HT66F0175/HT66F0185

A/D 8-Bit Flash MCU with EEPROM
HT66F0175/HT66F0185
Revision: V1.10
Date: �����������������
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Table of Contents
Features................................................................................................................. 7
CPU Features...............................................................................................................................7
Peripheral Features.......................................................................................................................7
General Description.............................................................................................. 8
Selection Table...................................................................................................... 8
Block Diagram....................................................................................................... 9
Pin Assignment..................................................................................................... 9
Pin Descriptions................................................................................................. 11
Absolute Maximum Ratings............................................................................... 17
D.C. Characteristics............................................................................................ 17
A.C. Characteristics............................................................................................ 19
HIRC Electrical Characteristics......................................................................... 20
A/D Converter Electrical Characteristics.......................................................... 21
LVD/LVR Electrical Characteristics................................................................... 22
Comparator Electrical Characteristics............................................................. 22
Software Controlled LCD Driver Electrical Characteristics............................ 23
Power-on Reset Characteristics........................................................................ 23
System Architecture........................................................................................... 24
Clocking and Pipelining...............................................................................................................24
Program Counter.........................................................................................................................25
Stack...........................................................................................................................................26
Arithmetic and Logic Unit – ALU.................................................................................................26
Flash Program Memory...................................................................................... 27
Structure......................................................................................................................................27
Special Vectors...........................................................................................................................27
Look-up Table..............................................................................................................................28
Table Program Example..............................................................................................................28
In Circuit Programming – ICP.....................................................................................................29
On-Chip Debug Support – OCDS...............................................................................................30
Data Memory....................................................................................................... 31
Structure......................................................................................................................................31
Special Function Register Description............................................................. 33
Indirect Addressing Registers – IAR0, IAR1...............................................................................33
Memory Pointers – MP0, MP1....................................................................................................33
Bank Pointer – BP.......................................................................................................................34
Accumulator – ACC.....................................................................................................................34
Program Counter Low Register – PCL........................................................................................34
Look-up Table Registers – TBLP, TBHP, TBLH...........................................................................34
Status Register – STATUS..........................................................................................................35
Rev. 1.10
2
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
EEPROM Data Memory....................................................................................... 37
EEPROM Data Memory Structure..............................................................................................37
EEPROM Registers....................................................................................................................37
Reading Data from the EEPROM...............................................................................................39
Writing Data to the EEPROM......................................................................................................39
Write Protection...........................................................................................................................39
EEPROM Interrupt......................................................................................................................39
Programming Considerations......................................................................................................40
Oscillator............................................................................................................. 41
Oscillator Overview.....................................................................................................................41
System Clock Configurations......................................................................................................41
External Crystal/Ceramic Oscillator – HXT.................................................................................42
Internal High Speed RC Oscillator – HIRC.................................................................................43
External 32.768 kHz Crystal Oscillator – LXT.............................................................................43
Internal 32kHz Oscillator – LIRC.................................................................................................44
Supplementary Oscillators..........................................................................................................44
Operating Modes and System Clocks.............................................................. 45
System Clocks............................................................................................................................45
System Operation Modes............................................................................................................46
Control Registers........................................................................................................................47
Fast Wake-up..............................................................................................................................49
Operating Mode Switching..........................................................................................................50
Standby Current Considerations.................................................................................................54
Wake-up......................................................................................................................................54
Programming Considerations......................................................................................................55
Watchdog Timer.................................................................................................. 55
Watchdog Timer Clock Source....................................................................................................55
Watchdog Timer Control Register...............................................................................................55
Watchdog Timer Operation.........................................................................................................57
Reset and Initialisation....................................................................................... 58
Reset Functions..........................................................................................................................58
Reset Initial Conditions...............................................................................................................60
Input/Output Ports.............................................................................................. 64
Pull-high Resistors......................................................................................................................65
Port A Wake-up...........................................................................................................................65
I/O Port Control Registers...........................................................................................................66
I/O Port Source Current Control..................................................................................................66
Pin-remapping Functions............................................................................................................68
I/O Pin Structures........................................................................................................................69
Programming Considerations......................................................................................................70
Rev. 1.10
3
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Timer Modules – TM........................................................................................... 71
Introduction.................................................................................................................................71
TM Operation..............................................................................................................................71
TM Clock Source.........................................................................................................................72
TM Interrupts...............................................................................................................................72
TM External Pins.........................................................................................................................72
TM Input/Output Pin Control Register.........................................................................................73
Programming Considerations......................................................................................................75
Compact Type TM – CTM................................................................................... 76
Compact TM Operation...............................................................................................................76
Compact Type TM Register Description.....................................................................................77
Compact Type TM Operation Modes..........................................................................................81
Standard Type TM – STM................................................................................... 87
Standard TM Operation...............................................................................................................87
Standard Type TM Register Description.....................................................................................88
Standard Type TM Operation Modes..........................................................................................92
Periodic Type TM – PTM................................................................................... 102
Periodic TM Operation..............................................................................................................102
Periodic Type TM Register Description.....................................................................................103
Periodic Type TM Operation Modes..........................................................................................108
Analog to Digital Converter............................................................................. 117
A/D Overview............................................................................................................................ 117
A/D Converter Register Description.......................................................................................... 118
A/D Input Pins...........................................................................................................................124
A/D Reference Voltage..............................................................................................................124
A/D Operation...........................................................................................................................124
Conversion Rate and Timing Diagram......................................................................................125
Summary of A/D Conversion Steps...........................................................................................126
Programming Considerations....................................................................................................127
A/D Transfer Function...............................................................................................................127
A/D Programming Examples.....................................................................................................128
Serial Interface Module – SIM.......................................................................... 130
SPI Interface.............................................................................................................................130
SPI Registers............................................................................................................................131
SPI Communication..................................................................................................................134
I2C Interface..............................................................................................................................136
I2C Registers.............................................................................................................................137
I2C Bus Communication............................................................................................................141
I2C Time-out Control..................................................................................................................144
Rev. 1.10
4
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Comparators..................................................................................................... 146
Comparator Operation..............................................................................................................146
Comparator Interrupt.................................................................................................................146
Programming Considerations....................................................................................................146
SCOM/SSEG Function for LCD........................................................................ 148
LCD Operation..........................................................................................................................148
LCD Control Registers..............................................................................................................150
UART Interface.................................................................................................. 155
UART External Pin....................................................................................................................156
UART Data Transfer Scheme...................................................................................................156
UART Status and Control Registers.........................................................................................156
Baud Rate Generator................................................................................................................162
UART Setup and Control..........................................................................................................163
UART Transmitter.....................................................................................................................164
UART Receiver.........................................................................................................................165
Managing Receiver Errors........................................................................................................167
UART Interrupt Structure..........................................................................................................168
UART Power Down and Wake-up.............................................................................................169
Low Voltage Detector – LVD............................................................................ 170
LVD Register.............................................................................................................................170
LVD Operation...........................................................................................................................171
Interrupts........................................................................................................... 172
Interrupt Registers.....................................................................................................................172
Interrupt Operation....................................................................................................................179
External Interrupt.......................................................................................................................181
Comparator Interrupt – HT66F0185..........................................................................................181
Multi-function Interrupt..............................................................................................................181
A/D Converter Interrupt.............................................................................................................182
Time Base Interrupt...................................................................................................................182
Serial Interface Module Interrupt...............................................................................................183
UART Transfer Interrupt – HT66F0185.....................................................................................183
LVD Interrupt.............................................................................................................................184
EEPROM Interrupt....................................................................................................................184
TM Interrupt...............................................................................................................................184
Interrupt Wake-up Function.......................................................................................................185
Programming Considerations....................................................................................................185
Configuration Options...................................................................................... 186
Application Circuits.......................................................................................... 186
Rev. 1.10
5
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Instruction Set................................................................................................... 187
Introduction...............................................................................................................................187
Instruction Timing......................................................................................................................187
Moving and Transferring Data...................................................................................................187
Arithmetic Operations................................................................................................................187
Logical and Rotate Operation...................................................................................................188
Branches and Control Transfer.................................................................................................188
Bit Operations...........................................................................................................................188
Table Read Operations.............................................................................................................188
Other Operations.......................................................................................................................188
Instruction Set Summary................................................................................. 189
Table Conventions.....................................................................................................................189
Instruction Definition........................................................................................ 191
Package Information........................................................................................ 200
20-pin SOP (300mil) Outline Dimensions.................................................................................201
20-pin SSOP (150mil) Outline Dimensions...............................................................................202
24-pin SOP (300mil) Outline Dimensions.................................................................................203
24-pin SSOP (150mil) Outline Dimensions...............................................................................204
28-pin SOP (300mil) Outline Dimensions.................................................................................205
28-pin SSOP (150mil) Outline Dimensions...............................................................................206
Rev. 1.10
6
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Features
CPU Features
• Operating voltage
♦♦ fSYS= 8MHz: 2.2V~5.5V
♦♦ fSYS=12MHz: 2.7V~5.5V
♦♦ fSYS=20MHz: 4.5V~5.5V
• Up to 0.2μs instruction cycle with 20MHz system clock at VDD=5V
• Power down and wake-up functions to reduce power consumption
• Oscillator type
♦♦ External High Speed Crystal – HXT
♦♦ External 32.768kHz Crystal – LXT
♦♦ Internal High Speed RC – HIRC
♦♦ Internal 32kHz RC – LIRC
• Fully integrated internal 8/12/16 MHz oscillator requires no external components
• Multi-mode operation: NORMAL, SLOW, IDLE and SLEEP
• All instructions executed in one to two instruction cycles
• Table read instructions
• 63 powerful instructions
• 8-level subroutine nesting
• Bit manipulation instruction
Peripheral Features
• Program Memory: Up to 4K×16
• Data Memory: Up to 256×8
• EEPROM Memory: Up to 128×8
• Watchdog Timer function
• Up to 26 bidirectional I/O lines
• Two external interrupt lines shared with I/O pins
• Multiple Timer Modules for time measure, input capture, compare match output, PWM output
function or single pulse output function
• Serial Interfaces Module – SIM for SPI or I2C
• Software controlled 6-SCOM/SSEG and 18-SSEG lines LCD driver with 1/3 bias
• Programmable I/O port source current for LED applications
• Dual Time-Base functions for generation of fixed time interrupt signals
• 8-channel 12-bit resolution A/D converter
• One Comparator function – available in HT66F0185
• Fully-duplex Universal Asynchronous Receiver and Transmitter Interface – UART, available in
HT66F0185
• Low voltage reset function
• Low voltage detect function
• Flash program memory can be re-programmed up to 100,000 times
• Flash program memory data retention > 10 years
• EEPROM data memory can be re-programmed up to 1,000,000 times
• EEPROM data memory data retention > 10 years
• Wide range of available package types
Rev. 1.10
7
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
General Description
The series of devices are Flash Memory A/D type 8-bit high performance RISC architecture
microcontroller. Offering users the convenience of Flash Memory multi-programming features,
these devices also include 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, calibratuib data, etc.
Analog features include a multi-channel 12-bit A/D converter and a comparator functions. Multiple
and extremely flexible Timer Modules provide timing, pulse generation and PWM generation
functions. Protective features such as an internal Watchdog Timer, Low Voltage Reset and Low
Voltage Detector coupled with excellent noise immunity and ESD protection ensure that reliable
operation is maintained in hostile electrical environments. A full choice of HXT, LXT, HIRC and
LIRC oscillator functions are provided including a fully integrated system oscillator which requires
no external components for its implementation. The ability to operate and switch dynamically
between a range of operating modes using different clock sources gives users the ability to optimise
microcontroller operation and minimize power consumption.
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 Memory
capacity, I/O count, Timer Module features, SSEG count, LED count, UART and package types. The
following table summarises the main features of each device.
Part No.
Program
Memory
Data
Memory
Data
EEPROM
I/O
External
Interrupt
HT66F0175
2k × 16
128 × 8
64 × 8
22
2
12-bit × 8 10-bit PTM × 2
HT66F0185
4k × 16
256 × 8
128 × 8
26
2
16-bit CTM × 1
12-bit × 8 16-bit STM × 1
10-bit PTM × 1
Part No.
Time
SCOM/
SIM UART CMP
SSEG LED Stack
Base
SSEG
A/D
Timer Module
Package
HT66F0175
2
√
—
—
6
14
22
8
20/24SOP/SSOP
HT66F0185
2
√
√
√
6
18
26
8
24/28SOP/SSOP
Note: As devices exist in more than one package format, the table reflects the situation for the package with
the most pins.
Rev. 1.10
8
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Block Diagram
Flash/EEPROM
Programming Circuitry
EEPROM
Data
Memory
Flash
Program
Memory
Watchdog
Timer
Internal
HIRC/LIRC
Oscillators
Low
Voltage
Detect
Low
Voltage
Reset
RAM Data
Memory
Time
Base
Reset
Circuit
8-bit
RISC
MCU
Core
Interrupt
Controller
External
HXT/LXT
Oscillators
12-bit A/D
Converter
Comparator
I/O
SSEG/
SCOM
Timer
Modules
SIM
(SPI/I2C)
+
UART
─
For HT66F0185
For HT66F0185
Pin Assignment
VSS&AVSS
1
�0
VDD&AVDD
PC0/SSEG17/OSC1
�
19
PB0/I�T0/SSEG16/A�0/XT1
PC1/SSEG18/OSC�
3
18
PB1/I�T1/SSEG15/A�1/XT�
PC�/SDO/SSEG0/SCOM0
PA0/TP0/ICPDA/OCDSDA
�
17
PB�/TCK0/SSEG1�/A��
5
16
PA�/TCK1/SSEG13/A�3
PA1/[SDO]/SCS/SSEG�/SCOM�
6
15
PA5/SSEG10/A��/VREFI
PA�/ICPCK/OCDSCK
7
1�
PA3/[SDI/SDA]/SSEG3/SCOM3
8
13
PA6/SSEG9/A�5/VREF
PA7/TP1/SSEG8/A�6
PB6/[SCK/SCL]/SSEG�/SCOM�
PB5/[SCS]/SSEG5/SCOM5
9
1�
PB3/SSEG7/A�7
10
11
PB�/CLO/SSEG6
HT66F0175/HT66V0175
20 SOP-A/SSOP-A
Rev. 1.10
9
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
VSS&AVSS
1
��
VDD&AVDD
PC0/SSEG17/OSC1
�
�3
PB0/I�T0/SSEG16/A�0/XT1
PC1/SSEG18/OSC�
PC�/SDO/SSEG0/SCOM0
3
��
PB1/I�T1/SSEG15/A�1/XT�
�
�1
PB�/TCK0/SSEG1�/A��
PA0/TP0/ICPDA/OCDSDA
PC3/SDI/SDA/SSEG19
5
�0
PA�/TCK1/SSEG13/A�3
6
19
PC6/[I�T0]/SSEG1�
PC�/SCK/SCL/SSEG1/SCOM1
7
18
PC5/[I�T1]/SSEG11
PA1/[SDO]/SCS/SSEG�/SCOM�
8
17
PA5/SSEG10/A��/VREFI
PA�/ICPCK/OCDSCK
PA3/[SDI/SDA]/SSEG3/SCOM3
9
16
PA6/SSEG9/A�5/VREF
10
15
PA7/TP1/SSEG8/A�6
PB6/[SCK/SCL]/SSEG�/SCOM�
11
1�
PB3/SSEG7/A�7
PB5/[SCS]/SSEG5/SCOM5
1�
13
PB�/CLO/SSEG6
HT66F0175/HT66V0175
24 SOP-A/SSOP-A
VSS&AVSS
1
��
VDD&AVDD
PC0/SSEG19/OSC1
�
�3
PC1/SSEG�0/OSC�
PC�/[SDO]/SSEG0/SCOM0
PA0/TP0/ICPDA/OCDSDA
3
��
PB0/I�T0/SSEG18/A�0/XT1
PB1/I�T1/SSEG17/A�1/XT�
�
�1
PB�/TCK0/SSEG16/A��
5
PA�/TCK1/SSEG15/A�3
PC�/SDI/SDA/SSEG��
�0
6
19
PD�/TX/SSEG13
PC5/SCK/SCL/SSEG1/SCOM1
PA1/[SDO]/SSEG�/SCOM�
7
18
8
17
PA�/ICPCK/OCDSCK
PA3/[SDI/SDA]/CX/SSEG3/SCOM3
9
16
10
PB6/[SCK/SCL]/C+/SSEG�/SCOM�
15
PD1/RX/SSEG1�
PA5/SSEG10/A��/VREFI
PA6/TCK�/SSEG9/A�5/VREF
PA7/TP1/SSEG8/A�6
11
1�
PB3/[TX]/TP�/SSEG7/A�7
PB5/[SCS]/C-/SSEG5/SCOM5
1�
13
PB�/[RX]/CLO/SSEG6
HT66F0185/HT66V0185
24 SOP-A/SSOP-A
VSS&AVSS
1
�8
PC0/SSEG19/OSC1
�
�7
VDD&AVDD
PB0/I�T0/SSEG18/A�0/XT1
PC1/SSEG�0/OSC�
3
�6
PB1/I�T1/SSEG17/A�1/XT�
PC�/[SDO]/SSEG0/SCOM0
PA0/TP0/ICPDA/OCDSDA
�
�5
PB�/TCK0/SSEG16/A��
5
��
PA�/TCK1/SSEG15/A�3
PC3/SDO/SSEG�1
6
�3
PD3/SSEG1�
PC�/SDI/SDA/SSEG��
PC5/SCK/SCL/SSEG1/SCOM1
PC6/SCS/SSEG�3
7
��
8
�1
PD�/TX/SSEG13
PD1/RX/SSEG1�
9
�0
PD0/SSEG11
PA1/[SDO]/SSEG�/SCOM�
10
19
PA5/SSEG10/A��/VREFI
PA�/ICPCK/OCDSCK
PA3/[SDI/SDA]/CX/SSEG3/SCOM3
11
18
1�
17
PA6/TCK�/SSEG9/A�5/VREF
PA7/TP1/SSEG8/A�6
PB6/[SCK/SCL]/C+/SSEG�/SCOM�
13
16
PB3/[TX]/TP�/SSEG7/A�7
PB5/[SCS]/C-/SSEG5/SCOM5
1�
15
PB�/[RX]/CLO/SSEG6
HT66F0185/HT66V0185
28 SOP-A/SSOP-A
Note: 1. If the pin-shared pin functions have multiple outputs simultaneously, its pin names at the right side of the “/”
sign can be used for higher priority.
2. VDD&AVDD means the VDD and AVDD are the double bonding.
3. VSS&AVSS means the VSS and AVSS are the double bonding.
4. The OCDSDA and OCDSCK pins are the OCDS dedicated pins and only available for the HT66V01x5
device which is the OCDS EV chip for the HT66F01x5 device.
Rev. 1.10
10
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Pin Descriptions
With the exception of the power pins, all pins on these devices 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.
HT66F0175
Pad Name
PA0/TP0/ICPDA/
OCDSDA
PA1/[SDO]/SCS/
SSEG2/SCOM2
PA2/ICPCK/
OCDSCK
PA3/[SDI/SDA]/
SSEG3/SCOM3
PA4/TCK1/
SSEG13/AN3
PA5/SSEG10/
AN4/VREFI
Rev. 1.10
Function
OPT
PA0
PAWU
PAPU
I/T
TP0
TMPC
ST
CMOS TM0 input/output
ICPDA
—
ST
CMOS ICP Data/Address pin
OCDSDA
—
ST
CMOS OCDS Data/Address pin, for EV chip only.
PA1
PAWU
PAPU
ST
CMOS
[SDO]
SLCDC0
SIMC0
IFS
—
CMOS SPI data output
SCS
SLCDC0
SIMC0 IFS
ST
CMOS SPI slave select
SSEG2
SLCDC0
SLCDC1
—
SSEG Software controlled LCD segment output
SCOM2
SLCDC0
SLCDC1
—
SCOM Software controlled LCD common output
PA2
PAWU
PAPU
ST
CMOS
CMOS ICP Clock pin
ST
O/T
Description
General purpose I/O. Register enabled pull-up and
CMOS
wake-up.
General purpose I/O. Register enabled pull-up and
wake-up.
General purpose I/O. Register enabled pull-up and
wake-up.
ICPCK
—
ST
OCDSCK
—
ST
—
PA3
PAWU
PAPU
ST
CMOS
[SDI]
SLCDC0
SIMC0
IFS
ST
—
[SDA]
SLCDC0
SIMC0
IFS
ST
NMOS I2C address/data line
SSEG3
SLCDC0
SLCDC1
—
SSEG Software controlled LCD segment output
SCOM3
SLCDC0
SLCDC1
—
SCOM Software controlled LCD common output
PA4
PAWU
PAPU
ST
CMOS
TCK1
TM1C0
ST
—
SSEG13
SLCDC2
—
AN3
ACERL
AN
—
PA5
PAWU
PAPU
ST
CMOS
SSEG10
SLCDC2
—
SSEG Software controlled LCD segment output
AN4
ACERL
AN
—
A/D Converter analog input
VREFI
SADC2
AN
—
A/D Converter PGA voltage input
OCDS Clock pin, for EV chip only.
General purpose I/O. Register enabled pull-up and
wake-up.
SPI data input
General purpose I/O. Register enabled pull-up and
wake-up.
TM1 input
SSEG Software controlled LCD segment output
11
A/D Converter analog input
General purpose I/O. Register enabled pull-up and
wake-up.
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Pad Name
PA6/SSEG9/AN5/
VREF
PA7/TP1/SSEG8/
AN6
Function
OPT
PA6
PAWU
PAPU
ST
General purpose I/O. Register enabled pull-up and
CMOS
wake-up.
SSEG9
SLCDC2
—
SSEG Software controlled LCD segment output
PB4/CLO/SSEG6
PB5/[SCS]/
SSEG5/SCOM5
PB6/[SCK/SCL]/
SSEG4/SCOM4
Description
AN5
ACERL
AN
—
A/D Converter analog input
SADC2
—
AO
A/D Converter reference voltage output
PA7
PAWU
PAPU
ST
CMOS
General purpose I/O. Register enabled pull-up and
wake-up.
TP1
TMPC
ST
CMOS TM1 input/output
SSEG8
SLCDC2
—
SSEG Software controlled LCD segment output
AN6
ACERL
AN
PB0
PBPU
ST
IFS
INTEG
ST
—
A/D Converter analog input
CMOS General purpose I/O. Register enabled pull-up.
—
External Interrupt 0
SLCDC3
—
AN0
ACERL
AN
—
A/D Converter analog input
XT1
CO
LXT
—
LXT oscillator pin
PB1
PBPU
ST
INT1
IFS
INTEG
ST
PB1/INT1/
SSEG15/AN1/XT2 SSEG15
PB3/SSEG7/AN7
O/T
VREF
INT0
PB0/INT0/
SSEG16/AN0/XT1 SSEG16
PB2/TCK0/
SSEG14/AN2
I/T
SSEG Software controlled LCD segment output
CMOS General purpose I/O. Register enabled pull-up.
—
SLCDC3
—
AN1
ACERL
AN
—
XT2
CO
—
LXT
PB2
PBPU
ST
TCK0
TM0C0
ST
SSEG14
SLCDC3
—
AN2
ACERL
AN
External Interrupt 1
SSEG Software controlled LCD segment output
A/D Converter analog input
LXT oscillator pin
CMOS General purpose I/O. Register enabled pull-up.
—
TM0 input
SSEG Software controlled LCD segment output
—
A/D Converter analog input
PB3
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up.
SSEG7
SLCDC2
—
SSEG Software controlled LCD segment output
AN7
ACERL
AN
PB4
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up.
CMOS System clock output
—
A/D Converter analog input
CLO
TMPC
—
SSEG6
SLCDC2
—
SSEG Software controlled LCD segment output
PB5
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up.
[SCS]
SLCDC0
SIMC0
IFS
—
CMOS SPI slave select
SSEG5
SLCDC1
—
SSEG Software controlled LCD segment output
SCOM5
SLCDC1
—
SCOM Software controlled LCD common output
PB6
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up.
[SCK]
SIMC0
IFS
ST
CMOS SPI serial clock
[SCL]
SIMC0
IFS
ST
NMOS I2C clock line
SSEG4
SLCDC1
—
SSEG Software controlled LCD segment output
SCOM4
SLCDC1
—
SCOM Software controlled LCD common output
PC0/SSEG17/
OSC1
PC0
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
SSEG17
SLCDC3
—
SSEG Software controlled LCD segment output
OSC1
CO
HXT
PC1/SSEG18/
OSC2
PC1
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
SSEG18
SLCDC3
—
SSEG Software controlled LCD segment output
OSC2
CO
—
Rev. 1.10
—
HXT
12
HXT oscillator pin
HXT oscillator pin
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Pad Name
PC2/SDO/SSEG0/
SCOM0
Function
OPT
I/T
PC2
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
SDO
SIMC0
IFS
—
CMOS SPI data output
SSEG0
SLCDC0
SLCDC1
—
SSEG Software controlled LCD segment output
SCOM0
SLCDC0
SLCDC1
—
SCOM Software controlled LCD common output
PC3
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
SDI
SIMC0
IFS
ST
SDA
SIMC0
IFS
ST
SSEG19
SLCDC3
—
SSEG Software controlled LCD segment output
PC4
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
SCK
SIMC0
IFS
ST
CMOS SPI serial clock
SCL
SIMC0
IFS
ST
NMOS I2C clock line
SSEG1
SLCDC0
SLCDC1
—
SSEG Software controlled LCD segment output
SCOM1
SLCDC0
SLCDC1
—
SCOM Software controlled LCD common output
PC5
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
[INT1]
INTEG
IFS
ST
SSEG11
SLCDC2
—
SSEG Software controlled LCD segment output
PC6
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
[INT0]
INTEG
IFS
ST
SSEG12
SLCDC2
—
VDD
—
PWR
—
Positive power supply
AVDD
—
PWR
—
A/D converter positive power supply
VSS
—
PWR
—
Negative power supply, ground.
AVSS
—
PWR
—
A/D converter negative power supply, ground.
PC3/SDI/SDA/
SSEG19
PC4/SCK/SCL/
SSEG1/SCOM1
PC5/[INT1]/
SSEG11
PC6/[INT0]/
SSEG12
VDD&AVDD
VSS&AVSS
O/T
—
Description
SPI data input
NMOS I2C data line
—
—
External Interrupt 1
External Interrupt 0
SSEG Software controlled LCD segment output
Note: I/T: Input type;
O/T: Output type;
OPT: Optional by configuration option (CO) or register option;
CO: Configuration option;
ST: Schmitt Trigger input; AN: Analog input;
CMOS: CMOS output;
NMOS: NMOS output;
AO: Analog output;
SSEG: Software controlled LCD SEG;
SCOM: Software controlled LCD COM;
HXT: High frequency crystal oscillator; LXT: Low frequency crystal oscillator
PWR: Power
* The AVDD pin is internally bonded together with the VDD pin while the AVSS pin is internally bonded
together with the VSS pin.
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.
HT66F0185
Pad Name
PA0/TP0/ICPDA/
OCDSDA
Rev. 1.10
Function
OPT
I/T
O/T
PA0
PAWU
PAPU
ST
CMOS
Description
General purpose I/O. Register enabled pull-up and
wake-up.
TP0
TMPC
ST
CMOS TM0 input/output
ICPDA
—
ST
CMOS ICP Data/Address pin
OCDSDA
—
ST
CMOS OCDS Data/Address pin, for EV chip only.
13
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Pad Name
PA1/[SDO]/SSEG2/
SCOM2
PA2/ICPCK/
OCDSCK
PA3/[SDI/SDA]/CX/
SSEG3/SCOM3
PA4/TCK1/
SSEG15/AN3
PA5/SSEG10/AN4/
VREFI
PA6/TCK2/SSEG9/
AN5/VREF
PA7/TP1/SSEG8/
AN6
PB0/INT0/SSEG18/
AN0/XT1
Rev. 1.10
Function
OPT
PA1
PAWU
PAPU
I/T
O/T
ST
General purpose I/O. Register enabled pull-up and
CMOS
wake-up.
Description
[SDO]
SLCDC0
SIMC0
IFS
—
CMOS SPI data output
SSEG2
SLCDC0
SLCDC1
—
SSEG Software controlled LCD segment output
SCOM2
SLCDC0
SLCDC1
—
SCOM Software controlled LCD common output
PA2
PAWU
PAPU
ST
CMOS
CMOS ICP Clock pin
General purpose I/O. Register enabled pull-up and
wake-up.
ICPCK
—
ST
OCDSCK
—
ST
—
PA3
PAWU
PAPU
ST
CMOS
[SDI]
SLCDC0
SIMC0
IFS
ST
—
[SDA]
SLCDC0
SIMC0
IFS
ST
NMOS I2C address/data line
CX
CPC
—
CMOS Comparator output
SSEG3
SLCDC0
SLCDC1
—
SSEG Software controlled LCD segment output
SCOM3
SLCDC0
SLCDC1
—
SCOM Software controlled LCD common output
PA4
PAWU
PAPU
ST
CMOS
—
OCDS Clock pin, for EV chip only.
General purpose I/O. Register enabled pull-up and
wake-up.
SPI data input
General purpose I/O. Register enabled pull-up and
wake-up.
TCK1
TM1C0
ST
SSEG15
SLCDC3
—
TM1 input
AN3
ACERL
AN
—
PA5
PAWU
PAPU
ST
CMOS
SSEG10
SLCDC2
—
SSEG Software controlled LCD segment output
SSEG Software controlled LCD segment output
A/D Converter analog input
General purpose I/O. Register enabled pull-up and
wake-up.
AN4
ACERL
AN
—
A/D Converter analog input
VREFI
SADC2
AN
—
A/D Converter PGA voltage input
PA6
PAWU
PAPU
ST
CMOS
—
General purpose I/O. Register enabled pull-up and
wake-up.
TCK2
TM2C0
ST
SSEG9
SLCDC2
—
TM2 input
AN5
ACERL
AN
—
A/D Converter analog input
VREF
SADC2
—
AO
A/D Converter reference voltage output
PA7
PAWU
PAPU
ST
CMOS
SSEG Software controlled LCD segment output
General purpose I/O. Register enabled pull-up and
wake-up.
TP1
TMPC
ST
CMOS TM1 input/output
SSEG8
SLCDC2
—
SSEG Software controlled LCD segment output
AN6
ACERL
AN
PB0
PBPU
ST
INT0
INTEG
IFS
ST
SSEG18
SLCDC3
—
AN0
ACERL
AN
—
A/D Converter analog input
XT1
CO
LXT
—
LXT oscillator pin
—
A/D Converter analog input
CMOS General purpose I/O. Register enabled pull-up.
—
External Interrupt 0
SSEG Software controlled LCD segment output
14
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Pad Name
PB1/INT1/SSEG17/
AN1/XT2
PB2/TCK0/
SSEG16/AN2
PB3/[TX]/TP2/
SSEG7/AN7
PB4/[RX]/CLO/
SSEG6
PB5/[SCS]/C-/
SSEG5/SCOM5
PB6/[SCK/SCL]/C+/
SSEG4/SCOM4
PC0/SSEG19/
OSC1
PC1/SSEG20/
OSC2
PC2/[SDO]/SSEG0/
SCOM0
Rev. 1.10
Function
OPT
I/T
PB1
PBPU
ST
O/T
INT1
INTEG
IFS
ST
SSEG17
SLCDC3
—
AN1
ACERL
AN
—
XT2
CO
—
LXT
PB2
PBPU
ST
Description
CMOS General purpose I/O. Register enabled pull-up.
—
External Interrupt 1
SSEG Software controlled LCD segment output
A/D Converter analog input
LXT oscillator pin
CMOS General purpose I/O. Register enabled pull-up.
TCK0
TM0C0
ST
SSEG16
SLCDC3
—
—
TM0 input
AN2
ACERL
AN
PB3
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up.
[TX]
UCR1
UCR2
—
CMOS UART TX serial data output
SSEG Software controlled LCD segment output
—
A/D Converter analog input
TP2
TMPC
ST
CMOS TM2 input/output
SSEG7
SLCDC2
—
SSEG Software controlled LCD segment output
AN7
ACERL
AN
PB4
PBPU
ST
[RX]
UCR1
UCR2
ST
—
A/D Converter analog input
CMOS General purpose I/O. Register enabled pull-up.
—
UART RX serial data input
CLO
TMPC
—
SSEG6
SLCDC2
—
CMOS System clock output
SSEG Software controlled LCD segment output
PB5
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up.
[SCS]
SLCDC0
SIMC0
IFS
ST
CMOS SPI slave select
C-
CPC
AN
—
Comparator input
SSEG5
SLCDC1
—
SSEG Software controlled LCD segment output
SCOM5
SLCDC1
—
SCOM Software controlled LCD common output
PB6
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up.
[SCK]
SIMC0
IFS
ST
CMOS SPI serial clock
[SCL]
SIMC0
IFS
ST
NMOS I2C clock line
C+
CPC
AN
SSEG4
SLCDC1
—
SSEG Software controlled LCD segment output
SCOM4
SLCDC1
—
SCOM Software controlled LCD common output
PC0
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
SSEG19
SLCDC3
—
SSEG Software controlled LCD segment output
OSC1
CO
HXT
PC1
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
SSEG20
SLCDC3
—
SSEG Software controlled LCD segment output
—
—
HXT
Comparator input
HXT oscillator pin
OSC2
CO
—
PC2
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
[SDO]
SIMC0
IFS
—
CMOS SPI data output
SSEG0
SLCDC0
SLCDC1
—
SSEG Software controlled LCD segment output
SCOM0
SLCDC0
SLCDC1
—
SCOM Software controlled LCD common output
15
HXT oscillator pin
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Pad Name
PC3/SDO/SSEG21
PC4/SDI/SDA//
SSEG22
PC5/SCK/SCL/
SSEG1/SCOM1
PC6/SCS/SSEG23
PD0/SSEG11
PD1/RX/SSEG12
PD2/TX/SSEG13
PD3/SSEG14
VDD&AVDD
VSS&AVSS
Function
OPT
I/T
PC3
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
O/T
SDO
SIMC0
IFS
—
CMOS SPI data output
SSEG21
SLCDC3
—
SSEG Software controlled LCD segment output
PC4
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
SDI
SIMC0
IFS
ST
SDA
SIMC0
IFS
ST
SSEG22
SLCDC4
—
SSEG Software controlled LCD segment output
PC5
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
SCK
SIMC0
IFS
ST
CMOS SPI serial clock
SCL
SIMC0
IFS
ST
NMOS I2C clock line
SSEG1
SLCDC0
SLCDC1
—
SSEG Software controlled LCD segment output
SCOM1
SLCDC0
SLCDC1
—
SCOM Software controlled LCD common output
PC6
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
SCS
SLCDC0
SIMC0 IFS
ST
CMOS SPI slave select
SSEG23
SLCDC4
—
SSEG Software controlled LCD segment output
PD0
PDPU
ST
CMOS General purpose I/O. Register enabled pull-up.
SSEG11
SLCDC2
—
SSEG Software controlled LCD segment output
PD1
PDPU
ST
CMOS General purpose I/O. Register enabled pull-up.
RX
UCR1
UCR2
ST
SSEG12
SLCDC2
—
SSEG Software controlled LCD segment output
PD2
PDPU
ST
CMOS General purpose I/O. Register enabled pull-up.
TX
UCR1
UCR2
—
CMOS UART TX serial data output
SSEG13
SLCDC2
—
SSEG Software controlled LCD segment output
PD3
PDPU
ST
CMOS General purpose I/O. Register enabled pull-up.
SSEG14
SLCDC3
—
SSEG Software controlled LCD segment output
VDD
—
PWR
—
Positive power supply
AVDD
—
PWR
—
A/D converter positive power supply
VSS
—
PWR
—
Negative power supply, ground.
AVSS
—
PWR
—
A/D converter negative power supply, ground.
—
Description
SPI data input
NMOS I2C data line
—
UART RX serial data input
Note: I/T: Input type;
O/T: Output type;
OPT: Optional by configuration option (CO) or register option;
CO: Configuration option;
ST: Schmitt Trigger input; AN: Analog input;
CMOS: CMOS output;
NMOS: NMOS output;
AO: Analog output;
SSEG: Software controlled LCD SEG;
SCOM: Software controlled LCD COM;
HXT: High frequency crystal oscillator; LXT: Low frequency crystal oscillator
PWR: Power
* The AVDD pin is internally bonded together with the VDD pin while the AVSS pin is internally bonded
together with the VSS pin.
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.
Rev. 1.10
16
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
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
IOH Total........................................................................................................................................-80mA
IOL 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 these devices. Functional operation of
these devices at other conditions beyond those listed in the specification is not implied and
prolonged exposure to extreme conditions may affect devices reliability.
D.C. Characteristics
Ta=25°C
Symbol
Parameter
Test Conditions
Conditions
VDD
fSYS= fHXT=8MHz
Operating Voltage (HXT)
—
Operating Current (HXT)
Operating Current (HIRC)
Max.
Unit
2.2
—
5.5
V
fSYS= fHXT=12MHz
2.7
—
5.5
V
fSYS= fHXT=16MHz
4.5
—
5.5
V
4.5
—
5.5
V
fSYS= fHIRC=8MHz
2.2
—
5.5
V
— fSYS= fHIRC=12MHz
2.7
—
5.5
V
fSYS= fHIRC=16MHz
4.5
—
5.5
V
3V fSYS=fH= fHXT=8MHz
5V No load, all peripherals off
—
1.0
1.5
mA
—
2.5
4.0
mA
3V fSYS=fH= fHXT=12MHz
5V No load, all peripherals off
—
1.5
2.5
mA
—
3.5
5.5
mA
fSYS=fH= fHXT=16MHz, no load,
5V
all peripherals off
—
4.5
7.0
mA
fSYS=fH= fHXT=20MHz, no load,
all peripherals off
—
5.5
8.5
mA
5V
IDD
Typ.
fSYS= fHXT=20MHz
VDD
Operating Voltage (HIRC)
Min.
