be cleared to
0 by the application program.
Bit 0WRF: WDT Control register software reset flag
Described elsewhere
Watchdog Time-out Reset during Normal Operation
The Watchdog time-out Reset during normal operation is the same as an LVR reset except that the
Watchdog time-out flag TO will be set to “1”.
Note: tRSTD is power-on delay, typical time=16.7ms
WDT Time-out Reset during Normal Operation Timing Chart
Rev. 1.00
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Cost-Effective 8-Bit Flash MCU with EEPROM
Watchdog Time-out Reset during SLEEP or IDLE Mode
The Watchdog time-out Reset during SLEEP or IDLE Mode is a little different from other kinds
of reset. Most of the conditions remain unchanged except that the Program Counter and the Stack
Pointer will be cleared to “0” and the TO flag will be set to “1”. Refer to the A.C. Characteristics for
tSST details.
WDT Time-out Reset during SLEEP or IDLE Timing Chart
Reset Initial Conditions
The different types of reset described affect the reset flags in different ways. These flags, known
as PDF and TO are located in the status register and are controlled by various microcontroller
operations, such as the SLEEP or IDLE Mode function or Watchdog Timer. The reset flags are
shown in the table.
TO
PDF
0
0
Power-on reset
RESET Conditions
u
u
RES, LVR reset during NORMAL or SLOW Mode operation
1
u
WDT time-out reset during NORMAL or SLOW Mode operation
1
1
WDT time-out reset during IDLE or SLEEP Mode operation
Note: “u” stands for unchanged
The following table indicates the way in which the various components of the microcontroller are
affected after a power-on reset occurs.
Item
Condition After RESET
Program Counter
Reset to zero
Interrupts
All interrupts will be disabled
WDT
Clear after reset, WDT begins counting
Timer Modules
Timer Modules will be turned off
Input/Output Ports
I/O ports will be setup as inputs
Stack Pointer
Stack Pointer will point to the top of the stack
The different kinds of resets all affect the internal registers of the microcontroller in different ways.
To ensure reliable continuation of normal program execution after a reset occurs, it is important to
know what condition the microcontroller is in after a particular reset occurs. The following table
describes how each type of reset affects each of the microcontroller internal registers. Note that
where more than one package type exists the table will reflect the situation for the larger package
type.
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Cost-Effective 8-Bit Flash MCU with EEPROM
HT66F302
HT66F303
MP0
●
●
1xxx xxxx 1xxx xxxx 1xxx xxxx
1xxx xxxx
MP1
●
●
1xxx xxxx 1xxx xxxx 1xxx xxxx
1xxx xxxx
1uuu uuuu
BP
●
●
---- ---0 ---- ---0 ---- ---0
---- ---0
---- ---u
Register
Reset
(Power On)
RES Reset
LVR Reset
WDT Time-out
WDT Time-out
(Normal Operation)
(HALT)*
1uuu uuuu
ACC
●
●
x x x x x x x x uuuu uuuu uuuu uuuu
uuuu uuuu
uuuu uuuu
PCL
●
●
0000 0000 0000 0000 0000 0000
0000 0000
0000 0000
TBLP
●
●
x x x x x x x x uuuu uuuu uuuu uuuu
uuuu uuuu
uuuu uuuu
TBLH
●
●
--xx xxxx --uu uuuu --uu uuuu
--uu uuuu
--uu uuuu
STATUS
●
●
--00 xxxx --uu uuuu --uu uuuu
--1u uuuu
- - 11 u u u u
SMOD
●
●
0 0 0 - 0 0 11 0 0 0 - 0 0 11 0 0 0 - 0 0 11
0 0 0 - 0 0 11
uuu- uuuu
LVPUC
●
●
---- 0--- ---- 0--- ---- 0---
---- 0---
---- u---
INTEG
●
●
---- --00 ---- --00 ---- --00
---- --00
---- --uu
INTC0
●
●
-000 0000 -000 0000 -000 0000
-000 0000
-uuu uuuu
INTC1
●
●
0000 0000 0000 0000 0000 0000
0000 0000
uuuu uuuu
MFI0
●
●
--00 --00 --00 --00 --00 --00
--00 --00
--uu --uu
MFI1
●
●
--00 --00 --00 --00 --00 --00
--00 --00
--uu --uu
PA
●
●
1111 1111 1111 1111 1111 1111
1111 1111
uuuu uuuu
PAC
●
●
1111 1111 1111 1111 1111 1111
1111 1111
uuuu uuuu
PAPU
●
●
0000 0000 0000 0000 0000 0000
0000 0000
uuuu uuuu
PAWU
●
●
0000 0000 0000 0000 0000 0000
0000 0000
uuuu uuuu
IFS0
●
●
0000 0-00 0000 0-00 0000 0-00
0000 0-00
uuuu u-uu
WDTC
●
●
0 1 0 1 0 0 11 0 1 0 1 0 0 11 0 1 0 1 0 0 11
0 1 0 1 0 0 11
uuuu uuuu
TBC
●
●
0 0 11 - 111 0 0 11 - 111 0 0 11 - 111
0 0 11 - 111
uuuu –uuu
SMOD1
●
●
0--- 0x00 0--- 0x00 0--- 0100
0--- 0x00
u--- uuuu
LVRC
●
●
0101 1010 0101 1010 0101 1010
0101 1010
uuuu uuuu
EEA
●
●
---0 0000 ---0 0000 ---0 0000
---0 0000
---u uuuu
EED
●
●
0000 0000 0000 0000 0000 0000
0000 0000
uuuu uuuu
SADOL(ADRFS=0)
●
●
xxxx ---- xxxx ---- xxxx ----
xxxx ----
uuuu ----
SADOL(ADRFS=1)
●
●
xxxx xxxx xxxx xxxx xxxx xxxx
xxxx xxxx
uuuu uuuu
SADOH(ADRFS=0)
●
●
xxxx xxxx xxxx xxxx xxxx xxxx
xxxx xxxx
uuuu uuuu
SADOH(ADRFS=1)
●
●
---- xxxx ---- xxxx ---- xxxx
---- xxxx
---- uuuu
SADC0
●
●
0000 --00 0000 --00 0000 --00
0000 --00
uuuu --uu
SADC1
●
●
000- -000 000- -000 000- -000
000- -000
uuu- -uuu
SADC2
●
●
0000 0000 0000 0000 0000 0000
0000 0000
uuuu uuuu
RSTC
●
●
0101 0101 0101 0101 0101 0101
0101 0101
uuuu uuuu
PASR
●
●
0000 0000 0000 0000 0000 0000
0000 0000
uuuu uuuu
PBSR
–
●
--00 0000 --00 0000 --00 0000
--00 0000
--uu uuuu
STMC0
●
●
0000 0000 0000 0000 0000 0000
0000 0000
uuuu uuuu
STMC1
●
●
0000 0000 0000 0000 0000 0000
0000 0000
uuuu uuuu
STMDL
●
●
0000 0000 0000 0000 0000 0000
0000 0000
uuuu uuuu
STMDH
●
●
---- --00 ---- --00 ---- --00
---- --00
---- --uu
STMAL
●
●
0000 0000 0000 0000 0000 0000
0000 0000
uuuu uuuu
STMAH
●
●
---- --00 ---- --00 ---- --00
---- --00
---- --uu
PB
–
●
- - 11 1111 - - 11 1111 - - 11 1111
- - 11 1111
--uu uuuu
PBC
–
●
- - 11 1111 - - 11 1111 - - 11 1111
- - 11 1111
--uu uuuu
PBPU
–
●
--00 0000 --00 0000 --00 0000
--00 0000
--uu uuuu
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HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
HT66F302
HT66F303
PTMC0
●
●
0000 0--- 0000 0--- 0000 0---
0000 0---
uuuu u---
PTMC1
●
●
0000 0000 0000 0000 0000 0000
0000 0000
uuuu uuuu
PTMDL
●
●
0000 0000 0000 0000 0000 0000
0000 0000
uuuu uuuu
PTMDH
●
●
---- --00 ---- --00 ---- --00
---- --00
---- --uu
PTMAL
●
●
0000 0000 0000 0000 0000 0000
0000 0000
uuuu uuuu
PTMAH
●
●
---- --00 ---- --00 ---- --00
---- --00
---- --uu
PTMRPL
●
●
0000 0000 0000 0000 0000 0000
0000 0000
uuuu uuuu
Register
Reset
(Power On)
RES Reset
WDT Time-out
WDT Time-out
(Normal Operation)
(HALT)*
LVR Reset
PTMRPH
●
●
---- --00 ---- --00 ---- --00
---- --00
---- --uu
EEC
●
●
---- 0000 ---- 0000 ---- 0000
---- 0000
---- uuuu
Note: “*” stands for warm reset
“-” not implement
“u” stands for “unchanged”
“x” stands for “unknown”
Input/Output Ports
Holtek microcontrollers offer considerable flexibility on their I/O ports. With the input or output
designation of every pin fully under user program control, pull-high selections for all ports and
wake-up selections on certain pins, the user is provided with an I/O structure to meet the needs of a
wide range of application possibilities.
The devices provide bidirectional input/output lines labeled with port names PA~PB. These I/O
ports are mapped to the RAM Data Memory with specific addresses as shown in the Special Purpose
Data Memory table. All of these I/O ports can be used for input and output operations. For input
operation, these ports are non-latching, which means the inputs must be ready at the T2 rising edge
of instruction “MOV A, [m]”, where m denotes the port address. For output operation, all the data is
latched and remains unchanged until the output latch is rewritten.
Register
Name
Bit
7
6
5
4
3
2
1
0
PA
PA7
PA6
PA5
PA4
PA3
PA2
PA1
PA0
PAC
PAC7
PAC6
PAC5
PAC4
PAC3
PAC2
PAC1
PAC0
PAPU
PAPU7
PAPU6
PAPU5
PAPU4
PAPU3
PAPU2
PAPU1
PAPU0
PAWU
PAWU7
PAWU6
PAWU5
PAWU4
PAWU3
PAWU2
PAWU1
PAWU0
I/O Control Register List – HT66F302
Bit
Register
Name
7
6
5
4
3
2
1
0
PA
PA7
PA6
PA5
PA4
PA3
PA2
PA1
PA0
PAC
PAC7
PAC6
PAC5
PAC4
PAC3
PAC2
PAC1
PAC0
PAPU
PAPU7
PAPU6
PAPU5
PAPU4
PAPU3
PAPU2
PAPU1
PAPU0
PAWU
PAWU7
PAWU6
PAWU5
PAWU4
PAWU3
PAWU2
PAWU1
PAWU0
PB
—
—
PB5
PB4
PB3
PB2
PB1
PB0
PBC
—
—
PBC5
PBC4
PBC3
PBC2
PBC1
PBC0
PBPU
—
—
PBPU5
PBPU4
PBPU3
PBPU2
PBPU1
PBPU0
I/O Control Register List – HT66F303
Rev. 1.00
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HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
Pull-high Resistors
Many product applications require pull-high resistors for their switch inputs usually requiring the
use of an external resistor. To eliminate the need for these external resistors, all I/O pins, when
configured as an input have the capability of being connected to an internal pull-high resistor. These
pull-high resistors are selected using register LVPUC and PAPU~PBPU, and are implemented using
weak PMOS transistors.
Note that the pull-high resistor can be controlled by the relevant pull-high control register only
when the pin-shared functional pin is selected as an input or NMOS output. Otherwise, the pull-high
resistors can not be enabled.
LVPUC Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
LVPU
—
—
—
R/W
—
—
—
—
R/W
—
—
—
POR
—
—
—
—
0
—
—
—
Bit 7~4
Unimplemented, read as “0”
Bit 3LVPU: Low Voltage Pull-High resistor Control
0: all pin pull high resistor is 30kΩ @ 5V
1: all pin pull high resistor is 7.5kΩ (10kΩ//30kΩ) @ 5V
Bit 2~0
Unimplemented, read as “0”
PAPU Register
Bit
7
6
5
4
3
2
1
0
Name
PAPU7
PAPU6
PAPU5
PAPU4
PAPU3
PAPU2
PAPU1
PAPU0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~0
I/O Port A bit 7~bit 0 Pull-High Control
0: Disable
1: Enable
PBPU Register – HT66F303
Rev. 1.00
Bit
7
6
5
4
3
2
1
0
Name
—
—
PBPU5
PBPU4
PBPU3
PBPU2
PBPU1
PBPU0
R/W
—
—
R/W
R/W
R/W
R/W
R/W
R/W
POR
—
—
0
0
0
0
0
0
Bit 7~6
Unimplemented, read as “0”
Bit 5~0
I/O Port B bit 5~bit 0 Pull-High Control
0: Disable
1: Enable
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HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
Port A Wake-up
The HALT instruction forces the microcontroller into the SLEEP or IDLE Mode which preserves
power, a feature that is important for battery and other low-power applications. Various methods
exist to wake-up the microcontroller, one of which is to change the logic condition on one of the Port
A pins from high to low. This function is especially suitable for applications that can be woken up
via external switches. Each pin on Port A can be selected individually to have this wake-up feature
using the PAWU register.
Note that the wake-up function can be controlled by the wake-up control registers only when the
pin-shared functional pin is selected as general purpose input/output and the MCU enters the SLEEP
or IDLE mode.
PAWU Register
Bit
7
6
5
4
3
2
1
0
Name
PAWU7
PAWU6
PAWU5
PAWU4
PAWU3
PAWU2
PAWU1
PAWU0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~0
I/O Port A bit 7~bit 0 Wake Up Control
0: Disable
1: Enable
I/O Port Control Registers
Each I/O port has its own control register known as PAC~PBC, to control the input/output
configuration. With these control registers, each CMOS output or input can be reconfigured
dynamically under software control. Each pin of the I/O ports is directly mapped to a bit in its
associated port control register. For the I/O pin to function as an input, the corresponding bit of the
control register must be written as a “1”. This will then allow the logic state of the input pin to be
directly read by instructions. When the corresponding bit of the control register is written as a “0”,
the I/O pin will be setup as a CMOS output. If the pin is currently setup as an output, instructions
can still be used to read the output register. However, it should be noted that the program will in fact
only read the status of the output data latch and not the actual logic status of the output pin.
PAC Register
Bit
7
6
5
4
3
2
1
0
Name
PAC7
PAC6
PAC5
PAC4
PAC3
PAC2
PAC1
PAC0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
1
1
1
1
1
1
1
1
Bit 7~0
I/O Port A bit 7~bit 0 Input/Output Control
0: Output
1: Input
PBC Register – HT66F303
Bit
Rev. 1.00
7
6
5
4
3
2
1
0
Name
—
—
PBC5
PBC4
PBC3
PBC2
PBC1
PBC0
R/W
—
—
R/W
R/W
R/W
R/W
R/W
R/W
POR
—
—
1
1
1
1
1
1
Bit 7~6
Unimplemented, read as “0”
Bit 5~0
I/O Port B bit 5~bit 0 Input/Output Control
0: Output
1: Input
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May 06, 2016
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Cost-Effective 8-Bit Flash MCU with EEPROM
Pin-shared Functions
The flexibility of the microcontroller range is greatly enhanced by the use of pins that have more
than one function. Limited numbers of pins can force serious design constraints on designers but by
supplying pins with multi-functions, many of these difficulties can be overcome. For these pins, the
desired function of the multi-function I/O pins is selected by a series of registers via the application
program control.
Pin-shared Registers
The limited number of supplied pins in a package can impose restrictions on the amount of functions
a certain device can contain. However by allowing the same pins to share several different functions
and providing a means of function selection, a wide range of different functions can be incorporated
into even relatively small package sizes. Each device includes Port “x” output function Selection
register, labeled as PxSR, and Input Function Selection register, labeled as IFS0, which can select
the desired functions of the multi-function pin-shared pins.
When the pin-shared input function is selected to be used, the corresponding input and output
functions selection should be properly managed. However, if the external interrupt function is
selected to be used, the relevant output pin-shared function should be selected as an I/O function and
the interrupt input signal should be selected.
The most important point to note is to make sure that the desired pin-shared function is properly
selected and also deselected. To select the desired pin-shared function, the pin-shared function
should first be correctly selected using the corresponding pin-shared control register. After that the
corresponding peripheral functional setting should be configured and then the peripheral function
can be enabled. To correctly deselect the pin-shared function, the peripheral function should first be
disabled and then the corresponding pin-shared function control register can be modified to select
other pin-shared functions.
Bit
Register
Name
7
6
5
4
3
2
1
0
PASR
PAS7
PAS6
PAS5
PAS4
PAS3
PAS2
PAS1
PAS0
STPIPS
PTPIPS
—
INTPS1
INTPS0
IFS0
PTCKPS1 PTCKPS0 STCKPS
Pin-shared Function Selection Registers List – HT66F302
Bit
Register
Name
7
6
5
4
3
2
1
0
PASR
PAS7
PAS6
PAS5
PAS4
PAS3
PAS2
PAS1
PAS0
PBSR
—
—
PBS5
PBS4
PBS3
PBS2
PBS1
PBS0
STPIPS
PTPIPS
—
INTPS1
INTPS0
IFS0
PTCKPS1 PTCKPS0 STCKPS
Pin-shared Function Selection Registers List – HT66F303
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HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
PASR Register
Bit
7
6
5
4
3
2
1
0
Name
PAS7
PAS6
PAS5
PAS4
PAS3
PAS2
PAS1
PAS0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7PAS7: PA7 Pin-Shared Control Bit
0: PA7/PTCK
1: STPB
Note: PAS7 is valid when RSTC=55H
Bit 6PAS6: PA6 Pin-Shared Control Bit
0: PA6/PTCK/STPI
1: STP
Bit 5PAS5: PA5 Pin-Shared Control Bit
0: PA4/INT/PTCK
1: STP
Bit 4PAS4: PA4 Pin-Shared Control Bit
0: PA3/INT/STCK
1: AN3
Bit 3PAS3: PA3 Pin-Shared Control Bit
0: PA2/INT/STCK
1: AN2
Bit 2~1PAS2~PAS1: PA2~PA1 Pin-Shared Control Bits
0X: PA1
10: VREFI
11: AN1
Bit 0PAS0: PA0 Pin-Shared Control Bit
0: PA0/STPI
1: AN0
PBSR Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
PBS5
PBS4
PBS3
PBS2
PBS1
PBS0
R/W
—
—
R/W
R/W
R/W
R/W
R/W
R/W
POR
—
—
0
0
0
0
0
0
Bit 7~6
Unimplemented, read as “0”
Bit 5PBS5: PB5 Pin-Shared Control Bit
0: PB5
1: PTP
Bit 4PBS4: PB4 Pin-Shared Control Bit
0: PB4
1: PTPB
Bit 3PBS3: PB3 Pin-Shared Control Bit
0: PB3
1: PTP
Bit 2PBS2: PB2 Pin-Shared Control Bits
0: PB2
1: PTPB
Bit 1PBS1: PB1 Pin-Shared Control Bits
0: PB1/PTCK
1: STPB
Bit 0PBS0: PB0 Pin-Shared Control Bit
0: PB0/PTP
1: VREFO
Rev. 1.00
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HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
IFS0 Register
Bit
Name
7
6
5
PTCKPS1 PTCKPS0 STCKPS
4
3
2
1
0
STPIPS
PTPIPS
—
INTPS1
INTPS0
R/W
R/W
R/W
R/W
R/W
R/W
—
R/W
R/W
POR
0
0
0
0
0
—
0
0
Bit 7~6PTCKPS1~PTCKPS0: PTCK Pin Remapping Control
00: PTCK on PA4 (default)
01: PTCK on PA6
10: PTCK on PA7
11: PTCK on PB1 (HT66F303); Undefined(HT66F302)
Bit 5STCKPS: STCK Pin Remapping Control
0: STCK on PA3 (default)
1: STCK on PA2
Bit 4STPIPS: STPI Pin Remapping Control
0: STPI on PA6 (default)
1: STPI on PA0
Bit 3PTPIPS: PTPI Pin Remapping Control
0: PTPI on PA5 (default)
1: PTPI on PB0 (HT66F303); Undefined(HT66F302)
Bit 2
Unimplemented, read as “0”
Bit 1~0INTPS1~INTPS0: INT Pin Remapping Control
00: INT on PA3 (default)
01: INT on PA2
10: INT on PA4
11: INT on PA5
I/O Pin Structures
The accompanying diagrams illustrate the internal structures of some generic I/O pin types. As
the exact logical construction of the I/O pin will differ from these drawings, they are supplied as a
guide only to assist with the functional understanding of the I/O pins. The wide range of pin-shared
structures does not permit all types to be shown.
