HT69F240

Flash 8-Bit MCU with LED/LCD Driver
HT69F240
Revision: V1.10
Date: January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Table of Contents
Features............................................................................................................. 6
CPU Features.......................................................................................................................... 6
Peripheral Features.................................................................................................................. 6
General Description.......................................................................................... 7
Block Diagram................................................................................................... 7
Pin Assignment................................................................................................. 8
Pin Description................................................................................................. 9
Absolute Maximum Ratings........................................................................... 12
D.C. Characteristics........................................................................................ 12
A.C. Characteristics........................................................................................ 14
LVD & LVR Electrical Characteristics........................................................... 15
System Architecture....................................................................................... 16
Clocking and Pipelining.......................................................................................................... 16
Program Counter.................................................................................................................... 17
Stack...................................................................................................................................... 17
Arithmetic and Logic Unit – ALU............................................................................................ 18
Flash Program Memory.................................................................................. 18
Structure................................................................................................................................. 18
Special Vectors...................................................................................................................... 19
Look-up Table......................................................................................................................... 19
Table Program Example......................................................................................................... 19
In Circuit Programming – ICP................................................................................................ 20
On-Chip Debug Support – OCDS.......................................................................................... 21
Data Memory................................................................................................... 21
Structure................................................................................................................................. 22
General Purpose Data Memory............................................................................................. 22
Special Purpose Data Memory.............................................................................................. 22
Special Function Register Description......................................................... 24
Indirect Addressing Registers – IAR0, IAR1.......................................................................... 24
Memory Pointers – MP0, MP1............................................................................................... 24
Bank Pointer – BP.................................................................................................................. 25
Accumulator – ACC................................................................................................................ 25
Program Counter Low Register – PCL................................................................................... 25
Look-up Table Registers – TBLP, TBHP, TBLH...................................................................... 25
Status Register – STATUS..................................................................................................... 26
EEPROM Data Memory................................................................................... 28
EEPROM Registers............................................................................................................... 28
Reading Data from the EEPROM.......................................................................................... 29
Writing Data to the EEPROM................................................................................................. 30
Rev. 1.10
2
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Write Protection...................................................................................................................... 30
EEPROM Interrupt................................................................................................................. 30
Programming Considerations................................................................................................. 31
Oscillator......................................................................................................... 32
Oscillator Overview................................................................................................................ 32
System Clock Configurations................................................................................................. 32
External Crystal/Ceramic Oscillator – HXT............................................................................ 33
Internal RC Oscillator – HIRC................................................................................................ 33
External 32.768kHz Crystal Oscillator – LXT......................................................................... 34
LXT Oscillator Low Power Function....................................................................................... 35
Internal 32kHz Oscillator – LIRC............................................................................................ 35
Supplementary Oscillators..................................................................................................... 35
Operating Modes and System Clocks.......................................................... 36
System Clock......................................................................................................................... 36
System Operation Modes....................................................................................................... 37
Control Register..................................................................................................................... 38
Fast Wake-up......................................................................................................................... 40
Operating Mode Switching..................................................................................................... 41
NORMAL Mode to SLOW Mode Switching............................................................................ 42
SLOW Mode to NORMAL Mode Switching............................................................................ 43
Entering the SLEEP0 Mode................................................................................................... 44
Entering the SLEEP1 Mode................................................................................................... 44
Entering the IDLE0 Mode....................................................................................................... 44
Entering the IDLE1 Mode....................................................................................................... 45
Standby Current Considerations............................................................................................ 45
Wake-up................................................................................................................................. 46
Programming Considerations................................................................................................. 46
Watchdog Timer.............................................................................................. 47
Watchdog Timer Clock Source............................................................................................... 47
Watchdog Timer Control Register.......................................................................................... 47
Watchdog Timer Operation.................................................................................................... 48
Reset and Initialisation................................................................................... 49
Reset Functions..................................................................................................................... 49
Reset Initial Conditions.......................................................................................................... 52
Input/Output Ports.......................................................................................... 55
I/O Port Register List.............................................................................................................. 55
Pull-high Resistors................................................................................................................. 56
Port A Wake-up...................................................................................................................... 56
I/O Port Control Registers...................................................................................................... 56
Pin-shared Functions............................................................................................................. 56
I/O Pin Structures................................................................................................................... 60
I/O Source Current Selection................................................................................................. 60
Programming Considerations................................................................................................. 62
Rev. 1.10
3
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Timer Modules – TM....................................................................................... 63
Introduction............................................................................................................................ 63
TM Operation......................................................................................................................... 63
TM Clock Source.................................................................................................................... 64
TM Interrupts.......................................................................................................................... 64
TM External Pins.................................................................................................................... 64
TM Input/Output Pin Control Registers.................................................................................. 65
Programming Considerations................................................................................................. 66
Compact Type TM – CTM............................................................................... 67
Compact TM Operation.......................................................................................................... 67
Compact Type TM Register Description................................................................................ 68
Compact Type TM Operating Modes..................................................................................... 72
Compare Match Output Mode................................................................................................ 72
Timer/Counter Mode.............................................................................................................. 75
PWM Output Mode................................................................................................................. 75
Periodic Type TM – PTM................................................................................. 78
Periodic TM Operation........................................................................................................... 78
Periodic Type TM Register Description.................................................................................. 79
Periodic Type TM Operating Modes....................................................................................... 83
Compare Output Mode........................................................................................................... 83
Timer/Counter Mode.............................................................................................................. 86
PWM Output Mode................................................................................................................. 86
Single Pulse Output Mode..................................................................................................... 88
Capture Input Mode............................................................................................................... 90
Enhanced Type TM – ETM.............................................................................. 92
Enhanced TM Operation........................................................................................................ 92
Enhanced Type TM Register Description............................................................................... 93
Enhanced Type TM Operating Modes................................................................................. 100
Compare Output Mode......................................................................................................... 100
Timer/Counter Mode............................................................................................................ 105
PWM Output Mode............................................................................................................... 105
Single Pulse Output Mode....................................................................................................111
Capture Input Mode..............................................................................................................113
Software LCD Driver......................................................................................116
LCD Operation......................................................................................................................116
LCD Bias Control..................................................................................................................117
I2C Interface....................................................................................................117
I2C Interface Operation..........................................................................................................117
I2C Registers.........................................................................................................................118
I2C Bus Communication....................................................................................................... 121
UART Interface.............................................................................................. 126
UART External Pins............................................................................................................. 127
UART Data Transfer Scheme.............................................................................................. 127
Rev. 1.10
4
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
UART Status and Control Registers.................................................................................... 127
Baud Generator.................................................................................................................... 132
UART Setup and Control..................................................................................................... 134
UART Transmitter................................................................................................................ 135
UART Receiver.................................................................................................................... 137
Managing Receiver Errors................................................................................................... 138
UART Interrupt Structure..................................................................................................... 139
UART Wake-up.................................................................................................................... 141
Interrupts....................................................................................................... 142
Interrupt Registers................................................................................................................ 142
Interrupt Operation............................................................................................................... 146
External Interrupt.................................................................................................................. 147
Multi-function Interrupt......................................................................................................... 148
Time Base Interrupt.............................................................................................................. 148
I2C Interrupt.......................................................................................................................... 150
UART Interrupt..................................................................................................................... 150
EEPROM Interrupt............................................................................................................... 150
LVD Interrupt........................................................................................................................ 150
TM Interrupts........................................................................................................................ 151
Interrupt Wake-up Function.................................................................................................. 151
Programming Considerations............................................................................................... 152
Low Voltage Detector – LVD........................................................................ 153
LVD Register........................................................................................................................ 153
LVD Operation...................................................................................................................... 154
Configuration Options.................................................................................. 155
Application Circuits...................................................................................... 155
Instruction Set............................................................................................... 156
Introduction.......................................................................................................................... 156
Instruction Timing................................................................................................................. 156
Moving and Transferring Data.............................................................................................. 156
Arithmetic Operations........................................................................................................... 156
Logical and Rotate Operations............................................................................................. 157
Branches and Control Transfer............................................................................................ 157
Bit Operations...................................................................................................................... 157
Table Read Operations........................................................................................................ 157
Other Operations.................................................................................................................. 157
Instruction Set Summary............................................................................. 158
Table conventions................................................................................................................ 158
Instruction Definition.................................................................................... 160
Package Information.................................................................................... 169
24-pin SOP (300mil) Outline Dimensions............................................................................ 170
28-pin SOP (300mil) Outline Dimensions............................................................................ 171
Rev. 1.10
5
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Features
CPU Features
• Operating voltage:
♦♦
fSYS=4MHz: 2.2V~5.5V
♦♦
fSYS=8MHz: 2.2V~5.5V
♦♦
fSYS=12MHz: 2.7V~5.5V
♦♦
fSYS=16MHz: 4.5V~5.5V
• Up to 0.25μs instruction cycle with16MHz system clock at VDD=5V
• Power down and wake-up functions to reduce power consumption
• Oscillator types:
♦♦
External Crystal – HXT
♦♦
External 32.765kHz Crystal – LXT
♦♦
Internal RC – HIRC
♦♦
Internal 32kHz RC – LIRC
• Multi-mode operation: NORMAL, SLOW, IDLE and SLEEP
• Fully integrated internal 4MHz, 8MHz and 12MHz oscillator requires no external components
• All instructions executed in one or two instruction cycles
• Table read instructions
• 63 powerful instructions
• Up to 8-level subroutine nesting
• Bit manipulation instruction
Peripheral Features
• Flash Program Memory: 4K×16
• Data Memory: 256×8
• EEPROM Memory: 64×8
• Watchdog Timer function
• Up to 26 bidirectional I/O lines
• 24 bidirectional I/O lines with LED direct driving capability
• Software LCD driver
• I2C Interface
• Universal Asynchronous Receive Transmit (UART) Interface
• Multiple pin-shared external interrupts
• Multiple Timer Module for time measure, input capture, compare match output, PWM output or
single pulse output function
• Dual Time-Base functions for generation of fixed time interrupt signals
• Low voltage reset function
• Low voltage detect function
• Package types: 24/28-pin SOP
Rev. 1.10
6
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
General Description
The device is a Flash Memory LCD type 8-bit high performance RISC architecture microcontroller,
designed for applications which require an LCD or LED interface. Offering users the convenience of
Flash Memory multi-programming features, the device also includes a wide range of functions and
features. Other memory includes an area of RAM Data Memory together with an area of EEPROM
Data Memory.
Analog features include 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 internal and external oscillator functions are provided including fully integrated low
and high speed system oscillators which requires no external components for their 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 minimise 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 consumer products,
handheld instruments, household appliances, electronically controlled tools and motor driving in
addition to many others.
Block Diagram
Low
Voltage
Detect
Low
Voltage
Reset
Internal
Reset Circuit
8-bit
RISC
MCU
Core
Interrupt
Controller
External
Oscillator
LXT/HXT
Stack
Flash/EEPROM
Programming
Circuitry (ICP/OCDS)
Flash
Program
Memory
Watchdog
Timer
EEPROM
Data
Memory
RAM
Data
Memory
Time
Base
Internal
Oscillator
HIRC/LIRC
Software
LCD Driver
I/O
Rev. 1.10
STM
ETM
PTM
I2C
UART
7
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Pin Assignment
PA2/INT0/ICPCK
PA0/ICPDA
VSS
PA1/LED0/SEG0/XT1
PA3/LED1/SEG1/XT2
VDD
PD1/LED23/SEG23/OSC1
PD0/LED22/SEG22/OSC2
PC7/LED21/SEG21
PC4/LED18/SEG18
PC3/LED17/SEG17
PC2/LED16/SEG16
1
24
2
23
3
22
4
21
5
20
6
19
7
18
8
17
9
16
10
15
11
14
12
13
PA4/LED2/SEG2/CTP/ETCK
PA5/LED3/SEG3/CTCK/ETPA
PA6/LED4/SEG4/TX/ETPIA
PA7/LED5/SEG5/RX
PB0/LED6/SEG6/SDA
PB1/LED7/SEG7/SCL
PB2/LED8/SEG8/INT1/PTPI/ETPB
PB3/LED9/SEG9/PTP/ETPIB
PB4/LED10/SEG10/PTCK
PB7/LED13/SEG13
PC0/LED14/SEG14
PC1/LED15/SEG15
HT69F240
24 SOP-A
PA2/INT0/ICPCK/OCDSCK
PA0/ICPDA/OCDSDA
VSS
PA1/LED0/SEG0/XT1
PA3/LED1/SEG1/XT2
VDD
PD1/LED23/SEG23/OSC1
PD0/LED22/SEG22/OSC2
PC7/LED21/SEG21
PC4/LED18/SEG18
PC3/LED17/SEG17
PC2/LED16/SEG16
1
24
2
23
3
22
4
21
5
20
6
19
7
18
8
17
9
16
10
15
11
14
12
13
PA4/LED2/SEG2/CTP/ETCK
PA5/LED3/SEG3/CTCK/ETPA
PA6/LED4/SEG4/TX/ETPIA
PA7/LED5/SEG5/RX
PB0/LED6/SEG6/SDA
PB1/LED7/SEG7/SCL
PB2/LED8/SEG8/INT1/PTPI/ETPB
PB3/LED9/SEG9/PTP/ETPIB
PB4/LED10/SEG10/PTCK
PB7/LED13/SEG13
PC0/LED14/SEG14
PC1/LED15/SEG15
HT69V240
24 SOP-A
PA2/INT0/ICPCK
PA0/ICPDA
VSS
PA1/LED0/SEG0/XT1
PA3/LED1/SEG1/XT2
VDD
PD1/LED23/SEG23/OSC1
PD0/LED22/SEG22/OSC2
PC7/LED21/SEG21
PC6/LED20/SEG20
PC5/LED19/SEG19
PC4/LED18/SEG18
PC3/LED17/SEG17
PC2/LED16/SEG16
1
28
2
27
3
26
4
25
5
24
6
23
7
22
8
21
9
20
10
19
11
18
12
17
13
16
14
15
PA4/LED2/SEG2/CTP/ETCK
PA5LED3//SEG3/CTCK/ETPA
PA6/LED4/SEG4/TX/ETPIA
PA7/LED5/SEG5/RX
PB0/LED6/SEG6/SDA
PB1/LED7/SEG7/SCL
PB2/LED8/SEG8/INT1/PTPI/ETPB
PB3/LED9/SEG9/PTP/ETPIB
PB4/LED10/SEG10/PTCK
PB5/LED11/SEG11
PB6/LED12/SEG12
PB7/LED13/SEG13
PC0/LED14/SEG14
PC1/LED15/SEG15
HT69F240
28 SOP-A
PA2/INT0/ICPCK/OCDSCK
PA0/ICPDA/OCDSDA
VSS
PA1/LED0/SEG0/XT1
PA3/LED1/SEG1/XT2
VDD
PD1/LED23/SEG23/OSC1
PD0/LED22/SEG22/OSC2
PC7/LED21/SEG21
PC6/LED20/SEG20
PC5/LED19/SEG19
PC4/LED18/SEG18
PC3/LED17/SEG17
PC2/LED16/SEG16
1
28
2
27
3
26
4
25
5
24
6
23
7
22
8
21
9
20
10
19
11
18
12
17
13
16
14
15
PA4/LED2/SEG2/CTP/ETCK
PA5/LED3/SEG3/CTCK/ETPA
PA6/LED4/SEG4/TX/ETPIA
PA7/LED5/SEG5/RX
PB0/LED6/SEG6/SDA
PB1/LED7/SEG7/SCL
PB2/LED8/SEG8/INT1/PTPI/ETPB
PB3/LED9/SEG9/PTP/ETPIB
PB4/LED10/SEG10/PTCK
PB5/LED11/SEG11
PB6/LED12/SEG12
PB7/LED13/SEG13
PC0/LED14/SEG14
PC1/LED15/SEG15
HT69V240
28 SOP-A
Note: 1. If the pin-shared pin functions have multiple outputs simultaneously, the output function is determined by
the corresponding software control bits except the functions determined by the configuration options.
2. The HT69V240 device is the EV chip of the HT69F240 device. It supports the "On-Chip Debug" function
for debugging during development using the OCDSDA and OCDSCK pins connected to the Holtek HTIDE development tools.
Rev. 1.10
8
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Pin Description
Pad Name
PA0/ICPDA/
OCDSDA
PA1/LED0/
SEG0/XT1
PA2/INT0/
ICPCK/
OCDSCK
PA3/LED1/
SEG1/XT2
PA4/LED2/
SEG2/CTP/
ETCK
PA5/LED3/
SEG3/CTCK/
ETPA
PA6/LED4/
SEG4/TX/
ETPIA
Rev. 1.10
Function
OPT
I/T
PA0
PAWU
PAPU
PAFS0
ST
O/T
Description
CMOS General purpose I/O. Register enabled pull-up and wake-up.
ICPDA
—
ST
CMOS ICP Data/Address pin
OCDSDA
—
ST
CMOS OCDS Data/Address pin, for EV chip only.
PA1
PAWU
PAPU
PAFS0
ST
CMOS General purpose I/O. Register enabled pull-up and wake-up.
CMOS LED output
LED0
PAFS0
—
SEG0
PAFS0
—
AO
LCD segment output
XT1
CO
LXT
—
LXT oscillator pin
PA2
PAWU
PAPU
PAFS0
ST
INT0
INTEG
INTC0
ST
CMOS General purpose I/O. Register enabled pull-up and wake-up.
—
External Interrupt 0
ICPCK
—
ST
OCDSCK
—
ST
CMOS ICP Clock pin
PA3
PAWU
PAPU
PAFS0
ST
CMOS General purpose I/O. Register enabled pull-up and wake-up.
CMOS LED output
—
OCDS Clock pin, for EV chip only.
LED1
PAFS0
—
SEG1
PAFS0
—
AO
LCD segment output
XT2
CO
—
LXT
LXT oscillator pin
PA4
PAPU
PAWU
ST
CMOS General purpose I/O. Register enabled pull-up and wake-up.
CMOS LED output
LED2
PAFS1
—
SEG2
PAFS1
—
AO
LCD segment output
CTP
PAFS1
—
ETCK
PAFS1
ST
CMOS CTM output pin
PA5
PAWU
PAPU
PAFS1
ST
CMOS General purpose I/O. Register enabled pull-up and wake-up.
CMOS LED output
—
ETM input pin
LED3
PAFS1
—
SEG3
PAFS1
—
AO
LCD segment output
CTCK
PAFS1
ST
—
CTM input pin
ETPA
PAFS1
—
CMOS ETM output pin
PA6
PAWU
PAPU
PAFS
ST
CMOS General purpose I/O. Register enabled pull-up and wake-up.
CMOS LED output
LED4
PAFS1
—
SEG4
PAFS1
—
TX
PAFS1
—
ETPIA
ETMC1
ST
AO
LCD segment output
CMOS UART transmit pin
—
ETM input pin
9
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Pad Name
PA7/LED5/
SEG5/RX
PB0/LED6/
SEG6/SDA
PB1/LED7/
SEG7/SCL
PB2/LED8/
SEG8/INT1/
PTPI/ETPB
PB3/LED9/
SEG9/PTP/
ETPIB
PB4/LED10/
SEG10/PTCK
PB5/LED11/
SEG11
PB6/LED12/
SEG12
PB7/LED13/
SEG13
PC0/LED14/
SEG14
PC1/LED15/
SEG15
PC2/LED16/
SEG16
Rev. 1.10
Function
OPT
I/T
PA7
PAWU
PAPU
PAFS
O/T
Description
ST
CMOS General purpose I/O. Register enabled pull-up and wake-up.
CMOS LED output
LED5
PAFS1
—
SEG5
PAFS1
—
AO
LCD segment output
RX
PAFS1
ST
—
UART receive pin
PB0
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up
LED6
PBFS0
—
CMOS LED output
SEG6
PBFS0
—
SDA
PBFS0
ST
AO
LCD segment output
NMOS I2C data/address line
PB1
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up
LED7
PBFS0
—
CMOS LED output
SEG7
PBFS0
—
SCL
PBFS0
ST
AO
LCD segment output
NMOS I2C clock line
PB2
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up
LED8
PBFS0
—
CMOS LED output
SEG8
PBFS0
—
AO
LCD segment output
INT1
INTEG
INTC0
ST
—
External Interrupt 1
PTPI
PTMC1
ST
—
PTM input pin
ETPB
PBFS0
—
CMOS ETM output pin
PB3
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up
LED9
PBFS0
—
CMOS LED output
SEG9
PBFS0
—
PTP
PBFS0
—
ETPIB
ETMC1
ST
PB4
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up
CMOS LED output
AO
LCD segment output
CMOS PTM output pin
—
ETM input pin
LED10
PBFS1
—
SEG10
PBFS1
—
AO
LCD segment output
PTCK
PBFS1
ST
—
PTM input pin
PB5
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up
CMOS LED output
LED11
PBFS1
—
SEG11
PBFS1
—
PB6
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up
CMOS LED output
AO
LCD segment output
LED12
PBFS1
—
SEG12
PBFS1
—
PB7
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up
LED13
PBFS1
—
CMOS LED output
SEG13
PBFS1
—
PC0
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up
CMOS LED output
AO
AO
LCD segment output
LCD segment output
LED14
PCFS0
—
SEG14
PCFS0
—
PC1
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up
CMOS LED output
AO
LCD segment output
LED15
PCFS0
—
SEG15
PCFS0
—
PC2
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up
CMOS LED output
LED16
PCFS0
—
SEG16
PCFS0
—
AO
AO
LCD segment output
LCD segment output
10
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Pad Name
PC3/LED17/
SEG17
PC4/LED18/
SEG18
PC5/LED19/
SEG19
PC6/LED20/
SEG20
PC7/LED21/
SEG21
PD0/LED22/
SEG22/OSC2
PD1/LED23/
SEG23/OSC1
Function
OPT
I/T
PC3
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up
O/T
Description
CMOS LED output
LED17
PCFS0
—
SEG17
PCFS0
—
PC4
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up
LED18
PCFS1
—
CMOS LED output
SEG18
PCFS1
—
AO
AO
LCD segment output
LCD segment output
PC5
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up
LED19
PCFS1
—
CMOS LED output
SEG19
PCFS1
—
PC6
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up
CMOS LED output
AO
LCD segment output
LED20
PCFS1
—
SEG20
PCFS1
—
PC7
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up
CMOS LED output
AO
LCD segment output
LED21
PCFS1
—
SEG21
PCFS1
—
PD0
PDPU
ST
CMOS General purpose I/O. Register enabled pull-up
LED22
PDFS0
—
CMOS LED output
SEG22
PDFS0
—
AO
LCD segment output
AO
LCD segment output
HXT
HXT oscillator pin
OSC2
CO
—
PD1
PDPU
ST
CMOS General purpose I/O. Register enabled pull-up
CMOS LED output
LED23
PDFS0
—
SEG23
PDFS0
—
AO
LCD segment output
OSC1
CO
HXT
—
HXT oscillator pin
VDD
VDD
—
PWR
—
Positive Power supply.
VSS
VSS
—
PWR
—
Negative Power supply. Ground.
Legend: I/T: Input type
O/T: Output type
OPT: Optional by configuration option (CO) or register option
PWR: Power
CO: Configuration option
ST: Schmitt Trigger input
AO: Analog output
CMOS: CMOS output
NMOS: NMOS output
HXT: High frequency crystal oscillator
LXT: High frequency crystal oscillator
Rev. 1.10
11
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Absolute Maximum Ratings
Supply Voltage .................................................................................................VSS-0.3V to VSS+6.0V
Input Voltage ...................................................................................................VSS-0.3V to VDD+0.3V
IOL Total ....................................................................................................80mA
Total Power Dissipation ......................................................................................................... 500mW
Storage Temperature .................................................................................................. -50°C to 125°C
Operating Temperature . ............................................................................................... -40°C to 85°C
IOH Total...................................................................................................-80mA
Note: These are stress ratings only. Stresses exceeding the range specified under "Absolute
Maximum Ratings" may cause substantial damage to the device. Functional operation of
this device at other conditions beyond those listed in the specification is not implied and
prolonged exposure to extreme conditions may affect device reliability.
D.C. Characteristics
Ta=25°C
Symbol
VDD
Parameter
Operating Voltage
Test Conditions
VDD
─
3V
5V
3V
5V
IDD1
Operating Current
(fSYS=fH, fSUB=fRTC or fLIRC)
3V
5V
3V
5V
3V
5V
5V
3V
5V
3V
5V
IDD2
Operating Current
(HXT/HIRC, fSYS=fL,
fSUB=fRTC or fLIRC)
3V
5V
3V
5V
3V
5V
3V
5V
IDD3
Rev. 1.10
Operating Current
(LXT/LIRC, fSYS=fL=fRTC,
fSUB=fRTC)
3V
5V
Conditions
Min.
Typ.
Max.
Unit
fSYS=4MHz
2.2
─
5.5
V
fSYS=8MHz
2.2
─
5.5
V
fSYS=12MHz
2.7
─
5.5
V
fSYS=16MHz
4.5
─
5.5
V
─
100
150
μA
─
280
450
μA
─
250
400
uA
─
500
1000
μA
─
420
630
μA
─
700
1500
μA
─
0.8
1.5
mA
No load, fH=455kHz, WDT enable
No load, fH=1MHz, WDT enable
No load, fH=4MHz, WDT enable
No load, fH=8MHz, WDT enable
No load, fH=12MHz, WDT enable
─
1.5
3.0
mA
─
1.5
2.5
mA
─
3.0
5.0
mA
─
4.0
6.0
mA
─
500
750
μA
─
800
1200
μA
─
420
630
μA
─
700
1000
μA
─
400
600
μA
─
600
800
μA
No load, fH=8MHz, fL=fH/16,
WDT enable
─
360
540
μA
─
560
700
μA
No load, fH=8MHz, fL=fH/32,
WDT enable
─
320
480
μA
─
520
650
μA
No load, fH=8MHz, fL=fH/64,
WDT enable
─
280
420
μA
─
440
600
μA
─
10
20
μA
─
30
50
μA
No load, fH=16MHz, WDT enable
No load, fH=8MHz, fL=fH/2, WDT enable
No load, fH=8MHz, fL=fH/4, WDT enable
No load, fH=8MHz, fL=fH/8, WDT enable
No load, WDT enable
12
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Symbol
ISTB1
Parameter
Standby Current (SLEEP0)
(fSYS=off, fSUB=fRTC or fLIRC)
Test Conditions
VDD
3V
5V
Standby Current (SLEEP1)
(fSYS=off, fSUB=fRTC/fLIRC)
3V
ISTB3
Standby Current (IDLE0)
(fSYS=off, fSUB=fLIRC)
3V
ISTB4
Standby Current (IDLE0)
(fSYS=off, fSUB=fRTC)
3V
ISTB5
Standby Current (IDLE1)
(HXT/HIRC, fSYS=fH,
fSUB=fRTC or fLIRC)
3V
ISTB6
Standby Current (IDLE1)
(HXT/HIRC, fSYS=fH,
fSUB=fRTC or fLIRC)
ISTB7
Standby Current (IDLE1)
(HXT/HIRC, fSYS=fH,
fSUB=fRTC or fLIRC)
ISTB2
5V
5V
5V
5V
3V
5V
3V
5V
VIL1
Input Low Voltage
─
VIH1
Input High Voltage
─
VSEGH
Software LCD Segment
Output High
─
VSEGL
Software LCD Segment
Output Low
IOL
I/O Port Sink Current
IOH1
I/O Port Source Current
(PA0 & PA2)
IOH2
ISLCD
RPH
Rev. 1.10
I/O Port Source Current
(Except PA0/PA2)
Software LCD Driver
Operating Current
Pull-high Resistance of I/O
Ports
Conditions
No load, system HALT, WDT disable
No load, system HALT, WDT disable,
LXTLP=1
No load, system HALT, WDT disable
No load, system HALT, WDT disable,
LXTLP=1
No load, system HALT, WDT enable,
fSYS=4MHz, FSYSON=1
No load, system HALT, WDT enable,
fSYS=8MHz, FSYSON=1
No load, system HALT, WDT enable,
fSYS=12MHz, FSYSON=1
Typ.