3V fSYS=fH= fHIRC=8MHz
5V No load, all peripherals off
—
2.0
2.8
mA
—
3.0
4.5
mA
3V fSYS=fH= fHIRC=12MHz
5V No load, all peripherals off
—
3.0
4.2
mA
—
4.5
6.7
mA
—
6.0
9.0
mA
5V
fSYS=fH= fHIRC=16MHz
No load, all peripherals off
Operating Current (LXT)
3V fSYS=fSUB=fLXT=32.768kHz
5V No load, all peripherals off
—
10
20
μA
—
30
50
μA
Operating Current (LIRC)
3V fSYS=fSUB=fLIRC=32kHz
5V No load, all peripherals off
—
10
20
μA
—
30
50
μA
Rev. 1.10
17
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Symbol
Parameter
Standby Current (IDLE0 Mode)
Standby Current (IDLE1 Mode)
ISTB
Test Conditions
Conditions
VDD
3V No load, all peripherals off,
5V fSUB on
VIH
IOL
IOH
Rev. 1.10
Unit
3
5
μA
5
10
μA
3V fSYS=fHXT=8MHz on, fSUB on
5V No load, all peripherals off
—
0.5
1.0
mA
—
1.0
2.0
mA
3V fSYS=fHXT=12MHz on, fSUB on
5V No load, all peripherals off
—
0.6
1.2
mA
—
1.2
2.4
mA
5V
fSYS=fHXT=16MHz on, fSUB on
No load, all peripherals off
—
2.0
4.0
mA
5V
fSYS=fHXT=20MHz on, fSUB on
No load, all peripherals off
—
2.5
5.0
mA
3V fSYS=fHIRC=8MHz on, fSUB on
5V No load, all peripherals off
—
0.8
1.6
mA
—
1.0
2.0
mA
3V fSYS=fHIRC=12MHz on, fSUB on
5V No load, all peripherals off
—
1.2
2.4
mA
—
1.5
3.0
mA
—
2.0
4.0
mA
μA
3V fSUB off, WDT disable
5V No load, all peripherals off
—
—
1.0
—
—
2.0
μA
—
—
3.0
μA
—
—
5.0
μA
Input Low Voltage for I/O Ports
or Input Pins
5V
—
0
—
1.5
V
—
—
0
—
0.2VDD
V
Input High Voltage for I/O Ports
or Input Pins
5V
—
3.5
—
5.0
V
—
—
Sink Current for I/O Port
Source Current for I/O Port
0.8VDD
—
VDD
V
3V VOL = 0.1VDD
16
32
—
mA
5V VOL = 0.1VDD
32
64
—
mA
3V VOH = 0.9VDD,
SLEDCn [m+1, m] = 00
5V n = 0 or 1; m = 0, 2, 4 or 6
-1.0
-2.0
—
mA
-2.0
-4.0
—
mA
3V VOH = 0.9VDD,
SLEDCn [m+1, m] = 01
5V n = 0 or 1; m = 0, 2, 4 or 6
-1.75
-3.5
—
mA
-3.5
-7.0
—
mA
3V VOH = 0.9VDD,
SLEDCn [m+1, m] = 10
5V n = 0 or 1; m = 0, 2, 4 or 6
-2.5
-5.0
—
mA
-5.0
-10.0
—
mA
-5.5
-11.0
—
mA
-11.0
-22.0
—
mA
3V VOH = 0.9VDD,
SLEDCn [m+1, m] = 11
5V n = 0 or 1; m = 0, 2, 4 or 6
RPH
Max.
—
3V fSUB on, WDT enable
Standby Current (SLEEP1 Mode)
5V No load, all peripherals off
VIL
Typ.
—
fSYS=fHIRC=16MHz on, fSUB on
5V
No load, all peripherals off
Standby Current (SLEEP0 Mode)
Min.
Pull-high Resistance for I/O Ports
3V
—
20
60
100
kΩ
5V
—
10
30
50
kΩ
18
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
A.C. Characteristics
Ta=25°C
Symbol
Parameter
System Clock (HXT)
fSYS
System Clock (HIRC)
Test Condition
VDD
Condition
Min.
Typ.
Max. Unit
2.2~5.5V fSYS=fHXT=8MHz
—
8
—
2.7~5.5V fSYS=fHXT=12MHz
—
12
—
MHz
MHz
4.5~5.5V fSYS=fHXT=16MHz
—
16
—
MHz
4.5~5.5V fSYS=fHXT=20MHz
—
20
—
MHz
2.4~5.5V fSYS=fHIRC=8MHz
—
8
—
MHz
2.7~5.5V fSYS=fHIRC=12MHz
—
12
—
MHz
4.5~5.5V fSYS=fHIRC=16MHz
—
16
—
MHz
System Clock (LXT)
2.2~5.5V fSYS=fLXT=32.768kHz
—
32.768
—
kHz
System Clock (LIRC)
2.2~5.5V fSYS=fLIRC=32kHz
—
32
—
kHz
-10%
32
+10% kHz
-50%
32
+60% kHz
0.3
—
—
5V
fLIRC
Low Speed Internal RC oscillator (LIRC)
tTCK
TCKn pin Minimum Input Pulse Width
—
tINT
Interrupt Pin Minimum Input Pulse Width
—
Ta = 25°C
2.2V~5.5V Ta = -40°C to 85°C
—
10
—
—
μs
128
—
—
tHXT
fSYS = fHIRC off
16
—
—
tHIRC
fSYS = fLXT off
128
—
—
tLXT
—
fSYS = fLIRC off
2
—
—
tLIRC
System Start-up Timer Period
(Wake-up from power down mode)
—
fSYS on
2
—
—
tSYS
System reset delay time
(Power-on reset, LVR hardware reset,
LVRC/WDTC software reset)
—
—
25
50
100
ms
System reset delay time
(WDT hardware reset)
—
—
8.3
16.7
33.3
ms
tEERD
EEPROM Read Time
—
—
—
—
4
tSYS
tEEWR
EEPROM Write Time
—
—
—
2
4
ms
tSST
tRSTD
System Start-up Timer Period
(Wake-up from power down mode and
fSYS off)
—
μs
—
fSYS = fHXT off
—
—
Note: tSYS= 1/fSYS
Rev. 1.10
19
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
HIRC Electrical Characteristics
Ta=25°C
Frequency Accuracy trimmed 8MHz at VDD=3V
Symbol
Parameter
Test Conditions
Conditions
VDD
3V
Ta = 25°C
Typ.
Max.
Unit
-2%
8
+2%
MHz
3V ± 0.3V
Ta = 0°C ~ 70°C
-5%
8
+5%
MHz
3V ± 0.3V
Ta = -40°C ~ 85°C
-7%
8
+7%
MHz
MHz
High Speed Internal RC oscillator
2.2V ~ 5.5V Ta = 0°C ~ 70°C
(HIRC)
2.2V ~ 5.5V Ta = -40°C ~ 85°C
fHIRC
Min.
-7%
8
+7%
-10%
8
+10%
MHz
3V
Ta = 25°C
-20%
12
+20%
MHz
3V
Ta = 25°C
-20%
16
+20%
MHz
Min.
Typ.
Max.
Unit
Ta = 25°C
-2%
8
+2%
MHz
5V ± 0.5V
Ta = 0°C ~ 70°C
-5%
8
+5%
MHz
5V ± 0.5V
Ta = -40°C ~ 85°C
-7%
8
+7%
MHz
-7%
8
+7%
MHz
Frequency Accuracy trimmed 8MHz at VDD=5V
Symbol
Parameter
Test Conditions
Conditions
VDD
5V
High Speed Internal RC oscillator
2.2V ~ 5.5V Ta = 0°C ~ 70°C
(HIRC)
2.2V ~ 5.5V Ta = -40°C ~ 85°C
fHIRC
-10%
8
+10%
MHz
5V
Ta = 25°C
-20%
12
+20%
MHz
5V
Ta = 25°C
-20%
16
+20%
MHz
Min.
Typ.
Max.
Unit
-2%
12
+2%
MHz
Frequency Accuracy trimmed 12MHz at VDD=3V
Symbol
Parameter
Test Conditions
Conditions
VDD
3V
fHIRC
Rev. 1.10
Ta = 25°C
3V ± 0.3V
Ta = 0°C ~ 70°C
-5%
12
+5%
MHz
3V ± 0.3V
Ta = -40°C ~ 85°C
-7%
12
+7%
MHz
-7%
12
+7%
MHz
-10%
12
+10%
MHz
High Speed Internal RC oscillator
2.2V ~ 5.5V Ta = 0°C ~ 70°C
(HIRC)
2.2V ~ 5.5V Ta = -40°C ~ 85°C
3V
Ta = 25°C
-20%
8
+20%
MHz
3V
Ta = 25°C
-20%
16
+20%
MHz
20
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Frequency Accuracy trimmed 12MHz at VDD=5V
Symbol
Parameter
Test Conditions
5V
5V ± 0.5V
fHIRC
Min.
Typ.
Max.
Ta = 25°C
-2%
12
+2%
MHz
Ta = 0°C ~ 70°C
-5%
12
+5%
MHz
-7%
12
+7%
MHz
-7%
12
+7%
MHz
-10%
12
+10%
MHz
Conditions
VDD
5V ± 0.5V Ta = -40°C ~ 85°C
High Speed Internal RC oscillator
2.2V ~ 5.5V Ta = 0°C ~ 70°C
(HIRC)
2.2V ~ 5.5V Ta = -40°C ~ 85°C
Unit
5V
Ta = 25°C
-20%
8
+20%
MHz
5V
Ta = 25°C
-20%
16
+20%
MHz
Min.
Typ.
Max.
Unit
Frequency Accuracy trimmed 16MHz at VDD=5V
Symbol
Parameter
Test Conditions
Conditions
VDD
5V
fHIRC
Ta = 25°C
-2%
16
+2%
MHz
5V ± 0.5V
Ta = 0°C ~ 70°C
-5%
16
+5%
MHz
5V ± 0.5V
Ta = -40°C ~ 85°C
-7%
16
+7%
MHz
-7%
16
+7%
MHz
High Speed Internal RC oscillator
2.2V ~ 5.5V Ta = 0°C ~ 70°C
(HIRC)
2.2V ~ 5.5V Ta = -40°C ~ 85°C
-10%
16
+10%
MHz
5V
Ta = 25°C
-20%
8
+20%
MHz
5V
Ta = 25°C
-20%
12
+20%
MHz
A/D Converter Electrical Characteristics
Ta=25°C
Symbol
Parameter
Test Conditions
Conditions
VDD
Min.
Typ.
Max.
Unit
VDD
Operating Voltage
—
—
2.7
—
5.5
V
VADI
Input Voltage
—
—
0
—
VR\EF
V
VREF
Reference Voltage
—
—
2
—
VDD
V
VREF=VDD, tADCK =0.5μs
-3
—
3
LSB
VREF=VDD, tADCK =0.5μs
-4
—
4
LSB
—
1.0
2.0
mA
—
1.5
3.0
mA
3V
DNL
Differential Non-linearity
INL
Integral Non-linearity
IADC
Additional Current Consumption
for A/D Converter Enable
3V
tADCK
Clock Period
—
—
0.5
—
10
μs
tADC
Conversion Time (A/D Sample and Hold
Time)
—
—
—
16
—
tADCK
tON2ST
A/D Converter On-to-Start Time
—
—
4
—
—
μs
Rev. 1.10
5V
3V
5V
5V
No load, tADCK =0.5μs
21
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
LVD/LVR Electrical Characteristics
Ta=25°C
Symbol
VLVR
VLVD
VBG
—
Low Voltage Detector Voltage
—
Bandgap Reference Voltage
Operating Current
tBGS
VBG Turn on Stable Time
LVR Enable, voltage select 2.1V
2.1
LVR Enable, voltage select 2.55V
2.55
LVR Enable, voltage select 3.15V
-5%
3.15
LVR Enable, voltage select 3.8V
3.8
LVD Enable, voltage select 2.0V
2.0
LVD Enable, voltage select 2.2V
2.2
LVD Enable, voltage select 2.4V
2.4
LVD Enable, voltage select 2.7V
LVD Enable, voltage select 3.0V
-5%
2.7
3.0
LVD Enable, voltage select 3.3V
3.3
LVD Enable, voltage select 3.6V
3.6
V
+5%
V
4.0
—
-3% 1.04 +3%
5V LVD/LVR Enable, VBGEN=0
—
20
5V LVD/LVR Enable, VBGEN=1
—
— No load
—
For LVR enable, VBGEN=0,
—
LVD off → on
For LVR disable, VBGEN=0,
LVD off → on
—
+5%
LVD Enable, voltage select 4.0V
—
LVDO stable time
Min. Typ. Max. Unit
Conditions
VDD
Low Voltage Reset Voltage
IOP
tLVDS
Test Conditions
Parameter
V
25
μA
180
200
μA
—
150
μs
—
—
15
μs
—
—
150
μs
tLVR
Minimum Low Voltage Width to Reset
—
—
120
240
480
μs
tLVD
Minimum Low Voltage Width to Interrupt —
—
60
120
240
μs
Comparator Electrical Characteristics
Ta=25°C
Symbol
Parameter
Test Conditions
VDD
Conditions
Min.
Typ.
Max.
Unit
—
5.5
V
VDD
Operating Voltage
—
—
2.2
ICMP
Additional Current Consumption
for comparator enable
3V
—
—
37
56
μA
5V
—
—
130
200
μA
mV
VOS
Input offset voltage
5V
—
-10
—
10
VCM
Common mode voltage range
—
—
VSS
—
VDD-1.4
V
AOL
Open loop gain
5V
—
60
80
—
dB
VHYS
Hysteresis
5V
tRP
Response time
—
Rev. 1.10
Hysteresis function disabled
0
0
5
mV
Hysteresis function enabled
20
40
60
mV
With 100mV overdrive
—
370
560
ns
22
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Software Controlled LCD Driver Electrical Characteristics
Ta=25°C
Symbol
IBIAS
Test Conditions
Parameter
Bias current
Min.
Conditions
VDD
5V
Typ.
Max.
Unit
ISEL[1:0]=00
4.2
8.3
13
μA
ISEL[1:0]=01
8.3
16.7
25
μA
ISEL[1:0]=10
25
50
75
μA
ISEL[1:0]=11
50
100
150
μA
VLCD_H
[(2/3) × VDD] voltage for LCD SCOM/SSEG output 2.2V~5.5V No load
0.645
0.67
0.698
VDD
VLCD_L
[(1/3) × VDD] voltage for LCD SCOM/SSEG output 2.2V~5.5V No load
0.305
0.33
0.355
VDD
Power-on Reset 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
RRVDD
VDD Raising 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
Rev. 1.10
23
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
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 enhanced 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 these
devices suitable for low-cost, high-volume production for controller applications.
Clocking and Pipelining
The main system clock, derived from either a HXT, LXT, 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.


   
   
System Clocking and Pipelining
Rev. 1.10
24
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
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.
  
    
 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.
Device
Program Counter
High Byte
Low Byte (PCL)
HT66F0175
PC10~PC8
PC7~PC0
HT66F0185
PC11~PC8
PC7~PC0
Program Counter
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. 1.10
25
November 21, 2014
HT66F0175/HT66F0185
A/D 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 has multiple levels and 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.
P�og�a� Counte�
Top of Stack
Stack Level 1
Stack Level �
Stack
Pointe�
Stack Level 3
Botto� of Stack
Stack Level 8
:
:
:
P�og�a� Me�o�y
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. 1.10
26
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Flash Program Memory
The Program Memory is the location where the user code or program is stored. For these devices
series the Program Memory are 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, these Flash devices offer users the flexibility to
conveniently debug and develop their applications while also offering a means of field programming
and updating.
Device
Capacity
HT66F0175
2K × 16
HT66F0185
4K × 16
Structure
The Program Memory has a capacity of 2K×16 to 4K×16 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 registers.
000H
HT66F0175
HT66F0185
Initialisation Vecto�
Initialisation Vecto�
Inte��upt Vecto�s
Inte��upt Vecto�s
Look-up Ta�le
Look-up Ta�le
00�H
0��H
0�8H
n00H
nFFH
7FFH
16 �its
FFFH
16 �its
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 these devices reset for program initialisation. After a device reset is
initiated, the program will jump to this location and begin execution.
Rev. 1.10
27
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
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 and TBHP. These registers
define 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”.
The accompanying diagram illustrates the addressing data flow of the look-up table.
A d d re s s
L a s t p a g e o r
T B H P R e g is te r
T B L P R e g is te r
D a ta
1 6 b its
R e g is te r T B L H
U s e r S e le c te d
R e g is te r
H ig h B y te
L o w B y te
Table Program Example
The accompanying example shows how the table pointer and table data is defined and retrieved from
the device. This example uses raw table data located in the last page which is stored there using the
ORG statement. The value at this ORG statement is “0F00H” which refers to the start address of the
last page within the 4K Program Memory of the device. The table pointer low byte register 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 “0F06H” 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 pointed by the
TBHP register if the “TABRD [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 “TABRD
[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.
Rev. 1.10
28
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
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 is referenced
mov tblp,a ; to the last page or the page that tbhp pointed
mov a,0fh ; initialise high table pointer
movtbhp,a
:
tabrd tempreg1 ; transfers value in table referenced by table pointer data at program
; memory address “0F06H” transferred to tempreg1 and TBLH
dec tblp ; reduce value of table pointer by one
tabrd tempreg2 ; transfers value in table referenced by table pointer data at program
; memory address “0F05H” transferred to tempreg2 and TBLH in this
; example the data “1AH” is transferred to tempreg1 and data “0FH” to
; register tempreg2
:
org 0F00h ; sets initial address of program memory
dc 00Ah, 00Bh, 00Ch, 00Dh, 00Eh, 00Fh, 01Ah, 01Bh
:
In Circuit Programming – ICP
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 incircuit 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 reinsertion of the device.
Holtek Writer Pins
MCU Programming Pins
Pin Description
ICPDA
PA0
Programming Serial Data/Address
ICPCK
PA2
Programming Clock
VDD
VDD
Power Supply
VSS
VSS
Ground
The Program Memory and EEPROM data memory can 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. 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.
During the programming process, the user must take care of the ICPDA and ICPCK pins for data
and clock programming purposes to ensure that no other outputs are connected to these two pins.
Rev. 1.10
29
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
W r ite r C o n n e c to r
S ig n a ls
M C U
P r o g r a m m in g
P in s
V D D
W r ite r _ V D D
IC P D A
P A 0
IC P C K
P A 2
W r ite r _ V S S
V S S
*
*
T o o th e r C ir c u it
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 named HT66V01x5 which is used to emulate the real MCU device named
HT66F01x5. The EV chip device also provides the “On-Chip Debug” function to debug the real
MCU device during development process. The EV chip and real MCU devices, HT66V01x5 and
HT66F01x5, are almost functional compatible except the “On-Chip Debug” function. Users can
use the EV chip device to emulate the real MCU device behaviors 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 device for debugging, the corresponding pin functions shared with the OCDSDA
and OCDSCK pins in the real 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 more detailed OCDS information, refer to the corresponding
document named “Holtek e-Link for 8-bit MCU OCDS User’s Guide”.
Rev. 1.10
Holtek e-Link Pins
EV Chip OCDS Pins
Pin Description
OCDSDA
OCDSDA
On-Chip Debug Support Data/Address input/output
OCDSCK
OCDSCK
On-Chip Debug Support Clock input
VDD
VDD
Power Supply
VSS
VSS
Ground
30
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Data Memory
The Data Memory is an 8-bit wide RAM internal memory and is the location where temporary
information is stored.
Structure
Divided into two banks, 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.
The address range of the Special Purpose Data Memory for the device is from 00H to 7FH while the
address range of the General Purpose Data Memory is from 80H to FFH.
Device
Capacity
Banks
HT66F0175
128 × 8
0: 80H~FFH
HT66F0185
256 × 8
0: 80H~FFH
1: 80H~FFH
Data Memory Summary
00H
00H
Special
Pu�pose Data
Me�o�y
�0H: EEC
(Bank 1)
Special
Pu�pose Data
Me�o�y
�0H:EEC
(Bank 1)
7FH
80H
7FH
80H
Gene�al
Pu�pose Data
Me�o�y
Gene�al
Pu�pose Data
Me�o�y
FFH
FFH
Bank 0
Bank 0
Bank 1
HT66F0185
HT66F0175
Data Memory Structure
Rev. 1.10
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November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
00H
01H
0�H
03H
0�H
05H
06H
07H
08H
09H
0AH
0BH
0CH
0DH
0EH
0FH
10H
11H
1�H
13H
1�H
15H
16H
17H
18H
19H
1AH
1BH
1CH
1DH
1EH
1FH
�0H
�1H
��H
�3H
��H
�5H
�6H
�7H
�8H
�EH
�FH
30H
31H
3�H
33H
3�H
35H
36H
Bank 0� 1
IAR0
MP0
IAR1
MP1
BP
ACC
PCL
TBLP
TBLH
TBHP
STATUS
SMOD
LVDC
I�TEG
I�TC0
I�TC1
I�TC�
MFI0
MFI1
MFI�
PA
PAC
PAPU
PAWU
TMPC
WDTC
TBC
CTRL
LVRC
EEA
EED
SADOL
SADOH
SADC0
SADC1
SADC�
PB
PBC
PBPU
37H
38H
39H
3AH
3BH
3CH
3DH
3EH
3FH
�0H
�1H
��H
�3H
��H
�5H
�6H
�7H
�8H
�9H
�AH
�BH
�CH
�DH
�EH
�FH
50H
51H
5�H
Bank 0 Bank 1
TM1C0
TM1C1
TM1DL
TM1DH
TM1AL
TM1AH
TM1RPL
TM1RPH
00H
01H
0�H
03H
0�H
05H
06H
07H
08H
09H
0AH
0BH
0CH
0DH
0EH
0FH
10H
11H
1�H
13H
1�H
15H
16H
17H
18H
19H
1AH
1BH
1CH
1DH
1EH
1FH
�0H
�1H
��H
�3H
��H
�5H
�6H
�7H
�8H
�9H
�AH
�BH
�CH
�DH
�EH
�FH
30H
31H
3�H
33H
3�H
35H
36H
EEC
PC
PCC
PCPU
ACERL
SIMC0
SIMC1
SIMD
SIMA/SIMC�
SIMTOC
SLCDC0
SLCDC1
SLCDC�
SLCDC3
SLEDC0
SLEDC1
IFS
7FH
: Unused� �ead as 00H
TM0C0
TM0C1
TM0DL
TM0DH
TM0AL
TM0AH
TM0RPL
TM0RPH
Bank 0� 1
IAR0
MP0
IAR1
MP1
BP
ACC
PCL
TBLP
TBLH
TBHP
STATUS
SMOD
LVDC
I�TEG
I�TC0
I�TC1
I�TC�
MFI0
MFI1
MFI�
PA
PAC
PAPU
PAWU
TMPC
WDTC
TBC
CTRL
LVRC
EEA
EED
SADOL
SADOH
SADC0
SADC1
SADC�
PB
PBC
PBPU
TM�C0
TM�C1
TM�DL
TM�DH
TM�AL
TM�AH
TM�RP
TM0C0
TM0C1
TM0DL
TM0DH
TM0AL
TM0AH
TM0RP
37H
38H
39H
3AH
3BH
3CH
3DH
3EH
3FH
�0H
�1H
��H
�3H
��H
�5H
�6H
�7H
�8H
�9H
�AH
�BH
�CH
�DH
�EH
�FH
50H
51H
5�H
53H
5�H
55H
56H
57H
58H
59H
5AH
Bank 0 Bank 1
TM1C0
TM1C1
TM1DL
TM1DH
TM1AL
TM1AH
TM1RPL
TM1RPH
CPC
EEC
PC
PCC
PCPU
ACERL
SIMC0
SIMC1
SIMD
SIMA/SIMC�
SIMTOC
SLCDC0
SLCDC1
SLCDC�
SLCDC3
SLCDC�
SLEDC0
SLEDC1
IFS
PD
PDC
PDPU
USR
UCR1
UCR�
BRG
TXR_RXR
7FH
: Unused� �ead as 00H
HT66F0185
HT66F0175
Special Purpose Data Memory Structure
Rev. 1.10
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HT66F0175/HT66F0185
A/D 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 only from Bank 0 while the IAR1 register together
with MP1 register pair can access data from any Data Memory 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
The 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 together with IAR1 are
used to access data from all data banks according to the corresponding BP register.
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
RAM addresses.
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Bank Pointer – BP
For the HT66F0185 device, 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 – HT66F0185
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.
Look-up Table Registers – TBLP, TBHP, TBLH
These three special function registers are used to control operation of the look-up table which is
stored in the Program Memory. TBLP and TBHP are the table pointer and indicates the location
where the table data is located. Their value must be setup before any table read commands are
executed. Their 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.
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
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.
Rev. 1.10
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November 21, 2014
HT66F0175/HT66F0185
A/D 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/W
—
—
R
R
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” instructin
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 substraction
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
The “C” flag is also affected by a rotate through carry instruction.
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
EEPROM Data Memory
These 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 re-programmable 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 up to 128×8 bits for the series of devices. Unlike the
Program Memory and RAM Data Memory, the EEPROM Data Memory is not directly mapped
into memory space and is therefore not directly addressable 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
an address and data register in bank 0 and a single control register in bank 1.
Device
Capacity
Address
HT66F0175
64 × 8
00H ~ 3FH
HT66F0185
128 × 8
00H ~ 7FH
EEPROM Registers
Three registers control the overall operation of the internal EEPROM Data Memory. These are the
address register, EEA, the data register, EED and a single control register, EEC. As both the EEA
and EED registers are located in bank 0, they can be directly accessed in the same was as any other
Special Function Register. The EEC register, however, being located in bank 1, can 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 MP1Memory Pointer
register 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 (HT66F0175)
—
—
EEA5
EEA4
EEA3
EEA2
EEA1
EEA0
EEA (HT66F0185)
—
EEA6
EEA5
EEA4
EEA3
EEA2
EEA1
EEA0
EED
D7
D6
D5
D4
D3
D2
D1
D0
EEC
—
—
—
—
WREN
WR
RDEN
RD
EEPROM Registers List
EEA Register – HT66F0175
Bit
7
6
5
4
3
2
1
0
Name
—
—
EEA5
EEA4
EEA3
EEA2
EEA1
EEA0
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 5~0EEA5~EEA0: Data EEPROM address bit 5 ~ bit0
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
EEA Register – HT66F0185
Bit
7
6
5
4
3
2
1
0
Name
—
EEA6
EEA5
EEA4
EEA3
EEA2
EEA1
EEA0
R/W
—
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
—
0
0
0
0
0
0
0
2
1
0
Bit 7
Unimplemented, read as “0”
Bit 6~0EEA6~EEA0: Data EEPROM address bit 6 ~ bit0
EED 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
4
3
2
1
0
Bit 7~0D7~D0: Data EEPROM data bit 7~bit0
EEC Register
Bit
7
6
5
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 can not be set to “1” at the same time in one instruction. The
WR and RD can not be set to “1” at the same time.
Rev. 1.10
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HT66F0175/HT66F0185
A/D 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 register, 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. However, as
the EEPROM is contained within a Multi-function Interrupt, the associated multi-function interrupt
enable bit must also be set. When an EEPROM write cycle ends, the DEF request flag and its
associated multi-function interrupt request flag will both be set. If the global, EEPROM and Multifunction interrupts are enabled and the stack is not full, a jump to the associated Multi-function
Interrupt vector will take place. When the interrupt is serviced only the Multi-function interrupt flag
will be automatically reset, the EEPROM interrupt flag must be manually reset by the application
program.
Rev. 1.10
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November 21, 2014
HT66F0175/HT66F0185
A/D 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 register could be normally cleared to zero as this would inhibit access to bank 1 where 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 Example
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 BP
; 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. 1.10
; user defined address
; user defined data
; setup memory pointer MP1
; MP1 points to EEC register
; setup Bank Pointer BP
; set WREN bit, enable write operations
; start Write Cycle - set WR bit
; check for write cycle end
; disable EEPROM write
40
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Oscillator
Various oscillator types 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 relevant control 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. External oscillators requiring some external
components as well as fully integrated internal oscillators, requiring no external components, are
provided to form a wide range of both fast and slow system oscillators. All oscillator options are
selected through configuration options. The higher frequency oscillators provide higher performance
but carry with it the disadvantage of higher power requirements, while the opposite is of course true
for the lower frequency oscillators. With the capability of dynamically switching between fast and
slow system clock, the device has the flexibility to optimize the performance/power ratio, a feature
especially important in power sensitive portable applications.
Name
Frequency
Pins
High Speed External Crystal
Type
HXT
400 kHz~20 MHz
OSC1/OSC2
High Speed Internal RC
HIRC
8/12/16 MHz
—
Low Speed External Crystal
LXT
32.768 kHz
XT1/XT2
Low Speed Internal RC
LIRC
32 kHz
—
Oscillator Types
System Clock Configurations
There are four methods of generating the system clock, two high speed oscillators for all devices and
two low speed oscillators. The high speed oscillator is the external crystal/ceramic oscillator, HXT,
and the internal 8/12/16MHz RC oscillator, HIRC. The two low speed oscillators are the internal 32
kHz RC oscillator, LIRC, and the external 32.768 kHz crystal oscillator, LXT. 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.
The actual source clock used for each of the high and low speed oscillators is chosen via
configuration options. The frequency of the slow speed or high speed system clock is also
determined using the HLCLK bit and CKS2~CKS0 bits in the SMOD register. Note that two
oscillator selections must be made namely one high speed and one low speed system oscillators.
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A/D 8-Bit Flash MCU with EEPROM
fH
High Speed
Oscillato�
fH/�
fH/�
HXT
fH/8
P�escale�
fH
HIRC
fH/16
fSYS
fH/3�
fH/6�
Low Speed
Oscillato�
High Speed Oscillato�
Configu�ation Option
LXT
Fast Wake-up f�o� IDLE
o� SLEEP Mode Cont�ol
(fo� HXT only )
HLCLK�
CKS�~CKS0
fSUB
fSUB
LIRC
Low Speed Oscillato�
Configu�ation Option
System Clock Configurations
External Crystal/Ceramic Oscillator – HXT
The External Crystal/Ceramic System Oscillator is one of the high frequency oscillator choices,
which is selected via configuration option. For most crystal oscillator configurations, the simple
connection of a crystal across OSC1 and OSC2 will create the necessary phase shift and feedback for
oscillation, without requiring external capacitors. However, for some crystal types and frequencies,
to ensure oscillation, it may be necessary to add two small value capacitors, C1 and C2. Using a
ceramic resonator will usually require two small value capacitors, C1 and C2, to be connected as
shown for oscillation to occur. The values of C1 and C2 should be selected in consultation with the
crystal or resonator manufacturer’s specification.
For oscillator stability and to minimise the effects of noise and crosstalk, it is important to ensure
that the crystal and any associated resistors and capacitors along with interconnecting lines are all
located as close to the MCU as possible.
     Crystal/Resonator Oscillator
HXT Oscillator C1 and C2 Values
Crystal Frequency
C1
C2
12MHz
0 pF
0 pF
8MHz
0 pF
0 pF
4MHz
0 pF
0 pF
1MHz
100 pF
100 pF
Note: C1 and C2 values are for guidance only.
Crystal Recommended Capacitor Values
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A/D 8-Bit Flash MCU with EEPROM
Internal High Speed RC Oscillator – HIRC
The internal RC oscillator is a fully integrated system oscillator requiring no external components.
The internal RC oscillator has three fixed frequencies of 8MHz, 12MHz, 16MHz. 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 either 3V or 5V and at a
temperature of 25°C degrees, the fixed oscillation frequency of 8MHz, 12MHz or 16MHz will have
a tolerance within 2%. Note that if this internal system clock option is selected, as it requires no
external pins for its operation, I/O pins are free for use as normal I/O pins.
External 32.768 kHz Crystal Oscillator – LXT
The External 32.768kHz Crystal System Oscillator is one of the low frequency oscillator choices,
which is selected via configuration option. This clock source has a fixed frequency of 32.768 kHz
and requires a 32.768 kHz crystal to be connected between pins XT1 and XT2. The external resistor
and capacitor components connected to the 32.768 kHz crystal are necessary to provide oscillation.
For applications where precise frequencies are essential, these components may be required to
provide frequency compensation due to different crystal manufacturing tolerances. During power-up
there is a time delay associated with the LXT oscillator waiting for it to start-up.
When the microcontroller enters the SLEEP or IDLE Mode, the system clock is switched off to stop
microcontroller activity and to conserve power. However, in many microcontroller applications
it may be necessary to keep the internal timers operational even when the microcontroller is in
the SLEEP or IDLE Mode. To do this, another clock, independent of the system clock, must be
provided.
However, for some crystals, to ensure oscillation and accurate frequency generation, it is necessary
to add two small value external capacitors, C1 and C2. The exact values of C1 and C2 should
be selected in consultation with the crystal or resonator manufacturer specification. The external
parallel feedback resistor, RP, is required.
Some configuration options determine if the XT1/XT2 pins are used for the LXT oscillator or as I/O
or other pin-shared functional pins.
• If the LXT oscillator is not used for any clock source, the XT1/XT2 pins can be used as normal I/
O or other pin-shared functional pins.
• If the LXT oscillator is used for any clock source, the 32.768 kHz crystal should be connected to
the XT1/XT2 pins.
For oscillator stability and to minimise the effects of noise and crosstalk, it is important to ensure
that the crystal and any associated resistors and capacitors along with interconnecting lines are all
located as close to the MCU as possible.
‚   
­ €
  ‚  External LXT Oscillator
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A/D 8-Bit Flash MCU with EEPROM
LXT Oscillator C1 and C2 Values
Crystal Frequency
C1
C2
32.768kHz
10pF
10pF
Note: 1. C1 and C2 values are for guidance only.
2. RP=5MΩ~10MΩ is recommended.
32.768kHz Crystal Recommended Capacitor Values
LXT Oscillator Low Power Function
The LXT oscillator can function in one of two modes, the Quick Start Mode and the Low Power
Mode. The mode selection is executed using the LXTLP bit in the TBC register.
LXTLP
LXT Operating Mode
0
Quick Start
1
Low-Power
After power on, the LXTLP bit will be automatically cleared to zero ensuring that the LXT oscillator
is in the Quick Start operating mode. In the Quick Start Mode the LXT oscillator will power up
and stabilise quickly. However, after the LXT oscillator has fully powered up it can be placed
into the Low-power mode by setting the LXTLP bit high. The oscillator will continue to run but
with reduced current consumption, as the higher current consumption is only required during the
LXT oscillator start-up. In power sensitive applications, such as battery applications, where power
consumption must be kept to a minimum, it is therefore recommended that the application program
sets the LXTLP bit high about 2 seconds after power-on. It should be noted that, no matter what
condition the LXTLP bit is set to, the LXT oscillator will always function normally and the only
difference is that it will take more time to start up if in the Low-power mode.
Internal 32kHz Oscillator – LIRC
The Internal 32kHz System Oscillator is one of the low frequency oscillator choices, which is
selected via configuration option. 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. As a result, at a power supply of 5V and at a temperature of
25°C degrees, the fixed oscillation frequency of 32kHz will have a tolerance within 10%.
Supplementary Oscillators
The low speed oscillators, in addition to providing a system clock source are also used to provide
a clock source to two other device functions. These are the Watchdog Timer and the Time Base
Interrupts.
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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 these devices 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 many different clock sources for both the CPU and peripheral function operation.
By providing the user with a wide range of clock options using configuration options and 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 low frequency fSUB source, and
is selected using the HLCLK bit and CKS2~CKS0 bits in the SMOD register. The high speed system
clock can be sourced from either an HXT or HIRC oscillator, selected via a configuration option.
The low speed system clock source can be sourced from internal clock fSUB. If fSUB is selected then it
can be sourced by either the LXT or LIRC oscillator, selected via a configuration option. The other
choice, which is a divided version of the high speed system oscillator has a range of fH/2~ fH/64.
There are two additional internal clocks for the peripheral circuits, the substitute clock, fSUB, and
the Time Base clock, fTBC. Each of these internal clocks is sourced by either the LXT or LIRC
oscillators, selected via configuration options. The fSUB clock is used to provide a substitute clock for
the microcontroller just after a wake-up has occurred to enable faster wake-up times.
fH
High Speed
Oscillato�
fH/�
fH/�
HXT
HIRC
fH/8
P�escale�
fH
fH/16
fSYS
fH/3�
fH/6�
Low Speed
Oscillato�
LXT
High Speed Oscillato�
Configu�ation Option
Fast Wake-up f�o� IDLE
o� SLEEP Mode Cont�ol
(fo� HXT only )
HLCLK�
CKS�~CKS0
fSUB
fSUB
LIRC
fSUB
Low Speed Oscillato�
Configu�ation Option
fSUB
IDLE�
WDT
fTBC
fTBC
fTB
fSYS/�
Ti�e Base
TBCK
Device Clock Configurations
Note: When the system clock source fSYS is switched to fSUB from fH, the high speed oscillator will
stop to conserve the power. Thus there is no fH~fH/64 for peripheral circuit to use.
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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 Mode, are used when the microcontroller CPU is switched off to
conserve power.