   
   Generic Input/Output Structure
Rev. 1.00
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Cost-Effective 8-Bit Flash MCU with EEPROM
 €  
 ­
­
   
A/D Input/Output Structure
Programming Considerations
Within the user program, one of the first things to consider is port initialisation. After a reset, all
of the I/O data and port control registers will be set high. This means that all I/O pins will default
to an input state, the level of which depends on the other connected circuitry and whether pullhigh selections have been chosen. If the port control registers are then programmed to setup some
pins as outputs, these output pins will have an initial high output value unless the associated port
data registers are first programmed. Selecting which pins are inputs and which are outputs can be
achieved byte-wide by loading the correct values into the appropriate port control register or by
programming individual bits in the port control register using the “SET [m].i” and “CLR [m].i”
instructions. Note that when using these bit control instructions, a read-modify-write operation takes
place. The microcontroller must first read in the data on the entire port, modify it to the required new
bit values and then rewrite this data back to the output ports.
Port A has the additional capability of providing wake-up functions. When the device is in the
SLEEP or IDLE Mode, various methods are available to wake the device up. One of these is a high
to low transition of any of the Port A pins. Single or multiple pins on Port A can be setup to have this
function.
Rev. 1.00
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HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
Timer Modules – TM
One of the most fundamental functions in any microcontroller device is the ability to control and
measure time. To implement time related functions the devices include several Timer Modules,
abbreviated to the name TM. The TMs are multi-purpose timing units and serve to provide
operations such as Timer/Counter, Input Capture, Compare Match Output and Single Pulse Output
as well as being the functional unit for the generation of PWM signals. Each of the TMs has two
individual interrupts. The addition of input and output pins for each TM ensures that users are
provided with timing units with a wide and flexible range of features.
The common features of the different TM types are described here with more detailed information
provided in the individual Standard and Periodic TM sections.
Introduction
The devices contain two TMs. Each individual TM can be categorised as a certain type, namely
Standard Type TM or Periodic Type TM. Although similar in nature, the different TM types vary in
their feature complexity. The common features to the Standard and Periodic TMs will be described
in this section and the detailed operation will be described in corresponding sections. The main
features and differences between the two types of TMs are summarised in the accompanying table.
STM
PTM
Timer/Counter
Function
√
√
I/P Capture
√
√
Compare Match Output
√
√
PWM Channels
1
1
Single Pulse Output
PWM Alignment
PWM Adjustment Period & Duty
1
1
Edge
Edge
Duty or Period
Duty or Period
TM Function Summary
Device
HT66F302/HT66F303
STM
PTM
10-bit STM
10-bit PTM
TM Name/Type Reference
TM Operation
The two different types of TM offer a diverse range of functions, from simple timing operations
to PWM signal generation. The key to understanding how the TM operates is to see it in terms of
a free running counter whose value is then compared with the value of pre-programmed internal
comparators. When the free running counter has the same value as the pre-programmed comparator,
known as a compare match situation, a TM interrupt signal will be generated which can clear the
counter and perhaps also change the condition of the TM output pin. The internal TM counter is
driven by a user selectable clock source, which can be an internal clock or an external pin.
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TM Clock Source
The clock source which drives the main counter in each TM can originate from various sources. The
selection of the required clock source is implemented using the xTCK2~xTCK0 bits in the xTM
control registers. The clock source can be a ratio of either the system clock fSYS or the internal high
clock fH, the fTBC clock source or the external xTCK pin. The xTCK pin clock source is used to allow
an external signal to drive the TM as an external clock source or for event counting.
TM Interrupts
The Standard and Periodic type TMs each has two internal interrupts, the internal comparator A
or comparator P, which generate a TM interrupt when a compare match condition occurs. When a
TM interrupt is generated, it can be used to clear the counter and also to change the state of the TM
output pin. TM External Pins
Each of the TMs, irrespective of what type, has two TM input pins, with the label xTCK and
xTPI. The TM input pin xTCK, is essentially a clock source for the TM and is selected using the
xTCK2~xTCK0 bits in the xTMC0 register. This external TM input pin allows an external clock
source to drive the internal TM. This external TM input pin is shared with other functions but will
be connected to the internal TM if selected using the xTCK2~xTCK0 bits. The TM input pin can be
chosen to have either a rising or falling active edge.
The other TM input pin, xTPI, is the capture input whose active edge can be a rising edge, a falling
edge or both rising and falling edges and the active edge transition type is selected using the xTIO1
and xTIO0 bits in the xTMC1 register.
The TMs each have two output pins with the label xTP and xTPB. When the TM is in the Compare
Match Output Mode, these pins can be controlled by the TM to switch to a high or low level or to
toggle when a compare match situation occurs. The external xTP output pin is also the pin where the
TM generates the PWM output waveform. As the TM output pins are pin-shared with other function,
the TM output function must first be setup using registers. A single bit in one of the registers
determines if its associated pin is to be used as an external TM output pin or if it is to have another
function. The number of output pins for each TM type is different, the details are provided in the
accompanying table.
Device
HT66F302/HT66F303
STM
PTM
Input
Output
Input
Output
STCK, STPI
STP, STPB
PTCK, PTPI
PTP, PTPB
Note: For the HT66F302, the PTP and PTPB pins are not bonded to external pins.
TM Input/Output Pins
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TM Input/Output Pin Selection
Selecting to have a TM input/output or whether to retain its other shared function is implemented
using the relevant pin-shared function selection registers, with the corresponding selection bits in
each pin-shared function register corresponding to a TM input/output pin. Configuring the selection
bits correctly will setup the corresponding pin as a TM input/output. The details of the pin-shared
function selection are described in the pin-shared function section.
STM
Inverting Output
STPB
Output
STP
Capture Input
STPI
TCK Input
STCK
STM Function Pin Control Block Diagram
Inverting Output
PTM
PTPB
Output
PTP
Capture Input
PTPI
TCK Input
PTCK
PTM Function Pin Control Block Diagram
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Programming Considerations
The TM Counter Registers and the Capture/Compare CCRA register, and CCRP register pair for
Periodic Timer Module, all have a low and high byte structure. The high bytes can be directly
accessed, but as the low bytes can only be accessed via an internal 8-bit buffer, reading or writing
to these register pairs must be carried out in a specific way. The important point to note is that data
transfer to and from the 8-bit buffer and its related low byte only takes place when a write or read
operation to its corresponding high byte is executed.
As the CCRA register and CCRP registers are implemented in the way shown in the following
diagram and accessing the register is carried out CCRP low byte register using the following
access procedures. Accessing the CCRA or CCRP low byte register without following these access
procedures will result in unpredictable values.
xT� Counter Register (Read onl�)
xT�DL
xT�DH
8-bit Buffer
xT�AL
xT�AH
xT� CCRA Register (Read/Write)
xT�RPL
xT�RPH
PT� CCRP Register (Read/Write)
Data
Bus
The following steps show the read and write procedures:
• Writing Data to CCRA or PTM CCRP
♦♦
Step 1. Write data to Low Byte xTMAL or PTMRPL
––note that here data is only written to the 8-bit buffer.
♦♦
Step 2. Write data to High Byte xTMAH or PTMRPH
––here data is written directly to the high byte registers and simultaneously data is latched
from the 8-bit buffer to the Low Byte registers.
• Reading Data from the Counter Registers and CCRA or PTM CCRP
Rev. 1.00
♦♦
Step 1. Read data from the High Byte xTMDH, xTMAH or PTMRPH
––here data is read directly from the High Byte registers and simultaneously data is latched
from the Low Byte register into the 8-bit buffer.
♦♦
Step 2. Read data from the Low Byte xTMDL, xTMAL or PTMRPL
––this step reads data from the 8-bit buffer.
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Standard Type TM – STM
The Standard Type TM contains five operating modes, which are Compare Match Output, Timer/
Event Counter, Capture Input, Single Pulse Output and PWM Output modes. The Standard TM can
be controlled with two external input pins and can drive two external output pins.
Device
HT66F302/HT66F303
TM Type
TM Name
TM Input Pin
TM Output Pin
10-bit STM
STM
STCK, STPI
STP, STPB
CCRP
fSYS/4
fSYS
fH/1�
fH/�4
fTBC
fTBC
STCK
000
001
010
011
100
101
110
111
Comparator P �atch
3-bit Comparator P
ST�PF Interrupt
STOC
b7~b9
STON
STPAU
STCCLR
b0~b9
10-bit Comparator A
STCK�~STCK0
STP
STPB
Output
Control
Polarit�
Control
Pin
Control
ST�1� ST�0
STIO1� STIO0
STPOL
PASn�PBSn
Counter Clear 0
1
10-bit Count-up Counter
Comparator A �atch
ST�AF Interrupt
STIO1� STIO0
Edge
Detector
CCRA
STPI
Standard Type TM Block Diagram
Standard TM Operation
At its core is a 10-bit count-up counter which is driven by a user selectable internal clock source.
There are also two internal comparators with the names, Comparator A and Comparator P. These
comparators will compare the value in the counter with CCRP and CCRA registers. The CCRP is 3-bit
wide whose value is compared with the highest 3 bits in the counter while the CCRA is the 10 bits
and therefore compares with all counter bits.
The only way of changing the value of the 10-bit counter using the application program, is to clear the
counter by changing the STON bit from low to high. The counter will also be cleared automatically
by a counter overflow or a compare match with one of its associated comparators. When these
conditions occur, a TM interrupt signal will also usually be generated. The Standard Type TM can
operate in a number of different operational modes, can be driven by different clock sources and can
also control an output pin. All operating setup conditions are selected using relevant internal registers.
Standard Type TM Register Description
Overall operation of the Standard TM is controlled using series of registers. A read only register
pair exists to store the internal counter 10-bit value, while a read/write register pair exists to store
the internal 10-bit CCRA value. The remaining two registers are control registers which setup the
different operating and control modes as well as three CCRP bits.
Bit
Register
Name
7
6
5
4
3
2
1
0
STMC0
STPAU
STCK2
STCK1
STCK0
STON
STRP2
STRP1
STRP0
STMC1
STM1
STM0
STIO1
STIO0
STOC
STPOL
STDPX
STCCLR
STMDL
D7
D6
D5
D4
D3
D2
D1
D0
STMDH
—
—
—
—
—
—
D9
D8
STMAL
D7
D6
D5
D4
D3
D2
D1
D0
STMAH
—
—
—
—
—
—
D9
D8
10-bit Standard TM Register List
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STMC0 Register
Bit
7
6
5
4
3
2
1
0
Name
STPAU
STCK2
STCK1
STCK0
STON
STRP2
STRP1
STRP0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7STPAU: STM Counter Pause Control
0: Run
1: Pause
The counter can be paused by setting this bit high. Clearing the bit to zero restores
normal counter operation. When in a Pause condition the STM will remain powered
up and continue to consume power. The counter will retain its residual value when
this bit changes from low to high and resume counting from this value when the bit
changes to a low value again.
Bit 6~4STCK2~STCK0: Select STM Counter clock
000: fSYS/4
001: fSYS
010: fH/16
011: fH/64
100: fTBC
101: fTBC
110: STCK rising edge clock
111: STCK falling edge clock
These three bits are used to select the clock source for the STM. The external pin clock
source can be chosen to be active on the rising or falling edge. The clock source fSYS is
the system clock, while fH and fTBC are other internal clocks, the details of which can
be found in the oscillator section.
Bit 3STON: STM Counter On/Off Control
0: Off
1: On
This bit controls the overall on/off function of the STM. Setting the bit high enables
the counter to run, clearing the bit disables the STM. Clearing this bit to zero will
stop the counter from counting and turn off the STM which will reduce its power
consumption. When the bit changes state from low to high the internal counter value
will be reset to zero, however when the bit changes from high to low, the internal
counter will retain its residual value until the bit returns high again. If the STM is in
the Compare Match Output Mode or the PWM output Mode or Single Pulse Output
Mode then the STM output pin will be reset to its initial condition, as specified by the
STOC bit, when the STON bit changes from low to high.
Bit 2~0STRP2~STRP0: STM CCRP 3-bit register, compared with the STM Counter bit 9~bit 7
Comparator P Match Period
000: 1024 STM clocks
001: 128 STM clocks
010: 256 STM clocks
011: 384 STM clocks
100: 512 STM clocks
101: 640 STM clocks
110: 768 STM clocks
111: 896 STM clocks
These three bits are used to setup the value on the internal CCRP 3-bit register, which
are then compared with the internal counter’s highest three bits. The result of this
comparison can be selected to clear the internal counter if the STCCLR bit is set to
zero. Setting the STCCLR bit to zero ensures that a compare match with the CCRP
values will reset the internal counter. As the CCRP bits are only compared with the
highest three counter bits, the compare values exist in 128 clock cycle multiples.
Clearing all three bits to zero is in effect allowing the counter to overflow at its
maximum value.
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STMC1 Register
Bit
7
6
5
4
3
2
1
0
Name
STM1
STM0
STIO1
STIO0
STOC
STPOL
STDPX
STCCLR
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~6STM1~STM0: Select STM Operating Mode
00: Compare Match Output Mode
01: Capture Input Mode
10: PWM output Mode or Single Pulse Output Mode
11: Timer/Counter Mode
These bits setup the required operating mode for the STM. To ensure reliable operation
the STM should be switched off before any changes are made to the STM1 and STM0
bits. In the Timer/Counter Mode, the STM output pin state is undefined.
Bit 5~4STIO1~STIO0: Select STM function
Compare Match Output Mode
00: No change
01: Output low
10: Output high
11: Toggle output
PWM output Mode/ Single Pulse Output Mode
00: PWM Output inactive state
01: PWM Output active state
10: PWM output
11: Single pulse output
Capture Input Mode
00: Input capture at rising edge of STPI
01: Input capture at falling edge of STPI
10: Input capture at falling/rising edge of STPI
11: Input capture disabled
Timer/counter Mode
Unused
These two bits are used to determine how the TM output pin changes state when a
certain condition is reached. The function that these bits select depends upon in which
mode the TM is running.
In the Compare Match Output Mode, the STIO1~STIO0 bits determine how the TM
output pin changes state when a compare match occurs from the Comparator A. The
TM output pin can be setup to switch high, switch low or to toggle its present state
when a compare match occurs from the Comparator A. When the STIO1~STIO0 bits
are both zero, then no change will take place on the output. The initial value of the TM
output pin should be setup using the STOC bit. Note that the output level requested by
the STIO1~STIO0 bits must be different from the initial value setup using the STOC
bit otherwise no change will occur on the TM output pin when a compare match
occurs. After the TM output pin changes state it can be reset to its initial level by
changing the level of the STON bit from low to high.
In the PWM Mode, the STIO1 and STIO0 bits determine how the TM output pin
changes state when a certain compare match condition occurs. The PWM output
function is modified by changing these two bits. It is necessary to change the values
of the STIO1 and STIO0 bits only after the TM has been switched off. Unpredictable
PWM outputs will occur if the STIO1 and STIO0 bits are changed when the TM is
running.
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Bit 3STOC: STM Output control bit
Compare Match Output Mode
0: Initial low
1: Initial high
PWM output Mode/ Single Pulse Output Mode
0: Active low
1: Active high
This is the output control bit for the STM output pin. Its operation depends upon
whether STM is being used in the Compare Match Output Mode or in the PWM
output Mode/ Single Pulse Output Mode. It has no effect if the STM is in the Timer/
Counter Mode. In the Compare Match Output Mode it determines the logic level
of the STM output pin before a compare match occurs. In the PWM output Mode it
determines if the PWM signal is active high or active low. In the Single Pulse Output
Mode it determines the logic level of the STM output pin when the STON bit changes
from low to high.
Bit 2STPOL: STM Output polarity Control
0: Non-invert
1: Invert
This bit controls the polarity of the STM output pin. When the bit is set high the STM
output pin will be inverted and not inverted when the bit is zero. It has no effect if the
STM is in the Timer/Counter Mode.
Bit 1STDPX: STM PWM period/duty Control
0: CCRP - period; CCRA - duty
1: CCRP - duty; CCRA - period
This bit, determines which of the CCRA and CCRP registers are used for period and
duty control of the PWM waveform.
Bit 0STCCLR: Select STM Counter clear condition
0: STM Comparator P match
1: STM Comparator A match
This bit is used to select the method which clears the counter. Remember that the
Standard STM contains two comparators, Comparator A and Comparator P, either of
which can be selected to clear the internal counter. With the STCCLR bit set high,
the counter will be cleared when a compare match occurs from the Comparator A.
When the bit is low, the counter will be cleared when a compare match occurs from
the Comparator P or with a counter overflow. A counter overflow clearing method can
only be implemented if the CCRP bits are all cleared to zero. The STCCLR bit is not
used in the PWM output mode, Single Pulse or Input Capture Mode.
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STMDL Register
Bit
7
6
5
4
3
2
1
0
Name
D7
D6
D5
D4
D3
D2
D1
D0
R/W
R
R
R
R
R
R
R
R
POR
0
0
0
0
0
0
0
0
Bit 7~0
STM Counter Low Byte Register bit 7~bit 0
STM 10-bit Counter bit 7~bit 0
STMDH Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
—
—
D9
D8
R/W
—
—
—
—
—
—
R
R
POR
—
—
—
—
—
—
0
0
3
2
1
0
Bit 7~2
Unimplemented, read as “0”
Bit 1~0
STM Counter High Byte Register bit 1~bit 0
STM 10-bit Counter bit 9~bit 8
STMAL Register
Bit
7
6
5
4
Name
D7
D6
D5
D4
D3
D2
D1
D0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~0
STM CCRA Low Byte Register bit 7~bit 0
STM 10-bit Counter bit 7~bit 0
STMAH Register
Rev. 1.00
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
—
—
D9
D8
R/W
—
—
—
—
—
—
R/W
R/W
POR
—
—
—
—
—
—
0
0
Bit 7~2
Unimplemented, read as “0”
Bit 1~0
STM CCRA High Byte Register bit 1~bit 0
STM 10-bit Counter bit 9~bit 8
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Standard Type TM Operating Modes
The Standard Type TM can operate in one of five operating modes, Compare Match Output Mode,
PWM Output Mode, Single Pulse Output Mode, Capture Input Mode or Timer/Counter Mode. The
operating mode is selected using the STM1 and STM0 bits in the STMC1 register.