Max.
Unit
─
0.1
1
μA
─
0.3
2
μA
─
2
3
μA
─
3
5
μA
─
3
5
μA
─
5
10
μA
─
2
4
μA
─
4
8
μA
─
150
200
μA
─
200
400
μA
─
300
400
μA
─
400
600
μA
─
450
600
μA
─
600
900
μA
0V
─
0.3VDD
V
0.7VDD
─
VDD
V
No load
0.645
VDD
0.67
VDD
0.695
VDD
V
─
No load
0.305
VDD
0.33
VDD
0.355
VDD
V
3V
VOL=0.1VDD
6
12
─
mA
5V
VOL=0.1VDD
16
32
─
mA
3V
VOH=0.9VDD
-3
-6
─
mA
5V
VOH=0.9VDD
-8
-16
─
mA
3V
VOH=0.9VDD, PXPSn[m+1:m]=00;
n=0, 1; m=0, 2, 4, 6
-1.0
-2.0
—
mA
5V
VOH=0.9VDD, PXPSn[m+1:m]=00;
n=0, 1; m=0, 2, 4, 6
-2.5
-5.0
—
mA
3V
VOH=0.9VDD, PXPSn[m+1:m]=01;
n=0, 1; m=0, 2, 4, 6
-1.5
-3.0
—
mA
5V
VOH=0.9VDD, PXPSn[m+1:m]=01;
n=0, 1; m=0, 2, 4, 6
-4.0
-8.0
—
mA
3V
VOH=0.9VDD, PXPSn[m+1:m]=10;
n=0, 1; m=0, 2, 4, 6
-2.5
-5.0
—
mA
5V
VOH=0.9VDD, PXPSn[m+1:m]=10;
n=0, 1; m=0, 2, 4, 6
-6.0
-12.0
—
mA
3V
VOH=0.9VDD, PXPSn[m+1:m]=11;
n=0, 1; m=0, 2, 4, 6
-5.0
-10.0
—
mA
5V
VOH=0.9VDD, PXPSn[m+1:m]=11;
n=0, 1; m=0, 2, 4, 6
-13
-26
—
mA
5V
─
Min.
ISEL[1:0]=00
5
8
11
μA
ISEL[1:0]=01
10
16
22
μA
ISEL[1:0]=10
35
50
65
μA
ISEL[1:0]=11
70
100
130
μA
3V
─
20
60
100
kΩ
5V
─
10
30
50
kΩ
13
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
A.C. Characteristics
Ta=25°C
Symbol
fCPU
Parameter
Operating Clock
Test Conditions
VDD
Condition
—
System Clock (HXT)
DC
─
4
MHz
DC
─
8
MHz
2.7V~5.5V
DC
─
12
MHz
4.5V~5.5V
DC
─
16
MHz
0.4
─
8
MHz
2.7V~5.5V
─
3.0V/5.0V Trim@3V/5V, Ta=25°C
System Clock (HIRC)
Max. Unit
2.2V~5.5V
4.5V~5.5V
fHIRC
Typ.
2.2V~5.5V
2.2V~5.5V
fSYS
Min.
0.4
─
12
MHz
0.4
─
16
MHz
-2%
4
+2% MHz
5.0V
Trim@5V, Ta=25°C
-2%
8
+2% MHz
5.0V
Trim@5V, Ta=25°C
-2%
12
+2% MHz
2.2V~5.5V Trim@3V/5V, Ta=-40~85°C
-5%
4
+5% MHz
3.0V~5.5V Trim@5V, Ta=-40~85°C
-5%
8
+5% MHz
4.5V~5.5V Trim@5V, Ta=-40~85°C
-5%
12
+5% MHz
fLXT
System Clock (LXT)
─
fLIRC
System Clock (LIRC)
5.0V
─
─
32768
-10%
32
tTCK
TCK Input Pulse Width
─
tINT
Interrupt Input Pulse Width
─
─
0.3
─
─
μs
─
10
─
─
μs
─
fSYS =HXT or LXT
─
fSYS = HIRC
tSST
System Start-up Timer Period
(Wake-up from HALT, fSYS off
at HALT state, Slow Mode →
Normal Mode, Normal Mode →
Slow Mode)
1024
─
─
tSYS
16
─
─
tSYS
─
fSYS = LIRC
2
─
─
tSYS
Ta = 25°C
─
Hz
+10% kHz
System Start-up Timer Period
(Wake-up from HALT, fSYS on at
HALT State)
─
─
2
─
─
tSYS
System Reset Delay Time
(Power On Reset, LVR Reset,
LVR S/W Reset (LVRC),
WDT S/W Reset (WDTC))
─
─
25
50
100
ms
System Reset Delay Time
(WDT Normal Reset)
─
─
8.3
16.7
33.3
ms
tSRESET
Software Reset Width to Reset
—
—
20
45
90
μs
tEERD
EEPROM Read Time
─
─
1
2
4
tSYS
tEEWR
EEPROM Write Timet
─
─
1
2
4
ms
tRSTD
Note: 1. tSYS= 1/fSYS; tLIRC= 1/fLIRC
Rev. 1.10
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January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
LVD & LVR Electrical Characteristics
Ta=25°C
Symbol
Test Conditions
Parameter
VDD
Low Voltage Reset Voltage
VLVR
—
Low Voltage Detector Voltage
VLVD
—
Min.
Conditions
Typ.
LVR Enable, 2.10V option
2.1
LVR Enable, 2.55V option
2.55
-5%
LVR Enable, 3.15V option
3.15
Max.
Unit
+5%
V
LVR Enable, 3.80V option
3.8
LVDEN=1, VLVD=2.0V
2.0
V
LVDEN=1, VLVD=2.2V
2.2
V
LVDEN=1, VLVD=2.4V
2.4
V
LVDEN=1, VLVD=2.7V
2.7
-5%
LVDEN=1, VLVD=3.0V
3.0
+5%
V
V
LVDEN=1, VLVD=3.3V
3.3
V
LVDEN=1, VLVD=3.6V
3.6
V
LVDEN=1, VLVD=4.0V
4.0
10
V
ILVR
Additional Power Consumption 3.0V
LVR disable → LVR enable
if LVR is used
5.0V
—
20
μA
—
15
30
μA
—
10
20
μA
ILVD
3.0V LVD disable → LVD enable
Additional Power Consumption 5.0V (LVR disable)
if LVD is used
3.0V LVD disable → LVD enable
5.0V (LVR enable)
—
15
30
μA
—
1
2
μA
—
2
4
μA
tLVR
Low Voltage Width to Reset
—
—
120
240
480
μs
tLVD
Low Voltage Width to Interrupt
—
—
20
45
90
μs
tLVDS
LVDO Stable Time
—
For LVR enable, LVD off→on
—
—
15
μs
—
For LVR disable, LVD off→on
—
—
150
μs
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
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HT69F240
Flash 8-Bit MCU with LED/LCD Driver
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 control system with maximum reliability and flexibility. This makes the device
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.
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.


   
   
System Clocking and Pipelining
Rev. 1.10
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January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
  
    
 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 non-consecutive
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.
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.
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 depending upon the device 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.
Rev. 1.10
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January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
If the stack is overflow, the first Program Counter save in the stack will be lost.
P ro g ra m
T o p o f S ta c k
S ta c k L e v e l 1
S ta c k L e v e l 2
S ta c k
P o in te r
B o tto m
C o u n te r
S ta c k L e v e l 3
o f S ta c k
P ro g ra m
M e m o ry
S ta c k L e v e l 8
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
Flash Program Memory
The Program Memory is the location where the user code or program is stored. For this device the
Program Memory is Flash type, which means it can be programmed and re-programmed a large
number of times, allowing the user the convenience of code modification on the same device. By
using the appropriate programming tools, the Flash device offers users the flexibility to conveniently
debug and develop their applications while also offering a means of field programming and updating.
Structure
The Program Memory has a capacity of up to 4k×16 bits. The Program Memory is addressed by the
Program Counter and also contains data, table information and interrupt entries information. Table
data, which can be setup in any location within the Program Memory, is addressed by separate table
pointer registers.
0000H
001CH
0FFFH
Reset
Interrupt
Vector
16 bits
Program Memory Structure
Rev. 1.10
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HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Special Vectors
Within the Program Memory, certain locations are reserved for the reset and interrupts. The location
000H is reserved for use by the device reset for program initialisation. After a device reset is
initiated, the program will jump to this location and begin execution.
Look-up Table
Any location within the Program Memory can be defined as a look-up table where programmers can
store fixed data. To use the look-up table, the table pointer must first be setup by placing the address
of the look up data to be retrieved in the table pointer register, TBLP 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 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 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
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January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Table Read Program Example
tempreg1 db
?; temporary register #1
tempreg2 db
?; temporary register #2
:
:
mov a,06h ; initialise table pointer - note that this address
; is referenced to the last page or present page
mov tblp, a
:
:
tabrdl tempreg1 ; transfers value in table referenced by table pointer
; to tempreg1
; data at program memory address "0F06H" transferred to
; to tempreg1 and TBLH
dec tblp ; reduce value of table pointer by one
tabrdl tempreg2 ; transfers value in table referenced by table pointer
; to tempreg2
; 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
; the value "00H" will be transferred to the high byte
; register TBLH
:
:
org 0F00h; sets initial address of last page
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
in-circuit using a 4-pin interface. This provides manufacturers with the possibility of manufacturing
their circuit boards complete with a programmed or un-programmed microcontroller, and then
programming or upgrading the program at a later stage. This enables product manufacturers to easily
keep their manufactured products supplied with the latest program releases without removal and
re-insertion of the device.
Holtek Writer Pins
MCU Programming Pins
Pin Description
ICPDA
PA0
Programming Serial Data/Address
ICPCK
PA2
Programming Clock
VDD
VDD
Power Supply
VSS
VSS
Ground
The Program 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 and one line for the reset. The technical details
regarding the in-circuit programming of the devices are beyond the scope of this document and will
be supplied in supplementary literature.
Rev. 1.10
20
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
During the programming process, taking control of the ICPDA and ICPCK pins for data and clock
programming purposes. The user must there take care to ensure that no other outputs are connected
to these two pins.
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
W r ite r _ V D D
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 1k or the capacitance of * must be less than 1nF.
On-Chip Debug Support – OCDS
There is an EV chip device, HT69V240, which is used to emulate the real MCU device, HT69F240.
The EV chip device also provides the "On-Chip Debug" function to debug the real MCU device
during development process. The real MCU and EV chip devices are almost functional compatible
except the "On-Chip Debug" function and package types. 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 device. 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".
Holtek e-Link Pins
EV Chip Pins
OCDSDA
OCDSDA
On-Chip Debug Support Data/Address input/output
Pin Description
OCDSCK
OCDSCK
On-Chip Debug Support Clock input
VDD
VDD
Power Supply
GND
VSS
Ground
Data Memory
The Data Memory is an 8-bit wide RAM internal memory and is the location where temporary
information is stored.
Divided into two sections, the first of these is an area of RAM where special function registers are
located. These registers have fixed locations and 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 reserved for
general purpose use. All locations within this area are read and write accessible under program
control. Switching between the different Data Memory banks is achieved by setting the Bank Pointer
to the correct value.
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HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Structure
The Data Memory is subdivided into two banks, all of which are implemented in 8-bit wide RAM.
The Data Memory located in Bank 0 is subdivided into two sections, the Special Purpose Data
Memory and the General Purpose Data Memory. Registers which are located in the Special purpose
data memory and common to all microcontrollers, such as ACC, PCL, etc., have the same Data
Memory address in all banks except the EEC register located at 40H in Bank 1.
Type
Banks
Special Purpose
0: 00H~7FH
1: 40H(EEC)
General Purpose
0: 80H~FFH
1: 80H~FFH
00H
Bank 0
Special Purpose
Data Memory
EEC at 40H in Bank 1
7FH
80H
General Purpose
Data Memory
FFH
Bank 0
Bank 1
Data Memory Structure
General Purpose Data Memory
All microcontroller programs require an area of read/write memory where temporary data can be
stored and retrieved for use later. It is this area of RAM memory that is known as General Purpose
Data Memory. This area of Data Memory is fully accessible by the user programing for both reading
and writing operations. By using the "SET [m].i" and "CLR [m].i" instructions individual bits can be
set or reset under program control giving the user a large range of flexibility for bit manipulation in
the Data Memory.
Special Purpose Data Memory
This area of Data Memory is where registers, necessary for the correct operation of the
microcontroller, are stored. Most of the registers are both readable and writeable but some are
protected and are readable only, the details of which are located under the relevant Special Function
Register section. Note that for locations that are unused, any read instruction to these addresses will
return the value "00H".
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HT69F240
Flash 8-Bit MCU with LED/LCD Driver
00H
01H
02H
03H
04H
05H
06H
07H
08H
09H
0AH
0BH
0CH
0DH
0EH
0FH
10H
11H
12H
13H
14H
15H
16H
17H
18H
19H
1AH
1BH
1CH
1DH
1EH
1FH
20H
21H
22H
23H
24H
25H
26H
27H
28H
29H
2AH
2BH
2CH
2DH
2EH
2FH
30H
31H
32H
33H
34H
35H
36H
37H
38H
39H
Bank 0, 1
IAR0
MP0
IAR1
MP1
BP
ACC
PCL
TBLP
TBLH
TBHP
STATUS
SMOD
LVDC
INTEG
WDTC
TBC
INTC0
INTC1
SMOD1
LVRC
MFI0
MFI1
MFI2
Unused
PAWU
PAPU
PA
PAC
PBPU
PB
PBC
PCPU
PC
PCC
PDPU
PD
PDC
Unused
Unused
Unused
INTC2
RSTC
Unused
Unused
PXPS0
PXPS1
Unused
Unused
Unused
PAFS0
PAFS1
PBFS0
PBFS1
PCFS0
PCFS1
PDFS
Unused
Unused
3AH
3BH
3CH
3DH
3EH
3FH
40H
41H
42H
43H
Bank 0 Bank 1
CTMC0
CTMC1
CTMDL
CTMDH
CTMAL
CTMAH
EEC
EEA
EED
Unused
47H
48H
49H
4AH
4BH
4CH
4DH
4EH
4FH
50H
51H
52H
53H
54H
55H
56H
57H
58H
59H
5AH
5BH
5CH
5DH
5EH
5FH
60H
61H
62H
63H
64H
65H
66H
ETMC0
ETMC1
ETMC2
ETMDL
ETMDH
ETMAL
ETMAH
ETMBL
ETMBH
PTMC0
PTMC1
PTMDL
PTMDH
PTMAL
PTMAH
PTMRPL
PTMRPH
IICC0
IICC1
IICD
IICA
I2CTOC
Unused
Unused
SLCDC
USR
UCR1
UCR2
TXR_RXR
BRG
Unused
7FH
: Unused, read as 00H
Special Purpose Data Memory
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HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Special Function Register Description
Most of the Special Function Register details will be described in the relevant functional section;
however several registers require a separate description in this section.
Indirect Addressing Registers – IAR0, IAR1
The Indirect Addressing Registers, IAR0 and IAR1, although having their locations in normal RAM
register space, do not actually physically exist as normal registers. The method of indirect addressing
for RAM data manipulation uses these Indirect Addressing Registers and Memory Pointers, in
contrast to direct memory addressing, where the actual memory address is specified. Actions on the
IAR0 and IAR1 registers will result in no actual read or write operation to these registers but rather
to the memory location specified by their corresponding Memory Pointers, MP0 or MP1. Acting as a
pair, IAR0 and MP0 can together access data from Bank 0 while the IAR1 and MP1 register pair can
access data from any bank. As the Indirect Addressing Registers are not physically implemented,
reading the Indirect Addressing Registers indirectly will return a result of "00H" and writing to the
registers indirectly will result in no operation.
Memory Pointers – MP0, MP1
Two Memory Pointers, known as MP0 and MP1 are provided. These Memory Pointers are
physically implemented in the Data Memory and can be manipulated in the same way as normal
registers providing a convenient way with which to address and track data. When any operation to
the relevant Indirect Addressing Registers is carried out, the actual address that the microcontroller
is directed to, is the address specified by the related Memory Pointer. MP0, together with Indirect
Addressing Register, IAR0, are used to access data from Bank 0, while MP1 and IAR1 are used to
access data from all banks according to BP register. Direct Addressing can only be used with Bank 0,
all other Banks must be addressed indirectly using MP1 and IAR1.
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
mov
mov
mov
a,04h; setup size of block
block,a
a,offset adres1 ; Accumulator loaded with first RAM address
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.
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HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Bank Pointer – BP
In this device the Data Memory is divided into two banks. Selecting the required Data Memory area
is achieved using the Bank Pointer. The Bank Pointer bit 0 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 banks other than Bank 0 must be implemented using Indirect addressing.
BP Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
—
—
—
DMBP0
R/W
—
—
—
—
—
—
—
R/W
POR
—
—
—
—
—
—
—
0
Bit 7~1
Unimplemented, read as "0"
Bit 0DMBP0: Data memory bank point
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.
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HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Status Register – STATUS
This 8-bit register contains the zero flag (Z), carry flag (C), auxiliary carry flag (AC), overflow flag
(OV), power down flag (PDF), and watchdog time-out flag (TO). These arithmetic/logical operation
and system management flags are used to record the status and operation of the microcontroller.
With the exception of the TO and PDF flags, bits in the status register can be altered by instructions
like most other registers. Any data written into the status register will not change the TO or PDF flag.
In addition, operations related to the status register may give different results due to the different
instruction operations. The TO flag can be affected only by a system power-up, a WDT time-out or
by executing the "CLR WDT" or "HALT" instruction. The PDF flag is affected only by executing
the "HALT" or "CLR WDT" instruction or during a system power-up.
The Z, OV, AC and C flags generally reflect the status of the latest operations.
• C is set if an operation results in a carry during an addition operation or if a borrow does not take
place during a subtraction operation; otherwise C is cleared. C is also affected by a rotate through
carry instruction.
• AC is set if an operation results in a carry out of the low nibbles in addition, or no borrow from
the high nibble into the low nibble in subtraction; otherwise AC is cleared.
• Z is set if the result of an arithmetic or logical operation is zero; otherwise Z is cleared.
• OV is set if an operation results in a carry into the highest-order bit but not a carry out of the
highest-order bit, or vice versa; otherwise OV is cleared.
• PDF is cleared by a system power-up or executing the "CLR WDT" instruction. PDF is set by
executing the "HALT" instruction.
• TO is cleared by a system power-up or executing the "CLR WDT" or "HALT" instruction. TO is
set by a WDT time-out.
In addition, on entering an interrupt sequence or executing a subroutine call, the status register will
not be pushed onto the stack automatically. If the contents of the status registers are important and if
the subroutine can corrupt the status register, precautions must be taken to correctly save it.
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HT69F240
Flash 8-Bit MCU with LED/LCD Driver
STATUS Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
TO
PDF
OV
Z
AC
C
R/W
—
—
R
R
R/W
R/W
R/W
R/W
POR
—
—
0
0
x
x
x
x
"x" unknown
Bit 7, 6
Unimplemented, read as "0"
Bit 5TO: Watchdog Time-Out flag
0: After power up or executing the "CLR WDT" or "HALT" instruction
1: A watchdog time-out occurred
Bit 4PDF: Power down flag
0: After power up or executing the "CLR WDT" instruction
1: By executing the "HALT" instruction
Bit 3OV: Overflow flag
0: No overflow
1: An operation results in a carry into the highest-order bit but not a carry out of the
highest-order bit or vice versa
Bit 2Z: Zero flag
0: The result of an arithmetic or logical operation is not zero
1: The result of an arithmetic or logical operation is zero
Bit 1AC: Auxiliary flag
0: No auxiliary carry
1: An operation results in a carry out of the low nibbles in addition, or no borrow
from the high nibble into the low nibble in subtraction
Bit 0C: Carry flag
0: No carry-out
1: An operation results in a carry during an addition operation or if a borrow does
not take place during a subtraction operation
C is also affected by a rotate through carry instruction.
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HT69F240
Flash 8-Bit MCU with LED/LCD Driver
EEPROM Data Memory
The EEPROM Data Memory capacity is up to 64×8 bits for this device. 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
andWrite 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.
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 Bank1, cannot be addressed
directly and can only be read from or written to indirectly using the MP1 Memory Pointer and
Indirect Addressing Register, IAR1. Because the EEC control register is located at address 40H in
Bank 1, the MP1 Memory Pointer must first be set to the value 40H and the Bank Pointer register,
BP, set to the value, 01H, before any operations on the EEC register are executed.
EEPROM Register List
Bit
Register
Name
7
6
5
4
3
2
1
0
EEA
—
—
EEA5
EEA4
EEA3
EEA2
EEA1
EEA0
EED
EED7
EED6
EED5
EED4
EED3
EED2
EED1
EED0
EEC
—
—
—
—
WREN
WR
RDEN
RD
7
6
5
4
3
2
1
0
EEA Register
Bit
Name
—
—
EEA5
EEA4
EEA3
EEA2
EEA1
EEA0
R/W
—
—
R/W
R/W
R/W
R/W
R/W
R/W
POR
—
—
x
x
x
x
x
x
"x": unknown
Bit 7~6
Unimplemented, read as "0"
Bit 5~0EEA5~EEA0: Data EEPROM address bit 5~bit 0
EED Register
Bit
7
6
5
4
3
2
1
0
Name
EED5
EED4
EED5
EED4
EED3
EED2
EED1
EED0
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 7~0EED7~EED0: Data EEPROM data bit 7~bit 0
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Flash 8-Bit MCU with LED/LCD Driver
EEC Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
WREN
WR
RDEN
RD
R/W
—
—
—
—
R/W
R/W
R/W
R/W
POR
—
—
—
—
0
0
0
0
Bit 7~4
Unimplemented, read as "0"
Bit 3WREN: Data EEPROM write operation enable
0: Disable
1: Enable
This is the Data EEPROM Write Operation Enable bit which must be set high before
Datat EEPROM write operations are carried out. Clearing this bit to zero will inhibit
Data EEPROM write operations.
Bit 2WR: Data 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 bit has not first been set high.
Bit 1RDEN: Data EEPROM read operation enable
0: Disable
1: Enable
This is the Data EEPROM Read Operation Enable bit which must be set high before
Datat EEPROM read operations are carried out. Clearing this bit to zero will inhibit
Data EEPROM read operations.
Bit 0RD: Data 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 bit has not first been set high.
Note: The WREN, WR, RDEN and RD bits can not be set to "1" at the same time in one instruction.
The WR and RD bits can not be set to "1" at the same time.
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 EEAregister. 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.
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HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Writing 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. To write data to the EEPROM, the write enable bit, WREN, in the EEC
register must first be set high to enable the write function. After this, the WR bit in the EEC register
must be immediately set high to initiate a write cycle. These two instructions must be executed
consecutively. The global interrupt bit EMI should also first be cleared before implementing any
write operations, and then set again after the write cycle has started. Note that setting the WR bit
high will not initiate a write cycle if the WREN bit has not been set. As the EEPROM write cycle is
controlled using an internal timer whose operation is asynchronous to microcontroller system clock,
a certain time will elapse before the data will have been written into the EEPROM. Detecting when
the write cycle has finished can be implemented either by polling the WR bit in the EEC register or
by using the EEPROM interrupt. When the write cycle terminates, the WR bit will be automatically
cleared to zero by the microcontroller, informing the user that the data has been written to the
EEPROM. The application program can therefore poll the WR bit to determine when the write cycle
has ended.
Write Protection
Protection against inadvertent write operation is provided in several ways. After the device is
powered-on the Write Enable bit in the control register will be cleared preventing any write
operations. Also at power-on the Bank Pointer, BP, will be reset to zero, which means that Data
Memory Bank 0 will be selected. As the EEPROM control register is located in Bank 1, this adds a
further measure of protection against spurious write operations. During normal program operation,
ensuring that the Write Enable bit in the control register is cleared will safeguard against incorrect
write operations.
EEPROM Interrupt
The EEPROM write interrupt is generated when an EEPROM write cycle has ended. The EEPROM
interrupt must first be enabled by setting the DEE bit in the relevant interrupt register. 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
Multi-function 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. More details can be obtained in the Interrupt section.
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Flash 8-Bit MCU with LED/LCD Driver
Programming Considerations
Care must be taken that data is not inadvertently written to the EEPROM. Protection can be
enhanced by ensuring that the Write Enable bit is normally cleared to zero when not writing. Also
the Bank Pointer could be normally cleared to zero as this would inhibit access to Bank 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.
Programming Examples
Reading Data from the EEPROM – Polling Mothod
MOV A, EEPROM_ADRES
MOV EEA, A
MOV A, 040H MOV MP1, A MOV A, 01H MOV BP, A
SET IAR1.1 SET IAR1.0 BACK:
SZ IAR1.0 JMP BACK
CLR IAR1 CLR BP
MOV A, EED MOV READ_DATA, A
; user defined address
; setup memory pointer MP1
; MP1 points to EEC register
; setup Bank Pointer
; set RDEN bit, enable read operations
; start Read Cycle - set RD bit
; check for read cycle end
; disable EEPROM read/write
; move read data to register
Writing Data to the EEPROM – Polling Mothod
CLR EMI
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
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
; set WREN bit, enable write operations
; Start Write Cycle - set WR bit - executed immediately
; after set WREN bit
; check for write cycle end
; disable EEPROM read/write
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Flash 8-Bit MCU with LED/LCD Driver
Oscillator
Various oscillator options offer the user a wide range of functions according to their various
application requirements. The flexible features of the oscillator functions ensure that the best
optimisation can be achieved in terms of speed and power saving. Oscillator selections and operation
are selected through a combination of configuration options and registers.
Oscillator Overview
In addition to being the source of the main system clock the oscillators also provide clock sources
for the Watchdog Timer and Time Base Interrupts. 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 the 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.
Type
Name
Freq.
External Crystal
HXT
400kHz~16MHz
Internal High Speed RC
HIRC
4, 8 or 12MHz
External Low Speed Crystal
Internal Low Speed RC
LXT
32.768kHz
LIRC
32kHz
Pins
OSC1/OSC2
—
XT1/XT2
—
Oscillator Types
System Clock Configurations
There are four methods of generating the system clock, two high speed oscillators and two low
speed oscillators. The high speed oscillators are is the external crystal/ceramic oscillator and the
internal 4MHz, 8MHz or 12MHz RC oscillator. The two low speed oscillators are the internal 32kHz
RC oscillator and the external 32.768kHz crystal oscillator. Selecting whether the low or high speed
oscillator is used as the system oscillator is implemented using the HLCLK bit and CKS2~CKS0
bits in the SMOD register and as the system clock can be dynamically selected.
HighSpeedOscillation
(HOSC)
HXT
FastWake-upfromSLEEPModeor
IDLEModeControl(forHXTonly)
fH/2
fH/4
fH/8
fH
Prescaler
HIRC
fH/16
fSYS
fH/32
fH/64
HighSpeedOscillation
ConfigurationOption
CKS[2:0],HLCLK
LowSpeedOscillation
(LOSC)
TBCK
LIRC
fSUB
fTB
LXT
TimeBase
fSYS/4
LowSpeedOscillation
ConfigurationOption
Rev. 1.10
fSUB
32
WDT
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HT69F240
Flash 8-Bit MCU with LED/LCD Driver
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. An additional configuration option must be setup
to configure the device according to whether the oscillator frequency is high, defined as equal to or
above 1MHz, or low, which is defined as below 1MHz.