Operation Mode
Description
CPU
fSYS
fSUB
fTBC
NORMAL
On
fH~fH/64
On
On
SLOW
On
fSUB
On
On
IDLE0
Off
Off
On
On
IDLE1
Off
On
On
On
SLEEP0
Off
Off
Off
Off
SLEEP1
Off
Off
On
Off
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 by one of the high speed oscillators.
This mode operates allowing the microcontroller to operate normally with a clock source will come
from one of the high speed oscillators, either the HXT or HIRC oscillators. 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 one of the low speed oscillators, either the LXT
or the 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 SLEEP0 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, the fSUB clock will also be
stopped and the Watchdog Timer function is disabled. In this mode, the LVDEN must be set to “0”.
If the LVDEN is set to “1”, it won’t enter the SLEEP0 Mode.
SLEEP1 Mode
The SLEEP1 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 fSUB clock 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 CTRL 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.
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A/D 8-Bit Flash MCU with EEPROM
IDLE1 Mode
The IDLE1 Mode is entered when an HALT instruction is executed and when the IDLEN bit in the
SMOD register is high and the FSYSON bit in the CTRL 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.
Control Registers
A single register, SMOD, is used for overall control of the internal clocks within the devices.
SMOD Register
Bit
7
6
5
4
3
2
1
0
Name
CKS2
CKS1
CKS0
FSTEN
LTO
HTO
IDLEN
HLCLK
R/W
R/W
R/W
R/W
R/W
R
R
R/W
R/W
POR
0
0
0
0
0
0
1
1
Bit 7~5CKS2~CKS0: System clock selection when HLCLK is “0”
000: fSUB
001: fSUB
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 either the LXT or LIRC, a divided
version of the high speed system oscillator can also be chosen as the system clock
source.
Bit 4FSTEN: Fast Wake-up Control (only for HXT)
0: Disable
1: Enable
This is the Fast Wake-up Control bit which determines if the fSUB clock source is
initially used after the device wakes up. When the bit is high, the fSUB clock source can
be used as a temporary system clock to provide a faster wake up time as the fSUB clock
is available.
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 128 clock cycles if the LXT oscillator is used and 1~2
clock cycles if the LIRC oscillator is used.
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A/D 8-Bit Flash MCU with EEPROM
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
devices are 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. The flag will be low when in the SLEEP or IDLE0 Mode but after a wakeup has occurred, the flag will change to a high level after 512 clock cycles if the HXT
oscillator is used and after 15~16 clock cycles if the HIRC oscillator is used.
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 execured, the
device will enter the IDLE mode. In the IDLE mode the CPU will stop running but
the system clock will continye to keep the peripheral functions operational, if the
FSYSON bit is high. If the FSYSON bit is low, the CPU and the system clock will all
stop in IDLE0 mode. If the bit is low, the devices will enter the SLEEP mode when a
HALT instruction is executed.
Bit 0HLCLK: System clock selection
0: fH/2~fH/64 or fSUB
1: fH
This bit is used to select if the fH clock or the fH/2~fH/64 or fSUB clock is used as
the system clock. When the bit is high the fH clock will be selected and if low the
fH/2~fH/64 or fSUB clock will be selected. When system clock switches from the fH
clock to the fSUB clock and the fH clock will be automatically switched off to conserve
power.
CTRL Register
Bit
7
6
5
4
3
2
1
0
Name
FSYSON
—
—
—
—
R/W
R/W
—
—
—
—
LVRF
LRF
WRF
R/W
R/W
POR
0
—
—
—
—
R/W
x
0
0
“x”: unknown
Bit 7FSYSON: fSYS Control in IDLE Mode
0: Disable
1: Enable
This bit is used to control whether the system clock is switched on or not in the IDLE
Mode. If this bit is set to “0”, the system clock will be switched off in the IDLE Mode.
However, the system clock will be switched on in the IDLE Mode when the FSYSON
bit is set to “1”.
Bit 6~3
Unimplemented, read as “0”
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.
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A/D 8-Bit Flash MCU with EEPROM
Fast Wake-up
To minimise power consumption the device can enter the SLEEP or IDLE0 Mode, where the system
clock source to the devices will be stopped. However when the devices are woken up again, it can
take a considerable time for the original system oscillator to restart, stabilise and allow normal
operation to resume. To ensure the devices are up and running as fast as possible a Fast Wakeup function is provided, which allows fSUB, namely either the LXT or LIRC oscillator, to act as a
temporary clock to first drive the system until the original system oscillator has stabilised. As the
clock source for the Fast Wake-up function is fSUB, the Fast Wake-up function is only available in
the SLEEP1 and IDLE0 modes. When the devices are woken up from the SLEEP0 mode, the Fast
Wake-up function has no effect because the fSUB clock is stopped. The Fast Wake-up enable/disable
function is controlled using the FSTEN bit in the SMOD register.
If the HXT oscillator is selected as the NORMAL Mode system clock, and if the Fast Wake-up
function is enabled, then it will take one to two tSUB clock cycles of the LIRC or LXT oscillator for
the system to wake-up. The system will then initially run under the fSUB clock source until 512 HXT
clock cycles have elapsed, at which point the HTO flag will switch high and the system will switch
over to operating from the HXT oscillator.
If the HIRC oscillator or LIRC oscillator is used as the system oscillator then it will take 15~16
clock cycles of the HIRC or 1~2 cycles of the LIRC to wake up the system from the SLEEP or
IDLE0 Mode. The Fast Wake-up bit, FSTEN will have no effect in these cases.
System FSTEN
Oscillator
Bit
Wake-up Time
(SLEEP0 Mode)
Wake-up Time
(SLEEP1 Mode)
Wake-up Time
(IDLE0 Mode)
Wake-up Time
(IDLE1 Mode)
128 HXT cycles
128 HXT cycles
1
128 HXT cycles
1~2 fSUB cycles
(System runs with fSUB first for 512 HXT cycles and 1~2 HXT cycles
then switches over to run with the HXT clock)
HIRC
x
15~16 HIRC cycles 15~16 HIRC cycles
1~2 HIRC cycles
LIRC
x
1~2 LIRC cycles
1~2 LIRC cycles
1~2 LIRC cycles
LXT
x
128 HXT cycles
1~2 LXT cycles
1~2 LXT cycles
0
HXT
1~2 HXT cycles
“x”: don’t care
Wake-up Times
Note that if the Watchdog Timer is disabled, which means that the LXT and LIRC are all both off,
then there will be no Fast Wake-up function available when the devices wake-up from the SLEEP0
Mode.
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Operating Mode Switching
These devices 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 devices enter the IDLE Mode or the SLEEP Mode is
determined by the condition of the IDLEN bit in the SMOD register and the FSYSON bit in the
CTRL register.
When the HLCLK bit switches to a low level, which implies that clock source is switched from the
high speed clock, fH, to the clock source, fH/2~fH/64 or fSUB. If the clock is from the fSUB, 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. The accompamying chart shows what happens when the
devices move between the various operating modes.
NORMAL
fSYS=fH~fH/6�
fH on
CPU �un
fSYS on
fSUB on
fTBC on
SLOW
fSYS=fSUB
fSUB on
CPU �un
fSYS on
fH off
fTBC on
SLEEP0
IDLE0
HALT inst�uction executed
HALT inst�uction executed
CPU stop
IDLE�=0
fSYS off
fSUB off
CPU stop
IDLE�=1
FSYSO�=0
fSYS off
fSUB on
fTBC off
fTBC on
WDT & LVD off
SLEEP1
HALT inst�uction executed
CPU stop
IDLE�=0
fSYS off
fSUB on
fTBC off
CPU stop
IDLE�=1
FSYSO�=1
fSYS on
fSUB on
fTBC on
WDT on
Rev. 1.10
IDLE1
HALT inst�uction executed
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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 set the HLCLK bit
to “0” and set 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 LXT or LIRC oscillator determined by the configuration
option and therefore requires this oscillator to be stable before full mode switching occurs. This is
monitored using the LTO bit in the SMOD register.
NORMAL Mode
CKS�~CKS0 = 00xB &
HLCLK = 0
SLOW Mode
WDT and LVD a�e all off
IDLE�=0
HALT inst�uction is executed
SLEEP0 Mode
WDT is on
IDLE�=0
HALT inst�uction is executed
SLEEP1 Mode
IDLE�=1� FSYSO�=0
HALT inst�uction is executed
IDLE0 Mode
IDLE�=1� FSYSO�=1
HALT inst�uction is executed
IDLE1 Mode
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A/D 8-Bit Flash MCU with EEPROM
SLOW Mode to NORMAL Mode Switching
In SLOW mode the system uses either the LXT or LIRC low speed system oscillator. To switch
back to the NARMAL 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 field is set to “010”, “011”, “100”, “101”, “110”
or “111”. As a certain amount of time will be required for high speed system oscillator stabilization
depends upon which high speed system oscillator type is used.
SLOW Mode
CKS2~CKS0 ≠ 000B or 001B
as HLCLK = 0 or HLCLK = 1
NORMAL Mode
WDT and LVD are all off
IDLEN=0
HALT instruction is executed
SLEEP0 Mode
WDT is on
IDLEN=0
HALT instruction is executed
SLEEP1 Mode
IDLEN=1, FSYSON=0
HALT instruction is executed
IDLE0 Mode
IDLEN=1, FSYSON=1
HALT instruction is executed
IDLE1 Mode
Entering the SLEEP0 Mode
There is only one way for the devices to enter the SLEEP0 Mode and that is to execute the “HALT”
instruction in the application program with the IDLEN bit in the SMOD register equal to “0” and the
WDT and LVD both 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 no matter if the WDT clock source orginates from the
LXT or LIRC oscillator.
• The I/O ports will maintain their present conditions.
• In the status register, the Power Down flag PDF will be set, and WDT timeout flag TO will be
cleared.
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Entering the SLEEP1 Mode
There is only one way for the devices to enter the SLEEP1 Mode and that is to execute the “HALT”
instruction in the application program with the IDLEN bit in the 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 fSUB
clock.
• The Data Memory contents and registers will maintain their present condition.
• The WDT will be cleared and resume counting if the WDT function is enabled.
• The I/O ports will maintain their present conditions.
• In the status register, the Power Down flag PDF will be set, and WDT timeout flag TO will be
cleared.
Entering the IDLE0 Mode
There is only one way for the devices to enter the IDLE0 Mode and that is to execute the “HALT”
instruction in the application program with the IDLEN bit in the SMOD register equal to “1” and
the FSYSON bit in the CTRL 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 fTBC and fSUB clocks 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 function is enabled.
• The I/O ports will maintain their present conditions.
• In the status register, the Power Down flag PDF will be set, and WDT timeout flag TO will be
cleared.
Entering the IDLE1 Mode
There is only one way for the devices to enter the IDLE1 Mode and that is to execute the “HALT”
instruction in the application program with the IDLEN bit in the SMOD register equal to “1” and
the FSYSON bit in the CTRL register equal to “1”. When this instruction is executed under the
conditions described above, the following will occur:
• The system clock, fTBC and fSUB clocks will be on but 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 function is enabled.
• The I/O ports will maintain their present conditions.
• In the status register, the Power Down flag PDF will be set, and WDT timeout flag TO will be
cleared.
Rev. 1.10
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HT66F0175/HT66F0185
A/D 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 devices which have 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. Also note that additional
standby current will also be required if the LIRC oscillator has enabled.
In the IDLE1 Mode the system oscillator is on, if the system oscillator is from the high speed
oscillator, the additional standby current will also be perhaps in the order of several hundred microamps.
Wake-up
To minimise power consumption the device can enter the SLEEP or any IDLE Mode, where the
CPU will be switched off. However, when the device is woken up again, it will take a considerable
time for the original system oscillator to restart, stablise and allow normal operation to resume.
After the system enters the SLEEP or IDLE Mode, it can be woken up from one of various sources
listed as follows:
• An external falling edge on Port A
• A system interrupt
• A WDT overflow
When the devices execute the “HALT” instruction, it will enter the Power down mode and the PDF
flag will be set to 1. The PDF flag will be cleared to 0 if the devices experience a system power-up
or executes the clear Watchdog Timer instruction. If the system is woken up by a WDT overflow, a
Watchdog Timer reset will be initiated and the TO flag will be set to 1. 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, 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 devices 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.
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Programming Considerations
The high speed and low speed oscillators both use the same SST counter. For example, if the system
is woken up from the SLEEP0 Mode and both the HIRC and LXT oscillators need to start-up from
an off state. The LXT oscillator uses the SST counter after the HIRC oscillator has finished its SST
period.
• If the devices are woken up from the SLEEP0 Mode to the NORMAL Mode, the high speed
system oscillator needs an SST period. The devices will execute first instruction after HTO is
“1”. At this time, the LXT oscillator may not be stability if fSUB is from LXT oscillator. The
same situation occurs in the power-on state. The LXT oscillator is not ready yet when the first
instruction is executed.
• If the devices are woken up from the SLEEP1 Mode to NORMAL Mode, and the system clock
source is from the HXT oscillator and FSTEN is “1”, the system clock can be switched to the
LIRC oscillator after wake up.
• There are peripheral functions, such as WDT and TMs, for which the fSYS is used. If the system
clock source is switched from fH to fSUB, the clock source to the peripheral functions mentioned
above will change accordingly.
• The on/off condition of fSUB and fS depends upon whether the WDT is enabled or disabled as the
WDT clock source is selected from fSUB.
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 clock, fSUB, which is in turn supplied
by the LIRC or LXT oscillator. The LXT oscillator is supplied by an external 32.768 kHz crystal.
The LIRC internal oscillator has an approximate frequency of 32 kHz at a supply voltage of
5V. However, it should be noted that this specified internal clock frequency can vary with VDD,
temperature and process variations. The Watchdog Timer source clock is then subdivided by a ratio
of 28 to 218 to give longer timeouts, the actual value being chosen using the WS2~WS0 bits in the
WDTC register.
Watchdog Timer Control Register
A single register, WDTC, controls the required timeout period as well as the enable/disable
operation. This register controls the overall operation of the Watchdog Timer.
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
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 enable control
10101: Disabled
01010: Enabled
Other values: Reset MCU
If these bits are changed due to adverse environmental conditions, the microcontroller
will be reset. The reset operation will be activated after 2~3 LIRC clock cycles and the
WRF bit in the CTRL register will be set to 1.
Bit 2~0WS2~WS0: WDT time-out period selection
000: 28/fSUB
001: 210/fSUB
010: 212/fSUB
011: 214/fSUB
100: 215/fSUB
101: 216/fSUB
110: 217/fSUB
111: 218/fSUB
These three bits determine the division ratio of the watchdog timer source clock,
which in turn determines the time-out period.
CTRL Register
Bit
7
6
5
4
3
2
Name
FSYSON
—
—
R/W
R/W
—
—
POR
0
—
—
—
1
0
—
—
—
—
LVRF
LRF
WRF
R/W
R/W
—
R/W
x
0
0
“x”: unknown
Bit 7FSYSON: fSYS Control in IDLE Mode
Described elsewhere.
Bit 6~3
Unimplemented, read as “0”
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 occurred
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.
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
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 instruction. If the program malfunctions for whatever reason, jumps
to an unknown location, or enters an endless loop, these clear 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 offer the enable/disable control and reset control of the Watchdog Timer. The WDT function will
be disabled when the WE4~WE0 bits are set to a value of 10101B while the WDT function will
be enabled if the WE4~WE0 bits are equal to 01010B. If the WE4~WE0 bits are set to any other
values, except 01010B and 10101B, it will reset the device after 2~3 fLIRC clock cycles. After power
on these bits will have a value of 01010B.
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. Three methods can be adopted to clear the contents of the Watchdog Timer.
The first is a WDT reset, which means a certain value except 01010B and 10101B written into the
WE4~WE0 field, the second is using the Watchdog Timer software clear instruction and the third 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 contents.
The maximum time out period is when the 218 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 8
second for the 218 division ratio and a minimum timeout of 7.8ms for the 28 division ration.
WDTC WE�~WE0 �its
Registe�
Reset MCU
CLR
“HALT”Inst�uction
“CLR WDT”Inst�uction
fSUB
8-stage Divide�
fSUB/�8
WDT P�escale�
WS�~WS0
(fSUB/�8 ~ fSUB/�18)
8-to-1 MUX
WDT Ti�e-out
(�8/fSUB ~ �18/fSUB)
Watchdog timer
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
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, 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. 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.
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.
VDD
Powe�-on Reset
tRSTD
SST Ti�e-out
Note: tRSTD is power-on delay with typical time = 50 ms
Power-On Reset Timing Chart
Low Voltage Reset – LVR
The microcontroller contains a low voltage reset circuit in order to monitor the supply voltage of
the device. The LVR function is always enabled 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 CTRL
register will also be set to 1. For a valid LVR signal, a low supply voltage, i.e., a voltage in the
range between 0.9V~ VLVR must exist for a time greater than that specified by tLVR in the LVD/LVR
characteristics. If the low supply 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 value can be selected by
the LVS bits in the LVRC register. If the LVS7~LVS0 bits have any other value, which may perhaps
occur due to adverse environmental conditions such as noise, the LVR will reset the device after 2~3
fLIRC clock cycles. When this happens, the LRF bit in the CTRL register will be set to 1. After power
on the register will have the value of 01010101B. Note that the LVR function will be automatically
disabled when the device enters the power down mode.
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
LVR
tRSTD + tSST
Inte�nal Reset
Note: tRSTD is power-on delay with typical time = 50 ms
Low Voltage Reset Timing Chart
• 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
0
1
0
1
Bit 7~0LVS7~LVS0: LVR voltage select
01010101: 2.1V
00110011: 2.55V
10011001: 3.15V
10101010: 3.8V
Other values: Generates a MCU reset – register is reset to POR value
When an actual low voltage condition occurs, as specified by one of the four defined
LVR voltage value above, an MCU reset will generated. The reset operation will be
activated after 2~3 fLIRC clock cycles. In this situation the register contents will remain
the same after such a reset occurs.
Any register value, other than the four defined register values above, will also result
in the generation of an MCU reset. The reset operation will be activated after 2~3 fLIRC
clock cycles. However, in this situation the register contents will be reset to the POR
value.
• CTRL Register
Bit
7
6
5
4
3
2
Name
FSYSON
—
—
R/W
R/W
—
—
POR
0
—
—
—
1
0
—
—
—
—
LVRF
LRF
WRF
R/W
R/W
—
R/W
x
0
0
“x”: unknown
Bit 7FSYSON: fSYS Control in IDLE Mode
Described elsewhere.
Bit 6~3
Unimplemented, read as “0”
Bit 2LVRF: LVR function reset flag
0: Not occurred
1: Occurred
This bit is set to 1 when a specific low voltage reset condition occurs. Note that this bit
can only be cleared to 0 by the application program.
Bit 1LRF: LVR control register software reset flag
0: Not occurred
1: Occurred
This bit is set to 1 by the LVRC control register contains any undefined LVR voltage
register values. This in effect acts like a software-reset function. Note that this bit can
only be cleared to 0 by the application program.
Bit 0WRF: WDT control register software reset flag
Described elsewhere.
Rev. 1.10
59
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Watchdog Time-out Reset during Normal Operation
The Watchdog time-out Reset during normal operation is the same as the hardware Low Voltage
Reset except that the Watchdog time-out flag TO will be set to “1”.
WDT Ti�e-out
tRSTD + tSST
Inte�nal Reset
Note: tRSTD is power-on delay with typical time = 16.7 ms
WDT Time-out Reset during NORMAL Operation Timing Chart
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 Ti�e-out
tSST
Inte�nal Reset
WDT Time-out Reset during SLEEP or IDLE Mode 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 Function
u
u
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
“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
Reset Function
Program Counter
Reset to zero
Interrupts
All interrupts will be disabled
WDT, Time Base
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 the microcontroller internal registers. Note that where more
than one package type exists the table will reflect the situation for the larger package type.
Rev. 1.10
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A/D 8-Bit Flash MCU with EEPROM
HT66F0185
HT66F0175
Register
Reset
(Power On)
LVR Reset
(Normal Operation)
WDT Time-out
(Normal Operation)
WDT Time-out
(IDLE or SLEEP)*
MP0
●
●
xxxx xxxx
xxxx xxxx
xxxx xxxx
uuuu uuuu
MP1
●
●
xxxx xxxx
xxxx xxxx
xxxx xxxx
uuuu uuuu
BP
●
●
---- ---0
---- ---0
---- ---0
---- ---u
ACC
●
●
xxxx xxxx
uuuu uuuu
uuuu uuuu
uuuu uuuu
PCL
●
●
0000 0000
0000 0000
0000 0000
0000 0000
uuuu uuuu
TBLP
●
●
xxxx xxxx
uuuu uuuu
uuuu uuuu
TBLH
●
●
xxxx xxxx
uuuu uuuu
uuuu uuuu
uuuu uuuu
TBHP
●
---- -xxx
---- -uuu
---- -uuu
---- -uuu
●
---- xxxx
---- uuuu
---- uuuu
---- uuuu
STATUS
TBHP
●
●
--00 xxxx
--uu uuuu
--1u uuuu
- - 11 u u u u
SMOD
●
●
0 0 0 0 0 0 11
0 0 0 0 0 0 11
0 0 0 0 0 0 11
uuuu uuuu
LVDC
●
●
--00 -000
--00 -000
--00 -000
--uu -uuu
INTEG
●
●
---- 0000
---- 0000
---- 0000
---- uuuu
INTC0
●
-0-0 0-00
-0-0 0-00
-0-0 0-00
-u-u u-uu
●
-000 0000
-000 0000
-000 0000
-uuu uuuu
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
-000 -000
-000 -000
-000 -000
-uuu -uuu
0000 0000
0000 0000
0000 0000
uuuu uuuu
INTC0
INTC1
●
INTC2
●
INTC2
●
MFI0
●
●
--00 --00
--00 --00
--00 --00
--uu --uu
MFI1
●
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
MFI2
●
●
--00 --00
--00 --00
--00 --00
--uu --uu
PA
●
●
1111 1111
1111 1111
1111 1111
uuuu uuuu
PAC
●
●
1111 1111
1111 1111
1111 1111
uuuu uuuu
PAPU
●
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
PAWU
●
●
TMPC
●
TMPC
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
0--- --00
0--- --00
0--- --00
u--- --uu
0--- -000
0--- -000
0--- -000
u--- -uuu
WDTC
●
●
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 0 111
0 0 11 0 111
0 0 11 0 111
uuuu uuuu
CTRL
●
●
0--- -x00
0--- -000
0--- -000
u--- -uuu
LVRC
●
●
0101 0101
0101 0101
0101 0101
uuuu uuuu
EEA
●
--00 0000
--00 0000
--00 0000
--uu uuuu
●
-000 0000
-000 0000
-000 0000
-uuu uuuu
EEA
●
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
SADOL (ADRFS=0) ●
EED
●
xxxx ----
xxxx ----
xxxx ----
uuuu ----
SADOL (ADRFS=1) ●
●
xxxx xxxx
uuuu uuuu
uuuu uuuu
uuuu uuuu
SADOH
(ADRFS=0)
●
●
xxxx xxxx
uuuu uuuu
uuuu uuuu
uuuu uuuu
SADOH
(ADRFS=1)
●
●
---- xxxx
---- uuuu
---- uuuu
---- uuuu
SADC0
●
●
0000 -000
0000 -000
0000 -000
uuuu -uuu
SADC1
●
●
000- -000
000- -000
000- -000
uuu- -uuu
SADC2
●
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
PB
●
●
- 111 1111
- 111 1111
- 111 1111
-uuu uuuu
PBC
●
●
- 111 1111
- 111 1111
- 111 1111
-uuu uuuu
Rev. 1.10
61
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Reset
(Power On)
LVR Reset
(Normal Operation)
WDT Time-out
(Normal Operation)
WDT Time-out
(IDLE or SLEEP)*
●
-000 0000
-000 0000
-000 0000
-uuu uuuu
TM2C0
●
0000 0---
0000 0---
0000 0---
uuuu u---
TM2C1
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM2DL
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM2DH
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM2AL
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM2AH
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM2RP
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
0000 0---
0000 0---
0000 0---
uuuu u---
TM0C0
●
HT66F0185
PBPU
HT66F0175
Register
●
TM0C1
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM0DL
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM0DH
●
----- --00
---- --00
---- --00
---- --uu
uuuu uuuu
TM0AL
●
0000 0000
0000 0000
0000 0000
TM0AH
●
----- --00
---- --00
---- --00
---- --uu
TM0RPL
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM0RPH
●
----- --00
---- --00
---- --00
---- --uu
0000 0---
0000 0---
0000 0---
uuuu u---
TM0C0
●
TM0C1
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM0DL
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM0DH
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM0AL
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM0AH
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM0RP
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM1C0
●
●
0000 0---
0000 0---
0000 0---
uuuu u---
TM1C1
●
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM1DL
●
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM1DH
●
●
----- --00
---- --00
---- --00
---- --uu
uuuu uuuu
TM1AL
●
●
0000 0000
0000 0000
0000 0000
TM1AH
●
●
----- --00
---- --00
---- --00
---- --uu
TM1RPL
●
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM1RPH
●
●
----- --00
---- --00
---- --00
---- --uu
●
1000 0001
1000 0001
1000 0001
uuuu uuuu
CPC
PC
●
●
- 111 1111
- 111 1111
- 111 1111
-uuu uuuu
PCC
●
●
- 111 1111
- 111 1111
- 111 1111
-uuu uuuu
PCPU
●
●
-000 0000
-000 0000
-000 0000
-uuu uuuu
ACERL
●
●
1111 1111
1111 1111
1111 1111
uuuu uuuu
SIMC0
●
●
111 - 0 0 0 0
111 - 0 0 0 0
111 - 0 0 0 0
uuu- uuuu
SIMC1
●
●
1000 0001
1000 0001
1000 0001
uuuu uuuu
SIMD
●
●
xxxx xxxx
xxxx xxxx
xxxx xxxx
uuuu uuuu
SIMA/SIMC2
●
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
SIMTOC
●
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
SLCDC0
●
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
SLCDC1
●
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
SLCDC2
●
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
●
SLCDC4
SLEDC0
●
SLEDC1
HT66F0185
SLCDC3
HT66F0175
Register
Reset
(Power On)
LVR Reset
(Normal Operation)
WDT Time-out
(Normal Operation)
WDT Time-out
(IDLE or SLEEP)*
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
●
---- --00
---- --00
---- --00
---- --uu
●
0101 0101
0101 0101
0101 0101
uuuu uuuu
●
--01 0101
--01 0101
--01 0101
--uu uuuu
---- uuuu
SLEDC1
●
---- 0101
---- 0101
---- 0101
IFS
●
--00 0000
--00 0000
--00 0000
--uu uuuu
-000 0000
-000 0000
-000 0000
-uuu uuuu
IFS
●
PD
●
- - - - 1111
- - - - 1111
- - - - 1111
---- uuuu
PDC
●
- - - - 1111
- - - - 1111
- - - - 1111
---- uuuu
PDPU
●
---- 0000
---- 0000
---- 0000
---- uuuu
USR
●
0 0 0 0 1 0 11
0 0 0 0 1 0 11
0 0 0 0 1 0 11
uuuu uuuu
UCR1
●
0000 00x0
0000 00x0
0000 00x0
uuuu uuuu
UCR2
●
0000 0000
0000 0000
0000 0000
uuuu uuuu
BRG
●
xxxx xxxx
xxxx xxxx
xxxx xxxx
uuuu uuuu
TXR_RXR
EEC
●
●
xxxx xxxx
xxxx xxxx
xxxx xxxx
uuuu uuuu
●
---- 0000
---- 0000
---- 0000
---- uuuu
Note: “u” stands for unchanged
“x” stands for “unknown”
“-“ stands for unimplemented
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
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.
These devices provide bidirectional input/output lines labeled with port names PA~PD. 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.
Bit
Register
Name
7
6
5
4
3
2
1
0
PAWU
PAWU7
PAWU6
PAWU5
PAWU4
PAWU3
PAWU2
PAWU1
PAWU0
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
PB
—
PB6
PB5
PB4
PB3
PB2
PB1
PB0
PBC
—
PBC6
PBC5
PBC4
PBC3
PBC2
PBC1
PBC0
PBPU
—
PBPU6
PBPU5
PBPU4
PBPU3
PBPU2
PBPU1
PBPU0
PC
—
PC6
PC5
PC4
PC3
PC2
PC1
PC0
PCC
—
PCC6
PCC5
PCC4
PCC3
PCC2
PCC1
PCC0
PCPU
—
PCPU6
PCPU5
PCPU4
PCPU3
PCPU2
PCPU1
PCPU0
I/O Registers List – HT66F0175
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Bit
Register
Name
7
6
5
4
3
2
1
0
PAWU
PAWU7
PAWU6
PAWU5
PAWU4
PAWU3
PAWU2
PAWU1
PAWU0
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
PB
—
PB6
PB5
PB4
PB3
PB2
PB1
PB0
PBC
—
PBC6
PBC5
PBC4
PBC3
PBC2
PBC1
PBC0
PBPU
—
PBPU6
PBPU5
PBPU4
PBPU3
PBPU2
PBPU1
PBPU0
PC
—
PC6
PC5
PC4
PC3
PC2
PC1
PC0
PCC
—
PCC6
PCC5
PCC4
PCC3
PCC2
PCC1
PCC0
PCPU
—
PCPU6
PCPU5
PCPU4
PCPU3
PCPU2
PCPU1
PCPU0
PD
—
—
—
—
PD3
PD2
PD1
PD0
PDC
—
—
—
—
PDC3
PDC2
PDC1
PDC0
PDPU
—
—
—
—
PDPU3
PDPU2
PDPU1
PDPU0
I/O Registers List – HT66F0185
“—”: Unimplemented, read as “0”.
PAWUn: Port A Pin wake-up function control
0: Disable
1: Enable
PAPUn/PBPUn/PCPUn/PDPUn: I/O Pin pull-high function control
0: Disable
1: Enable
PAn/PBn/PCn/PDn: I/O Port Data bit
0: Data 0
1: Data 1
PACn/PBCn/PCCn/PDCn: I/O Pin type selection
0: Output
1: Input
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 the relevant pull-high control registers and are implemented
using weak PMOS transistors.
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.
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A/D 8-Bit Flash MCU with EEPROM
I/O Port Control Registers
Each Port has its own control register, known as PAC~PDC, which controls the input/output
configuration. With this control register, each I/O pin with or without pull-high resistors can be
reconfigured dynamically under software control. 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.
I/O Port Source Current Control
These devices support different source current driving capability for each I/O port. With the
corresponding selection register, SLEDC0 and SLEDC1, each I/O port can support four levels of the
source current driving capability. Users should refer to the D.C. characteristics section to select the
desired source current for different applications.
Bit
Register
Name
7
6
5
4
3
2
1
0
PBPS3
PBPS2
PBPS1
PBPS0
PAPS3
PAPS2
PAPS1
PAPS0
SLEDC1
(HT66F0175)
—
—
—
—
PCPS3
PCPS2
PCPS1
PCPS0
SLEDC1
(HT66F0185)
—
—
PDPS1
PDPS0
PCPS3
PCPS2
PCPS1
PCPS0
SLEDC0
I/O Port Source Current Control Registers List
SLEDC0 Register
Bit
7
6
5
4
3
2
1
0
Name
PBPS3
PBPS2
PBPS1
PBPS0
PAPS3
PAPS2
PAPS1
PAPS0
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 7~6PBPS3~PBPS2: PB6~PB4 source current selection
00: source current = Level 0 (min.)
01: source current = Level 1
10: source current = Level 2
11: source current = Level 3 (max.)
Bit 5~4PBPS1~PBPS0: PB3~PB0 source current selection
00: source current = Level 0 (min.)
01: source current = Level 1
10: source current = Level 2
11: source current = Level 3 (max.)
Bit 3~2PAPS3~PAPS2: PA7~PA4 source current selection
00: source current = Level 0 (min.)
01: source current = Level 1
10: source current = Level 2
11: source current = Level 3 (max.)
Bit 1~0PAPS1~PAPS0: PA3~PA0 source current selection
00: source current = Level 0 (min.)
01: source current = Level 1
10: source current = Level 2
11: source current = Level 3 (max.)
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
SLEDC1 Register – HT66F0175
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
PCPS3
PCPS2
PCPS1
PCPS0
R/W
—
—
—
—
R/W
R/W
R/W
R/W
POR
—
—
—
—
0
1
0
1
Bit 7~4
Unimplemented, read as “0”
Bit 3~2PCPS3~PCPS2: PC6~PC4 source current selection
00: source current = Level 0 (min.)
01: source current = Level 1
10: source current = Level 2
11: source current = Level 3 (max.)
Bit 1~0PCPS1~PCPS0: PC3~PC0 source current selection
00: source current = Level 0 (min.)
01: source current = Level 1
10: source current = Level 2
11: source current = Level 3 (max.)
SLEDC1 Register – HT66F0185
Bit
7
6
5
4
3
2
1
0
Name
—
—
PDPS1
PDPS0
PCPS3
PCPS2
PCPS1
PCPS0
R/W
—
—
R/W
R/W
R/W
R/W
R/W
R/W
POR
—
—
0
1
0
1
0
1
Bit 7~6
Unimplemented, read as “0”
Bit 5~4PDPS1~PDPS0: PD3~PD0 source current selection
00: source current = Level 0 (min.)
01: source current = Level 1
10: source current = Level 2
11: source current = Level 3 (max.)
Bit 3~2PCPS3~PCPS2: PC6~PC4 source current selection
00: source current = Level 0 (min.)
01: source current = Level 1
10: source current = Level 2
11: source current = Level 3 (max.)
Bit 1~0PCPS1~PCPS0: PC3~PC0 source current selection
00: source current = Level 0 (min.)
01: source current = Level 1
10: source current = Level 2
11: source current = Level 3 (max.)
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Pin-remapping 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. The way in
which the pin function of each pin is selected is different for each function and a priority order is
established where more than one pin function is selected simultaneously. Additionally there is a
register, IFS, to establish certain pin functions.
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. If the pin-shared pin function have multiple outputs
simultaneously, its pin names at the right side of the “/” sign can be used for higher priority.
Bit
Register
Name
7
6
5
IFS
(HT66F0175)
4
—
—
SDOPS
IFS
(HT66F0185)
—
3
2
1
0
SDI_SDAPS SCK_SCLPS SCSBPS INT1PS INT0PS
SDOPS1 SDOPS0 SDI_SDAPS SCK_SCLPS SCSBPS
TXPS
RXPS
Pin-remapping Function Selection Registers List
IFS Register – HT66F0175
Bit
7
6
5
Name
—
—
SDOPS
R/W
—
—
R/W
R/W
R/W
R/W
POR
—
—
0
0
0
0
Bit 7~6
4
3
2
SDI_SDAPS SCK_SCLPS SCSBPS
1
0
INT1PS
INT0PS
R/W
R/W
0
0
Unimplemented, read as “0”
Bit 5SDOPS: SDO pin-remapping selection
0: SDO on PC2
1: SDO on PA1
Bit 4SDI_SDAPS: SDI/SDA pin-remapping selection
0: SDI/SDA on PC3
1: SDI/SDA on PA3
Bit 3SCK_SCLPS: SCK/SCL pin-remapping selection
0: SCK/CL on PC4
1: SCK/CL on PB6
Bit 2SCSBPS: SCS pin-remapping selection
0: SCS on PA1
1: SCS on PB5
Bit 1INT1PS: INT1 pin-remapping selection
0: INT1 on PB1
1: INT1 on PC5
Bit 0INT0PS: INT0 pin-remapping selection
0: INT0 on PB0
1: INT0 on PC6
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
IFS Register – HT66F0185
Bit
7
Name
—
6
5
4
3
2
SDOPS1 SDOPS0 SDI_SDAPS SCK_SCLPS SCSBPS
1
0
TXPS
RXPS
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 6~5SDOPS1~SDOPS0: SDO pin-remapping selection
00: SDO on PC3
01: SDO on PA1
10: Undefined
11: SDO on PC2
Bit 4SDI_SDAPS: SDI/SDA pin-remapping selection
0: SDI/SDA on PC4
1: SDI/SDA on PA3
Bit 3SCK_SCLPS: SCK/SCL pin-remapping selection
0: SCK/CL on PC5
1: SCK/CL on PB6
Bit 2SCSBPS: SCS pin-remapping selection
0: SCS on PC6
1: SCS on PB5
Bit 1TXPS: TX pin-remapping selection
0: TX on PD2
1: TX on PB3
Bit 0RXPS: RX pin-remapping selection
0: RX on PD1
1: RX on PB4
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. 1.10
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November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
ƒ ­ €
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A/D Input/Output Structure
Programming Considerations
Within the user program, one of the things first to consider is port initialisation. After a reset, all
of the I/O data and port control registers will be set to high. This means that all I/O pins will be
defaulted to an input state, the level of which depends on the other connected circuitry and whether
pull-high 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.
The power-on reset condition of the A/D converter control registers ensures that any A/D input
pins, which are always shared with other I/O functions, will be setup as analog inputs after a reset.
Although these pins will be configured as A/D inputs after a reset, the A/D converter will not be
switched on. It is therefore important to note that if it is required to use these pins as I/O digital
input pins or as other functions, the A/D converter control registers must be correctly programmed
to remove the A/D function. Note also that as the A/D channel is enabled, any internal pull-high
resistor connections will be removed.
Port A has the additional capability of providing wake-up functions. When the devices are in the
SLEEP or IDLE Mode, various methods are available to wake the devices 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. 1.10
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A/D 8-Bit Flash MCU with EEPROM
Timer Modules – TM
One of the most fundamental functions in any microcontroller devices is the ability to control and
measure time. To implement time related functions each device includes several Timer Modules,
generally 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
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 Compact, Standard and Periodic TM sections.
