A/D Flash MCU with EEPROM
HT66F0195
Revision: V1.20
Date: September 10, 2020
HT66F0195
A/D Flash MCU with EEPROM
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............................................................................................ 13
A.C. Characteristics............................................................................................ 14
HIRC Electrical Characteristics......................................................................... 15
A/D Converter Electrical Characteristics.......................................................... 15
LVD/LVR Electrical Characteristics................................................................... 16
Internal Bandgap Reference Voltage Electrical Characteristics.................... 16
Comparator Electrical Characteristics............................................................. 16
Software Controlled LCD Driver Electrical Characteristics............................ 17
Power-on Reset Characteristics........................................................................ 17
System Architecture........................................................................................... 18
Clocking and Pipelining...............................................................................................................18
Program Counter.........................................................................................................................19
Stack...........................................................................................................................................20
Arithmetic and Logic Unit – ALU.................................................................................................20
Flash Program Memory...................................................................................... 21
Structure......................................................................................................................................21
Special Vectors...........................................................................................................................21
Look-up Table..............................................................................................................................21
Table Program Example..............................................................................................................22
In Circuit Programming – ICP.....................................................................................................23
On-Chip Debug Support ─ OCDS...............................................................................................24
Data Memory....................................................................................................... 24
Structure......................................................................................................................................24
General Purpose Data Memory..................................................................................................25
Special Purpose Data Memory...................................................................................................25
Special Function Register Description............................................................. 27
Indirect Addressing Registers – IAR0, IAR1...............................................................................27
Memory Pointers – MP0, MP1....................................................................................................27
Bank Pointer – BP.......................................................................................................................28
Accumulator – ACC.....................................................................................................................28
Program Counter Low Register – PCL........................................................................................28
Rev. 1.20
2
September 10, 2020
HT66F0195
A/D Flash MCU with EEPROM
Look-up Table Registers – TBLP, TBHP, TBLH...........................................................................28
Status Register – STATUS..........................................................................................................29
EEPROM Data Memory....................................................................................... 30
EEPROM Data Memory Structure..............................................................................................30
EEPROM Registers....................................................................................................................30
Reading Data from the EEPROM...............................................................................................32
Writing Data to the EEPROM......................................................................................................32
Write Protection...........................................................................................................................32
EEPROM Interrupt......................................................................................................................32
Programming Considerations......................................................................................................33
Oscillators........................................................................................................... 34
Oscillator Overview.....................................................................................................................34
System Clock Configurations......................................................................................................34
External Crystal/Ceramic Oscillator – HXT.................................................................................35
High Speed Internal RC Oscillator – HIRC.................................................................................36
External 32.768kHz Crystal Oscillator – LXT..............................................................................36
Internal 32kHz Oscillator – LIRC.................................................................................................37
Supplementary Oscillators..........................................................................................................37
Operating Modes and System Clocks.............................................................. 38
System Clocks............................................................................................................................38
System Operation Modes............................................................................................................39
Control Registers........................................................................................................................40
Fast Wake-up..............................................................................................................................42
Operating Mode Switching .........................................................................................................43
Standby Current Considerations ................................................................................................47
Wake-up......................................................................................................................................47
Programming Considerations......................................................................................................48
Watchdog Timer.................................................................................................. 49
Watchdog Timer Clock Source....................................................................................................49
Watchdog Timer Control Register...............................................................................................49
Watchdog Timer Operation.........................................................................................................50
Reset and Initialisation....................................................................................... 51
Reset Functions..........................................................................................................................51
Reset Initial Conditions ..............................................................................................................54
Input/Output Ports.............................................................................................. 57
Pull-high Resistors......................................................................................................................57
Port A Wake-up...........................................................................................................................58
I/O Port Control Registers...........................................................................................................58
I/O Port Source Current Control..................................................................................................58
Pin-remapping Functions............................................................................................................60
I/O Pin Structures........................................................................................................................61
Programming Considerations......................................................................................................61
Timer Modules – TM........................................................................................... 62
Introduction.................................................................................................................................62
Rev. 1.20
3
September 10, 2020
HT66F0195
A/D Flash MCU with EEPROM
TM Operation..............................................................................................................................62
TM Clock Source.........................................................................................................................62
TM Interrupts...............................................................................................................................63
TM External Pins.........................................................................................................................63
TM Input/Output Pin Control Register.........................................................................................63
Programming Considerations......................................................................................................65
Compact Type TM – CTM................................................................................... 66
Compact Type TM Operation......................................................................................................66
Compact Type TM Register Description.....................................................................................67
Compact Type TM Operating Modes..........................................................................................70
Standard Type TM – STM................................................................................... 76
Standard Type TM Operation......................................................................................................76
Standard Type TM Register Description.....................................................................................76
Standard Type TM Operation Modes..........................................................................................81
Periodic Type TM – PTM..................................................................................... 91
Periodic Type TM Operation.......................................................................................................91
Periodic Type TM Register Description.......................................................................................91
Periodic Type TM Operation Modes............................................................................................96
Analog to Digital Converter – ADC.................................................................. 105
A/D Converter Overview...........................................................................................................105
A/D Converter Register Description..........................................................................................106
A/D Converter Reference Voltage............................................................................................. 110
A/D Converter Input Signals...................................................................................................... 111
A/D Converter Operation........................................................................................................... 111
A/D Conversion Rate and Timing Diagram............................................................................... 112
Summary of A/D Conversion Steps........................................................................................... 113
Programming Considerations.................................................................................................... 114