     Crystal/Resonator Oscillator – HXT
Crystal Oscillator C1 and C2 Values
Crystal Frequency
C1
C2
12MHz
0pF
0pF
8MHz
0pF
0pF
4MHz
0pF
0pF
1MHz
100pF
100pF
455kHz (see Note2)
100pF
100pF
Note: 1. C1 and C2 values are for guidance only.
2. XTAL mode configuration option: 455kHz.
Crystal Recommended Capacitor Values
Internal 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 either 4MHz, 8MHz or 12MHz. 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 4MHz, 8MHz or 12MHz
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 PD0 and PD1 are free for use as normal I/O pins.
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Flash 8-Bit MCU with LED/LCD Driver
External 32.768kHz 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 32.768kHz
and requires a 32.768kHz crystal to be connected between pins XT1 and XT2. The external resistor
and capacitor components connected to the 32.768kHz 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's 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
pins.
• If the LXT oscillator is not used for any clock source, the XT1/XT2 pins can be used as
normal I/O pins.
• If the LXT oscillator is used for any clock source, the 32.768kHz crystal should be connected to
the XT1/XT2 pins.
‚    ­ €
  ‚  External LXT Oscillator
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=5M~10MΩ is recommended.
32.768kHz Crystal Recommended Capacitor Values
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Flash 8-Bit MCU with LED/LCD Driver
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 Bit
LXT 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, 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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Flash 8-Bit MCU with LED/LCD Driver
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 Clock
The device has 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 an HXT or HIRC oscillator, selected via a configuration option.
The low speed system clock source can be sourced from the clock, fSUB. If fSUB is selected then it
can be sourced by either the LXT or LIRC oscillators, 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.
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.
HighSpeedOscillation
(HOSC)
HXT
FastWake-upfromSLEEPModeor
IDLEModeControl(forHXTonly)
fH/2
fH/4
fH/8
fH
Prescaler
HIRC
fH/16
fSYS
fH/32
fH/64
HighSpeedOscillation
ConfigurationOption
CKS[2:0],HLCLK
LowSpeedOscillation
(LOSC)
TBCK
LIRC
fSUB
fTB
LXT
TimeBase
fSYS/4
LowSpeedOscillation
ConfigurationOption
fSUB
WDT
System Clock Configurations
Note: When the system clock source fSYS is switched to fSUB from fH, the high speed oscillation will stop to
conserve the power. Thus there is no fH~fH/64 for peripheral circuit to use.
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Flash 8-Bit MCU with LED/LCD Driver
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.
Operating Mode
Description
CPU
fSYS
fSUB
NORMAL Mode
On
fH~fH/64
On
SLOW Mode
On
fSUB
On
IDLE0 Mode
Off
Off
On
IDLE1 Mode
Off
On
On
SLEEP0 Mode
Off
Off
Off
SLEEP1 Mode
Off
Off
On
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 SLEEP Mode is entered when an HALT instruction is executed and when the IDLEN bit in the
SMOD register is low. In the SLEEP0 mode the CPU will be stopped, and the fSUB clock will be
stopped too, and the Watchdog Timer function is disabled. In this mode, the LVDEN is must 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 will
continue to operate if the LVDEN is "1" or the Watchdog Timer function is enabled as its clock
source is from the fSUB.
IDLE0 Mode
The IDLE0 Mode is entered when a HALT instruction is executed and when the IDLEN bit in the
SMOD register is high and the FSYSON bit in the SMOD1 register is low. In the IDLE0 Mode the
system oscillator will be inhibited from driving the CPU but some peripheral functions will remain
operational such as the Watchdog Timer and TMs. In the IDLE0 Mode, the system oscillator will be
stopped while the Watchdog Timer clock, fSUB, will be on.
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Flash 8-Bit MCU with LED/LCD Driver
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 SMOD1 register is high. In the IDLE1 Mode the
system oscillator will be inhibited from driving the CPU but may continue to provide a clock source
to keep some peripheral functions operational such as Time Base and TMs. In the IDLE1 Mode,
the system oscillator will continue to run, and this system oscillator may be high speed or low speed
system oscillator. In the IDLE1 Mode the Watchdog Timer clock, fSUB, will also be on.
Control Register
A register pair, SMOD and SMOD1, is used for overall control of the internal clocks within the
device.
SMOD Register
Bit
7
6
5
4
3
2
1
0
Name
CKS2
CKS1
CKS0
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 7~5 CKS2~CKS0: The system clock selection when HLCLK is "0"
000: fSUB (fLXT or fLIRC)
001: fSUB (fLXT or fLIRC)
010: fH/64
011: fH/32
100: fH/16
101: fH/8
110: fH/4
111: fH/2
These three bits are used to select which clock is used as the system clock source.
In addition to the system clock source the 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 1~2 clock cycles if the LIRC oscillator is used.
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HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Bit 2HTO: High speed system oscillator ready flag
0: Not ready
1: Ready
This is the high speed system oscillator ready flag which indicates when the high speed
system oscillator is stable. This flag is cleared to "0" by hardware when the device is
powered on and then changes to a high level after the high speed system oscillator is
stable. Therefore this flag will always be read as "1" by the application program after
device power-on. The flag will be low when in the SLEEP or IDLE0 Mode but after
a wake-up has occurred, the flag will change to a high level after 1024 clock cycles if
the HXT 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 executed the
device will enter the IDLE Mode. In the IDLE1 Mode the CPU will stop running
but the system clock will continue to keep the peripheral functions operational, if
FSYSON bit is high. If FSYSON bit is low, the CPU and the system clock will all stop
in IDLE0 mode. If the bit is low the device will enter the SLEEP Mode when a HALT
instruction is executed.
bit 0HLCLK: System clock selection
0: fH/2~fH/64 or 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.
SMOD1 Register
Bit
7
6
5
4
3
2
Name
FSYSON
—
R/W
R/W
—
POR
0
—
—
1
0
—
—
RSTF
—
—
R/W
LVRF
LRF
WRF
R/W
R/W
—
0
R/W
x
0
0
"x" unknown
Bit 7 FSYSON: fSYS Control in IDLE Mode
0: Disable
1: Enable
Bit 6~4
Unimplemented, read as "0"
Bit 3RSTF: RSTC Control register software reset flag
0: Not occurred
1: Occurred
This bit is set to 1 if the RSTC register contains any undefined RSTC register values.
This in effect acts like a software-reset function. This bit can only be cleared to 0 by
the application program.
Bit 2LVRF: LVR function reset flag
0: Not occurred
1: Occurred
This bit is set to 1 when a specific Low Voltage Reset situation occurs. This bit can
only be cleared to 0 by the application program.
Bit 1LRF: LVR Control register software reset flag
0: Not occurred
1: Occurred
This bit is set to 1 if the LVRC register contains any non defined LVR voltage register
values. This in effect acts like a software-reset function. This bit can only be cleared to
0 by the application program.
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HT69F240
Flash 8-Bit MCU with LED/LCD Driver
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.
Fast Wake-up
To minimise power consumption the device can enter the SLEEP or IDLE0 Mode, where the system
clock source to the device will be stopped. However when the device is woken up again, it can take
a considerable time for the original system oscillator to restart, stabilize and allow normal operation
to resume. To ensure the device is up and running as fast as possible a Fast Wake-up function is
provided, which allows fSUB, namely the 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 device is woken up from the SLEEP0 mode, the FastWake-up function has no effect
because the fSUB clock is stopped. The FastWake-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 oscillator for the
system to wake-up. The system will then initially run under the fSUB clock source until 1024 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 or LIRC oscillator is used as the system oscillator, then it will take15~16 clock cycles
of the ERC/HIRC oscillator or 1~2 clock cycles of the LIRC osrillator respectively 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
Oscillator
FSTEN
Bit
0
HXT
1
Wake-up Time
(SLEEP0 Mode)
Wake-up Time
(SLEEP1 Mode)
Wake-up Time
(IDLE0 Mode)
Wake-up Time
(IDLE1 Mode)
1024 HXT cycles
1024 HXT cycles
1~2 HXT cycles
1024 HXT cycles
1~2 fSUB cycles
(System runs with fSUB first for 1024 HXT
cycles and then switches over to run with
the HXT clock )
1~2 HXT cycles
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
1024 LXT cycles
1024 LXT cycles
1~2 LXT cycles
Wake-up Times
Note that if the Watchdog Timer is disabled, which means that the fSUB clock drived from the LXT
or LIRC oscillator is off, then there will be no Fast Wake-up function available when the device
wakes-up from the SLEEP0 Mode.
Rev. 1.10
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HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Operating Mode Switching
The device can switch between operating modes dynamically allowing the user to select the best
performance/power ratio for the present task in hand. In this way microcontroller operations that
do not require high performance can be executed using slower clocks thus requiring less operating
current and prolonging battery life in portable applications.
In simple terms, Mode Switching between the NORMAL Mode and SLOW Mode is executed
using the HLCLK bit and CKS2~CKS0 bits in the SMOD register while Mode Switching from the
NORMAL/SLOW Modes to the SLEEP/IDLE Modes is executed via the HALT instruction. When
a HALT instruction is executed, whether the device enters the IDLE Mode or the SLEEP Mode is
determined by the condition of the IDLEN bit in the SMOD register and FSYSON in the SMOD1
register.
When the HLCLK bit switches to a low level, which implies that clock source is switched from the
high speed clock source, fH, to the clock source, fH/2~fH/64 or 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 accompanying flowchart shows what happens when
the device moves between the various operating modes.
­ €    
­ €    Rev. 1.10
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HT69F240
Flash 8-Bit MCU with LED/LCD Driver
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 the LIRC oscillators and therefore requires these
oscillators to be stable before full mode switching occurs. This is monitored using the LTO bit in the
SMOD register.
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42
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
  
     ­          ­   € ‚      ­   € ‚      ­   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 NORMAL Mode, where the high speed system oscillator is used, the HLCLK bit should
be set to "1" or HLCLK bit is "0", but CKS2~CKS0 is set to "010", "011", "100", "101", "110" or
"111". As a certain amount of time will be required for the high frequency clock to stabilise, the
status of the HTO bit is checked. The amount of time required for high speed system oscillator
stabilization depends upon which high speed system oscillator type is used.
Rev. 1.10
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HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Entering the SLEEP0 Mode
There is only one way for the device to enter the SLEEP0 Mode and that is to execute the "HALT"
instruction in the application program with the IDLEN bit in SMOD register equal to "0" and the
WDT and LVD both off. When this instruction is executed under the conditions described above, the
following will occur:
• The system clock and the fSUB 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 as the WDT is disabled.
• The I/O ports will maintain their present conditions.
• In the status register, the Power Down flag, PDF, will be set and the Watchdog time-out flag, TO,
will be cleared.
Entering the SLEEP1 Mode
There is only one way for the device to enter the SLEEP1 Mode and that is to execute the "HALT"
instruction in the application program with the IDLEN bit in SMOD register equal to "0" and the
WDT or LVD on. 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 WDT or LVD will remain active 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 as the WDT is enabled and its clock source is
selected to come from the fSUB clock.
• The I/O ports will maintain their present conditions.
• In the status register, the Power Down flag, PDF, will be set and the Watchdog time-out flag, TO,
will be cleared.
Entering the IDLE0 Mode
There is only one way for the device to enter the IDLE0 Mode and that is to execute the "HALT"
instruction in the application program with the IDLEN bit in SMOD register equal to "1" and the
FSYSON bit in SMOD1 register equal to "0". When this instruction is executed under the conditions
described above, the following will occur:
• The system clock will be stopped and the application program will stop at the "HALT"
instruction, but the fSUB clock will be on.
• The Data Memory contents and registers will maintain their present condition.
• The WDT will be cleared and resume counting as the WDT clock source is derived from the fSUB
clock.
• The I/O ports will maintain their present conditions.
• In the status register, the Power Down flag, PDF, will be set and the Watchdog time-out flag, TO,
will be cleared.
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Flash 8-Bit MCU with LED/LCD Driver
Entering the IDLE1 Mode
There is only one way for the device to enter the IDLE1 Mode and that is to execute the "HALT"
instruction in the application program with the IDLEN bit in SMOD register equal to "1" and the
FSYSON bit in SMOD1 register equal to "1". When this instruction is executed under the conditions
described above, the following will occur:
• The system clock and fSUB clock will be on and the application program will stop at the "HALT"
instruction.
• The Data Memory contents and registers will maintain their present condition.
• The WDT will be cleared and resume counting as the WDT clock source is derived from the fSUB
clock.
• The I/O ports will maintain their present conditions.
• In the status register, the Power Down flag, PDF, will be set and the Watchdog time-out flag, TO,
will be cleared.
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 configuration options have enabled the LXT or LIRC
oscillator.
In the IDLE1 Mode the system oscillator is on, if the system oscillator is from the high speed system
oscillator, the additional standby current will also be perhaps in the order of several hundred micro-amps.
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Flash 8-Bit MCU with LED/LCD Driver
Wake-up
After the system enters the SLEEP or IDLE Mode, it can be woken up from one of various sources
listed as follows:
• An external reset
• An external falling edge on Port A
• A system interrupt
• A WDT overflow
If the device is woken up by a WDT overflow, a Watchdog Timer reset will be initiated. The PDF
flag is cleared by a system power-up or executing the clear Watchdog Timer instructions and is set
when executing the "HALT" instruction. The TO flag is set if a WDT time-out occurs, and causes
a wake-up that only resets the Program Counter and Stack Pointer, the other flags remain in their
original status.
Each pin on Port A can be setup using the PAWU register to permit a negative transition on the pin
to wake-up the system. When a Port A pin wake-up occurs, the program will resume execution at
the instruction following the "HALT" instruction. If the system is woken up by an interrupt, then
two possible situations may occur. The first is where the related interrupt is disabled or the interrupt
is enabled but the stack is full, in which case the program will resume execution at the instruction
following the "HALT" instruction. In this situation, the interrupt which woke-up the device will not
be immediately serviced, but will rather be serviced later when the related interrupt is finally enabled
or when a stack level becomes free. The other situation is where the related interrupt is enabled and
the stack is not full, in which case the regular interrupt response takes place. If an interrupt request
flag is set high before entering the SLEEP or IDLE Mode, the wake-up function of the related
interrupt will be disabled.
Programming Considerations
The HXT and LXT oscillators both use the same SST counter. For example, if the system is woken
up from the SLEEP0 Mode and both the HXT and LXT oscillators need to start-up from an off state.
The LXT oscillator uses the SST counter after HXT oscillator has finished its SST period.
• If the device is woken up from the SLEEP0 Mode to the NORMAL Mode, the high speed system
oscillator needs an SST period. The device will execute first instruction after HTO is "1". At
this time, the LXT oscillator may not be stable 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 device is woken up from the SLEEP1 Mode to NORMAL Mode, and the system clock
source is from HXT oscillator and FSTEN is "1", the system clock can be switched to the LXT or
LIRC oscillator after wake up.
• There are peripheral functions, such as Time Base 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 fSUB on/off condition depends upon whether the WDT or LVD is enabled or both disabled as
the clock source is selected from fSUB.
Rev. 1.10
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Flash 8-Bit MCU with LED/LCD Driver
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 which is supplied by the
fSUB clock. The fSUB clock can be sourced from either the LXT or LIRC oscillator selected by a
configuration option. The LIRC internal oscillator has an approximate frequency of 32kHz and this
specified internal clock period can vary with VDD, temperature and process variations. The LXT
oscillator is supplied by an external 32.768kHz crystal. 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 time-out period as well as the enable/disable
operation. This register controls the overall operation of the Watchdog Timer.
WDTC Register
Bit
7
6
5
4
3
2
1
0
Name
WE4
WE3
WE2
WE1
WE0
WS2
WS1
WS0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
1
0
1
0
0
1
1
Bit 7~3 WE4~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 fSUB clock cycles and the
WRF bit in the SMOD1 register will be set to 1.
Bit 2~0WS2~WS0: Select WDT Timeout Period
000: 28/fS
001: 210/fS
010: 212/fS
011: 214/fS
100: 215/fS
101: 216/fS
110: 217/fS
111: 218/fS
These three bits determine the division ratio of the Watchdog Timer source clock,
which in turn determines the timeout period.
Rev. 1.10
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Flash 8-Bit MCU with LED/LCD Driver
SMOD1 Register
Bit
7
6
5
4
3
2
Name
FSYSON
—
R/W
R/W
—
POR
0
—
—
1
0
—
—
RSTF
—
—
R/W
LVRF
LRF
WRF
R/W
R/W
—
0
R/W
x
0
0
"x" unknown
Bit 7 FSYSON: fSYS Control in IDLE Mode
Described elsewhere.
Bit 6~4
Unimplemented, read as "0"
Bit 3RSTF: RSTC Control register software reset flag
Described elsewhere.
Bit 2LVRF: LVR function reset flag
Described elsewhere.
Bit 1LRF: LVR Control register software reset flag
Described elsewhere.
bit 0WRF: WDT Control register software reset flag
0: Not 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.
Watchdog Timer Operation
The Watchdog Timer operates by providing a device reset when its timer overflows. This means
that in the application program and during normal operation the user has to strategically clear the
Watchdog Timer before it overflows to prevent the Watchdog Timer from executing a reset. This is
done using the clear watchdog instructions. If the program malfunctions for whatever reason, jumps
to an unknown location, or enters an endless loop, 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 additional 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, other than 01010B and 10101B, it will reset the device after 2~3 fSUB 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.
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Flash 8-Bit MCU with LED/LCD Driver
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 Register
Reset MCU
WE4~WE0 bits
CLR
“HALT”Instruction
“CLR WDT”Instruction
M
U
X
LXT
LIRC
fSUB
Low Speed Oscillator
Configuration option
8-stage Divider
fSUB/28
WDT Prescaler
WS2~WS0
(fSUB/28 ~ fSUB/218)
8-to-1 MUX
WDT Time-out
(28/fSUB ~ 218/fSUB)
Watchdog Timer
Reset and Initialisation
A reset function is a fundamental part of any microcontroller ensuring that the device can be set
to some predetermined condition irrespective of outside parameters. The most important reset
condition is after power is first applied to the microcontroller. In this case, internal circuitry will
ensure that the microcontroller, after a short delay, will be in a well defined state and ready to
execute the first program instruction. After this power-on reset, certain important internal registers
will be set to defined states before the program commences. One of these registers is the Program
Counter, which will be reset to zero forcing the microcontroller to begin program execution from the
lowest Program Memory address.
Another type of reset is when the Watchdog Timer overflows and resets the MCU. All types of reset
operations result in different register conditions being setup. Another reset exists in the form of a
Low Voltage Reset, LVR, where a full reset, is implemented in situations where the power supply
voltage falls below a certain threshold.
Reset Functions
There are four ways in which a reset can occur.
Power-on Reset
The most fundamental and unavoidable reset is the one that occurs after power is first applied to the.
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.
Power-On Reset Timing Chart
Note: tRSTD is power-on delay, typical time=50ms
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Flash 8-Bit MCU with LED/LCD Driver
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 SMOD1 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 A.C. 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 fSUB clock cycles.
When this happens, the LRF bit in the SMOD1 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.
Note: tRSTD is power-on delay, typical time=50ms
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
Any other values: Generates 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 values above, an MCU reset will be generated. The reset operation will
be activated after 2~3 fSUB 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 fSUB clock
cycles. However in this situation the register contents will be reset to the POR value.
Rev. 1.10
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Flash 8-Bit MCU with LED/LCD Driver
• SMOD1 Register
Bit
7
6
5
4
3
2
Name
FSYSON
—
R/W
R/W
—
POR
0
—
—
1
0
—
—
RSTF
—
—
R/W
LVRF
LRF
WRF
R/W
R/W
—
0
R/W
x
0
0
"x" unknown
Bit 7 FSYSON: fSYS Control in IDLE Mode
Described elsewhere.
Bit 6~4
Unimplemented, read as "0"
Bit 3RSTF: RSTC Control register software reset flag
Described elsewhere.
Bit 2LVRF: LVR function reset flag
0: Not occurred
1: Occurred
This bit is set to 1 when a specific Low Voltage Reset situation condition occurs. 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 if the LVRC register contains any non defined LVR voltage register
values. This in effect acts like a software-reset function. This bit can only be cleared to
0 by the application program.
bit 0WRF: WDT Control register software reset flag
Described elsewhere.
Watchdog Time-out Reset during Normal Operation
The Watchdog time-out Reset during normal operation is the same as a hardware RES pin reset
except that the Watchdog time-out flag TO will be set to "1".
WDT Time-out Reset during Normal Operation Timing Chart
Note: tRSTD is power-on delay, typical time=16.7ms
Watchdog Time-out Reset during SLEEP or IDLE Mode
The Watchdog time-out Reset during SLEEP or IDLE Mode is a little different from other kinds
of reset. Most of the conditions remain unchanged except that the Program Counter and the Stack
Pointer will be cleared to "0" and the TO flag will be set to "1". Refer to the A.C. Characteristics for
tSST details.
WDT Time-out Reset during SLEEP or IDLE Timing Chart
Note: The tSST is 15~16 clock cycles if the system clock source is provided by ERC or
HIRC. The tSST is 1024 clock for HXT or LXT. The tSST is 1~2 clock for LIRC.
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Flash 8-Bit MCU with LED/LCD Driver
Reset Initial Conditions
The different types of reset described affect the reset flags in different ways. These flags, known
as PDF and TO are located in the status register and are controlled by various microcontroller
operations, such as the SLEEP or IDLE Mode function or Watchdog Timer. The reset flags are
shown in the table:
TO
PDF
0
0
Power-on reset
RESET Conditions
u
u
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
Condition After RESET
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.
Power-on Reset
LVR Reset
WDT Time-out
(Normal Operation)
WDT Time-out
(HALT)
IAR0
xxxx xxxx
uuuu uuuu
uuuu uuuu
uuuu uuuu
MP0
xxxx xxxx
uuuu uuuu
uuuu uuuu
uuuu uuuu
IAR1
xxxx xxxx
uuuu uuuu
uuuu uuuu
uuuu uuuu
MP1
xxxx xxxx
uuuu uuuu
uuuu uuuu
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
TBLP
xxxx xxxx
uuuu uuuu
uuuu uuuu
uuuu uuuu
TBLH
xxxx xxxx
uuuu uuuu
uuuu uuuu
uuuu uuuu
TBHP
---- xxxx
---- uuuu
---- uuuu
---- uuuu
Register
Rev. 1.10
STATUS
--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
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
INTC0
-000 0000
-000 0000
-000 0000
-uuu uuuu
INTC1
0000 0000
0000 0000
0000 0000
uuuu uuuu
SMOD1
0--- xx00
0--- xx00
0--- uuuu
u--- uuuu
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HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Register
LVRC
Rev. 1.10
Power-on Reset
LVR Reset
WDT Time-out
(Normal Operation)
WDT Time-out
(HALT)
0101 0101
uuuu uuuu
0101 0101
uuuu uuuu
MFI0
0000 0000
0000 0000
0000 0000
uuuu uuuu
MFI1
-000 -000
-000 -000
-000 -000
-uuu -uuu
MFI2
--00 --00
--00 --00
--00 --00
--uu --uu
INTC2
--00 --00
--00 --00
--00 --00
--uu --uu
PAWU
0000 0000
0000 0000
0000 0000
uuuu uuuu
PAPU
0000 0000
0000 0000
0000 0000
uuuu uuuu
PA
1111 1111
1111 1111
1111 1111
uuuu uuuu
PAC
1111 1111
1111 1111
1111 1111
uuuu uuuu
PBPU
0000 0000
0000 0000
0000 0000
uuuu uuuu
PB
1111 1111
1111 1111
1111 1111
uuuu uuuu
PBC
1111 1111
1111 1111
1111 1111
uuuu uuuu
PCPU
0000 0000
0000 0000
0000 0000
uuuu uuuu
PC
1111 1111
1111 1111
1111 1111
uuuu uuuu
PCC
1111 1111
1111 1111
1111 1111
uuuu uuuu
PDPU
---- --00
---- --00
---- --00
---- --uu
PD
---- --11
---- --11
---- --11
---- --uu
PDC
---- --11
---- --11
---- --11
---- --uu
RSTC
0101 0101
0101 0101
0101 0101
uuuu uuuu
PXFS0
0000 0000
0000 0000
0000 0000
uuuu uuuu
PXFS1
--00 0000
--00 0000
--00 0000
--uu uuuu
PAFS0
0000 0000
0000 0000
0000 0000
uuuu uuuu
PAFS1
0000 0000
0000 0000
0000 0000
uuuu uuuu
PBFS0
0000 0000
0000 0000
0000 0000
uuuu uuuu
PBFS1
0000 0000
0000 0000
0000 0000
uuuu uuuu
PCFS0
0000 0000
0000 0000
0000 0000
uuuu uuuu
PCFS1
0000 0000
0000 0000
0000 0000
uuuu uuuu
PDFS0
---- 0000
---- 0000
---- 0000
---- uuuu
CTMC0
0000 0000
0000 0000
0000 0000
uuuu uuuu
CTMC1
0000 0000
0000 0000
0000 0000
uuuu uuuu
CTMDL
0000 0000
0000 0000
0000 0000
uuuu uuuu
CTMDH
---- --00
---- --00
---- --00
---- --uu
CTMAL
0000 0000
0000 0000
0000 0000
uuuu uuuu
CTMAH
---- --00
---- --00
---- --00
---- --uu
EEA
--00 0000
--00 0000
--00 0000
--uu uuuu
EED
0000 0000
0000 0000
0000 0000
uuuu uuuu
EEC
---- 0000
---- 0000
---- 0000
---- uuuu
ETMC0
0000 0000
0000 0000
0000 0000
uuuu uuuu
ETMC1
0000 0000
0000 0000
0000 0000
uuuu uuuu
ETMC2
0000 0000
0000 0000
0000 0000
uuuu uuuu
ETMDL
0000 0000
0000 0000
0000 0000
uuuu uuuu
ETMDH
---- --00
---- --00
---- --00
---- --uu
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HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Register
ETMAL
Power-on Reset
LVR Reset
WDT Time-out
(Normal Operation)
WDT Time-out
(HALT)
0000 0000
0000 0000
0000 0000
uuuu uuuu
ETMAH
---- --00
---- --00
---- --00
---- --uu
ETMBL
0000 0000
0000 0000
0000 0000
uuuu uuuu
ETMBH
---- --00
---- --00
---- --00
---- --uu
PTMC0
0000 0---
0000 0---
0000 0---
uuuu u---
PTMC1
0000 0000
0000 0000
0000 0000
uuuu uuuu
PTMDL
0000 0000
0000 0000
0000 0000
uuuu uuuu
PTMDL
0000 0000
0000 0000
0000 0000
uuuu uuuu
PTMDH
---- --00
---- --00
---- --00
---- --uu
PTMAL
0000 0000
0000 0000
0000 0000
uuuu uuuu
PTMAH
---- --00
---- --00
---- --00
---- --uu
PTMRPL
0000 0000
0000 0000
0000 0000
uuuu uuuu
PTMRPH
---- --00
---- --00
---- --00
---- --uu
IICC0
---- 000-
---- 000-
---- 000-
---- uuu-
IICC1
1000 0001
1000 0001
1000 0001
uuuu uuuu
IICD
xxxx xxxx
xxxx xxxx
xxxx xxxx
xxxx xxxx
IICA
0000 000-
0000 000-
0000 000-
uuuu uuu-
I2CTOC
0000 0000
0000 0000
0000 0000
uuuu uuuu
SLCDC
-000 ----
-000 ----
-000 ----
-uuu ----
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
xxxx xxxx
xxxx xxxx
xxxx xxxx
uuuu uuuu
Note: "-" not implement
"u" means "unchanged"
"x" means "unknown"
Rev. 1.10
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Flash 8-Bit MCU with LED/LCD Driver
Input/Output Ports
Holtek microcontrollers offer considerable flexibility on their I/O ports. With the input or output
designation of every pin fully under user program control, pull-high selections for all ports and
wake-up selections on certain pins, the user is provided with an I/O structure to meet the needs of a
wide range of application possibilities.