Introduction
The devices contain two or three TMs depending upon which device is selected with each TM
having a reference name of TM0, TM1, and TM2. Each individual TM can be categorised as a
certain type, namely Compact Type TM, Standard Type TM or Periodic Type TM. Although similar
in nature, the different TM types vary in their feature complexity. The common features to all of the
Compact, Standard and Periodic TMs will be described in this section and the detailed operation
regarding each of the TM types will be described in separate sections. The main features and
differences between the three types of TMs are summarised in the accompanying table.
CTM
STM
PTM
Timer/Counter
TM Function
√
√
√
Input Capture
—
√
√
Compare Match Output
√
√
√
PWM Channels
1
1
1
Single Pulse Output
—
1
1
PWM Alignment
PWM Adjustment Period & Duty
Edge
Edge
Edge
Duty or Period
Duty or Period
Duty or Period
TM Function Summary
Each device in the series contains a specific number of either Compact Type, Standard Type and
Periodic Type TM units which are shown in the table together with their individual reference name,
TM0~TM2.
Device
TM0
TM1
HT66F0175
10-bit PTM
10-bit PTM
TM2
—
HT66F0185
16-bit STM
10-bit PTM
16-bit CTM
TM Name/Type Reference
TM Operation
The 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 count-up counter whose value is then compared with the value of pre-programmed internal
comparators. When the free running count-up 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.
Rev. 1.10
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A/D 8-Bit Flash MCU with EEPROM
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 TnCK2~TnCK0 bits in the TM
control registers. The clock source can be a ratio of the system clock, fSYS, or the internal high clock,
fH, the fTBC clock source or the external TCKn pin. The TCKn pin clock source is used to allow an
external signal to drive the TM as an external clock source for event counting.
TM Interrupts
The Compact, Standard or Periodic type TM has two internal interrupts, one for each of 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 one TM input pin, with the label TCKn. The TM
input pin is essentially a clock source for the TM and is selected using the TnCK2~TnCK0 bits in
the TMnC0 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 TnCK2~TnCK0 bits. The TM input pin can be chosen to have either a
rising or falling active edge. The TCKn pin is also used as the external trigger input pin in single
pulse output mode for the STM and PTM respectively.
The TMs each have one output pin with the label TPn. 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 TPn output pin is also the pin where the
TM generates the PWM output waveform. The TPn pin acts as an input when the TM is setup to
operate in the Capture Input Mode. As the TPn pins are pin-shared with other functions, the TPn
pin function is enabled or disabled according to the internal TM on/off control, operation mode and
output control settings. When the corresponding TM configuration selects the TPn pin to be used as
an output pin, the associated pin will be setup as an external TM output pin. If the TM configuration
selects the TPn pin to be setup as an input pin, the input signal supplied on the associated pin can
be derived from an external signal and other pin-shared output function. If the TM configuration
determines that the TPn pin function is not used, the associated pin will be controlled by other
pin-shared functions. The details of the TPn pin for each TM type and device are provided in the
accompanying table.
Device
STM
PTM
CTM
Register
HT66F0175
—
TCK0; TP0
TCK1; TP1
—
TMPC
HT66F0185
TCK0; TP0
TCK1; TP1
TCK2; TP2
TMPC
TM External Pins
Rev. 1.10
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A/D 8-Bit Flash MCU with EEPROM
TM Input/Output Pin Control Register
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.
Register Name
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
TMPC (HT66F0175)
CLOP
—
—
—
—
—
T1CP
T0CP
TMPC (HT66F0185)
CLOP
—
—
—
—
T2CP
T1CP
T0CP
TM Pin Control Register List
PA0 Output Function
0
1
PA0/TP0
0
Output
1
T0CP
PA0
TM0
(PTM)
Captu�e Input
1
0
0
1
T0CAPTS
TCK Input
PB�/TCK0
TM0 Function Pin Control Block Diagram – HT66F0175 only
PA0 Output Function
0
1
PA0/TP0
0
Output
1
TM0
(STM)
T0CP
PA0
Captu�e Input
1
0
TCK Input
PB�/TCK0
TM0 Function Pin Control Block Diagram – HT66F0185 only
PA7 Output Function
0
1
PA7/TP1
0
Output
1
T1CP
PA7
TM1
(PTM)
Captu�e Input
0
1
1
0
T1CAPTS
TCK Input
PA�/TCK1
TM1 Function Pin Control Block Diagram – HT66F0175/HT66F0185
Rev. 1.10
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November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
PB3 Output Function
0
1
TM2
(CTM)
PB3/TP�
0
Output
1
T�CP
PB3
TCK Input
PA6/TCK�
TM2 Function Pin Control Block Diagram – HT66F0185 only
Note: 1. The I/O register data bits shown are used for TM output inversion control.
2. In the Capture Input Mode, the TM pin control register must never enable more than one
TM input.
TMPC Register – HT66F0175
Bit
7
6
5
4
3
2
1
0
Name
CLOP
—
—
—
R/W
R/W
—
—
—
—
—
T1CP
T0CP
—
—
R/W
POR
0
—
—
—
—
R/W
—
0
0
Bit 7CLOP: CLO pin control
0: Disable
1: Enable
Bit 6~2
Unimplemented, read as “0”
Bit 1T1CP: TP1 pin control
0: Disable
1: Enable
Bit 0T0CP: TP0 pin control
0: Disable
1: Enable
TMPC Register – HT66F0185
Bit
7
6
5
4
3
2
1
0
Name
CLOP
—
—
—
—
T2CP
T1CP
T0CP
R/W
R/W
—
—
—
—
R/W
R/W
R/W
POR
0
—
—
—
—
0
0
0
Bit 7CLOP: CLO pin control
0: Disable
1: Enable
Bit 6~3
Unimplemented, read as “0”
Bit 2T2CP: TP2 pin control
0: Disable
1: Enable
Bit 1T1CP: TP1 pin control
0: Disable
1: Enable
Bit 0T0CP: TP0 pin control
0: Disable
1: Enable
Rev. 1.10
74
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Programming Considerations
The TM Counter Registers and the Capture/Compare CCRA and CCRP registers, being either 10bit or 16-bit, 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 and CCRP registers are implemented in the way shown in the following diagram and
accessing these register pairs is carried out in a specific way as described above, it is recommended
to use the “MOV” instruction to access the CCRA and CCRP low byte registers, named TMnAL and
TMnRPL, using the following access procedures. Accessing the CCRA or CCRP low byte registers
without following these access procedures will result in unpredictable values.
TMn Counte� Registe� (Read only)
TMnDL
TMnDH
8-�it Buffe�
TMnAL
TMnAH
TMn CCRA Registe� (Read/W�ite)
TMnRPL
TMnRPH
PTM CCRP Registe� (Read/W�ite)
Data Bus
The following steps show the read and write procedures:
• Writing Data to CCRA or CCRP
♦♦
Step 1. Write data to Low Byte TMnAL or TMnRPL
––note that here data is only written to the 8-bit buffer.
♦♦
Step 2. Write data to High Byte TMnAH or TMnRPH
––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 CCRP
Rev. 1.10
♦♦
Step 1. Read data from the High Byte TMnDH, TMnAH or TMnRPH
––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 TMnDL, TMnAL or TMnRPL
––this step reads data from the 8-bit buffer.
75
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Compact Type TM – CTM
The Compact type TM, CTM, is only contained in the HT66F0185 device. Although the simplest
form of the TM types, the Compact TM type still contains three operating modes, which are
Compare Match Output, Timer/Event Counter and PWM Output modes. The Compact TM can also
be controlled with an external input pin and can drive one external output pin.
Device
TM Core
TM No.
TM Input Pin
TM Output Pin
HT66F0185
16-bit CTM
TM2
TCK2
TP2
CCRP
fSYS/�
fSYS
fH/16
fH/6�
fTBC
fH/8
001
�8~�15
011
101
111
Counte� Clea�
16-�it Count-up Counte�
100
TnO�
TnPAU
0
1
TnCCLR
�0~�15
16-�it Co�pa�ato� A
TnPF Inte��upt
TnOC
010
110
TCKn
Co�pa�ato� P Match
8-�it Co�pa�ato� P
000
Co�pa�ato� A Match
Output
Cont�ol
Pola�ity
Cont�ol
Pin
Cont�ol
TnM1� TnM0
TnIO1� TnIO0
TnPOL
TnCP
TPn
TnAF Inte��upt
TnCK�~TnCK0
CCRA
Compact Type TM Block Diagram – n = 2 for HT66F0185 only
Compact TM Operation
The Compact TM core is a 16-bit count-up counter which is driven by a user selectable internal or
external 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 eight-bit wide whose value is compared with the highest eight bits in the
counter while the CCRA is sixteen-bit wide and therefore compares with all counter bits.
The only way of changing the value of the 16-bit counter using the application program, is to
clear the counter by changing the TnON 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 Compact
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 an output pin. All operating setup conditions are
selected using relevant internal registers.
Rev. 1.10
76
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Compact Type TM Register Description
Overall operation of the Compact TM is controlled using a series of registers. A read only register
pair exists to store the internal counter 16-bit value, while a read/write register pair exists to store
the internal 16-bit CCRA value. There is also a read/write register used to store the internal 8-bit
CCRP value. The remaining two registers are control registers which setup the different operating
and control modes.
Register
Name
Bit7
Bit6
Bit5
Bit4
TMnC0
TnPAU
TnCK2
TnCK1
TnCK0
TnON
—
—
—
TMnC1
TnM1
TnM0
TnIO1
TnIO0
TnOC
TnPOL
TnDPX
TnCCLR
Bit3
Bit2
Bit1
Bit0
TMnDL
D7
D6
D5
D4
D3
D2
D1
D0
TMnDH
D15
D14
D13
D12
D11
D10
D9
D8
TMnAL
D7
D6
D5
D4
D3
D2
D1
D0
TMnAH
D15
D14
D13
D12
D11
D10
D9
D8
TMnRP
TnRP7
TnRP6
TnRP5
TnRP4
TnRP3
TnRP2
TnRP1
TnRP0
16-bit Compact TM Registers List – n = 2 for for HT66F0185 only
TMnDL 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
TMn Counter Low Byte Register bit 7 ~ bit 0
TMn 16-bit Counter bit 7 ~ bit 0
TMnDH Register
Bit
7
6
5
4
3
2
1
0
Name
D15
D14
D13
D12
D11
D10
D9
D8
R/W
R
R
R
R
R
R
R
R
POR
0
0
0
0
0
0
0
0
Bit 7~0
TMn Counter High Byte Register bit 7 ~ bit 0
TMn 16-bit Counter bit 15 ~ bit 8
TMnAL 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
3
2
1
0
Bit 7~0
TMn CCRA Low Byte Register bit 7 ~ bit 0
TMn 16-bit CCRA bit 7 ~ bit 0
TMnAH Register
Bit
6
5
4
Name
D15
D14
D13
D12
D11
D10
D9
D8
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
Rev. 1.10
7
TMn CCRA High Byte Register bit 7 ~ bit 0
TMn 16-bit CCRA bit 15 ~ bit 8
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November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
TMnC0 Register
Bit
7
6
5
4
3
2
1
0
Name
TnPAU
TnCK2
TnCK1
TnCK0
TnON
—
—
—
R/W
R/W
R/W
R/W
R/W
R/W
—
—
—
POR
0
0
0
0
0
—
—
—
Bit 7TnPAU: TMn 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 TMn 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 6~4TnCK2~TnCK0: Select TMn Counter clock
000: fSYS/4
001: fSYS
010: fH/16
011: fH/64
100: fTBC
101: fH/8
110: TCKn rising edge clock
111: TCKn falling edge clock
These three bits are used to select the clock source for the TMn. 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 3TnON: TMn Counter On/Off control
0: Off
1: On
This bit controls the overall on/off function of the TMn. Setting the bit high enables
the counter to run while clearing the bit disables the TMn. Clearing this bit to zero
will stop the counter from counting and turn off the TMn 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 TMn is in
the Compare Match Output Mode then the TMn output pin will be reset to its initial
condition, as specified by the TnOC bit, when the TnON bit changes from low to high.
Bit 2~0
Rev. 1.10
Unimplemented, read as “0”
78
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
TMnC1 Register
Bit
7
6
5
4
3
2
1
0
Name
TnM1
TnM0
TnIO1
TnIO0
TnOC
TnPOL
TnDPX
TnCCLR
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 7~6TnM1~TnM0: Select TMn Operating Mode
00: Compare Match Output Mode
01: Undefined
10: PWM Mode
11: Timer/Counter Mode
These bits setup the required operating mode for the TMn. To ensure reliable operation
the TMn should be switched off before any changes are made to the TnM1 and TnM0
bits. In the Timer/Counter Mode, the TMn output pin control will be disabled.
Bit 5~4TnIO1~TnIO0: Select TPn pin output function
Compare Match Output Mode
00: No change
01: Output low
10: Output high
11: Toggle output
PWM Output Mode
00: PWM output inactive state
01: PWM output active state
10: PWM output
11: Undefined
Timer/Counter Mode
Unused
These two bits are used to determine how the TMn output pin changes state when a
certain condition is reached. The function that these bits select depends upon in which
mode the TMn is running.
In the Compare Match Output Mode, the TnIO1 and TnIO0 bits determine how the
TMn output pin changes state when a compare match occurs from the Comparator A.
The TMn 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 bits are both
zero, then no change will take place on the output. The initial value of the TMn output
pin should be setup using the TnOC bit in the TMnC1 register. Note that the output
level requested by the TnIO1 and TnIO0 bits must be different from the initial value
setup using the TnOC bit otherwise no change will occur on the TMn output pin when
a compare match occurs. After the TMn output pin changes state, it can be reset to its
initial level by changing the level of the TnON bit from low to high.
In the PWM Mode, the TnIO1 and TnIO0 bits determine how the TMn 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 only change the
values of the TnIO1 and TnIO0 bits only after the TMn has been switched off.
Unpredictable PWM outputs will occur if the TnIO1 and TnIO0 bits are changed when
the TMn is running.
Rev. 1.10
79
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Bit 3TnOC: TPn Output control
Compare Match Output Mode
0: Initial low
1: Initial high
PWM Output Mode
0: Active low
1: Active high
This is the output control bit for the TMn output pin. Its operation depends upon
whether TMn is being used in the Compare Match Output Mode or in the PWM Mode.
It has no effect if the TMn is in the Timer/Counter Mode. In the Compare Match
Output Mode it determines the logic level of the TMn output pin before a compare
match occurs. In the PWM Mode it determines if the PWM signal is active high or
active low.
Bit 2TnPOL: TPn Output polarity control
0: Non-inverted
1: Inverted
This bit controls the polarity of the TPn output pin. When the bit is set high the TMn
output pin will be inverted and not inverted when the bit is zero. It has no effect if the
TMn is in the Timer/Counter Mode.
Bit 1TnDPX: TMn PWM duty/period 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 0TnCCLR: TMn Counter Clear condition selection
0: TMn Comparator P match
1: TMn Comparator A match
This bit is used to select the method which clears the counter. Remember that the
Compact TM contains two comparators, Comparator A and Comparator P, either of
which can be selected to clear the internal counter. With the TnCCLR 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 TnCCLR bit is not
used in the PWM Mode.
TMnRP Register
Bit
7
6
5
4
3
2
1
0
Name
TnRP7
TnRP6
TnRP5
TnRP4
TnRP3
TnRP2
TnRP1
TnRP0
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 7~0TnRP7~TnRP0: TMn CCRP 8-bit register, compared with the TMn Counter bit 15~bit 8
Comprartor P Match Period
0: 65535 TMn clocks
1~255: 256 × (1~255) TMn clocks
These eight bits are used to setup the value on the internal CCRP 8-bit register, which
are then compared with the internal counter’s highest eight bits. The result of this
comparison can be selected to clear the internal counter if the TnCCLR bit is set to
zero. Setting the TnCCLR 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 eight counter bits, the compare values exist in 256 clock cycle multiples.
Clearing all three bits to zero is in effect allowing the counter to overflow at its
maximum value.
Rev. 1.10
80
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Compact Type TM Operation Modes
The Compact Type TM can operate in one of three operating modes, Compare Match Output Mode,
PWM Mode or Timer/Counter Mode. The operating mode is selected using the TnM1 and TnM0
bits in the TMnC1 register.
Compare Match Output Mode
To select this mode, bits TnM1 and TnM0 in the TMnC1 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 TnCCLR 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 TnAF and TnPF interrupt request flags for the Comparator
A and Comparator P respectively, will both be generated.
If the TnCCLR bit in the TMnC1 register is high then the counter will be cleared when a compare
match occurs from Comparator A. However, here only the TnAF interrupt request flag will be
generated even if the value of the CCRP bits is less than that of the CCRA registers. Therefore when
TnCCLR is high no TMnPF interrupt request flag will be generated. If the CCRA bits are all zero,
the counter will overflow when its reaches its maximum 1-bit, FFFF Hex, value, however here the
TnAF interrupt request flag will not be generated.
As the name of the mode suggests, after a comparison is made, the TMn output pin will change
state. The TMn output pin condition however only changes state when a TnAF interrupt request
flag is generated after a compare match occurs from Comparator A. The TnPF interrupt request flag,
generated from a compare match occurs from Comparator P, will have no effect on the TMn output
pin. The way in which the TMn output pin changes state are determined by the condition of the
TnIO1 and TnIO0 bits in the TMnC1 register. The TMn output pin can be selected using the TnIO1
and TnIO0 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 TMn output pin, which is setup after the
TnON bit changes from low to high, is setup using the TnOC bit. Note that if the TnIO1 and TnIO0
bits are zero then no pin change will take place.
Rev. 1.10
81
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Counter Value
Counter overflow
CCRP=0
0xFFFF
TnCCLR = 0; TnM [1:0] = 00
CCRP > 0
Counter cleared by CCRP value
CCRP > 0
Counter
Restart
Resume
CCRP
Pause
CCRA
Stop
Time
TnON
TnPAU
TnPOL
CCRP Int. flag
TnPF
CCRA Int. flag
TnAF
TMn O/P Pin
Output pin set to
initial Level Low
if TnOC=0
Output not affected by TnAF
flag. Remains High until reset by
TnON bit
Output Toggle with
TnAF flag
Here TnIO [1:0] = 11
Toggle Output select
Note TnIO [1:0] = 10
Active High Output select
Output Inverts
when TnPOL is high
Output Pin
Reset to Initial value
Output controlled by
other pin-shared function
Compare Match Output Mode – TnCCLR = 0
Note: 1. With TnCCLR = 0, a Comparator P match will clear the counter
2. The TMn output pin controlled only by TnAF flag
3. The output pin is reset to its initial state by TnON bit rising edge
4. n = 2 for HT66F0185 only
Rev. 1.10
82
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Counter Value
TnCCLR = 1; TnM [1:0] = 00
CCRA = 0
Counter overflow
CCRA > 0 Counter cleared by CCRA value
0xFFFF
Resume
CCRA
Pause
CCRA=0
Stop
Counter Restart
CCRP
Time
TnON
TnPAU
TnPOL
No TnAF flag
generated on
CCRA overflow
CCRA Int. flag
TnAF
CCRP Int. flag
TnPF
TMn O/P Pin
TnPF not
generated
Output pin set to
initial Level Low
if TnOC=0
Output does
not change
Output not affected by TnAF
flag. Remains High until
reset by TnON bit
Output Toggle with
TnAF flag
Here TnIO [1:0] = 11
Toggle Output select
Note TnIO [1:0] = 10
Active High Output select
Output Inverts
when TnPOL is high
Output Pin
Reset to Initial value
Output controlled by
other pin-shared function
Compare Match Output Mode – TnCCLR = 1
Note: 1. With TnCCLR = 1, a Comparator A match will clear the counter
2. The TMn output pin is controlled only by TnAF flag
3. The TMn output pin is reset to initial state by TnON rising edge
4. The TnPF flags is not generated when TnCCLR = 1
5. n = 2 for HT66F0185 only
Rev. 1.10
83
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Timer/Counter Mode
To select this mode, bits TnM1 and TnM0 in the TMnC1 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 TMn 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 TMn 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 TnM1 and TnM0 in the TMnC1 register should be set to 10 respectively.
The PWM function within the TMn 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 TMn 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 TnCCLR bit has no effect on the PWM
operation. 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 TnDPX bit in the TMnC1 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 TnOC bit in the TMnC1 register is used to
select the required polarity of the PWM waveform while the two TnIO1 and TnIO0 bits are used to
enable the PWM output or to force the TM output pin to a fixed high or low level. The TnPOL bit is
used to reverse the polarity of the PWM output waveform.
• 16-bit CTM, PWM Mode, Edge-aligned Mode, TnDPX=0
CCRP
1~255
0
Period
CCRP × 256
65536
Duty
CCRA
If fSYS = 16MHz, TMn clock source is fSYS/4, CCRP = 2 and CCRA = 128,
The TMn PWM output frequency = (fSYS/4) / (2×256) = fSYS/2048 = 7.8125 kHz, duty = 128/(2×256)=
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%.
• 16-bit CTM, PWM Mode, Edge-aligned Mode, TnDPX=1
CCRP
1~255
Period
0
CCRA
CCRP × 256
Duty
65536
The PWM output period is determined by the CCRA register value together with the TMn clock
while the PWM duty cycle is defined by the (CCRP×256) value except when the CCRP value is
equal to 0.
Rev. 1.10
84
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Counter Value
TnDPX = 0; TnM [1:0] = 10
Counter cleared
by CCRP
Counter Reset when
TnON returns high
CCRP
Pause Resume
CCRA
Counter Stop if
TnON bit low
Time
TnON
TnPAU
TnPOL
CCRA Int. flag
TnAF
CCRP Int. flag
TnPF
TMn O/P Pin
(TnOC=1)
TMn O/P Pin
(TnOC=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 TnPOL = 1
PWM Output Mode – TnDPX = 0
Note: 1. Here TnDPX = 0 – Counter cleared by CCRP
2. A counter clear sets PWM Period
3. The internal PWM function continues even when TnIO [1:0] = 00 or 01
4. The TnCCLR bit has no influence on PWM operation
5. n = 2 for HT66F0185 only
Rev. 1.10
85
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Counter Value
TnDPX = 1; TnM [1:0] = 10
Counter cleared
by CCRA
Counter Reset when
TnON returns high
CCRA
Pause Resume
CCRP
Counter Stop if
TnON bit low
Time
TnON
TnPAU
TnPOL
CCRP Int.
flag TnPF
CCRA Int.
flag TnAF
TMn O/P Pin
(TnOC=1)
TMn O/P Pin
(TnOC=0)
PWM Duty Cycle
set by CCRP
PWM Period
set by CCRA
PWM resumes
operation
Output controlled by
Output Inverts
other pin-shared function
when TnPOL = 1
PWM Output Mode – TnDPX = 1
Note: 1. Here TnDPX = 1 – Counter cleared by CCRA
2. A counter clear sets PWM Period
3. The internal PWM function continues even when TnIO [1:0] = 00 or 01
4. The TnCCLR bit has no influence on PWM operation
5. n = 2 for HT66F0185 only
Rev. 1.10
86
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Standard Type TM – STM
The Standard Type TM, STM, is only contained in the HT66F0185 device. 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 also be controlled with
an external input pin and can drive one external output pin.
Device
TM Core
TM No.
TM Input Pin
TM Output Pin
HT66F0185
16-bit STM
TM0
TCK0
TP0
CCRP
fSYS/�
fSYS
fH/16
fH/6�
fTBC
fH/8
001
�8~�15
011
101
Counte� Clea� 0
16-�it Count-up Counte�
100
TnO�
TnPAU
111
1
TnCCLR
�0~�15
16-�it Co�pa�ato� A
TnCK�~TnCK0
TnPF Inte��upt
TnOC
010
110
TCKn
Co�pa�ato� P Match
8-�it Co�pa�ato� P
000
Co�pa�ato� A Match
Output
Cont�ol
Pola�ity
Cont�ol
Pin
Cont�ol
TnM1� TnM0
TnIO1� TnIO0
TnPOL
TnCP
TPn
TnAF Inte��upt
TnIO1� TnIO0
Edge
Detecto�
CCRA
Standard Type TM Block Diagram – n = 0 for HT66F0185 only
Standard TM Operation
The size of Standard TM is 16-bit wide and its core is a 16-bit count-up counter which is driven by
a user selectable internal or external 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 comparator is 8-bit wide whose value is compared the
with highest eight bits in the counter while the CCRA is the sixteen bits and therefore compares all
counter bits.
The only way of changing the value of the 16-bit counter using the application program, is to
clear the counter by changing the TnON 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 including an input pin and can also control an output pin. All operating setup conditions are
selected using relevant internal registers.
Rev. 1.10
87
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Standard Type TM Register Description
Overall operation of the Standard TM is controlled using a series of registers. A read only register
pair exists to store the internal counter 16-bit value, while a read/write register pair exists to store
the internal 16-bit CCRA value. The TMnRP register is used to store the 8-bit CCRP value. The
remaining two registers are control registers which setup the different operating and control modes.
Bit
Register
Name
7
6
5
4
3
2
1
0
TMnC0
TnPAU
TnCK2
TnCK1
TnCK0
TnON
—
—
—
TMnC1
TnM1
TnM0
TnIO1
TnIO0
TnOC
TnPOL
TnDPX
TnCCLR
TMnDL
D7
D6
D5
D4
D3
D2
D1
D0
TMnDH
D15
D14
D13
D12
D11
D10
D9
D8
TMnAL
D7
D6
D5
D4
D3
D2
D1
D0
TMnAH
D15
D14
D13
D12
D11
D10
D9
D8
TMnRP
TnRP7
TnRP6
TnRP5
TnRP4
TnRP3
TnRP2
TnRP1
TnRP0
16-bit Standard TM Registers List – n = 0 for HT66F0185 only
TMnDL 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
TMn Counter Low Byte Register bit 7 ~ bit 0
TMn 16-bit Counter bit 7 ~ bit 0
TMnDH Register
Bit
7
6
5
4
3
2
1
0
Name
D15
D14
D13
D12
D11
D10
D9
D8
R/W
R
R
R
R
R
R
R
R
POR
0
0
0
0
0
0
0
0
Bit 7~0
TMn Counter High Byte Register bit 7 ~ bit 0
TMn 16-bit Counter bit 15 ~ bit 8
TMnAL 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 7~0
TMn CCRA Low Byte Register bit 7 ~ bit 0
TMn 16-bit CCRA bit 7 ~ bit 0
TMnAH Register
Bit
7
6
5
4
3
2
1
0
Name
D15
D14
D13
D12
D11
D10
D9
D8
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
Rev. 1.10
TMn CCRA High Byte Register bit 7 ~ bit 0
TMn 16-bit CCRA bit 15 ~ bit 8
88
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
TMnC0 Register
Bit
7
6
5
4
3
2
1
0
Name
TnPAU
TnCK2
TnCK1
TnCK0
TnON
—
—
—
R/W
R/W
R/W
R/W
R/W
R/W
—
—
—
POR
0
0
0
0
0
—
—
—
Bit 7TnPAU: TMn 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 TMn 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 6~4TnCK2~TnCK0: Select TMn Counter clock
000: fSYS/4
001: fSYS
010: fH/16
011: fH/64
100: fTBC
101: fH/8
110: TCKn rising edge clock
111: TCKn falling edge clock
These three bits are used to select the clock source for the TMn. 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 3TnON: TMn Counter On/Off control
0: Off
1: On
This bit controls the overall on/off function of the TMn. Setting the bit high enables
the counter to run while clearing the bit disables the TMn. Clearing this bit to zero
will stop the counter from counting and turn off the TMn 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 TMn is in
the Compare Match Output Mode then the TMn output pin will be reset to its initial
condition, as specified by the TnOC bit, when the TnON bit changes from low to high.
Bit 2~0
Rev. 1.10
Unimplemented, read as “0”
89
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
TMnC1 Register
Bit
7
6
5
4
3
2
1
0
Name
TnM1
TnM0
TnIO1
TnIO0
TnOC
TnPOL
TnDPX
TnCCLR
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 7~6TnM1~TnM0: Select TMn Operating 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 TMn. To ensure reliable operation
the TMn should be switched off before any changes are made to the TnM1 and TnM0
bits. In the Timer/Counter Mode, the TMn output pin control will be disabled.
Bit 5~4TnIO1~TnIO0: Select TPn pin output 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 TPn
01: Input capture at falling edge of TPn
10: Input capture at rising/falling edge of TPn
11: Input capture disabled
Timer/Counter Mode
Unused
These two bits are used to determine how the TMn output pin changes state when a
certain condition is reached. The function that these bits select depends upon in which
mode the TMn is running.
In the Compare Match Output Mode, the TnIO1 and TnIO0 bits determine how the
TMn 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 bits are both
zero, then no change will take place on the output. The initial value of the TMn output
pin should be setup using the TnOC bit in the TMnC1 register. Note that the output
level requested by the TnIO1 and TnIO0 bits must be different from the initial value
setup using the TnOC bit otherwise no change will occur on the TMn output pin when
a compare match occurs. After the TMn output pin changes state, it can be reset to its
initial level by changing the level of the TnON bit from low to high.
In the PWM Mode, the TnIO1 and TnIO0 bits determine how the TMn 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 only change the
values of the TnIO1 and TnIO0 bits only after the TMn has been switched off.
Unpredictable PWM outputs will occur if the TnIO1 and TnIO0 bits are changed when
the TMn is running.
Rev. 1.10
90
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Bit 3TnOC: TMn TPn Output control
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 TMn output pin. Its operation depends upon
whether TMn is being used in the Compare Match Output Mode or in the PWM Mode/
Single Pulse Output Mode. It has no effect if the TMn is in the Timer/Counter Mode.
In the Compare Match Output Mode it determines the logic level of the TMn output
pin before a compare match occurs. In the PWM Mode/Single Pulse Output Mode it
determines if the PWM signal is active high or active low.
Bit 2TnPOL: TMn TPn Output polarity control
0: Non-inverted
1: Inverted
This bit controls the polarity of the TPn output pin. When the bit is set high the TMn
output pin will be inverted and not inverted when the bit is zero. It has no effect if the
TMn is in the Timer/Counter Mode.
Bit 1TnDPX: TMn PWM duty/period 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 0TnCCLR: TMn Counter Clear condition selection
0: Comparator P match
1: Comparator A match
This bit is used to select the method which clears the counter. Remember that the
Standard TM contains two comparators, Comparator A and Comparator P, either of
which can be selected to clear the internal counter. With the TnCCLR 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 TnCCLR bit is not
used in the PWM Output, Single Pulse Output or Capture Input Mode.
Rev. 1.10
91
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
TMnRP Register
Bit
7
6
5
4
3
2
1
0
Name
TnRP7
TnRP6
TnRP5
TnRP4
TnRP3
TnRP2
TnRP1
TnRP0
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 7~0TnRP7~TnRP0: TMn CCRP 8-bit register, compared with the TMn counter bit 15~bit 8
Comparator P match period:
0: 65536 TMn clocks
1~255: (1~255) × 256 TMn clocks
These eight bits are used to setup the value on the internal CCRP 8-bit register, which
are then compared with the internal counter’s highest eight bits. The result of this
comparison can be selected to clear the internal counter if the TnCCLR bit is set to
zero. Setting the TnCCLR 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 eight counter bits, the compare values exist in 256 clock cycle multiples.
Clearing all eight bits to zero is in effect allowing the counter to overflow at its
maximum value.
Standard Type TM Operation 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 TnM1 and TnM0 bits in the TMnC1 register.
Compare Match Output Mode
To select this mode, bits TnM1 and TnM0 in the TMnC1 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 TnCCLR 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 TnAF and TnPF interrupt request flags for Comparator A and
Comparator P respectively, will both be generated.
If the TnCCLR bit in the TMnC1 register is high then the counter will be cleared when a compare
match occurs from Comparator A. However, here only the TnAF interrupt request flag will be
generated even if the value of the CCRP bits is less than that of the CCRA registers. Therefore when
TnCCLR is high no TnPF interrupt request flag will be generated. In the Compare Match Output
Mode, the CCRA can not be set to “0”.
As the name of the mode suggests, after a comparison is made, the TMn output pin, will change
state. The TMn output pin condition however only changes state when a TnAF interrupt request
flag is generated after a compare match occurs from Comparator A. The TnPF interrupt request flag,
generated from a compare match occurs from Comparator P, will have no effect on the TMn output
pin. The way in which the TMn output pin changes state are determined by the condition of the
TnIO1 and TnIO0 bits in the TMnC1 register. The TMn output pin can be selected using the TnIO1
and TnIO0 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 TMn output pin, which is setup after the
TnON bit changes from low to high, is setup using the TnOC bit. Note that if the TnIO1 and TnIO0
bits are zero then no pin change will take place.
Rev. 1.10
92
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Counter Value
Counter overflow
CCRP=0
0xFFFF
TnCCLR = 0; TnM [1:0] = 00
CCRP > 0
Counter cleared by CCRP value
CCRP > 0
Counter
Restart
Resume
CCRP
Pause
CCRA
Stop
Time
TnON
TnPAU
TnPOL
CCRP Int.
flag TnPF
CCRA Int.
flag TnAF
TMn O/P Pin
Output pin set to
initial Level Low
if TnOC=0
Output not affected by TnAF
flag. Remains High until reset by
TnON bit
Output Toggle with
TnAF flag
Here TnIO [1:0] = 11
Toggle Output select
Note TnIO [1:0] = 10
Active High Output select
Output Inverts
when TnPOL is high
Output Pin
Reset to Initial value
Output controlled by
other pin-shared function
Compare Match Output Mode – TnCCLR = 0
Note: 1. With TnCCLR=0 a Comparator P match will clear the counter
2. The TMn output pin is controlled only by the TnAF flag
3. The output pin is reset to itsinitial state by a TnON bit rising edge
4. n = 0 for HT66F0185 only
Rev. 1.10
93
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Counter Value
TnCCLR = 1; TnM [1:0] = 00
CCRA = 0
Counter overflow
CCRA > 0 Counter cleared by CCRA value
0xFFFF
CCRA=0
Resume
CCRA
Pause
Stop
Counter Restart
CCRP
Time
TnON
TnPAU
TnPOL
No TnAF flag
generated on
CCRA overflow
CCRA Int.
flag TnAF
CCRP Int.
flag TnPF
TMn O/P Pin
TnPF not
generated
Output pin set to
initial Level Low
if TnOC=0
Output does
not change
Output Toggle with
TnAF flag
Here TnIO [1:0] = 11
Toggle Output select
Output not affected by TnAF
flag. Remains High until
reset by TnON bit
Note TnIO [1:0] = 10
Active High Output select
Output Inverts
when TnPOL is high
Output Pin
Reset to Initial value
Output controlled by
other pin-shared function
Compare Match Output Mode – TnCCLR = 1
Note: 1. With TnCCLR=1 a Comparator A match will clear the counter
2. The TMn output pin is controlled only by the TnAF flag
3. The output pin is reset to its initial state by a TnON bit rising edge
4. A TnPF flag is not generated when TnCCLR=1
5. n = 0 for HT66F0185 only
Rev. 1.10
94
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Timer/Counter Mode
To select this mode, bits TnM1 and TnM0 in the TMnC1 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 TMn 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 TMn 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 TnM1 and TnM0 in the TMnC1 register should be set to 10 respectively
and also the TnIO1 and TnIO0 bits should be set to 10 respectively. The PWM function within
the TMn 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
TMn 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 TnCCLR 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 TnDPX bit in the TMnC1 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 TnOC bit in the TMnC1 register is used to
select the required polarity of the PWM waveform while the two TnIO1 and TnIO0 bits are used to
enable the PWM output or to force the TMn output pin to a fixed high or low level. The TnPOL bit
is used to reverse the polarity of the PWM output waveform.
• 16-bit STM, PWM Mode, Edge-aligned Mode, TnDPX=0
CCRP
1~255
0
Period
CCRP×256
65536
Duty
CCRA
If fSYS = 16MHz, TMn clock source is fSYS/4, CCRP = 2 and CCRA = 128,
The TMn PWM output frequency = (fSYS/4) / (2×256) = fSYS/2048 = 7.8125 kHz, duty = 128/(2×256)=
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%.
• 16-bit STM, PWM Mode, Edge-aligned Mode, TnDPX=1
CCRP
1~255
Period
0
CCRA
Duty
CCRP×256
65536
The PWM output period is determined by the CCRA register value together with the TM clock while
the PWM duty cycle is defined by the (CCRP×256) value except when the CCRP value is equal to 0.
Rev. 1.10
95
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Counter Value
TnDPX = 0; TnM [1:0] = 10
Counter cleared
by CCRP
Counter Reset when
TnON returns high
CCRP
Pause Resume
CCRA
Counter Stop if
TnON bit low
Time
TnON
TnPAU
TnPOL
CCRA Int.
flag TnAF
CCRP Int.
flag TnPF
TMn O/P Pin
(TnOC=1)
TMn O/P Pin
(TnOC=0)
PWM Duty Cycle
set by CCRA
PWM resumes
operation
PWM Period
set by CCRP
Output controlled by
other pin-shared function
Output Inverts
when TnPOL = 1
PWM Output Mode – TnDPX = 0
Note: 1. Here TnDPX=0 – Counter cleared by CCRP
2. A counter clear sets the PWM Period
3. The internal PWM function continues running even when TnIO [1:0] = 00 or 01
4. The TnCCLR bit has no influence on PWM operation
5. n = 0 for HT66F0185 only
Rev. 1.10
96
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Counter Value
TnDPX = 1; TnM [1:0] = 10
Counter cleared
by CCRA
Counter Reset when
TnON returns high
CCRA
Pause Resume
CCRP
Counter Stop if
TnON bit low
Time
TnON
TnPAU
TnPOL
CCRP Int.
flag TnPF
CCRA Int.
flag TnAF
TMn O/P Pin
(TnOC=1)
TMn O/P Pin
(TnOC=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 TnPOL = 1
PWM Output Mode – TnDPX = 1
Note: 1. Here TnDPX=1 – Counter cleared by CCRA
2. A counter clear sets the PWM Period
3. The internal PWM function continues even when TnIO [1:0] = 00 or 01
4. The TnCCLR bit has no influence on PWM operation
5. n = 0 for HT66F0185 only
Rev. 1.10
97
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Single Pulse Output Mode
To select this mode, bits TnM1 and TnM0 in the TMnC1 register should be set to 10 respectively
and also the TnIO1 and TnIO0 bits should be set to 11 respectively. The Single Pulse Output Mode,
as the name suggests, will generate a single shot pulse on the TMn output pin.