A/D Conversion Function.......................................................................................................... 114
A/D Converter Programming Examples.................................................................................... 115
Comparator....................................................................................................... 117
Comparator Operation.............................................................................................................. 117
Comparator Interrupt................................................................................................................. 118
Programming Considerations.................................................................................................... 118
Serial Interface Module – SIM.......................................................................... 119
SPI Interface............................................................................................................................. 119
I2C Interface..............................................................................................................................127
UART Interface.................................................................................................. 137
UART External Pins..................................................................................................................138
UART Data Transfer Scheme...................................................................................................138
UART Status and Control Registers.........................................................................................139
Baud Rate Generator................................................................................................................144
UART Setup and Control..........................................................................................................145
UART Transmitter.....................................................................................................................146
UART Receiver.........................................................................................................................147
Rev. 1.20
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September 10, 2020
HT66F0195
A/D Flash MCU with EEPROM
Managing Receiver Errors........................................................................................................149
UART Interrupt Structure..........................................................................................................150
UART Power Down and Wake-up.............................................................................................151
SCOM/SSEG Function for LCD........................................................................ 152
LCD Operation..........................................................................................................................152
LCD Control Registers..............................................................................................................153
Low Voltage Detector – LVD............................................................................ 156
LVD Register.............................................................................................................................156
LVD Operation...........................................................................................................................157
Interrupts........................................................................................................... 158
Interrupt Registers.....................................................................................................................158
Interrupt Operation....................................................................................................................162
External Interrupt.......................................................................................................................163
Comparator Interrupt.................................................................................................................164
Multi-function Interrupts.............................................................................................................164
A/D Converter Interrupt.............................................................................................................164
Time Base Interrupts.................................................................................................................164
Serial Interface Module Interrupt...............................................................................................166
UART Transfer Interrupt............................................................................................................166
LVD Interrupt.............................................................................................................................166
EEPROM Write Interrupt...........................................................................................................166
Timer Module Interrupts ...........................................................................................................167
Interrupt Wake-up Function.......................................................................................................167
Programming Considerations....................................................................................................167
Configuration Options...................................................................................... 168
Application Circuits.......................................................................................... 168
Instruction Set................................................................................................... 169
Introduction...............................................................................................................................169
Instruction Timing......................................................................................................................169
Moving and Transferring Data...................................................................................................169
Arithmetic Operations................................................................................................................169
Logical and Rotate Operation...................................................................................................170
Branches and Control Transfer.................................................................................................170
Bit Operations...........................................................................................................................170
Table Read Operations.............................................................................................................170
Other Operations.......................................................................................................................170
Instruction Set Summary................................................................................. 171
Table Conventions.....................................................................................................................171
Instruction Definition........................................................................................ 173
Package Information........................................................................................ 182
24-pin SSOP (150mil) Outline Dimensions...............................................................................183
28-pin SSOP (150mil) Outline Dimensions...............................................................................184
Rev. 1.20
5
September 10, 2020
HT66F0195
A/D Flash MCU with EEPROM
Features
CPU Features
• Operating Voltage
♦ fSYS=8MHz: 2.2V~5.5V
♦ fSYS=12MHz: 2.7V~5.5V
♦ fSYS=16MHz: 3.3V~5.5V
• Up to 0.25μs instruction cycle with 16MHz system clock at VDD=5V
• Power down and wake-up functions to reduce power consumption
• Oscillators
♦ External High Speed Crystal – HXT
♦ Internal High Speed RC – HIRC
♦ External Low Speed 32.768kHz Crystal – LXT
♦ Internal 32kHz RC – LIRC
• Multi-mode operation: NORMAL, SLOW, IDLE and SLEEP
• Fully integrated oscillators require no external components
• All instructions executed in one or two instruction cycles
• Table read instructions
• 61 powerful instructions
• 8-level subroutine nesting
• Bit manipulation instruction
Peripheral Features
• Flash Program Memory: 8K×16
• RAM Data Memory: 512×8
• True EEPROM Memory: 128×8
• Watchdog Timer function
• 26 bidirectional I/O lines
• Two external interrupt lines shared with I/O pins
• Programmable I/O port source current for LED applications
• Multiple Timer Modules for time measure, input capture, compare match output, PWM output
function or single pulse output function
• Serial Interfaces Module – SIM for SPI or I2C
• Fully-duplex Universal Asynchronous Receiver and Transmitter Interface – UART
• Software controlled 6-SCOM/SSEG and 18-SSEG lines LCD driver with 1/3 bias
• 12 external channels 12-bit resolution A/D converter
• One comparator function
• Dual Time-Base function for generation of fixed time interrupt signals
• Low voltage reset function
• Low voltage detect function
• Flash program memory can be re-programmed up to 10,000 times
• Flash program memory data retention > 10 years
• True EEPROM data memory can be re-programmed up to 100,000 times
• True EEPROM data memory data retention > 10 years
• Package types: 24-pin SSOP, 28-pin SSOP
Rev. 1.20
6
September 10, 2020
HT66F0195
A/D Flash MCU with EEPROM
General Description
The device is a Flash Memory type 8-bit high performance RISC architecture microcontroller.
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 as well as an area of true EEPROM memory for storage of non-volatile data such as serial
numbers, calibration data etc.
Analog features include a multi-channel 12-bit A/D converter and a comparator function. Multiple
and extremely flexible Timer Modules provide timing, pulse generation and PWM generation
functions. Communication with the outside world is catered for by including fully integrated
SPI, I2C, and UART interface functions, three popular interfaces which provide designers with a
means of easy communication with external peripheral hardware. 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 external and internal low and high oscillator functions are provided including
fully integrated system oscillators which require 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 device will find excellent use in applications such as electronic metering,
environmental monitoring, handheld instruments, household appliances, electronically controlled
tools, motor driving in addition to many others.
Block Diagram
INT0~
INT1
ROM
8K × 16
Interrupt
Controller
Pin-Shared
With Port B
RAM
512 × 8
EEPROM
128 × 8
Stack
8-Level
Watchdog
Timer
LVD/LVR
SIM
UART
I/O
HT8 MCU Core
S/W LCD Driver
SYSCLK
OSC2
Pin-Shared
With Port B & C
VDD&AVDD
VDD
VSS&AVSS
VSS
HXT
Port C Driver
PC0~PC6
Port D Driver
PD0~PD3
VREFI
VREF
MUX
OSC1
PB0~PB6
VDD
MUX
HIRC
8/12/16MHz
Port B Driver
1.04V
PGA
Bus
LXT
MUX
LIRC
32kHz
PA0~PA7
Digital Peripherals
Time Bases
XT1
XT2
Pin-Remapping
Function
Timers
Port A Driver
12-bit
ADC
M
U
X
Analog to Digital
Converter
Clock System
VDD
VDD/2
VDD/4
VR
VR/2
VR/4
AN0~AN11
Pin-Shared
With Port A
+
Reset
Circuit
C+
-
C-
CMP
CX
Comparator
Analog Peripherals
: Pin-Shared Node
Rev. 1.20
Pin-Shared
With Port A & B
2
: SIM including SPI and I C
7
September 10, 2020
HT66F0195
A/D Flash MCU with EEPROM
Pin Assignment
VSS&AVSS
VDD&AVSS
1
2
24
PC0/SSEG19/OSC1
23
PB0/INT0/SSEG18/AN0/XT1
PC1/SSEG20/OSC2
3
22
PB1/INT1/SSEG17/AN1/XT2
PC2/[SDO]/SSEG0/SCOM0
4
21
PB2/STCK/SSEG16/AN2
PA0/STP/ICPDA/OCDSDA
5
20
PA4/PTCK/SSEG15/AN3
PC4/SDI/SDA/SSEG22
6
19
PD2/TX/SSEG13
PC5/SCK/SCL/SSEG1/SCOM1
7
18
PD1/RX/SSEG12
PA1/[SDO]/SSEG2/SCOM2
8
17
PA5/SSEG10/AN4/VREFI
PA2/ICPCK/OCDSCK
9
16
PA6/CTCK/SSEG9/AN5/VREF
PA3/[SDI/SDA]/CX/SSEG3/SCOM3/AN11
10
15
PA7/PTP/SSEG8/AN6
PB6/[SCK/SCL]/C+/SSEG4/SCOM4/AN10
11
12
14
PB3/[TX]/CTP/SSEG7/AN7
13
PB4/[RX]/CLO/SSEG6/AN8
PB5/[SCS]/C-/SSEG5/SCOM5/AN9
HT66F0195/HT66V0195
24 SSOP-A
VDD&AVDD
VSS&AVSS
1
28
PC0/SSEG19/OSC1
2
27
PB0/INT0/SSEG18/AN0/XT1
PC1/SSEG20/OSC2
3
26
PB1/INT1/SSEG17/AN1/XT2
PC2/[SDO]/SSEG0/SCOM0
4
25
PB2/STCK/SSEG16/AN2
PA0/STP/ICPDA/OCDSDA
PC3/SDO/SSEG21
PC4/SDI/SDA/SSEG22
5
24
PA4/PTCK/SSEG15/AN3
6
23
PD3/SSEG14
7
22
PD2/TX/SSEG13
PC5/SCK/SCL/SSEG1/SCOM1
8
9
21
20
PD1/RX/SSEG12
PA1/[SDO]/SSEG2/SCOM2
PA2/ICPCK/OCDSCK
10
19
11
18
PA5/SSEG10/AN4/VREFI
PA6/CTCK/SSEG9/AN5/VREF
PC6/SCS/SSEG23
PD0/SSEG11
PA3/[SDI/SDA]/CX/SSEG3/SCOM3/AN11
12
17
PA7/PTP/SSEG8/AN6
PB6/[SCK/SCL]/C+/SSEG4/SCOM4/AN10
13
16
PB3/[TX]/CTP/SSEG7/AN7
PB5/[SCS]/C-/SSEG5/SCOM5/AN9
14
15
PB4/[RX]/CLO/SSEG6/AN8
HT66F0195/HT66V0195
28 SSOP-A
Note: 1. If the pin-shared pin functions have multiple outputs simultaneously, pin names at the right side of the “/”
sign can be used for higher priority.