The device provides 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.
I/O Port Register List
Bit
Register
Name
7
6
5
4
3
2
1
0
PAWU
PAWU7
PAWU 6
PAWU5
PAWU4
PAWU3
PAWU2
PAWU1
PAWU0
PAPU
PAPU7
PAPU6
PAPU5
PAPU4
PAPU3
PAPU2
PAPU1
PAPU0
PA
PA7
PA6
PA5
PA4
PA3
PA2
PA1
PA0
PAC
PAC7
PAC6
PAC5
PAC4
PAC3
PAC2
PAC1
PAC0
PBPU
PBPU7
PBPU6
PBPU5
PBPU4
PBPU3
PBPU2
PBPU1
PBPU0
PB
PB7
PB6
PB5
PB4
PB3
PB2
PB1
PB0
PBC
PBC7
PBC6
PBC5
PBC4
PBC3
PBC2
PBC1
PBC0
PCPU
PCPU7
PCPU6
PCPU5
PCPU4
PCPU3
PCPU2
PCPU1
PCPU0
PC
PC7
PC6
PC5
PC4
PC3
PC2
PC1
PC0
PCC
PCC7
PCC6
PCC4
PCC4
PCC3
PCC2
PCC1
PCC0
PDPU
—
—
—
—
—
—
PDPU1
PDPU0
PD
—
—
—
—
—
—
PD1
PD0
PDC
—
—
—
—
—
—
PDC1
PDC0
"—" Unimplemented, read as "0"
PAWUn: PA wake-up function control
0: Disable
1: Enable
PAn/PBn/PCn/PDn: I/O Data bit
0: Data 0
1: Data 1
PACn/PBCn/PCCn/PDCn: I/O type selection
0: Output
1: Input
PAPUn/PBPUn/PCPUn/PDPUn: Pull-high function control
0: Disable
1: Enable
Rev. 1.10
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HT69F240
Flash 8-Bit MCU with LED/LCD Driver
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 registers PAPU~PDPU, 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.
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.
Pin-shared Functions
The flexibility of the microcontroller range is greatly enhanced by the use of pins that have more
than one function. Limited numbers of pins can force serious design constraints on designers but by
supplying pins with multi-functions, many of these difficulties can be overcome. For these pins, the
chosen function of the multi-function I/O pins is selected by a series of regiters via the application
program control.
Bit
Register
Name
7
6
5
4
3
2
1
0
PAFS0
PAFS07
PAFS06
PAFS05
PAFS04
PAFS03
PAFS02
PAFS01
PAFS00
PAFS1
PAFS17
PAFS16
PAFS15
PAFS14
PAFS13
PAFS12
PAFS11
PAFS10
PBFS0
PBFS07
PBFS06
PBFS05
PBFS04
PBFS03
PBFS02
PBFS01
PBFS00
PBFS1
PBFS17
PBFS16
PBFS15
PBFS14
PBFS13
PBFS12
PBFS11
PBFS10
PCFS0
PCFS07
PCFS06
PCFS05
PCFS04
PCFS03
PCFS02
PCFS01
PCFS00
PCFS1
PCFS17
PCFS16
PCFS15
PCFS14
PCFS13
PCFS12
PCFS11
PCFS10
PDFS0
—
—
—
—
PDFS03
PDFS02
PDFS01
PDFS00
Pin-shared Function Selection Register List
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Flash 8-Bit MCU with LED/LCD Driver
PAFS0 Register
Bit
7
6
5
4
3
2
1
0
Name
PAFS07
PAFS06
PAFS05
PAFS04
PAFS03
PAFS02
PAFS01
PAFS00
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
"x": don’t care
Bit 7~6PAFS07~PAFS06: Port A 3 Function Selection
00: PA3/LED1
01: PA3/LED1
10: SEG_L (1/3*VDD)
11: SEG_H (2/3*VDD)
Bit 5~4PAFS05~PAFS04: Port A 2 Function Selection
xx: PA2
Bit 3~2PAFS03~PAFS02: Port A 1 Function Selection
00: PA1/LED0
01: PA1/LED0
10: SEG_L (1/3*VDD)
11: SEG_H (2/3*VDD)
Bit 1~0PAFS01~PAFS00: Port A 0 Function Selection
xx: PA0
PAFS1 Register
Bit
7
6
5
4
3
2
1
0
Name
PAFS17
PAFS16
PAFS15
PAFS14
PAFS13
PAFS12
PAFS11
PAFS10
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 7~6PAFS17~PAFS16: Port A 7 Function Selection
00: PA7/LED5
01: RX
10: SEG_L (1/3*VDD)
11: SEG_H (2/3*VDD)
Bit 5~4PAFS15~PAFS14: Port A 6 Function Selection
00: PA6/LED4
01: TX
10: SEG_L (1/3*VDD)
11: SEG_H (2/3*VDD)
Bit 3~2PAFS13~PAFS12: Port A 5 Function Selection
00: PA5/LED3
01: ETPA
10: SEG_L (1/3*VDD)
11: SEG_H (2/3*VDD)
Bit 1~0PAFS11~PAFS10: Port A 4 Function Selection
00: PA4/LED2
01: CTP
10: SEG_L (1/3*VDD)
11: SEG_H (2/3*VDD)
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Flash 8-Bit MCU with LED/LCD Driver
PBFS0 Register
Bit
7
6
5
4
3
2
1
0
Name
PBFS07
PBFS06
PBFS05
PBFS04
PBFS03
PBFS02
PBFS01
PBFS00
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 7~6PBFS07~PBFS06: Port B 3 Function Selection
00: PB3/LED9
01: PTP
10: SEG_L (1/3*VDD)
11: SEG_H (2/3*VDD)
Bit 5~4PBFS05~PBFS04: Port B 2 Function Selection
00: PB2/LED8
01: ETPB
10: SEG_L (1/3*VDD)
11: SEG_H (2/3*VDD)
Bit 3~2PBFS03~PBFS02: Port B 1 Function Selection
00: PB1/LED7
01: SCL
10: SEG_L (1/3*VDD)
11: SEG_H (2/3*VDD)
Bit 1~0PBFS01~PBFS00: Port B 0 Function Selection
00: PB0/LED6
01: SDA
10: SEG_L (1/3*VDD)
11: SEG_H (2/3*VDD)
PBFS1 Register
Bit
7
6
5
4
3
2
1
0
Name
PBFS17
PBFS16
PBFS15
PBFS14
PBFS13
PBFS12
PBFS11
PBFS10
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 7~6PBFS17~PBFS16: Port B 7 Function Selection
00: PB7/LED13
01: PB7/LED13
10: SEG_L (1/3*VDD)
11: SEG_H (2/3*VDD)
Bit 5~4PBFS15~PBFS14: Port B 6 Function Selection
00: PB6/LED12
01: PB6/LED12
10: SEG_L (1/3*VDD)
11: SEG_H (2/3*VDD)
Bit 3~2PBFS13~PBFS12: Port B 5 Function Selection
00: PB5/LED11
01: PB5/LED11
10: SEG_L (1/3*VDD)
11: SEG_H (2/3*VDD)
Bit 1~0PBFS11~PBFS10: Port B 4 Function Selection
00: PB4/LED10
01: PB4/LED10
10: SEG_L (1/3*VDD)
11: SEG_H (2/3*VDD)
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Flash 8-Bit MCU with LED/LCD Driver
PCFS0 Register
Bit
7
6
5
4
3
2
1
0
Name
PCFS07
PCFS06
PCFS05
PCFS04
PCFS03
PCFS02
PCFS01
PCFS00
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 7~6PCFS07~PCFS06: Port C 3 Function Selection
00: PC3/LED17
01: PC3/LED17
10: SEG_L (1/3*VDD)
11: SEG_H (2/3*VDD)
Bit 5~4PCFS05~PCFS04: Port C 2 Function Selection
00: PC2/LED16
01: PC2/LED16
10: SEG_L (1/3*VDD)
11: SEG_H (2/3*VDD)
Bit 3~2PCFS03~PCFS02: Port C 1 Function Selection
00: PC1/LED15
01: PC1/LED15
10: SEG_L (1/3*VDD)
11: SEG_H (2/3*VDD)
Bit 1~0PCFS01~PCFS00: Port C 0 Function Selection
00: PC0/LED14
01: PC0/LED14
10: SEG_L (1/3*VDD)
11: SEG_H (2/3*VDD)
PCFS1 Register
Bit
7
6
5
4
3
2
1
0
Name
PCFS17
PCFS16
PCFS15
PCFS14
PCFS13
PCFS12
PCFS11
PCFS10
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 7~6PCFS17~PCFS16: Port C 7 Function Selection
00: PC7/LED21
01: PC7/LED21
10: SEG_L (1/3*VDD)
11: SEG_H (2/3*VDD)
Bit 5~4PCFS15~PCFS14: Port C 6 Function Selection
00: PC6/LED20
01: PC6/LED20
10: SEG_L (1/3*VDD)
11: SEG_H (2/3*VDD)
Bit 3~2PCFS13~PCFS12: Port C 5 Function Selection
00: PC5/LED19
01: PC5/LED19
10: SEG_L (1/3*VDD)
11: SEG_H (2/3*VDD)
Bit 1~0PCFS11~PCFS10: Port C 4 Function Selection
00: PC4/LED18
01: PC4/LED18
10: SEG_L (1/3*VDD)
11: SEG_H (2/3*VDD)
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Flash 8-Bit MCU with LED/LCD Driver
PDFS0 Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
PDFS03
PDFS02
PDFS01
PDFS00
R/W
—
—
—
—
R/W
R/W
R/W
R/W
POR
—
—
—
—
0
0
0
0
Bit 7~4
Unimplemented, read as "0"
Bit 3~2PDFS03~PDFS02: Port D 1 Function Selection
00: PD1/LED23
01: PD1/LED23
10: SEG_L (1/3*VDD)
11: SEG_H (2/3*VDD)
Bit 1~0PDFS01~PDFS00: Port D 0 Function Selection
00: PD0/LED22
01: PD0/LED22
10: SEG_L (1/3*VDD)
11: SEG_H (2/3*VDD)
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.
I/O Source Current Selection
The device provides 24 I/O lines with the programmable source current functions. There are four
levels source current from level 0 to level 3 selected by the PXPS1 or PXPS0 register for various
applications such as a LED matrix. Users can refer to the D.C. characteristics section to select the
desired source current level for specific applications.
Bit
Register
Name
7
6
5
4
3
2
1
0
PXFS0
PXPS07
PXPS06
PXPS05
PXPS04
PXPS03
PXPS02
PXPS01
PXPS00
PXFS1
—
—
PXPS15
PXPS14
PXPS13
PXPS12
PXPS11
PXPS10
Source Current Selection Register List
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Flash 8-Bit MCU with LED/LCD Driver
PXPS0 Register
Bit
7
6
5
4
3
2
1
0
Name
PXPS07
PXPS06
PXPS05
PXPS04
PXPS03
PXPS02
PXPS01
PXPS00
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 7~6PXPS07~PXPS06: PB7~PB4 Source Current Selection
00: Source current level 3 (max.)
01: Source current level 2
10: Source current level 1
11: Source current level 0 (min.)
Bit 5~4PXPS05~PXPS04: PB3~PB0 Source Current Selection
00: Source current level 3 (max.)
01: Source current level 2
10: Source current level 1
11: Source current level 0 (min.)
Bit 3~2PXPS03~PXPS02: PA7~PA4 Source Current Selection
00: Source current level 3 (max.)
01: Source current level 2
10: Source current level 1
11: Source current level 0 (min.)
Bit 1~0PXPS01~PXPS00: PA3 and PA0 Source Current Selection
00: Source current level 3 (max.)
01: Source current level 2
10: Source current level 1
11: Source current level 0 (min.)
PXPS1 Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
PXPS15
PXPS14
PXPS13
PXPS12
PXPS11
PXPS10
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 5~4PXPS15~PXPS14: PD1~PD0 Source Current Selection
00: Source current level 3 (max.)
01: Source current level 2
10: Source current level 1
11: Source current level 0 (min.)
Bit 3~2PXPS13~PXPS12: PC7~PC4 Source Current Selection
00: Source current level 3 (max.)
01: Source current level 2
10: Source current level 1
11: Source current level 0 (min.)
Bit 1~0PXPS11~PXPS10: PC3 ~ PC0 Source Current Selection
00: Source current level 3 (max.)
01: Source current level 2
10: Source current level 1
11: Source current level 0 (min.)
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Flash 8-Bit MCU with LED/LCD Driver
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.
Port A has the additional capability of providing wake-up functions. When the device is in the
SLEEP or IDLE Mode, various methods are available to wake the device up. One of these is a high
to low transition of any of the Port A pins. Single or multiple pins on Port A can be setup to have this
function.
   
   Generic Input/Output Structure
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Flash 8-Bit MCU with LED/LCD Driver
Timer Modules – TM
One of the most fundamental functions in any microcontroller device is the ability to control and
measure time. To implement time related functions the device includes several Timer Modules,
abbreviated to the name TM. The TMs are multi-purpose timing units and serve to provide
operations such as Timer/Counter, Input Capture, Compare Match Output and Single Pulse Output
as well as being the functional unit for the generation of PWM signals. Each of the TMs has either
two or three individual interrupts. The addition of input and output pins for each TM ensures that
users are provided with timing units with a wide and flexible range of features.
The common features of the different TM types are described here with more detailed information
provided in the individual Compact, Periodic and Enhanced TM sections.
Introduction
The device contains three TMs with each TM having a reference name of CTM, PTM, and ETM.
Each individual TM can be named as Compact Type TM, Periodic Type TM or Enhanced Type TM.
Although similar in nature, the different TM types vary in their feature complexity. The common
features to all of the Compact, Periodic and Enhanced 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.
TM Function
CTM
PTM
ETM
Timer/Counter
√
√
√
I/P Capture
—
√
√
Compare Match Output
√
√
√
PWM Channels
1
1
2
Single Pulse Output
PWM Alignment
PWM Adjustment Period & Duty
—
1
2
Edge
Edge
Edge & Centre
Duty or Period
Duty or Period
Duty or Period
TM Function Summary
TM Operation
The three different types of TM offer a diverse range of functions, from simple timing operations
to PWM signal generation. The key to understanding how the TM operates is to see it in terms of
a free running counter whose value is then compared with the value of pre-programmed internal
comparators. When the free running counter has the same value as the pre-programmed comparator,
known as a compare match situation, a TM interrupt signal will be generated which can clear the
counter and perhaps also change the condition of the TM output pin. The internal TM counter is
driven by a user selectable clock source, which can be an internal clock or an external pin.
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Flash 8-Bit MCU with LED/LCD Driver
TM Clock Source
The clock source which drives the main counter in each TM can originate from various sources. The
selection of the required clock source is implemented using the xTCK2~xTCK0 bits in the xTM
control registers where x can be C, P or E, which stands for the different types of TMs. The clock
source can be a ratio of the system clock fSYS or the internal high clock fH, the fSUB clock source or
the external xTCK pin. The xTCK pin clock source is used to allow an external signal to drive the
TM as an external clock source or for event counting.
TM Interrupts
The Compact and Periodic type TMs each have 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. As the Enhanced type TM has three internal comparators and comparator A or comparator
B or comparator P compare match functions, it consequently has three internal interrupts. 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 xTCK. The TM
input pin, is essentially a clock source for the TM and is selected using the xTCK2~xTCK0 bits in
the xTMC0 register. This external TM input pin allows an external clock source to drive the internal
TM. This external TM input pin is shared with other functions but will be connected to the internal
TM if selected using the xTCK2~xTCK0 bits. The TM input pin can be chosen to have either a
rising or falling active edge.
The TMs each have one or more output pins with the label xTP. When the TM is in the Compare
Match Output Mode, these pins can be controlled by the TM to switch to a high or low level or to
toggle when a compare match situation occurs. The external xTP output pin is also the pin where the
TM generates the PWM output waveform. As the TM output pins are pin-shared with other function,
the TM output function must first be setup using the corresponding pin shared control registers.
The corresponding bits in these control registers determine if its associated pin is to be used as an
external TM output pin or if it is to have another function.
Pin
TM Type
Input
Output
Control Registers
CTM
CTCK
CTP
PAFS1
PTM
PTCK, PTPI
PTP
PBFS0
ETM
ETCK, ETPIA, ETPIB
ETPA, ETPB
PAFS1, PBFS0
TM Input/Output Pins
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Flash 8-Bit MCU with LED/LCD Driver
TM Input/Output Pin Control Registers
Selecting to have a TM input/output or whether to retain its other shared function is implemented
by configuring the corresponding pin-shared control register. The detail definitions of the pin-shared
control registers are described in the "Pin-shared Function" section in the I/O chapter.
CTCK
CTM
CCR output
CTP
CCR inverted output
CTM Function Pin Control Block Diagram
PTCK
PTM
CCR capture input
CCR output
PTPI
PTP
CCR inverted output
PTM Function Pin Control Block Diagram
ETCK
ETM
CCRA capture input
ETPIA
CCRA output
ETPA
CCRB capture input
ETPIB
CCRB output
ETPB
CCRB inverted output
ETM Function Pin Control Block Diagram
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Flash 8-Bit MCU with LED/LCD Driver
Programming Considerations
The TM Counter Registers and the Capture/Compare CCRA and CCRB registers together with the
CCRP registers, being 10-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, CCRB 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 described above, it is
recommended to use the "MOV" instruction to access the CCRA , CCRB and CCRP low byte
registers, named xTMAL, ETMBL and PTMRPL, using the following access procedures. Accessing
the CCRA, CCRB or CCRP low byte registers without following these access procedures will result
in unpredictable values.
xTM Counter Register (Read only)
xTMDH
xTMDL
8-bit
Buffer
xTMAH
xTMAL
xTM CCRA Register (Read/Write)
ETMBH
ETMBL
ETM CCRB Register (Read/Write)
PTMRPH PTMRPL
PTM CCRP Register (Read/Write)
Data Bus
The following steps show the read and write procedures:
• Writing Data to CCRA, CCRB or CCRP
♦♦
Step 1. Write data to Low Byte xTMAL, ETMBL or PTMRPL
–– Note that here data is only written to the 8-bit buffer.
♦♦
Step 2. Write data to High Byte xTMAH, ETMBH or PTMRPH
–– Here data is written directly to the high byte registers and simultaneously data is latched
from the 8-bit buffer to the Low Byte registers.
• Reading Data from the Counter Registers and CCRA, CCRB or CCRP
Rev. 1.10
♦♦
Step 1. Read data from the High Byte xTMDH, xTMAH, ETMBH or PTMRPH
–– Here data is read directly from the High Byte registers and simultaneously data is latched
from the Low Byte register into the 8-bit buffer.
♦♦
Step 2. Read data from the Low Byte xTMDL, xTMAL, ETMBL or PTMRPL
–– This step reads data from the 8-bit buffer.
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Flash 8-Bit MCU with LED/LCD Driver
Compact Type TM – CTM
Although the simplest form of the three 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
pins.
TM Type
TM Input Pin
TM Output Pin
10-bit CTM
CTCK
CTP
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   Compact Type TM Block Diagram (n=0)
Compact TM Operation
At its core is a 10-bit count-up counter which is driven by a user selectable internal or external clock
source. There are 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 three bits wide whose value is compared with the highest three bits in the counter while the
CCRA is the ten bits and therefore compares with all counter bits.
The only way of changing the value of the 10-bit counter using the application program, is to
clear the counter by changing the CTON 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.
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Flash 8-Bit MCU with LED/LCD Driver
Compact Type TM Register Description
Overall operation of the Compact TM is controlled using six registers. A read only register pair
exists to store the internal counter 10-bit value, while a read/write register pair exists to store the
internal 10-bit CCRA value. The remaining two registers are control registers which setup the
different operating and control modes as well as the three CCRP bits.
Bit
Register
Name
7
6
5
4
3
2
1
0
CTMC0
CTPAU
CTCK2
CTCK1
CTCK0
CTON
CTRP2
CTRP1
CTRP0
CTMC1
CTM1
CTM0
CTIO1
CTIO0
CTOC
CTPOL
CTDPX
CTCCLR
CTMDL
D7
D6
D5
D4
D3
D2
D1
D0
CTMDH
—
—
—
—
—
—
D9
D8
CTMAL
D7
D6
D5
D4
D3
D2
D1
D0
CTMAH
—
—
—
—
—
—
D9
D8
Compact TM Register List (n=0)
CTMDL 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
CTMDL: CTM Counter Low Byte Register bit 7 ~ bit 0
CTM 10-bit Counter bit 7 ~ bit 0
CTMDH Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
—
—
D9
D8
R/W
—
—
—
—
—
—
R
R
POR
—
—
—
—
—
—
0
0
1
0
Bit 7~2
Unimplemented, read as "0"
Bit 1~0
CTMDH: CTM Counter High Byte Register bit 1 ~ bit 0
CTM 10-bit Counter bit 9 ~ bit 8
CTMAL Register
Bit
7
6
5
4
3
2
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
CTMAL: CTM CCRA Low Byte Register bit 7 ~ bit 0
CTM 10-bit CCRA bit 7 ~ bit 0
CTMAH Register
Rev. 1.10
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
CTMAH: CTM CCRA High Byte Register bit 1 ~ bit 0
CTM 10-bit CCRA bit 9 ~ bit 8
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Flash 8-Bit MCU with LED/LCD Driver
CTMC0 Register
Bit
7
6
5
4
3
2
1
0
Name
CTPAU
CTCK2
CTCK1
CTCK0
CTON
CTRP2
CTRP1
CTRP0
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 7CTPAU: CTM Counter Pause Control
0: Run
1: Pause
The counter can be paused by setting this bit high. Clearing the bit to zero restores
normal counter operation. When in a Pause condition the TM will remain powered up
and continue to consume power. The counter will retain its residual value when this bit
changes from low to high and resume counting from this value when the bit changes
to a low value again.
Bit 6~4 CTCK2~CTCK0: Select CTM Counter clock
000: fSYS/4
001: fSYS
010: fH/16
011: fH/64
100: fSUB
101: fSUB
110: CTCK rising edge clock
111: CTCK falling edge clock
These three bits are used to select the clock source for the TM. The external pin clock
source can be chosen to be active on the rising or falling edge. The clock source fSYS is
the system clock, while fH and fSUB are other internal clocks, the details of which can
be found in the oscillator section.
Bit 3TnON: CTM Counter On/Off Control
0: Off
1: On
This bit controls the overall on/off function of the TM. Setting the bit high enables the
counter to run, clearing the bit disables the TM. Clearing this bit to zero will stop the
counter from counting and turn off the TM which will reduce its power consumption.
When the bit changes state from low to high the internal counter value will be reset
to zero, however when the bit changes from high to low, the internal counter will
retain its residual value. If the TM is in the Compare Match Output Mode then the TM
output pin will be reset to its initial condition, as specified by the CTOC bit, when the
CTON bit changes from low to high.
Bit 2~0CTRP2~CTRP0: CTM CCRP 3-bit register, compared with the CTM Counter bit 9~bit
7 Comparator P Match Period
000: 1024 CTM clocks
001: 128 CTM clocks
010: 256 CTM clocks
011: 384 CTM clocks
100: 512 CTM clocks
101: 640 CTM clocks
110: 768 CTM clocks
111: 896 CTM clocks
These three bits are used to setup the value on the internal CCRP 3-bit register, which
are then compared with the internal counter's highest three bits. The result of this
comparison can be selected to clear the internal counter if the CTCCLR bit is set to
zero. Setting the CTCCLR bit to zero ensures that a compare match with the CCRP
values will reset the internal counter. As the CCRP bits are only compared with the
highest three counter bits, the compare values exist in 128 clock cycle multiples.
Clearing all three bits to zero is in effect allowing the counter to overflow at its
maximum value.
Rev. 1.10
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Flash 8-Bit MCU with LED/LCD Driver
CTMC1 Register
Rev. 1.10
Bit
7
6
5
4
3
2
1
0
Name
CTM1
CTM0
CTIO1
CTIO0
CTOC
CTPOL
CTDPX
CTCCLR
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
CTM1~CTM0: Select CTM 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 TM. To ensure reliable operation
the TM should be switched off before any changes are made to the CTM1 and CTM0
bits. In the Timer/Counter Mode, the TM output pin control must be disabled.
Bit 5~4
CTIO1~CTIO0: Select CTP output function
Compare Match Output Mode
00: No change
01: Output low
10: Output high
11: Toggle output
PWM 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 TM output pin changes state when a
certain condition is reached. The function that these bits select depends upon in which
mode the TM is running.
In the Compare Match Output Mode, the CTIO1 and CTIO0 bits determine how the
TM output pin changes state when a compare match occurs from the Comparator A.
The TM output pin can be setup to switch high, switch low or to toggle its present
state when a compare match occurs from the Comparator A. When the bits are both
zero, then no change will take place on the output. The initial value of the TM output
pin should be setup using the CTOC bit in the CTMC1 register. Note that the output
level requested by the CTIO1 and CTIO0 bits must be different from the initial value
setup using the CTOC bit otherwise no change will occur on the TM output pin when
a compare match occurs. After the TM output pin changes state, it can be reset to its
initial level by changing the level of the CTON bit from low to high.
In the PWM Mode, the CTIO1 and CTIO0 bits determine how the TM output pin
changes state when a certain compare match condition occurs. The PWM output
function is modified by changing these two bits. It is necessary to only change the
values of the CTIO1 and CTIO0 bits only after the TMn has been switched off.
Unpredictable PWM outputs will occur if the CTIO1 and CTIO0 bits are changed
when the TM is running.
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Flash 8-Bit MCU with LED/LCD Driver
Rev. 1.10
Bit 3
CTOC: CTP Output control bit
Compare Match Output Mode
0: Initial low
1: Initial high
PWM Mode
0: Active low
1: Active high
This is the output control bit for the TM output pin. Its operation depends upon
whether TM is being used in the Compare Match Output Mode or in the PWM Mode.
It has no effect if the TM is in the Timer/Counter Mode. In the Compare Match Output
Mode it determines the logic level of the TM output pin before a compare match
occurs. In the PWM Mode it determines if the PWM signal is active high or active
low.
Bit 2
CTPOL: CTP Output polarity Control
0: Non-invert
1: Invert
This bit controls the polarity of the CTP output pin. When the bit is set high the TM
output pin will be inverted and not inverted when the bit is zero. It has no effect if the
TM is in the Timer/Counter Mode.
Bit 1
CTDPX: CTM PWM duty/period Output Polarity 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 0
CTCCLR: Select CTM Counter clear condition
0: CTM Comparatror P match
1: CTM Comparatror 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 CTCCLR 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 CTCCLR bit is not
used in the PWM Mode.
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Flash 8-Bit MCU with LED/LCD Driver
Compact Type TM Operating 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 CTM1 and CTM0
bits in the CTMC1 register.
Compare Match Output Mode
To select this mode, bits CTM1 and CTM0 in the CTMC1 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 CTCCLR 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 CTMAF and CTMPF interrupt request flags for the
Comparator A and Comparator P respectively, will both be generated.
If the CTCCLR bit in the CTMC1 register is high then the counter will be cleared when a compare
match occurs from Comparator A. However, here only the CTMAF interrupt request flag will be
generated even if the value of the CCRP bits is less than that of the CCRA registers. Therefore when
CTCCLR is high no CTMPF interrupt request flag will be generated. If the CCRA bits are all zero,
the counter will overflow when its reaches its maximum 10-bit, 3FF Hex, value, however here the
CTMAF interrupt request flag will not be generated.
As the name of the mode suggests, after a comparison is made, the TM output pin will change state.