Compare Match Output Mode
To select this mode, bits STM1 and STM0 in the STMC1 register, should be set to 00 respectively.
In this mode once the counter is enabled and running it can be cleared by three methods. These are
a counter overflow, a compare match from Comparator A and a compare match from Comparator P.
When the STCCLR bit is low, there are two ways in which the counter can be cleared. One is when
a compare match from Comparator P, the other is when the CCRP bits are all zero which allows the
counter to overflow. Here both STMAF and STMPF interrupt request flags for Comparator A and
Comparator P respectively, will both be generated.
If the STCCLR bit in the STMC1 register is high then the counter will be cleared when a compare
match occurs from Comparator A. However, here only the STMAF interrupt request flag will be
generated even if the value of the CCRP bits is less than that of the CCRA registers. Therefore when
STCCLR is high no STMPF interrupt request flag will be generated. In the Compare Match Output
Mode, the CCRA can not be set to “0”. If the CCRA bits are all zero, the counter will overflow when
its reaches its maximum 10-bit, 3FF Hex, value, however here the STMAF interrupt request flag
will not be generated.
As the name of the mode suggests, after a comparison is made, the STM output pin, will change
state. The STM output pin condition however only changes state when an STMAF interrupt request
flag is generated after a compare match occurs from Comparator A. The STMPF interrupt request
flag, generated from a compare match occurs from Comparator P, will have no effect on the STM
output pin. The way in which the STM output pin changes state are determined by the condition of
the STIO1 and STIO0 bits in the STMC1 register. The STM output pin can be selected using the
STIO1 and STIO0 bits to go high, to go low or to toggle from its present condition when a compare
match occurs from Comparator A. The initial condition of the STM output pin, which is setup after
the STON bit changes from low to high, is setup using the STOC bit. Note that if the STIO1 and
STIO0 bits are zero then no pin change will take place.
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STCCLR = 0; STM [1:0] = 00
Counter overflow
Counter Value
CCRP > 0
Counter cleared by CCRP value
CCRP=0
0x3FF
CCRP > 0
Counter
Restart
Resume
CCRP
Pause
CCRA
Stop
Time
STON
STPAU
STPOL
CCRP Int.
flag STMPF
CCRA Int.
flag STMAF
STM O/P Pin
Output pin set
to initial Level
Low if STOC=0
Output not affected by
STMAF flag. Remains High
until reset by STON bit
Output Toggle
with STMAF flag
Here STIO [1:0] = 11
Toggle Output select
Note STIO [1:0] = 10
Active High Output select
Output Inverts
when STPOL is high
Output Pin
Reset to Initial value
Output controlled by
other pin-shared function
Compare Match Output Mode – STCCLR=0
Note: 1. With STCCLR=0 a Comparator P match will clear the counter
2. The TM output pin controlled only by the STMAF flag
3. The output pin reset to initial state by a STON bit rising edge
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Counter Value
STCCLR = 1; STM [1:0] = 00
CCRA = 0
Counter overflow
CCRA > 0 Counter cleared by CCRA value
0x3FF
CCRA=0
Resume
CCRA
Pause
Stop
Counter Restart
CCRP
Time
STON
STPAU
STPOL
No STMAF flag
generated on
CCRA overflow
CCRA Int.
flag STMAF
CCRP Int.
flag STMPF
STM O/P Pin
Output
does not
change
STMPF not
generated
Output pin set
to initial Level
Low if STOC=0
Output Toggle
with STMAF flag
Here STIO [1:0] = 11
Toggle Output select
Output not affected by
STMAF flag. Remains High
until reset by STON bit
Note STIO [1:0] = 10
Active High Output select
Output Inverts
when STPOL is high
Output Pin
Reset to Initial value
Output controlled by
other pin-shared function
Compare Match Output Mode – STCCLR=1
Note: 1. With STCCLR=1 a Comparator A match will clear the counter
2. The TM output pin controlled only by the STMAF flag
3. The output pin reset to initial state by a STON rising edge
4. The STMPF flag is not generated when STCCLR=1
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Timer/Counter Mode
To select this mode, bits STM1 and STM0 in the STMC1 register should be set to 11 respectively.
The Timer/Counter Mode operates in an identical way to the Compare Match Output Mode
generating the same interrupt flags. The exception is that in the Timer/Counter Mode the STM
output pin is not used. Therefore the above description and Timing Diagrams for the Compare
Match Output Mode can be used to understand its function. As the STM output pin is not used in
this mode, the pin can be used as a normal I/O pin or other pin-shared function by setting pin-share
function register.
PWM Output Mode
To select this mode, bits STM1 and STM0 in the STMC1 register should be set to 10 respectively
and also the STIO1 and STIO0 bits should be set to 10 respectively. The PWM function within
the STM is useful for applications which require functions such as motor control, heating control,
illumination control etc. By providing a signal of fixed frequency but of varying duty cycle on the
STM output pin, a square wave AC waveform can be generated with varying equivalent DC RMS
values.
As both the period and duty cycle of the PWM waveform can be controlled, the choice of generated
waveform is extremely flexible. In the PWM output mode, the STCCLR bit has no effect as the
PWM period. Both of the CCRA and CCRP registers are used to generate the PWM waveform, one
register is used to clear the internal counter and thus control the PWM waveform frequency, while
the other one is used to control the duty cycle. Which register is used to control either frequency
or duty cycle is determined using the STDPX bit in the STMC1 register. The PWM waveform
frequency and duty cycle can therefore be controlled by the values in the CCRA and CCRP registers.
An interrupt flag, one for each of the CCRA and CCRP, will be generated when a compare match
occurs from either Comparator A or Comparator P. The STOC bit in the STMC1 register is used to
select the required polarity of the PWM waveform while the two STIO1 and STIO0 bits are used to
enable the PWM output or to force the STM output pin to a fixed high or low level. The STPOL bit
is used to reverse the polarity of the PWM output waveform.
• 10-bit STM, PWM Output Mode, Edge-aligned Mode, STDPX=0
CCRP
001b
010b
011b
100b
101b
110b
111b
000b
Period
128
256
384
512
640
768
896
1024
Duty
CCRA
If fSYS=8MHz, TM clock source is fSYS/4, CCRP=100b and CCRA=128,
The STM PWM output frequency=(fSYS/4) / 512=fSYS/2048=3.90625kHz, duty=128/512=25%.
If the Duty value defined by the CCRA register is equal to or greater than the Period value, then the
PWM output duty is 100%.
• 10-bit STM, PWM Output Mode, Edge-aligned Mode, STDPX=1
CCRP
001b
010b
011b
100b
Period
Duty
101b
110b
111b
000b
768
896
1024
CCRA
128
256
384
512
640
The PWM output period is determined by the CCRA register value together with the STM clock
while the PWM duty cycle is defined by the CCRP register value.
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Cost-Effective 8-Bit Flash MCU with EEPROM
Counter Value
STDPX = 0; STM [1:0] = 10
Counter cleared
by CCRP
Counter Reset when
STON returns high
CCRP
Pause Resume
CCRA
Counter Stop if
STON bit low
Time
STON
STPAU
STPOL
CCRA Int.
flag STMAF
CCRP Int.
flag STMPF
STM O/P Pin
(STOC=1)
STM O/P Pin
(STOC=0)
PWM Duty Cycle
set by CCRA
PWM Period
set by CCRP
PWM resumes
operation
Output controlled by
Output Inverts
other pin-shared function
when STPOL = 1
PWM Output Mode – STDPX=0
Note: 1. Here STDPX=0 - Counter cleared by CCRP
2. A counter clear sets PWM Period
3. The internal PWM function continues running even when STIO[1:0]=00 or 01
4. The STCCLR bit has no influence on PWM operation
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Cost-Effective 8-Bit Flash MCU with EEPROM
Counter Value
STDPX = 1; STM [1:0] = 10
Counter cleared
by CCRA
Counter Reset when
STON returns high
CCRA
Pause Resume
CCRP
Counter Stop if
STON bit low
Time
STON
STPAU
STPOL
CCRP Int.
flag STMPF
CCRA Int.
flag STMAF
STM O/P
Pin (STOC=1)
STM O/P
Pin (STOC=0)
PWM resumes
operation
PWM Duty Cycle
set by CCRP
PWM Period
set by CCRA
Output controlled by
other pin-shared function
Output Inverts
when STPOL = 1
PWM Output Mode – STDPX=1
Note: 1. Here STDPX=1 - Counter cleared by CCRA
2. A counter clear sets PWM Period
3. The internal PWM function continues even when STIO[1:0]=00 or 01
4. The STCCLR bit has no influence on PWM operation
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Cost-Effective 8-Bit Flash MCU with EEPROM
Single Pulse Mode
To select this mode, bits STM1 and STM0 in the STMC1 register should be set to 10 respectively
and also the STIO1 and STIO0 bits should be set to 11 respectively. The Single Pulse Output Mode,
as the name suggests, will generate a single shot pulse on the STM output pin.
The trigger for the pulse output leading edge is a low to high transition of the STON bit, which can
be implemented using the application program. However in the Single Pulse Mode, the STON bit
can also be made to automatically change from low to high using the external STCK pin, which will
in turn initiate the Single Pulse output. When the STON bit transitions to a high level, the counter
will start running and the pulse leading edge will be generated. The STON bit should remain high
when the pulse is in its active state. The generated pulse trailing edge will be generated when the
STON bit is cleared to zero, which can be implemented using the application program or when a
compare match occurs from Comparator A.
Leading Edge
Trailing Edge
STON bit
0
1
STON bit
1
0
S/W Command
SET“STON”
or
STCK Pin
Transition
S/W Command
CLR“STON”
or
CCRA Compare
�atch
STP/STPB Output Pin
Pulse Width = CCRA Value
Single Pulse Generation
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Cost-Effective 8-Bit Flash MCU with EEPROM
Counter Value
STM [1:0] = 10 ; STIO [1:0] = 11
Counter stopped
by CCRA
Counter Reset when
STON returns high
CCRA
Pause
Counter Stops
by software
Resume
CCRP
Time
STON
Software
Trigger
Auto. set by
STCK pin
Cleared by
CCRA match
STCK pin
Software
Trigger
Software
Clear
Software
Trigger
Software
Trigger
STCK pin
Trigger
STPAU
STPOL
No CCRP Interrupts
generated
CCRP Int. Flag
STMPF
CCRA Int. Flag
STMAF
STM O/P Pin
(STOC=1)
STM O/P Pin
(STOC=0)
Output Inverts
when STPOL = 1
Pulse Width
set by CCRA
Single Pulse Mode
Note: 1. Counter stopped by CCRA match
2. CCRP is not used
3. The pulse is triggered by setting the STON bit high
4. In the Single Pulse Mode, STIO [1:0] must be set to “11” and can not be changed.
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Cost-Effective 8-Bit Flash MCU with EEPROM
However a compare match from Comparator A will also automatically clear the STON bit and thus
generate the Single Pulse output trailing edge. In this way the CCRA value can be used to control the
pulse width. A compare match from Comparator A will also generate a STM interrupt. The counter
can only be reset back to zero when the STON bit changes from low to high when the counter
restarts. In the Single Pulse Mode CCRP is not used. The STCCLR and STDPX bits are not used in
this Mode.
Capture Input Mode
To select this mode bits STM1 and STM0 in the STMC1 register should be set to 01 respectively.
This mode enables external signals to capture and store the present value of the internal counter
and can therefore be used for applications such as pulse width measurements. The external signal
is supplied on the STPI, whose active edge can be either a rising edge, a falling edge or both rising
and falling edges; the active edge transition type is selected using the STIO1 and STIO0 bits in
the STMC1 register. The counter is started when the STON bit changes from low to high which is
initiated using the application program.
When the required edge transition appears on the STPI the present value in the counter will be
latched into the CCRA registers and a STM interrupt generated. Irrespective of what events occur on
the STPI the counter will continue to free run until the STON bit changes from high to low. When a
CCRP compare match occurs the counter will reset back to zero; in this way the CCRP value can be
used to control the maximum counter value. When a CCRP compare match occurs from Comparator
P, a STM interrupt will also be generated. Counting the number of overflow interrupt signals from
the CCRP can be a useful method in measuring long pulse widths. The STIO1 and STIO0 bits can
select the active trigger edge on the STPI to be a rising edge, falling edge or both edge types. If
the STIO1 and STIO0 bits are both set high, then no capture operation will take place irrespective
of what happens on the STPI, however it must be noted that the counter will continue to run.The
STCCLR and STDPX bits are not used in this Mode.
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Cost-Effective 8-Bit Flash MCU with EEPROM
Counter Value
STM [1:0] = 01
Counter cleared by
CCRP
Counter
Stop
Counter
Reset
CCRP
YY
Pause
Resume
XX
Time
STON
STPAU
Active
edge
Active
edge
Active
edge
STM capture
pin STPI
CCRA Int.
Flag STMAF
CCRP Int.
Flag STMPF
CCRA
Value
STIO [1:0]
Value
XX
00 – Rising edge
YY
01 – Falling edge
XX
10 – Both edges
YY
11 – Disable Capture
Capture Input Mode
Note: 1. STM[1:0]=01 and active edge set by the STIO[1:0] bits
2. A TM Capture input pin active edge transfers the counter value to CCRA
3. The STCCLR and STDPX bits are not used
4. No output function – STOC and STPOL bits are not used
5. CCRP determines the counter value and the counter has a maximum count value when CCRP is equal to
zero.
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Cost-Effective 8-Bit Flash MCU with EEPROM
Periodic Type TM – PTM
The Periodic Type TM contains five operating modes, which are Compare Match Output, Timer/
Event Counter, Capture Input, Single Pulse Output and PWM Output modes. The Periodic TM can
also be controlled with two external input pins and can drive two external output pins.
Device
HT66F302/HT66F303
Name
TM Input Pin
TM Output Pin
10-bit PTM
PTCK, PTPI
PTP, PTPB
Note: For the HT66F302, the PTP and PTPB pins are not bonded to external pins.
Periodic TM Operation
At its core is a 10-bit count-up counter which is driven by a user selectable internal or external clock
source. There are two internal comparators with the names, Comparator A and Comparator P. These
comparators will compare the value in the counter with the CCRA and CCRP registers.
The only way of changing the value of the 10-bit counter using the application program, is to
clear the counter by changing the PTON bit from low to high. The counter will also be cleared
automatically by a counter overflow or a compare match with one of its associated comparators.
When these conditions occur, a TM interrupt signal will also usually be generated. The Periodic
Type TM can operate in a number of different operational modes, can be driven by different clock
sources including an input pin and can also control the output pin. All operating setup conditions are
selected using relevant internal registers.
CCRP
fSYS/4
fSYS
fH/1�
fH/�4
fTBC
fTBC
PTCK
000
001
010
011
100
101 PTON
110 PTPAU
111
PTCK�~PTCK0
10-bit Comparator P
Comparator P �atch
PT�PF Interrupt
PTOC
b0~b9
10-bit Count-up Counter
PTCCLR
b0~b9
10-bit Comparator A
CCRA
Output
Control
Polarit�
Control
Pin
Control
PT�1� PT�0
PTIO1� PTIO0
PTPOL
PBSn
Counter Clear 0
1
Comparator A �atch
PTP
PTPB
PT�AF Interrupt
PTIO1� PTIO0
PTCKS
Edge
Detector
0
1
PTPI
Periodic Type TM Block Diagram
Periodic Type TM Register Description
Overall operation of the Periodic TM is controlled using a series of registers. A read only register
pair exists to store the internal counter 10-bit value, while two read/write register pairs exist to store
the internal 10-bit CCRA and CCRP value. The remaining two registers are control registers which
setup the different operating and control modes.
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Bit
Register
Name
7
6
5
4
PTMC0
PTPAU
PTCK2
PTCK1
PTCK0
PTON
—
—
—
PTMC1
PTM1
PTM0
PTIO1
PTIO0
PTOC
PTPOL
PTCKS
PTCCLR
D0
3
2
1
0
PTMDL
D7
D6
D5
D4
D3
D2
D1
PTMDH
—
—
—
—
—
—
D9
D8
PTMAL
D7
D6
D5
D4
D3
D2
D1
D0
PTMAH
—
—
—
—
—
—
D9
D8
PTMRPL
D7
D6
D5
D4
D3
D2
D1
D0
PTMRPH
—
—
—
—
—
—
D9
D8
10-bit Periodic TM Register List
PTMC0 Register
Bit
7
6
5
4
3
2
1
0
Name
PTPAU
PTCK2
PTCK1
PTCK0
PTON
—
—
—
R/W
R/W
R/W
R/W
R/W
R/W
—
—
—
POR
0
0
0
0
0
—
—
—
Bit 7PTPAU: PTM Counter Pause Control
0: run
1: pause
The counter can be paused by setting this bit high. Clearing the bit to zero restores
normal counter operation. When in a Pause condition the TM will remain powered up
and continue to consume power. The counter will retain its residual value when this bit
changes from low to high and resume counting from this value when the bit changes
to a low value again.
Bit 6~4PTCK2~PTCK0: Select PTM Counter clock
000: fSYS/4
001: fSYS
010: fH/16
011: fH/64
100: fTBC
101: fTBC
110: PTCK rising edge clock
111: PTCK falling edge clock
These three bits are used to select the clock source for the TM. The external pin clock
source can be chosen to be active on the rising or falling edge. The clock source fSYS is
the system clock, while fTBC is another internal clock, the details of which can be found
in the oscillator section.
Bit 3PTON: PTM Counter On/Off Control
0: Off
1: On
This bit controls the overall on/off function of the TM. Setting the bit high enables the
counter to run, clearing the bit disables the TM. Clearing this bit to zero will stop the
counter from counting and turn off the TM which will reduce its power consumption.
When the bit changes state from low to high the internal counter value will be reset to
zero, however when the bit changes from high to low, the internal counter will retain
its residual value until the bit returns high again.
If the TM is in the Compare Match Output Mode then the TM output pin will be reset
to its initial condition, as specified by the TM Output control bit, when the bit changes
from low to high.
Bit 2~0
Rev. 1.00
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Cost-Effective 8-Bit Flash MCU with EEPROM
PTMC1 Register
Bit
7
6
5
4
3
2
1
0
Name
PTM1
PTM0
PTIO1
PTIO0
PTOC
PTPOL
PTCKS
PTCCLR
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~6PTM1~PTM0: Select PTM Operation Mode
00: Compare Match Output Mode
01: Capture Input Mode
10: PWM Mode or Single Pulse Output Mode
11: Timer/Counter Mode
These bits setup the required operating mode for the TM. To ensure reliable operation
the TM should be switched off before any changes are made to the PTM1 and PTM0
bits. In the Timer/Counter Mode, the PTM output pin state is undefined.