The trigger for the pulse output leading edge is a low to high transition of the TnON bit, which can
be implemented using the application program. However in the Single Pulse Mode, the TnON bit
can also be made to automatically change from low to high using the external TCKn pin, which will
in turn initiate the Single Pulse output. When the TnON bit transitions to a high level, the counter
will start running and the pulse leading edge will be generated. The TnON bit should remain high
when the pulse is in its active state. The generated pulse trailing edge will be generated when the
TnON 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 TnON 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 TMn interrupt. The counter
can only be reset back to zero when the TnON bit changes from low to high when the counter
restarts. In the Single Pulse Mode CCRP is not used. The TnCCLR and TnDPX bits are not used in
this Mode.
S/W Command
SET“TnON”
or
TCKn Pin
Transition
CCRA
Leading Edge
CCRA
Trailing Edge
TnON bit
0à1
TnON bit
1à0
S/W Command
CLR“TnON”
or
CCRA Compare
Match
TPn Output Pin
Pulse Width = CCRA Value
Single Pulse Generation
Rev. 1.10
98
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Counter Value
TnM [1:0] = 10 ; TnIO [1:0] = 11
Counter stopped
by CCRA
Counter Reset when
TnON returns high
CCRA
Pause
Counter Stops
by software
Resume
CCRP
Time
TnON
Software
Trigger
Auto. set by
TCKn pin
Cleared by
CCRA match
TCKn pin
Software
Trigger
Software
Trigger
Software
Clear
Software
Trigger
TCKn pin
Trigger
TnPAU
TnPOL
No CCRP Interrupts
generated
CCRP Int. Flag
TnPF
CCRA Int. Flag
TnAF
TMn O/P Pin
(TnOC=1)
TMn O/P Pin
(TnOC=0)
Output Inverts
when TnPOL = 1
Pulse Width
set by CCRA
Single Pulse Mode
Note: 1. Counter stopped by CCRA
2. CCRP is not used
3. The pulse triggered by the TCKn pin or by setting the TnON bit high
4. A TCKn pin active edge will automatically set the TnON bit high.
5. In the Single Pulse Mode, TnIO [1:0] must be set to “11” and can not be changed.
6. n = 0 for HT66F0185 only
Rev. 1.10
99
November 21, 2014
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A/D 8-Bit Flash MCU with EEPROM
Capture Input Mode
To select this mode bits TnM1 and TnM0 in the TMnC1 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 TPn pin, whose active edge can be a rising edge, a falling edge or both rising
and falling edges; the active edge transition type is selected using the TnIO1 and TnIO0 bits in
the TMnC1 register. The counter is started when the TnON bit changes from low to high which is
initiated using the application program.
When the required edge transition appears on the TPn pin the present value in the counter will be
latched into the CCRA registers and a TMn interrupt generated. Irrespective of what events occur on
the TPn pin the counter will continue to free run until the TnON 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 TMn 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 TnIO1 and
TnIO0 bits can select the active trigger edge on the TPn pin to be a rising edge, falling edge or both
edge types. If the TnIO1 and TnIO0 bits are both set high, then no capture operation will take place
irrespective of what happens on the TPn pin, however it must be noted that the counter will continue
to run. The TnCCLR and TnDPX bits are not used in this Mode.
Rev. 1.10
100
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Counter Value
TnM [1:0] = 01
Counter cleared
by CCRP
Counter Counter
Stop
Reset
CCRP
YY
Pause
Resume
XX
Time
TnON
TnPAU
Active
edge
Active
edge
Active edge
TMn capture pin
TPn
CCRA Int. Flag
TnAF
CCRP Int. Flag
TnPF
CCRA
Value
TnIO [1:0]
Value
XX
00 – Rising edge
YY
01 – Falling edge
XX
10 – Both edges
YY
11 – Disable Capture
Capture Input Mode
Note: 1. TnM [1:0] = 01 and active edge set by the TnIO [1:0] bits
2. A TMn Capture input pin active edge transfers the counter value to CCRA
3. TnCCLR bit not used
4. No output function -- TnOC and TnPOL bits are not used
5. CCRP determines the counter value and the counter has a maximum count value when CCRP is equal to
zero.
6. n = 0 for HT66F0185 only
Rev. 1.10
101
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A/D 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 one external input pin and can drive one external output pin.
Device
TM Core
TM No.
TM Input Pin
TM Output Pin
HT66F0175
10-bit PTM
TM0, TM1
TCK0, TCK1
TP0, TP1
HT66F0185
10-bit PTM
TM1
TCK1
TP1
CCRP
fSYS/�
fSYS
fH/16
fH/6�
fTBC
fH/8
001
�0~�9
011
10-�it Count-up Counte�
100
101
TnO�
TnPAU
111
TnCK�~TnCK0
Counte� Clea�
0
1
TnCCLR
�0~�9
10-�it Co�pa�ato� A
TnPF Inte��upt
TnOC
010
110
TCKn
Co�pa�ato� P Match
10-�it Co�pa�ato� P
000
Co�pa�ato� A Match
CCRA
Output
Cont�ol
Pola�ity
Cont�ol
Pin
Cont�ol
TnM1� TnM0
TnIO1� TnIO0
TnPOL
TnCP
TPn
TnAF Inte��upt
TnIO1� TnIO0
TnCAPTS
Edge
Detecto�
0
1
Periodic Type TM Block Diagram – n = 0 or 1
Periodic TM Operation
The size of Periodic TM is 10-bit wide and its core is a 10-bit count-up counter which is driven by
a user selectable internal or external 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 and CCRA comparators are 10-bit wide whose value is
respectively compared 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 TnON 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 pins. All operating setup conditions
are selected using relevant internal registers.
Rev. 1.10
102
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
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.
Register
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
TMnC0
TnPAU
TnCK2
TnCK1
TnCK0
TnON
—
—
—
TMnC1
TnM1
TnM0
TnIO1
TnIO0
TnOC
TnPOL
TnCAPTS
TnCCLR
TMnDL
D7
D6
D5
D4
D3
D2
D1
D0
TMnDH
—
—
—
—
—
—
D9
D8
TMnAL
D7
D6
D5
D4
D3
D2
D1
D0
TMnAH
—
—
—
—
—
—
D9
D8
TMnRPL
TnRP7
TnRP6
TnRP5
TnRP4
TnRP3
TnRP2
TnRP1
TnRP0
TMnRPH
—
—
—
—
—
—
TnRP9
TnRP8
Periodic TM Registers List – n = 0 or 1
TMnDL 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
TMn Counter Low Byte Register bit 7 ~ bit 0
TMn 10-bit Counter bit 7 ~ bit 0
TMnDH Register
Rev. 1.10
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 1~0
TMn Counter High Byte Register bit 1 ~ bit 0
TMn 10-bit Counter bit 9 ~ bit 8
103
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
TMnAL 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 7~0
TMn CCRA Low Byte Register bit 7 ~ bit 0
TMn 10-bit CCRA bit 7 ~ bit 0
TMnAH 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 1~0
TMn CCRA High Byte Register bit 1 ~ bit 0
TMn 10-bit CCRA bit 9 ~ bit 8
TMnRPL Register
Bit
7
6
5
4
3
2
1
0
Name
TnRP7
TnRP6
TnRP5
TnRP4
TnRP3
TnRP2
TnRP1
TnRP0
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 7~0TnRP7~TnRP0: TMn CCRP Low Byte Register bit 7 ~ bit 0
TMn 10-bit CCRP bit 7 ~ bit 0
TMnRPH Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
—
—
TnRP9
TnRP8
R/W
—
—
—
—
—
—
R/W
R/W
POR
—
—
—
—
—
—
0
0
Bit 7~2
Unimplemented, read as “0”
Bit 1~0TnRP9~TnRP8: TMn CCRP High Byte Register bit 1 ~ bit 0
TMn 10-bit CCRP bit 9 ~ bit 8
Rev. 1.10
104
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
TMnC0 Register
Bit
7
6
5
4
3
2
1
0
Name
TnPAU
TnCK2
TnCK1
TnCK0
TnON
—
—
—
R/W
R/W
R/W
R/W
R/W
R/W
—
—
—
POR
0
0
0
0
0
—
—
—
Bit 7TnPAU: TMn 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 TMn 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 6~4TnCK2~TnCK0: Select TMn Counter clock
000: fSYS/4
001: fSYS
010: fH/16
011: fH/64
100: fTBC
101: fH/8
110: TCKn rising edge clock
111: TCKn falling edge clock
These three bits are used to select the clock source for the TMn. 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 3TnON: TMn Counter On/Off control
0: Off
1: On
This bit controls the overall on/off function of the TMn. Setting the bit high enables
the counter to run while clearing the bit disables the TMn. Clearing this bit to zero
will stop the counter from counting and turn off the TMn 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 TMn is in
the Compare Match Output Mode then the TMn output pin will be reset to its initial
condition, as specified by the TnOC bit, when the TnON bit changes from low to high.
Bit 2~0
Rev. 1.10
Unimplemented, read as “0”
105
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
TMnC1 Register
Bit
7
6
5
4
3
2
Name
TnM1
TnM0
TnIO1
TnIO0
TnOC
TnPOL
1
0
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
TnCAPTS TnCCLR
Bit 7~6TnM1~TnM0: Select TMn Operating 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 TMn. To ensure reliable operation
the TMn should be switched off before any changes are made to the TnM1 and TnM0
bits. In the Timer/Counter Mode, the TMn output pin control will be disabled.
Bit 5~4TnIO1~TnIO0: Select TPn output 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 TPn or TCKn
01: Input capture at falling edge of TPn or TCKn
10: Input capture at rising/falling edge of TPn or TCKn
11: Input capture disabled
Timer/Counter Mode
Unused
These two bits are used to determine how the TMn output pin changes state when a
certain condition is reached. The function that these bits select depends upon in which
mode the TMn is running.
In the Compare Match Output Mode, the TnIO1 and TnIO0 bits determine how the
TMn output pin changes state when a compare match occurs from the Comparator A.
The TMn 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 bits are both
zero, then no change will take place on the output. The initial value of the TMn output
pin should be setup using the TnOC bit in the TMnC1 register. Note that the output
level requested by the TnIO1 and TnIO0 bits must be different from the initial value
setup using the TnOC bit otherwise no change will occur on the TMn output pin when
a compare match occurs. After the TMn output pin changes state, it can be reset to its
initial level by changing the level of the TnON bit from low to high.
In the PWM Mode, the TnIO1 and TnIO0 bits determine how the TMn output pin
changes state when a certain compare match condition occurs. The TMn output
function is modified by changing these two bits. It is necessary to only change the
values of the TnIO1 and TnIO0 bits only after the TMn has been switched off.
Unpredictable PWM outputs will occur if the TnIO1 and TnIO0 bits are changed when
the TMn is running.
Rev. 1.10
106
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Bit 3TnOC: TMn TPn Output control
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 TMn output pin. Its operation depends upon
whether TMn is being used in the Compare Match Output Mode or in the PWM Mode/
Single Pulse Output Mode. It has no effect if the TMn is in the Timer/Counter Mode.
In the Compare Match Output Mode it determines the logic level of the TMn output
pin before a compare match occurs. In the PWM Mode/Single Pulse Output Mode it
determines if the PWM signal is active high or active low.
Bit 2TnPOL: TMn TPn Output polarity control
0: Non-inverted
1: Inverted
This bit controls the polarity of the TPn output pin. When the bit is set high the TMn
output pin will be inverted and not inverted when the bit is zero. It has no effect if the
TMn is in the Timer/Counter Mode.
Bit 1TnCAPTS: TMn Capture Trigger Source selection
0: From TPn pin
1: From TCKn pin
Bit 0TnCCLR: TMn Counter Clear condition selection
0: Comparator P match
1: Comparator 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 TnCCLR 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 TnCCLR bit is not
used in the PWM Output, Single Pulse Output or Capture Input Mode.
Rev. 1.10
107
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Periodic Type TM Operation 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 TnM1 and TnM0 bits in the TMnC1 register.
Compare Match Output Mode
To select this mode, bits TnM1 and TnM0 in the TMnC1 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 TnCCLR 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 TnAF and TnPF interrupt request flags for Comparator A and
Comparator P respectively, will both be generated.
If the TnCCLR bit in the TMnC1 register is high then the counter will be cleared when a compare
match occurs from Comparator A. However, here only the TnAF interrupt request flag will be
generated even if the value of the CCRP bits is less than that of the CCRA registers. Therefore when
TnCCLR is high no TnPF interrupt request flag will be generated. In the Compare Match Output
Mode, the CCRA can not be set to “0”.
As the name of the mode suggests, after a comparison is made, the TMn output pin will change
state. The TMn output pin condition however only changes state when a TnAF interrupt request
flag is generated after a compare match occurs from Comparator A. The TnPF interrupt request flag,
generated from a compare match occurs from Comparator P, will have no effect on the TMn output
pin. The way in which the TMn output pin changes state are determined by the condition of the
TnIO1 and TnIO0 bits in the TMnC1 register. The TMn output pin can be selected using the TnIO1
and TnIO0 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 TMn output pin, which is setup after the
TnON bit changes from low to high, is setup using the TnOC bit. Note that if the TnIO1 and TnIO0
bits are zero then no pin change will take place.
Rev. 1.10
108
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Counter Value
Counter overflow
CCRP=0
0x3FF
TnCCLR = 0; TnM [1:0] = 00
CCRP > 0
Counter cleared by CCRP value
CCRP > 0
Counter
Restart
Resume
CCRP
Pause
CCRA
Stop
Time
TnON
TnPAU
TnPOL
CCRP Int. Flag
TnPF
CCRA Int. Flag
TnAF
TMn O/P
Pin
Output pin set to
initial Level Low
if TnOC=0
Output not affected by TnAF
flag. Remains High until reset
by TnON bit
Output Toggle with
TnAF flag
Here TnIO [1:0] = 11
Toggle Output select
Note TnIO [1:0] = 10
Active High Output select
Output Inverts
when TnPOL is high
Output Pin
Reset to Initial value
Output controlled by
other pin-shared function
Compare Match Output Mode – TnCCLR = 0
Note: 1. With TnCCLR=0, a Comparator P match will clear the counter
2. The TMn output pin is controlled only by the TnAF flag
3. The output pin is reset to its initial state by a TnON bit rising edge
4. n = 0 or 1 for HT66F0175 while n = 1 for HT66F0185
Rev. 1.10
109
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Counter Value
TnCCLR = 1; TnM [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
TnON
TnPAU
TnPOL
No TnAF flag
generated on
CCRA overflow
CCRA Int. Flag
TnAF
CCRP Int. Flag
TnPF
TMn O/P
Pin
TnPF not
generated
Output pin set to
initial Level Low
if TnOC=0
Output does
not change
Output Toggle with
TnAF flag
Here TnIO [1:0] = 11
Toggle Output select
Output not affected by TnAF
flag. Remains High until reset
by TnON bit
Note TnIO [1:0] = 10
Active High Output select
Output Inverts
when TnPOL is high
Output Pin
Reset to Initial value
Output controlled by
other pin-shared function
Compare Match Output Mode - TnCCLR = 1
Note: 1. With TnCCLR=1, a Comparator A match will clear the counter
2. The TMn output pin is controlled only by the TnAF flag
3. The output pin is reset to its initial state by a TnON bit rising edge
4. A TnPF flag is not generated when TnCCLR =1
5. n = 0 or 1 for HT66F0175 while n = 1 for HT66F0185
Rev. 1.10
110
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A/D 8-Bit Flash MCU with EEPROM
Timer/Counter Mode
To select this mode, bits TnM1 and TnM0 in the TMnC1 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 TMn 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 TMn 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 TnM1 and TnM0 in the TMnC1 register should be set to 10 respectively
and also the TnIO1 and TnIO0 bits should be set to 10 respectively. The PWM function within
the TMn 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
TMn 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 TnCCLR 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 TnOC bit in the TMnC1 register is used to
select the required polarity of the PWM waveform while the two TnIO1 and TnIO0 bits are used to
enable the PWM output or to force the TMn output pin to a fixed high or low level. The TnPOL bit
is used to reverse the polarity of the PWM output waveform.
• 10-bit PTM, PWM Mode
CCRP
1~1023
0
Period
1~1023
1024
Duty
CCRA
If fSYS=16MHz, TM clock source select fSYS/4, CCRP=512 and CCRA=128,
The TMn PWM output frequency = (fSYS/4)/512 = fSYS/2048 = 7.8125kHz, 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%.
Rev. 1.10
111
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Counter Value
TnM [1:0] = 10
Counter cleared
by CCRP
Counter Reset when
TnON returns high
CCRP
Pause Resume
CCRA
Counter Stop if
TnON bit low
Time
TnON
TnPAU
TnPOL
CCRA Int. Flag
TnAF
CCRP Int. Flag
TnPF
TMn O/P Pin
(TnOC=1)
TMn O/P Pin
(TnOC=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 TnPOL = 1
PWM Mode
Note: 1. The counter is cleared by CCRP.
2. A counter clear sets the PWM Period
3. The internal PWM function continues running even when TnIO [1:0] = 00 or 01
4. The TnCCLR bit has no influence on PWM operation
5. n = 0 or 1 for HT66F0175 while n = 1 for HT66F0185
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Single Pulse Output Mode
To select this mode, bits TnM1 and TnM0 in the TMnC1 register should be set to 10 respectively
and also the TnIO1 and TnIO0 bits should be set to 11 respectively. The Single Pulse Output Mode,
as the name suggests, will generate a single shot pulse on the TMn output pin.
The trigger for the pulse output leading edge is a low to high transition of the TnON bit, which can
be implemented using the application program. However in the Single Pulse Mode, the TnON bit
can also be made to automatically change from low to high using the external TCKn pin, which will
in turn initiate the Single Pulse output. When the TnON bit transitions to a high level, the counter
will start running and the pulse leading edge will be generated. The TnON bit should remain high
when the pulse is in its active state. The generated pulse trailing edge will be generated when the
TnON 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 TnON 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 TMn interrupt. The counter
can only be reset back to zero when the TnON bit changes from low to high when the counter
restarts. In the Single Pulse Mode CCRP is not used. The TnCCLR is not used in this Mode.
S/W Command
SET“TnON”
or
TCKn Pin
Transition
CCRA
Leading Edge
CCRA
Trailing Edge
TnON bit
0à1
TnON bit
1à0
S/W Command
CLR“TnON”
or
CCRA Compare
Match
TPn Output Pin
Pulse Width = CCRA Value
Single Pulse Generation
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A/D 8-Bit Flash MCU with EEPROM
Counter Value
TnM [1:0] = 10 ; TnIO [1:0] = 11
Counter stopped
by CCRA
Counter Reset when
TnON returns high
CCRA
Pause
Counter Stops
by software
Resume
CCRP
Time
TnON
Software
Trigger
Auto. set by
TCKn pin
Cleared by
CCRA match
TCKn pin
Software
Trigger
Software
Trigger
Software
Clear
Software
Trigger
TCKn pin
Trigger
TnPAU
TnPOL
No CCRP Interrupts
generated
CCRP Int. Flag
TnPF
CCRA Int. Flag
TnAF
TMn O/P Pin
(TnOC=1)
TMn O/P Pin
(TnOC=0)
Pulse Width
set by CCRA
Output Inverts
when TnPOL = 1
Single Pulse Mode
Note: 1. Counter stopped by CCRA
2. CCRP is not used
3. The pulse triggered by the TCKn pin or by setting the TnON bit high
4. A TCKn pin active edge will automatically set the TnON bit high.
5. In the Single Pulse Mode, TnIO [1:0] must be set to “11” and can not be changed.
6. n = 0 or 1 for HT66F0175 while n = 1 for HT66F0185
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A/D 8-Bit Flash MCU with EEPROM
Capture Input Mode
To select this mode bits TnM1 and TnM0 in the TMnC1 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 TPn or TCKn pin, selected by the TnCAPTS bit in the TMnC1 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 TnIO1 and TnIO0 bits in the TMnC1 register. The counter
is started when the TnON bit changes from low to high which is initiated using the application
program.
When the required edge transition appears on the TPn or TCKn pin the present value in the counter
will be latched into the CCRA registers and a TMn interrupt generated. Irrespective of what events
occur on the TPn or TCKn pin the counter will continue to free run until the TnON 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 TMn 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 TnIO1
and TnIO0 bits can select the active trigger edge on the TPn or TCKn pin to be a rising edge, falling
edge or both edge types. If the TnIO1 and TnIO0 bits are both set high, then no capture operation
will take place irrespective of what happens on the TPn or TCKn pin, however it must be noted that
the counter will continue to run.
As the TPn or TCKn pin is pin shared with other functions, care must be taken if the TMn is in the
Input Capture 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 TnCCLR, TnOC and TnPOL bits are not
used in this Mode.
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A/D 8-Bit Flash MCU with EEPROM
Counter Value
TnM [1:0] = 01
Counter cleared
by CCRP
Counter Counter
Stop
Reset
CCRP
YY
Pause
Resume
XX
Time
TnON
TnPAU
Active
edge
Active
edge
Active edge
TMn capture pin
TPn or TCKn
CCRA Int. Flag
TnAF
CCRP Int. Flag
TnPF
CCRA
Value
TnIO [1:0]
Value
XX
00 – Rising edge
YY
01 – Falling edge
XX
10 – Both edges
YY
11 – Disable Capture
Capture Input Mode
Note: 1. TnM [1:0] = 01 and active edge set by the TnIO [1:0] bits
2. A TMn Capture input pin active edge transfers the counter value to CCRA
3. TnCCLR bit not used
4. No output function – TnOC and TnPOL bits are not used
5. CCRP determines the counter value and the counter has a maximum count value when CCRP is equal to
zero.
6. n = 0 or 1 for HT66F0175 while n = 1 for HT66F0185
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A/D 8-Bit Flash MCU with EEPROM
Analog to Digital Converter
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
These 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. It also can convert the internal signals, such as the Bandgap
reference voltage, into a 12-bit digital value. The external or internal analog signal to be converted is
determined by the SAINS2~SAINS0 bits together with the SACS2~SACS0 bits. Note that when the
external and internal analog signals are simultaneously selected to be converted, the internal analog
signal will have the priority. In the meantime the external analog signal will temporarily be switched
off until the internal analog signal is deselected. 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.
The accompanying block diagram shows the internal structure of the A/D converter together with its
associated registers.
Device
External Input Channel
Internal Analog Signals
A/D Signal Select Bits
HT66F0175
AN0~AN7
VDD, VDD/2, VDD/4, VR, VR/2, VR/4
SAINS2~SAINS0;
SACS2~SACS0
HT66F0185
AN0~AN7
VDD, VDD/2, VDD/4, VR, VR/2, VR/4
SAINS2~SAINS0;
SACS2~SACS0
VDD
fSYS
ACE7~ACE0
SACS�~SACS0
A�0
A�1
SACKS�~
SACKS0
÷ ��
ADCE�
(�=0~7)
VSS
A/D Clock
SADOL
A/D Conve�te�
A�7
ADRFS
SADOH
A/D Data
Registe�s
A/D Refe�ence Voltage
START
ADBZ
ADCE�
VREF
SAI�S�~SAI�S0
VDD
VDD/�
VDD/�
VR
VR/�
VR/�
SAVRS3~SAVRS0
VBG
VRI
PGA
VREFI
(Gain=1~�)
VREFIPS
ADPGAE�
VREFPS
VDD
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 A/D Converter data 12-bit value. One register, ACERL, is used to configure the
external analog input pin function. The remaining three registers are control registers which setup
the operating and control function of the A/D converter.
Bit
Register
Name
7
6
5
4
3
2
1
0
SADOL
(ADRFS=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
SACS2
SACS1
SACS0
SADC0
START
ADBZ
ADCEN
ADRFS
—
SADC1
SAINS2
SAINS10
SAINS0
—
—
SADC2
ADPGAEN
VBGEN
ACERL
ACE7
ACE6
SACKS2 SACKS1 SACKS0
VREFIPS VREFPS SAVRS3 SAVRS2 SAVRS1 SAVRS0
ACE5
ACE4
ACE3
ACE2
ACE1
ACE0
A/D Converter Registers List
A/D Converter Data Registers – SADOL, SADOH
As these 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. The A/D data registers contents will keep unchanged if the A/D
converter is disabled.
ADRFS
0
1
SADOH
7
6
D11 D10
0
0
5
4
D9
D8
0
0
SADOL
3
2
1
0
7
D7
D6
D5
D4
D3
D11 D10
D9
D8
D7
6
5
4
3
2
1
0
D2
D1
D0
0
0
0
0
D6
D5
D4
D3
D2
D1
D0
A/D Converter Data Registers
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A/D 8-Bit Flash MCU with EEPROM
A/D Converter Control Registers – SADC0, SADC1, SADC2, ACERL
To control the function and operation of the A/D converter, three 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 these 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 SACS2~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 will be selected
to be converted and the SACS2~SACS0 bits can deternine 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 can be selected to be converted. The internal analog signals can be
derived from the A/D converter supply power, VDD, or internal reference voltage, VR, 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.
SAINS [2:0]
SACS [2:0]
Input Signals
Description
000, 100
000~111
AN0~AN7
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
101
xxx
VR
110
xxx
VR/2
Internal reference voltage/2
111
xxx
VR/4
Internal reference voltage/4
External channel analog input
A/D converter power supply voltage
Internal reference voltage
A/D Converter Input Signal Selection
The analog input pin function selection bits in the ACERL register determine which pins on I/O
Ports are used as external analog channels 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 functions will be removed. In addition, any internal pullhigh resistor connected to the pin will be automatically removed if the pin is selected to be an A/D
converter input.
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• SADC0 Register
Bit
7
6
5
4
3
2
1
0
Name
START
ADBZ
ADCEN
ADRFS
—
SACS2
SACS1
SACS0
R/W
R/W
R
R/W
R/W
—
R/W
R/W
R/W
POR
0
0
0
0
—
0
0
0
Bit 7START: Start the A/D Conversion
0→1→0: Start
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 to 1 to indicate that the A/D conversion is initiated. The ADBZ flag will be
cleared to 0 after the A/D conversion is complete.
Bit 5ADCEN: A/D Converter function enable control
0: Disable
1: Enable
This bit controls the A/D internal function. This bit should be set to one 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/SADOL, will keep unchanged.
Bit 4ADRFS: A/D conversion data format select
0: A/D converter data format → SADOH = D [11:4]; SADOL = D [3:0]
1: A/D converter 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
Unimplemented, read as “0”
Bit 2~0SACS2~SACS0: A/D converter external analog input channel select
000: AN0
001: AN1
010: AN2
011: AN3
100: AN4
101: AN5
110: AN6
111: AN7
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• SADC1 Register
Bit
7
6
5
4
3
2
1
0
Name
SAINS2
SAINS10
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 select
000, 100: External signal – External analog channel input
001: Internal signal – Internal A/D converter power supply voltage VDD
010: Internal signal – Internal A/D converter power supply voltage VDD/2
011: Internal signal – Internal A/D converter power supply voltage VDD/4
101: Internal signal – Internal reference voltage VR
110: Internal signal – Internal reference voltage VR/2
111: Internal signal – Internal reference voltage VR/4
When the internal analog signal is selected to be converted, the external channel input
signal will automatically be switched off regardless of the SACS2~SACS0 bit field
value. The internal reference voltage can be derived from various sources selected
using the SAVRS3~SAVRS0 bits in the SADC2 register.
Bit 4~3
Unimplemented, read as “0”
Bit 2~0SACKS2~SACKS0: A/D conversion clock source select
000: fSYS
001: fSYS/2
010: fSYS/4
011: fSYS/8
100: fSYS/16
101: fSYS/32
110: fSYS/64
111: fSYS/128
These bits are used to select the clock source for the A/D converter.
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• SADC2 Register
Bit
Name
7
6
5
4
ADPGAEN VBGEN VREFIPS VREFPS
3
2
1
0
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 7ADPGAEN: A/D converter PGA function enable control
0: Disable
1: Enable
This bit controls the internal PGA 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 converted signal or reference voltage by the A/D converter. If the
internal reference voltage is not used by the A/D converter, then the PGA function
should be properly configured to conserve power.
Bit 6VBGEN: Internal Bandgap reference voltage enable control
0: Disable
1: Enable
This bit 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 LVD or 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.
Bit 5VREFIPS: VREFI pin selection bit
0: Disable – VREFI pin is not selected
1: Enable – VREFI pin is selected
Bit 4VREFPS: VREF pin selection bit
0: Disable – VREF pin is not selected
1: Enable – VREF pin is selected
Bit 3~0SAVRS3~SAVRS0: A/D Converter reference voltage select
0000: VDD
0001: VREFI
0010: VREFI × 2
0011: VREFI × 3
0100: VREFI × 4
1001: Reserved, can not be used.
1010: VBG × 2
1011: VBG × 3
1100: VBG × 4
Others: VDD
When the A/D converter reference voltage source is selected to derive from the
internal VBG voltage, the reference voltage which comes from the external VDD or
VREFI pin will be automatically switched off.
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A/D 8-Bit Flash MCU with EEPROM
• ACERL Register
Bit
7
6
5
4
3
2
1
0
Name
ACE7
ACE6
ACE5
ACE4
ACE3
ACE2
ACE1
ACE0
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 7ACE7: Define PB3 is A/D input or not
0: Not A/D input
1: A/D input, AN7
Bit 6ACE6: Define PA7 is A/D input or not
0: Not A/D input
1: A/D input, AN6
Bit 5ACE5: Define PA6 is A/D input or not
0: Not A/D input
1: A/D input, AN5
Bit 4ACE4: Define PA5 is A/D input or not
0: Not A/D input
1: A/D input, AN4
Bit 3ACE3: Define PA4 is A/D input or not
0: Not A/D input
1: A/D input, AN3
Bit 2ACE2: Define PB2 is A/D input or not
0: Not A/D input
1: A/D input, AN2
Bit 1ACE1: Define PB1 is A/D input or not
0: Not A/D input
1: A/D input, AN1
Bit 0ACE0: Define PB0 is A/D input or not
0: Not A/D input
1: A/D input, AN0
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A/D Input Pins
All of the A/D analog input pins are pin-shared with the I/O pins as well as other functions. The
corresponding pin-shared function selection bits in the ACERL register determine which external
input pins are selected as A/D converter analog channel inputs or other functional pins. If the
corresponding pin is setup to be an A/D converter analog channel input, the original pin functions
will be 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 port control register to enable the A/D
input as when the relevant A/D input function selection 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 input 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 VREF pin. The analog input values must not be allowed to exceed the
value of VREF. Note that the VREFI or VREF pin function selection bit in the SADC2 register must
be properly configured before the reference voltage pin function is used.
A/D Reference Voltage
The reference voltage supply to the A/D Converter can be supplied from the positive power supply
pin, VDD, 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 a
programmable gain amplifier except the voltage sourced from VDD. The PGA 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-shared function selection bits. Note that the desired selected reference voltage will
be output on the VREF pin which is pin-shared with other functions. As the VREFI and VREF pins
both are pin-shared with other functions, when the VREFI or VREF pin is selected as the reference
voltage supply pin, the VREFI or VREF pin-shared function selection bit should be properly
configured to disable other pin-shared functions.
A/D Operation
The START bit in the SADC0 register is used to start the AD conversion. When the microcontroller
sets this bit from low to high and then low again, an analog to digital conversion cycle will be
initiated.
The ADBZ bit in the SADC0 register is used to indicate whether the analog to digital conversion
process is in progress or not. 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 corresponding interrupt control bits are enabled, an 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 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.
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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 range of permissible A/D clock period,
tADCK, is from 0.5μs to 10μs, care must be taken for system clock frequencies. For example, as the
system clock operates at a frequency of 8MHz, the SACKS2~SACKS0 bits should not be set to 000,
001 or 111. Doing so will give A/D clock periods that are less than the minimum 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 devices, special care must
be taken, as the values may be less than the specified minimum A/D Clock Period.
A/D Clock Period (tADCK)
fSYS
SACKS[2:0]
= 000
(fSYS)
SACKS[2:0]
= 001
(fSYS/2)
SACKS[2:0]
= 010
(fSYS/4)
SACKS[2:0]
= 011
(fSYS/8)
SACKS[2:0]
= 100
(fSYS/16)
SACKS[2:0]
= 101
(fSYS/32)
SACKS[2:0]
= 110
(fSYS/64)
SACKS[2:0]
= 111
(fSYS/128)
128μs *
1 MHz
1μs
2μs
4μs
8μs
16μs *
32μs *
64μs *
2 MHz
500ns
1μs
2μs
4μs
8μs
16μs *
32μs *
64μs *
4 MHz
250ns *
500ns
1μs
2μs
4μs
8μs
16μs *
32μs *
8 MHz
125ns *
250ns *
500ns
1μs
2μs
4μs
8μs
16μs *
12 MHz
83ns *
167ns *
333ns *
667ns
1.33μs
2.67μs
5.33μs
10.67μs *
16 MHz
62.5ns *
125ns *
250ns *
500ns
1μs
2μs
4μs
8μs
20 MHz
50ns *
100ns *
200ns *
400ns *
800ns
1.6μs
3.2μs
6.4μs
A/D Clock Period Examples
Controlling the power on/off function of the A/D converter circuitry is implemented using the
ADCEN bit in the SADC0 register. This bit must be set high to power on the A/D converter. When
the ADCEN 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, if the ADCEN bit is high, then some power will still be
consumed. In power conscious applications it is therefore recommended that the ADCEN is set low
to reduce power consumption when the A/D converter function is not being used.
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 (1)
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 16 tADCK clock cycles where tADCK is equal to the A/D clock period.
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tO��ST
ADCE�
off
on
off
A/D sa�pling ti�e
tADS
A/D sa�pling ti�e
tADS
Sta�t of A/D conve�sion
Sta�t of A/D conve�sion
on
START
ADBZ
SACS[�:0]
(SAI�S =000B)
End of A/D
conve�sion
011B
A/D channel
switch
Sta�t of A/D conve�sion
End of A/D
conve�sion
010B
000B
tADC
A/D conve�sion ti�e
tADC
A/D conve�sion ti�e
001B
tADC
A/D conve�sion ti�e
A/D Conversion Timing
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 ADCEN 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 pins should first be configured as A/D input function by configuring the
relevant pin-shared function control bits. The desired analog channel then should be selected by
configuring the SACS bit field. After this step, go to Step 6.
Step 5
If the A/D input signal is selected to come from the internal analog signal, the SAINS bit field
should be properly configured and then the external channel input will automatically be disconnected
regardless of the SACS bit field value. After this step, go to Step 6.
Step 6
Select the reference voltgage source by configuring the SAVRS3~SAVRS0 bits.
Step 7
Select the A/D converter output data format by configuring the ADRFS bit.
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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 bontrol bit, EMI, and the A/D
conversion interrupt control bit, ADE, must both be set high in advance.
Step 9
The A/D conversion procedure can now be initialized 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 complete, the ADBZ flag will go low and then the output data can be read from SADOH and
SADOL registers.
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.
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 setting bit ADCEN low 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 VREF voltage, this gives a single bit
analog input value of VREF divided by 4096.
1 LSB = VREF ÷ 4096
The A/D Converter input voltage value can be calculated using the following equation:
A/D input voltage = A/D output digital value × VREF ÷ 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 VREF level.
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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;
mov a,03H
mov SADC1,a ;
set ADCEN
mov a,03H ;
mov ACERL,a
mov a,00H
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. 1.10
disable ADC interrupt
select fSYS/8 as A/D clock and switch off VBG voltage
setup ACERL 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
save
read
save
low byte conversion result value
result to user defined register
high byte conversion result value
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;
mov a,03H
mov SADC1,a ;
set ADCEN
mov a,03h ;
mov ACERL,a
mov a,00h
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. 1.10
disable ADC interrupt
select fSYS/8 as A/D clock and switch off VBG voltage
setup ACERL 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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Serial Interface Module – SIM
These devices contain a Serial Interface Module, which includes both the four-line SPI interface or
two-line I2C interface types, to allow an easy method of communication with external peripheral
hardware. Having relatively simple communication protocols, these serial interface types allow
the microcontroller to interface to external SPI or I2C based hardware such as sensors, Flash or
EEPROM memory, etc. The SIM interface pins are pin-shared with other I/O pins and therefore the
SIM interface functional pins must first be selected using the corresponding pin-shared function
selection bits. As both interface types share the same pins and registers, the choice of whether the
SPI or I2C type is used is made using the SIM operating mode control bits, named SIM2~SIM0, in
the SIMC0 register. These pull-high resistors of the SIM pin-shared I/O pins are selected using pullhigh control registers when the SIM function is enabled and the corresponding pins are used as SIM
input pins.