The TM output pin condition however only changes state when a CTMAF interrupt request flag is
generated after a compare match occurs from Comparator A. The CTMPF interrupt request flag,
generated from a compare match occurs from Comparator P, will have no effect on the TM output
pin. The way in which the TM output pin changes state are determined by the condition of the
CTIO1 and CTIO0 bits in the CTMC1 register. The TM output pin can be selected using the CTIO1
and CTIO0 bits to go high, to go low or to toggle from its present condition when a compare match
occurs from Comparator A. The initial condition of the TM output pin, which is setup after the
TnON bit changes from low to high, is setup using the CTOC bit. Note that if the CTIO1 and CTIO0
bits are zero then no pin change will take place.
Rev. 1.10
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Flash 8-Bit MCU with LED/LCD Driver
Counter Value
0x3FF
CTCCLR = 0; CTM[1:0] = 00
Counter
overflow
CCRP > 0
Counter cleared by CCRP value
CCRP = 0
Counter
Reset
Resume
CCRP > 0
CCRP
Pause
CCRA
Stop
Time
CTON
CTPAU
CTPOL
CCRP Int.
Flag CTMPF
CCRA Int.
Flag CTMAF
CTM O/P Pin
Output Pin set
to Initial Level
Low if CTOC = 0
Output Toggle
with CTMAF flag
Now CTIO[1:0] = 10
Active High Output Select
Output not affected by
CTMAF flag. Remains High
until reset by CTON bit
Output inverts
when CTPOL is high
Output Pin
Reset to initial value
Output controlled
by other pin-shared function
Here CTIO[1:0] = 11
Toggle Output Select
Compare Match Output Mode – CTCCLR=0
Note: 1. With CTCCLR=0, a Comparator P match will clear the counter
2. The TM output pin is controlled only by the CTMAF flag
3. The output pin is reset to its initial state by a CTON bit rising edge
Rev. 1.10
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Flash 8-Bit MCU with LED/LCD Driver
CTCCLR = 1; CTM[1:0] = 00
Counter Value
CCRA > 0
Counter cleared by CCRA value
0x3FF
Resume
CCRA
CCRA = 0
Counter overflow
CCRA = 0
Pause
CCRP
Stop
Counter Reset
Time
CTON
CTPAU
CTPOL
No CTMAF flag
generated on
CCRA overflow
CCRA Int.
Flag CTMAF
CCRP Int.
Flag CTMPF
CTM O/P Pin
Output does
not change
CTMPF not
generated
Output not affected by
Output Pin set
to Initial Level
Low if CTOC = 0
Output Toggle
with CTMAF flag
Output inverts
when CTPOL is high
Output Pin
Reset to initial value
Output controlled
by other pin- shared function
CTMAF flag. Remains High
Now CTIO[1:0] = 10
Active High Output Select
until reset by CTON bit
Here CTIO[1:0] = 11
Toggle Output Select
Compare Match Output Mode – CTCCLR=1
Note: 1. With CTCCLR=1, a Comparator A match will clear the counter
2. The TM output pin is controlled only by the CTMAF flag
3. The output pin is reset to its initial state by a CTON bit rising edge
4. The CTMPF flag is not generated when CTCCLR=1
Rev. 1.10
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Flash 8-Bit MCU with LED/LCD Driver
Timer/Counter Mode
To select this mode, bits CTM1 and CTM0 in the CTMC1 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 TM output
pin is not used. Therefore the above description and Timing Diagrams for the Compare Match
Output Mode can be used to understand its function. As the TM output pin is not used in this mode,
the pin can be used as a normal I/O pin or other pin-shared function.
PWM Output Mode
To selec t this mode, bits CTM1 and CTM0 in the CTMC1 register should be set to 10 respectively.
The PWM function within the TM is useful for applications which require functions such as motor
control, heating control, illumination control etc. By providing a signal of fixed frequency but
of varying duty cycle on the TM output pin, a square wave AC waveform can be generated with
varying equivalent DC RMS values.
As both the period and duty cycle of the PWM waveform can be controlled, the choice of generated
waveform is extremely flexible. In the PWM mode, the CTCCLR 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 CTDPX bit in the CTMC1 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 CTOC bit in the CTMC1 register is used to
select the required polarity of the PWM waveform while the two CTIO1 and CTIO0 bits are used to
enable the PWM output or to force the TM output pin to a fixed high or low level. The CTPOL bit is
used to reverse the polarity of the PWM output waveform.
CTM, PWM Mode, Edge-aligned Mode, CTDPX=0
CCRP
001b
010b
011b
100b
101b
110b
111b
000b
Period
128
256
384
512
640
768
896
1024
Duty
CCRA
If fSYS=16MHz, TM clock source is fSYS/4, CCRP=100b and CCRA=128,
The CTM 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%.
CTM, PWM Mode, Edge-aligned Mode, CTDPX=1
CCRP
001b
010b
011b
100b
128
256
384
512
Period
Duty
101b
110b
111b
000b
768
896
1024
CCRA
640
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 register value.
Rev. 1.10
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Flash 8-Bit MCU with LED/LCD Driver
Counter
Value
CTDPX=0; CTM[1:0]=10
Counter Cleared by CCRP
Counter reset when
CTON returns high
CCRP
Pause Resume
CCRA
Counter Stop If
CTON bit low
Time
CTON
CTPAU
CTPOL
CCRA Int.
Flag CTMAF
CCRP Int.
Flag CTMPF
CTM O/P Pin
(CTOC=1)
CTM O/P Pin
(CTOC=0)
PWM Duty Cycle
set by CCRA
Output controlled by
Other pin-shared function
PWM resumes
operation
Output Inverts
When CTPOL = 1
PWM Period
set by CCRP
PWM Mode – CTDPX=0
PWM Mode– CTDPX = 0
Note: 1. Here CTDPX=0 -- Counter cleared by CCRP
2. A counter clear sets the PWM Period
3. The internal PWM function continues running even when CTIO [1:0]=00 or 01
4. The CTCCLR bit has no influence on PWM operation
Rev. 1.10
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Flash 8-Bit MCU with LED/LCD Driver
Counter
Value
CTDPX=1; CTM[1:0]=10
Counter Cleared by CCRA
Counter reset when
CTON returns high
CCRA
Pause Resume
CCRP
Counter Stop If
CTON bit low
Time
CTON
CTPAU
CTPOL
CCRP Int.
Flag CTMPF
CCRA Int.
Flag CTMAF
CTM O/P Pin
(CTOC=1)
CTM O/P Pin
(CTOC=0)
PWM Duty Cycle
set by CCRP
Output controlled by
Other pin-shared function
PWM resumes
operation
Output Inverts
When CTPOL = 1
PWM Period
set by CCRA
PWM
Mode
– CTDPX=1
PWM
Mode
– CTDPX = 1
Note: 1. Here CTDPX =1 – Counter cleared by CCRA
2. A counter clear sets the PWM Period
3. The internal PWM function continues running even when CTIO [1:0]=00 or 01
4. The CTCCLR bit has no influence on PWM operation
Rev. 1.10
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Flash 8-Bit MCU with LED/LCD Driver
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 or two external input pins and can drive one external output pin.
TM Type
TM Input Pin
TM Output Pin
10-bit PTM
PTCK, PTPI
PTP
Periodic TM Operation
At the 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 or CCRA comparator is 10-bit wide whose value is 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 PTON bit from low to high. The counter will also be cleared
automatically by a counter overflow or a compare match with one of its associated comparators.
When these conditions occur, a TM interrupt signal will also usually be generated. The Periodic
Type TM can operate in a number of different operational modes, can be driven by different clock
sources including an input pin and can also control an output pin. All operating setup conditions are
selected using relevant internal registers.
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Periodic Type TM Block Diagram
Rev. 1.10
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HT69F240
Flash 8-Bit MCU with LED/LCD Driver
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.
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PTMC0
PTPAU
PTCK2
PTCK1
PTCK0
PTON
—
—
—
PTMC1
PTM1
PTM0
PTIO1
PTIO0
PTOC
PTPOL
PTCAPTS
PTCCLR
PTMDL
D7
D6
D5
D4
D3
D2
D1
D0
PTMDH
—
—
—
—
—
—
D9
D8
PTMAL
D7
D6
D5
D4
D3
D2
D1
D0
PTMAH
—
—
—
—
—
—
D9
D8
PTMRPL
D7
D6
D5
D4
D3
D2
D1
D0
PTMRPH
—
—
—
—
—
—
D9
D8
Periodic TM Register List
PTMDL Register
Bit
7
6
5
4
3
2
1
0
Name
D7
D6
D5
D4
D3
D2
D1
D0
R/W
R
R
R
R
R
R
R
R
POR
0
0
0
0
0
0
0
0
Bit 7~0PTMDL: PTM Counter Low Byte Register bit 7~bit 0
PTM 10-bit Counter bit 7~bit 0
PTMDH Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
—
—
D9
D8
R/W
—
—
—
—
—
—
R
R
POR
—
—
—
—
—
—
0
0
Bit 7~2
Unimplemented, read as "0"
Bit 1~0
PTMDH: PTM Counter High Byte Register bit 1~bit 0
PTM 10-bit Counter bit 9~bit 8
PTMAL Register
Bit
7
6
5
4
3
2
1
0
Name
D7
D6
D5
D4
D3
D2
D1
D0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~0PTMAL: PTM CCRA Low Byte Register bit 7~bit 0
PTM 10-bit CCRA bit 7~bit 0
Rev. 1.10
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Flash 8-Bit MCU with LED/LCD Driver
PTMAH 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 1~0PTMAH: PTM CCRA High Byte Register bit 1~bit 0
PTM 10-bit CCRA bit 9~bit 8
PTMRPL Register
Bit
7
6
5
4
3
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 PTMRPL: PTM CCRP Low Byte Registger bit 7 ~ bit 0
PTM 10-bit CCRP bit 7 ~ bit 0
PTMRPH Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
—
—
D9
D8
R/W
—
—
—
—
—
—
R/W
R/W
POR
—
—
—
—
—
—
0
0
Bit 7~2 Unimplemented, read as "0"
Bit 1~0 PTMRPH: PTM CCRP High Byte Registger bit 1 ~ bit 0
PTM 10-bit CCRP bit 9 ~ bit 8
PTMC0 Register
Bit
7
6
5
4
3
2
1
0
Name
PTPAU
PTCK2
PTCK1
PTCK0
PTON
—
—
—
R/W
R/W
R/W
R/W
R/W
R/W
—
—
—
POR
0
0
0
0
0
—
—
—
Bit 7PTPAU: PTM Counter Pause Control
0: Run
1: Pause
The counter can be paused by setting this bit high. Clearing the bit to zero restores
normal counter operation. When in a Pause condition the TM will remain powered up
and continue to consume power. The counter will retain its residual value when this bit
changes from low to high and resume counting from this value when the bit changes
to a low value again.
Bit 6~4PTCK2~PTCK0: Select PTM Counter clock
000: fSYS/4
001: fSYS
010: fH/16
011: fH/64
100: fSUB
101: fSUB
110: PTCK rising edge clock
111: PTCK falling edge clock
These three bits are used to select the clock source for the TM. The external pin clock
source can be chosen to be active on the rising or falling edge. The clock source fSYS is
the system clock, while fH and fSUB are other internal clocks, the details of which can
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Flash 8-Bit MCU with LED/LCD Driver
be found in the oscillator section.
Bit 3PTON: PTM Counter On/Off Control
0: Off
1: On
This bit controls the overall on/off function of the TM. Setting the bit high enables the
counter to run, clearing the bit disables the TM. Clearing this bit to zero will stop the
counter from counting and turn off the TM which will reduce its power consumption.
When the bit changes state from low to high the internal counter value will be reset to
zero, however when the bit changes from high to low, the internal counter will retain
its residual value until the bit returns high again. If the TM is in the Compare Match
Output Mode then the TM output pin will be reset to its initial condition, as specified
by the T2OC bit, when the PTOC bit changes from low to high.
Bit 2~0
Unimplemented, read as "0"
PTMC1 Register
Bit
7
6
5
4
3
2
Name
PTM1
PTM0
PTIO1
PTIO0
PTOC
PTPOL
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
PTCAPTS PTCCLR
Bit 7~6PTM1~PTM0: Select PTM 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 TM. To ensure reliable operation
the TM should be switched off before any changes are made to the PTM1 and PTM2
bits. In the Timer/Counter Mode, the TM output pin control must be disabled.
Bit 5~4PTIO1~PTIO0: Select PTP output function
Compare Match Output Mode
00: No change
01: Output low
10: Output high
11: Toggle output
PWM Mode/Single Pulse Output Mode
00: PWM output inactive state
01: PWM output active state
10: PWM output
11: Single pulse output
Capture Input Mode
00: Input capture at rising edge of PTPI or PTCK
01: Input capture at falling edge of PTPI or PTCK
10: Input capture at falling/rising edge of PTPI or PTCK
11: Input capture disabled
Timer/counter Mode
Unused
These two bits are used to determine how the TM output pin changes state when a
certain condition is reached. The function that these bits select depends upon in which
mode the TM is running.
In the Compare Match Output Mode, the PTIO1 and PTIO0 bits determine how the
TM output pin changes state when a compare match occurs from the Comparator A.
The TM output pin can be setup to switch high, switch low or to toggle its present
state when a compare match occurs from the Comparator A. When the bits are both
zero, then no change will take place on the output. The initial value of the TM output
pin should be setup using the PTOC bit in the PTMC1 register. Note that the output
level requested by the PTIO1 and PTIO0 bits must be different from the initial value
setup using the PTOC bit otherwise no change will occur on the TM output pin when
a compare match occurs. After the TM output pin changes state, it can be reset to its
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Flash 8-Bit MCU with LED/LCD Driver
initial level by changing the level of the PTON bit from low to high.
In the PWM Mode, the PTIO1 and PTIO0 bits determine how the TM output pin
changes state when a certain compare match condition occurs. The PWM output
function is modified by changing these two bits. It is necessary to only change the
values of the PTIO1 and PTIO0 bits only after the TMn has been switched off.
Unpredictable PWM outputs will occur if the PTIO1 and PTIO0 bits are changed
when the TM is running.
Bit 3PTOC: PTP Output control bit
Compare Match Output Mode
0: Initial low
1: Initial high
PWM Mode/Single Pulse Output Mode
0: Active low
1: Active high
This is the output control bit for the TM output pin. Its operation depends upon
whether TM is being used in the Compare Match Output Mode or in the PWM Mode/
Single Pulse Output Mode. It has no effect if the TM is in the Timer/Counter Mode. In
the Compare Match Output Mode it determines the logic level of the TM output pin
before a compare match occurs. In the PWM Mode it determines if the PWM signal is
active high or active low.
Bit 2PTPOL: PTP Output polarity Control
0: Non-invert
1: Invert
This bit controls the polarity of the PTP output pin. When the bit is set high the TM
output pin will be inverted and not inverted when the bit is zero. It has no effect if the
TM is in the Timer/Counter Mode.
Bit 1PTCAPTS: PTM Capture trigger source select
0: From PTPI pin
1: From PTCK pin
Bit 0PTCCLR: Select PTM Counter clear condition
0: PTM Comparator P match
1: PTM 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 PTCCLR bit set high,
the counter will be cleared when a compare match occurs from the Comparator A.
When the bit is low, the counter will be cleared when a compare match occurs from
the Comparator P or with a counter overflow. A counter overflow clearing method can
only be implemented if the CCRP bits are all cleared to zero. The PTCCLR bit is not
used in the PWM, Single Pulse or Input Capture Mode.
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Flash 8-Bit MCU with LED/LCD Driver
Periodic Type TM Operating Modes
The Periodic Type TM can operate in one of five operating modes, Compare Match Output Mode,
PWM Output Mode, Single Pulse Output Mode, Capture Input Mode or Timer/Counter Mode. The
operating mode is selected using the PTM1 and PTM0 bits in the PTMC1 register.
Compare Output Mode
To select this mode, bits PTM1 and PTM0 in the PTMC1 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 PTCCLR 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 PTMAF and PTMPF interrupt request flags for Comparator A and
Comparator P respectively, will both be generated.
If the PTCCLR bit in the PTMC1 register is high then the counter will be cleared when a compare
match occurs from Comparator A. However, here only the PTMAF interrupt request flag will be
generated even if the value of the CCRP bits is less than that of the CCRA registers. Therefore when
PTCCLR is high no PTMPF interrupt request flag will be generated. In the Compare Match Output
Mode, the CCRA can not be set to "0".
As the name of the mode suggests, after a comparison is made, the TM output pin, will change state.
The TM output pin condition however only changes state when a PTMAF interrupt request flag is
generated after a compare match occurs from Comparator A. The PTMPF interrupt request flag,
generated from a compare match occurs from Comparator P, will have no effect on the TM output
pin. The way in which the TM output pin changes state are determined by the condition of the
PTIO1 and PTIO0 bits in the PTMC1 register. The TM output pin can be selected using the PTIO1
and PTIO0 bits to go high, to go low or to toggle from its present condition when a compare match
occurs from Comparator A. The initial condition of the TM output pin, which is setup after the
PTON bit changes from low to high, is setup using the PTOC bit. Note that if the PTIO1 and PTIO0
bits are zero then no pin change will take place.
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Flash 8-Bit MCU with LED/LCD Driver
Counter Value
Counter overflow
CCRP=0
0x3FF
PTCCLR = 0; PTM [1:0] = 00
CCRP > 0
Counter cleared by CCRP value
CCRP > 0
Counter
Restart
Resume
CCRP
Pause
CCRA
Stop
Time
PTON
PTPAU
PTPOL
CCRP Int. Flag
PTMPF
CCRA Int. Flag
PTMAF
PTM
O/P Pin
Output pin set to
initial Level Low
if PTOC=0
Output not affected by
PTMAF flag. Remains High
until reset by PTON bit
Output Toggle with
PTMAF flag
Here PTIO [1:0] = 11
Toggle Output select
Note PTIO [1:0] = 10
Active High Output select
Output Inverts
when PTPOL is high
Output Pin
Reset to Initial value
Output controlled by
other pin-shared function
Compare Match Output Mode – PTCCLR = 0
Note: 1. With PTCCLR=0, a Comparator P match will clear the counter
2. The TM output pin is controlled only by the PTMAF flag
3. The output pin is reset to its initial state by a PTON bit rising edge
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Flash 8-Bit MCU with LED/LCD Driver
Counter Value
PTCCLR = 1; PTM [1:0] = 00
CCRA = 0
Counter overflow
CCRA > 0 Counter cleared by CCRA value
0x3FF
CCRA=0
Resume
CCRA
Pause
Stop
Counter Restart
CCRP
Time
PTON
PTPAU
PTPOL
No PTMAF flag
generated on
CCRA overflow
CCRA Int. Flag
PTMAF
CCRP Int. Flag
PTMPF
PTM
O/P Pin
PTMPF not
generated
Output pin set to
initial Level Low
if PTOC=0
Output does
not change
Output not affected by
PTMAF flag. Remains High
until reset by PTON bit
Output Toggle with
PTMAF flag
Here PTIO [1:0] = 11
Toggle Output select
Note PTIO [1:0] = 10
Active High Output select
Output Inverts
when PTPOL is high
Output Pin
Reset to Initial value
Output controlled by
other pin-shared function
Compare Match Output Mode – PTCCLR = 1
Note: 1. With PTCCLR=1, a Comparator A match will clear the counter
2. The TM output pin is controlled only by the PTMAF flag
3. The output pin is reset to its initial state by a PTON bit rising edge
4. A PTMPF flag is not generated when PTCCLR =1
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Flash 8-Bit MCU with LED/LCD Driver
Timer/Counter Mode
To select this mode, bits PTM1 and PTM0 in the PTMC1 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 TM output
pin is not used. Therefore the above description and Timing Diagrams for the Compare Match
Output Mode can be used to understand its function. As the TM output pin is not used in this mode,
the pin can be used as a normal I/O pin or other pin-shared function.
PWM Output Mode
To select this mode, bits PTM1 and PTM0 in the PTMC1 register should be set to 10 respectively
and also the PTIO1 and PTIO0 bits should be set to 10 respectively. The PWM function within
the TM is useful for applications which require functions such as motor control, heating control,
illumination control etc. By providing a signal of fixed frequency but of varying duty cycle on the
TM output pin, a square wave AC waveform can be generated with varying equivalent DC RMS
values.
As both the period and duty cycle of the PWM waveform can be controlled, the choice of generated
waveform is extremely flexible. In the PWM mode, the PTCCLR bit has no effect as the PWM
period. Both of the 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. The PWM waveform frequency and duty cycle can therefore
be controlled by the values in the CCRA and CCRP registers.
An interrupt flag, one for each of the CCRA and CCRP, will be generated when a compare match
occurs from either Comparator A or Comparator P. The PTOC bit in the PTMC1 register is used to
select the required polarity of the PWM waveform while the two PTIO1 and PTIO0 bits are used to
enable the PWM output or to force the TM output pin to a fixed high or low level. The PTPOL bit is
used to reverse the polarity of the PWM output waveform.
PTM, PWM Mode, Edge-aligned Mode
Period
CCRP=0
→ Period = 1024
Duty
CCRP=1~1023
→ Period = 1~1023
CCRA
If fSYS=16MHz, TM clock source select fSYS/4, CCRP=512 and CCRA=128,
The PTM 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%.
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Flash 8-Bit MCU with LED/LCD Driver
Counter Value
PTnM [1:0] = 10
Counter cleared
by CCRP
Counter Reset when
PTON returns high
CCRP
Pause Resume
CCRA
Counter Stop if
PTON bit low
Time
PTON
PTPAU
PTPOL
CCRA Int. Flag
PTMAF
CCRP Int. Flag
PTMPF
PTM O/P Pin
(PTOC=1)
PTM O/P Pin
(PTOC=0)
PWM Duty Cycle
set by CCRA
PWM Period
set by CCRP
PWM resumes
operation
Output controlled by
Output Inverts
other pin-shared function
When PTPOL = 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 PTIO [1:0] = 00 or 01
4. The PTCCLR bit has no influence on PWM operation
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Flash 8-Bit MCU with LED/LCD Driver
Single Pulse Output Mode
To select this mode, bits PTM1 and PTM0 in the PTMC1 register should be set to 10 respectively
and also the PTIO1 and PTIO0 bits should be set to 11 respectively. The Single Pulse Output Mode,
as the name suggests, will generate a single shot pulse on the TM output pin.
The trigger for the pulse output leading edge is a low to high transition of the PTON bit, which can
be implemented using the application program. However in the Single Pulse Mode, the PTON bit
can also be made to automatically change from low to high using the external PTCK pin, which will
in turn initiate the Single Pulse output. When the PTON bit transitions to a high level, the counter
will start running and the pulse leading edge will be generated. The PTON bit should remain high
when the pulse is in its active state. The generated pulse trailing edge will be generated when the
PTON bit is cleared to zero, which can be implemented using the application program or when a
compare match occurs from Comparator A.
However a compare match from Comparator A will also automatically clear the PTON bit and thus
generate the Single Pulse output trailing edge. In this way the CCRA value can be used to control
the pulse width. A compare match from Comparator A will also generate a TM interrupt. The counter
can only be reset back to zero when the PTON bit changes from low to high when the counter
restarts. In the Single Pulse Mode CCRP is not used. The PTCCLR bit is not used in this Mode.
S/W Command
SET“PTON”
or
PTCK Pin
Transition
CCRA
Leading Edge
CCRA
Trailing Edge
PTON bit
0à1
PTON bit
1à0
S/W Command
CLR“PTON”
or
CCRA Compare
Match
PTP Output Pin
Pulse Width = CCRA Value
Single Pulse Generation
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Flash 8-Bit MCU with LED/LCD Driver
Counter Value
PTM [1:0] = 10 ; PTIO [1:0] = 11
Counter stopped
by CCRA
Counter Reset when
PTON returns high
CCRA
Pause
Counter Stops
by software
Resume
CCRP
Time
PTON
Software
Trigger
Auto. set by
PTCK pin
Cleared by
CCRA match
PTCK pin
Software
Trigger
Software
Trigger
Software
Software Trigger
Clear
PTCK pin
Trigger
PTPAU
PTPOL
No CCRP Interrupts
generated
CCRP Int. Flag
PTMPF
CCRA Int. Flag
PTMAF
PTM O/P Pin
(PTOC=1)
PTM O/P Pin
(PTOC=0)
Output Inverts
when PTPOL = 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 PTCK pin or by setting the PTON bit high
4. A PTCK pin active edge will automatically set the PTON bit high.
5. In the Single Pulse Mode, PTIO [1:0] must be set to "11" and can not be changed.
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Flash 8-Bit MCU with LED/LCD Driver
Capture Input Mode
To select this mode bits PTM1 and PTM0 in the PTMC1 register should be set to 01 respectively. This
mode enables external signals to capture and store the present value of the internal counter and can
therefore be used for applications such as pulse width measurements. The external signal is supplied on
the PTPI or PTCK pin, selected by the PTCAPTS bit in the PTMC0 register. The capture input pin active
edge can be either a rising edge, a falling edge or both rising and falling edges; the active edge transition
type is selected using the PTIO1 and PTIO0 bits in the PTMC1 register. The counter is started when the
PTON bit changes from low to high which is initiated using the application program.
When the required edge transition appears on the PTPI or PTCK pin the present value in the counter will
be latched into the CCRA registers and a TM interrupt generated. Irrespective of what events occur on
the PTPI or PTCK pin the counter will continue to free run until the PTON bit changes from high to low.
When a CCRP compare match occurs the counter will reset back to zero; in this way the CCRP value can
be used to control the maximum counter value. When a CCRP compare match occurs from Comparator P,
a TM interrupt will also be generated. Counting the number of overflow interrupt signals from the CCRP
can be a useful method in measuring long pulse widths. The PTIO1 and PTIO0 bits can select the active
trigger edge on the PTPI or PTCK pin to be a rising edge, falling edge or both edge types. If the PTIO1
and PTIO0 bits are both set high, then no capture operation will take place irrespective of what happens
on the PTPI or PTCK pin, however it must be noted that the counter will continue to run.
As the PTPI or PTCK pin is pin shared with other functions, care must be taken if the TM is in the
Capture Input Mode. This is because if the pin is setup as an output, then any transitions on this pin may
cause an input capture operation to be executed. The PTCCLR, PTOC and PTPOL bits are not used in
this Mode.
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Flash 8-Bit MCU with LED/LCD Driver
Counter Value
PTM [1:0] = 01
Counter cleared
by CCRP
Counter Counter
Stop
Reset
CCRP
YY
Pause
Resume
XX
Time
PTON
PTPAU
Active
edge
Active
edge
PTM capture pin
PTPI or PTCK
Active edge
CCRA Int. Flag
PTMAF
CCRP Int. Flag
PTMPF
CCRA
Value
PTIO [1:0]
Value
XX
00 – Rising edge
YY
01 – Falling edge
XX
10 – Both edges
YY
11 – Disable Capture
Capture Input Mode
Note: 1. PTM [1:0] = 01 and active edge set by the PTIO [1:0] bits
2. A TM Capture input pin active edge transfers the counter value to CCRA
3. PTCCLR bit not used
4. No output function – PTOC and PTPOL bits are not used
5. CCRP determines the counter value and the counter has a maximum count value when CCRP is equal to
zero.
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Flash 8-Bit MCU with LED/LCD Driver
Enhanced Type TM – ETM
The Enhanced Type TM contains five operating modes, which are Compare Match Output,
Timer/Event Counter, Capture Input, Single Pulse Output and PWM Output modes. The Enhanced
TM can also be controlled with an external input pin and can drive two external output pins.