Bit 5~4PTIO1~PTIO0: Select PTM output function
Compare Match Output Mode
00: No change
01: Output low
10: Output high
11: Toggle output
PWM Mode/Single Pulse Output Mode
00: PWM Output inactive state
01: PWM Output active state
10: PWM output
11: Single pulse output
Capture Input Mode
00: Input capture at rising edge of PTPI
01: Input capture at falling edge of PTPI
10: Input capture at falling/rising edge of PTPI
11: Input capture disabled
Timer/counter Mode
Unused
These two bits are used to determine how the TM output pin changes state when a
certain condition is reached. The function that these bits select depends upon in which
mode the TM is running.
In the Compare Match Output Mode, the PTIO1 and PTIO0 bits determine how the
TM output pin changes state when a compare match occurs from the Comparator A.
The TM output pin can be setup to switch high, switch low or to toggle its present state
when a compare match occurs from the Comparator A. When these bits are both zero,
then no change will take place on the output. The initial value of the TM output pin
should be setup using the PTOC bit. Note that the output level requested by the PTIO1
and PTIO0 bits must be different from the initial value setup using the PTOC bit
otherwise no change will occur on the TM output pin when a compare match occurs.
After the TM output pin changes state, it can be reset to its initial level by changing
the level of the PTON bit from low to high.
In the PWM Mode, the PTIO1 and PTIO0 bits determine how the TM output pin
changes state when a certain compare match condition occurs. The PWM output
function is modified by changing these two bits. It is necessary to change the values
of the PTIO1 and PTIO0 bits only after the TM has been switched off. Unpredictable
PWM outputs will occur if the PTIO1 and PTIO0 bits are changed when the TM is
running.
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Cost-Effective 8-Bit Flash MCU with EEPROM
Bit 3PTOC: PTP/PTPB Output control bit
Compare Match Output Mode
0: Initial low
1: Initial high
PWM Mode/ Single Pulse Output Mode
0: Active low
1: Active high
This is the output control bit for the TM output pin. Its operation depends upon
whether TM is being used in the Compare Match Output Mode or in the PWM Mode/
Single Pulse Output Mode. It has no effect if the TM is in the Timer/Counter Mode. In
the Compare Match Output Mode it determines the logic level of the TM output pin
before a compare match occurs. In the PWM Mode it determines if the PWM signal is
active high or active low.
Bit 2PTPOL: PTP/PTPB Output polarity Control
0: non-invert
1: invert
This bit controls the polarity of the PTP/PTPB output pin. When the bit is set high the
TM output pin will be inverted and not inverted when the bit is zero. It has no effect if
the TM is in the Timer/Counter Mode.
Bit 1PTCKS: PTM capture trigger source select
0: From PTPI
1: From PTCK pin
Bit 0PTCCLR: Select PTM Counter clear condition
0: PTM Comparatror P match
1: PTM Comparatror A match
This bit is used to select the method which clears the counter. Remember that the
Periodic TM contains two comparators, Comparator A and Comparator P, either of
which can be selected to clear the internal counter. With the PTCCLR bit set high,
the counter will be cleared when a compare match occurs from the Comparator A.
When the bit is low, the counter will be cleared when a compare match occurs from
the Comparator P or with a counter overflow. A counter overflow clearing method can
only be implemented if the CCRP bits are all cleared to zero. The PTCCLR bit is not
used in the PWM, Single Pulse or Input Capture Mode.
PTMDL Register
Bit
7
6
5
4
3
2
1
0
Name
D7
D6
D5
D4
D3
D2
D1
D0
R/W
R
R
R
R
R
R
R
R
POR
0
0
0
0
0
0
0
0
Bit 7~0PTMDL: PTM Counter Low Byte Register bit 7~bit 0
PTM 10-bit Counter bit 7~bit 0
PTMDH Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
—
—
D9
D8
R/W
—
—
—
—
—
—
R
R
POR
—
—
—
—
—
—
0
0
Bit 7~2
Unimplemented, read as "0"
Bit 1~0PTMDH: PTM Counter High Byte Register bit 1~bit 0
PTM 10-bit Counter bit 9~bit 8
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Cost-Effective 8-Bit Flash MCU with EEPROM
PTMAL Register
Bit
7
6
5
4
3
2
1
0
Name
D7
D6
D5
D4
D3
D2
D1
D0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~0PTMAL: PTM CCRA Low Byte Register bit 7~bit 0
PTM 10-bit CCRA bit 7~bit 0
PTMAH Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
—
—
D9
D8
R/W
—
—
—
—
—
—
R/W
R/W
POR
—
—
—
—
—
—
0
0
2
1
0
Bit 7~2
Unimplemented, read as "0"
Bit 1~0PTMAH: PTM CCRA High Byte Register bit 1~bit 0
PTM 10-bit CCRA bit 9~bit 8
PTMRPL Register
Bit
7
6
5
4
3
Name
D7
D6
D5
D4
D3
D2
D1
D0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~0PTMRPL: PTM CCRP Low Byte Register bit 7~bit 0
PTM 10-bit CCRP bit 7~bit 0
PTMRPH Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
—
—
D9
D8
R/W
—
—
—
—
—
—
R/W
R/W
POR
—
—
—
—
—
—
0
0
Bit 7~2
Unimplemented, read as "0"
Bit 1~0PTMRPH: PTM CCRP High Byte Register bit 1~bit 0
PTM 10-bit CCRP bit 9~bit 8
Rev. 1.00
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Cost-Effective 8-Bit Flash MCU with EEPROM
Periodic Type TM Operating Modes
The Periodic Type TM can operate in one of five operating modes, Compare Match Output Mode,
PWM Output Mode, Single Pulse Output Mode, Capture Input Mode or Timer/Counter Mode. The
operating mode is selected using the PTM1 and PTM0 bits in the PTMC1 register.
Compare Match Output Mode
To select this mode, bits PTM1 and PTM0 in the PTMC1 register, should be all cleared to 00
respectively. In this mode once the counter is enabled and running it can be cleared by three
methods. These are a counter overflow, a compare match from Comparator A and a compare match
from Comparator P. When the PTCCLR bit is low, there are two ways in which the counter can
be cleared. One is when a compare match occurs from Comparator P, the other is when the CCRP
bits are all zero which allows the counter to overflow. Here both the PTMAF and PTMPF interrupt
request flags for Comparator Aand Comparator P respectively, will both be generated.
If the PTCCLR bit in the PTMC1 register is high then the counter will be cleared when a compare
match occurs from Comparator A. However, here only the PTMAF interrupt request flag will be
generated even if the value of the CCRP bits is less than that of the CCRA registers. Therefore when
PTCCLR is high no PTMPF interrupt request flag will be generated. In the Compare Match Output
Mode, the CCRA can not be set to “0”. If the CCRA bits are all zero, the counter will overflow when
its reaches its maximum 10-bit, 3FF Hex, value, however here the PTMAF interrupt request flag
will not be generated.
As the name of the mode suggests, after a comparison is made, the TM output pin, will change state.
The TM output pin condition however only changes state when a PTMAF interrupt request flag is
generated after a compare match occurs from Comparator A. The PTMPF interrupt request flag,
generated from a compare match from Comparator P, will have no effect on the TM output pin. The
way in which the TM output pin changes state are determined by the condition of the PTIO1 and
PTIO0 bits in the PTMC1 register. The TM output pin can be selected using the PTIO1 and PTIO0
bits to go high, to go low or to toggle from its present condition when a compare match occurs from
Comparator A. The initial condition of the TM output pin, which is setup after the PTON bit changes
from low to high, is setup using the PTOC bit. Note that if the PTIO1, PTIO0 bits are zero then no
pin change will take place.
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Cost-Effective 8-Bit Flash MCU with EEPROM
Counter overflow
Counter Value
0x3FF
PTCCLR = 0; PTM [1:0] = 00
CCRP > 0
Counter cleared by CCRP value
CCRP=0
CCRP > 0
Counter
Restart
Resume
CCRP
Pause
CCRA
Stop
Time
PTON
PTPAU
PTPOL
CCRP Int. Flag
PTMPF
CCRA Int. Flag
PTMAF
PTM O/P Pin
Output pin set
to initial Level
Low if PTOC=0
Output not affected by
PTMAF flag. Remains High
until reset by PTON bit
Output Toggle
with PTMAF flag
Here PTIO [1:0] = 11
Toggle Output select
Note PTIO [1:0] = 10
Active High Output
select
Output Inverts
when PTPOL is high
Output Pin
Reset to Initial value
Output controlled by other
pin-shared function
Compare Match Output Mode – PTCCLR=0
Note: 1. With PTCCLR=0 – a Comparator P match will clear the counter
2. The TM output pin is controlled only by the PTMAF flag
3. The output pin is reset to initial state by a PTON bit rising edge
Rev. 1.00
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Cost-Effective 8-Bit Flash MCU with EEPROM
Counter Value
PTCCLR = 1; PTM [1:0] = 00
CCRA = 0
Counter overflow
CCRA > 0 Counter cleared by CCRA value
0x3FF
CCRA=0
Resume
CCRA
Pause
Stop
Counter Restart
CCRP
Time
PTON
PTPAU
PTPOL
No PTMAF flag
generated on
CCRA overflow
CCRA Int.
Flag PTMAF
CCRP Int.
Flag PTMPF
PTMPF not
generated
Output does
not change
PTM O/P Pin
Output pin set
to initial Level
Low if PTOC=0
Output Toggle
with PTMAF flag
Here PTIO [1:0] = 11
Toggle Output select
Output not affected by
PTMAF flag. Remains High
until reset by PTON bit
Note PTIO [1:0] = 10
Active High Output select
Output Inverts
when PTPOL is high
Output Pin
Reset to Initial value
Output controlled by
other pin-shared function
Compare Match Output Mode – PTCCLR=1
Note: 1. With PTCCLR=1 – a Comparator A match will clear the counter
2. The TM output pin is controlled only by the PTMAF flag
3. The output pin is reset to initial state by a PTON rising edge
4. The PTMPF flag is not generated when PTCCLR=1
Rev. 1.00
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Cost-Effective 8-Bit Flash MCU with EEPROM
Timer/Counter Mode
To select this mode, bits PTM1 and PTM0 in the PTMC1 register should all be set to 11 respectively.
The Timer/Counter Mode operates in an identical way to the Compare Match Output Mode
generating the same interrupt flags. The exception is that in the Timer/Counter Mode the TM output
pin is not used. Therefore the above description and Timing Diagrams for the Compare Match
Output Mode can be used to understand its function. As the TM output pin is not used in this mode,
the pin can be used as a normal I/O pin or other pin-shared function.
PWM Output Mode
To select this mode, bits PTM1 and PTM0 in the PTMC1 register should be set to 10 respectively
and also the PTIO1 and PTIO0 bits should be set to 10 respectively. The PWM function within
the TM is useful for applications which require functions such as motor control, heating control,
illumination control etc. By providing a signal of fixed frequency but of varying duty cycle on the
TM output pin, a square wave AC waveform can be generated with varying equivalent DC RMS
values.
As both the period and duty cycle of the PWM waveform can be controlled, the choice of generated
waveform is extremely flexible. In the PWM mode, the PTCCLR bit has no effect as the PWM
period. Both of the CCRP and CCRA registers are used to generate the PWM waveform, one register
is used to clear the internal counter and thus control the PWM waveform frequency, while the other
one is used to control the duty cycle. The PWM waveform frequency and duty cycle can therefore
be controlled by the values in the CCRA and CCRP registers.
An interrupt flag, one for each of the CCRA and CCRP, will be generated when a compare match
occurs from either Comparator A or Comparator P. The PTOC bit in the PTMC1 register is used to
select the required polarity of the PWM waveform while the two PTIO1 and PTIO0 bits are used to
enable the PWM output or to force the TM output pin to a fixed high or low level. The PTPOL bit is
used to reverse the polarity of the PWM output waveform.
• 10-bit PWM Mode, PWM Mode
CCRP
1~1023
0
Period
1~1023
1024
Duty
CCRA
If fSYS=8MHz, TM clock source select fSYS/4, CCRP=512 and CCRA=128,
The PTM PWM output frequency=(fSYS/4) / (2×256)=fSYS/2048=3.90625kHz, duty=128/512=25%,
If the Duty value defined by the CCRA register is equal to or greater than the Period value, then the
PWM output duty is 100%.
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Cost-Effective 8-Bit Flash MCU with EEPROM
Counter Value
PTM [1:0] = 10
Counter cleared by
CCRP
Counter Reset when
PTON returns high
CCRP
Pause
Resume
Counter Stop if
PTON bit low
CCRA
Time
PTON
PTPAU
PTPOL
CCRA Int. Flag
PTMAF
CCRP Int. Flag
PTMPF
PTM O/P Pin
(PTOC=1)
PTM O/P Pin
(PTOC=0)
PWM Duty Cycle
set by CCRA
PWM resumes
operation
Output controlled by
Output Inverts
other pin-shared function
When PTPOL = 1
PWM Period set by CCRP
PWM Output Mode
Note: 1. Here Counter cleared by CCRP
2. A counter clear sets the PWM Period
3. The internal PWM function continues running even when PTIO[1:0]=00 or 01
4. The PTCCLR bit has no influence on PWM operation
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Single Pulse Output Mode
To select this mode, the required bit pairs, PTM1 and PTM0 should be set to 10 respectively and
also the corresponding PTIO1 and PTIO0 bits should be set to 11 respectively. The Single Pulse
Output Mode, as the name suggests, will generate a single shot pulse on the TM output pin.
The trigger for the pulse output leading edge is a low to high transition of the PTON bit, which can
be implemented using the application program. However in the Single Pulse Mode, the PTON bit
can also be made to automatically change from low to high using the external PTCK pin, which will
in turn initiate the Single Pulse output. When the PTON bit transitions to a high level, the counter
will start running and the pulse leading edge will be generated. The PTON bit should remain high
when the pulse is in its active state. The generated pulse trailing edge will be generated when the
PTON bit is cleared to zero, which can be implemented using the application program or when a
compare match occurs from Comparator A.
However a compare match from Comparator A will also automatically clear the PTON bit and thus
generate the Single Pulse output trailing edge. In this way the CCRA value can be used to control the
pulse width. A compare match from Comparator A will also generate TM interrupts. The counter can
only be reset back to zero when the PTON bit changes from low to high when the counter restarts.
In the Single Pulse Mode CCRP is not used. The PTCCLR bit is also not used.
Leading Edge
Trailing Edge
PTON bit
0→1
PTON bit
1→0
S/W Command
SET“PTON”
or
PTCK Pin
Transition
S/W Command
CLR“PTON”
or
CCRA Compare
Match
PTP/PTPB Output Pin
Pulse Width = CCRA Value
Single Pulse Generation
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Counter Value
PTM [1:0] = 10 ; PTIO [1:0] = 11
Counter stopped by
CCRA
Counter Reset when
PTON returns high
CCRA
Pause
Counter Stops
by software
Resume
CCRP
Time
PTON
Software
Trigger
Cleared by
CCRA match
Auto. set by
PTCK pin
PTCK pin
Software
Trigger
Software
Trigger
Software
Software Trigger
Clear
PTCK pin
Trigger
PTPAU
PTPOL
CCRP Int. Flag
PTMPF
No CCRP
Interrupts
generated
CCRA Int. Flag
PTMAF
PTM O/P Pin
(PTOC=1)
PTM O/P Pin
(PTOC=0)
Pulse Width
set by CCRA
Output Inverts
when PTPOL = 1
Single Pulse Mode
Note: 1. Counter stopped by CCRA
2. CCRP is not used
3. The pulse is triggered by the PTCK pin or by setting the PTON bit high
4. A PTCK pin active edge will automatically set the PTON bit high
5. In the Single Pulse Mode, PTIO [1:0] must be set to “11” and can not be changed.
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Capture Input Mode
To select this mode bits PTM1 and PTM0 in the PTMC1 register should be set to 01 respectively.
This mode enables external signals to capture and store the present value of the internal counter
and can therefore be used for applications such as pulse width measurements. The external signal
is supplied on the PTPI or PTCK pin, selected by the PTCKS bit in the PTMC1 register. The input
pin active edge can be either a rising edge, a falling edge or both rising and falling edges; the active
edge transition type is selected using the PTIO1 and PTIO0 bits in the PTMC1 register. The counter
is started when the PTON bit changes from low to high which is initiated using the application
program.
When the required edge transition appears on the PTPI or PTCK pin the present value in the counter
will be latched into the CCRA register and a TM interrupt generated. Irrespective of what events
occur on the PTPI or PTCK pin the counter will continue to free run until the PTON bit changes
from high to low. When a CCRP compare match occurs the counter will reset back to zero; in this
way the CCRP value can be used to control the maximum counter value. When a CCRP compare
match occurs from Comparator P, a TM interrupt will also be generated. Counting the number of
overflow interrupt signals from the CCRP can be a useful method in measuring long pulse widths.
The PTIO1 and PTIO0 bits can select the active trigger edge on the PTPI or PTCK pin to be a rising
edge, falling edge or both edge types. If the PTIO1 and PTIO0 bits are both set high, then no capture
operation will take place irrespective of what happens on the PTPI or PTCK pin, however it must be
noted that the counter will continue to run.
As the PTPI or PTCK pin is pin shared with other functions, care must be taken if the PTM is in the
Capture Input Mode. This is because if the pin is setup as an output, then any transitions on this pin
may cause an input capture operation to be executed. The PTCCLR, PTOC and PTPOL bits are not
used in this Mode.
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Counter Value
PTM [1:0] = 01
Counter cleared b�
CCRP
Counter
Stop
Counter
Reset
CCRP
YY
Resume
Pause
XX
Time
PTON
PTPAU
Active
edge
Active edge
Active
edge
PT� capture pin
PTPI or PTCK
CCRA Int.
Flag PT�AF
CCRP Int.
Flag PT�PF
CCRA
Value
PTIO [1:0]
Value
XX
00 – Rising edge
YY
01 – Falling edge
XX
10 – Both edges
YY
11 – Disable Capture
Capture Input Mode
Note: 1. PTM[1:0]=01 and active edge set by the PTIO[1:0] bits
2. A TM Capture input pin active edge transfers counter value to CCRA
3. The PTCCLR bit is not used
4. No output function – PTOC and PTPOL bits are not used
5. CCRP determines the counter value and the counter has a maximum count value when CCRP is equal to
zero
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Analog to Digital Converter – ADC
The need to interface to real world analog signals is a common requirement for many electronic
systems. However, to properly process these signals by a microcontroller, they must first be
converted into digital signals by A/D converters. By integrating the A/D conversion electronic
circuitry into the microcontroller, the need for external components is reduced significantly with the
corresponding follow-on benefits of lower costs and reduced component space requirements.
A/D Overview
The devices contain a multi-channel analog to digital converter which can directly interface
to external analog signals, such as that from sensors or other control signals and convert these
signals directly into a 12-bit digital value. The external or internal analog signal to be converted
is determined by the SAINS and SACS bit fields. Note that when the internal analog signal is
to be converted, the selected external input channel will automatically be disconnected to avoid
malfunction. More detailed information about the A/D input signal is described in the “A/D
Converter Control Registers” and “A/D Converter Input Signal” sections respectively.