2. VDD&AVDD means the VDD and AVDD are double bonding; VSS&AVSS means the VSS and AVSS are
double bonding.
3. The OCDSDA and OCDSCK pins are used as the OCDS dedicated pins and only available for the HT66V0195
device which is the OCDS EV chip of the HT66F0195.
4. For the less pin count package type there will be unbounded pins which should be properly configured
to avoid unwanted power consumption resulting from floating input conditions. Refer to the “Standby
Current Considerations” and “Input/Output Ports” sections.
Rev. 1.20
8
September 10, 2020
HT66F0195
A/D Flash MCU with EEPROM
Pin Description
The function of each pin is listed in the following table, however the details behind how each pin
is configured is contained in other sections of the datasheet. As the Pin Description table shows the
situation for the package with the most pins, not all pins in the tables will be available on smaller
package sizes.
Pin Name
PA0/STP/ICPDA/OCDSDA
Function
OPT
PA0
PAWU
PAPU
ST
General purpose I/O. Register enabled pull-up
CMOS
and wake-up.
STP
TMPC
ST
CMOS STM input/output
PA3/[SDI/SDA]/CX/SSEG3/
SCOM3/AN11
PA4/PTCK/SSEG15/AN3
PA5/SSEG10/AN4/VREFI
PA6/CTCK/SSEG9/AN5/
VREF
Rev. 1.20
O/T
Description
ICPDA
—
ST
CMOS ICP Data/Address pin
OCDSDA
—
ST
CMOS OCDS Data/Address pin, for EV chip only.
PA1
PAWU
PAPU
ST
CMOS
[SDO]
SIMC0
IFS
—
CMOS SPI data output
SSEG2
SLCDC0
SLCDC1
—
SSEG Software controlled LCD segment output
SCOM2
SLCDC0
SLCDC1
—
SCOM Software controlled LCD common output
PA2
PAWU
PAPU
ST
CMOS
CMOS ICP Clock pin
PA1/[SDO]/SSEG2/SCOM2
PA2/ICPCK/OCDSCK
I/T
General purpose I/O. Register enabled pull-up
and wake-up.
General purpose I/O. Register enabled pull-up
and wake-up.
ICPCK
—
ST
OCDSCK
—
ST
—
PA3
PAWU
PAPU
ST
CMOS
[SDI]
SIMC0
IFS
ST
—
[SDA]
SIMC0
IFS
ST
NMOS I2C address/data line
CX
CPC
—
CMOS Comparator output
SSEG3
SLCDC0
SLCDC1
—
SSEG Software controlled LCD segment output
SCOM3
SLCDC0
SLCDC1
—
SCOM Software controlled LCD common output
AN11
ACERH
AN
—
PA4
PAWU
PAPU
ST
CMOS
PTCK
PTMC0
ST
SSEG15 SLCDC3
—
—
OCDS Clock pin, for EV chip only.
General purpose I/O. Register enabled pull-up
and wake-up.
SPI data input
A/D Converter analog input
General purpose I/O. Register enabled pull-up
and wake-up.
PTM clock input
SSEG Software controlled LCD segment output
AN3
ACERL
AN
—
PA5
PAWU
PAPU
ST
CMOS
—
SSEG Software controlled LCD segment output
SSEG10 SLCDC2
A/D Converter analog input
General purpose I/O. Register enabled pull-up
and wake-up.
AN4
ACERL
AN
—
A/D Converter analog input
VREFI
SADC2
AN
—
A/D Converter PGA voltage input
PA6
PAWU
PAPU
ST
CMOS
—
General purpose I/O. Register enabled pull-up
and wake-up.
CTCK
CTMC0
ST
SSEG9
SLCDC2
—
CTM clock input
AN5
ACERL
AN
—
A/D Converter analog input
VREF
SADC2
—
AN
A/D Converter reference voltage output
SSEG Software controlled LCD segment output
9
September 10, 2020
HT66F0195
A/D Flash MCU with EEPROM
Pin Name
PA7/PTP/SSEG8/AN6
PB0/INT0/SSEG18/AN0/XT1
PB1/INT1/SSEG17/AN1/XT2
PB2/STCK/SSEG16/AN2
PB3/[TX]/CTP/SSEG7/AN7
PB4/[RX]/CLO/SSEG6/AN8
PB5/[SCS]/C-/SSEG5/
SCOM5/AN9
Function
OPT
PA7
PAWU
PAPU
ST
General purpose I/O. Register enabled pull-up
CMOS
and wake-up.
O/T
Description
PTP
TMPC
ST
CMOS PTM input/output
SSEG8
SLCDC2
—
SSEG Software controlled LCD segment output
AN6
ACERL
AN
PB0
PBPU
ST
INT0
INTEG
INTC0
ST
SSEG18 SLCDC3
—
A/D Converter analog input
CMOS General purpose I/O. Register enabled pull-up.
—
—
External Interrupt 0
SSEG Software controlled LCD segment output
AN0
ACERL
AN
—
A/D Converter analog input
XT1
CO
LXT
—
LXT oscillator pin
PB1
PBPU
ST
INT1
INTEG
INTC2
ST
SSEG17 SLCDC3
CMOS General purpose I/O. Register enabled pull-up.
—
—
ACERL
AN
—
XT2
CO
—
LXT
PB2
PBPU
ST
STCK
STMC0
ST
SSEG16 SLCDC3
External Interrupt 1
SSEG Software controlled LCD segment output
AN1
A/D Converter analog input
LXT oscillator pin
CMOS General purpose I/O. Register enabled pull-up.
—
—
STM clock input
SSEG Software controlled LCD segment output
AN2
ACERL
AN
PB3
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up.
[TX]
UCR1
UCR2
IFS
—
CMOS UART TX serial data output
—
A/D Converter analog input
CTP
TMPC
—
CMOS CTM output
SSEG7
SLCDC2
—
SSEG Software controlled LCD segment output
AN7
ACERL
AN
PB4
PBPU
ST
[RX]
UCR1
UCR2
IFS
ST
—
A/D Converter analog input
CMOS General purpose I/O. Register enabled pull-up.
—
UART RX serial data input
CLO
TMPC
—
CMOS System clock output
SSEG6
SLCDC2
—
SSEG Software controlled LCD segment output
AN8
ACERH
AN
PB5
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up.
SCS
SIMC0
SIMC2
IFS
ST
CMOS SPI slave select
C-
CPC
AN
SSEG5
SLCDC1
—
SSEG Software controlled LCD segment output
—
SCOM Software controlled LCD common output
SCOM5 SLCDC1
AN9
Rev. 1.20
I/T
ACERH
AN
10
—
—
—
A/D Converter analog input
Comparator negative input
A/D Converter analog input
September 10, 2020
HT66F0195
A/D Flash MCU with EEPROM
Pin Name
PB6/[SCK/SCL]/C+/SSEG4/
SCOM4/AN10
Function
OPT
I/T
PB6
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up.