TM Type
TM Input Pin
TM Output Pin
10-bit ETM
ETCK, ETPIA. ETPIB
ETPA, ETPB
Enhanced TM Operation
At its core is a 10-bit count-up/count-down counter which is driven by a user selectable internal
or external clock source. There are three internal comparators with the names, Comparator A,
Comparator B and Comparator P. These comparators will compare the value in the counter with the
CCRA, CCRB and CCRP registers. The CCRP comparator is 3-bits wide whose value is compared
with the highest 3-bits in the counter while CCRA and CCRB are 10-bits wide and therefore
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 ETON 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 Enhanced
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 output pins. All operating setup conditions are
selected using relevant internal registers.
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Enhanced Type TM Block Diagram
Rev. 1.10
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Flash 8-Bit MCU with LED/LCD Driver
Enhanced Type TM Register Description
Overall operation of the Enhanced 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 CCRB value. The remaining three registers are control registers which
setup the different operating and control modes as well as the three CCRP bits.
Name
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
ETMC0
ETPAU
ETCK2
ETCK1
ETCK0
ETON
ETRP2
ETRP1
ETRP0
ETCDN
ETCCLR
ETMC1
ETAM1
ETAM0
ETAIO1
ETAIO0
ETAOC
ETAPOL
ETMC2
ETBM1
ETBM0
ETBIO1
ETBIO0
ETBOC
ETBPOL ETPWM1 ETPWM0
ETMDL
D7
D6
D5
D4
D3
D2
D1
D0
ETMDH
—
—
—
—
—
—
D9
D8
ETMAL
D7
D6
D5
D4
D3
D2
D1
D0
ETMAH
—
—
—
—
—
—
D9
D8
ETMBL
D7
D6
D5
D4
D3
D2
D1
D0
ETMBH
—
—
—
—
—
—
D9
D8
Enhanced TM Register List
ETMC0 Register
Bit
7
6
5
4
3
2
1
0
Name
ETPAU
ETCK2
ETCK1
ETCK0
ETON
ETRP2
ETRP1
ETRP0
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 7ETPAU: ETM Counter Pause Control
0: Run
1: Pause
The counter can be paused by setting this bit high. Clearing the bit to zero restores
normal counter operation. When in a Pause condition the TM will remain powered up
and continue to consume power. The counter will retain its residual value when this bit
changes from low to high and resume counting from this value when the bit changes
to a low value again.
Bit 6~4 ETCK2~ETCK0: Select ETM Counter clock
000: fSYS/4
001: fSYS
010: fH/16
011: fH/64
100: fSUB
101: fSUB
110: ETCK rising edge clock
111: ETCK falling edge clock
These three bits are used to select the clock source for the TM. The external pin clock
source can be chosen to be active on the rising or falling edge. The clock source fSYS is
the system clock, while fH and fSUB are other internal clocks, the details of which can
be found in the oscillator section.
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Flash 8-Bit MCU with LED/LCD Driver
Bit 3ETON: ETM Counter On/Off Control
0: Off
1: On
This bit controls the overall on/off function of the TM. Setting the bit high enables the
counter to run, clearing the bit disables the TM. Clearing this bit to zero will stop the
counter from counting and turn off the TM which will reduce its power consumption.
When the bit changes state from low to high the internal counter value will be reset to
zero, however when the bit changes from high to low, the internal counter will retain
its residual value until the bit returns high again.
If the TM is in the Compare Match Output Mode then the TM output pins will be reset
to initial conditions, as specified by the ETAOC or ETBOC bit, when the ETON bit
changes from low to high.
Bit 2~0
Rev. 1.10
ETRP2~ETRP0: ETM CCRP 3-bit register, compared with the ETM Counter bit 9~bit 7
Comparator P Match Period
000: 1024 ETM clocks
001: 128 ETM clocks
010: 256 ETM clocks
011: 384 ETM clocks
100: 512 ETM clocks
101: 640 ETM clocks
110: 768 ETM clocks
111: 896 ETM clocks
These three bits are used to setup the value on the internal CCRP 3-bit register, which
are then compared with the internal counter highest three bits. The result of this
comparison can be selected to clear the internal counter if the ETCCLR bit is set to
zero. Setting the ETCCLR bit to zero ensures that a compare match with the CCRP
values will reset the internal counter. As the CCRP bits are only compared with the
highest three counter bits, the compare values exist in 128 clock cycle multiples.
Clearing all three bits to zero is in effect allowing the counter to overflow at its
maximum value.
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Flash 8-Bit MCU with LED/LCD Driver
ETMC1 Register
Bit
7
6
5
4
3
2
1
0
Name
ETAM1
ETAM0
ETAIO1
ETAIO0
ETAOC
ETAPOL
ETCDN
ETCCLR
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~6ETAM1~ETAM0: Select ETM CCRA 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 TM. To ensure reliable operation
the TM should be switched off before any changes are made to the ETAM1 and
ETAM0 bits. In the Timer/Counter Mode, the TM output pin is not used.
Bit 5~4ETAIO1~ETAIO0: Select ETPA or ETPIA pin output function
Compare Match Output Mode
00: No change
01: Output low
10: Output high
11: Toggle output
PWM Mode/Single Pulse Output Mode
00: PWM output inactive state
01: PWM output active state
10: PWM output
11: Single pulse output
Capture Input Mode
00: Input capture at rising edge of ETPIA
01: Input capture at falling edge of ETPIA
10: Input capture at falling/rising edge of ETPIA
11: Input capture disabled
Timer/counter Mode
Unused
These two bits are used to determine how the TM output pin changes state when a
certain condition is reached. The function that these bits select depends upon in which
mode the TM is running.
In the Compare Match Output Mode, the ETAIO1 and ETAIO0 bits determine how
the TM output pin changes state when a compare match occurs from the Comparator
A. The TM output pin can be setup to switch high, switch low or to toggle its present
state when a compare match occurs from the Comparator A. When the bits are both
zero, then no change will take place on the output. The initial value of the TM output
pin should be setup using the ETAOC bit in the ETMC1 register. Note that the output
level requested by the ETAIO1 and ETAIO0 bits must be different from the initial
value setup using the ETAOC bit otherwise no change will occur on the TM output pin
when a compare match occurs. After the TM output pin changes state, it can be reset
to its initial level by changing the level of the ETON bit from low to high.
In the PWM Mode, the ETAIO1 and ETAIO0 bits determine how the TM output
pin changes state when a certain compare match condition occurs. The PWM output
function is modified by changing these two bits. It is necessary to only change the
values of the ETAIO1 and ETAIO0 bits only after the TMn has been switched off.
Unpredictable PWM outputs will occur if the ETAIO1 and ETAIO0 bits are changed
when the TM is running.
Rev. 1.10
95
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Bit 3ETAOC: ETPA Output control bit
Compare Match Output Mode
0: Initial low
1: Initial high
PWM Mode/Single Pulse Output Mode
0: Active low
1: Active high
This is the output control bit for the ETPA output pin. Its operation depends upon
whether TM is being used in the Compare Match Output Mode or in the PWM Mode/
Single Pulse Output Mode. It has no effect if the TM is in the Timer/Counter Mode. In
the Compare Match Output Mode it determines the logic level of the TM output pin
before a compare match occurs. In the PWM Mode it determines if the PWM signal is
active high or active low.
Bit 2ETAPOL: ETPA Output polarity Control
0: Non-invert
1: Invert
This bit controls the polarity of the ETPA output pin. When the bit is set high the TM
output pin will be inverted and not inverted when the bit is zero. It has no effect if the
TM is in the Timer/Counter Mode.
Bit 1ETCDN: ETM Counter count up or down flag
0: Count up
1: Count down
Bit 0ETCCLR: Select ETM Counter clear condition
0: ETM Comparator P match
1: ETM Comparator A match
This bit is used to select the method which clears the counter. Remember that
the Enhanced TM contains three comparators, Comparator A, Comparator B and
Comparator P, but only Comparator A or Comparator P can be selected to clear the
internal counter. With the ETCCLR 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 ETCCLR bit is not used in the Single Pulse Output or
Capture Input Mode.
Rev. 1.10
96
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
ETMC2 Register
Bit
7
6
5
4
3
Name
ETBM1
ETBM0
ETBIO1
ETBIO0
ETBOC
2
1
0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R
R/W
POR
0
0
0
0
0
0
0
0
ETBPOL ETPWM1 ETPWM0
Bit 7~6ETBM1~ETBM0: Select ETM CCRB 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 TM. To ensure reliable operation
the TM should be switched off before any changes are made to the ETBM1 and
ETBM0 bits. In the Timer/Counter Mode, the TM output pin control must is not used.
Bit 5~4ETBIO1~ETBIO0: Select ETPB or ETPIB pin output function
Compare Match Output Mode
00: No change
01: Output low
10: Output high
11: Toggle output
PWM Mode/Single Pulse Output Mode
00: PWM Output inactive state
01: PWM Output active state
10: PWM output
11: Single pulse output
Capture Input Mode
00: Input capture at rising edge of ETPIB
01: Input capture at falling edge of ETPIB
10: Input capture at falling/rising edge of ETPIB
11: Input capture disabled
Timer/counter Mode
Unused
These two bits are used to determine how the TM output pin changes state when a
certain condition is reached. The function that these bits select depends upon in which
mode the TM is running.
In the Compare Match Output Mode, the ETBIO1 and ETBIO0 bits determine how
the TM output pin changes state when a compare match occurs from the Comparator
A. The TM output pin can be setup to switch high, switch low or to toggle its present
state when a compare match occurs from the Comparator A. When the bits are both
zero, then no change will take place on the output. The initial value of the TM output
pin should be setup using the ETBOC bit in the ETMC2 register. Note that the output
level requested by the ETBIO1 and ETBIO0 bits must be different from the initial
value setup using the ETBOC bit otherwise no change will occur on the TM output pin
when a compare match occurs. After the TM output pin changes state, it can be reset
to its initial level by changing the level of the ETON bit from low to high.
In the PWM Mode, the ETBIO1 and ETBIO0 bits determine how the TM output
pin changes state when a certain compare match condition occurs. The PWM output
function is modified by changing these two bits. It is necessary to only change the
values of the ETBIO1 and ETBIO0 bits only after the TMn has been switched off.
Unpredictable PWM outputs will occur if the ETBIO1 and ETBIO0 bits are changed
when the TM is running.
Rev. 1.10
97
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Bit 3ETBOC: ETPB Output control bit
Compare Match Output Mode
0: Initial low
1: Initial high
PWM Mode/Single Pulse Output Mode
0: Active low
1: Active high
This is the output control bit for the ETPB output pin. Its operation depends upon
whether TM is being used in the Compare Match Output Mode or in the PWM Mode/
Single Pulse Output Mode. It has no effect if the TM is in the Timer/Counter Mode. In
the Compare Match Output Mode it determines the logic level of the TM output pin
before a compare match occurs. In the PWM Mode it determines if the PWM signal is
active high or active low.
Bit 2ETBPOL: ETPB Output polarity Control
0: Non-invert
1: Invert
This bit controls the polarity of the ETPB output pin. When the bit is set high the TM
output pin will be inverted and not inverted when the bit is zero. It has no effect if the
TM is in the Timer/Counter Mode.
Bit 1~0ETPWM1~ETPWM0: Select ETM PWM mode
00: Edge aligned
01: Centre aligned, compare match on count up
10: Centre aligned, compare match on count down
11: Centre aligned, compare match on count up or down
ETMDL 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 7~0ETMDL: ETM Counter Low Byte Register bit 7~bit 0
ETM 10-bit Counter bit 7~bit 0
ETMDH Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
—
—
D9
D8
R/W
—
—
—
—
—
—
R
R
POR
—
—
—
—
—
—
0
0
Bit 7~2
Unimplemented, read as "0"
Bit 1~0ETMDH: ETM Counter High Byte Register bit 1~bit 0
ETM 10-bit Counter bit 9~bit 8
Rev. 1.10
98
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
ETMAL 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 7~0ETMAL: ETM CCRA Low Byte Register bit 7~bit 0
ETM 10-bit CCRA bit 7~bit 0
ETMAH Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
—
—
D9
D8
R/W
—
—
—
—
—
—
R/W
R/W
POR
—
—
—
—
—
—
0
0
2
1
0
Bit 7~2
Unimplemented, read as "0"
Bit 1~0ETMAH: ETM CCRA High Byte Register bit 1~bit 0
ETM 10-bit CCRA bit 9~bit 8
ETMBL Register
Bit
7
6
5
4
3
Name
D7
D6
D5
D4
D3
D2
D1
D0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~0ETMBL: ETM CCRB Low Byte Register bit 7~bit 0
ETM 10-bit CCRB bit 7~bit 0
ETMBH 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 1~0ETMBH: ETM CCRB High Byte Register bit 1~bit 0
ETM 10-bit CCRB bit 9~bit 8
Rev. 1.10
99
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Enhanced Type TM Operating Modes
The Enhanced 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 ETAM1 and ETAM0 bits in the ETMC1, and the ETBM1 and
ETBM0 bits in the ETMC2 register.
CCRA Compare
Match Output
Mode
CCRA
Timer/
Counter
Mode
CCRA
PWM
Output
Mode
CCRA
Single
Pulse
Output
Mode
CCRA
Input
Capture
Mode
CCRB Compare Match
Output Mode
√
—
—
—
—
CCRB Timer/Counter Mode
—
√
—
—
—
CCRB PWM Output Mode
—
—
√
—
—
CCRB Single Pulse Output
Mode
—
—
—
√
—
CCRB Input Capture Mode
—
—
—
—
√
ETM Operating Mode
"√": permitted; "—": not permitt
Compare Output Mode
To select this mode, bits ETAM1, ETAM0 and ETBM1, ETBM0 in the ETMC1/ETMC2 registers
should be all cleared to zero. 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 ETCCLR bit is low, there are two ways in which the
counter can be cleared. One is when a compare match occurs from Comparator P, the other is when
the CCRP bits are all zero which allows the counter to overflow. Here both the ETMAF and ETMPF
interrupt request flags for Comparator A and Comparator P respectively, will both be generated.
If the ETCCLR bit in the ETMC1 register is high then the counter will be cleared when a compare
match occurs from Comparator A. However, here only the ETMAF interrupt request flag will be
generated even if the value of the CCRP bits is less than that of the CCRA registers. Therefore when
ETCCLR is high no ETMPF interrupt request flag will be generated.
As the name of the mode suggests, after a comparison is made, the TM output pin, will change state.
The TM output pin condition however only changes state when a ETMAF or ETMBF interrupt
request flag is generated after a compare match occurs from Comparator A or Comparator B. The
ETMPF interrupt request flag, generated from a compare match from Comparator P, will have no
effect on the TM output pin. The way in which the TM output pin changes state is determined by the
condition of the ETAIO1 and ETAIO0 bits in the ETMC1 register for ETM CCRA, and the ETBIO1
and ETBIO0 bits in the ETMC2 register for ETM CCRB. The TM output pin can be selected
using the ETAIO1, ETAIO0 bits (for the ETPA pin) and ETBIO1, ETBIO0 bits (for the ETPB pin)
to go high, to go low or to toggle from its present condition when a compare match occurs from
Comparator A or a compare match occurs from Comparator B. The initial condition of the TM
output pin, which is setup after the ETON bit changes from low to high, is setup using the ETAOC
or ETBOC bit for ETPA or ETPB output pin. Note that if the ETAIO1, ETAIO0 and ETBIO1,
ETBIO0 bits are zero then no pin change will take place.
Rev. 1.10
100
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
0x3FF
ETCCLR = 0; ETAM[1:0] = 00
Counter
overflow
Counter Value
CCRP > 0
Counter cleared by CCRP value
CCRP = 0
Counter
Reset
Resume
CCRP > 0
CCRP
Pause
CCRA
Stop
Time
ETON
ETPAU
ETAPOL
CCRP Int.
Flag ETMPF
CCRA Int.
Flag ETMAF
ETPA O/P Pin
Output Pin set
to Initial Level
Low if ETAOC = 0
Output Toggle
with ETMAF flag
Now ETAIO[1:0] = 10
Active High Output Select
Output inverts
when ETAPOL is high
Output Pin
Reset to initial value
Output not affected by
ETMAF flag. Remains High
until reset by ETON bit
Output controlled
by other pin - shared function
Here ETAIO[1:0] = 11
Toggle Output Select
ETM CCRA Compare Match Output Mode – ETCCLR=0
Note: 1. With ETCCLR=0, a Comparator P match will clear the counter
2. The ETPA output pin is controlled only by the ETMAF flag
3. The output pin is reset to its initial state by a ETON bit rising edge
Rev. 1.10
101
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
0x3FF
ETCCLR = 0; ETBM[1:0] = 00
Counter
overflow
Counter Value
CCRP > 0
Counter cleared by CCRP value
CCRP = 0
Counter
Reset
Resume
CCRP > 0
CCRP
Pause
CCRB
Stop
Time
ETON
ETPAU
ETBPOL
CCRP Int.
Flag ETMPF
CCRB Int.
Flag ETMBF
ETPB O/P Pin
Output Pin set
to Initial Level
Low if ETBOC = 0
Output Toggle
with ETMBF flag
Now ETBIO [1:0] = 10
Active High Output Select
Output inverts
when ETBPOL is high
Output Pin
Reset to initial value
Output not affected by
ETMBF flag. Remains High
until reset by ETON bit
Output controlled
by other pin - shared function
Here ETBIO [1:0] = 11
Toggle Output Select
ETM CCRB Compare Match Output Mode – ETCCLR=0
Note: 1. With ETCCLR=0, a Comparator P match will clear the counter
2. The ETPB output pin is controlled only by the ETMBF flag
3. The output pin is reset to its initial state by a ETON bit rising edge
Rev. 1.10
102
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
ETCCLR = 1; ETAM [1:0] = 00
Counter Value
CCRA > 0 Counter cleared by CCRA value
0x3FF
Resume
CCRA
CCRA = 0
Counter overflow
CCRA = 0
Pause
CCRP
Stop
Counter Reset
Time
ETON
ETPAU
ETAPOL
No ETMAF flag
generated on
CCRA overflow
CCRA Int.
Flag ETMAF
CCRP Int.
Flag ETMPF
ETPA O/P Pin
Output does
not change
ETMPF not
generated
Output not affected by
Output Pin set
to Initial Level
Low if ETAOC = 0
Output Toggle
with ETMAF flag
ETMAF flag. Remains High
Now ETAIO [1:0] = 10
Active High Output Select
Here ETAIO [1:0] = 11
Toggle Output Select
until reset by ETON bit
Output inverts
when ETAPOL is high
Output Pin
Reset to initial value
Output controlled
by other pin shared
function
-
ETM CCRA Compare Match Output Mode – ETCCLR=1
Note: 1. With ETCCLR=1, a Comparator A match will clear the counter
2. The ETPA output pin is controlled only by the ETMAF flag
3. The ETPA output pin is reset to its initial state by a ETON bit rising edge
4. The ETMPF flag is not generated when ETCCLR=1
Rev. 1.10
103
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Counter Value
0x3FF
ETCCLR = 1; ETBM [1:0] = 00
CCRA = 0
Counter overflow
CCRA > 0 Counter cleared by CCRA value
Resume
CCRA
Pause
CCRA=0
Stop
Counter Restart
CCRB
Time
ETON
ETPAU
ETBPOL
No ETMAF flag
generated on
CCRA overflow
CCRA Int.
Flag ETMAF
CCRB Int.
Flag ETMBF
ETPB O/P
Pin
Output pin set to
initial Level Low
if ETBOC=0
Output Toggle with
ETMBF flag
Here ETBIO [1:0] = 11
Toggle Output select
Output not affected by
ETMBF flag. Remains High
until reset by ETON bit
Note ETBIO [1:0] = 10
Active High Output select
Output Inverts
when ETBPOL is high
Output Pin
Reset to Initial value
Output controlled by
other pin-shared function
ETM CCRB Compare Match Output Mode – ETCCLR=1
Note: 1. With ETCCLR=1, a Comparator A match will clear the counter
2. The ETPB output pin is controlled only by the ETMBF flag
3. The ETPB output pin is reset to its initial state by a ETON bit rising edge
4. The ETMPF flag is not generated when ETCCLR=1
Rev. 1.10
104
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Timer/Counter Mode
To select this mode, bits ETAM1, ETAM0 and ETBM1, ETBM0 in the ETMC1 and ETMC2
registers should all be set high. The Timer/Counter Mode operates in an identical way to the
Compare Match Output Mode generating the same interrupt flags. The exception is that in the Timer/
Counter Mode the TM output pin is not used. Therefore the above description and Timing Diagrams
for the Compare Match Output Mode can be used to understand its function. As the TM output pin
is not used in this mode, the pin can be used as a normal I/O pin or other pin-shared functions.
PWM Output Mode
To select this mode, the required bit pairs, ETAM1, ETAM0 and ETBM1, ETBM0 in the ETMC1
and ETMC2 registers should be set to 10 respectively. If the ETAIO1, ETAIO0 and ETBIO1,
ETBIO0 bits are also set to 10 respectively, the PWM waveform will be output on the TM output
pin. The PWM function within the TM is useful for applications which require functions such as
motor control, heating control, illumination control etc. By providing a signal of fixed frequency
but of varying duty cycle on the TM output pin, a square wave AC waveform can be generated with
varying equivalent DC RMS values.
As both the period and duty cycle of the PWM waveform can be controlled, the choice of generated
waveform is extremely flexible. In the PWM mode, the ETCCLR bit is used to determine in which
way the PWM period is controlled. With the ETCCLR bit set high, the PWM period can be finely
controlled using the CCRA registers. In this case the CCRB registers are used to set the PWM duty
value (for ETPB output pin). The CCRP bits are not used and ETPA output pin is not used. The
PWM output can only be generated on the ETPB output pin. With the ETCCLR bit cleared to zero,
the PWM period is set using one of the eight values of the three CCRP bits, in multiples of 128.
Now both CCRA and CCRB registers can be used to setup different duty cycle values to provide
dual PWM outputs on their relative ETPA and ETPB pins.
The ETPWM1 and ETPWM0 bits determine the PWM alignment type, which can be either edge
or centre type. In edge alignment, the leading edge of the PWM signals will all be generated
concurrently when the counter is reset to zero. With all power currents switching on at the same
time, this may give rise to problems in higher power applications. In centre alignment the centre
of the PWM active signals will occur sequentially, thus reducing the level of simultaneous power
switching currents.
Interrupt flags, one for each of the CCRA, CCRB and CCRP, will be generated when a compare
match occurs from the Comparator A, Comparator B or Comparator P. The ETAOC and ETBOC bits
in the ETMC1 and ETMC2 register are used to select the required polarity of the PWM waveform
while the two ETAIO1, ETAIO0 and ETBIO1, ETBIO0 bits pairs are used to enable the PWM
output or to force the TM output pin to a fixed high or low level. The ETAPOL and ETBPOL bit are
used to reverse the polarity of the PWM output waveform.
Rev. 1.10
105
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
ETM, PWM Mode, Edge-aligned Mode, ETCCLR=0
CCRP
001b
010b
011b
100b
101b
110b
111b
000b
Period
128
256
384
512
640
768
896
1024
A Duty
CCRA
B Duty
CCRB
If fSYS=12MHz, TM clock source select fSYS/4, CCRP=100b, CCRA=128 and CCRB=256,
The ETPA PWM output frequency=(fSYS/4)/512=fSYS/2048=5.8594kHz, duty=128/512=25%.
The ETPB PWM output frequency=(fSYS/4)/512=fSYS/2048=5.8594kHz, duty=256/512=50%.
If the Duty value defined by CCRA or CCRB register is equal to or greater than the Period value,
then the PWM output duty is 100%.
ETM, PWM Mode, Edge-aligned Mode, ETCCLR=1
CCRA
1
2
3
511
512
1021
1022
1023
Period
1
2
3
511
512
1021
1022
1023
B Duty
CCRB
ETM, PWM Mode, Center-aligned Mode, ETCCLR=0
CCRA
001b
010b
011b
100b
101b
110b
111b
000b
Period
256
512
768
1024
1280
1536
1792
2046
A Duty
(CCRA×2)-1
B Duty
(CCRB×2)-1
ETM, PWM Mode, Center-aligned Mode, ETCCLR=1
CCRA
1
2
3
511
512
1021
1022
1023
Period
2
4
6
1022
1024
2042
2044
2046
B Duty
Rev. 1.10
(CCRB×2)-1
106
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Counter Value
ETCCLR = 0;
ETAM [1:0] = 10, ETBM [1:0] = 10;
ETPWM [1:0] = 00
Counter Cleared by CCRP
CCRP
CCRA
Pause
Resume
Stop
Counter
Restart
CCRB
Time
ETON
ETPAU
ETAPOL
CCRA Int.
Flag ETMAF
CCRB Int.
Flag ETMBF
CCRP Int.
Flag ETMPF
ETPA Pin
(ETAOC=1)
ETPB Pin
Duty Cycle
set by CCRA
Duty Cycle
set by CCRA
Duty Cycle
set by CCRA
Output Inverts
when ETAPOL
is high
(ETBOC=1)
ETPB Pin
(ETBOC=0)
Duty Cycle
set by CCRB
Output controlled by
other pin-shared function
Output Pin
Reset to Initial value
PWM Period set by CCRP
ETM PWM Mode – Edge Aligned
Note: 1. Here ETCCLR=0 therefore CCRP clears the counter and determines the PWM period
2. The internal PWM function continues running even when ETAIO [1:0] (or ETBIO [1:0]) = 00 or 01
3. CCRA controls the ETPA PWM duty and CCRB controls the ETPB PWM duty
Rev. 1.10
107
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
Counter Value
ETCCLR = 1; ETBM [1:0] = 10;
ETPWM [1:0] = 00
Counter Cleared by CCRA
CCRA
Pause
Resume
Counter
Restart
Stop
CCRB
Time
ETON
ETPAU
ETBPOL
CCRA Int.
Flag ETMAF
CCRB Int.
Flag ETMBF
ETPB Pin
(ETBOC=1)
ETPB Pin
(ETBOC=0)
Duty Cycle
set by CCRB
Output controlled by
other pin-shared function
PWM Period set by CCRA
Output Pin
Reset to
Initial value
Output Inverts
when ETBPOL
is high
ETM PWM Mode – Edge Aligned
Note: 1. Here ETCCLR=1 therefore CCRA clears the counter and determines the PWM period
2. The internal PWM function continues running even when ETBIO [1:0] = 00 or 01
3. The CCRA controls the ETPB PWM period and CCRB controls the ETPB PWM duty
4. Here the ETPA pin should not be used as a TM output pin.
Rev. 1.10
108
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
ETCCLR = 0;
ETAM [1:0] = 10, ETBM [1:0] = 10;
ETPWM [1:0] = 11
Counter Value
CCRP
Resume
CCRA
Stop
Counter
Restart
Pause
CCRB
Time
ETON
ETPAU
ETAPOL
CCRA Int.
Flag ETMAF
CCRB Int.
Flag ETMBF
CCRP Int.
Flag ETMPF
ETPA Pin
(ETAOC=1)
ETPB Pin
Duty Cycle set by CCRA
Output Inverts
when ETAPOL
is high
(ETBOC=1)
ETPB Pin
(ETBOC=0)
Duty Cycle set by CCRB
Output controlled by
Other pin-shared function
PWM Period set by CCRP
Output Pin
Reset to Initial value
ETM PWM Mode – Centre Aligned
Note: 1. Here ETCCLR=0 therefore CCRP clears the counter and determines the PWM period
2. ETPWM [1:0] =11 therefore the PWM is centre aligned
3. The internal PWM function continues running even when ETAIO [1:0] (or ETBIO [1:0]) = 00 or 01
4. CCRA controls the ETPA PWM duty and CCRB controls the ETPB PWM duty
5. CCRP will generate an interrupt request when the counter decrements to its zero value
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Flash 8-Bit MCU with LED/LCD Driver
Counter Value
ETCCLR = 1; ETBM [1:0] = 10;
ETPWM [1:0] = 11
CCRA
Resume
Stop
Counter
Restart
Pause
CCRB
Time
ETON
ETPAU
ETBPOL
CCRA Int.