Device
HT66F302/HT66F303
Input Channels
A/D Channel Select Bits
Input Pins
4
SAINS2~SAINS0,
SACS1~SACS0
AN0~AN3
The accompanying block diagram shows the overall internal structure of the A/D converter, together
with its associated registers.
AVDD
fSYS
Pin-shared
selection
SACS1~SACS0
AN0
÷ 2N
(N=0~7)
SACKS2~
SACKS0
ENADC
AVSS
A/D Clock
AN1
ADRFS
SADOL
A/D Converter
A/D Data
Registers
SADOH
AN3
A/D Reference Voltage
START
ADBZ
ENADC
SAINS2~SAINS0
VREFO
SAVRS3~SAVRS0
VREFO
AVDD
AVDD/2
AVDD/4
VBG (1.0V)
VRI OPA
VREFI
(Gain=1~4)
VREFI
ENOPA
AVDD
VR
A/D Converter Structure
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A/D Converter Register Description
Overall operation of the A/D converter is controlled using six registers. A read only register pair
exists to store the ADC data 12-bit value. The remaining four registers are control registers which
setup the operating and control function of the A/D converter.
Bit
Register Name
SADOL(ADRFS=0)
7
6
5
4
3
2
1
0
D3
D2
D1
D0
—
—
—
—
SADOL(ADRFS=1)
D7
D6
D5
D4
D3
D2
D1
D0
SADOH(ADRFS=0)
D11
D10
D9
D8
D7
D6
D5
D4
SADOH(ADRFS=1)
—
—
—
—
D11
D10
D9
D8
SADC0
START
ADBZ
ENADC
ADRFS
—
—
SACS1
SACS0
SADC1
SAINS2
SAINS1
SAINS0
—
—
SACKS2
SACKS1
SACKS0
SADC2
ENOPA
VBGEN
VREFI
VREFO
SAVRS3
SAVRS2
SAVRS1
SAVRS0
PAS7
PAS6
PAS5
PAS4
PAS3
PAS2
PAS1
PAS0
PASR
A/D Converter Register List
A/D Converter Data Registers – SADOL, SADOH
As the devices contain an internal 12-bit A/D converter, it requires two data registers to store the
converted value. These are a high byte register, known as SADOH, and a low byte register, known
as SADOL. After the conversion process takes place, these registers can be directly read by the
microcontroller to obtain the digitised conversion value. As only 12 bits of the 16-bit register space
is utilised, the format in which the data is stored is controlled by the ADRFS bit in the SADC0
register as shown in the accompanying table. D0~D11 are the A/D conversion result data bits. Any
unused bits will be read as zero. Note that the A/D converter data register contents will be cleared to
zero if the A/D converter is disabled.
ADRFS
0
1
SADOH
7
6
5
D11 D10 D9
0
0
0
SADOL
4
3
2
1
0
7
6
5
4
3
2
1
D8
D7
D6
D5
D4
D3
D2
D1
D0
0
0
0
0
D11 D10 D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
0
0
A/D Data Registers
A/D Converter Control Registers – SADC0, SADC1, SADC2, PASR
To control the function and operation of the A/D converter, several control registers known as
SADC0, SADC1 and SADC2 are provided. These 8-bit registers define functions such as the
selection of which analog channel is connected to the internal A/D converter, the digitised data
format, the A/D clock source as well as controlling the start function and monitoring the A/D
converter busy status. As the devices contain only one actual analog to digital converter hardware
circuit, each of the external and internal analog signals must be routed to the converter. The
SACS1~SACS0 bits in the SADC0 register are used to determine which external channel input is
selected to be converted. The SAINS2~SAINS0 bits in the SADC1 register are used to determine
that the analog signal to be converted comes from the internal analog signal or external analog
channel input. If the SAINS2~SAINS0 bits are set to “000” or “100”, the external analog channel
input is selected to be converted and the SACS1~SACS0 bits can determine which external channel
is selected to be converted. If the SAINS2~SAINS0 bits are set to any other values except “000” and
“100”, one of the internal analog signals is selected to be converted. The internal analog signals can
be derived from the A/D converter supply power, AVDD, with a specific ratio of 1, 1/2 or 1/4. If the
internal analog signal is selected to be converted, the external channel signal input will automatically
be switched off to avoid the signal contention.
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Cost-Effective 8-Bit Flash MCU with EEPROM
The pin-shared function control register named PASR, contains the corresponding pin-shared
selection bits which determine which pins on Port A are used as analog inputs for the A/D converter
input and which pins are not to be used as the A/D converter input. When the pin is selected to be an
A/D input, its original function whether it is an I/O or other pin-shared function will be removed. In
addition, any internal pull-high resistors connected to these pins will be automatically removed if the
pin is selected to be an A/D input.
SAINS [2:0]
SACS [1:0]
Input Signals
000, 100
00~11
AN0~AN3
Description
001
xxx
VDD
010
xxx
VDD/2
A/D converter power supply voltage/2
011
xxx
VDD/4
A/D converter power supply voltage/4
External channel analog input
A/D converter power supply voltage
A/D Converter Input Signal Selection
SADC0 Register
Bit
7
6
5
4
3
2
1
0
Name
START
ADBZ
ENADC
R/W
R/W
R
R/W
ADRFS
─
─
SACS1
SACS0
R/W
─
─
R/W
POR
0
0
0
R/W
0
─
─
0
0
Bit 7START: Start the A/D conversion
0 → 1 → 0: Start A/D conversion
0 → 1: Reset the A/D converter and set ADBZ to 0
1 → 0: Start A/D conversion and set ADBZ to 1
This bit is used to initiate an A/D conversion process. The bit is normally low but if set
high and then cleared low again, the A/D converter will initiate a conversion process.
Bit 6ADBZ: A/D Converter busy flag
0: No A/D conversion is in progress
1: A/D conversion is in progress
This read only flag is used to indicate whether the A/D conversion is in progress or
not. When the START bit is set from low to high and then to low again, the ADBZ flag
will be set high to indicate that the A/D conversion is initiated. The ADBZ flag will be
cleared to zero after the A/D conversion is complete.
Bit 5ENADC: A/D Converter function enable control
0: Disable
1: Enable
This bit controls the A/D internal function. This bit should be set high to enable the A/
D converter. If the bit is set low, then the A/D converter will be switched off reducing
the device power consumption. When the A/D converter function is disabled, the
contents of the A/D data register pair, SADOH and SADOL, will be cleared to zero.
Bit 4ADRFS: A/D Converter data format control
0: ADC output data format → SADOH=D[11:4]; SADOL=D[3:0]
1: ADC output data format → SADOH=D[11:8]; SADOL=D[7:0]
This bit controls the format of the 12-bit converted A/D value in the two A/D data
registers. Details are provided in the A/D converter data register section.
Bit 3~2
Unimplemented, read as “0”
Bit 1~0SACS1~SACS0: A/D converter external analog input channel selection
00: AN0
01: AN1
10: AN2
11: AN3
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Cost-Effective 8-Bit Flash MCU with EEPROM
SADC1 Register
Bit
7
6
5
4
3
2
1
0
Name
SAINS2
SAINS1
SAINS0
─
─
SACKS2
SACKS1
SACKS0
R/W
R/W
R/W
R/W
─
─
R/W
R/W
R/W
POR
0
0
0
─
─
0
0
0
Bit 7~5SAINS2~SAINS0: A/D converter input signal selection
000, 100: External signal – External analog channel input
001: Internal signal – Internal A/D converter power supply voltage AVDD
010: Internal signal – Internal A/D converter power supply voltage AVDD/2
011: Internal signal – Internal A/D converter power supply voltage AVDD/4
101, 110, 111: Reserved
When the internal analog signal is selected to be converted, the external channel input
signal will automatically be switched off regardless of the SACS1~SACS0 bit field
value.
Bit 4~3
Unimplemented, read as “0”
Bit 2~0SACKS2~SACKS0: A/D conversion clock source selection
000: fSYS
001: fSYS/2
010: fSYS/4
011: fSYS/8
100: fSYS/16
101: fSYS/32
110: fSYS/64
111: fSYS/128
SADC2 Register
Bit
7
6
5
4
3
2
1
0
Name
ENOPA
VBGEN
VREFI
VREFO
SAVRS3
SAVRS2
SAVRS1
SAVRS0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7ENOPA: A/D converter OPA enable/disable control
0: Disable
1: Enable
This bit controls the internal OPA function to provide various reference voltage for
the A/D converter. When the bit is set high, the internal reference voltage, VR, can be
used as the internal converter signal or reference voltage by the A/D converter. If the
internal reference voltage is not used by the A/D converter, then the OPA function
should be properly configured to conserve power.
Bit 6VBGEN: Internal Bandgap reference voltage enable control
0: Disable
1: Enable
This is controls the internal Bandgap circuit on/off function to the A/D converter.
When the bit is set high, the Bandgap reference voltage can be used by the A/D
converter. If the Bandgap reference voltage is not used by the A/D converter and the
LVR function is disabled, then the bandgap reference circuit will be automatically
switched off to conserve power. When the Bandgap reference voltage is switched on
for use by the A/D converter, a time, tBGS, should be allowed for the Bandgap circuit to
stabilise before implementing an A/D conversion.
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Cost-Effective 8-Bit Flash MCU with EEPROM
Bit 5VREFI: VREFI input control
0: Disable
1: Enable
Bit 4VREFO: VREFO output control
0: Disable
1: Enable
Bit 3~0SAVRS3~SAVRS0: A/D converter reference voltage selection
0000: AVDD
0001: VREFI
0010: VREFI × 2
0011: VREFI × 3
0100: VREFI × 4
1001: Inhibit to use
1010: VBG × 2
1011: VBG × 3
1100: VBG × 4
Others: AVDD
When the A/D converter reference voltage source is selected to derive from the
internal VBG voltage, the reference voltage which comes from the AVDD or VREFI pin
will be automatically switched off.
A/D Operation
The START bit is used to start and reset the A/D converter. When the microcontroller sets this bit
from low to high and then low again, an analog to digital conversion cycle will be initiated. When
the START bit is brought from low to high but not low again, the ADBZ bit in the SADC0 register
will be cleared to zero and the analog to digital converter will be reset. It is the START bit that is
used to control the overall start operation of the internal analog to digital converter.
The ADBZ bit in the SADC0 register is used to indicate whether the analog to digital conversion
process is in process or not. When the A/D converter is reset by setting the START bit from low
to high, the ADBZ flag will be cleared to “0”. This bit will be automatically set to “1” by the
microcontroller after an A/D conversion is successfully initiated. When the A/D conversion is
complete, the ADBZ will be cleared to “0”. In addition, the corresponding A/D interrupt request flag
will be set in the interrupt control register, and if the interrupts are enabled, an appropriate internal
interrupt signal will be generated. This A/D internal interrupt signal will direct the program flow to
the associated A/D internal interrupt address for processing. If the A/D internal interrupt is disabled,
the microcontroller can be used to poll the ADBZ bit in the SADC0 register to check whether it has
been cleared as an alternative method of detecting the end of an A/D conversion cycle.
The clock source for the A/D converter, which originates from the system clock fSYS, can be chosen
to be either fSYS or a subdivided version of fSYS. The division ratio value is determined by the
SACKS2~SACKS0 bits in the SADC1 register. Although the A/D clock source is determined by
the system clock fSYS, and by bits SACKS2~SACKS0, there are some limitations on the maximum
A/D clock source speed that can be selected. As the recommended value of permissible A/D clock
period, tADCK, is from 0.5μs to 10μs, care must be taken for system clock frequencies. For example,
if the system clock operates at a frequency of 4MHz, the SACKS2~SACKS0 bits should not be set
to “000”, “110” or “111”. Doing so will give A/D clock periods that are less than the minimum A/D
clock period or greater than the maximum A/D clock period which may result in inaccurate A/D
conversion values. Refer to the following table for examples, where values marked with an asterisk
* show where, depending upon the device, special care must be taken.
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Cost-Effective 8-Bit Flash MCU with EEPROM
A/D Clock Period (tADCK)
fSYS
SACKS2,
SACKS1,
SACKS0
=000
(fSYS)
SACKS2,
SACKS1,
SACKS0
=001
(fSYS/2)
SACKS2,
SACKS1,
SACKS0
=010
(fSYS/4)
SACKS2,
SACKS1,
SACKS0
=011
(fSYS/8)
SACKS2,
SACKS1,
SACKS0
=100
(fSYS/16)
SACKS2,
SACKS1,
SACKS0
=101
(fSYS/32)
SACKS2,
SACKS1,
SACKS0
=110
(fSYS/64)
SACKS2,
SACKS1,
SACKS0
=111
(fSYS/128)
1MHz
1μs
2μs
4μs
8μs
16μs*
32μs*
64μs*
128μs*
2MHz
500ns
1μs
2μs
4μs
8μs
16μs*
32μs*
64μs*
4MHz
250ns*
500ns
1μs
2μs
4μs
8μs
16μs*
32μs*
8MHz
125ns*
250ns*
500ns
1μs
2μs
4μs
8μs
16μs*
A/D Clock Period Examples
Controlling the power on/off function of the A/D converter circuitry is implemented using the
ENADC bit in the SADC0 register. This bit must be set high to power on the A/D converter. When
the ENADC bit is set high to power on the A/D converter internal circuitry a certain delay, as
indicated in the timing diagram, must be allowed before an A/D conversion is initiated. Even if
no pins are selected for use as A/D inputs by configuring the corresponding pin control bits, if the
ENADC bit is high then some power will still be consumed. In power conscious applications it is
therefore recommended that the ENADC is set low to reduce power consumption when the A/D
converter function is not being used.
A/D Reference Voltage
The reference voltage supply to the A/D Converter can be supplied from the positive power supply
pin, AVDD, an external reference source supplied on pin VREFI or an internal reference source
derived from the Bandgap circuit. Then the selected reference voltage source can be amplified
through an operational amplifier except the one sourced from AVDD. The OPA gain can be equal to
1, 2, 3 or 4. The desired selection is made using the SAVRS3~SAVRS0 bits in the SADC2 register
and relevant pin function control bits. Note that the desired selected reference voltage will be output
on the VREFO pin which is pin-shared with other functions. As the VREFI and VREFO pins both
are pin-shared with other functions, when the VREFI or VREFO pin is selected as the reference
voltage supply pin, the pin function control bit VREFI or VREFO should be set high to disable other
pin-shared functions. When VREFI or VBG is selected by ADC reference voltage, the OPA needs to
be enabled by setting the ENOPA bit to “1”. In addition, if the programs select external reference
voltage VREFI and the internal reference voltage VBG as ADC reference voltage, then the hardware
will only choose the internal reference voltage VBG as an ADC reference voltage input.
SAVRS[3:0]
Reference
0000/others
AVDD
ADC Reference Voltage comes from AVDD
Description
0001
VREF
ADC Reference Voltage comes from External VREFI
0010
VREF×2
ADC Reference Voltage comes from External VREFI×2
0011
VREF×3
ADC Reference Voltage comes from External VREFI×3
0100
VREF×4
ADC Reference Voltage comes from External VREFI×4
1010
VBG×2
ADC Reference Voltage comes from VBG×2
1011
VBG×3
ADC Reference Voltage comes from VBG×3
1100
VBG×4
ADC Reference Voltage comes from VBG×4
A/D Converter Reference Voltage Selection
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A/D Converter Input Signal
All of the A/D analog input pins are pin-shared with the I/O pins on Port A as well as other functions.
The corredponding selection bits for each I/O pin in the PASR register, determine whether the input
pins are setup as A/D converter analog inputs or whether they have other functions. If the pin-shared
function control bits configure its corresponding pin as an A/D analog channel input, the pin will
be setup to be an A/D converter external channel input and the original pin functions disabled. In
this way, pins can be changed under program control to change their function between A/D inputs
and other functions. All pull-high resistors, which are setup through register programming, will be
automatically disconnected if the pins are setup as A/D inputs. Note that it is not necessary to first
setup the A/D pin as an input in the PAC port control register to enable the A/D input as when the
pin-shared function control bits enable an A/D input, the status of the port control register will be
overridden.
The A/D converter has its own reference voltage pin, VREFI. However the reference voltage can
also be supplied from the power supply pin or an internal Bandgap circuit, a choice which is made
through the SAVRS3~SAVRS0 bits in the SADC2 register. The selected A/D reference voltage can
be output on the VREFO pin. The analog input values must not be allowed to exceed the value of
VREFI.
Conversion Rate and Timing Diagram
A complete A/D conversion contains two parts, data sampling and data conversion. The data
sampling which is defined as tADS takes 4 A/D clock cycles and the data conversion takes 12 A/D
clock cycles. Therefore a total of 16 A/D clock cycles for an A/D conversion which is defined as tADC
are necessary.
Maximum single A/D conversion rate=A/D clock period /16
The accompanying diagram shows graphically the various stages involved in an analog to digital
conversion process and its associated timing. After an A/D conversion process has been initiated
by the application program, the microcontroller internal hardware will begin to carry out the
conversion, during which time the program can continue with other functions. The time taken for the
A/D conversion is 16tADCK clock cycles where tADCK is equal to the A/D clock period.
tON2ST
ENADC
off
on
off
A/D sampling time
tADS
A/D sampling time
tADS
Start of A/D conversion
Start of A/D conversion
on
START
ADBZ
SACS[1:0]
End of A/D
conversion
11B
A/D channel
switch
End of A/D
conversion
10B
tADC
A/D conversion time
Start of A/D conversion
00B
tADC
A/D conversion time
01B
tADC
A/D conversion time
A/D Conversion Timing
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Summary of A/D Conversion Steps
The following summarises the individual steps that should be executed in order to implement an A/D
conversion process.
• Step 1
Select the required A/D conversion clock by properly programming the SACKS2~SACKS0 bits
in the SADC1 register.
• Step 2
Enable the A/D converter by setting the ENADC bit in the SADC0 register to “1”.
• Step 3
Select which signal is to be connected to the internal A/D converter by correctly configuring the
SAINS2~SAINS0 bits.
Select the external channel input to be converted, go to Step 4.
Select the internal analog signal to be converted, go to Step 5.
• Step 4
If the A/D input signal comes from the external channel input selecting by configuring the SAINS
bit field, the corresponding pin should first be configured as A/D input function by configuring
pin-shared function control bits in the PASR register. The desired analog channel then should be
selected by configuring the SACS bit field. After this step, go to Step 6.
• Step 5
Before the A/D input signal is selected to come from the internal analog signal by configuring
the SAINS bit field, the relevant control bit must be first cleared to zero to disable the external
channel input. The desired internal analog signal then can be selected by configuring the SAINS
bit field. After this step, go to Step 6.
• Step 6
Select the reference voltage source by configuring the SAVRS3~SAVRS0 bits.
Note: If select VREFI as reference voltage, the VREFI bit must be set high.
• Step 7
Select A/D converter output data format by configuring the ADRFS bit.
• Step 8
If A/D conversion interrupt is used, the interrupt control registers must be correctly configured
to ensure the A/D interrupt function is active. The master interrupt control bit, EMI, and the A/D
converter interrupt bits, ADE, must both set high in advance.