SPI Interface
The SPI interface is often used to communicate with external peripheral devices such as sensors,
Flash or EEPROM memory devices, etc. Originally developed by Motorola, the four line SPI
interface is a synchronous serial data interface that has a relatively simple communication protocol
simplifying the programming requirements when communicating with external hardware devices.
The communication is full duplex and operates as a slave/master type, where the devices can be
either master or slave. Although the SPI interface specification can control multiple slave devices
from a single master, these devices provided only one SCS pin. If the master needs to control
multiple slave devices from a single master, the master can use I/O pin to select the slave devices.
SPI Interface Operation
The SPI interface is a full duplex synchronous serial data link. It is a four line interface with pin
names SDI, SDO, SCK and SCS. Pins SDI and SDO are the Serial Data Input and Serial Data
Output lines, SCK is the Serial Clock line and SCS is the Slave Select line. As the SPI interface pins
are pin-shared with normal I/O pins and with the I2C function pins, the SPI interface pins must first
be selected by configuring the pin-shared function selection bits and setting the correct bits in the
SIMC0 and SIMC2 registers. After the desired SPI configuration has been set it can be disabled or
enabled using the SIMEN bit in the SIMC0 register. Communication between devices connected
to the SPI interface is carried out in a slave/master mode with all data transfer initiations being
implemented by the master. The Master also controls the clock signal. As the devices only contain
a single SCS pin only one slave device can be utilized. The SCS pin is controlled by software, set
CSEN bit to 1 to enable SCS pin function, set CSEN bit to 0 the SCS pin will be floating state.
The SPI function in these devices offer the following features:
• Full duplex synchronous data transfer
• Both Master and Slave modes
• LSB first or MSB first data transmission modes
• Transmission complete flag
• Rising or falling active clock edge
The status of the SPI interface pins is determined by a number of factors such as whether the devices
are in the master or slave mode and upon the condition of certain control bits such as CSEN and
SIMEN.
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SPI Master/Slave Connection

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SPI Registers
There are three internal registers which control the overall operation of the SPI interface. These are
the SIMD data register and two registers SIMC0 and SIMC2. Note that the SIMC1 register is only
used by the I2C interface.
Bit
Register
Name
7
6
SIMC0
SIM2
SIM1
SIM0
—
SIMC2
D7
D6
CKPOLB
CKEG
MLS
CSEN
SIMD
D7
D6
D5
D4
D3
D2
5
4
3
2
SIMDEB1 SIMDEB0
1
0
SIMEN
SIMICF
WCOL
TRF
D1
D0
SPI Registers List
SIMD Register
The SIMD register is used to store the data being transmitted and received. The same register is used
by both the SPI and I2C functions. Before the devices write data to the SPI bus, the actual data to
be transmitted must be placed in the SIMD register. After the data is received from the SPI bus, the
device can read it from the SIMD register. Any transmission or reception of data from the SPI bus
must be made via the SIMD 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
x
x
x
x
x
x
x
x
“x”: unknown
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There are also two control registers for the SPI interface, SIMC0 and SIMC2. Note that the SIMC2
register also has the name SIMA which is used by the I2C function. The SIMC1 register is not used
by the SPI function, only by the I2C function. Register SIMC0 is used to control the enable/disable
function and to set the data transmission clock frequency. Register SIMC2 is used for other control
functions such as LSB/MSB selection, write collision flag, etc.
SIMC0 Register
Bit
7
6
5
4
Name
SIM2
SIM1
SIM0
—
3
R/W
R/W
R/W
R/W
—
R/W
POR
1
1
1
—
0
2
1
0
SIMEN
SIMICF
R/W
R/W
R/W
0
0
0
SIMDEB1 SIMDEB0
Bit 7~5SIM2~SIM0: SIM Operating Mode Control
000: SPI master mode; SPI clock is fSYS /4
001: SPI master mode; SPI clock is fSYS /16
010: SPI master mode; SPI clock is fSYS /64
011: SPI master mode; SPI clock is fTBC
100: SPI master mode; SPI clock is TM1 CCRP match frequency/2
101: SPI slave mode
110: I2C slave mode
111: Non SIM function
These bits setup the overall operating mode of the SIM function. As well as selecting
if the I2C or SPI function, they are used to control the SPI Master/Slave selection and
the SPI Master clock frequency. The SPI clock is a function of the system clock but
can also be chosen to be sourced from TM1. If the SPI Slave Mode is selected then the
clock will be supplied by an external Master device.
Bit 4
Unimplemented, read as “0”
Bit 3~2SIMDEB1~SIMDEB0: I2C Debounce Time Selection
00: No debounce
01: 2 system clock debounce
1x: 4 system clock debounce
Bit 1SIMEN: SIM Enable Control
0: Disable
1: Enable
The bit is the overall on/off control for the SIM interface. When the SIMEN bit is
cleared to zero to disable the SIM interface, the SDI, SDO, SCK and SCS, or SDA and
SCL lines will lose their SPI or I2C function and the SIM operating current will be
reduced to a minimum value. When the bit is high the SIM interface is enabled. If the
SIM is configured to operate as an SPI interface via the SIM2~SIM0 bits, the contents
of the SPI control registers will remain at the previous settings when the SIMEN bit
changes from low to high and should therefore be first initialised by the application
program. If the SIM is configured to operate as an I2C interface via the SIM2~SIM0
bits and the SIMEN bit changes from low to high, the contents of the I2C control bits
such as HTX and TXAK will remain at the previous settings and should therefore be
first initialised by the application program while the relevant I2C flags such as HCF,
HAAS, HBB, SRW and RXAK will be set to their default states.
Bit 0SIMICF: SIM Incomplete Flag
0: SIM incomplete condition not occurred
1: SIM incomplete condition occured
This bit is only available when the SIM is configured to operate in an SPI slave mode.
If the SPI operates in the slave mode with the SIMEN and CSEN bits both being set
to 1 but the SCS line is pulled high by the external master device before the SPI data
transfer is completely finished, the SIMICF bit will be set to 1 together with the TRF
bit. When this condition occurs, the corresponding interrupt will occur if the interrupt
function is enabled. However, the TRF bit will not be set to 1 if the SIMICF bit is set
to 1 by software application program.
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SIMC2 Register
Bit
7
6
5
4
3
2
1
0
Name
D7
D6
CKPOLB
CKEG
MLS
CSEN
WCOL
TRF
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 7~6
Undefined bits
These bits can be read or written by the application program.
Bit 5CKPOLB: SPI clock line base condition selection
0: The SCK line will be high when the clock is inactive.
1: The SCK line will be low when the clock is inactive.
The CKPOLB bit determines the base condition of the clock line, if the bit is high,
then the SCK line will be low when the clock is inactive. When the CKPOLB bit is
low, then the SCK line will be high when the clock is inactive.
Bit 4CKEG: SPI SCK clock active edge type selection
CKPOLB=0
0: SCK is high base level and data capture at SCK rising edge
1: SCK is high base level and data capture at SCK falling edge
CKPOLB=1
0: SCK is low base level and data capture at SCK falling edge
1: SCK is low base level and data capture at SCK rising edge
The CKEG and CKPOLB bits are used to setup the way that the clock signal outputs
and inputs data on the SPI bus. These two bits must be configured before data transfer
is executed otherwise an erroneous clock edge may be generated. The CKPOLB bit
determines the base condition of the clock line, if the bit is high, then the SCK line
will be low when the clock is inactive. When the CKPOLB bit is low, then the SCK
line will be high when the clock is inactive. The CKEG bit determines active clock
edge type which depends upon the condition of CKPOLB bit.
Bit 3MLS: SPI data shift order
0: LSB first
1: MSB first
This is the data shift select bit and is used to select how the data is transferred, either
MSB or LSB first. Setting the bit high will select MSB first and low for LSB first.
Bit 2CSEN: SPI SCS pin control
0: Disable
1: Enable
The CSEN bit is used as an enable/disable for the SCS pin. If this bit is low, then the
SCS pin will be disabled and placed into a floating condition. If the bit is high, the SCS
pin will be enabled and used as a select pin.
Bit 1WCOL: SPI write collision flag
0: No collision
1: Collision
The WCOL flag is used to detect whether a data collision has occurred or not. If this
bit is high, it means that data has been attempted to be written to the SIMD register
duting a data transfer operation. This writing operation will be ignored if data is being
transferred. This bit can be cleared by the application program.
Bit 0TRF: SPI Transmit/Receive complete flag
0: SPI data is being transferred
1: SPI data transfer is completed
The TRF bit is the Transmit/Receive Complete flag and is set to 1 automatically when
an SPI data transfer is completed, but must cleared to 0 by the application program. It
can be used to generate an interrupt.
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SPI Communication
After the SPI interface is enabled by setting the SIMEN bit high, then in the Master Mode, when
data is written to the SIMD register, transmission/reception will begin simultaneously. When the
data transfer is complete, the TRF flag will be set automatically, but must be cleared using the
application program. In the Slave Mode, when the clock signal from the master has been received,
any data in the SIMD register will be transmitted and any data on the SDI pin will be shifted into
the SIMD register. The master should output a SCS signal to enable the slave devices before a
clock signal is provided. The slave data to be transferred should be well prepared at the appropriate
moment relative to the SCS signal depending upon the configurations of the CKPOLB bit and CKEG
bit. The accompanying timing diagram shows the relationship between the slave data and SCS signal
for various configurations of the CKPOLB and CKEG bits.
The SPI master mode will continue to function even in the IDLE1 Mode if the selected SPI clock
source is running.
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SPI Master Mode Timing
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SPI Slave Mode Timing – CKEG = 1
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A/D 8-Bit Flash MCU with EEPROM
I2C Interface
The I 2C interface is used to communicate with external peripheral devices such as sensors,
EEPROM memory etc. Originally developed by Philips, it is a two line low speed serial interface
for synchronous serial data transfer. The advantage of only two lines for communication, relatively
simple communication protocol and the ability to accommodate multiple devices on the same bus
has made it an extremely popular interface type for many applications.
I2C Master Slave Bus Connection
I2C interface Operation
The I2C serial interface is a two line interface, a serial data line, SDA, and serial clock line, SCL. As
many devices may be connected together on the same bus, their outputs are both open drain types.
For this reason it is necessary that external pull-high resistors are connected to these outputs. Note
that no chip select line exists, as each device on the I2C bus is identified by a unique address which
will be transmitted and received on the I2C bus.
When two devices communicate with each other on the bidirectional I2C bus, one is known as the
master device and one as the slave device. Both master and slave can transmit and receive data,
however, it is the master device that has overall control of the bus. For these devices, which only
operate in slave mode, there are two methods of transferring data on the I2C bus, the slave transmit
mode and the slave receive mode.
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„ I2C Block Diagram
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S T A R T s ig n a l
fro m M a s te r
S e n d s la v e a d d r e s s
a n d R /W b it fr o m M a s te r
A c k n o w le d g e
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S e n d d a ta b y te
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A c k n o w le d g e
fr o m s la v e
S T O P s ig n a l
fro m M a s te r
The SIMDEB1 and SIMDEB0 bits determine the debounce time of the I2C interface. This uses
the system clock to in effect add a debounce time to the external clock to reduce the possibility
of glitches on the clock line causing erroneous operation. The debounce time, if selected, can be
chosen to be either 2 or 4 system clocks. To achieve the required I2C data transfer speed, there
exists a relationship between the system clock, fSYS, and the I2C debounce time. For either the I2C
Standard or Fast mode operation, users must take care of the selected system clock frequency and
the configured debounce time to match the criterion shown in the following table.
I2C Debounce Time Selection
I2C Standard Mode (100kHz)
I2C Fast Mode (400kHz)
No Devounce
fSYS > 2 MHz
fSYS > 5 MHz
2 system clock debounce
fSYS > 4 MHz
fSYS > 10 MHz
4 system clock debounce
fSYS > 8 MHz
fSYS > 20 MHz
I2C Minimum fSYS Frequency
I2C Registers
There are three control registers associated with the I2C bus, SIMC0, SIMC1 and SIMTOC, one
slave address register, SIMA, and one data register, SIMD. The SIMD register, which is shown in
the above SPI section, is used to store the data being transmitted and received on the I2C bus. Before
the microcontroller writes data to the I2C bus, the actual data to be transmitted must be placed in the
SIMD register. After the data is received from the I2C bus, the microcontroller can read it from the
SIMD register. Any transmission or reception of data from the I2C bus must be made via the SIMD
register.
Note that the SIMA register also has the name SIMC2 which is used by the SPI function. Bit SIMEN
and bits SIM2~SIM0 in register SIMC0 are used by the I2C interface.
Bit
Register
Name
7
6
5
4
SIMC0
SIM2
SIM1
SIM0
—
SIMC1
HCF
HAAS
HBB
HTX
TXAK
SIMA
IICA6
IICA5
IICA4
IICA3
IICA2
SIMD
D7
D6
D5
D4
D3
D2
3
2
1
0
SIMEN
SIMICF
SRW
IAMWU
RXAK
IICA1
IICA0
D0
D1
D0
SIMDEB1 SIMDEB0
SIMTOC SIMTOEN SIMTOF SIMTOS5 SIMTOS4 SIMTOS3 SIMTOS2 SIMTOS1 SIMTOS0
I2C Registers List
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
SIMD Register
The SIMD register is used to store the data being transmitted and received. The same register is used
by both the SPI and I2C functions. Before the device writes data to the I2C bus, the actual data to
be transmitted must be placed in the SIMD register. After the data is received from the I2C bus, the
device can read it from the SIMD register. Any transmission or reception of data from the I2C bus
must be made via the SIMD 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
x
x
x
x
x
x
x
x
“x”: unknown
SIMA Register
The SIMA register is also used by the SPI interface but has the name SIMC2. The SIMA register is
the location where the 7-bit slave address of the slave device is stored. Bits 7~1 of the SIMA register
define the device slave address. Bit 0 is not defined.
When a master device, which is connected to the I2C bus, sends out an address, which matches the
slave address in the SIMA register, the slave device will be selected. Note that the SIMA register is
the same register address as SIMC2 which is used by the SPI interface.
Bit
7
6
5
4
3
2
1
0
Name
IICA6
IICA5
IICA4
IICA3
IICA2
IICA1
IICA0
D0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
x
x
x
x
x
x
x
x
“x”: unknown
Bit 7~1IICA6~IICA0: I2C slave address
IICA6~IICA0 is the I2C slave address bit 6 ~ bit 0
Bit 0
Undefined bit
The bit can be read or written by the application program.
There are also three control registers for the I2C interface, SIMC0, SIMC1 and SIMTOC. The
register SIMC0 is used to control the enable/disable function and to set the data transmission
clock frequency.The SIMC1 register contains the relevant flags which are used to indicate the I2C
communication status. The SIMTOC register is used to control the I2C bus time-out function which
is described in the I2C Time-out Control section.
Rev. 1.10
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A/D 8-Bit Flash MCU with EEPROM
SIMC0 Register
Bit
7
6
5
4
Name
SIM2
SIM1
SIM0
—
3
R/W
R/W
R/W
R/W
—
R/W
POR
1
1
1
—
0
2
1
0
SIMEN
SIMICF
R/W
R/W
R/W
0
0
0
SIMDEB1 SIMDEB0
Bit 7~5SIM2~SIM0: SIM Operating Mode Control
000: SPI master mode; SPI clock is fSYS /4
001: SPI master mode; SPI clock is fSYS /16
010: SPI master mode; SPI clock is fSYS /64
011: SPI master mode; SPI clock is fTBC
100: SPI master mode; SPI clock is TM1 CCRP match frequency/2
101: SPI slave mode
110: I2C slave mode
111: Non SIM function
These bits setup the overall operating mode of the SIM function. As well as selecting
if the I2C or SPI function, they are used to control the SPI Master/Slave selection and
the SPI Master clock frequency. The SPI clock is a function of the system clock but
can also be chosen to be sourced from TM1. If the SPI Slave Mode is selected then the
clock will be supplied by an external Master device.
Bit 4
Unimplemented, read as “0”
Bit 3~2SIMDEB1~SIMDEB0: I2C Debounce Time Selection
00: No debounce
01: 2 system clock debounce
1x: 4 system clock debounce
Bit 1SIMEN: SIM Enable Control
0: Disable
1: Enable
The bit is the overall on/off control for the SIM interface. When the SIMEN bit is
cleared to zero to disable the SIM interface, the SDI, SDO, SCK and SCS, or SDA and
SCL lines will lose their SPI or I2C function and the SIM operating current will be
reduced to a minimum value. When the bit is high the SIM interface is enabled. If the
SIM is configured to operate as an SPI interface via the SIM2~SIM0 bits, the contents
of the SPI control registers will remain at the previous settings when the SIMEN bit
changes from low to high and should therefore be first initialised by the application
program. If the SIM is configured to operate as an I2C interface via the SIM2~SIM0
bits and the SIMEN bit changes from low to high, the contents of the I2C control bits
such as HTX and TXAK will remain at the previous settings and should therefore be
first initialised by the application program while the relevant I2C flags such as HCF,
HAAS, HBB, SRW and RXAK will be set to their default states.
Bit 0SIMICF: SIM Incomplete Flag
0: SIM incomplete condition not occurred
1: SIM incomplete condition occured
This bit is only available when the SIM is configured to operate in an SPI slave mode.
If the SPI operates in the slave mode with the SIMEN and CSEN bits both being set
to 1 but the SCS line is pulled high by the external master device before the SPI data
transfer is completely finished, the SIMICF bit will be set to 1 together with the TRF
bit. When this condition occurs, the corresponding interrupt will occur if the interrupt
function is enabled. However, the TRF bit will not be set to 1 if the SIMICF bit is set
to 1 by software application program.
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A/D 8-Bit Flash MCU with EEPROM
SIMC1 Register
Bit
7
6
5
4
3
2
1
0
Name
HCF
HAAS
HBB
HTX
TXAK
SRW
IAMWU
RXAK
R/W
R
R
R
R/W
R/W
R/W
R/W
R
POR
1
0
0
0
0
0
0
1
Bit 7HCF: I C Bus data transfer completion flag
0: Data is being transferred
1: Completion of an 8-bit data transfer
The HCF flag is the data transfer flag. This flag will be zero when data is being
transferred. Upon completion of an 8-bit data transfer the flag will go high and an
interrupt will be generated.
2
Bit 6HAAS: I2C Bus address match flag
0: Not address match
1: Address match
The HAAS flag is the address match flag. This flag is used to determine if the slave
device address is the same as the master transmit address. If the addresses match then
this bit will be high, if there is no match then the flag will be low.
Bit 5HBB: I2C Bus busy flag
0: I2C Bus is not busy
1: I2C Bus is busy
The HBB flag is the I2C busy flag. This flag will be “1” when the I2C bus is busy
which will occur when a START signal is detected. The flag will be set to “0” when
the bus is free which will occur when a STOP signal is detected.
Bit 4HTX: I2C slave device transmitter/receiver selection
0: Slave device is the receiver
1: Slave device is the transmitter
Bit 3TXAK: I2C bus transmit acknowledge flag
0: Slave send acknowledge flag
1: Slave does not send acknowledge flag
The TXAK bit is the transmit acknowledge flag. After the slave device receipt of 8-bits
of data, this bit will be transmitted to the bus on the 9th clock from the slave device.
The slave device must always set TXAK bit to “0” before further data is received.
Bit 2SRW: I2C slave read/write flag
0: Slave device should be in receive mode
1: Slave device should be in transmit mode
The SRW flag is the I 2C Slave Read/Write flag. This flag determines whether
the master device wishes to transmit or receive data from the I2C bus. When the
transmitted address and slave address is match, that is when the HAAS flag is set high,
the slave device will check the SRW flag to determine whether it should be in transmit
mode or receive mode. If the SRW flag is high, the master is requesting to read data
from the bus, so the slave device should be in transmit mode. When the SRW flag
is zero, the master will write data to the bus, therefore the slave device should be in
receive mode to read this data.
Bit 1IAMWU: I2C Address Match Wake-Up control
0: Disable
1: Enable – must be cleared by the application program after wake-up
This bit should be set to 1 to enable the I2C address match wake up from the SLEEP
or IDLE Mode. If the IAMWU bit has been set before entering either the SLEEP or
IDLE mode to enable the I2C address match wake up, then this bit must be cleared by
the application program after wake-up to ensure correction device operation.
Rev. 1.10
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A/D 8-Bit Flash MCU with EEPROM
Bit 0RXAK: I2C bus receive acknowledge flag
0: Slave receives acknowledge flag
1: Slave does not receive acknowledge flag
The RXAK flag is the receiver acknowledge flag. When the RXAK flag is “0”, it
means that a acknowledge signal has been received at the 9th clock, after 8 bits of data
have been transmitted. When the slave device in the transmit mode, the slave device
checks the RXAK flag to determine if the master receiver wishes to receive the next
byte. The slave transmitter will therefore continue sending out data until the RXAK
flag is “1”. When this occurs, the slave transmitter will release the SDA line to allow
the master to send a STOP signal to release the I2C Bus.
I2C Bus Communication
Communication on the I2C bus requires four separate steps, a START signal, a slave device address
transmission, a data transmission and finally a STOP signal. When a START signal is placed on
the I2C bus, all devices on the bus will receive this signal and be notified of the imminent arrival of
data on the bus. The first seven bits of the data will be the slave address with the first bit being the
MSB. If the address of the slave device matches that of the transmitted address, the HAAS bit in the
SIMC1 register will be set and an I2C interrupt will be generated. After entering the interrupt service
routine, the slave device must first check the condition of the HAAS and SIMTOF bits to determine
whether the interrupt source originates from an address match, 8-bit data transfer completion or
I2C bus time-out occurrence. During a data transfer, note that after the 7-bit slave address has been
transmitted, the following bit, which is the 8th bit, is the read/write bit whose value will be placed in
the SRW bit. This bit will be checked by the slave device to determine whether to go into transmit or
receive mode. Before any transfer of data to or from the I2C bus, the microcontroller must initialise
the bus, the following are steps to achieve this:
• Step 1
Set the SIM2~SIM0 bits to “110” and SIMEN bit to “1” in the SIMC0 register to enable the I2C
bus.
• Step 2
Write the slave address of the device to the I2C bus address register SIMA.
• Step 3
Set the SIME interrupt enable bit of the interrupt control register to enable the SIM interrupt.

  ­ € ‚ ƒ  „        I2C Bus Initialisation Flow Chart
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A/D 8-Bit Flash MCU with EEPROM
I2C Bus Start Signal
The START signal can only be generated by the master device connected to the I2C bus and not by
the slave device. This START signal will be detected by all devices connected to the I2C bus. When
detected, this indicates that the I2C bus is busy and therefore the HBB bit will be set. A START
condition occurs when a high to low transition on the SDA line takes place when the SCL line
remains high.
I2C Slave Address
The transmission of a START signal by the master will be detected by all devices on the I2C bus.
To determine which slave device the master wishes to communicate with, the address of the slave
device will be sent out immediately following the START signal. All slave devices, after receiving
this 7-bit address data, will compare it with their own 7-bit slave address. If the address sent out by
the master matches the internal address of the microcontroller slave device, then an internal I2C bus
interrupt signal will be generated. The next bit following the address, which is the 8th bit, defines
the read/write status and will be saved to the SRW bit of the SIMC1 register. The slave device will
then transmit an acknowledge bit, which is a low level, as the 9th bit. The slave device will also set
the status flag HAAS when the addresses match.
As an I2C bus interrupt can come from three sources, when the program enters the interrupt
subroutine, the HAAS and SIMTOF bits should be examined to see whether the interrupt source has
come from a matching slave address, the completion of a data byte transfer or the I2C bus time-out
occurrence. When a slave address is matched, the devices must be placed in either the transmit mode
and then write data to the SIMD register, or in the receive mode where it must implement a dummy
read from the SIMD register to release the SCL line.
I2C Bus Read/Write Signal
The SRW bit in the SIMC1 register defines whether the master device wishes to read data from the
I2C bus or write data to the I2C bus. The slave device should examine this bit to determine if it is to
be a transmitter or a receiver. If the SRW flag is “1” then this indicates that the master device wishes
to read data from the I2C bus, therefore the slave device must be setup to send data to the I2C bus as
a transmitter. If the SRW flag is “0” then this indicates that the master wishes to send data to the I2C
bus, therefore the slave device must be setup to read data from the I2C bus as a receiver.
I2C Bus Slave Address Acknowledge Signal
After the master has transmitted a calling address, any slave device on the I 2C bus, whose
own internal address matches the calling address, must generate an acknowledge signal. The
acknowledge signal will inform the master that a slave device has accepted its calling address. If no
acknowledge signal is received by the master then a STOP signal must be transmitted by the master
to end the communication. When the HAAS flag is high, the addresses have matched and the slave
device must check the SRW flag to determine if it is to be a transmitter or a receiver. If the SRW flag
is high, the slave device should be setup to be a transmitter so the HTX bit in the SIMC1 register
should be set to “1”. If the SRW flag is low, then the microcontroller slave device should be setup as
a receiver and the HTX bit in the SIMC1 register should be set to “0”.
Rev. 1.10
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A/D 8-Bit Flash MCU with EEPROM
I2C Bus Data and Acknowledge Signal
The transmitted data is 8-bits wide and is transmitted after the slave device has acknowledged
receipt of its slave address. The order of serial bit transmission is the MSB first and the LSB last.
After receipt of 8-bits of data, the receiver must transmit an acknowledge signal, level “0”, before
it can receive the next data byte. If the slave transmitter does not receive an acknowledge bit signal
from the master receiver, then the slave transmitter will release the SDA line to allow the master
to send a STOP signal to release the I2C Bus. The corresponding data will be stored in the SIMD
register. If setup as a transmitter, the slave device must first write the data to be transmitted into the
SIMD register. If setup as a receiver, the slave device must read the transmitted data from the SIMD
register.
When the slave receiver receives the data byte, it must generate an acknowledge bit, known as
TXAK, on the 9th clock. The slave device, which is setup as a transmitter will check the RXAK bit
in the SIMC1 register to determine if it is to send another data byte, if not then it will release the
SDA line and await the receipt of a STOP signal from the master.
€

€

­
         ­ Note: * When a slave address is matched, the devices must be placed in either the transmit mode
and then write data to the SIMD register, or in the receive mode where it must implement a
dummy read from the SIMD register to release the SCL line.
I2C Communication Timing Diagram
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A/D 8-Bit Flash MCU with EEPROM
     
            I2C Bus ISR Flow Chart
I2C Time-out Control
In order to reduce the I2C lockup problem due to reception of erroneous clock sources, a time-out
function is provided. If the clock source connected to the I2C bus is not received for a while, then the
I2C circuitry and registers will be reset after a certain time-out period. The time-out counter starts to
count on an I2C bus “START” & “address match”condition, and is cleared by an SCL falling edge.
Before the next SCL falling edge arrives, if the time elapsed is greater than the time-out period
specified by the SIMTOC register, then a time-out condition will occur. The time-out function will
stop when an I2C “STOP” condition occurs.
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A/D 8-Bit Flash MCU with EEPROM
S ta rt
S C L
S R W
S la v e A d d r e s s
0
1
S D A
1
1
0
1
0
A C K
1
0
I2 C t i m e - o u t
c o u n te r s ta rt
S to p
S C L
1
0
0
1
0
1
0
0
S D A
I2 C t im e - o u t c o u n t e r r e s e t
o n S C L n e g a tiv e tr a n s itio n
I2C Time-out
When an I2C time-out counter overflow occurs, the counter will stop and the SIMTOEN bit will
be cleared to zero and the SIMTOF bit will be set high to indicate that a time-out condition has
occurred. The time-out condition will also generate an interrupt which uses the I2C interrrupt vector.
When an I2C time-out occurs, the I2C internal circuitry will be reset and the registers will be reset
into the following condition:
Register
After I2C Time-out
SIMD, SIMA, SIMC0
No change
SIMC1
Reset to POR condition
I C Register after Time-out
2
The SIMTOF flag can be cleared by the application program. There are 64 time-out period selections
which can be selected using the SIMTOS bits in the SIMTOC register. The time-out duration is
calculated by the formula: ((1~64) × (32/fSUB)). This gives a time-out period which ranges from
about 1ms to 64ms.
SIMTOC Register
Bit
7
Name
SIMTOEN
6
5
4
3
2
1
0
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
SIMTOF SIMTOS5 SIMTOS4 SIMTOS3 SIMTOS2 SIMTOS1 SIMTOS0
Bit 7SIMTOEN: SIM I C Time-out function control
0: Disable
1: Enable
2
Bit 6SIMTOF: SIM I2C Time-out flag
0: No time-out occurred
1: Time-out occurred
Bit 5~0SIMTOS5~SIMTOS0: SIM I2C Time-out period selection
I2C Time-out clock source is fSUB/32
32
I2C Time-out period is equal to (SIMTOS[5:0] + 1) ×
fSUB
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Comparators
An analog comparator is contained only within the HT66F0185 device. The comparator function
offers flexibility via their register controlled features such as power-down, polarity select, hysteresis
etc. In sharing their pins with normal I/O pins the comparators do not waste precious I/O pins if
there functions are otherwise unused.
Comparator
Comparator Operation
The HT66F0185 device contains a comparator function which is used to compare two analog
voltages and provide an output based on their difference. Full control over the internal comparator is
provided via the control register CPC assigned to the comparator. The comparator output is recorded
via a bit in the control register, but can also be transferred out onto a shared I/O pin. Additional
comparator functions include output polarity, hysteresis functions and power down control.
Any pull-high resistors connected to the shared comparator input pins will be automatically
disconnected when the comparator is enabled. As the comparator inputs approach their switching
level, some spurious output signals may be generated on the comparator output due to the slow
rising or falling nature of the input signals. This can be minimised by selecting the hysteresis
function which applies a small amount of positive feedback to the comparator. Ideally the
comparator should switch at the point where the positive and negative inputs signals are at the same
voltage level. However, unavoidable input offsets introduce some uncertainties here. The hysteresis
function, if enabled, also increases the switching offset value.
Comparator Interrupt
The comparator possesses its own interrupt function. When the comparator output changes state,
its relevant interrupt flag will be set, and if the corresponding interrupt enable bit is set, then a jump
to its relevant interrupt vector will be executed. Note that it is the changing state of the COUT bit
and not the output pin which generates an interrupt. If the microcontroller is in the SLEEP or IDLE
Mode and the Comparator is enabled, then if the external input lines cause the Comparator output to
change state, the resulting generated interrupt flag will also generate a wake-up. If it is required to
disable a wake-up from occurring, then the interrupt flag should be first set high before entering the
SLEEP or IDLE Mode.
Programming Considerations
If the comparator is enabled, it will remain active when the microcontroller enters the SLEEP or
IDLE Mode, however as it will consume a certain amount of power, the user may wish to consider
disabling it before the SLEEP or IDLE Mode is entered. As comparator pins are shared with normal
I/O pins, the I/O registers for these pins will be read as zero (port control register is “1”) or read as
port data register value (port control register is “0”) if the comparator function is enabled.
Rev. 1.10
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A/D 8-Bit Flash MCU with EEPROM
CPC Register
Bit
7
6
5
4
3
Name
CSEL
CEN
CPOL
COUT
COS
2
1
R/W
R/W
R/W
R/W
R
R/W
R/W
R/W
R/W
POR
1
0
0
0
0
0
0
1
CMPEG1 CMPEG0
0
CHYEN
Bit 7CSEL: Select Comparator pins or I/O pins
0: I/O pin selected
1: Comparator input pins C+ and C- selected
This is the Comparator input pin or I/O pin select bit. If the bit is high, the comparator
input pins will be enabled. As a result, these two pins will lose their I/O pin functions.
Any pull-high configuration options associated with the comparator shared pins will
also be automatically disconnected.
Bit 6CEN: Comparator ON/Off control
0: Off
1: On
This is the Comparator on/off control bit. If the bit is zero the comparator will be
switched off and no power consumed even if analog voltages are applied to its inputs.
For power sensitive applications this bit should be cleared to zero if the comparator is
not used or before the device enters the SLEEP or IDLE mode.
Bit 5CPOL: Comparator Output polarity
0: Output not inverted
1: Output inverted
This is the comparator polarity bit. If the bit is zero then the COUT bit will reflect
the non-inverted output condition of the comparator. If the bit is high the comparator
COUT bit will be inverted.
Bit 4COUT: Comparator Output bit
CPOL = 0
0: C+ < C1: C+ > CCPOL = 1
0: C+ > C1: C+ < CThis bit stores the comparator output bit. The polarity of the bit is determined by the
voltages on the comparator inputs and by the condition of the CPOL bit.
Bit 3COS: Comparator Output path select
0: CX pin selected (compare output can output to CX pin)
1: I/O pin selected (compare output only internal use)
Bit 2~1CMPEG1~CMPEG0: Comparator output interrupt trigger edge select
00: rising edge → comparator interrupt trigger signal generated if COUT changed
state from 0 to 1
01: falling edge → comparator interrupt trigger signal generated if COUT changed
state from 1 to 0
1x: both edge → comparator interrupt trigger signal generated if COUT changed
state from 0 to 1 or 1 to 0
Bit 0CHYEN: Comparator Hysteresis function control
0: Off
1: On
This is the hysteresis control bit and if set high will apply a limited amount of
hysteresis to the comparator, as specified in the Comparator Electrical Characteristics
table. The positive feedback induced by hysteresis reduces the effect of spurious
switching near the comparator threshold.
Rev. 1.10
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A/D 8-Bit Flash MCU with EEPROM
SCOM/SSEG Function for LCD
The devices have the capability of driving external LCD panels. The common and segment pins
for LCD driving, SCOM0~SCOM5 and SSEG0~SSEG19 or SSEG0~SSEG23, are pin-shared with
certain pins on the I/O ports. The LCD signals, COM and SEG, are generated using the application
program.
LCD Operation
An external LCD panel can be driven using the devices by configuring the I/O pins as common pins
and segment pins. The LCD driver function is controlled using the LCD control registers which in
addition to controlling the overall on/off function also controls the R-type bias current on the SCOM
and SSEG pins. This enables the LCD COM and SEG driver to generate the necessary VSS, (1/3)
VDD, (2/3)VDD and VDD voltage levels for LCD 1/3 bias operation.
The LCDEN bit in the SLCDC0 register is the overall master control for the LCD driver. This bit is
used in conjunction with the COMnEN and SEGnEN bits to select which I/O pins are used for LCD
driving. Note that the corresponding Port Control register does not need to first setup the pins as
outputs to enable the LCD driver operation.
VDD
VDD
COMnE� COMSEGSn
6
6
SCOM0/SSEG0
(�/3) VDD
(1/3) VDD
LCD
COM/SEG
Analog Switch
LCD
Voltage
Select
Circuit
SCOM5/SSEG5
SSEG6
SSEG�
� = 19 fo� HT66F0175
� = �3 fo� HT66F0185
ISEL[1:0]
SEG�E�
LCDE�
FRAME
Software Controlled LCD Driver Structure
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A/D 8-Bit Flash MCU with EEPROM
LCD Frames
A cyclic LCD waveform includes two frames known as Frame 0 and Frame 1 for which the
following offers a functional explanation.
• Frame 0
To select Frame 0, clear the FRAME bit in the SLCDC 0 register to 0.
In frame 0, the COM signal output can have a value of VDD or a VBIAS value of (1/3)×VDD. The SEG
signal output can have a value of VSS or a VBIAS value of (2/3)×VDD.
• Frame 1
To select Frame 1, set the FRAME bit in the SLCDC0 register to 1.
In frame 1, the COM signal output can have a value of VSS or a VBIAS value of (2/3)×VDD. The SEG
signal output can have a value of VDD or a VBIAS value of (1/3)×VDD.
The COMn waveform is controlled by the application program using the FRAME bit in the
SLCDC0 register and the corresponding pin-shared I/O data bit for the respective COM pin to
determine whether the COMn output has a value of VDD, VSS or VBIAS. The SEGm waveform is
controlled in a similar way using the FRAME bit and the corresponding pin-shared I/O data bit for
the respective SEG pin to determine whether the SEGm output has a value of VDD, VSS or VBIAS.
The accompanying waveform diagram shows a typical 1/3 bias LCD waveform generated using the
application program together with the LCD voltage select circuit. Note that the depiction of a “1”
in the diagram illustrates an illuminated LCD pixel. The COM signal polarity generated on pins
SCOM0~SCOM5, whether “0” or “1”, are generated using the corresponding pin-shared I/O data
register bit.
Frame 0
Frame 1
1
COM0
0
0
0
0
Frame 0
0
Frame 1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
1
1
1
0
1
0
0
1
1
1
VDD
VSS
1
0
1
1
(2/3) VDD
(1/3) VDD
VDD
(2/3) VDD
0
1
VDD
(2/3) VDD
1
1
0
1
VSS
(1/3) VDD
0
1
1
0
1
0
(1/3) VDD
VSS
1
1
0
SEG1
0
1
0
0
1
0
0
1
0
1
1
0
1
0
1
0
1
0
1
0
VDD
(2/3) VDD
1
0
0
1
SEG0
0
(2/3) VDD
VSS
0
1
1
0
0
0
VDD
(1/3) VDD
1
1
0
0
1
0
(2/3) VDD
VSS
0
1
1
0
0
VDD
(1/3) VDD
0
0
1
COM3
0
1
0
0
1
0
0
0
0
0
0
1
0
1
0
0
0
1
COM2
1
1
0
Frame 0
1
1
0
0
0
1
COM1
0
Frame 0
(1/3) VDD
1
VSS
Note: The logical values shown in the above diagram are the corresponding pin-shared I/O data bit value.