[SCK]
SIMC0
IFS
ST
CMOS SPI serial clock
[SCL]
SIMC0
IFS
ST
NMOS I2C clock line
C+
CPC
AN
SSEG4
SLCDC1
—
SSEG Software controlled LCD segment output
—
SCOM Software controlled LCD common output
SCOM4 SLCDC1
PC0/SSEG19/OSC1
PC1/SSEG20/OSC2
PC3/SDO/SSEG21
AN
PC0
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
—
SSEG Software controlled LCD segment output
SSEG19 SLCDC3
CO
HXT
PC1
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
—
SSEG Software controlled LCD segment output
SSEG20 SLCDC3
—
PC2
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
[SDO]
SIMC0
IFS
—
CMOS SPI data output
SSEG0
SLCDC0
SLCDC1
—
SSEG Software controlled LCD segment output
SCOM0
SLCDC0
SLCDC1
—
SCOM Software controlled LCD common output
PC3
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
SDO
SIMC0
IFS
—
CMOS SPI data output
HXT oscillator pin
—
SSEG Software controlled LCD segment output
PC4
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
SDI
SIMC0
IFS
ST
SDA
SIMC0
IFS
ST
—
SPI data input
NMOS I2C data line
—
SSEG Software controlled LCD segment output
PC5
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
SCK
SIMC0
IFS
ST
CMOS SPI serial clock
SCL
SIMC0
IFS
ST
NMOS I2C clock line
SSEG1
SLCDC0
SLCDC1
—
SSEG Software controlled LCD segment output
SCOM1
SLCDC0
SLCDC1
—
SCOM Software controlled LCD common output
PC6
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
SCS
SIMC0
SIMC2
IFS
ST
CMOS SPI slave select
SSEG23 SLCDC4
Rev. 1.20
HXT
HXT oscillator pin
CO
SSEG22 SLCDC4
PD0/SSEG11
—
A/D Converter analog input
OSC1
PC4/SDI/SDA/SSEG22
PC6/SCS/SSEG23
—
Comparator positive input
ACERH
SSEG21 SLCDC3
PC5/SCK/SCL/SSEG1/
SCOM1
—
Description
AN10
OSC2
PC2/[SDO]/SSEG0/SCOM0
O/T
PD0
PDPU
SSEG11 SLCDC2
—
SSEG Software controlled LCD segment output
ST
CMOS General purpose I/O. Register enabled pull-up.
—
SSEG Software controlled LCD segment output
11
September 10, 2020
HT66F0195
A/D Flash MCU with EEPROM
Pin Name
PD1/RX/SSEG12
Function
OPT
I/T
PD1
PDPU
ST
RX
UCR1
UCR2
IFS
ST
SSEG12 SLCDC2
PD2/TX/SSEG13
VDD&AVDD *
VSS&AVSS *
Description
—
UART RX serial data input
—
SSEG Software controlled LCD segment output
PD2
PDPU
ST
CMOS General purpose I/O. Register enabled pull-up.
TX
UCR1
UCR2
IFS
—
CMOS UART TX serial data output
—
SSEG Software controlled LCD segment output
ST
CMOS General purpose I/O. Register enabled pull-up.
─
SSEG Software controlled LCD segment output
SSEG13 SLCDC2
PD3/SSEG14
O/T
CMOS General purpose I/O. Register enabled pull-up.
PD3
PDPU
SSEG14 SLCDC3
VDD
—
PWR
—
Positive power supply
AVDD
—
PWR
—
Analog positive power supply
VSS
—
PWR
—
Negative power supply, ground.
AVSS
—
PWR
—
Analog negative power supply, ground.
Legend: I/T: Input type;
O/T: Output type;
OPT: Optional by configuration option (CO) or register option;
CO: Configuration option;
PWR: Power;
AN: Analog signal;
ST: Schmitt Trigger input;
CMOS: CMOS output;
NMOS; NMOS output;
SSEG: Software controlled LCD SEG;
SCOM: Software controlled LCD COM;
HXT: High frequency crystal oscillator;
LXT: Low frequency crystal oscillator
*: The AVDD pin is internal bonded together with the VDD pin while the AVSS pin is internally bonded
together with the VSS pin.
Absolute Maximum Ratings
Supply Voltage...................................................................................................VSS−0.3V to VSS+6.0V
Input Voltage..................................................................................................... VSS−0.3V to VDD+0.3V
Storage Temperature...................................................................................................... -50°C to 125°C
Operating Temperature.................................................................................................... -40°C to 85°C
IOH Total....................................................................................................................................... -80mA
IOL Total........................................................................................................................................ 80mA
Total Power Dissipation............................................................................................................ 500mW
Note: These are stress ratings only. Stresses exceeding the range specified under “Absolute
Maximum Ratings” may cause substantial damage to the device. Functional operation of
the devices at other conditions beyond those listed in the specification is not implied and
prolonged exposure to extreme conditions may affect device reliability.
Rev. 1.20
12
September 10, 2020
HT66F0195
A/D Flash MCU with EEPROM
D.C. Characteristics
Ta=-40°C~85°C
Symbol
Parameter
Operating Voltage (HXT)
Test Conditions
Min.
Typ.
Max.
fSYS=fHXT=8MHz
2.2
—
5.5
fSYS=fHXT=12MHz
2.7
—
5.5
fSYS=fHXT=16MHz
3.3
—
5.5
fSYS=fHIRC=8MHz
2.2
—
5.5
fSYS=fHIRC=12MHz
2.7
—
5.5
fSYS=fHIRC=16MHz
3.3
—
5.5
fSYS=fH=fHXT=8MHz,
No load, all peripherals off
—
1.0
1.5
—
2.0
3.0
fSYS=fH=fHXT=12MHz,
No load, all peripherals off
—
1.5
2.75
—
3.0
4.5
—
4.5
7.0
fSYS=fH=fHIRC=8MHz,
No load, all peripherals off
—
1.0
1.5
—
2.0
3.0
fSYS=fH=fHIRC=12MHz,
No load, all peripherals off
—
1.5
2.75
—
3.0
4.5
—
4.5
7.0
3V fSYS=fSUB=fLXT=32.768kHz,
—
10
20
5V
No load, all peripherals off
—
30
50
3V
fSYS=fSUB=fLIRC=32kHz,
No load, all peripherals off
—
10
20
—
30
50
No load, all peripherals off,
WDT off
—
—
1
—
—
2
No load, all peripherals off,
WDT on
—
—
3
—
—
5
—
3
5
—
5
10
fSYS=fHXT=8MHz, fSUB on, No load,
all peripherals off
—
0.5
1
—
1
2
fSYS=fHXT=12MHz, fSUB on, No load,
all peripherals off
—
0.6
1.2
—
1.2
2.4
—
2.0
4.0
fSYS=fHIRC=8MHz, fSUB on, No load,
all peripherals off
—
0.8
1.6
—
1.0
2.0
fSYS=fHIRC=12MHz, fSUB on, No load,
all peripherals off
—
1.2
2.4
—
1.5
3.0
4.0
VDD
—
VDD
Operating Voltage (HIRC)
—
3V
5V
Operating Current (HXT)
3V
5V
5V
3V
IDD
5V
Operating Current (HIRC)
3V
5V
5V
Operating Current (LXT)
Operating Current (LIRC)
Standby Current (SLEEP0 Mode)
Standby Current (SLEEP1 Mode)
Standby Current (IDLE0 Mode)
5V
3V
5V
3V
5V
3V
5V
3V
5V
ISTB
Standby Current
(IDLE1 Mode, HXT)
3V
5V
5V
3V
5V
Standby Current
(IDLE1 Mode, HIRC)
VIL
Input Low Voltage for I/O Ports
VIH
Input High Voltage for I/O Ports
Rev. 1.20
3V
5V
Conditions
fSYS=fH=fHXT=16MHz,
no load, all peripherals off
fSYS=fH=fHIRC=16MHz,
No load, all peripherals off
No load, all peripherals off, fSUB on
fSYS=fHXT=16MHz, fSUB on, No load,
all peripherals off
5V
fSYS=fHIRC=16MHz, fSUB on, No load,
all peripherals off
—
2.0
5V
—
0
—
1.5
—
—
0
—
0.2VDD
5V
—
3.5
—
5.0
—
—
0.8VDD
—
VDD
13
Unit
V
V
mA
mA
mA
mA
mA
mA
μA
μA
μA
μA
μA
mA
mA
mA
mA
mA
mA
V
V
September 10, 2020
HT66F0195
A/D Flash MCU with EEPROM
Symbol
IOL
Parameter
Sink Current for I/O Ports
Test Conditions
Min.