Flag ETMAF
CCRB Int.
Flag ETMBF
CCRP Int.
Flag ETMPF
ETPB Pin
(ETBOC=1)
ETPB Pin
(ETBOC=0)
Output controlled
Output Inverts
by other pin-shared
when ETBPOL is high
function
Output Pin
Reset to Initial value
Duty Cycle set by CCRB
PWM Period set by CCRA
ETM PWM Mode – Centre Aligned
Note: 1. Here ETCCLR =1 therefore CCRA clears the counter and determines the PWM period
2. ETPWM [1:0] =11 therefore the PWM is centre aligned
3. The internal PWM function continues running even when ETBIO [1:0] = 00 or 01
4. CCRA controls the ETPB PWM period and CCRB controls the ETPB PWM duty
5. CCRP will generate an interrupt request when the counter decrements to its zero value
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Flash 8-Bit MCU with LED/LCD Driver
Single Pulse Output Mode
To select this mode, the required bit pairs, ETAM1, ETAM0 and ETBM1, ETBM0 should be set to
10 respectively and also the corresponding ETAIO1, ETAIO0 and ETBIO1, ETBIO0 bits should be
set to 11 respectively. The Single Pulse Output Mode, as the name suggests, will generate a single
shot pulse on the TM output pin.
The trigger for the pulse ETPA output leading edge is a low to high transition of the ETON
bit, which can be implemented using the application program. The trigger for the pulse ETPB
output leading edge is a compare match from Comparator B, which can be implemented using
the application program. However in the Single Pulse Mode, the ETON bit can also be made to
automatically change from low to high using the external ETCK pin, which will in turn initiate the
Single Pulse output of ETPA. When the ETON bit transitions to a high level, the counter will start
running and the pulse leading edge of ETPA will be generated. The ETON bit should remain high
when the pulse is in its active state. The generated pulse trailing edge of ETPA and ETPB will be
generated when the ETON 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 ETON bit and thus
generate the Single Pulse output trailing edge of ETPA and ETPB. In this way the CCRA value can
be used to control the pulse width of ETPA. The (CCRA-CCRB) value can be used to control the
pulse width of ETPB. A compare match from Comparator A and Comparator B will also generate
TM interrupts. The counter can only be reset back to zero when the ETON bit changes from low to
high when the counter restarts. In the Single Pulse Mode CCRP is not used. The ETCCLR bit is also
not used.
Counter Value
CCRA
CCRB
0
S/W Command
SET“ETON”
or
ETCK Pin
Transition
Time
CCRA
Leading Edge
CCRA
Trailing Edge
ETON bit
0à1
ETON bit
1à0
S/W Command
CLR“ETON”
or
CCRA Compare
Match
ETPA Output Pin
Pulse Width = CCRA Value
ETPB Output Pin
Pulse Width = (CCRA-CCRB) Value
CCRB Compare
Match
ETON = 1
ETON bit
1à0
CCRB
Leading Edge
CCRB
Trailing Edge
S/W Command
CLR“ETON”
or
CCRA Compare
Match
Single Pulse Generation
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Flash 8-Bit MCU with LED/LCD Driver
Counter Value
ETAM [1:0] = 10, ETBM [1:0] = 10;
ETAIO [1:0] = 11, ETBIO [1:0] = 11
Counter stopped
by CCRA
CCRA
Pause
Counter Stops
by software
Resume
CCRB
Counter Reset
when ETON
returns high
Time
ETON
Software
Trigger
Cleared by
CCRA match
Auto. set by
ETCK pin
ETCK pin
Software
Trigger
Software
Trigger
Software
Trigger
Software
Clear
ETCK pin
Trigger
ETPAU
ETAPOL
ETBPOL
CCRB Int.
Flag ETMBF
CCRA Int.
Flag ETMAF
ETPA Pin
(ETAOC=1)
ETPA Pin
Pulse Width
set by CCRA
(ETAOC=0)
Output Inverts
when ETAPOL=1
ETPB Pin
(ETBOC=1)
ETPB Pin
(ETBOC=0)
Pulse Width set
by (CCRA-CCRB)
Output Inverts
when ETBPOL=1
ETM – Single Pulse Mode
Note: 1. Counter stopped by CCRA
2. CCRP is not used
3. The pulse triggered by the ETCK pin or by setting the ETON bit high
4. A ETCK pin active edge will automatically set the ETON bit high.
5. In the Single Pulse Mode, ETAIO [1:0] and ETBIO [1:0] must be set to "11" and can not be changed
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Flash 8-Bit MCU with LED/LCD Driver
Capture Input Mode
To select this mode bits ETAM1, ETAM0 and ETBM1, ETBM0 in the ETMC1 and ETMC2
registers 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 ETPIA and ETPIB pins, whose active edge
can be either a rising edge, a falling edge or both rising and falling edges; the active edge transition
type is selected using the ETAIO1, ETAIO0 and ETBIO1, ETBIO0 bits in the ETMC1 and ETMC2
registers. The counter is started when the ETON bit changes from low to high which is initiated using
the application program.
When the required edge transition appears on the ETPIA and ETPIB pins the present value in the
counter will be latched into the CCRA and CCRB registers and a TM interrupt generated. Irrespective
of what events occur on the ETPIA and ETPIB pins the counter will continue to free run until the
ETON bit changes from high to low. When a CCRP compare match occurs the counter will reset
back to zero; in this way the CCRP value can be used to control the maximum counter value. When a
CCRP compare match occurs from Comparator P, a TM interrupt will also be generated. Counting the
number of overflow interrupt signals from the CCRP can be a useful method in measuring long pulse
widths. The ETAIO1, ETAIO0 and ETBIO1, ETBIO0 bits can select the active trigger edge on the
ETPIA and ETPIB pins to be a rising edge, falling edge or both edge types. If the ETAIO1, ETAIO0
and ETBIO1, ETBIO0 bits are both set high, then no capture operation will take place irrespective of
what happens on the ETPIA and ETPIB pins, however it must be noted that the counter will continue
to run.
Note that the ETCCLR, ETAOC, ETBOC, ETAPOL and ETBPOL bits are not used in this mode.
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Flash 8-Bit MCU with LED/LCD Driver
Counter Value
ETAM [1:0] = 01
Counter cleared
by CCRP
Counter Counter
Reset
Stop
CCRP
YY
Pause
Resume
XX
Time
ETON
ETPAU
ETM Capture
pin ETPIA
Active
edge
Active
edge
Active edge
CCRA Int.
Flag ETMAF
CCRP Int.
Flag ETMPF
CCRA
Value
ETAIO [1:0]
Value
XX
00 – Rising edge
YY
XX
01 – Falling edge 10 – Both edges
YY
11 – Disable Capture
ETM CCRA Capture Input Mode
Note: 1. ETAM [1:0] = 01 and active edge set by the ETAIO [1:0] bits
2. The TM Capture input pin active edge transfers the counter value to CCRA
3. ETCCLR bit not used
4. No output function – ETAOC and ETAPOL bits not used
5. CCRP determines the counter value and the counter has a maximum count value when CCRP is equal to
zero
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Flash 8-Bit MCU with LED/LCD Driver
Counter Value
ETBM [1:0] = 01
Counter cleared
by CCRP
Counter Counter
Stop
Reset
CCRP
YY
Pause
Resume
XX
Time
ETON
ETPAU
TM Capture
pin ETPIB
Active
edge
Active
edge
Active edge
CCRB Int.
Flag ETMBF
CCRP Int.
Flag ETMPF
CCRB
Value
ETBIO [1:0]
Value
XX
00 – Rising edge
YY
01 – Falling edge
XX
10 – Both edges
YY
11 – Disable Capture
ETM CCRB Capture Input Mode
Note: 1. ETBM [1:0] = 01 and active edge set by the ETBIO [1:0] bits
2. The TM Capture input pin active edge transfers the counter value to CCRB
3. ETCCLR bit not used
4. No output function -- ETBOC and ETBPOL bits not used
5. CCRP determines the counter value and the counter has a maximum count value when CCRP is equal to
zero.
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Flash 8-Bit MCU with LED/LCD Driver
Software LCD Driver
The device has the capability of driving external LCD panels. The segment pins for LCD
driving, SEG0~SEG23, are pin shared with certain pins on the PA~PD ports. The LCD signals,
SEG0~SEG23, are generated using the application program.
LCD Operation
An external LCD panel can be driven using this device by configuring the specific pins as segment
or common pins. The LCD driver function is controlled using the SLCDC register which in addition
to controlling the overall on/off function also controls the bias current selection function. This
enables the LCD SEG driver to generate the necessary voltage levels for LCD 1/3 bias operation.
The SLCDEN bit in the SLCDC register is the overall master control for the software LCD driver.
However, this bit is used to generate the LCD bias voltage levels and enable the specific SEG pins
used for LCD driving together with the corresponding pin shared control bits. Note that the I/O Port
ontrol register does not need to first setup the pins as outputs to enable the LCD driver operation.
When the SLCDEN bit is set to 1 and the SEGn pin is configured to output a SEG_H level by the
relevant pin shared control bits, the specific SEGn pin will output a 2/3*VDD voltage. However, the
specific SEGn pin will output a 1/3*VDD voltage if the corresponding pin shared control bits set this
SEGn pin to output a SEG_L level and the SLCDEN bit is high. Refer to the "Pin-shared Functions"
section for detailed pin-shared control definitions.
SLCDEN
Pin shared Control Bits
Pin Function
Pin Voltage Level
1
10
SEG_L
1/3*VDD
1
11
SEG_H
2/3*VDD
SEG Pin Output Control
SLCD Bias and Pin Control
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Flash 8-Bit MCU with LED/LCD Driver
LCD Bias Control
The software LCD driver enables a range of selections to be provided to suit the requirement of the
LCD panel which is being used. The bias current choice is implemented using the ISEL1 and ISEL0
bits in the SLCDC register.
SLCDC Register
Bit
7
6
5
4
3
2
1
0
Name
—
ISEL1
ISEL0
SLCDEN
—
—
—
—
R/W
—
R/W
R/W
R/W
—
—
—
—
POR
—
0
0
0
—
—
—
—
Bit 7
Unimplemented, read as "0"
Bit 6~5 ISEL1~ISEL0: SLCD Bias Current Select
00: 8μA
01: 16μA
10: 50μA
11: 100μA
Bit 4 SLCDEN: SLCD function Enable control
0: disable
1: enable
Bit 3~0 Unimplemented, read as "0"
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.
This device provides an internal pull-high resistor which is connected on the SDA or SCL line
respectively if the corresponding pull-high function control is enabled. 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
operates 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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Flash 8-Bit MCU with LED/LCD Driver
The I2CDBNC1 and I2CDBNC0 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 debounce
fSYS > 2MHz
fSYS > 5MHz
2 system clock debounce
fSYS > 4MHz
fSYS > 10MHz
fSYS > 8MHz
fSYS > 20MHz
4 system clock debounce
I C Minimum fSYS Frequency
2
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  †   † I2C Block Diagram
I2C Registers
There are three control registers associated with the I2C bus, IICC0, IICC1 and I2CTOC, one
data register, IICD, and one address register, IICA. The IICD register, which is shown in the I2C
block diagram, 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
IICD register. After the data is received from the I2C bus, the microcontroller can read it from the
IICD register. Any transmission or reception of data from the I2C bus must be made via the IICD
register. The IICA register is used to store the I2C slave address.
Name
Bit
7
6
5
4
IICC0
—
—
—
—
IICC1
IICHCF
IICHAAS
IICHBB
IICHTX
IICTXAK
IICSRW
IICD
D7
D6
D5
D4
D3
D2
IICA6
IICA5
IICA4
IICA3
IICA2
IICA
I2CTOC
3
2
I2CDBNC1 I2CDBNC0
I2CTOEN I2CTOF I2CTOS5 I2CTOS4 I2CTOS3
IICA1
I2CTOS2
1
0
IICEN
—
IICAMWU IICRXAK
D1
D0
IICA0
D0
I2CTOS1 I2CTOS0
I2C Register List
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Flash 8-Bit MCU with LED/LCD Driver
IICC0 Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
I2CDBNC1
I2CDBNC0
IICEN
—
R/W
—
—
—
—
R/W
R/W
R/W
—
POR
—
—
—
—
0
0
0
—
Bit 7~4 unimplemented, read as "0"
Bit 3~2 I2CDBNC1~I2CDBNC0: I2C Debounce Time Selection
00: No debounce
01: 2 system clock debounce
1x: 4 system clock debounce
Bit 1IICEN: I2C interface enable control
0: Disable
1: Enable
Bit 0
unimplemented, read as "0"
IICC1 Register
Bit
7
6
5
4
3
2
Name
IICHCF
IICHAAS
IICHBB
IICHTX
IICTXAK
IICSRW
1
0
R/W
R
R
R
R/W
R/W
R
R/W
R
POR
1
0
0
0
0
0
0
1
IICAMWU IICRXAK
Bit 7IICHCF: I C Bus data transfer completion flag
0: Data is being transferred
1: Completion of an 8-bit data transfer
The IICHCF 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 6IICHAAS: I2C Bus address match flag
0: Not address match
1: Address match
The IICHAAS 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 5IICHBB: I2C Bus busy flag
0: I2C Bus is not busy
1: I2C Bus is busy
The IICHBB 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 4IICHTX: Select I2C slave device is transmitter or receiver
0: Slave device is the receiver
1: Slave device is the transmitter
Bit 3IICTXAK: I2C Bus transmit acknowledge flag
0: Slave send acknowledge flag
1: Slave do not send acknowledge flag
The IICTXAK 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 IICTXAK bit to "0" before further data is
received.
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Flash 8-Bit MCU with LED/LCD Driver
Bit 2IICSRW: I2C Slave Read/Write flag
0: Slave device should be in receive mode
1: Slave device should be in transmit mode
The IICSRW flag is the I2C 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 IICHAAS flag is set
high, the slave device will check the IICSRW flag to determine whether it should be
in transmit mode or receive mode. If the IICSRW flag is high, the master is requesting
to read data from the bus, so the slave device should be in transmit mode. When the
IICSRW 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 1IICAMWU: 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 IICAMWU 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.
Bit 0IICRXAK: I2C Bus Receive acknowledge flag
0: Slave receive acknowledge flag
1: Slave does not receive acknowledge flag
The IICRXAK flag is the receiver acknowledge flag. When the IICRXAK 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 IICRXAK flag to determine if the master receiver wishes to receive
the next byte. The slave transmitter will therefore continue sending out data until the
IICRXAK 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.
IICD 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
Bit 7~0
I2C Bus data bit 7~bit 0
The IICD register is used to store the data being transmitted and received. Before the
device writes data to the I2C bus, the actual data to be transmitted must be placed in
the IICD register. After the data is received from the I2C bus, the device can read it
from the IICD register. Any transmission or reception of data from the I2C bus must be
made via the IICD register.
IICA Register
Rev. 1.10
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
0
0
0
0
0
0
0
0
Bit 7~1
IICA6~IICA0: I2C Slave address bit 6~bit 0
The IICA register is the location where the 7-bit slave address of the I2C slave device
is stored. When a master device, which is connected to the I2C bus, sends out an
address, which matches the slave address in the IICA register, the slave device will be
selected.
Bit 0
Undefined bit
This bit can be read or written by user software program.
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Flash 8-Bit MCU with LED/LCD Driver
I2CTOC Register
Bit
7
6
Name
I2CTOEN
I2CTOF
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
I2CTOS5 I2CTOS4 I2CTOS3 I2CTOS2 I2CTOS1 I2CTOS0
Bit 7I2CTOEN: I C interface Time-out control
0: Disable
1: Enable
2
Bit 6I2CTOF: I2C interface Time-out flag
0: No time-out occurred
1: Time-out occurred
The I2CTOF flag is set by the time-out circuitry when the time-out event occurs and
cleared by software program.
Bit 5~0 I2CDBNC1~I2CDBNC0: I2C interface Time-out period selection
I2C interface Time-out period =
( I 2CTOS [5 : 0] + 1) x32
f SUB
The I2C Time-out circuitry is driven by the (fSUB/32) clock and the tinme-out period is
calculated using the above formula.
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 IICHAAS bit in the
IICC1 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 IICHAAS bit to determine whether the
interrupt source originates from an address match or from the completion of an 8-bit data transfer.
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 IICSRW 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
Configure the corresponding I/O pins as the I2C interface pins, SDA and SCL, using the pinshared control bits and set the IICEN bit high to enable the I2C interface function.
• Step 2
Write the slave address of the device to the I2C bus address register IICA.
• Step 3
Set the corresponding I2C interrupt enable bit in the interrupt control register to enable the I2C
interrupt.
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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 IICHBB 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 IICSRW bit of the IICC1 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 IICHAAS when the addresses match.
As an I2C bus interrupt can come from three sources, when the program enters the interrupt
subroutine, the I2CTOF bit should first be checked to see whether the I2C interface time-out event
occurs. If there is no I2C time-out event occurs, then the IICHAAS bit should be examined to see
whether the interrupt source has come from a matching slave address or from the completion of a
data byte transfer. When a slave address is matched, the devices must be placed in either the transmit
mode and then write data to the IICD register, or in the receive mode where it must implement a
dummy read from the IICD register to release the SCL line.
I2C Read/Write Signal
The IICSRW bit in the IICC1 register defines whether the slave 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 IICSRW 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 IICSRW 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 Slave Address Acknowledge Signal
After the master has transmitted a calling address, any slave device on the I2C 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 IICHAAS flag is high, the addresses have matched and the slave device
must check the IICSRW flag to determine if it is to be a transmitter or a receiver. If the IICSRW flag
is high, the slave device should be setup to be a transmitter so the IICHTX bit in the IICC1 register
should be set to "1". If the IICSRW flag is low, then the microcontroller slave device should be setup
as a receiver and the IICHTX bit in the IICC1 register should be set to "0".
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I2C Data/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 IICD
register. If setup as a transmitter, the slave device must first write the data to be transmitted into the
IICD register. If setup as a receiver, the slave device must read the transmitted data from the IICD
register.
When the slave receiver receives the data byte, it must generate an acknowledge bit, known
as IICTXAK, on the 9th clock. The slave device, which is setup as a transmitter will check the
IICRXAK bit in the IICC1 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 IICD register, or in the receive mode where it must implememt a
dummy read from the IICD register to release the SCL line.
I2C Communication Timing Diagram
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       
    I2C Bus ISR Flow Chart
I2C Timing-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 I2CTOC register, then a time-out condition will occur. The time-out function will
stop when an I2C "STOP" condition occurs.
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Flash 8-Bit MCU with LED/LCD Driver
S C L
S ta rt
IIC S R W
S la v e A d d r e s s
0
1
S D A
1
1
0
1
0
1
A C K
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 Diagram
When an I2C time-out counter overflow occurs, the counter will stop and the I2CTOEN bit will
be cleared to zero and the I2CTOF 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 Tiome-out
IICD, IICA, IICC0
No change
IICC1
Reset to POR condition
I2C Registers after Time-out
The I2CTOF flag can be cleared by the application program. There are 64 time-out period selections
which can be selected using the I2CTOS bits in the I2CTOC 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.
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UART Interface
The 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
MSB
Transmitter Shift Register
………………………… LSB
TX Pin
CLK
RX Pin
Baud Rate
Generator
TXR Register
MSB
Receiver Shift Register
…………………………
LSB
CLK
RXR Register
Buffer
MCU Data Bus
UART Data Transfer Scheme
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UART External Pins
To communicate with an external serial interface, the internal UART has two external pins known
as TX and RX. The TX pin is the UART transmitter pin, which can be used as a general purpose I/
O or other pin-shared functional pin if the pin is not configured as a UART transmitter pin, which
depends upon the corresponding pin-shared control configuration. Similarly, the RX pin is the UART
receiver pin, which can also be used as a general purpose I/O pin or other pin-shared functional
pin, if the pin is not configured as a receiver pin, which also depends upon the corresponding pinshared control configuration. According to the pin-shared control configuration, if the TX or RX
pin is selected as an UART interface pin, the internal pull-high resistor on the TX or RX pin will be
disabled automatically.
UART Data Transfer Scheme
The block 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 RXR
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 register.
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
USR
PERR
NF
FERR
OERR
RIDLE
RXIF
TIDLE
TXIF
UCR1
UARTEN
BNO
PREN
PRT
STOPS
TXBRK
RX8
TX8
UCR2
TXEN
RXEN
BRGH
ADDEN
WAKE
RIE
TIIE
TEIE
TXR_RXR
TXRX7
TXRX6
TXRX5
TXRX4
TXRX3
TXRX2
TXRX1
TXRX0
BRG
BRG7
BRG6
BRG5
BRG4
BRG3
BRG2
BRG1
BRG0
UART Register List
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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.
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.
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Flash 8-Bit MCU with LED/LCD Driver
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.
UCR1 Register
The UCR1 register together with the UCR2 register are the two 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
Bit 7UARTEN: UART function enable control
0: disable UART. TX and RX pins can be I/O or other pin-shared functions
1: enable UART. TX and RX pins should be configured as UART pins
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 can be set as I/O or other pinshared functions. When the bit is equal to "1", the UART will be enabled and the TX
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Flash 8-Bit MCU with LED/LCD Driver
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.
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 operates 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 transfers 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 transfers are in 8-bit or 9-bit format.
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Flash 8-Bit MCU with LED/LCD Driver
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 bit named TXEN 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 can be used as an I/O or
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 can be
used as an I/O or other pin-shared functional pin.
Bit 6RXEN: UART Receiver enable control
0: UART Receiver is disabled
1: UART Receiver is enabled
The bit named RXEN 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 can be used as an I/O or
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 can be used as
an I/O or other pin-shared functional pin.
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.
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Flash 8-Bit MCU with LED/LCD Driver
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 IDLE 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 IDLE or SLEEP 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.
Baud 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 timer, 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)
f SYS
[64( N + 1)]
f SYS
[16( N + 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.
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• 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.
From the above table the desired baud rate BR =
f SYS
f SYS
[64( N + 1)]
Re-arranging this equation gives N = ( BR × 64) − 1
Giving a value for N =
4000000
− 1 = 12.0208
(4800 × 64)
To obtain the closest value, a decimal value of 12 should be placed into the BRG register. This gives
an actual or calculated baud rate value of BR=
Therefore the error is equal to
4808 − 4800
4800
4000000
= 4808
[64(12 + 1)]
= 0.16%
The following tables show the actual values of baud rate and error values for the two values of
BRGH.
Baud Rates for BRGH=0
Baud
Rate
K/BPS
BRGn
Kbaud
Error(%)
BRGn
Kbaud
Error(%)
BRGn
Kbaud
0.3
207
0.300
0.16
185
0.300
0.00
—
—
—
1.2
51
1.202
0.16
46
1.190
-0.83
92
1.203
0.23
-0.83
fSYS=4MHz
fSYS=3.579545MHz
fSYS=7.159MHz
Error(%)
2.4
25
2.404
0.16
22
2.432
1.32
46
2.380
4.8
12
4.808
0.16
11
4.661
-2.90
22
4.863
1.32
9.6
6
8.929
-6.99
5
9.321
-2.90
11
9.332
-2.90
19.2
2
20.833
8.51
2
18.643
-2.90
5
18.643
-2.90
38.4
—
—
—
—
—
—
2
32.286
-2.90
57.6
0
62.500
8.51
0
55.930
-2.90
1
55.930
-2.90
115.2
—
—
—
—
—
—
0
111.859
-2.90
Baud Rates and Error Values for BRGH=0
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Baud Rates for BRGH=1
Baud
Rate
K/BPS
BRGn
Kbaud
Error(%)
BRGn
Kbaud
Error(%)
BRGn
Kbaud
0.3
—
—
—
—
—
—
—
—
—
1.2
207
1.202
0.16
185
1.203
0.23
—
—
—
2.4
103
2.404
0.16
92
2.406
0.23
185
2.406
0.23
4.8
51
4.808
0.16
46
4.76
-0.83
92
4.811
0.23
-0.83
fSYS=4MHz
fSYS=3.579545MHz
fSYS=7.159MHz
Error(%)
9.6
25
9.615
0.16
22
9.727
1.32
46
9.520
19.2
12
19.231
0.16
11
18.643
-2.90
22
18.643
1.32
38.4
6
35.714
-6.99
5
37.286
-2.90
11
37.286
-2.90
57.6
0
62.500
8.51
3
55.930
-2.90
7
55.930
-2.90
115.2
1
125
8.51
1
111.86
-2.90
3
111.86
-2.90
250
0
250
0
—
—
—
—
—
—
Baud Rates and Error Values for BRGH=0
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/Disable 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 can 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.
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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
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 BNOn 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 can then return to the I/
O or other pin-shared function.
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Transmitting Data
When the UARTn is transmitting data, the data is shifted on the TXn pin from the shift register, with
the least significant bit LSB first. In the transmit mode, the TXRn 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 TX8n bit in the UCR1n 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.
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:
• A USR register access
• 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:
• A USR register access
• 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.
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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 third byte can continue to be
received. Note that the application program must ensure that the data is read from RXR before the
third byte has been completely shifted in, otherwise the third 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
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,
and then the error flags can be set.
The RXIF bit can be cleared using the following software sequence:
• A USR register access
• A RXR register read execution
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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.
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 third byte can continue to be received. Before the third 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.
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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, only the first stop bit is detected and it must be high. If the
first stop bit is low, 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.
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 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.
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UCR2 Register
USR Register
Transmitter Empty
Flag TXIF
TEIE
0
1
Transmitter Idle
Flag TIDLE
TIIE
0
1
RIE
0
1
Receiver Overrun
Flag OERR
OR
Receiver Data
Available RXIF
RX Pin
Wake-up
WAKE
ADDEN
UART Interrupt
Request Flag
URF
INTC0
URE
To MCU
interrupt Circuitry
EMI
0
1
0
1
0
1
RX7 if BNO=0
RX8 if BNO=1
UCR2 Register
UART Interrupt Structure
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.
ADDENn
Bit 9 if BNO=1
Bit 8 if BNO=0
UART Interrupt Generated
0
v
1
v
0
x
1
v
0
1
ADDEN Bit Function
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UART Wake-up
When the MCU enters the Power Down Mode and the system clock is stopped, the UART interface
will cease to function since the UART driven clock source is derived from the system clock. If the
MCU enters the Power Down Mode 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 enters the Power Down Mode while receiving data, then the reception of
data will likewise be paused. When the MCU enters the Power Down 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 Power Down Mode, then a falling edge on the RX pin will wake up the MCU from the Power
Down 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 also be set. If these two
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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Interrupts
Interrupts are an important part of any microcontroller system. When an external event or an
internal function such as a Timer Module requires microcontroller attention, their corresponding
interrupt will enforce a temporary suspension of the main program allowing the microcontroller to
direct attention to their respective needs. The device contains several external interrupt and internal
interrupts functions. The external interrupts are generated by the action of the external INT0~INT1
pins, while the internal interrupts are generated by various internal functions such as the TMs, Time
Base and LVD.
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 registers as well as
interrupt flags to indicate the presence of an interrupt request. The naming convention of these
follows a specific pattern. First is listed an abbreviated interrupt type, then the (optional) number of
that interrupt followed by either an "E" for enable/disable bit or "F" for request flag.