1/3 Bias LCD Waveform – 4-COM & 2-SEG application
Rev. 1.10
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A/D 8-Bit Flash MCU with EEPROM
LCD Control Registers
The LCD COM and SEG driver enables a range of selections to be provided to suit the requirement
of the LCD panel which is being used. The bias resistor choice is implemented using the ISEL1
and ISEL0 bits in the SLCDC0 register. All COM and SEG pins are pin-shared with I/O pins and
selected as COM and SEG pins using the corresponding pin function selection bits in the SLCDCn
registers respectively.
Bit
Register
Name
7
6
5
4
3
2
1
0
SLCDC0
FRAME
ISEL1
ISEL0
LCDEN
COM3EN
COM2EN
COM1EN
COM0EN
SLCDC1
COM5EN
COM4EN
SLCDC2
SEG13EN
SEG12EN
COMSEGS5 COMSEGS4 COMSEGS3 COMSEGS2 COMSEGS1 COMSEGS0
SEG11EN
SEG10EN
SEG9EN
SEG8EN
SEG7EN
SEG6EN
SLCDC3
—
—
SEG19EN
SEG18EN
SEG17EN
SEG16EN
SEG15EN
SEG14EN
LCD Driver Control Registers List – HT66F0175
Bit
Register
Name
7
6
5
4
3
2
1
0
SLCDC0
FRAME
ISEL1
ISEL0
LCDEN
COM3EN
COM2EN
COM1EN
COM0EN
SLCDC1
COM5EN
COM4EN
SLCDC2
SEG13EN
SEG12EN
COMSEGS5 COMSEGS4 COMSEGS3 COMSEGS2 COMSEGS1 COMSEGS0
SEG11EN
SEG10EN
SEG9EN
SEG8EN
SEG7EN
SEG6EN
SLCDC3
SEG21EN
SEG20EN
SEG19EN
SEG18EN
SEG17EN
SEG16EN
SEG15EN
SEG14EN
SLCDC4
—
—
—
—
—
—
SEG23EN
SEG22EN
LCD Driver Control Registers List – HT66F0185
SLCDC0 Register
Bit
7
6
5
4
Name
FRAME
ISEL1
ISEL0
LCDEN
3
2
1
0
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
COM3EN COM2EN COM1EN COM0EN
Bit 7FRAME: SCOM/SSEG Output Frame selection
0: Frame 0
1: Frame 1
Bit 6~5ISEL1~ISEL0: Select SCOM/SSEG typical bias current (VDD=5V)
00: 8.3μA
01: 16.7μA
10: 50μA
11: 100μA
Bit 4LCDEN: SCOM/SSEG Module enable control
0: Disable
1: Enable
The SCOMn and SSEGm lines can be enabled using COMnEN and SEGmEN if the
LCDEN bit is set to 1. When the LCD bit is cleared to 0, then the SCOMn and SSEGm
outputs will be fixed at a VSS level.
Bit 3COM3EN: SCOM3/SSEG3 or other pin function select
0: Other pin-shared functions
1: SCOM3/SSEG3 function
Bit 2COM2EN: SCOM2/SSEG2 or other pin function select
0: Other pin-shared functions
1: SCOM2/SSEG2 function
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Bit 1COM1EN: SCOM1/SSEG1 or other pin function select
0: Other pin-shared functions
1: SCOM1/SSEG1 function
Bit 0COM0EN: SCOM0/SSEG0 or other pin function select
0: Other pin-shared functions
1: SCOM0/SSEG0 function
SLCDC1 Register
Bit
Name
7
6
5
4
3
2
1
0
COM5EN COM4EN COMSEGS5 COMSEGS4 COMSEGS3 COMSEGS2 COMSEGS1 COMSEGS0
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 7COM5EN: SCOM5/SSEG5 or other pin function select
0: Other pin-shared functions
1: SCOM5/SSEG5 function
Bit 6COM4EN: SCOM4/SSEG4 or other pin function select
0: Other pin-shared functions
1: SCOM4/SSEG4 function
Bit 5COMSEGS5: SCOM5 or SSEG5 pin function select
0: SCOM5
1: SSEG5
Bit 4COMSEGS4: SCOM4 or SSEG4 pin function select
0: SCOM4
1: SSEG4
Bit 3COMSEGS3: SCOM3 or SSEG3 pin function select
0: SCOM3
1: SSEG3
Bit 2COMSEGS2: SCOM2 or SSEG2 pin function select
0: SCOM2
1: SSEG2
Bit 1COMSEGS1: SCOM1 or SSEG1 pin function select
0: SCOM1
1: SSEG1
Bit 0COMSEGS0: SCOM0 or SSEG0 pin function select
0: SCOM0
1: SSEG0
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
SLCDC2 Register
Bit
Name
7
6
5
4
3
2
1
0
SEG13EN SEG12EN SEG11EN SEG10EN SEG9EN SEG8EN SEG7EN SEG6EN
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 7SEG13EN: SSEG13 pin function select
0: Other pin-shared functions
1: SSEG13 function
Bit 6SEG12EN: SSEG12 pin function select
0: Other pin-shared functions
1: SSEG12 function
Bit 5SEG11EN: SSEG11 pin function select
0: Other pin-shared functions
1: SSEG11 function
Bit 4SEG10EN: SSEG10 pin function select
0: Other pin-shared functions
1: SSEG10 function
Bit 3SEG9EN: SSEG9 pin function select
0: Other pin-shared functions
1: SSEG9 function
Bit 2SEG8EN: SSEG8 pin function select
0: Other pin-shared functions
1: SSEG8 function
Bit 1SEG7EN: SSEG7 pin function select
0: Other pin-shared functions
1: SSEG7 function
Bit 0SEG6EN: SSEG6 pin function select
0: Other pin-shared functions
1: SSEG6 function
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
SLCDC3 Register – HT66F0175
Bit
7
6
Name
—
—
5
4
3
2
1
0
SEG19EN SEG18EN SEG17EN SEG16EN SEG15EN SEG14EN
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 5SEG19EN: SSEG19 pin function select
0: Other pin-shared functions
1: SSEG19 function
Bit 4SEG18EN: SSEG18 pin function select
0: Other pin-shared functions
1: SSEG18 function
Bit 3SEG17EN: SSEG17 pin function select
0: Other pin-shared functions
1: SSEG17 function
Bit 2SEG16EN: SSEG16 pin function select
0: Other pin-shared functions
1: SSEG16 function
Bit 1SEG15EN: SSEG15 pin function select
0: Other pin-shared functions
1: SSEG15 function
Bit 0SEG14EN: SSEG14 pin function select
0: Other pin-shared functions
1: SSEG14 function
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
SLCDC3 Register – HT66F0185
Bit
7
6
5
4
3
2
1
0
Name SEG21EN SEG20EN SEG19EN SEG18EN SEG17EN SEG16EN SEG15EN SEG14EN
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
1
0
Bit 7SEG21EN: SSEG21 pin function select
0: Other pin-shared functions
1: SSEG21 function
Bit 6SEG20EN: SSEG20 pin function select
0: Other pin-shared functions
1: SSEG20 function
Bit 5SEG19EN: SSEG19 pin function select
0: Other pin-shared functions
1: SSEG19 function
Bit 4SEG18EN: SSEG18 pin function select
0: Other pin-shared functions
1: SSEG18 function
Bit 3SEG17EN: SSEG17 pin function select
0: Other pin-shared functions
1: SSEG17 function
Bit 2SEG16EN: SSEG16 pin function select
0: Other pin-shared functions
1: SSEG16 function
Bit 1SEG15EN: SSEG15 pin function select
0: Other pin-shared functions
1: SSEG15 function
Bit 0SEG14EN: SSEG14 pin function select
0: Other pin-shared functions
1: SSEG14 function
SLCDC4 Register – HT66F0185
Bit
7
6
5
4
3
2
Name
—
—
—
—
—
—
R/W
—
—
—
—
—
—
R/W
R/W
POR
—
—
—
—
—
—
0
0
Bit 7~2
SEG23EN SEG22EN
Unimplemented, read as “0”
Bit 1SEG23EN: SSEG23 pin function select
0: Other pin-shared functions
1: SSEG23 function
Bit 0SEG22EN: SSEG22 pin function select
0: Other pin-shared functions
1: SSEG22 function
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
UART Interface
The UART interface module is only contained in the HT66F0185 device. The HT66F0185 device
contains an integrated full-duplex asynchronous serial communications UART interface that enables
communication with external devices that contain a serial interface. The UART function has many
features and can transmit and receive data serially by transferring a frame of data with eight or
nine data bits per transmission as well as being able to detect errors when the data is overwritten or
incorrectly framed. The UART function possesses its own internal interrupt which can be used to
indicate when a reception occurs or when a transmission terminates.
The integrated UART function contains the following features:
• Full-duplex, asynchronous communication
• 8 or 9 bits character length
• Even, odd or no parity options
• One or two stop bits
• Baud rate generator with 8-bit prescaler
• Parity, framing, noise and overrun error detection
• Support for interrupt on address detect (last character bit=1)
• Separately enabled transmitter and receiver
• 2-byte Deep FIFO Receive Data Buffer
• Transmit and receive interrupts
• Interrupts can be initialized by the following conditions:
♦♦
Transmitter Empty
♦♦
Transmitter Idle
♦♦
Receiver Full
♦♦
Receiver Overrun
♦♦
Address Mode Detect
T�ans�itte� Shift Registe� (TSR)
MSB
…………………………
Receive� Shift Registe� (RSR)
LSB
TX Pin
TX Registe� (TXR)
RX Pin
MSB
Data to �e t�ans�itted
LSB
RX Registe� (RXR)
Baud Rate
Gene�ato�
fSYS
…………………………
Buffe�
Data �eceived
MCU Data Bus
UART Data Transfer Block Diagram
Rev. 1.10
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November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
UART External Pin
To communicate with an external serial interface, the internal UART has two external pins known
as TX and RX. The TX and RX pins are respectively the UART transmitter and receiver pins which
are pin-shared with I/O or other pin-shared functions. Along with the UARTEN bit, the TXEN and
RXEN bits, if set, will automatically setup these I/O pins to their respective TX output and RX input
conditions and disable any pull-high resistor option which may exist on the TX and RX pins. When
the TX or RX pin function is disabled by clearing the UARTEN, TXEN or RXEN bit, the TX or RX
pin will be used as I/O or other pin-shared functional pin depending upon the pin-shared function
priority.
UART Data Transfer Scheme
The above diagram shows the overall data transfer structure arrangement for the UART interface.
The actual data to be transmitted from the MCU is first transferred to the TXR register by the
application program. The data will then be transferred to the Transmit Shift Register from where it
will be shifted out, LSB first, onto the TX pin at a rate controlled by the Baud Rate Generator. Only
the TXR register is mapped onto the MCU Data Memory, the Transmit Shift Register is not mapped
and is therefore inaccessible to the application program.
Data to be received by the UART is accepted on the external RX pin, from where it is shifted in,
LSB first, to the Receiver Shift Register at a rate controlled by the Baud Rate Generator. When
the shift register is full, the data will then be transferred from the shift register to the internal RXR
register, where it is buffered and can be manipulated by the application program. Only the TXR
register is mapped onto the MCU Data Memory, the Receiver Shift Register is not mapped and is
therefore inaccessible to the application program.
It should be noted that the actual register for data transmission and reception, although referred to
in the text, and in application programs, as separate TXR and RXR registers, only exists as a single
shared register in the Data Memory. This shared register known as the TXR_RXR register is used
for both data transmission and data reception.
UART Status and Control Registers
There are five control registers associated with the UART function. The USR, UCR1 and UCR2
registers control the overall function of the UART, while the BRG register controls the Baud rate.
The actual data to be transmitted and received on the serial interface is managed through the TXR_
RXR data registers.
Register
Name
Bit
7
6
5
4
3
2
1
0
TXIF
USR
PERR
NF
FERR
OERR
RIDLE
RXIF
TIDLE
UCR1
UARTEN
BNO
PREN
PRT
STOPS
TXBRK
RX8
TX8
UCR2
TXEN
RXEN
BRGH
ADDEN
WAKE
RIE
TIIE
TEIE
BRG
BRG7
BRG6
BRG5
BRG4
BRG3
BRG2
BRG1
BRG0
TXR_RXR
TXRX7
TXRX6
TXRX5
TXRX4
TXRX3
TXRX2
TXRX1
TXRX0
UART Status and Control Registers List – HT66F0185 only
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
TXR_RXR Register
The TXR_RXR register is the data register which is used to store the data to be transmitted on the
TX pin or being received from the RX pin.
Bit
7
6
5
4
3
2
1
0
Name
TXRX7
TXRX6
TXRX5
TXRX4
TXRX3
TXRX2
TXRX1
TXRX0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
x
x
x
x
x
x
x
x
“x”: unknown
Bit 7~0TXRX7~TXRX0: UART Transmit/Receive Data bits
USR Register
The USR register is the status register for the UART, which can be read by the program to
determine the present status of the UART. All flags within the USR register are read only and further
explanations are given below.
Bit
7
6
5
4
3
2
1
0
Name
PERR
NF
FERR
OERR
RIDLE
RXIF
TIDLE
TXIF
R/W
R
R
R
R
R
R
R
R
POR
0
0
0
0
1
0
1
1
Bit 7PERR: Parity error flag
0: No parity error is detected
1: Parity error is detected
The PERR flag is the parity error flag. When this read only flag is “0”, it indicates a
parity error has not been detected. When the flag is “1”, it indicates that the parity of
the received word is incorrect. This error flag is applicable only if Parity mode (odd or
even) is selected. The flag can also be cleared by a software sequence which involves
a read to the status register USR followed by an access to the RXR data register.
Bit 6NF: Noise flag
0: No noise is detected
1: Noise is detected
The NF flag is the noise flag. When this read only flag is “0”, it indicates no noise
condition. When the flag is “1”, it indicates that the UART has detected noise on the
receiver input. The NF flag is set during the same cycle as the RXIF flag but will not
be set in the case of as overrun. The NF flag can be cleared by a software sequence
which will involve a read to the status register USR followed by an access to the RXR
data register.
Bit 5FERR: Framing error flag
0: No framing error is detected
1: Framing error is detected
The FERR flag is the framing error flag. When this read only flag is “0”, it indicates
that there is no framing error. When the flag is “1”, it indicates that a framing error
has been detected for the current character. The flag can also be cleared by a software
sequence which will involve a read to the status register USR followed by an access to
the RXR data register.
Rev. 1.10
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November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Bit 4OERR: Overrun error flag
0: No overrun error is detected
1: Overrun error is detected
The OERR flag is the overrun error flag which indicates when the receiver buffer has
overflowed. When this read only flag is “0”, it indicates that there is no overrun error.
When the flag is “1”, it indicates that an overrun error occurs which will inhibit further
transfers to the RXR receive data register. The flag is cleared by a software sequence,
which is a read to the status register USR followed by an access to the RXR data
register.
Bit 3RIDLE: Receiver status
0: Data reception is in progress (data being received)
1: No data reception is in progress (receiver is idle)
The RIDLE flag is the receiver status flag. When this read only flag is “0”, it indicates
that the receiver is between the initial detection of the start bit and the completion of
the stop bit. When the flag is “1”, it indicates that the receiver is idle. Between the
completion of the stop bit and the detection of the next start bit, the RIDLE bit is “1”
indicating that the UART receiver is idle and the RX pin stays in logic high condition.
Bit 2RXIF: Receive RXR data register status
0: RXR data register is empty
1: RXR data register has available data
The RXIF flag is the receive data register status flag. When this read only flag is “0”,
it indicates that the RXR read data register is empty. When the flag is “1”, it indicates
that the RXR read data register contains new data. When the contents of the shift
register are transferred to the RXR register, an interrupt is generated if RIE=1 in the
UCR2 register. If one or more errors are detected in the received word, the appropriate
receive-related flags NF, FERR, and/or PERR are set within the same clock cycle. The
RXIF flag is cleared when the USR register is read with RXIF set, followed by a read
from the RXR register, and if the RXR register has no data available.
Bit 1TIDLE: Transmission status
0: Data transmission is in progress (data being transmitted)
1: No data transmission is in progress (transmitter is idle)
The TIDLE flag is known as the transmission complete flag. When this read only
flag is “0”, it indicates that a transmission is in progress. This flag will be set to “1”
when the TXIF flag is “1” and when there is no transmit data or break character being
transmitted. When TIDLE is equal to 1, the TX pin becomes idle with the pin state
in logic high condition. The TIDLE flag is cleared by reading the USR register with
TIDLE set and then writing to the TXR register. The flag is not generated when a data
character or a break is queued and ready to be sent.
Bit 0TXIF: Transmit TXR data register status
0: Character is not transferred to the transmit shift register
1: Character has transferred to the transmit shift register (TXR data register is empty)
The TXIF flag is the transmit data register empty flag. When this read only flag is “0”,
it indicates that the character is not transferred to the transmitter shift register. When
the flag is “1”, it indicates that the transmitter shift register has received a character
from the TXR data register. The TXIF flag is cleared by reading the UART status
register (USR) with TXIF set and then writing to the TXR data register. Note that
when the TXEN bit is set, the TXIF flag bit will also be set since the transmit data
register is not yet full.
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
UCR1 Register
The UCR1 register together with the UCR2 register are the UART control registers that are used
to set the various options for the UART function such as overall on/off control, parity control, data
transfer bit length, etc. Further explanation on each of the bits is given below.
Bit
7
6
5
4
3
2
1
0
Name
UARTEN
BNO
PREN
PRT
STOPS
TXBRK
RX8
TX8
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R
W
POR
0
0
0
0
0
0
x
0
“x”: unknown
Bit 7UARTEN: UART function enable control
0: Disable UART; TX and RX pins are used as other pin-shared functional pins.
1: Enable UART; TX and RX pins can function as UART pins defined by TXEN and
RXEN bits
The UARTEN bit is the UART enable bit. When this bit is equal to “0”, the UART will
be disabled and the RX pin as well as the TX pin will be other pin-shared functional
pins. When the bit is equal to “1”, the UART will be enabled and the TX and RX pins
will function as defined by the TXEN and RXEN enable control bits. When the UART
is disabled, it will empty the buffer so any character remaining in the buffer will be
discarded. In addition, the value of the baud rate counter will be reset. If the UART
is disabled, all error and status flags will be reset. Also the TXEN, RXEN, TXBRK,
RXIF, OERR, FERR, PERR and NF bits will be cleared, while the TIDLE, TXIF and
RIDLE bits will be set. Other control bits in UCR1, UCR2 and BRG registers will
remain unaffected. If the UART is active and the UARTEN bit is cleared, all pending
transmissions and receptions will be terminated and the module will be reset as defined
above. When the UART is re-enabled, it will restart in the same configuration.
Bit 6BNO: Number of data transfer bits selection
0: 8-bit data transfer
1: 9-bit data transfer
This bit is used to select the data length format, which can have a choice of either
8-bit or 9-bit format. When this bit is equal to “1”, a 9-bit data length format will be
selected. If the bit is equal to “0”, then an 8-bit data length format will be selected. If
9-bit data length format is selected, then bits RX8 and TX8 will be used to store the 9th
bit of the received and transmitted data respectively.
Bit 5PREN: Parity function enable control
0: Parity function is disabled
1: Parity function is enabled
This bit is the parity function enable bit. When this bit is equal to 1, the parity function
will be enabled. If the bit is equal to 0, then the parity function will be disabled.
Bit 4PRT: Parity type selection bit
0: Even parity for parity generator
1: Odd parity for parity generator
This bit is the parity type selection bit. When this bit is equal to 1, odd parity type will
be selected. If the bit is equal to 0, then even parity type will be selected.
Bit 3STOPS: Number of stop bits selection
0: One stop bit format is used
1: Two stop bits format is used
This bit determines if one or two stop bits are to be used. When this bit is equal to “1”,
two stop bits format are used. If the bit is equal to “0”, then only one stop bit format is
used.
Rev. 1.10
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A/D 8-Bit Flash MCU with EEPROM
Bit 2TXBRK: Transmit break character
0: No break character is transmitted
1: Break characters transmit
The TXBRK bit is the Transmit Break Character bit. When this bit is equal to “0”,
there are no break characters and the TX pin operats normally. When the bit is equal to
“1”, there are transmit break characters and the transmitter will send logic zeros. When
this bit is equal to “1”, after the buffered data has been transmitted, the transmitter
output is held low for a minimum of a 13-bit length and until the TXBRK bit is reset.
Bit 1RX8: Receive data bit 8 for 9-bit data transfer format (read only)
This bit is only used if 9-bit data transfers are used, in which case this bit location will
store the 9th bit of the received data known as RX8. The BNO bit is used to determine
whether data transfes are in 8-bit or 9-bit format.
Bit 0TX8: Transmit data bit 8 for 9-bit data transfer format (write only)
This bit is only used if 9-bit data transfers are used, in which case this bit location
will store the 9th bit of the transmitted data known as TX8. The BNO bit is used to
determine whether data transfes are in 8-bit or 9-bit format.
UCR2 Register
The UCR2 register is the second of the UART control registers and serves several purposes. One
of its main functions is to control the basic enable/disable operation if the UART Transmitter and
Receiver as well as enabling the various UART interrupt sources. The register also serves to control
the baud rate speed, receiver wake-up function enable and the address detect function enable.
Further explanation on each of the bits is given below.
Bit
7
6
5
4
3
2
1
0
Name
TXEN
RXEN
BRGH
ADDEN
WAKE
RIE
TIIE
TEIE
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 7TXEN: UART Transmitter enable control
0: UART Transmitter is disabled
1: UART Transmitter is enabled
The TXEN bit is the Transmitter Enable Bit. When this bit is equal to “0”, the
transmitter will be disabled with any pending data transmissions being aborted. In
addition the buffers will be reset. In this situation the TX pin will be other pin-shared
functional pin. If the TXEN bit is equal to “1” and the UARTEN bit is also equal to
1, the transmitter will be enabled and the TX pin will be controlled by the UART.
Clearing the TXEN bit during a transmission will cause the data transmission to be
aborted and will reset the transmitter. If this situation occurs, the TX pin will be other
pin-shared functional pin.
Bit 6RXEN: UART Receiver enable control
0: UART Receiver is disabled
1: UART Receiver is enabled
The RXEN bit is the Receiver Enable Bit. When this bit is equal to “0”, the receiver
will be disabled with any pending data receptions being aborted. In addition the
receiver buffers will be reset. In this situation the RX pin will be other pin-shared
functional pin. If the RXEN bit is equal to “1” and the UARTEN bit is also equal
to 1, the receiver will be enabled and the RX pin will be controlled by the UART.
Clearing the RXEN bit during a reception will cause the data reception to be aborted
and will reset the receiver. If this situation occurs, the RX pin will be other pin-shared
functional pin.
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Bit 5BRGH: Baud Rate speed selection
0: Low speed baud rate
1: High speed baud rate
The bit named BRGH selects the high or low speed mode of the Baud Rate Generator.
This bit, together with the value placed in the baud rate register, BRG, controls the
baud rate of the UART. If the bit is equal to 0, the low speed mode is selected.
Bit 4ADDEN: Address detect function enable control
0: Address detection function is disabled
1: Address detection function is enabled
The bit named ADDEN is the address detection function enable control bit. When this
bit is equal to 1, the address detection function is enabled. When it occurs, if the 8th
bit, which corresponds to RX7 if BNO=0, or the 9th bit, which corresponds to RX8 if
BNO=1, has a value of “1”, then the received word will be identified as an address,
rather than data. If the corresponding interrupt is enabled, an interrupt request will be
generated each time the received word has the address bit set, which is the 8th or 9th
bit depending on the value of the BNO bit. If the address bit known as the 8th or 9th
bit of the received word is “0” with the address detection function being enabled, an
interrupt will not be generated and the received data will be discarded.
Bit 3WAKE: RX pin falling edge wake-up function enable control
0: RX pin wake-up function is disabled
1: RX pin wake-up function is enabled
The bit enables or disables the receiver wake-up function. If this bit is equal to 1 and
the device is in IDLE0 or SLEEP mode, a falling edge on the RX pin will wake up the
device. If this bit is equal to 0 and the device is in the power down mode, any edge
transitions on the RX pin will not wake up the device.
Bit 2RIE: Receiver interrupt enable control
0: Receiver related interrupt is disabled
1: Receiver related interrupt is enabled
The bit enables or disables the receiver interrupt. If this bit is equal to 1 and when the
receiver overrun flag OERR or received data available flag RXIF is set, the UART
interrupt request flag will be set. If this bit is equal to 0, the UART interrupt request
flag will not be influenced by the condition of the OERR or RXIF flags.
Bit 1TIIE: Transmitter Idle interrupt enable control
0: Transmitter idle interrupt is disabled
1: Transmitter idle interrupt is enabled
The bit enables or disables the transmitter idle interrupt. If this bit is equal to 1 and
when the transmitter idle flag TIDLE is set, due to a transmitter idle condition, the
UART interrupt request flag will be set. If this bit is equal to 0, the UART interrupt
request flag will not be influenced by the condition of the TIDLE flag.
Bit 0TEIE: Transmitter Empty interrupt enable control
0: Transmitter empty interrupt is disabled
1: Transmitter empty interrupt is enabled
The bit enables or disables the transmitter empty interrupt. If this bit is equal to 1 and
when the transmitter empty flag TXIF is set, due to a transmitter empty condition, the
UART interrupt request flag will be set. If this bit is equal to 0, the UART interrupt
request flag will not be influenced by the condition of the TXIF flag.
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Baud Rate Generator
To setup the speed of the serial data communication, the UART function contains its own dedicated
baud rate generator. The baud rate is controlled by its own internal free running 8-bit counter, the
period of which is determined by two factors. The first of these is the value placed in the BRG
register and the second is the value of the BRGH bit within the UCR2 control register. The BRGH
bit decides, if the baud rate generator is to be used in a high speed mode or low speed mode, which
in turn determines the formula that is used to calculate the baud rate. The value in the BRG register,
N, which is used in the following baud rate calculation formula determines the division factor. Note
that N is the decimal value placed in the BRG register and has a range of between 0 and 255.
UCR2 BRGH Bit
0
1
Baud Rate (BR)
fSYS
[6�(�+1)]
fSYS
[16(�+1)]
By programming the BRGH bit which allows selection of the related formula and programming the
required value in the BRG register, the required baud rate can be setup. Note that because the actual
baud rate is determined using a discrete value, N, placed in the BRG register, there will be an error
associated between the actual and requested value. The following example shows how the BRG
register value N and the error value can be calculated.
BRG Register
Bit
7
6
5
4
3
2
1
0
Name
BRG7
BRG6
BRG5
BRG4
BRG3
BRG2
BRG1
BRG0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
x
x
x
x
x
x
x
x
“x”: unknown
Bit 7~0BRG7~BRG0: Baud Rate values
By programming the BRGH bit in the UCR2 register which allows selection of the
related formula described above and programming the required value in the BRG
register, the required baud rate can be setup.
Calculating the Baud Rate and Error Values
For a clock frequency of 4MHz, and with BRGH set to 0 determine the BRG register value N, the
actual baud rate and the error value for a desired baud rate of 4800.
fSYS
From the above table the desired baud rate BR =
[64(N+1)]
fSYS
Re-arranging this equation gives N =
-1
(BR×64)
4000000
Giving a value for N =
- 1 = 12.0208
(4800×64)
To obtain the closest value, a decimal value of 12 should be placed into the BRG register. This gives
4000000
an actual or calculated baud rate value of BR =
= 4808
[64(12+1)]
4808-4800
Therefore the error is equal to
= 0.16%
4800
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UART Setup and Control
For data transfer, the UART function utilizes a non-return-to-zero, more commonly known as NRZ,
format. This is composed of one start bit, eight or nine data bits and one or two stop bits. Parity
is supported by the UART hardware and can be setup to be even, odd or no parity. For the most
common data format, 8 data bits along with no parity and one stop bit, denoted as 8, N, 1, is used
as the default setting, which is the setting at power-on. The number of data bits and stop bits, along
with the parity, are setup by programming the corresponding BNO, PRT, PREN and STOPS bits in
the UCR1 register. The baud rate used to transmit and receive data is setup using the internal 8-bit
baud rate generator, while the data is transmitted and received LSB first. Although the transmitter
and receiver of the UART are functionally independent, they both use the same data format and baud
rate. In all cases stop bits will be used for data transmission.
Enabling/Disabling the UART Interface
The basic on/off function of the internal UART function is controlled using the UARTEN bit in the
UCR1 register. If the UARTEN, TXEN and RXEN bits are set, then these two UART pins will act
as normal TX output pin and RX input pin respectively. If no data is being transmitted on the TX
pin, then it will default to a logic high value.
Clearing the UARTEN bit will disable the TX and RX pins and these two pins will be used as I/
O or other pin-shared functional pins. When the UART function is disabled, the buffer will be
reset to an empty condition, at the same time discarding any remaining residual data. Disabling the
UART will also reset the enable control, the error and status flags with bits TXEN, RXEN, TXBRK,
RXIF, OERR, FERR, PERR and NF being cleared while bits TIDLE, TXIF and RIDLE will be
set. The remaining control bits in the UCR1, UCR2 and BRG registers will remain unaffected.
If the UARTEN bit in the UCR1 register is cleared while the UART is active, then all pending
transmissions and receptions will be immediately suspended and the UART will be reset to a
condition as defined above. If the UART is then subsequently re-enabled, it will restart again in the
same configuration.
Data, Parity and Stop Bit Selection
The format of the data to be transferred is composed of various factors such as data bit length,
parity on/off, parity type, address bits and the number of stop bits. These factors are determined by
the setup of various bits within the UCR1 register. The BNO bit controls the number of data bits
which can be set to either 8 or 9. The PRT bit controls the choice if odd or even parity. The PREN
bit controls the parity on/off function. The STOPS bit decides whether one or two stop bits are to
be used. The following table shows various formats for data transmission. The address detect mode
control bit identifies the frame as an address character. The number of stop bits, which can be either
one or two, is independent of the data length.
Start Bit
Data Bits
Address Bits
Parity Bit
Stop Bit
Example of 8-bit Data Formats
1
8
0
0
1
1
7
0
1
1
1
7
1
0
1
Example of 9-bit Data Formats
1
9
0
0
1
1
8
0
1
1
1
8
1
0
1
Transmitter Receiver Data Format
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The following diagram shows the transmit and receive waveforms for both 8-bit and 9-bit data
formats.
UART Transmitter
Data word lengths of either 8 or 9 bits can be selected by programming the BNO bit in the UCR1
register. When BNO bit is set, the word length will be set to 9 bits. In this case the 9th bit, which
is the MSB, needs to be stored in the TX8 bit in the UCR1 register. At the transmitter core lies the
Transmitter Shift Register, more commonly known as the TSR, whose data is obtained from the
transmit data register, which is known as the TXR register. The data to be transmitted is loaded
into this TXR register by the application program. The TSR register is not written to with new data
until the stop bit from the previous transmission has been sent out. As soon as this stop bit has been
transmitted, the TSR can then be loaded with new data from the TXR register, if it is available. It
should be noted that the TSR register, unlike many other registers, is not directly mapped into the
Data Memory area and as such is not available to the application program for direct read/write
operations. An actual transmission of data will normally be enabled when the TXEN bit is set, but
the data will not be transmitted until the TXR register has been loaded with data and the baud rate
generator has defined a shift clock source. However, the transmission can also be initiated by first
loading data into the TXR register, after which the TXEN bit can be set. When a transmission of
data begins, the TSR is normally empty, in which case a transfer to the TXR register will result in
an immediate transfer to the TSR. If during a transmission the TXEN bit is cleared, the transmission
will immediately cease and the transmitter will be reset. The TX output pin will then return to the I/
O or other pin-shared function.
Transmitting Data
When the UART is transmitting data, the data is shifted on the TX pin from the shift register, with
the least significant bit LSB first. In the transmit mode, the TXR register forms a buffer between the
internal bus and the transmitter shift register. It should be noted that if 9-bit data format has been
selected, then the MSB will be taken from the TX8 bit in the UCR1 register. The steps to initiate a
data transfer can be summarized as follows:
• Make the correct selection of the BNO, PRT, PREN and STOPS bits to define the required word
length, parity type and number of stop bits.
• Setup the BRG register to select the desired baud rate.
• Set the TXEN bit to ensure that the UART transmitter is enabled and the TX pin is used as a
UART transmitter pin.
• Access the USR register and write the data that is to be transmitted into the TXR register. Note
that this step will clear the TXIF bit.
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This sequence of events can now be repeated to send additional data. It should be noted that when
TXIF=0, data will be inhibited from being written to the TXR register. Clearing the TXIF flag is
always achieved using the following software sequence:
1. A USR register access
2. A TXR register write execution
The read-only TXIF flag is set by the UART hardware and if set indicates that the TXR register is
empty and that other data can now be written into the TXR register without overwriting the previous
data. If the TEIE bit is set, then the TXIF flag will generate an interrupt. During a data transmission,
a write instruction to the TXR register will place the data into the TXR register, which will be
copied to the shift register at the end of the present transmission. When there is no data transmission
in progress, a write instruction to the TXR register will place the data directly into the shift register,
resulting in the commencement of data transmission, and the TXIF bit being immediately set. When
a frame transmission is complete, which happens after stop bits are sent or after the break frame, the
TIDLE bit will be set. To clear the TIDLE bit the following software sequence is used:
1. A USR register access
2. A TXR register write execution
Note that both the TXIF and TIDLE bits are cleared by the same software sequence.
Transmitting Break
If the TXBRK bit is set, then the break characters will be sent on the next transmission. Break
character transmission consists of a start bit, followed by 13xN “0” bits, where N=1, 2, etc. If a
break character is to be transmitted, then the TXBRK bit must be first set by the application program
and then cleared to generate the stop bits. Transmitting a break character will not generate a transmit
interrupt. Note that a break condition length is at least 13 bits long. If the TXBRK bit is continually
kept at a logic high level, then the transmitter circuitry will transmit continuous break characters.
After the application program has cleared the TXBRK bit, the transmitter will finish transmitting the
last break character and subsequently send out one or two stop bits. The automatic logic high at the
end of the last break character will ensure that the start bit of the next frame is recognized.
UART Receiver
The UART is capable of receiving word lengths of either 8 or 9 bits can be selected by programming
the BNO bit in the UCR1 register. When BNO bit is set, the word length will be set to 9 bits. In
this case the 9th bit, which is the MSB, will be stored in the RX8 bit in the UCR1 register. At the
receiver core lies the Receiver Shift Register more commonly known as the RSR. The data which
is received on the RX external input pin is sent to the data recovery block. The data recovery block
operating speed is 16 times that of the baud rate, while the main receive serial shifter operates at the
baud rate. After the RX pin is sampled for the stop bit, the received data in RSR is transferred to the
receive data register, if the register is empty. The data which is received on the external RX input pin
is sampled three times by a majority detect circuit to determine the logic level that has been placed
onto the RX pin. It should be noted that the RSR register, unlike many other registers, is not directly
mapped into the Data Memory area and as such is not available to the application program for direct
read/write operations.
Receiving Data
When the UART receiver is receiving data, the data is serially shifted in on the external RX input
pin to the shift register, with the least significant bit LSB first. The RXR register is a two byte deep
FIFO data buffer, where two bytes can be held in the FIFO while the 3rd byte can continue to be
received. Note that the application program must ensure that the data is read from RXR before the
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3rd byte has been completely shifted in, otherwise the 3rd byte will be discarded and an overrun error
OERR will be subsequently indicated. The steps to initiate a data transfer can be summarized as
follows:
• Make the correct selection of the BNO, PRT, PREN and STOPS bits to define the required word
length, parity type and number of stop bits.
• Setup the BRG register to select the desired baud rate.
• Set the RXEN bit to ensure that the UART receiver is enabled and the RX pin is used as a UART
receiver pin.
At this point the receiver will be enabled which will begin to look for a start bit.
When a character is received, the following sequence of events will occur:
• The RXIF bit in the USR register will be set then RXR register has data available, at least one
more character can be read.
• When the contents of the shift register have been transferred to the RXR register and if the RIE
bit is set, then an interrupt will be generated.
• If during reception, a frame error, noise error, parity error or an overrun error has been detected,
then the error flags can be set.
The RXIF bit can be cleared using the following software sequence:
1. A USR register access
2. A RXR register read execution
Receiving Break
Any break character received by the UART will be managed as a framing error. The receiver will
count and expect a certain number of bit times as specified by the values programmed into the BNO
and STOPS bits. If the break is much longer than 13 bit times, the reception will be considered as
complete after the number of bit times specified by BNO and STOPS. The RXIF bit is set, FERR
is set, zeros are loaded into the receive data register, interrupts are generated if appropriate and the
RIDLE bit is set. If a long break signal has been detected and the receiver has received a start bit,
the data bits and the invalid stop bit, which sets the FERR flag, the receiver must wait for a valid
stop bit before looking for the next start bit. The receiver will not make the assumption that the
break condition on the line is the next start bit. A break is regarded as a character that contains only
zeros with the FERR flag set. The break character will be loaded into the buffer and no further data
will be received until stop bits are received. It should be noted that the RIDLE read only flag will go
high when the stop bits have not yet been received. The reception of a break character on the UART
registers will result in the following:
• The framing error flag, FERR, will be set.
• The receive data register, RXR, will be cleared.
• The OERR, NF, PERR, RIDLE or RXIF flags will possibly be set.
Idle Status
When the receiver is reading data, which means it will be in between the detection of a start bit and
the reading of a stop bit, the receiver status flag in the USR register, otherwise known as the RIDLE
flag, will have a zero value. In between the reception of a stop bit and the detection of the next start
bit, the RIDLE flag will have a high value, which indicates the receiver is in an idle condition.