Typ.
Max.
16
32
—
32
64
—
-1.0
-2.0
—
-2.0
-4.0
—
VOH=0.9VDD, SLEDCn[m+1, m]=01, -1.75
n=0 or 1; m=0, 2, 4 or 6
-3.5
-3.5
—
-7.0
—
VOH=0.9VDD, SLEDCn[m+1, m]=10,
n=0 or 1; m=0, 2, 4 or 6
-2.5
-5.0
—
-5.0
-10
—
VOH=0.9VDD, SLEDCn[m+1, m]=11,
n=0 or 1; m=0, 2, 4 or 6
-5.5
-11
—
5V
-11
-22
—
3V
—
20
60
100
5V
—
10
30
50
VDD
3V
5V
3V
5V
3V
IOH
Source Current for I/O Ports
5V
3V
5V
3V
RPH
Pull-high Resistance for I/O Ports
Conditions
VOL=0.1VDD
VOH=0.9VDD, SLEDCn[m+1, m]=00,
n=0 or 1; m=0, 2, 4 or 6
A.C. Characteristics
Symbol
Parameter
System Clock (HXT)
fSYS
System Clock (HIRC)
Unit
mA
mA
mA
mA
mA
kΩ
Ta=-40°C~85°C, unless otherwise specify
Test Condition
Min.
Typ.
2.2V~5.5V fSYS=fHXT=8MHz
0.4
—
8
2.7V~5.5V fSYS=fHXT=12MHz
0.4
—
12
3.3V~5.5V fSYS=fHXT=16MHz
0.4
—
16
2.2V~5.5V fSYS=fHIRC=8MHz
—
8
—
2.7V~5.5V fSYS=fHIRC=12MHz
—
12
—
3.3V~5.5V fSYS=fHIRC=16MHz
—
16
—
VDD
Condition
Max.
Unit
MHz
MHz
System Clock (LXT)
2.2~5.5V fSYS=fLXT=32.768kHz
—
32.768
—
kHz
System Clock (LIRC)
2.2~5.5V fSYS=fLIRC=32kHz
—
32
—
kHz
-2%
32
+2%
-10%
32
+10%
5V
Ta=25°C
fLIRC
Low Speed Internal RC oscillator (LIRC)
tSTART
LIRC Start Up Time
—
—
—
—
100
μs
tTCK
xTCK pin Minimum Input Pulse Width
—
—
0.3
—
—
μs
tINT
Interrupt Pin Minimum Input Pulse Width
—
—
10
—
—
μs
128
—
—
tHXT
tHIRC
System Start-up Timer Period
(Wake-up from Condition where fSYS is off)
tSST
System Start-up Timer Period
(Wake-up from Condition where fSYS is on)
2.2V~5.5V Ta=-40°C to 85°C
kHz
—
fSYS=fHXT~fHXT/64
—
fSYS=fHIRC~fHIRC/64
16
—
—
—
fSYS=fLXT
128
—
—
tLXT
—
fSYS=fLIRC
2
—
—
tLIRC
—
fSYS=fH~fH/64,
fH=fHXT or fHIRC
2
—
—
tH
—
fSYS=fLXT or fLIRC
2
—
—
tSUB
System Start-up Timer Period
(WDT Time-out Hardware Cold Reset)
—
—
0
—
—
tH
System Reset Delay Time
(Power-on Reset, LVR Hardware Reset,
LVRC/WDTC Software Reset)
—
—
25
50
100
ms
System Reset Delay Time
(WDT Time-out Hardware Cold Reset)
—
—
8.3
16.7
33.3
ms
tEERD
EEPROM Read Time
—
—
—
—
4
tSYS
tEEWR
EEPROM Write Time
—
—
—
4
6
ms
tRSTD
Note: tSYS=1/fSYS
Rev. 1.20
14
September 10, 2020
HT66F0195
A/D Flash MCU with EEPROM
HIRC Electrical Characteristics
During the program writing operation the writer will trim the HIRC oscillator at a user selected
HIRC frequency and user selected voltage of either 3V or 5V.
Symbol
Test Conditions
Parameter
Typ.
Max.
25°C
-1%
8
+1%
-40°C~85°C
-2%
8
+2%
-2.5%
8
+2.5%
Temp.
3V/5V
8MHz Writer Trimmed HIRC Frequency
25°C
2.2V~5.5V
3V/5V
fHIRC
Min.
VDD
12MHz Writer Trimmed HIRC Frequency
-40°C~85°C
-3%
8
+3%
25°C
-1%
12
+1%
-40°C~85°C
-2%
12
+2%
-2.5%
12
+2.5%
-40°C~85°C
-3%
12
+3%
25°C
-1%
16
+1%
-40°C~85°C
-2%
16
+2%
-2.5%
16
+2.5%
-3%
16
+3%
25°C
2.7V~5.5V
5V
16MHz Writer Trimmed HIRC Frequency
25°C
3.3V~5.5V
-40°C~85°C
Unit
MHz
MHz
MHz
Note: 1. The 3V/5V values for VDD are provided as these are the two selectable fixed voltages at which the HIRC
frequency is trimmed by the writer.
2. The row below the 3V/5V trim voltage row is provided to show the values for the full VDD range operating
voltage. It is recommended that the trim voltage is fixed at 3V for application voltage ranges from 2.2V to
3.6V and fixed at 5V for application voltage ranges from 3.3V to 5.5V.
3. The minimum and maximum tolerance values provided in the table are for the frequency at which the
writer trims the HIRC oscillator.
A/D Converter Electrical Characteristics
Ta=-40°C~85°C
Symbol
Parameter
Test Conditions
VDD
Conditions
Min.
Typ.
Max.
Unit
VDD
Operating Voltage
—
—
2.2
—
5.5
V
VADI
Input Voltage
—
—
0
—
VREF
V
VREF
Reference Voltage
—
—
2
—
VDD
V
-3
—
+3
LSB
-4
—
+4
LSB
—
1.0
2.0
—
1.5
3.0
3V
DNL
Differential Non-linearity
5V
3V
5V
3V
INL
Integral Non-linearity
5V
3V
5V
3V
VREF=VDD, tADCK=0.5μs
VREF=VDD, tADCK=10μs
VREF=VDD, tADCK=0.5μs
VREF=VDD, tADCK=10μs
IADC
Additional Current for A/D Converter Enable
tADCK
Clock Period
—
—
0.5
—
10
μs
tADC
Conversion Time (Includes A/D Sample and
Hold Time)
—
—
—
16
—
tADCK
tON2ST
A/D Converter On-to-Start Time
—
—
4
—
—
μs
Rev. 1.20
5V
15
No load, tADCK=0.5μs
mA
September 10, 2020
HT66F0195
A/D Flash MCU with EEPROM
LVD/LVR Electrical Characteristics
Ta=-40°C~85°C
Symbol
VLVR
VLVD
Test Conditions
Parameter
VDD
Low Voltage Reset Voltage
—
Low Voltage Detector Voltage
—
Min. Typ. Max. Unit
Conditions
LVR Enable, voltage select 2.1V
2.1
LVR Enable, voltage select 2.55V
2.55
-5%
LVR Enable, voltage select 3.15V
3.15
LVR Enable, voltage select 3.8V
3.8
LVD Enable, voltage select 2.0V
2.0
LVD Enable, voltage select 2.2V
2.2
LVD Enable, voltage select 2.4V
2.4
LVD Enable, voltage select 2.7V
2.7
-5%
LVD Enable, voltage select 3.0V
3.0
LVD Enable, voltage select 3.3V
3.3
LVD Enable, voltage select 3.6V
3.6
LVD Enable, voltage select 4.0V
IOP
tLVDS
Operating Current
+5%
V
+5%
V
4.0
5V LVD enable, LVR enable, VBGEN=0
─
20
25
5V LVD enable, LVR enable, VBGEN=1
─
180
200
—
For LVR enable, VBGEN=0,
LVD off → on
─
─
15
—
For LVR disable, VBGEN=0,
LVD off → on
─
─
150
LVDO Stable Time
μA
μs
tLVR
Minimum Low Voltage Width to Reset
—
—
120
240
480
μs
tLVD
Minimum Low Voltage Width to
Interrupt
—
—
60
120
240
μs
Internal Bandgap Reference Voltage Electrical Characteristics
Ta=-40°C~85°C
Symbol
Parameter
Test Conditions
VDD
VBG
Bandgap Reference Voltage
—
tBGS
VBG Turn On Stable Time
—
Conditions
—
No load
Min.