• Step 9
The A/D conversion procedure can now be initialised by setting the START bit from low to high
and then low again.
• Step 10
If A/D conversion is in progress, the ADBZ flag will be set high. After the A/D conversion
process is completed, the ADBZ flag will go low and then output data can be read from the
SADOH and SADOL registers. If the ADC interrupt is enabled and the stack is not full, data can
be acquired by interrupt service program.
Note: When checking for the end of the conversion process, if the method of polling the ADBZ bit
in the SADC0 register is used, the interrupt enable step above can be omitted.
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Programming Considerations
During microcontroller operations where the A/D converter is not being used, the A/D internal
circuitry can be switched off to reduce power consumption, by clearing the ENADC bit in the
SADC0 register. When this happens, the internal A/D converter circuits will not consume power
irrespective of what analog voltage is applied to their input lines. If the A/D converter input lines are
used as normal I/Os, then care must be taken as if the input voltage is not at a valid logic level, then
this may lead to some increase in power consumption.
A/D Transfer Function
As the devices contain a 12-bit A/D converter, its full-scale converted digitised value is equal to
FFFH. Since the full-scale analog input value is equal to the actual A/D converter reference voltage,
VREFO, this gives a single bit analog input value of VREFO divided by 4096.
1 LSB=VREFO / 4096
The A/D Converter input voltage value can be calculated using the following equation:
A/D input voltage=A/D output digital value ×VREFO / 4096
The diagram shows the ideal transfer function between the analog input value and the digitised
output value for the A/D converter. Except for the digitised zero value, the subsequent digitised
values will change at a point 0.5 LSB below where they would change without the offset, and the
last full scale digitised value will change at a point 1.5 LSB below the VREFO level. Note that here the
VREFO voltage is the actual A/D converter reference voltage determined by the SAVRS field.
    
­
 
      Ideal A/D Transfer Function
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Cost-Effective 8-Bit Flash MCU with EEPROM
A/D Programming Examples
The following two programming examples illustrate how to setup and implement an A/D conversion.
In the first example, the method of polling the ADBZ bit in the SADC0 register is used to detect
when the conversion cycle is complete, whereas in the second example, the A/D interrupt is used to
determine when the conversion is complete.
Example: using an ADBZ polling method to detect the end of conversion
clr
ADE;
mova,03H
mov SADC1,a ;
set ENADC
mov a,01h ;
mov PASR,a
mova,20h
mov SADC0,a ;
:
start_conversion:
clr START ;
set START ;
clr START ;
polling_EOC:
sz ADBZ ;
jmp polling_EOC ;
mov a,SADOL ;
mov SADOL_buffer,a ;
mov a,SADOH ;
mov SADOH_buffer,a ;
:
jmp start_conversion ;
Rev. 1.00
disable ADC interrupt
select fSYS/8 as A/D clock
setup PASR to configure pin AN0
enable and connect AN0 channel to A/D converter
high pulse on start bit to initiate conversion
reset A/D
start A/D
poll the SADC0 register ADBZ bit to detect end of A/D conversion
continue polling
read low byte conversion result value
save result to user defined register
read high byte conversion result value
save result to user defined register
start next A/D conversion
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Example: using the interrupt method to detect the end of conversion
clr
ADE ;
mova,03H
mov SADC1,a ;
set ENADC
mov a,01h ;
mov PASR,a
mova,20h
mov SADC0,a ;
Start_conversion:
clr START ;
set START ;
clr START ;
clr ADF ;
set
ADE;
set EMI ;
:
:
;
ADC_ISR:
mov acc_stack,a ;
mov a,STATUS
mov status_stack,a ;
:
:
mov a,SADOL ;
mov SADOL_buffer,a ;
mov a,SADOH ;
mov SADOH_buffer,a ;
:
:
EXIT_INT_ISR:
mov a,status_stack
mov STATUS,a ;
mov a,acc_stack ;
reti
Rev. 1.00
disable ADC interrupt
select fSYS/8 as A/D clock
setup PASR to configure pin AN0
enable and connect AN0 channel to A/D converter
high pulse on START bit to initiate conversion
reset A/D
start A/D
clear ADC interrupt request flag
enable ADC interrupt
enable global interrupt
ADC interrupt service routine
save ACC to user defined memory
save STATUS to user defined memory
read
save
read
save
low byte conversion result value
result to user defined register
high byte conversion result value
result to user defined register
restore STATUS from user defined memory
restore ACC from user defined memory
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Interrupts
Interrupts are an important part of any microcontroller system. When an external event or an
internal function such as a Timer Module or an A/D converter requires microcontroller attention,
their corresponding interrupt will enforce a temporary suspension of the main program allowing the
microcontroller to direct attention to their respective needs. The devices contain several external
interrupt and internal interrupts functions. The external interrupt is generated by the action of the
external INT pin, while the internal interrupts are generated by various internal functions such as the
TMs, Time Base, EEPROM and the A/D converter.
Interrupt Registers
Overall interrupt control, which basically means the setting of request flags when certain
microcontroller conditions occur and the setting of interrupt enable bits by the application program,
is controlled by a series of registers, located in the Special Purpose Data Memory, as shown in the
accompanying table. The number of registers depends upon the device chosen but fall into three
categories. The first is the INTC0~INTC1 registers which setup the primary interrupts, the second
is the MFI0~MFI1 registers which setup the Multi-function interrupts. Finally there is an INTEG
register to setup the external interrupt trigger edge type.
Each register contains a number of enable bits to enable or disable individual registers as well as
interrupt flags to indicate the presence of an interrupt request. The naming convention of these
follows a specific pattern. First is listed an abbreviated interrupt type, then the (optional) number of
that interrupt followed by either an “E” for enable/disable bit or “F” for request flag.
Function
Enable Bit
Request Flag
Notes
—
Global
EMI
—
INT Pin
INTE
INTF
—
A/D Converter
ADE
ADF
—
Multi-function
MFnE
MFnF
n=0 or 1
Time Base
TBnE
TBnF
n=0 or 1
EEPROM
DEE
DEF
—
STMAE
STMAF
STMPE
STMPF
PTMAE
PTMAF
PTMPE
PTMPF
TM
—
Interrupt Register Bit Naming Conventions
Bit
Register
Name
7
6
5
4
3
2
1
0
INTEG
—
—
—
—
—
—
INTS1
INTS0
INTC0
—
TB1F
TB0F
INTF
TB1E
TB0E
INTE
EMI
INTC1
MF1F
ADF
DEF
MF0F
MF1E
ADE
DEE
MF0E
MFI0
—
—
STMAF
STMPF
—
—
STMAE
STMPE
MFI1
—
—
PTMAF
PTMPF
—
—
PTMAE
PTMPE
Interrupt Registers List
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Cost-Effective 8-Bit Flash MCU with EEPROM
INTEG Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
—
—
INTS1
INTS0
R/W
—
—
—
—
—
—
R/W
R/W
POR
—
—
—
—
—
—
0
0
Bit 7~2 Unimplemented, read as "0"
Bit 1~0
INTS1, INTS0: interrupt edge control for INT pin
00: Disable Interrupt
01: Rising Edge Interrupt
10: Falling Edge Interrupt
11: Dual Edge Interrupt
INTC0 Register
Bit
7
6
5
4
3
2
1
0
Name
—
TB1F
TB0F
INTF
TB1E
TB0E
INTE
EMI
R/W
—
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
—
0
0
0
0
0
0
0
Bit 7
Unimplemented, read as "0"
Bit 6TB1F : Time Base 1 Interrupt Request Flag
0: No request
1: Interrupt request
Bit 5TB0F: Time Base 0 Interrupt Request Flag
0: No request
1: Interrupt request
Bit 4INTF: INT Interrupt Request Flag
0: No request
1: Interrupt request
Bit 3 TB1E : Time Base 1 Interrupt Control
0: Disable
1: Enable
Bit 2TB0E: Time Base 0 Interrupt Control
0: Disable
1: Enable
Bit 1INTE: INT Interrupt Control
0: Disable
1: Enable
Bit 0EMI: Global Interrupt Control
0: Disable
1: Enable
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Cost-Effective 8-Bit Flash MCU with EEPROM
INTC1 Register
Bit
7
6
5
4
3
2
1
0
Name
MF1F
ADF
DEF
MF0F
MF1E
ADE
DEE
MF0E
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7MF1F: Multi-function 1 Interrupt Request Flag
0: No request
1: Interrupt request
Bit 6ADF: A/D Converter Interrupt Request Flag
0: No request
1: Interrupt request
Bit 5DEF: Data EEPROM Interrupt Request Flag
0: No request
1: Interrupt request
Bit 4MF0F: Multi-function 0 Interrupt Request Flag
0: No request
1: Interrupt request
Bit 3 MF1E: Multi-function 1 Interrupt Control
0: Disable
1: Enable
Bit 2ADE: A/D Converter Interrupt Control
0: Disable
1: Enable
Bit 1DEE: Data EEPROM Interrupt Control
0: Disable
1: Enable
Bit 0MF0E: Multi-function 0 Interrupt Control
0: Disable
1: Enable
MFI0 Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
STMAF
STMPF
—
—
STMAE
STMPE
R/W
—
—
R/W
R/W
—
—
R/W
R/W
POR
—
—
0
0
—
—
0
0
Bit 7~6
Unimplemented, read as "0"
Bit 5STMAF: STM Comparator A match interrupt request flag
0: No request
1: Interrupt request
Bit 4STMPF: STM Comparator P match interrupt request flag
0: No request
1: Interrupt request
Bit 3~2
Unimplemented, read as "0"
Bit 1STMAE: STM Comparator A match interrupt control
0: Disable
1: Enable
Bit 0STMPE: STM Comparator P match interrupt control
0: Disable
1: Enable
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Cost-Effective 8-Bit Flash MCU with EEPROM
MFI1 Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
PTMAF
PTMPF
—
—
PTMAE
PTMPE
R/W
—
—
R/W
R/W
—
—
R/W
R/W
POR
—
—
0
0
—
—
0
0
Bit 7~6
Unimplemented, read as "0"
Bit 5PTMAF: PTM Comparator A match interrupt request flag
0: No request
1: Interrupt request
Bit 4PTMPF: PTM Comparator P match interrupt request flag
0: No request
1: Interrupt request
Bit 3~2
Unimplemented, read as “0”
Bit 1PTMAE: PTM Comparator A match interrupt control
0: Disable
1: Enable
Bit 0PTMPE: PTM Comparator P match interrupt control
0: Disable
1: Enable
Interrupt Operation
When the conditions for an interrupt event occur, such as a TM Comparator P or Comparator A
match or A/D conversion completion etc, the relevant interrupt request flag will be set. Whether
the request flag actually generates a program jump to the relevant interrupt vector is determined by
the condition of the interrupt enable bit. If the enable bit is set high then the program will jump to
its relevant vector; if the enable bit is zero then although the interrupt request flag is set an actual
interrupt will not be generated and the program will not jump to the relevant interrupt vector. The
global interrupt enable bit, if cleared to zero, will disable all interrupts.
When an interrupt is generated, the Program Counter, which stores the address of the next instruction
to be executed, will be transferred onto the stack. The Program Counter will then be loaded with a
new address which will be the value of the corresponding interrupt vector. The microcontroller will
then fetch its next instruction from this interrupt vector. The instruction at this vector will usually
be a “JMP” which will jump to another section of program which is known as the interrupt service
routine. Here is located the code to control the appropriate interrupt. The interrupt service routine
must be terminated with a “RETI”, which retrieves the original Program Counter address from
the stack and allows the microcontroller to continue with normal execution at the point where the
interrupt occurred.
The various interrupt enable bits, together with their associated request flags, are shown in the
accompanying diagrams with their order of priority. Some interrupt sources have their own
individual vector while others share the same multi-function interrupt vector. Once an interrupt
subroutine is serviced, all the other interrupts will be blocked, as the global interrupt enable bit,
EMI bit will be cleared automatically. This will prevent any further interrupt nesting from occurring.
However, if other interrupt requests occur during this interval, although the interrupt will not be
immediately serviced, the request flag will still be recorded.
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Cost-Effective 8-Bit Flash MCU with EEPROM
If an interrupt requires immediate servicing while the program is already in another interrupt service
routine, the EMI bit should be set after entering the routine, to allow interrupt nesting. If the stack
is full, the interrupt request will not be acknowledged, even if the related interrupt is enabled, until
the Stack Pointer is decremented. If immediate service is desired, the stack must be prevented from
becoming full. In case of simultaneous requests, the accompanying diagram shows the priority that
is applied. All of the interrupt request flags when set will wake-up the device if it is in SLEEP or
IDLE Mode, however to prevent a wake-up from occurring the corresponding flag should be set
before the device is in SLEEP or IDLE Mode.
E�I auto disabled in ISR
Legend
xxF
Request Flag� no auto reset in ISR
xxF
Request Flag� auto reset in ISR
xxE
Enable Bits
Interrupt
Name
Request
Flags
Enable
Bits
ST� P
ST�PF
ST�PE
ST� A
ST�AF
ST�AE
PT� P
PT�PF
PT�PE
PT� A
PT�AF
PT�AE
Interrupt
Name
Request
Flags
Enable
Bits
�aster
Enable
Vector
INT Pin
INTF
INTE
E�I
04H
Time Base 0
TB0F
TB0E
E�I
08H
Time Base 1
TB1F
TB1E
E�I
0CH
�. Funct. 0
�F0F
�F0E
E�I
10H
EEPRO�
DEF
DEE
E�I
14H
A/D
ADF
ADE
E�I
18H
�. Funct. 1
�F1F
�F1E
E�I
1CH
Priorit�
High
Low
Interrupts contained within
�ulti-Function Interrupts
Interrupt Structure
External Interrupt
The external interrupt is controlled by signal transitions on the INT pin. An external interrupt
request will take place.when the external interrupt request flag, INTF, is set, which will occur when
a transition, whose type is chosen by the edge select bits, appears on the external interrupt pin. To
allow the program to branch to the interrupt vector address, the global interrupt enable bit, EMI, and
the external interrupt enable bit, INTE, must first be set. Additionally the correct interrupt edge type
must be selected using the INTEG register to enable the external interrupt function and to choose the
trigger edge type. As the external interrupt pin is pin-shared with I/O pin, it can only be configured
as an external interrupt pin by setting the pin-shared register PASR. The pin must also be setup as an
input by setting the corresponding bit in the port control register. When the interrupt is enabled, the
stack is not full and the correct transition type appears on the external interrupt pin, a subroutine call
to the external interrupt vector, will take place. When the interrupt is serviced, the external interrupt
request flag, INTF, will be automatically reset and the EMI bit will be automatically cleared to
disable other interrupts. Note that the pull-high resistor selection on the external interrupt pin will
remain valid even if the pin is used as an external interrupt input.
The INTEG register is used to select the type of active edge that will trigger the external interrupt.
A choice of either rising or falling or both edge types can be chosen to trigger an external interrupt.
Note that the INTEG register can also be used to disable the external interrupt function.
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Cost-Effective 8-Bit Flash MCU with EEPROM
Multi-function Interrupt
Within the device there are up to two Multi-function interrupts. Unlike the other independent
interrupts, these interrupts have no independent source, but rather are formed from other existing
interrupt sources, namely the TM Interrupts.
A Multi-function interrupt request will take place when any of the Multi-function interrupt request
flags, MF0F~MF1F are set. The Multi-function interrupt flags will be set when any of their included
functions generate an interrupt request flag. To allow the program to branch to its respective interrupt
vector address, when the Multi-function interrupt is enabled and the stack is not full, and either one
of the interrupts contained within each of Multi-function interrupt occurs, a subroutine call to one of
the Multi-function interrupt vectors will take place. When the interrupt is serviced, the related MultiFunction request flag, will be automatically reset and the EMI bit will be automatically cleared to
disable other interrupts.
However, it must be noted that, although the Multi-function Interrupt flags will be automatically
reset when the interrupt is serviced, the request flags from the original source of the Multi-function
interrupts, namely the TM Interrupts, will not be automatically reset and must be manually reset by
the application program.
A/D Converter Interrupt
The devices contain an A/D converter which has its own independent interrupt. The A/D Converter
Interrupt is controlled by the termination of an A/D conversion process. An A/D Converter Interrupt
request will take place when the A/D Converter Interrupt request flag, ADF, is set, which occurs
when the A/D conversion process finishes. To allow the program to branch to its respective interrupt
vector address, the global interrupt enable bit, EMI, and A/D Interrupt enable bit, ADE, must first be
set. When the interrupt is enabled, the stack is not full and the A/D conversion process has ended, a
subroutine call to the A/D Converter Interrupt vector, will take place. When the interrupt is serviced,
the A/D Converter Interrupt flag, ADF, will be automatically cleared. The EMI bit will also be
automatically cleared to disable other interrupts.
Time Base Interrupts
The function of the Time Base Interrupts is to provide regular time signal in the form of an internal
interrupt. They are controlled by the overflow signals from their respective timer functions. When
these happens their respective interrupt request flags, TB0F or TB1F will be set. To allow the
program to branch to their respective interrupt vector addresses, the global interrupt enable bit, EMI
and Time Base enable bits, TB0E or TB1E, must first be set. When the interrupt is enabled, the stack
is not full and the Time Base overflows, a subroutine call to their respective vector locations will
take place. When the interrupt is serviced, the respective interrupt request flag, TB0F or TB1F, will
be automatically reset and the EMI bit will be cleared to disable other interrupts.
The purpose of the Time Base Interrupt is to provide an interrupt signal at fixed time periods. Their
clock sources originate from the internal clock source fTB. This fTB input clock passes through a
divider, the division ratio of which is selected by programming the appropriate bits in the TBC
register to obtain longer interrupt periods whose value ranges. The clock source that generates fTB,
which in turn controls the Time Base interrupt period, can originate from several different sources,
as shown in the System Operating Mode section.
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Cost-Effective 8-Bit Flash MCU with EEPROM
TBC Register
Bit
7
6
5
4
3
2
1
0
Name
TBON
TBCK
TB11
TB10
—
TB02
TB01
TB00
R/W
R/W
R/W
R/W
R/W
—
R/W
R/W
R/W
POR
0
0
1
1
—
1
1
1
Bit 7TBON: TB0 and TB1 Control bit
0: Disable
1: Enable
Bit 6TBCK: Select fTB Clock
0: fTBC
1: fSYS/4
Bit 5~4TB11~TB10: Select Time Base 1 Time-out Period
00: 4096/fTB
01: 8192/fTB
10: 16384/fTB
11: 32768/fTB
Bit 3
Unimplemented, read as “0”
Bit 2~0TB02~TB00: Select Time Base 0 Time-out Period
000: 256/fTB
001: 512/fTB
010: 1024/fTB
011: 2048/fTB
100: 4096/fTB
101: 8192/fTB
110: 16384/fTB
111: 32768/fTB
 Time Base Interrupt
EEPROM Interrupt
An EEPROM Interrupt request will take place when the EEPROM Interrupt request flag, DEF, is set,
which occurs when an EEPROM Write cycle ends. To allow the program to branch to its respective
interrupt vector address, the global interrupt enable bit, EMI, and EEPROM Interrupt enable bit,
DEE, must first be set. When the interrupt is enabled, the stack is not full and an EEPROM Write
cycle ends, a subroutine call to the respective EEPROM Interrupt vector, will take place. When the
EEPROM Interrupt is serviced, the EMI bit will be automatically cleared to disable other interrupts,
and the EEPROM interrupt request flag, DEF, will also be automatically cleared.