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Receiver Interrupt
The read only receive interrupt flag, RXIF, in the USR register is set by an edge generated by the
receiver. An interrupt is generated if RIE=1, when a word is transferred from the Receive Shift
Register, RSR, to the Receive Data Register, RXR. An overrun error can also generate an interrupt if
RIE=1.
Managing Receiver Errors
Several types of reception errors can occur within the UART module, the following section describes
the various types and how they are managed by the UART.
Overrun Error – OERR
The RXR register is composed of a two byte deep FIFO data buffer, where two bytes can be held in
the FIFO register, while a 3th byte can continue to be received. Before the 3th byte has been entirely
shifted in, the data should be read from the RXR register. If this is not done, the overrun error flag
OERR will be consequently indicated.
In the event of an overrun error occurring, the following will happen:
• The OERR flag in the USR register will be set.
• The RXR contents will not be lost.
• The shift register will be overwritten.
• An interrupt will be generated if the RIE bit is set.
The OERR flag can be cleared by an access to the USR register followed by a read to the RXR
register.
Noise Error – NF
Over-sampling is used for data recovery to identify valid incoming data and noise. If noise is
detected within a frame, the following will occur:
• The read only noise flag, NF, in the USR register will be set on the rising edge of the RXIF bit.
• Data will be transferred from the shift register to the RXR register.
• No interrupt will be generated. However this bit rises at the same time as the RXIF bit which
itself generates an interrupt.
Note that the NF flag is reset by a USR register read operation followed by an RXR register read
operation.
Framing Error – FERR
The read only framing error flag, FERR, in the USR register, is set if a zero is detected instead of
stop bits. If two stop bits are selected, both stop bits must be high. Otherwise the FERR flag will be
set. The FERR flag is buffered along with the received data and is cleared in any reset.
Parity Error – PERR
The read only parity error flag, PERR, in the USR register, is set if the parity of the received word
is incorrect. This error flag is only applicable if the parity function is enabled, PREN=1, and if the
parity type, odd or even, is selected. The read only PERR flag is buffered along with the received
data bytes. It is cleared on any reset, it should be noted that the FERR and PERR flags are buffered
along with the corresponding word and should be read before reading the data word.
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UART Interrupt Structure
Several individual UART conditions can generate a UART interrupt. When these conditions exist,
a low pulse will be generated to get the attention of the microcontroller. These conditions are a
transmitter data register empty, transmitter idle, receiver data available, receiver overrun, address
detect and an RX pin wake-up. When any of these conditions are created, if its corresponding
interrupt control is enabled and the stack is not full, the program will jump to its corresponding
interrupt vector where it can be serviced before returning to the main program. Four of these
conditions have the corresponding USR register flags which will generate a UART interrupt if its
associated interrupt enable control bit in the UCR2 register is set. The two transmitter interrupt
conditions have their own corresponding enable control bits, while the two receiver interrupt
conditions have a shared enable control bit. These enable bits can be used to mask out individual
UART interrupt sources.
The address detect condition, which is also a UART interrupt source, does not have an associated
flag, but will generate a UART interrupt when an address detect condition occurs if its function
is enabled by setting the ADDEN bit in the UCR2 register. An RX pin wake-up, which is also a
UART interrupt source, does not have an associated flag, but will generate a UART interrupt if the
microcontroller is woken up from IDLE0 or SLEEP mode by a falling edge on the RX pin, if the
WAKE and RIE bits in the UCR2 register are set. Note that in the event of an RX wake-up interrupt
occurring, there will be a certain period of delay, commonly known as the System Start-up Time, for
the oscillator to restart and stabilize before the system resumes normal operation.
Note that the USR register flags are read only and cannot be cleared or set by the application
program, neither will they be cleared when the program jumps to the corresponding interrupt
servicing routine, as is the case for some of the other interrupts. The flags will be cleared
automatically when certain actions are taken by the UART, the details of which are given in the
UART register section. The overall UART interrupt can be disabled or enabled by the related
interrupt enable control bits in the interrupt control registers of the microcontroller to decide whether
the interrupt requested by the UART module is masked out or allowed.
USR Registe�
UCR� Registe�
T�ans�itte� E�pty Flag TXIF
TEIE
T�ans�itte� Idle Flag TIDLE
TIIE
1
RIE
OR
Receive� Data Availa�le
RXIF
WAKE
0
1
Receive� Ove��un Flag
OERR
RX Pin
Wake-up
0
ADDEN
0
URE
0
1
EMI
0
1
Inte��upt
signal to MCU
1
0
1
0
UART Inte��upt
Request Flag
URF
0
1
RX7 if B�O=0
RX8 if B�O=1
1
UCR� Registe�
UART Interrupt Structure
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Address Detect Mode
Setting the Address Detect function enable control bit, ADDEN, in the UCR2 register, enables this
special function. If this bit is set to 1, then an additional qualifier will be placed on the generation
of a Receiver Data Available interrupt, which is requested by the RXIF flag. If the ADDEN bit
is equal to 1, then when the data is available, an interrupt will only be generated, if the highest
received bit has a high value. Note that the related interrupt enable control bit and the EMI bit of the
microcontroller must also be enabled for correct interrupt generation. The highest address bit is the
9th bit if the bit BNO=1 or the 8th bit if the bit BNO=0. If the highest bit is high, then the received
word will be defined as an address rather than data. A Data Available interrupt will be generated
every time the last bit of the received word is set. If the ADDEN bit is equal to 0, then a Receive
Data Available interrupt will be generated each time the RXIF flag is set, irrespective of the data last
but status. The address detection and parity functions are mutually exclusive functions. Therefore, if
the address detect function is enabled, then to ensure correct operation, the parity function should be
disabled by resetting the parity function enable bit PREN to zero.
ADDEN
Bit 9 if BNO=1
Bit 8 if BNO=0
UART Interrupt
Generated
0
√
0
1
1
√
0
X
1
√
ADDEN Bit Function
UART Power Down and Wake-up
When the MCU system clock is switched off, the UART will cease to function. If the MCU executes
the “HALT” instruction and switches off the system clock while a transmission is still in progress,
then the transmission will be paused until the UART clock source derived from the microcontroller
is activated. In a similar way, if the MCU executes the “HALT” instruction and switches off the
system clock while receiving data, then the reception of data will likewise be paused. When the
MCU enters the IDLE or SLEEP Mode, note that the USR, UCR1, UCR2, transmit and receive
registers, as well as the BRG register will not be affected. It is recommended to make sure first that
the UART data transmission or reception has been finished before the microcontroller enters the
power down mode.
The UART function contains a receiver RX pin wake-up function, which is enabled or disabled
by the WAKE bit in the UCR2 register. If this bit, along with the UART enable bit, UARTEN, the
receiver enable bit, RXEN and the receiver interrupt bit, RIE, are all set before the MCU enters the
IDLE0 or SLEEP Mode, then a falling edge on the RX pin will wake up the MCU from the IDLE0
or SLEEP Mode. Note that as it takes certain system clock cycles after a wake-up, before normal
microcontroller operation resumes, any data received during this time on the RX pin will be ignored.
For a UART wake-up interrupt to occur, in addition to the bits for the wake-up being set, the global
interrupt enable bit, EMI, and the UART interrupt enable bit, URE, must be set. If the EMI and URE
bits are not set then only a wake up event will occur and no interrupt will be generated. Note also
that as it takes certain system clock cycles after a wake-up before normal microcontroller resumes,
the UART interrupt will not be generated until after this time has elapsed.
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Low Voltage Detector – LVD
Each device has a Low Voltage Detector function, also known as LVD. This enabled the device to
monitor the power supply voltage, VDD, and provide a warning signal should it fall below a certain
level. This function may be especially useful in battery applications where the supply voltage will
gradually reduce as the battery ages, as it allows an early warning battery low signal to be generated.
The Low Voltage Detector also has the capability of generating an interrupt signal.
LVD Register
The Low Voltage Detector function is controlled using a single register with the name LVDC. Three
bits in this register, VLVD2~VLVD0, are used to select one of eight fixed voltages below which
a low voltage condition will be determined. A low voltage condition is indicated when the LVDO
bit is set. If the LVDO bit is low, this indicates that the VDD voltage is above the preset low voltage
value. The LVDEN bit is used to control the overall on/off function of the low voltage detector.
Setting the bit high will enable the low voltage detector. Clearing the bit to zero will switch off the
internal low voltage detector circuits. As the low voltage detector will consume a certain amount of
power, it may be desirable to switch off the circuit when not in use, an important consideration in
power sensitive battery powered applications.
LVDC Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
LVDO
LVDEN
—
VLVD2
VLVD1
VLVD0
R/W
—
—
R
R/W
—
R/W
R/W
R/W
POR
—
—
0
0
—
0
0
0
Bit 7~6
Unimplemented, read as “0”
Bit 5LVDO: LVD output flag
0: No Low Voltage Detected
1: Low Voltage Detected
Bit 4LVDEN: Low Voltage Detector Enable control
0: Disable
1: Enable
Bit 3
Unimplemented, read as “0”
Bit 2~0VLVD2~VLVD0: LVD Voltage selection
000: 2.0V
001: 2.2V
010: 2.4V
011: 2.7V
100: 3.0V
101: 3.3V
110: 3.6V
111: 4.0V
Rev. 1.10
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A/D 8-Bit Flash MCU with EEPROM
LVD Operation
The Low Voltage Detector function operates by comparing the power supply voltage, VDD, with a
pre-specified voltage level stored in the LVDC register. This has a range of between 2.0V and 4.0V.
When the power supply voltage, VDD, falls below this pre-determined value, the LVDO bit will be
set high indicating a low power supply voltage condition. The Low Voltage Detector function is
supplied by a reference voltage which will be automatically enabled. When the device is powered
down the low voltage detector will remain active if the LVDEN bit is high. After enabling the Low
Voltage Detector, a time delay tLVDS should be allowed for the circuitry to stabilise before reading the
LVDO bit. Note also that as the VDD voltage may rise and fall rather slowly, at the voltage nears that
of VLVD, there may be multiple bit LVDO transitions.
LVD Operation
The Low Voltage Detector also has its own interrupt which is contained within one of the Multifunction interrupts, providing an alternative means of low voltage detection, in addition to polling
the LVDO bit. The interrupt will only be generated after a delay of tLVD after the LVDO bit has been
set high by a low voltage condition. When the device is powered down the Low Voltage Detector
will remain active if the LVDEN bit is high. In this case, the LVF interrupt request flag will be set,
causing an interrupt to be generated if VDD falls below the preset LVD voltage. This will cause the
device to wake-up from the SLEEP or IDLE Mode, however if the Low Voltage Detector wake up
function is not required then the LVF flag should be first set high before the device enters the SLEEP
or IDLE Mode.
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A/D 8-Bit Flash MCU with EEPROM
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. These devices contain several external
interrupt and internal interrupts functions. The external interrupts are generated by the action of
the external INT0 and INT1 pins, while the internal interrupts are generated by various internal
functions such as the TMs, Time Base, LVD, EEPROM, SIM, UART and the A/D converter, etc.
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~INTC2 registers which setup the primary interrupts, the second
is the MFI0~MFI2 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 interrupts 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
Global
Request Flag
Notes
EMI
—
—
INTn Pins
INTnE
INTnF
n=0~1
Multi-function
MFnE
MFnF
n = 0~2
A/D Converter
ADE
ADF
—
Time Base
TBnE
TBnF
n=0~1
SIM
SIME
SIMF
—
—
LVD
LVE
LVF
EEPROM write operation
DEE
DEF
—
TnPE
TnPF
n = 0~1
TnAE
TnAF
n = 0~1
TM
Interrupt Register Bit Naming Conventions – HT66F0175
Function
Global
INTn Pins
Comparator
Multi-function
Enable Bit
Request Flag
EMI
—
Notes
—
INTnE
INTnF
n=0~1
CPE
CPF
—
MFnE
MFnF
n = 0~2
A/D Converter
ADE
ADF
—
Time Base
TBnE
TBnF
n=0~1
SIM
SIME
SIMF
—
UART
URE
URF
—
LVD
LVE
LVF
—
EEPROM write operation
TM
DEE
DEF
—
TnPE
TnPF
n = 0~2
TnAE
TnAF
n = 0~2
Interrupt Register Bit Naming Conventions – HT66F0185
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Bit
Register
Name
7
INTEG
—
—
INTC0
—
MF0F
INTC1
TB0F
ADF
MF2F
INTC2
—
SIMF
INT1F
MFI0
—
—
T0AF
MFI1
—
—
T1AF
MFI2
—
—
DEF
6
5
4
3
2
1
0
—
—
INT1S1
INT1S0
INT0S1
INT0S0
—
INT0F
MF0E
—
INT0E
EMI
MF1F
TB0E
ADE
MF2E
MF1E
TB1F
—
SIME
INT1E
TB1E
T0PF
—
—
T0AE
T0PE
T1PF
—
—
T1AE
T1PE
LVF
—
—
DEE
LVE
Interrupt Registers List – HT66F0175
Bit
Register
Name
7
6
5
4
3
2
1
0
INTEG
—
—
—
—
INT1S1
INT1S0
INT0S1
INT0S0
INTC0
—
MF0F
CPF
INT0F
MF0E
CPE
INT0E
EMI
INTC1
TB0F
ADF
MF2F
MF1F
TB0E
ADE
MF2E
MF1E
INTC2
URF
SIMF
INT1F
TB1F
URE
SIME
INT1E
TB1E
MFI0
—
—
T0AF
T0PF
—
—
T0AE
T0PE
MFI1
T2AF
T2PF
T1AF
T1PF
T2AE
T2PE
T1AE
T1PE
MFI2
—
—
DEF
LVF
—
—
DEE
LVE
Interrupt Registers List – HT66F0185
INTEG Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
INT1S1
INT1S0
INT0S1
INT0S0
R/W
—
—
—
—
R/W
R/W
R/W
R/W
POR
—
—
—
—
0
0
0
0
Bit 7~4
Unimplemented, read as “0”
Bit 3~2INT1S1~INT1S0: Interrupt edge control for INT1 pin
00: Disable
01: Rising edge
10: Falling edge
11: Rising and falling edges
Bit 1~0INT0S1~INT0S0: Interrupt edge control for INT0 pin
00: Disable
01: Rising edge
10: Falling edge
11: Rising and falling edges
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
INTC0 Register – HT66F0175
Bit
7
6
5
4
3
2
1
0
Name
—
MF0F
—
INT0F
MF0E
—
INT0E
EMI
R/W
—
R/W
—
R/W
R/W
—
R/W
R/W
POR
—
0
—
0
0
—
0
0
Bit 7
Unimplemented, read as “0”
Bit 6MF0F: Multi-function 0 interrupt request flag
0: No request
1: Interrupt request
Bit 5
Unimplemented, read as “0”
Bit 4INT0F: INT0 interrupt request flag
0: No request
1: Interrupt request
Bit 3MF0E: Multi-function 0 interrupt control
0: Disable
1: Enable
Bit 2
Unimplemented, read as “0”
Bit 1INT0E: INT0 interrupt control
0: Disable
1: Enable
Bit 0EMI: Global interrupt control
0: Disable
1: Enable
INTC0 Register – HT66F0185
Bit
7
6
5
4
3
2
1
0
Name
—
MF0F
CPF
INT0F
MF0E
CPE
INT0E
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 6MF0F: Multi-function 0 interrupt request flag
0: No request
1: Interrupt request
Bit 5CPF: Comparator interrupt request flag
0: No request
1: Interrupt request
Bit 4INT0F: INT0 interrupt request flag
0: no request
1: interrupt request
Bit 3MF0E: Multi-function 0 interrupt control
0: Disable
1: Enable
Bit 2CPE: Comparator interrupt control
0: Disable
1: Enable
Bit 1INT0E: INT0 interrupt control
0: Disable
1: Enable
Bit 0EMI: Global interrupt control
0: Disable
1: Enable
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
INTC1 Register
Bit
7
6
5
4
3
2
1
0
Name
TB0F
ADF
MF2F
MF1F
TB0E
ADE
MF2E
MF1E
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 7TB0F: Time Base 0 interrupt request flag
0: No request
1: Interrupt request
Bit 6ADF: A/D Converter interrupt request flag
0: No request
1: Interrupt request
Bit 5MF2F: Multi-function 2 interrupt request flag
0: No request
1: Interrupt request
Bit 4MF1F: Multi-function 1 interrupt request flag
0: No request
1: Interrupt request
Bit 3TB0E: Time Base 0 interrupt control
0: Disable
1: Enable
Bit 2ADE: A/D Converter interrupt control
0: Disable
1: Enable
Bit 1MF2E: Multi-function 2 interrupt control
0: Disable
1: Enable
Bit 0MF1E: Multi-function 1 interrupt control
0: Disable
1: Enable
Rev. 1.10
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A/D 8-Bit Flash MCU with EEPROM
INTC2 Register – HT66F0175
Bit
7
6
5
4
3
2
1
0
Name
—
SIMF
INT1F
TB1F
—
SIME
INT1E
TB1E
R/W
—
R/W
R/W
R/W
—
R/W
R/W
R/W
POR
—
0
0
0
—
0
0
0
Bit 7
Unimplemented, read as “0”
Bit 6SIMF: SIM interrupt request flag
0: No request
1: Interrupt request
Bit 5INT1F: INT1 interrupt request flag
0: No request
1: Interrupt request
Bit 4TB1F: Time Base 1 interrupt request flag
0: No request
1: Interrupt request
Bit 3
Unimplemented, read as “0”
Bit 2SIME: SIM interrupt control
0: Disable
1: Enable
Bit 1INT1E: INT1 interrupt control
0: Disable
1: Enable
Bit 0TB1E: Time Base 1 interrupt control
0: Disable
1: Enable
Rev. 1.10
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A/D 8-Bit Flash MCU with EEPROM
INTC2 Register – HT66F0185
Bit
7
6
5
4
3
2
1
0
Name
URF
SIMF
INT1F
TB1F
URE
SIME
INT1E
TB1E
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 7URF: UART interrupt request flag
0: No request
1: Interrupt request
Bit 6SIMF: SIM interrupt request flag
0: No request
1: Interrupt request
Bit 5INT1F: INT1 interrupt request flag
0: No request
1: Interrupt request
Bit 4TB1F: Time Base 1 interrupt request flag
0: No request
1: Interrupt request
Bit 3URE: UART interrupt control
0: Disable
1: Enable
Bit 2SIME: SIM interrupt control
0: Disable
1: Enable
Bit 1INT1E: INT1 interrupt control
0: Disable
1: Enable
Bit 0TB1E: Time Base 1 interrupt control
0: Disable
1: Enable
MFI0 Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
T0AF
T0PF
—
—
T0AE
T0PE
R/W
—
—
R/W
R/W
—
—
R/W
R/W
POR
—
—
0
0
—
—
0
0
Bit 7~6
Unimplemented, read as “0”
Bit 5T0AF: TM0 Comparator A match Interrupt request flag
0: No request
1: Interrupt request
Bit 4T0PF: TM0 Comparator P match Interrupt request flag
0: No request
1: Interrupt request
Bit 3~2
Unimplemented, read as “0”
Bit 1T0AE: TM0 Comparator A match Interrupt control
0: Disable
1: Enable
Bit 0T0PE: TM0 Comparator P match Interrupt control
0: Disable
1: Enable
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A/D 8-Bit Flash MCU with EEPROM
MFI1 Register – HT66F0175
Bit
7
6
5
4
3
2
1
0
Name
—
—
T1AF
T1PF
—
—
T1AE
T1PE
R/W
—
—
R/W
R/W
—
—
R/W
R/W
POR
—
—
0
0
—
—
0
0
Bit 7~6
Unimplemented, read as “0”
Bit 5T1AF: TM1 Comparator A match Interrupt request flag
0: No request
1: Interrupt request
Bit 4T1PF: TM1 Comparator P match Interrupt request flag
0: No request
1: Interrupt request
Bit 3~2
Unimplemented, read as “0”
Bit 1T1AE: TM1 Comparator A match Interrupt control
0: Disable
1: Enable
Bit 0T1PE: TM1 Comparator P match Interrupt control
0: Disable
1: Enable
MFI1 Register – HT66F0185
Bit
7
6
5
4
3
2
1
0
Name
T2AF
T2PF
T1AF
T1PF
T2AE
T2PE
T1AE
T1PE
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 7T2AF: TM2 Comparator A match Interrupt request flag
0: No request
1: Interrupt request
Bit 6T2PF: TM2 Comparator P match Interrupt request flag
0: No request
1: Interrupt request
Bit 5T1AF: TM1 Comparator A match Interrupt request flag
0: No request
1: Interrupt request
Bit 4T1PF: TM1 Comparator P match Interrupt request flag
0: No request
1: Interrupt request
Bit 3T2AE: TM2 Comparator A match Interrupt control
0: Disable
1: Enable
Bit 2T2PE: TM2 Comparator P match Interrupt control
0: Disable
1: Enable
Bit 1T1AE: TM1 Comparator A match Interrupt control
0: Disable
1: Enable
Bit 0T1PE: TM1 Comparator P match Interrupt control
0: Disable
1: Enable
Rev. 1.10
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HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
MFI2 Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
DEF
LVF
—
—
DEE
LVE
R/W
—
—
R/W
R/W
—
—
R/W
R/W
POR
—
—
0
0
—
—
0
0
Bit 7~6
Unimplemented, read as “0”
Bit 5DEF: Data EEPROM Interrupt request flag
0: No request
1: Interrupt request
Bit 4LVF: LVD Interrupt request flag
0: No request
1: Interrupt request
Bit 3~2
Unimplemented, read as “0”
Bit 1DEE: Data EEPROM Interrupt control
0: Disable
1: Enable
Bit 0LVE: LVD 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 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 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.
Rev. 1.10
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HT66F0175/HT66F0185
A/D 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.
Legend
xxF
Request Flag� no auto �eset in ISR
xxF
Request Flag� auto �eset in ISR
xxE
Ena�le Bits
TM0 P
T0PF
T0PE
TM0 A
T0AF
T0AE
TM1 P
T1PF
T1PE
TM1 A
T1AF
T1AE
LVD
LVF
LVE
EEPROM
DEF
DEE
Inte��upts contained within
Multi-Function Inte��upts
EMI auto disa�led in ISR
Inte��upt
�a�e
Request
Flags
Ena�le
Bits
Maste�
Ena�le
I�T0 Pin
I�T0F
I�T0E
EMI
0�H
M. Funct. 0
MF0F
MF0E
EMI
0CH
M. Funct. 1
MF1F
MF1E
EMI
10H
M. Funct. �
MF�F
MF�E
EMI
1�H
A/D
ADF
ADE
EMI
18H
Ti�e Base 0
TB0F
TB0E
EMI
1CH
Ti�e Base 1
TB1F
TB1E
EMI
�0H
I�T1 Pin
I�T1F
I�T1E
EMI
��H
SIM
SIMF
SIME
EMI
�8H
Vector P�io�ity
High
Low
Interrupt Scheme – HT66F0175
EMI auto disa�led in ISR
Legend
xxF
Request Flag� no auto �eset in ISR
xxF
Request Flag� auto �eset in ISR
xxE
Ena�le Bits
Inte��upts contained within
Multi-Function Inte��upts
TM0 P
T0PF
T0PE
TM0 A
T0AF
T0AE
TM1 P
T1PF
T1PE
TM1 A
T1AF
T1AE
TM� P
T�PF
T�PE
TM� A
T�AF
T�AE
LVD
LVF
LVE
EEPROM
DEF
DEE
Inte��upt
�a�e
Request
Flags
Ena�le
Bits
Maste�
Ena�le
I�T0 Pin
I�T0F
I�T0E
EMI
0�H
Co�pa�ato�
CPF
CPE
EMI
08H
M. Funct. 0
MF0F
MF0E
EMI
0CH
M. Funct. 1
MF1F
MF1E
EMI
10H
M. Funct. �
MF�F
MF�E
EMI
1�H
A/D
ADF
ADE
EMI
18H
Ti�e Base 0
TB0F
TB0E
EMI
1CH
Ti�e Base 1
TB1F
TB1E
EMI
�0H
I�T1 Pin
I�T1F
I�T1E
EMI
��H
SIM
SIMF
SIME
EMI
�8H
UART
URF
URE
EMI
�CH
Vector P�io�ity
High
Low
Interrupt Scheme – HT66F0185
Rev. 1.10
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A/D 8-Bit Flash MCU with EEPROM
External Interrupt
The external interrupts are controlled by signal transitions on the pins INT0~INT1. An external
interrupt request will take place when the external interrupt request flags, INT0F~INT1F, are set,
which will occur when a transition, whose type is chosen by the edge select bits, appears on the
external interrupt pins. To allow the program to branch to its respective interrupt vector address,
the global interrupt enable bit, EMI, and respective external interrupt enable bit, INT0E~INT1E,
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 pins are pin-shared with I/O pins, they can only be configured as external interrupt pins if
their external interrupt enable bit in the corresponding interrupt register has been set and the external
interrupt pin is selected by the corresponding pin-shared function selection bits. 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 flags, INT0F~INT1F, will be automatically reset and the EMI bit will be
automatically cleared to disable other interrupts. Note that any pull-high resistor selections on the
external interrupt pins 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.
Comparator Interrupt – HT66F0185
The comparator interrupt is controlled by the internal comparator. A comparator interrupt request
will take place when the comparator interrupt request flag, CPF, is set, a situation that will occur
when the comparator output changes state. To allow the program to branch to its respective interrupt
vector address, the global interrupt enable bit, EMI, and comparator interrupt enable bit, CPE, must
first be set. When the interrupt is enabled, the stack is not full and the comparator inputs generate
a comparator output transition, a subroutine call to the comparator interrupt vector, will take place.
When the interrupt is serviced, the comparator interrupt request flag, will be automatically reset and
the EMI bit will be automatically cleared to disable other interrupts.
Multi-function Interrupt
Within the device there are up to three 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, LVD interrupt and EEPROM write operation interrupt.
A Multi-function interrupt request will take place when any of the Multi-function interrupt request
flags MFnF 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 request flags will be
automatically reset when the interrupt is serviced, the request flags from the original source of
the Multi-function interrupts will not be automatically reset and must be manually reset by the
application program.
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A/D Converter 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 Interrupt
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.
fTBC
fSYS/�
P�escale�
M
U
X
TBCK
fTB
fTB/�8 ~ fTB/�15
M
U
X
Ti�e Base 0 Inte��upt
TB0�~TB00
P�escale�
fTB/�1� ~ fTB/�15
M
U
X
Ti�e Base 1 Inte��upt
TB11~TB10
Time Base Interrupts
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TB0C Register
Bit
7
6
5
4
3
2
1
0
Name
TBON
TBCK
TB11
TB10
LXTLP
TB02
TB01
TB00
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
1
1
0
1
1
1
Bit 7TBON: Time Base function enable control
0: Disable
1: Enable
Bit 6TBCK: Time Base clock source select
0: fTBC
1: fSYS/4
Bit 5~4TB11~TB10: Time Base 1 time-out period selection
00: 212/fTB
01: 213/fTB
10: 214/fTB
11: 215/fTB
Bit 3LXTLP: LXT Low Power control
0: Disable – LXT quick start-up
1: Enable – LXT slow start-up
Bit 2~0TB02~TB00: Time Base 0 time-out period selection
000: 28/fTB
001: 29/fTB
010: 210/fTB
011: 211/fTB
100: 212/fTB
101: 213/fTB
110: 214/fTB
111: 215/fTB
Serial Interface Module Interrupt
The Serial Interface Module Interrupt, also known as the SIM interrupt, is controlled by the SPI or
I2C data transfer. A SIM Interrupt request will take place when the SIM Interrupt request flag, SIMF,
is set, which occurs when a byte of data has been received or transmitted by the SIM interface,
an I2C slave address match or I2C bus time-out occurrence. To allow the program to branch to its
respective interrupt vector address, the global interrupt enable bit, EMI and the Serial Interface
Interrupt enable bit, SIME, must first be set. When the interrupt is enabled, the stack is not full and
any of the above described situations occurs, a subroutine call to the respective SIM Interrupt vector,
will take place. When the Serial Interface Interrupt is serviced, the EMI bit will be automatically
cleared to disable other interrupts. The SIMF flag will also be automatically cleared.
UART Transfer Interrupt – HT66F0185
The UART Transfer Interrupt is controlled by several UART transfer conditions. When one of these
conditions occurs, an interrupt pulse will be generated to get the attention of the microcontroller.
These conditions are a transmitter data register empty, transmitter idle, receiver data available,
receiver overrun, address detect and an RX pin wake-up. To allow the program to branch to its
respective interrupt vector address, the global interrupt enable bit, EMI, and UART Interrupt
enable bit, URE, must first be set. When the interrupt is enabled, the stack is not full and any of the
conditions described above occurs, a subroutine call to the UART Interrupt vector, will take place.
When the interrupt is serviced, the UART Interrupt flag, URF, will be automatically cleared. The
EMI bit will also be automatically cleared to disable other interrupts.
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LVD Interrupt
The Low Voltage Detector Interrupt is contained within the Multi-function Interrupt. An LVD
Interrupt request will take place when the LVD Interrupt request flag, LVF, is set, which occurs
when the Low Voltage Detector function detects a low power supply voltage. To allow the program
to branch to its respective interrupt vector address, the global interrupt enable bit, EMI, Low Voltage
Interrupt enable bit, LVE, and associated Multi-function interrupt enable bit, must first be set. When
the interrupt is enabled, the stack is not full and a low voltage condition occurs, a subroutine call to
the Multi-function Interrupt vector, will take place. When the Low Voltage Interrupt is serviced, the
EMI bit will be automatically cleared to disable other interrupts. However, only the Multi-function
interrupt request flag will be also automatically cleared. As the LVF flag will not be automatically
cleared, it has to be cleared by the application program.
EEPROM Interrupt
The EEPROM Write Interrupt is contained within the Multi-function Interrupt. An EEPROM
Write Interrupt request will take place when the EEPROM Write 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, EEPROM Write Interrupt enable bit,
DEE, and associated Multi-function interrupt enable bit 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
Multi-function Interrupt vector will take place. When the EEPROM Write Interrupt is serviced, the
EMI bit will be automatically cleared to disable other interrupts. However, only the Multi-function
interrupt request flag will be automatically cleared. As the DEF flag will not be automatically
cleared, it has to be cleared by the application program.
TM Interrupt
The Compact, Standard and Periodic TMs have two interrupts, one comes from the comparator A
match situation and the other comes from the comparator P match situation. All of the TM interrupts
are contained within the Multi-function Interrupts. For all of the TM types there are two interrupt
request flags and two enable control bits. 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 A match situation
happens.
To allow the program to branch to its respective interrupt vector address, the global interrupt enable
bit, EMI, respective TM Interrupt enable bit, and relevant Multi-function Interrupt enable bit, MFnE,
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 Multi-function 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.
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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 these
devices are in the SLEEP or IDLE Mode and its system oscillator stopped, situations such as
external edge transitions on the external interrupt pins, 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, MFnF, 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 the 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.
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.
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Configuration Options
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
1
High Speed System Oscillator Selection
fH – HXT or HIRC
2
Low Speed System Oscillator Selection
fSUB – LXT or LIRC
3
HIRC Frequency Selection
fHIRC – 8MHz, 12MHz or 16MHz
Application Circuits
VDD
VDD
SCOMn
0.1µF
SSEG�
VSS
A�0~A�7
See Oscillato�
Section
OSC
Ci�cuit
LCD
Panel
PC0/OSC1
PC1/OSC�
PA0~PA7
PB0~PB6
PC0~PC6
OSC
Ci�cuit
PB0/XT1
PB1/XT�
PD0~PD3
See Oscillato�
Section
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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
Rev. 1.10
192
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
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
Rev. 1.10
193
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
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
Rev. 1.10
194
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
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
Rev. 1.10
195
November 21, 2014
HT66F0175/HT66F0185
A/D 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 and the carry flag are 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
Rev. 1.10
196
November 21, 2014
HT66F0175/HT66F0185
A/D 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
Rev. 1.10
197
November 21, 2014
HT66F0175/HT66F0185
A/D 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
Rev. 1.10
198
November 21, 2014
HT66F0175/HT66F0185
A/D 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
Rev. 1.10
199
November 21, 2014
HT66F0175/HT66F0185
A/D 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 information.
Additional supplementary information with regard to packaging is listed below. Click on the relevant
section to be transferred to the relevant website page.
• Further Package Information (include Outline Dimensions, Product Tape and Reel Specifications)
• Packing Meterials Information
• Carton information
Rev. 1.10
200
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
20-pin SOP (300mil) Outline Dimensions
Symbol
Dimensions in inch
Min.
Nom.
Max.
—
A
—
0.406 BSC
B
—
0.295 BSC
—
C
0.012
—
0.020
C’
—
0.504 BSC
—
D
—
—
0.104
E
—
0.050 BSC
—
F
0.004
—
0.012
G
0.016
—
0.050
H
0.008
—
0.013
α
0°
—
8°
Symbol
Rev. 1.10
Dimensions in mm
Min.
Nom.
Max.
—
A
—
10.30 BSC
B
—
7.5 BSC
—
C
0.31
—
0.51
C’
—
12.8 BSC
—
D
—
—
2.65
E
—
1.27 BSC
—
F
0.10
—
0.30
G
0.40
—
1.27
H
0.20
—
0.33
α
0°
—
8°
201
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
20-pin SSOP (150mil) Outline Dimensions
Symbol
Dimensions in inch
Min.
Nom.
Max.
A
—
0.236 BSC
—
B
—
0.154 BSC
—
C
0.008
—
0.012
C’
—
0.341 BSC
—
D
—
—
0.069
E
—
0.025 BSC
—
F
0.004
—
0.010
G
0.016
—
0.050
H
0.004
—
0.010
α
0°
—
8°
Symbol
Rev. 1.10
Dimensions in mm
Min.
Nom.
Max.
—
A
—
6.0 BSC
B
—
3.9 BSC
—
C
0.20
—
0.30
C’
—
8.66 BSC
—
D
—
—
1.75
E
—
0.635 BSC
—
F
0.10
—
0.25
G
0.41
—
1.27
H
0.10
—
0.25
α
0°
—
8°
202
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
24-pin SOP (300mil) Outline Dimensions
Symbol
Dimensions in inch
Min.
Nom.
Max.
A
—
0.406 BSC
—
B
—
0.295 BSC
—
C
0.012
—
0.020
C’
—
0.606 BSC
—
D
—
—
0.104
E
—
0.050 BSC
—
F
0.004
—
0.012
G
0.016
—
0.050
H
0.008
—
0.013
α
0°
—
8°
Symbol
Rev. 1.10
Dimensions in mm
Min.
Nom.
Max.
—
A
—
10.30 BSC
B
—
7.5 BSC
—
C
0.31
—
0.51
C’
—
15.4 BSC
—
D
—
—
2.65
E
—
1.27 BSC
—
F
0.10
—
0.30
G
0.40
—
1.27
H
0.20
—
0.33
α
0°
—
8°
203
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
24-pin SSOP (150mil) Outline Dimensions
Symbol
Dimensions in inch
Min.
Nom.
Max.
A
—
0.236 BSC
—
B
—
0.154 BSC
—
C
0.008
—
0.012
C’
—
0.341 BSC
—
D
—
—
0.069
E
—
0.025 BSC
—
F
0.004
—
0.010
G
0.016
—
0.050
H
0.004
—
0.010
α
0°
—
8°
Symbol
Rev. 1.10
Dimensions in mm
Min.
Nom.
Max.
—
A
—
6.0 BSC
B
—
3.9 BSC
—
C
0.20
—
0.30
C’
—
8.66 BSC
—
D
—
—
1.75
E
—
0.635 BSC
—
F
0.10
—
0.25
G
0.41
—
1.27
H
0.10
—
0.25
α
0°
—
8°
204
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
28-pin SOP (300mil) Outline Dimensions
Symbol
Dimensions in inch
Min.
Nom.
Max.
A
—
0.406 BSC
—
B
—
0.295 BSC
—
C
0.012
—
0.020
C’
—
0.705 BSC
—
D
—
—
0.104
E
—
0.050 BSC
—
F
0.004
—
0.012
G
0.016
—
0.050
H
0.008
—
0.013
α
0°
—
8°
Symbol
Rev. 1.10
Dimensions in mm
Min.
Nom.
Max.
—
A
—
10.30 BSC
B
—
7.50 BSC
—
C
0.31
—
0.51
C’
—
17.9 BSC
—
D
—
—
2.65
E
—
1.27 BSC
—
F
0.10
—
0.30
G
0.40
—
1.27
H
0.20
—
0.33
α
0°
—
8°
205
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
28-pin SSOP (150mil) Outline Dimensions
Symbol
Dimensions in inch
Min.
Nom.
Max.
A
—
0.236 BSC
—
B
—
0.154 BSC
—
C
0.008
—
0.012
C’
—
0.390 BSC
—
D
—
—
0.069
E
—
0.025 BSC
—
F
0.004
—
0.010
G
0.016
—
0.050
H
0.004
—
0.010
α
0°
—
8°
Symbol
Rev. 1.10
Dimensions in mm
Min.
Nom.
Max.
A
—
6.0 BSC
—
B
—
3.9 BSC
—
C
0.20
—
0.30
C’
—
9.9 BSC
—
D
—
—
1.75
E
—
0.635 BSC
—
F
0.10
—
0.25
G
0.41
—
1.27
H
0.10
—
0.25
α
0°
—
8°
206
November 21, 2014
HT66F0175/HT66F0185
A/D 8-Bit Flash MCU with EEPROM
Copyright© 2014 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.
Rev. 1.10
207
November 21, 2014