Typ.
Max.
Unit
-3%
1.04
+3%
V
—
—
150
μs
Note: The VBG voltage is used as the A/D converter PGA input.
Comparator Electrical Characteristics
Ta=-40°C~85°C
Symbol
VDD
Parameter
Operating Voltage
ICMP
Additional Current for Comparator Enable
VOS
Input Offset Voltage
VCM
Common Mode Voltage Range
AOL
Open Loop Gain
Rev. 1.20
Test Conditions
VDD
Conditions
Min.
Typ.
Max.
Unit
V
—
—
2.2
—
5.5
3V
—
—
37
56
5V
—
—
130
200
3V
—
-10
—
10
5V
—
-10
—
10
—
—
VSS
—
VDD-1.4
3V
—
60
80
—
5V
—
60
80
—
16
μA
mV
V
dB
September 10, 2020
HT66F0195
A/D Flash MCU with EEPROM
Symbol
Test Conditions
Parameter
VDD
Conditions
3V
VHYS
3V
3V
Response Time
Max.
0
0
5
0
0
5
40
60
80
40
60
80
—
370
560
—
370
560
CHYEN=1
5V
tRP
Typ.
CHYEN=0
5V
Hysteresis
Min.
With 100mV overdrive
5V
Unit
mV
mV
ns
Note: All measurement is under the condition where the comparator positive input voltage is equal to (VDD-1.4)/2
and remains constant.
Software Controlled LCD Driver Electrical Characteristics
Ta=-40°C~85°C
Symbol
Test Conditions
Parameter
VDD
Conditions
5V
Min.
Typ.
Max.
ISEL[1:0]=00
4.2
8.3
13
ISEL[1:0]=01
8.3
16.7
25
ISEL[1:0]=10
25
50
75
ISEL[1:0]=11
Unit
IBIAS
Bias Current
μA
50
100
150
VLCD_H
VDD×2/3 Voltage for LCD SCOM/SSEG
2.2V~5.5V No load
Output
0.645
0.67
0.695
VDD
VLCD_L
VDD×1/3 Voltage for LCD SCOM/SSEG
2.2V~5.5V No load
Output
0.305
0.33
0.355
VDD
Power-on Reset Characteristics
Ta=25°C
Symbol
Test Conditions
Parameter
VDD
Conditions
Min.
Typ.
Max.
Unit
VPOR
VDD Start Voltage to Ensure Power-on Reset
—
—
—
—
100
mV
RRPOR
VDD Rising Rate to Ensure Power-on Reset
—
—
0.035
—
—
V/ms
tPOR
Minimum Time for VDD Stays at VPOR to
Ensure Power-on Reset
—
—
1
—
—
ms
VDD
tPOR
RRPOR
VPOR
Rev. 1.20
17
Time
September 10, 2020
HT66F0195
A/D Flash MCU with EEPROM
System Architecture
A key factor in the high-performance features of the Holtek range of microcontrollers is attributed
to their internal system architecture. The device takes 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 which need one more cycle. An 8-bit wide ALU is used in practically
all instruction set operations, which carries out arithmetic operations, logic operations, rotation,
increment, decrement, branch decisions, etc. The internal data path is simplified by moving data
through the Accumulator and the ALU. Certain internal registers are implemented in the Data
Memory and can be directly or indirectly addressed. The simple addressing methods of these
registers along with additional architectural features ensure that a minimum of external components
is required to provide a functional I/O and A/D control system with maximum reliability and
flexibility. This makes the device suitable for low-cost, high-volume production for controller
applications.
Clocking and Pipelining
The main system clock, derived from either an 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.
fSYS
(System Clock)
Phase Clock T1
Phase Clock T2
Phase Clock T3
Phase Clock T4
Program Counter
Pipelining
PC
PC+1
PC+2
Fetch Inst. (PC)
Execute Inst. (PC-1)
Fetch Inst. (PC+1)
Execute Inst. (PC)
Fetch Inst. (PC+2)
Execute Inst. (PC+1)
System Clocking and Pipelining
Rev. 1.20
18
September 10, 2020
HT66F0195
A/D Flash MCU with EEPROM
For instructions involving branches, such as jump or call instructions, two machine cycles are
required to complete instruction execution. An extra cycle is required as the program takes one
cycle to first obtain the actual jump or call address and then another cycle to actually execute the
branch. The requirement for this extra cycle should be taken into account by programmers in timing
sensitive applications.
1
MOV A,[12H]
2
CALL DELAY
3
CPL [12H]
4
:
5
:
6 DELAY: NOP
Fetch Inst. 1
Execute Inst. 1
Fetch Inst. 2
Execute Inst. 2
Fetch Inst. 3
Flush Pipeline
Fetch Inst. 6
Execute Inst. 6
Fetch Inst. 7
Instruction Fetching
Program Counter
During program execution, the Program Counter is used to keep track of the address of the
next instruction to be executed. It is automatically incremented by one each time an instruction
is executed except for instructions, such as “JMP” or “CALL” that demands a jump to a nonconsecutive Program Memory address. Only the lower 8 bits, known as the Program Counter Low
Register, are directly addressable by the application program.
When executing instructions requiring jumps to non-consecutive addresses such as a jump
instruction, a subroutine call, interrupt or reset, etc., the microcontroller manages program control
by loading the required address into the Program Counter. For conditional skip instructions, once
the condition has been met, the next instruction, which has already been fetched during the present
instruction execution, is discarded and a dummy cycle takes its place while the correct instruction is
obtained.
Program Counter
Program Counter High Byte
PCL Register
PC12~PC8
PCL7~PCL0
Program Counter
The lower byte of the Program Counter, known as the Program Counter Low register or PCL, is
available for program control and is a readable and writeable register. By transferring data directly
into this register, a short program jump can be executed directly. However, as only this low byte
is available for manipulation, the jumps are limited to the present page of memory that is 256
locations. When such program jumps are executed it should also be noted that a dummy cycle
will be inserted. Manipulating the PCL register may cause program branching, so an extra cycle is
needed to pre-fetch.
Rev. 1.20
19
September 10, 2020
HT66F0195
A/D Flash MCU with EEPROM
Stack
This is a special part of the memory which is used to save the contents of the Program Counter only.
The stack is organized into multiple levels and neither part of the data nor part of the program space,
and is neither readable nor writeable. The activated level is indexed by the Stack Pointer, and is
neither readable nor writeable. At a subroutine call or interrupt acknowledge signal, the contents of
the Program Counter are pushed onto the stack. At the end of a subroutine or an interrupt routine,
signaled by a return instruction, RET or RETI, the Program Counter is restored to its previous value
from the stack. After a device reset, the Stack Pointer will point to the top of the stack.
If the stack is full and an enabled interrupt takes place, the interrupt request flag will be recorded but
the acknowledge signal will be inhibited. When the Stack Pointer is decremented, by RET or RETI,
the interrupt will be serviced. This feature prevents stack overflow allowing the programmer to use
the structure more easily. However, when the stack is full, a CALL subroutine instruction can still
be executed which will result in a stack overflow. Precautions should be taken to avoid such cases
which might cause unpredictable program branching.