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TM Interrupts
The TMs each has two interrupts. All of the TM interrupts are contained within the Multi-function
Interrupts. For each of the TMs there are two interrupt request flags xTMPF and xTMAF and two
enable bits xTMPE and xTMAE. A TM interrupt request will take place when any of the TM request
flags are set, a situation which occurs when a TM comparator P or comparator A match situation
happens.
To allow the program to branch to its respective interrupt vector address, the global interrupt enable
bit, EMI, and the respective TM Interrupt enable bit, and associated Multi-function interrupt enable
bit, MFnF, must first be set. When the interrupt is enabled, the stack is not full and a TM comparator
match situation occurs, a subroutine call to the relevant TM Interrupt vector locations, will take
place. When the TM interrupt is serviced, the EMI bit will be automatically cleared to disable other
interrupts, however only the related MFnF flag will be automatically cleared. As the TM interrupt
request flags will not be automatically cleared, they have to be cleared by the application program.
Interrupt Wake-up Function
Each of the interrupt functions has the capability of waking up the microcontroller when in the
SLEEP or IDLE Mode. A wake-up is generated when an interrupt request flag changes from low to
high and is independent of whether the interrupt is enabled or not. Therefore, even though the device
is in the SLEEP or IDLE Mode and its system oscillator stopped, situations such as external edge
transitions on the external interrupt pin, a low power supply voltage or comparator input change may
cause their respective interrupt flag to be set high and consequently generate an interrupt. Care must
therefore be taken if spurious wake-up situations are to be avoided. If an interrupt wake-up function
is to be disabled then the corresponding interrupt request flag should be set high before the device
enters the SLEEP or IDLE Mode. The interrupt enable bits have no effect on the interrupt wake-up
function.
Programming Considerations
By disabling the relevant interrupt enable bits, a requested interrupt can be prevented from being
serviced, however, once an interrupt request flag is set, it will remain in this condition in the
interrupt register until the corresponding interrupt is serviced or until the request flag is cleared by
the application program.
Where a certain interrupt is contained within a Multi-function interrupt, then when the interrupt
service routine is executed, as only the Multi-function interrupt request flags, MF0F~MF1F, will
be automatically cleared, the individual request flag for the function needs to be cleared by the
application program.
It is recommended that programs do not use the “CALL” instruction within the interrupt service
subroutine. Interrupts often occur in an unpredictable manner or need to be serviced immediately.
If only one stack is left and the interrupt is not well controlled, the original control sequence will be
damaged once a CALL subroutine is executed in the interrupt subroutine.
Every interrupt has the capability of waking up the microcontroller when it is in SLEEP or IDLE
Mode, the wake up being generated when the interrupt request flag changes from low to high. If it is
required to prevent a certain interrupt from waking up the microcontroller then its respective request
flag should be first set high before enter SLEEP or IDLE Mode.
As only the Program Counter is pushed onto the stack, then when the interrupt is serviced, if the
contents of the accumulator, status register or other registers are altered by the interrupt service
program, their contents should be saved to the memory at the beginning of the interrupt service
routine.
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To return from an interrupt subroutine, either a RET or RETI instruction may be executed. The RETI
instruction in addition to executing a return to the main program also automatically sets the EMI
bit high to allow further interrupts. The RET instruction however only executes a return to the main
program leaving the EMI bit in its present zero state and therefore disabling the execution of further
interrupts.
Configuration Option
Configuration options refer to certain options within the MCU that are programmed into the device
during the programming process. During the development process, these options are selected using
the HT-IDE software development tools. As these options are programmed into the device using
the hardware programming tools, once they are selected they cannot be changed later using the
application program. All options must be defined for proper system function, the details of which are
shown in the table.
No.
Options
Oscillator Options
1
HIRC Frequency Selection:
1. 4MHz
2. 8MHz
Application Circuits
VDD
0.01µF**
1N4148*
VDD
10kΩ~
100kΩ
0.1µF
0.1µF~1µF
300Ω*
Reset
Circuit
RES
AN0~AN3
PA0~PA7
PB0~PB5
(HT66F303 only)
VSS
Note: “*” Recommended component for added ESD protection.
“**” Recommended component in environments where power line noise is significant.
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Instruction Set
Introduction
Central to the successful operation of any microcontroller is its instruction set, which is a set of
program instruction codes that directs the microcontroller to perform certain operations. In the case
of Holtek microcontroller, a comprehensive and flexible set of over 60 instructions is provided to
enable programmers to implement their application with the minimum of programming overheads.
For easier understanding of the various instruction codes, they have been subdivided into several
functional groupings.
Instruction Timing
Most instructions are implemented within one instruction cycle. The exceptions to this are branch,
call, or table read instructions where two instruction cycles are required. One instruction cycle is
equal to 4 system clock cycles, therefore in the case of an 8MHz system oscillator, most instructions
would be implemented within 0.5μs and branch or call instructions would be implemented within
1μs. Although instructions which require one more cycle to implement are generally limited to
the JMP, CALL, RET, RETI and table read instructions, it is important to realize that any other
instructions which involve manipulation of the Program Counter Low register or PCL will also take
one more cycle to implement. As instructions which change the contents of the PCL will imply a
direct jump to that new address, one more cycle will be required. Examples of such instructions
would be “CLR PCL” or “MOV PCL, A”. For the case of skip instructions, it must be noted that if
the result of the comparison involves a skip operation then this will also take one more cycle, if no
skip is involved then only one cycle is required.
Moving and Transferring Data
The transfer of data within the microcontroller program is one of the most frequently used
operations. Making use of several kinds of MOV instructions, data can be transferred from registers
to the Accumulator and vice-versa as well as being able to move specific immediate data directly
into the Accumulator. One of the most important data transfer applications is to receive data from
the input ports and transfer data to the output ports.
Arithmetic Operations
The ability to perform certain arithmetic operations and data manipulation is a necessary feature of
most microcontroller applications. Within the Holtek microcontroller instruction set are a range of
add and subtract instruction mnemonics to enable the necessary arithmetic to be carried out. Care
must be taken to ensure correct handling of carry and borrow data when results exceed 255 for
addition and less than 0 for subtraction. The increment and decrement instructions such as INC,
INCA, DEC and DECA provide a simple means of increasing or decreasing by a value of one of the
values in the destination specified.
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Logical and Rotate Operation
The standard logical operations such as AND, OR, XOR and CPL all have their own instruction
within the Holtek microcontroller instruction set. As with the case of most instructions involving
data manipulation, data must pass through the Accumulator which may involve additional
programming steps. In all logical data operations, the zero flag may be set if the result of the
operation is zero. Another form of logical data manipulation comes from the rotate instructions such
as RR, RL, RRC and RLC which provide a simple means of rotating one bit right or left. Different
rotate instructions exist depending on program requirements. Rotate instructions are useful for serial
port programming applications where data can be rotated from an internal register into the Carry
bit from where it can be examined and the necessary serial bit set high or low. Another application
which rotate data operations are used is to implement multiplication and division calculations.
Branches and Control Transfer
Program branching takes the form of either jumps to specified locations using the JMP instruction
or to a subroutine using the CALL instruction. They differ in the sense that in the case of a
subroutine call, the program must return to the instruction immediately when the subroutine has
been carried out. This is done by placing a return instruction “RET” in the subroutine which will
cause the program to jump back to the address right after the CALL instruction. In the case of a JMP
instruction, the program simply jumps to the desired location. There is no requirement to jump back
to the original jumping off point as in the case of the CALL instruction. One special and extremely
useful set of branch instructions are the conditional branches. Here a decision is first made regarding
the condition of a certain data memory or individual bits. Depending upon the conditions, the
program will continue with the next instruction or skip over it and jump to the following instruction.
These instructions are the key to decision making and branching within the program perhaps
determined by the condition of certain input switches or by the condition of internal data bits.
Bit Operations
The ability to provide single bit operations on Data Memory is an extremely flexible feature of all
Holtek microcontrollers. This feature is especially useful for output port bit programming where
individual bits or port pins can be directly set high or low using either the “SET [m].i” or “CLR [m].i”
instructions respectively. The feature removes the need for programmers to first read the 8-bit output
port, manipulate the input data to ensure that other bits are not changed and then output the port with
the correct new data. This read-modify-write process is taken care of automatically when these bit
operation instructions are used.
Table Read Operations
Data storage is normally implemented by using registers. However, when working with large
amounts of fixed data, the volume involved often makes it inconvenient to store the fixed data in
the Data Memory. To overcome this problem, Holtek microcontrollers allow an area of Program
Memory to be setup as a table where data can be directly stored. A set of easy to use instructions
provides the means by which this fixed data can be referenced and retrieved from the Program
Memory.
Other Operations
In addition to the above functional instructions, a range of other instructions also exist such as
the “HALT” instruction for Power-down operations and instructions to control the operation of
the Watchdog Timer for reliable program operations under extreme electric or electromagnetic
environments. For their relevant operations, refer to the functional related sections.
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Instruction Set Summary
The following table depicts a summary of the instruction set categorised according to function and
can be consulted as a basic instruction reference using the following listed conventions.
Table Conventions
x: Bits immediate data
m: Data Memory address
A: Accumulator
i: 0~7 number of bits
addr: Program memory address
Mnemonic
Description
Cycles
Flag Affected
Add Data Memory to ACC
Add ACC to Data Memory
Add immediate data to ACC
Add Data Memory to ACC with Carry
Add ACC to Data memory with Carry
Subtract immediate data from the ACC
Subtract Data Memory from ACC
Subtract Data Memory from ACC with result in Data Memory
Subtract Data Memory from ACC with Carry
Subtract Data Memory from ACC with Carry, result in Data Memory
Decimal adjust ACC for Addition with result in Data Memory
1
1Note
1
1
1Note
1
1
1Note
1
1Note
1Note
Z, C, AC, OV
Z, C, AC, OV
Z, C, AC, OV
Z, C, AC, OV
Z, C, AC, OV
Z, C, AC, OV
Z, C, AC, OV
Z, C, AC, OV
Z, C, AC, OV
Z, C, AC, OV
C
1
1
1
1Note
1Note
1Note
1
1
1
1Note
1
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Increment Data Memory with result in ACC
Increment Data Memory
Decrement Data Memory with result in ACC
Decrement Data Memory
1
1Note
1
1Note
Z
Z
Z
Z
Rotate Data Memory right with result in ACC
Rotate Data Memory right
Rotate Data Memory right through Carry with result in ACC
Rotate Data Memory right through Carry
Rotate Data Memory left with result in ACC
Rotate Data Memory left
Rotate Data Memory left through Carry with result in ACC
Rotate Data Memory left through Carry
1
1Note
1
1Note
1
1Note
1
1Note
None
None
C
C
None
None
C
C
Arithmetic
ADD A,[m]
ADDM A,[m]
ADD A,x
ADC A,[m]
ADCM A,[m]
SUB A,x
SUB A,[m]
SUBM A,[m]
SBC A,[m]
SBCM A,[m]
DAA [m]
Logic Operation
AND A,[m]
OR A,[m]
XOR A,[m]
ANDM A,[m]
ORM A,[m]
XORM A,[m]
AND A,x
OR A,x
XOR A,x
CPL [m]
CPLA [m]
Logical AND Data Memory to ACC
Logical OR Data Memory to ACC
Logical XOR Data Memory to ACC
Logical AND ACC to Data Memory
Logical OR ACC to Data Memory
Logical XOR ACC to Data Memory
Logical AND immediate Data to ACC
Logical OR immediate Data to ACC
Logical XOR immediate Data to ACC
Complement Data Memory
Complement Data Memory with result in ACC
Increment & Decrement
INCA [m]
INC [m]
DECA [m]
DEC [m]
Rotate
RRA [m]
RR [m]
RRCA [m]
RRC [m]
RLA [m]
RL [m]
RLCA [m]
RLC [m]
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Mnemonic
Description
Cycles
Flag Affected
Move Data Memory to ACC
Move ACC to Data Memory
Move immediate data to ACC
1
1Note
1
None
None
None
Clear bit of Data Memory
Set bit of Data Memory
1Note
1Note
None
None
Jump unconditionally
Skip if Data Memory is zero
Skip if Data Memory is zero with data movement to ACC
Skip if bit i of Data Memory is zero
Skip if bit i of Data Memory is not zero
Skip if increment Data Memory is zero
Skip if decrement Data Memory is zero
Skip if increment Data Memory is zero with result in ACC
Skip if decrement Data Memory is zero with result in ACC
Subroutine call
Return from subroutine
Return from subroutine and load immediate data to ACC
Return from interrupt
2
1Note
1Note
1Note
1Note
1Note
1Note
1Note
1Note
2
2
2
2
None
None
None
None
None
None
None
None
None
None
None
None
None
Read table (specific page) to TBLH and Data Memory
Read table (current page) to TBLH and Data Memory
Read table (last page) to TBLH and Data Memory
2Note
2Note
2Note
None
None
None
No operation
Clear Data Memory
Set Data Memory
Clear Watchdog Timer
Pre-clear Watchdog Timer
Pre-clear Watchdog Timer
Swap nibbles of Data Memory
Swap nibbles of Data Memory with result in ACC
Enter power down mode
1
1Note
1Note
1
1
1
1Note
1
1
None
None
None
TO, PDF
TO, PDF
TO, PDF
None
None
TO, PDF
Data Move
MOV A,[m]
MOV [m],A
MOV A,x
Bit Operation
CLR [m].i
SET [m].i
Branch Operation
JMP addr
SZ [m]
SZA [m]
SZ [m].i
SNZ [m].i
SIZ [m]
SDZ [m]
SIZA [m]
SDZA [m]
CALL addr
RET
RET A,x
RETI
Table Read Operation
TABRD [m]
TABRDC [m]
TABRDL [m]
Miscellaneous
NOP
CLR [m]
SET [m]
CLR WDT
CLR WDT1
CLR WDT2
SWAP [m]
SWAPA [m]
HALT
Note: 1. For skip instructions, if the result of the comparison involves a skip then two cycles are required, if no
skip takes place only one cycle is required.
2. Any instruction which changes the contents of the PCL will also require 2 cycles for execution.
3. For the “CLR WDT1” and “CLR WDT2” instructions the TO and PDF flags may be affected by the
execution status. The TO and PDF flags are cleared after both “CLR WDT1” and “CLR WDT2”
instructions are consecutively executed. Otherwise the TO and PDF flags remain unchanged.
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Instruction Definition
ADC A,[m]
Description
Operation
Affected flag(s)
Add Data Memory to ACC with Carry
The contents of the specified Data Memory, Accumulator and the carry flag are added.
The result is stored in the Accumulator.
ACC ← ACC + [m] + C
OV, Z, AC, C
ADCM A,[m]
Description
Operation
Affected flag(s)
Add ACC to Data Memory with Carry
The contents of the specified Data Memory, Accumulator and the carry flag are added. The result is stored in the specified Data Memory.
[m] ← ACC + [m] + C
OV, Z, AC, C
Add Data Memory to ACC
ADD A,[m]
Description
The contents of the specified Data Memory and the Accumulator are added.
The result is stored in the Accumulator.
Operation
Affected flag(s)
ACC ← ACC + [m]
OV, Z, AC, C
ADD A,x
Description
Operation
Affected flag(s)
Add immediate data to ACC
The contents of the Accumulator and the specified immediate data are added. The result is stored in the Accumulator.
ACC ← ACC + x
OV, Z, AC, C
ADDM A,[m]
Description
Operation
Affected flag(s)
Add ACC to Data Memory
The contents of the specified Data Memory and the Accumulator are added. The result is stored in the specified Data Memory.
[m] ← ACC + [m]
OV, Z, AC, C
AND A,[m]
Description
Operation
Affected flag(s)
Logical AND Data Memory to ACC
Data in the Accumulator and the specified Data Memory perform a bitwise logical AND operation. The result is stored in the Accumulator.
ACC ← ACC ″AND″ [m]
Z
AND A,x
Description
Operation
Affected flag(s)
Logical AND immediate data to ACC
Data in the Accumulator and the specified immediate data perform a bit wise logical AND operation. The result is stored in the Accumulator.
ACC ← ACC ″AND″ x
Z
ANDM A,[m]
Description
Operation
Affected flag(s)
Logical AND ACC to Data Memory
Data in the specified Data Memory and the Accumulator perform a bitwise logical AND
operation. The result is stored in the Data Memory.
[m] ← ACC ″AND″ [m]
Z
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CALL addr
Description
Operation
Affected flag(s)
Subroutine call
Unconditionally calls a subroutine at the specified address. The Program Counter then
increments by 1 to obtain the address of the next instruction which is then pushed onto the
stack. The specified address is then loaded and the program continues execution from this
new address. As this instruction requires an additional operation, it is a two cycle instruction.
Stack ← Program Counter + 1
Program Counter ← addr
None
CLR [m]
Description
Operation
Affected flag(s)
Clear Data Memory
Each bit of the specified Data Memory is cleared to 0.
[m] ← 00H
None
CLR [m].i
Description
Operation
Affected flag(s)
Clear bit of Data Memory
Bit i of the specified Data Memory is cleared to 0.
[m].i ← 0
None
CLR WDT
Description
Operation
Affected flag(s)
Clear Watchdog Timer
The TO, PDF flags and the WDT are all cleared.
WDT cleared
TO ← 0
PDF ← 0
TO, PDF
CLR WDT1
Description
Operation
Affected flag(s)
Pre-clear Watchdog Timer
The TO, PDF flags and the WDT are all cleared. Note that this instruction works in
conjunction with CLR WDT2 and must be executed alternately with CLR WDT2 to have
effect. Repetitively executing this instruction without alternately executing CLR WDT2 will
have no effect.
WDT cleared
TO ← 0
PDF ← 0
TO, PDF
CLR WDT2
Description
Operation
Affected flag(s)
Pre-clear Watchdog Timer
The TO, PDF flags and the WDT are all cleared. Note that this instruction works in conjunction
with CLR WDT1 and must be executed alternately with CLR WDT1 to have effect.
Repetitively executing this instruction without alternately executing CLR WDT1 will have no
effect.
WDT cleared
TO ← 0
PDF ← 0
TO, PDF
CPL [m]
Description
Operation
Affected flag(s)
Complement Data Memory
Each bit of the specified Data Memory is logically complemented (1′s complement). Bits which
previously contained a 1 are changed to 0 and vice versa.
[m] ← [m]
Z
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CPLA [m]
Description
Operation
Affected flag(s)
Complement Data Memory with result in ACC
Each bit of the specified Data Memory is logically complemented (1′s complement). Bits which
previously contained a 1 are changed to 0 and vice versa. The complemented result is stored in
the Accumulator and the contents of the Data Memory remain unchanged.