Function
Global
INTn Pin
Enable Bit
Request Flag
EMI
—
Notes
—
INTnE
INTnF
n=0~1
Time Base
TBnE
TBnF
n=0~1
Multi-function
MFnE
MFnF
n=0~2
I2C Interface
IICE
IICF
—
UART Interface
URE
URF
—
LVD
LVE
LVF
—
EEPROM
CTM
ETM
TM
DEE
DEF
—
CTMPE
CTMPF
—
CTMAE
CTMAF
—
ETMPE
ETMPF
—
ETMAE
ETMAF
—
ETMBE
ETMBF
—
PTMPE
PTMPF
—
PTMAE
PTMAF
—
Interrupt Register Bit Naming Conventions
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Bit
Name
INTEG
7
6
5
4
3
2
1
0
—
—
—
—
INT1S1
INT1S0
INT0S1
INT0S0
INTC0
—
TB0F
INT1F
INT0F
TB0E
INT1E
INT0E
EMI
INTC1
MF2F
MF1F
MF0F
TB1F
MF2E
MF1E
MF0E
TB1E
INTC2
—
—
URF
IICF
—
—
URE
IICE
MFI0
PTMAF
PTMPF
CTMAF
CTMPF
PTMAE
PTMPE
CTMAE
CTMPE
MFI1
—
ETMBF
ETMAF
ETMPF
—
ETMBE
ETMAE
ETMPE
MFI2
—
—
DEF
LVF
—
—
DEE
LVE
Interrupt Registers List
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
—
—
—
—
0
0
0
0
POR
Bit 7~4 Bit 3~2 Bit 1~0 Unimplemented, read as "0"
INT1S1, INT1S0: interrupt edge control for INT1 pin
00: Disable
01: Rising edge
10: Falling edge
11: Rising and falling edges
INT0S1, INT0S0: interrupt edge control for INT0 pin
00: Disable
01: Rising edge
10: Falling edge
11: Rising and falling edge
INTC0 Register
Bit
7
6
5
4
3
2
1
0
Name
—
TB0F
INT1F
INT0F
TB0E
INT1E
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 6 TB0F: Time Base 0 interrupt request flag
0: No request
1: Interrupt request
Bit 5 INT1F: INT1 interrupt request flag
0: No request
1: Interrupt request
Bit 4 INT0F: INT0 interrupt request flag
0: No request
1: Interrupt request
Bit 3 TB0E: Time Base 0 interrupt control
0: Disable
1: Enable
Bit 2 INT1E: INT1 interrupt control
0: Disable
1: Enable
Bit 1 INT0E: INT0 interrupt control
0: Disable
1: Enable
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Bit 0 EMI: Global interrupt control
0: Disable
1: Enable
INTC1 Register
Bit
7
6
5
4
3
2
1
0
Name
MF2F
MF1F
MF0F
TB1F
MF2E
MF1E
MF0E
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 7 MF2F: Multi-function interrupt 2 request flag
0: No request
1: Interrupt request
Bit 6 MF1F: Multi-function interrupt 1 request flag
0: No request
1: Interrupt request
Bit 5 MF0F: Multi-function interrupt 0 request flag
0: No request
1: Interrupt request
Bit 4 TB1F: Time Base 1 interrupt request flag
0: No request
1: Interrupt request
Bit 3 MF2E: Multi-function interrupt 2 control
0: Disable
1: Enable
Bit 2 MF1E: Multi-function interrupt 1 control
0: Disable
1: Enable
Bit 1 MF0E: Multi-function interrupt 0 control
0: Disable
1: Enable
Bit 0 TB1E: Time Base 1 interrupt control
0: Disable
1: Enable
INTC2 Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
URF
IICF
—
—
URE
IICE
R/W
—
—
R/W
R/W
—
—
R/W
R/W
POR
—
—
0
0
—
—
0
0
Bit 7~6 unimplemented, read as "0"
Bit 5 URF: UART interface interrupt request flag
0: No request
1: Interrupt request
Bit 4 IICF: I2C interface interrupt request flag
0: No request
1: Interrupt request
Bit 3~2 unimplemented, read as "0"
Bit 1 URE: UART interface interrupt control
0: Disable
1: Enable
Bit 0 IICE: I2C interface interrupt control
0: Disable
1: Enable
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MFI0 Register
Bit
7
6
5
4
3
2
1
0
Name
PTMAF
PTMPF
CTMAF
CTMPF
PTMAE
PTMPE
CTMAE
CTMPE
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 PTMAF: PTM Comparator A match interrupt request flag
0: No request
1: Interrupt request
Bit 6 PTMPF: PTM Comparator P match interrupt request flag
0: No request
1: Interrupt request
Bit 5 CTMAF: CTM Comparator A match interrupt request flag
0: No request
1: Interrupt request
Bit 4 CTMPF: CTM Comparator P match interrupt request flag
0: No request
1: Interrupt request
Bit 3 PTMAE: PTM Comparator A match interrupt control
0: Disable
1: Enable
Bit 2 PTMPE: PTM Comparator P match interrupt control
0: Disable
1: Enable
Bit 1 CTMAE: CTM Comparator A match interrupt control
0: Disable
1: Enable
Bit 0 CTMPE: CTM Comparator P match interrupt control
0: Disable
1: Enable
MFI1 Register
Bit
7
6
5
4
3
2
1
0
Name
—
ETMBF
ETMAF
ETMPF
—
ETMBE
ETMAE
ETMPE
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 6 ETMBF: ETM Comparator B match interrupt request flag
0: No request
1: Interrupt request
Bit 5 ETMAF: ETM Comparator A match interrupt request flag
0: No request
1: Interrupt request
Bit 4 ETMPF: ETM Comparator P match interrupt request flag
0: No request
1: Interrupt request
Bit 3 unimplemented, read as "0"
Bit 2 ETMBE: ETM Comparator B match interrupt control
0: Disable
1: Enable
Bit 1 ETMAE: ETM Comparator A match interrupt control
0: Disable
1: Enable
Bit 0 ETMPE: ETM Comparator P match interrupt control
0: Disable
1: Enable
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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 5 DEF: Data EEPROM interrupt request flag
0: No request
1: Interrupt request
Bit 4 LVF: LVD interrupt request flag
0: No request
1: Interrupt request
Bit 3~2 Unimplemented, read as "0"
Bit 1 DEE: Data EEPROM Interrupt Control
0: Disable
1: Enable
Bit 0 LVE: LVD Interrupt Control
0: Disable
1: Enable
Interrupt Operation
When the conditions for an interrupt event occur, such as a TM Comparator P, Comparator A or
Comparator B match etc, the relevant interrupt request flag will be set. Whether the request flag
actually generates a program jump to the relevant interrupt vector is determined by the condition of
the interrupt enable bit. If the enable bit is set high then the program will jump to its relevant vector;
if the enable bit is zero then although the interrupt request flag is set an actual interrupt will not be
generated and the program will not jump to the relevant interrupt vector. The global interrupt enable
bit, if cleared to zero, will disable all interrupts.
When an interrupt is generated, the Program Counter, which stores the address of the next instruction
to be executed, will be transferred onto the stack. The Program Counter will then be loaded with a
new address which will be the value of the corresponding interrupt vector. The microcontroller will
then fetch its next instruction from this interrupt vector. The instruction at this vector will usually
be a "JMP" which will jump to another section of program which is known as the interrupt service
routine. Here is located the code to control the appropriate interrupt. The interrupt service routine
must be terminated with a "RETI" , which retrieves the original Program Counter address from
the stack and allows the microcontroller to continue with normal execution at the point where the
interrupt occurred.
The various interrupt enable bits, together with their associated request flags, are shown in the
accompanying diagrams with their order of priority. Some interrupt sources have their own
individual vector while others share the same multi-function interrupt vector. Once an interrupt
subroutine is serviced, all the other interrupts will be blocked, as the global interrupt enable bit,
EMI bit will be cleared automatically. This will prevent any further interrupt nesting from occurring.
However, if other interrupt requests occur during this interval, although the interrupt will not be
immediately serviced, the request flag will still be recorded.
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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.
EMI auto disabled in ISR
Legend
xxF
Request Flag, no auto reset in ISR
xxF
Request Flag, auto reset in ISR
xxE
Enable Bits
PTM P
PTMPF
PTMPE
PTM A
PTMAF
PTMAE
CTM P
CTMPF
CTMPE
CTM A
CTMAF
CTMAE
ETM P
ETMPF
ETMPE
ETM A
ETMAF
ETMAE
ETM B
ETMBF
ETMBE
EEPROM
DEF
DEE
LVD
LVF
LVE
Interrupts contained within
Multi-Function Interrupts
Interrupt
Name
INT0 Pin
Request
Flags
INT0F
Enable
Bits
INT0E
Master
Enable
EMI
Vector
INT1 Pin
INT1F
INT1E
EMI
08H
Time Base 0
TB0F
TB0E
EMI
0CH
Time Base 1
TB1F
TB1E
EMI
10H
M. Funct. 0
MF0F
MF0E
EMI
14H
M. Funct. 1
MF1F
MF1E
EMI
18H
M. Funct. 2
MF2F
MF2E
EMI
1CH
I2C Interface
IICF
IICE
EMI
20H
UART interface
URF
URE
EMI
24H
04H
Priority
High
Low
Interrupt Structure
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. 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.
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Multi-function Interrupt
Within this 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, EEPROM Interrupt and LVD 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 Multi-Function request flag, will be automatically reset and the EMI bit will be automatically
cleared to disable other interrupts.
However, it must be noted that, although the Multi-function Interrupt flags will be automatically
reset when the interrupt is serviced, the request flags from the original source of the Multi-function
interrupts, namely the TM Interrupts, EEPROM Interrupt and LVD interrupt will not be
automatically reset and must be manually reset by the application program.
Time Base Interrupt
The function of the Time Base Interrupt is to provide regular time signal in the form of an internal
interrupt. It is controlled by the overflow signal from its internal timer. When this happens its
interrupt request flag, TBnF, will be set. To allow the program to branch to its respective interrupt
vector addresses, the global interrupt enable bit, EMI and Time Base enable bit, TBnE, must first be
set. When the interrupt is enabled, the stack is not full and the Time Base overflows, a subroutine
call to its respective vector location will take place. When the interrupt is serviced, the interrupt
request flag, TBnF, 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. Its
clock source, fTB, originates from the internal clock source fSUB or fSYS/4. And then 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 which in turn
controls the Time Base interrupt period is selected using a bit in the TBC register.
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TBC 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 7 TBON: Time Base 0 and Time Base 1 Enable/Disable
0: Disable
1: Enable
Bit 6 TBCK: TB Clock fTB Select
0: fSUB
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 3 LXTLP: LXT Low Power Control
0: Disable (LXT quick start-up)
1: Enable (LXT low power start-up)
Bit 2~0TB02~TB00: Time Base 0 Time-out Period
000: 28/fTB
001: 29/fTB
010: 210/fTB
011: 211/fTB
100: 212/fTB
101: 213/fTB
110: 214/fTB
111: 215/fTB
      Time Base Interrupt
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I2C Interrupt
An I2C Interrupt request will take place when the I2C Interrupt request flag, IICF, is set when the
I2C time-out occurs, slave address matches or data byte transfer completes. To allow the program
to branch to its respective interrupt vector address, the global interrupt enable bit, EMI, and the I2C
Interrupt enable bit, IICE, must first be set. When the interrupt is enabled, the stack is not full and
one of the I2C interrupt event occurs, a subroutine call to the respective Interrupt vector, will take
place. When the Interrupt is serviced, the interrupt request flag will be automatically cleared and the
EMI bit will be automatically cleared to disable other interrupts.
UART Interrupt
An UART Interrupt request will take place when the UART Interrupt request flag, URF, is set when
any one of the UART interrupt events occurs, which are described in the "UART Interrupt Structure"
section. To allow the program to branch to its respective interrupt vector address, the global interrupt
enable bit, EMI, and the UART Interrupt enable bit, URE, must first be set. When the interrupt is
enabled, the stack is not full and one of the UART interrupt event occurs, a subroutine call to the
respective Interrupt vector, will take place. When the Interrupt is serviced, the interrupt request
flag will be automatically cleared and the EMI bit will be automatically cleared to disable other
interrupts.
EEPROM Interrupt
The EEPROM interrupt is contained within the Multi-function Interrupt. An EEPROM Interrupt
request will take place when the EEPROM Interrupt request flag, DEF, is set, which occurs when
an EEPROM write operation ends. To allow the program to branch to its respective interrupt vector
address, the global interrupt enable bit, EMI, and the EEPROM Interrupt enable bit, DEE, and Mutifunction interrupt enable bits, must first be set. When the interrupt is enabled, the stack is not full
and an EEPROM write operation ends, a subroutine call to the respective Multi-function Interrupt
vector, will take place.When the EEPROM 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 DEF flag will not be automatically cleared, it has to be cleared by
the application program.
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.
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TM Interrupts
The Compact and Periodic Type TMs have two interrupts each, while the Enhanced Type TM has
three interrupts. All of the TM interrupts are contained within the Multi-function Interrupts. For each
of the Compact and Periodic Type TMs there are two interrupt request flags, xTMPF and xTMAF
(x=C or P), and two enable bits xTMPE and xTMAE (x=C or P). For the Enhanced Type TM there
are three interrupt request flags ETMPF, ETMAF and ETMBF and three enable bits ETMPE,
ETMAE and ETMBE. 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, A or B 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.
Interrupt Wake-up Function
Each of the interrupt functions has the capability of waking up the microcontroller when in the
SLEEP or IDLE Mode. A wake-up is generated when an interrupt request flag changes from low to
high and is independent of whether the interrupt is enabled or not. Therefore, even though the device
is in the SLEEP or IDLE Mode and its system oscillator stopped, situations such as external edge
transitions on the external interrupt 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.
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Programming Considerations
By disabling the relevant interrupt enable bits, a requested interrupt can be prevented from being
serviced, however, once an interrupt request flag is set, it will remain in this condition in the
interrupt register until the corresponding interrupt is serviced or until the request flag is cleared by
the application program.
Where a certain interrupt is contained within a Multi-function interrupt, then when the interrupt
service routine is executed, as only the Multi-function interrupt request flags, MF0F~MF2F, will
be automatically cleared, the individual request flag for the function needs to be cleared by the
application program.
It is recommended that programs do not use the "CALL" instruction within the interrupt service
subroutine. Interrupts often occur in an unpredictable manner or need to be serviced immediately.
If only one stack is left and the interrupt is not well controlled, the original control sequence will be
damaged once a CALL subroutine is executed in the interrupt subroutine.
Every interrupt has the capability of waking up the microcontroller when it is in SLEEP or IDLE
Mode, the wake up being generated when the interrupt request flag changes from low to high. If it is
required to prevent a certain interrupt from waking up the microcontroller then its respective request
flag should be first set high before enter SLEEP or IDLE Mode.
As only the Program Counter is pushed onto the stack, then when the interrupt is serviced, if the
contents of the accumulator, status register or other registers are altered by the interrupt service
program, their contents should be saved to the memory at the beginning of the interrupt service
routine.
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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Low Voltage Detector – LVD
The 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 detemined. 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 5 LVDO: LVD Output Flag
0: No Low Voltage Detected
1: Low Voltage Detected
Bit 4LVDEN: Low Voltage Detector Enable/Disable
0: Disable
1: Enable
Bit 3 Unimplemented, read as "0"
Bit 2~0 VLVD2~VLVD0: Select LVD Voltage
000: 2.0V
001: 2.2V
010: 2.4V
011: 2.7V
100: 3.0V
101: 3.3V
110: 3.6V
111: 4.0V
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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.
When LVD function is enabled, it is recommended to clear LVD flag first, and then enables interrupt
function to avoid mistake action.
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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
4MHz, 8MHz or 12MHz
Application Circuits
VDD
VDD
0.1uF
I/O Pins
TM Pins
VSS
TX/RX pins
OSC
Circuit
OSC
Circuit
Rev. 1.10
SCL/SDA pins
PD1/OSC1
SEG pins
PD0/OSC2
LED pins
PA1/XT1
PA3/XT2
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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 microcontrollers, 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 three 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 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 Operations
The Periodic 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
where 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 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
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
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
1
1
1
1Note
1Note
1Note
1
1
1
1Note
1
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Arithmetic
Increment & Decrement
INCA [m]
INC [m]
DECA [m]
DEC [m]
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
RRA [m]
RR [m]
RRCA [m]
RRC [m]
RLA [m]
RL [m]
RLCA [m]
RLC [m]
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
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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
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
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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Flash 8-Bit MCU with LED/LCD Driver
CALL addr
Description
Operation
Affected flag(s)
Subroutine call
Unconditionally calls a subroutine at the specified address. The Program Counter then
increments by 1 to obtain the address of the next instruction which is then pushed onto the
stack. The specified address is then loaded and the program continues execution from this
new address. As this instruction requires an additional operation, it is a two cycle instruction.
Stack ← Program Counter + 1
Program Counter ← addr
None
CLR [m]
Description
Operation
Affected flag(s)
Clear Data Memory
Each bit of the specified Data Memory is cleared to 0.
[m] ← 00H
None
CLR [m].i
Description
Operation
Affected flag(s)
Clear bit of Data Memory
Bit i of the specified Data Memory is cleared to 0.
[m].i ← 0
None
CLR WDT
Description
Operation
Affected flag(s)
Clear Watchdog Timer
The TO, PDF flags and the WDT are all cleared.
WDT cleared
TO ← 0
PDF ← 0
TO, PDF
CLR WDT1
Description
Operation
Affected flag(s)
Pre-clear Watchdog Timer
The TO, PDF flags and the WDT are all cleared. Note that this instruction works in
conjunction with CLR WDT2 and must be executed alternately with CLR WDT2 to have
effect. Repetitively executing this instruction without alternately executing CLR WDT2 will
have no effect.
WDT cleared
TO ← 0
PDF ← 0
TO, PDF
CLR WDT2
Description
Operation
Affected flag(s)
Pre-clear Watchdog Timer
The TO, PDF flags and the WDT are all cleared. Note that this instruction works in conjunction
with CLR WDT1 and must be executed alternately with CLR WDT1 to have effect.
Repetitively executing this instruction without alternately executing CLR WDT1 will have no
effect.
WDT cleared
TO ← 0
PDF ← 0
TO, PDF
CPL [m]
Description
Operation
Affected flag(s)
Complement Data Memory
Each bit of the specified Data Memory is logically complemented (1′s complement). Bits which
previously contained a 1 are changed to 0 and vice versa.
[m] ← [m]
Z
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CPLA [m]
Description
Operation
Affected flag(s)
Complement Data Memory with result in ACC
Each bit of the specified Data Memory is logically complemented (1′s complement). Bits which
previously contained a 1 are changed to 0 and vice versa. The complemented result is stored in
the Accumulator and the contents of the Data Memory remain unchanged.
ACC ← [m]
Z
DAA [m]
Description
Operation
Affected flag(s)
Decimal-Adjust ACC for addition with result in Data Memory
Convert the contents of the Accumulator value to a BCD (Binary Coded Decimal) value
resulting from the previous addition of two BCD variables. If the low nibble is greater than 9
or if AC flag is set, then a value of 6 will be added to the low nibble. Otherwise the low nibble
remains unchanged. If the high nibble is greater than 9 or if the C flag is set, then a value of 6
will be added to the high nibble. Essentially, the decimal conversion is performed by adding
00H, 06H, 60H or 66H depending on the Accumulator and flag conditions. Only the C flag
may be affected by this instruction which indicates that if the original BCD sum is greater than
100, it allows multiple precision decimal addition.
[m] ← ACC + 00H or
[m] ← ACC + 06H or [m] ← ACC + 60H or
[m] ← ACC + 66H
C
DEC [m]
Description
Operation
Affected flag(s)
Decrement Data Memory
Data in the specified Data Memory is decremented by 1.
[m] ← [m] − 1
Z
DECA [m]
Description
Operation
Affected flag(s)
Decrement Data Memory with result in ACC
Data in the specified Data Memory is decremented by 1. The result is stored in the
Accumulator. The contents of the Data Memory remain unchanged.
ACC ← [m] − 1
Z
HALT
Description
Operation
Affected flag(s)
Enter power down mode
This instruction stops the program execution and turns off the system clock. The contents of the Data Memory and registers are retained. The WDT and prescaler are cleared. The power
down flag PDF is set and the WDT time-out flag TO is cleared.
TO ← 0
PDF ← 1
TO, PDF
INC [m]
Description
Operation
Affected flag(s)
Increment Data Memory
Data in the specified Data Memory is incremented by 1.
[m] ← [m] + 1
Z
INCA [m]
Description
Operation
Affected flag(s)
Increment Data Memory with result in ACC
Data in the specified Data Memory is incremented by 1. The result is stored in the Accumulator.
The contents of the Data Memory remain unchanged.
ACC ← [m] + 1
Z
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JMP addr
Description
Operation
Affected flag(s)
Jump unconditionally
The contents of the Program Counter are replaced with the specified address. Program
execution then continues from this new address. As this requires the insertion of a dummy
instruction while the new address is loaded, it is a two cycle instruction.
Program Counter ← addr
None
MOV A,[m]
Description
Operation
Affected flag(s)
Move Data Memory to ACC
The contents of the specified Data Memory are copied to the Accumulator.
ACC ← [m]
None
MOV A,x
Description
Operation
Affected flag(s)
Move immediate data to ACC
The immediate data specified is loaded into the Accumulator.
ACC ← x
None
MOV [m],A
Description
Operation
Affected flag(s)
Move ACC to Data Memory
The contents of the Accumulator are copied to the specified Data Memory.
[m] ← ACC
None
NOP
Description
Operation
Affected flag(s)
No operation
No operation is performed. Execution continues with the next instruction.
No operation
None
OR A,[m]
Description
Operation
Affected flag(s)
Logical OR Data Memory to ACC
Data in the Accumulator and the specified Data Memory perform a bitwise
logical OR operation. The result is stored in the Accumulator.
ACC ← ACC ″OR″ [m]
Z
OR A,x
Description
Operation
Affected flag(s)
Logical OR immediate data to ACC
Data in the Accumulator and the specified immediate data perform a bitwise logical OR operation. The result is stored in the Accumulator.
ACC ← ACC ″OR″ x
Z
ORM A,[m]
Description
Operation
Affected flag(s)
Logical OR ACC to Data Memory
Data in the specified Data Memory and the Accumulator perform a bitwise logical OR operation. The result is stored in the Data Memory.
[m] ← ACC ″OR″ [m]
Z
RET
Description
Operation
Affected flag(s)
Return from subroutine
The Program Counter is restored from the stack. Program execution continues at the restored
address.
Program Counter ← Stack
None
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RET A,x
Description
Operation
Affected flag(s)
Return from subroutine and load immediate data to ACC
The Program Counter is restored from the stack and the Accumulator loaded with the specified immediate data. Program execution continues at the restored address.
Program Counter ← Stack
ACC ← x
None
RETI
Description
Operation
Affected flag(s)
Return from interrupt
The Program Counter is restored from the stack and the interrupts are re-enabled by setting the
EMI bit. EMI is the master interrupt global enable bit. If an interrupt was pending when the RETI instruction is executed, the pending Interrupt routine will be processed before returning to the main program.
Program Counter ← Stack
EMI ← 1
None
RL [m]
Description
Operation
Affected flag(s)
Rotate Data Memory left
The contents of the specified Data Memory are rotated left by 1 bit with bit 7 rotated into bit 0.
[m].(i+1) ← [m].i; (i=0~6)
[m].0 ← [m].7
None
RLA [m]
Description
Operation
Affected flag(s)
Rotate Data Memory left with result in ACC
The contents of the specified Data Memory are rotated left by 1 bit with bit 7 rotated into bit 0.
The rotated result is stored in the Accumulator and the contents of the Data Memory remain
unchanged.
ACC.(i+1) ← [m].i; (i=0~6)
ACC.0 ← [m].7
None
RLC [m]
Description
Operation
Affected flag(s)
Rotate Data Memory left through Carry
The contents of the specified Data Memory and the carry flag are rotated left by 1 bit. Bit 7
replaces the Carry bit and the original carry flag is rotated into bit 0.
[m].(i+1) ← [m].i; (i=0~6)
[m].0 ← C
C ← [m].7
C
RLCA [m]
Description
Operation
Affected flag(s)
Rotate Data Memory left through Carry with result in ACC
Data in the specified Data Memory and the carry flag are rotated left by 1 bit. Bit 7 replaces the
Carry bit and the original carry flag is rotated into the bit 0. The rotated result is stored in the
Accumulator and the contents of the Data Memory remain unchanged.
ACC.(i+1) ← [m].i; (i=0~6)
ACC.0 ← C
C ← [m].7
C
RR [m]
Description
Operation
Affected flag(s)
Rotate Data Memory right
The contents of the specified Data Memory are rotated right by 1 bit with bit 0 rotated into bit 7.
[m].i ← [m].(i+1); (i=0~6)
[m].7 ← [m].0
None
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Flash 8-Bit MCU with LED/LCD Driver
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
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SDZA [m]
Description
Operation
Affected flag(s)
Skip if decrement Data Memory is zero with result in ACC
The contents of the specified Data Memory are first decremented by 1. If the result is 0, the following instruction is skipped. The result is stored in the Accumulator but the specified Data Memory contents remain unchanged. As this requires the insertion of a dummy
instruction while the next instruction is fetched, it is a two cycle instruction. If the result is not 0,
the program proceeds with the following instruction.
ACC ← [m] − 1
Skip if ACC=0
None
SET [m]
Description
Operation
Affected flag(s)
Set Data Memory
Each bit of the specified Data Memory is set to 1.
[m] ← FFH
None
SET [m].i
Description
Operation
Affected flag(s)
Set bit of Data Memory
Bit i of the specified Data Memory is set to 1.
[m].i ← 1
None
SIZ [m]
Description
Operation
Affected flag(s)
Skip if increment Data Memory is 0
The contents of the specified Data Memory are first incremented by 1. If the result is 0, the
following instruction is skipped. As this requires the insertion of a dummy instruction while the next instruction is fetched, it is a two cycle instruction. If the result is not 0 the program
proceeds with the following instruction.
[m] ← [m] + 1
Skip if [m]=0
None
SIZA [m]
Description
Operation
Affected flag(s)
Skip if increment Data Memory is zero with result in ACC
The contents of the specified Data Memory are first incremented by 1. If the result is 0, the following instruction is skipped. The result is stored in the Accumulator but the specified
Data Memory contents remain unchanged. As this requires the insertion of a dummy
instruction while the next instruction is fetched, it is a two cycle instruction. If the result is not
0 the program proceeds with the following instruction.
ACC ← [m] + 1
Skip if ACC=0
None
SNZ [m].i
Description
Operation
Affected flag(s)
Skip if bit i of Data Memory is not 0
If bit i of the specified Data Memory is not 0, the following instruction is skipped. As this
requires the insertion of a dummy instruction while the next instruction is fetched, it is a two cycle instruction. If the result is 0 the program proceeds with the following instruction.
Skip if [m].i ≠ 0
None
SUB A,[m]
Description
Operation
Affected flag(s)
Subtract Data Memory from ACC
The specified Data Memory is subtracted from the contents of the Accumulator. The result is stored in the Accumulator. Note that if the result of subtraction is negative, the C flag will be cleared to 0, otherwise if the result is positive or zero, the C flag will be set to 1.
ACC ← ACC − [m]
OV, Z, AC, C
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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
167
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
TABRD [m]
Description
Operation
Affected flag(s)
Read table (specific page) to TBLH and Data Memory
The low byte of the program code 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
TABRDL [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
168
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
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
169
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
24-pin SOP (300mil) Outline Dimensions
Symbol
A
Dimensions in inch
Min.
Nom.
Max.
—
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°
170
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
28-pin SOP (300mil) Outline Dimensions
Symbol
Dimensions in inch
Min.
Nom.
Max.
A
—
0.406 BSC
—
B
—
0.295 BSC
—
0.020
C
0.012
—
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
—
7.5 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°
171
January 20, 2014
HT69F240
Flash 8-Bit MCU with LED/LCD Driver
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
172
January 20, 2014