If the stack is overflow, the first Program Counter save in the stack will be lost.
Program Counter
Top of Stack
Stack Level 1
Stack Level 2
Stack
Pointer
Stack Level 3
Bottom of Stack
Stack Level 8
:
:
:
Program Memory
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
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A/D Flash MCU with EEPROM
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 offer 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 8K×16 bits. The Program Memory is addressed by the Program
Counter and also contains data, table information and interrupt entries. Table data, which can be
arranged in any location within the Program Memory, is addressed by a separate table pointer register.
0000H
Initialisation Vector
0004H
Interrupt Vectors
002CH
n00H
nFFH
1FFFH
Look-up Table
16 bits
Program Memory Structure
Special Vectors
Within the Program Memory, certain locations are reserved for the reset and interrupts. The location
0000H 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 configured by placing
the address of the look up data to be retrieved in the table pointer registers, 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”.
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The accompanying diagram illustrates the addressing data flow of the look-up table.
Program Memory
Address
Last Page or
TBHP Register
TBLP Register
Data
16 bits
Register TBLH
User Selected
Register
High Byte
Low Byte
Table Program Example
The following example shows how the table pointer and table data is defined and retrieved from the
microcontroller. This example uses raw table data located in the Program Memory which is stored
there using the ORG statement. The value at this ORG statement is “1F00H” which refers to the
start address of the last page within the 8K words Program Memory of the device. The table pointer
low byte register is set 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 “1F06H” or 6 locations after the start of
the last page. Note that the value for the table pointer is referenced to the specific address pointed by
the TBLP and TBHP registers 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.
Table Read Program Example
tempreg1 db ? ; temporary register #1
tempreg2 db ? ; temporary register #2
:
:
mov a,06h ; initialise low table pointer - note that this address is referenced
mov tblp,a ; to the last page or the page that tbhp pointed
mov a,1Fh ; initialise high table pointer
mov tbhp,a
:
:
tabrd tempreg1 ; transfers value in table referenced by table pointer,
; data at program memory address “1F06H” transferred to tempreg1 and TBLH
dec tblp ; reduce value of table pointer by one
tabrd tempreg2 ; transfers value in table referenced by table pointer,
; data at program memory address “1F05H” 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 1F00h ; sets initial address of program memory
dc 00Ah, 00Bh, 00Ch, 00Dh, 00Eh, 00Fh, 01Ah, 01Bh
:
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In Circuit Programming – ICP
The provision of Flash type Program Memory provides the user with a means of convenient and
easy upgrades and modifications to their programs on the same device.
As an additional convenience, Holtek has provided a means of programming the microcontroller incircuit using a 4-pin interface. This provides manufacturers with the possibility of manufacturing
their circuit boards complete with a programmed or un-programmed microcontroller, and then
programming or upgrading the program at a later stage. This enables product manufacturers to easily
keep their manufactured products supplied with the latest program releases without removal and reinsertion of the device.
Holtek Writer Pins
MCU Programming Pins
Pin Description
ICPDA
PA0
Programming Serial Data/Address
ICPCK
PA2
Programming Clock
VDD
VDD&AVDD
Power Supply
VSS
VSS&AVSS
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. The technical details regarding the in-circuit
programming of the device are beyond the scope of this document and will be supplied in
supplementary literature.
During the programming process, the user can take care of the ICPDA and ICPCK pins for data and
clock programming purposes to ensure that no other outputs are connected to these two pins.
Writer Connector
Signals
MCU Programming
Pins
Writer_VDD
VDD&AVDD
ICPDA
PA0
ICPCK
PA2
Writer_VSS
VSS&AVSS
*
*
To other Circuit
Note: * may be resistor or capacitor. The resistance of * must be greater than 1kΩ or the capacitance
of * must be less than 1nF.
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On-Chip Debug Support ─ OCDS
There is an EV chip named HT66V0195 which is used to emulate the real MCU device named
HT66F0195. The EV chip device also provides an “On-Chip Debug” function to debug the real
MCU device during the development process. The EV chip and the real MCU device are almost
functionally compatible except for “On-Chip Debug” function. Users can use the EV chip device to
emulate the real chip device behavior by connecting the OCDSDA and OCDSCK pins to the Holtek
HT-IDE development tools. The OCDSDA pin is the OCDS Data/Address input/output pin while
the OCDSCK pin is the OCDS clock input pin. When users use the EV chip for debugging, other
functions which are shared with the OCDSDA and OCDSCK pins in the device will have no effect
in the EV chip. 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&AVDD
Power Supply
VSS
VSS&AVSS
Ground
Data Memory
The Data Memory is a volatile area of 8-bit wide RAM internal memory and is the location where
temporary information is stored.
Structure
Categorised into two types, the first of these is an area of RAM, known as the Special Function Data
Memory. 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 known as the
General Purpose Data Memory, which is reserved for general purpose use. All locations within this
area are read and write accessible under program control.
The overall Data Memory is subdivided into four banks, which are implemented in 8-bit wide
Memory. The Special Purpose Data Memory registers are accessible in all banks, with the exception
of the EEC register at address 40H, which is only accessible in Bank 1. Switching between the
different Data Memory banks is achieved by properly setting the Bank Pointer to the correct value.
The start address of the Data Memory for the device is the address 00H. The address range of the
Special Purpose Data Memory for the device is from 00H to 7FH while the address range of the
General Purpose Data Memory is from 80H to FFH.
Special Purpose
Data Memory
Located Bank
0~3
General Purpose
Data Memory
Capacity
Bank: Address
512×8
0: 80H~FFH
1: 80H~FFH
2: 80H~FFH
3: 80H~FFH
Data Memory Summary
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A/D Flash MCU with EEPROM
00H
40H: EEC
(Bank 1)
Special Purpose
Data Memory
(Bank 0 ~ Bank 3)
7FH
80H
General Purpose
Data Memory
(Bank 0 ~ Bank 3)
Bank 0
Bank 1
Bank 2
Bank 3
FFH
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 bit operation instructions individual bits can be set or reset
under program control giving the user a large range of flexibility for bit manipulation in the Data
Memory.
Special Purpose Data Memory
This area of Data Memory is where registers, necessary for the correct operation of the
microcontroller, are stored. Most of the registers are both readable and writeable but some are
protected and are readable only, the details of which are located under the relevant Special Function
Register section. Note that for locations that are unused, any read instruction to these addresses will
return the value “00H”.
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A/D Flash MCU with EEPROM
00H
01H
02H
03H
04H
05H
06H
07H
08H
09H
0AH
0BH
0CH
0DH
0EH
0FH
10H
11H
12H
13H
14H
15H
16H
17H
18H
19H
1AH
1BH
1CH
1DH
1EH
1FH
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
3AH
3BH
3CH
3DH
3EH
3FH
Bank 0~3
IAR0
MP0
IAR1
MP1
BP
ACC
PCL
TBLP
TBLH
TBHP
STATUS
SMOD
LVDC
INTEG
INTC0
INTC1
INTC2
MFI0
MFI1
MFI2
PA
PAC
PAPU
PAWU
ACERH
TMPC
WDTC
TBC
CTRL
LVRC
EEA
EED
SADOL
SADOH
SADC0
SADC1
SADC2
PB
PBC
PBPU
CTMC0
CTMC1
CTMDL
CTMDH
CTMAL
CTMAH
CTMRP
STMC0
STMC1
STMDL
STMDH
STMAL
STMAH
STMRP
40H
41H
42H
43H
44H
45H
46H
47H
48H
49H
4AH
4BH
4CH
4DH
4EH
4FH
50H
51H
52H
53H
54H
55H
56H
57H
58H
59H
5AH
Bank 0,2,3
Bank 1
EEC
PC
PCC
PCPU
ACERL
SIMC0
SIMC1
SIMD
SIMC2/SIMA
SIMTOC
SLCDC0
SLCDC1
SLCDC2
SLCDC3
SLCDC4
SLEDC0
SLEDC1
IFS
PD
PDC
PDPU
USR
UCR1
UCR2
BRG
TXR_RXR
PTMC0
PTMC1
PTMDL
PTMDH
PTMAL
PTMAH
PTMRPL
PTMRPH
CPC
7FH
: Unused, read as 00H
Special Purpose Data Memory
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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 register together with the
MP1 register can access data from any Data Memory Bank. As the Indirect Addressing Registers are
not physically implemented, reading the Indirect Addressing Registers will return a result of “00H”
and writing to the registers 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 together with IAR1 are
used to access data from all data banks according to the BP register. Direct Addressing can only be
used with Bank 0, all other Banks must be addressed indirectly using MP1 and IAR1.