ACC ← [m]
Z
DAA [m]
Description
Operation
Affected flag(s)
Decimal-Adjust ACC for addition with result in Data Memory
Convert the contents of the Accumulator value to a BCD (Binary Coded Decimal) value
resulting from the previous addition of two BCD variables. If the low nibble is greater than 9
or if AC flag is set, then a value of 6 will be added to the low nibble. Otherwise the low nibble
remains unchanged. If the high nibble is greater than 9 or if the C flag is set, then a value of 6
will be added to the high nibble. Essentially, the decimal conversion is performed by adding
00H, 06H, 60H or 66H depending on the Accumulator and flag conditions. Only the C flag
may be affected by this instruction which indicates that if the original BCD sum is greater than
100, it allows multiple precision decimal addition.
[m] ← ACC + 00H or
[m] ← ACC + 06H or [m] ← ACC + 60H or
[m] ← ACC + 66H
C
DEC [m]
Description
Operation
Affected flag(s)
Decrement Data Memory
Data in the specified Data Memory is decremented by 1.
[m] ← [m] − 1
Z
DECA [m]
Description
Operation
Affected flag(s)
Decrement Data Memory with result in ACC
Data in the specified Data Memory is decremented by 1. The result is stored in the
Accumulator. The contents of the Data Memory remain unchanged.
ACC ← [m] − 1
Z
HALT
Description
Operation
Affected flag(s)
Enter power down mode
This instruction stops the program execution and turns off the system clock. The contents of the Data Memory and registers are retained. The WDT and prescaler are cleared. The power
down flag PDF is set and the WDT time-out flag TO is cleared.
TO ← 0
PDF ← 1
TO, PDF
INC [m]
Description
Operation
Affected flag(s)
Increment Data Memory
Data in the specified Data Memory is incremented by 1.
[m] ← [m] + 1
Z
INCA [m]
Description
Operation
Affected flag(s)
Increment Data Memory with result in ACC
Data in the specified Data Memory is incremented by 1. The result is stored in the Accumulator.
The contents of the Data Memory remain unchanged.
ACC ← [m] + 1
Z
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JMP addr
Description
Operation
Affected flag(s)
Jump unconditionally
The contents of the Program Counter are replaced with the specified address. Program
execution then continues from this new address. As this requires the insertion of a dummy
instruction while the new address is loaded, it is a two cycle instruction.
Program Counter ← addr
None
MOV A,[m]
Description
Operation
Affected flag(s)
Move Data Memory to ACC
The contents of the specified Data Memory are copied to the Accumulator.
ACC ← [m]
None
MOV A,x
Description
Operation
Affected flag(s)
Move immediate data to ACC
The immediate data specified is loaded into the Accumulator.
ACC ← x
None
MOV [m],A
Description
Operation
Affected flag(s)
Move ACC to Data Memory
The contents of the Accumulator are copied to the specified Data Memory.
[m] ← ACC
None
NOP
Description
Operation
Affected flag(s)
No operation
No operation is performed. Execution continues with the next instruction.
No operation
None
OR A,[m]
Description
Operation
Affected flag(s)
Logical OR Data Memory to ACC
Data in the Accumulator and the specified Data Memory perform a bitwise
logical OR operation. The result is stored in the Accumulator.
ACC ← ACC ″OR″ [m]
Z
OR A,x
Description
Operation
Affected flag(s)
Logical OR immediate data to ACC
Data in the Accumulator and the specified immediate data perform a bitwise logical OR operation. The result is stored in the Accumulator.
ACC ← ACC ″OR″ x
Z
ORM A,[m]
Description
Operation
Affected flag(s)
Logical OR ACC to Data Memory
Data in the specified Data Memory and the Accumulator perform a bitwise logical OR operation. The result is stored in the Data Memory.
[m] ← ACC ″OR″ [m]
Z
RET
Description
Operation
Affected flag(s)
Return from subroutine
The Program Counter is restored from the stack. Program execution continues at the restored
address.
Program Counter ← Stack
None
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RET A,x
Description
Operation
Affected flag(s)
Return from subroutine and load immediate data to ACC
The Program Counter is restored from the stack and the Accumulator loaded with the specified immediate data. Program execution continues at the restored address.
Program Counter ← Stack
ACC ← x
None
RETI
Description
Operation
Affected flag(s)
Return from interrupt
The Program Counter is restored from the stack and the interrupts are re-enabled by setting the
EMI bit. EMI is the master interrupt global enable bit. If an interrupt was pending when the RETI instruction is executed, the pending Interrupt routine will be processed before returning to the main program.
Program Counter ← Stack
EMI ← 1
None
RL [m]
Description
Operation
Affected flag(s)
Rotate Data Memory left
The contents of the specified Data Memory are rotated left by 1 bit with bit 7 rotated into bit 0.
[m].(i+1) ← [m].i; (i=0~6)
[m].0 ← [m].7
None
RLA [m]
Description
Operation
Affected flag(s)
Rotate Data Memory left with result in ACC
The contents of the specified Data Memory are rotated left by 1 bit with bit 7 rotated into bit 0.
The rotated result is stored in the Accumulator and the contents of the Data Memory remain
unchanged.
ACC.(i+1) ← [m].i; (i=0~6)
ACC.0 ← [m].7
None
RLC [m]
Description
Operation
Affected flag(s)
Rotate Data Memory left through Carry
The contents of the specified Data Memory and the carry flag are rotated left by 1 bit. Bit 7
replaces the Carry bit and the original carry flag is rotated into bit 0.
[m].(i+1) ← [m].i; (i=0~6)
[m].0 ← C
C ← [m].7
C
RLCA [m]
Description
Operation
Affected flag(s)
Rotate Data Memory left through Carry with result in ACC
Data in the specified Data Memory and the carry flag are rotated left by 1 bit. Bit 7 replaces the
Carry bit and the original carry flag is rotated into the bit 0. The rotated result is stored in the
Accumulator and the contents of the Data Memory remain unchanged.
ACC.(i+1) ← [m].i; (i=0~6)
ACC.0 ← C
C ← [m].7
C
RR [m]
Description
Operation
Affected flag(s)
Rotate Data Memory right
The contents of the specified Data Memory are rotated right by 1 bit with bit 0 rotated into bit 7.
[m].i ← [m].(i+1); (i=0~6)
[m].7 ← [m].0
None
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HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
RRA [m]
Description
Operation
Affected flag(s)
Rotate Data Memory right with result in ACC
Data in the specified Data Memory is rotated right by 1 bit with bit 0 rotated into bit 7. The rotated result is stored in the Accumulator and the contents of the
Data Memory remain unchanged.
ACC.i ← [m].(i+1); (i=0~6)
ACC.7 ← [m].0
None
RRC [m]
Description
Operation
Affected flag(s)
Rotate Data Memory right through Carry
The contents of the specified Data Memory and the carry flag are rotated right by 1 bit. Bit 0
replaces the Carry bit and the original carry flag is rotated into bit 7.
[m].i ← [m].(i+1); (i=0~6)
[m].7 ← C
C ← [m].0
C
RRCA [m]
Description
Operation
Affected flag(s)
Rotate Data Memory right through Carry with result in ACC
Data in the specified Data Memory and the carry flag are rotated right by 1 bit. Bit 0 replaces the Carry bit and the original carry flag is rotated into bit 7. The rotated result is stored in the Accumulator and the contents of the Data Memory remain unchanged.
ACC.i ← [m].(i+1); (i=0~6)
ACC.7 ← C
C ← [m].0
C
SBC A,[m]
Description
Operation
Affected flag(s)
Subtract Data Memory from ACC with Carry
The contents of the specified Data Memory and the complement of the carry flag are
subtracted from the Accumulator. The result is stored in the Accumulator. Note that if the result of subtraction is negative, the C flag will be cleared to 0, otherwise if the result is
positive or zero, the C flag will be set to 1.
ACC ← ACC − [m] − C
OV, Z, AC, C
SBCM A,[m]
Description
Operation
Affected flag(s)
Subtract Data Memory from ACC with Carry and result in Data Memory
The contents of the specified Data Memory and the complement of the carry flag are subtracted from the Accumulator. The result is stored in the Data Memory. Note that if the result of subtraction is negative, the C flag will be cleared to 0, otherwise if the result is positive or zero, the C flag will be set to 1.
[m] ← ACC − [m] − C
OV, Z, AC, C
SDZ [m]
Description
Operation
Affected flag(s)
Skip if decrement Data Memory is 0
The contents of the specified Data Memory are first decremented by 1. If the result is 0 the following instruction is skipped. As this requires the insertion of a dummy instruction while the next instruction is fetched, it is a two cycle instruction. If the result is not 0 the program proceeds with the following instruction.
[m] ← [m] − 1
Skip if [m]=0
None
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Cost-Effective 8-Bit Flash MCU with EEPROM
SDZA [m]
Description
Operation
Affected flag(s)
Skip if decrement Data Memory is zero with result in ACC
The contents of the specified Data Memory are first decremented by 1. If the result is 0, the following instruction is skipped. The result is stored in the Accumulator but the specified Data Memory contents remain unchanged. As this requires the insertion of a dummy
instruction while the next instruction is fetched, it is a two cycle instruction. If the result is not 0,
the program proceeds with the following instruction.
ACC ← [m] − 1
Skip if ACC=0
None
SET [m]
Description
Operation
Affected flag(s)
Set Data Memory
Each bit of the specified Data Memory is set to 1.
[m] ← FFH
None
SET [m].i
Description
Operation
Affected flag(s)
Set bit of Data Memory
Bit i of the specified Data Memory is set to 1.
[m].i ← 1
None
SIZ [m]
Description
Operation
Affected flag(s)
Skip if increment Data Memory is 0
The contents of the specified Data Memory are first incremented by 1. If the result is 0, the
following instruction is skipped. As this requires the insertion of a dummy instruction while the next instruction is fetched, it is a two cycle instruction. If the result is not 0 the program
proceeds with the following instruction.
[m] ← [m] + 1
Skip if [m]=0
None
SIZA [m]
Description
Operation
Affected flag(s)
Skip if increment Data Memory is zero with result in ACC
The contents of the specified Data Memory are first incremented by 1. If the result is 0, the following instruction is skipped. The result is stored in the Accumulator but the specified
Data Memory contents remain unchanged. As this requires the insertion of a dummy
instruction while the next instruction is fetched, it is a two cycle instruction. If the result is not
0 the program proceeds with the following instruction.
ACC ← [m] + 1
Skip if ACC=0
None
SNZ [m].i
Description
Operation
Affected flag(s)
Skip if bit i of Data Memory is not 0
If bit i of the specified Data Memory is not 0, the following instruction is skipped. As this
requires the insertion of a dummy instruction while the next instruction is fetched, it is a two cycle instruction. If the result is 0 the program proceeds with the following instruction.
Skip if [m].i ≠ 0
None
SUB A,[m]
Description
Operation
Affected flag(s)
Subtract Data Memory from ACC
The specified Data Memory is subtracted from the contents of the Accumulator. The result is stored in the Accumulator. Note that if the result of subtraction is negative, the C flag will be cleared to 0, otherwise if the result is positive or zero, the C flag will be set to 1.
ACC ← ACC − [m]
OV, Z, AC, C
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Cost-Effective 8-Bit Flash MCU with EEPROM
SUBM A,[m]
Description
Operation
Affected flag(s)
Subtract Data Memory from ACC with result in Data Memory
The specified Data Memory is subtracted from the contents of the Accumulator. The result is stored in the Data Memory. Note that if the result of subtraction is negative, the C flag will be cleared to 0, otherwise if the result is positive or zero, the C flag will be set to 1.
[m] ← ACC − [m]
OV, Z, AC, C
SUB A,x
Description
Operation
Affected flag(s)
Subtract immediate data from ACC
The immediate data specified by the code is subtracted from the contents of the Accumulator. The result is stored in the Accumulator. Note that if the result of subtraction is negative, the C flag will be cleared to 0, otherwise if the result is positive or zero, the C flag will be set to 1.
ACC ← ACC − x
OV, Z, AC, C
SWAP [m]
Description
Operation
Affected flag(s)
Swap nibbles of Data Memory
The low-order and high-order nibbles of the specified Data Memory are interchanged.
[m].3~[m].0 ↔ [m].7~[m].4
None
SWAPA [m]
Description
Operation
Affected flag(s)
Swap nibbles of Data Memory with result in ACC
The low-order and high-order nibbles of the specified Data Memory are interchanged. The result is stored in the Accumulator. The contents of the Data Memory remain unchanged.
ACC.3~ACC.0 ← [m].7~[m].4
ACC.7~ACC.4 ← [m].3~[m].0
None
SZ [m]
Description
Operation
Affected flag(s)
Skip if Data Memory is 0
If the contents of the specified Data Memory is 0, the following instruction is skipped. As this requires the insertion of a dummy instruction while the next instruction is fetched, it is a two cycle instruction. If the result is not 0 the program proceeds with the following instruction.
Skip if [m]=0
None
SZA [m]
Description
Operation
Affected flag(s)
Skip if Data Memory is 0 with data movement to ACC
The contents of the specified Data Memory are copied to the Accumulator. If the value is zero, the following instruction is skipped. As this requires the insertion of a dummy instruction while the next instruction is fetched, it is a two cycle instruction. If the result is not 0 the program proceeds with the following instruction.
ACC ← [m]
Skip if [m]=0
None
SZ [m].i
Description
Operation
Affected flag(s)
Skip if bit i of Data Memory is 0
If bit i of the specified Data Memory is 0, the following instruction is skipped. As this requires
the insertion of a dummy instruction while the next instruction is fetched, it is a two cycle
instruction. If the result is not 0, the program proceeds with the following instruction.
Skip if [m].i=0
None
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Cost-Effective 8-Bit Flash MCU with EEPROM
TABRD [m]
Description
Operation
Affected flag(s)
Read table (specific page) to TBLH and Data Memory
The low byte of the program code (specific page) addressed by the table pointer pair (TBHP and TBLP) is moved to the specified Data Memory and the high byte moved to TBLH.
[m] ← program code (low byte)
TBLH ← program code (high byte)
None
TABRDC [m]
Description
Operation
Affected flag(s)
Read table (current page) to TBLH and Data Memory
The low byte of the program code (current page) addressed by the table pointer (TBLP) is moved to the specified Data Memory and the high byte moved to TBLH.
[m] ← program code (low byte)
TBLH ← program code (high byte)
None
TABRDL [m]
Description
Operation
Affected flag(s)
Read table (last page) to TBLH and Data Memory
The low byte of the program code (last page) addressed by the table pointer (TBLP) is moved to the specified Data Memory and the high byte moved to TBLH.
[m] ← program code (low byte)
TBLH ← program code (high byte)
None
XOR A,[m]
Description
Operation
Affected flag(s)
Logical XOR Data Memory to ACC
Data in the Accumulator and the specified Data Memory perform a bitwise logical XOR operation. The result is stored in the Accumulator.
ACC ← ACC ″XOR″ [m]
Z
XORM A,[m]
Description
Operation
Affected flag(s)
Logical XOR ACC to Data Memory
Data in the specified Data Memory and the Accumulator perform a bitwise logical XOR operation. The result is stored in the Data Memory.
[m] ← ACC ″XOR″ [m]
Z
XOR A,x
Description
Operation
Affected flag(s)
Logical XOR immediate data to ACC
Data in the Accumulator and the specified immediate data perform a bitwise logical XOR operation. The result is stored in the Accumulator.
ACC ← ACC ″XOR″ x
Z
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Cost-Effective 8-Bit Flash MCU with EEPROM
Package Information
Note that the package information provided here is for consultation purposes only. As this
information may be updated at regular intervals users are reminded to consult the Holtek website for
the latest version of the Package/Carton Information.
Additional supplementary information with regard to packaging is listed below. Click on the relevant
section to be transferred to the relevant website page.
• Package Information (include Outline Dimensions, Product Tape and Reel Specifications)
• The Operation Instruction of Packing Materials
• Carton information
Rev. 1.00
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8-pin SOP (150mil) Outline Dimensions
Symbol
Dimensions in inch
Min.
Nom.
Max.
A
—
0.236 BSC
—
B
—
0.154 BSC
—
0.020
C
0.012
—
C′
—
0.193 BSC
—
D
—
—
0.069
E
—
0.050 BSC
—
F
0.004
—
0.010
G
0.016
—
0.050
H
0.004
—
0.010
α
0°
—
8°
Symbol
Rev. 1.00
Dimensions in mm
Min.
Nom.
Max.
A
—
6.00 BSC
—
B
—
3.90 BSC
—
C
0.31
—
0.51
C′
—
4.90 BSC
—
D
—
—
1.75
E
—
1.27 BSC
—
F
0.10
—
0.25
G
0.40
—
1.27
H
0.10
—
0.25
α
0°
—
8°
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Cost-Effective 8-Bit Flash MCU with EEPROM
10-pin SOP (150mil) Outline Dimensions
Symbol
A
Dimensions in inch
Min.
Nom.
Max.
—
0.236 BSC
—
B
—
0.154 BSC
—
C
0.012
—
0.018
C′
—
0.193 BSC
—
D
—
—
0.069
E
—
0.039 BSC
—
F
0.004
—
0.010
G
0.016
—
0.050
H
0.004
—
0.010
α
0°
—
8°
Symbol
Rev. 1.00
Dimensions in mm
Min.
Nom.
Max.
A
—F
6.00 BSC
—
B
—
3.90 BSC
—
0.45
C
0.30
—
C′
—
4.90 BSC
—
D
—
—
1.75
E
—
1.00 BSC
—
F
0.10
—
0.25
G
0.40
—
1.27
H
0.10
—
0.25
α
0°
—
8°
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Cost-Effective 8-Bit Flash MCU with EEPROM
16-pin NSOP (150mil) Outline Dimensions
Symbol
A
Dimensions in inch
Min.
Nom.
Max.
—
0.236 BSC
—
B
—
0.154 BSC
—
C
0.012
—
0.020
C’
—
0.390 BSC
—
D
—
—
0.069
E
—
0.050 BSC
—
F
0.004
—
0.010
G
0.016
—
0.050
H
0.004
—
0.010
α
0°
—
8°
Symbol
Rev. 1.00
Dimensions in mm
Min.
Nom.
Max.
A
—
6.0 BSC
—
B
—
3.9 BSC
—
0.51
C
0.31
—
C’
—
9.9 BSC
—
D
—
—
1.75
E
—
1.27 BSC
—
F
0.10
—
0.25
G
0.40
—
1.27
H
0.10
—
0.25
α
0°
—
8°
128
May 06, 2016
HT66F302/HT66F303
Cost-Effective 8-Bit Flash MCU with EEPROM
Copyright© 2016 by HOLTEK SEMICONDUCTOR INC.
The information appearing in this Data Sheet is believed to be accurate at the time
of publication. However, Holtek assumes no responsibility arising from the use of
the specifications described. The applications mentioned herein are used solely
for the purpose of illustration and Holtek makes no warranty or representation that
such applications will be suitable without further modification, nor recommends
the use of its products for application that may present a risk to human life due to
malfunction or otherwise. Holtek's products are not authorized for use as critical
components in life support devices or systems. Holtek reserves the right to alter
its products without prior notification. For the most up-to-date information, please
visit our web site at http://www.holtek.com.tw.
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