The following example shows how to clear a section of four Data Memory locations already defined
as locations adres1 to adres4.
Indirect Addressing Program Example
data .section ´data´
adres1 db ?
adres2 db ?
adres3 db ?
adres4 db ?
block db ?
code .section at 0 ´code´
org 00h
start:
mov a,04h ; set size of block
mov block,a
mov a,offset adres1 ; Accumulator loaded with first RAM address
mov mp0,a ; set memory pointer with first RAM address
loop:
clr IAR0 ; clear the data at address defined by mp0
inc mp0 ; increment memory pointer
sdz block ; check if last memory location has been cleared
jmp loop
continue:
The important point to note here is that in the example shown above, no reference is made to specific
Data Memory addresses.
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A/D Flash MCU with EEPROM
Bank Pointer – BP
The Data Memory is divided into four banks, Banks 0~3. Selecting the required Data Memory area
is achieved using the Bank Pointer. Bits 1~0 of the Bank Pointer are used to select Data Memory
Banks 0~3. The Data Memory is initialised to Bank 0 after a reset, except for a WDT time-out reset
in the IDLE or SLEEP 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 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 the indirect addressing.
• BP Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
—
—
DMBP1
DMBP0
R/W
—
—
—
—
—
—
R/W
R/W
POR
—
—
—
—
—
—
0
0
Bit 7~2 Unimplemented, read as “0”
Bit 1~0
DMBP1~DMBP0: Data Memory Bank selection
00: Bank 0
01: Bank 1
10: Bank 2
11: Bank 3
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 pointers and indicate the location
where the table data is located. Their value must be set 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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A/D Flash MCU with EEPROM
Status Register – STATUS
This 8-bit register contains the zero flag (Z), carry flag (C), auxiliary carry flag (AC), overflow flag
(OV), power down flag (PDF), and watchdog time-out flag (TO). These arithmetic/logical operation
and system management flags are used to record the status and operation of the microcontroller.
With the exception of the TO and PDF flags, bits in the status register can be altered by instructions
like most other registers. Any data written into the status register will not change the TO or PDF flag.
In addition, operations related to the status register may give different results due to the different
instruction operations. The TO flag can be affected only by a system power-up, a WDT time-out or
by executing the “CLR WDT” or “HALT” instruction. The PDF flag is affected only by executing
the “HALT” or “CLR WDT” instruction or during a system power-up.
The Z, OV, AC, and C flags generally reflect the status of the latest operations.
• C is set if an operation results in a carry during an addition operation or if a borrow does not take
place during a subtraction operation; otherwise C is cleared. C is also affected by a rotate through
carry instruction.
• AC is set if an operation results in a carry out of the low nibbles in addition, or no borrow from
the high nibble into the low nibble in subtraction; otherwise AC is cleared.
• Z is set if the result of an arithmetic or logical operation is zero; otherwise Z is cleared.
• OV is set if an operation results in a carry into the highest-order bit but not a carry out of the
highest-order bit, or vice versa; otherwise OV is cleared.
• PDF is cleared by a system power-up or executing the “CLR WDT” instruction. PDF is set by
executing the “HALT” instruction.
• TO is cleared by a system power-up or executing the “CLR WDT” or “HALT” instruction. TO is
set by a WDT time-out.
In addition, on entering an interrupt sequence or executing a subroutine call, the status register will
not be pushed onto the stack automatically. If the contents of the status registers are important and if
the subroutine can corrupt the status register, precautions must be taken to correctly save it.
• 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 5 TO: Watchdog Time-Out flag
0: After power up or executing the “CLR WDT” or “HALT” instruction
1: A watchdog time-out occurred.
Bit 4 PDF: Power down flag
0: After power up or executing the “CLR WDT” instruction
1: By executing the “HALT” instruction
Bit 3 OV: 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 2 Z: 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
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Bit 1 AC: 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 0 C: Carry flag
0: No carry-out
1: An operation results in a carry during an addition operation or if a borrow does
not take place during a subtraction operation
The C flag is also affected by a rotate through carry instruction.
EEPROM Data Memory
This device contains an area of internal EEPROM Data Memory. EEPROM is a non-volatile form
of re-programmable memory, with data retention even when its power supply is removed. By
incorporating this kind of data memory, a whole new host of application possibilities are made
available to the designer. The availability of EEPROM storage allows information such as product
identification numbers, calibration values, specific user data, system setup data or other product
information to be stored directly within the product microcontroller. The process of reading and
writing data to the EEPROM memory has been reduced to a very trivial affair.
EEPROM Data Memory Structure
The EEPROM Data Memory capacity is 128×8 bits for the 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 and Write
operations to the EEPROM are carried out in single byte operations using an address and a 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 way as any
other Special Function Register. The EEC register however, being located in Bank 1, 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.
Bit
Register
Name
7
6
5
4
3
2
1
0
EEA0
EEA
—
EEA6
EEA5
EEA4
EEA3
EEA2
EEA1
EED
D7
D6
D5
D4
D3
D2
D1
D0
EEC
—
—
—
—
WREN
WR
RDEN
RD
EEPROM Register List
• EEA Register
Rev. 1.20
Bit
7
6
5
4
3
2
1
0
Name
—
EEA6
EEA5
EEA4
EEA3
EEA2
EEA1
EEA0
R/W
—
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
—
0
0
0
0
0
0
0
Bit 7
Unimplemented, read as “0”
Bit 6~0
EEA6~EEA0: Data EEPROM address bit 6 ~ bit 0
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• EED Register
Bit
7
6
5
4
3
2
1
0
Name
D7
D6
D5
D4
D3
D2
D1
D0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~0 D7~D0: Data EEPROM data bit 7 ~ bit 0
• 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 3 WREN: Data EEPROM Write Enable
0: Disable
1: Enable
This is the Data EEPROM Write Enable Bit which must be set high before Data
EEPROM write operations are carried out. Clearing this bit to zero will inhibit Data
EEPROM write operations.
Bit 2 WR: EEPROM Write Control
0: Write cycle has finished
1: Activate a write cycle
This is the Data EEPROM Write Control Bit and when set high by the application
program will activate a write cycle. This bit will be automatically reset to zero by the
hardware after the write cycle has finished. Setting this bit high will have no effect if
the WREN has not first been set high.
Bit 1 RDEN: Data EEPROM Read Enable
0: Disable
1: Enable
This is the Data EEPROM Read Enable Bit which must be set high before Data
EEPROM read operations are carried out. Clearing this bit to zero will inhibit Data
EEPROM read operations.
Bit 0 RD: EEPROM Read Control
0: Read cycle has finished
1: Activate a read cycle
This is the Data EEPROM Read Control Bit and when set high by the application
program will activate a read cycle. This bit will be automatically reset to zero by the
hardware after the read cycle has finished. Setting this bit high will have no effect if
the RDEN has not first been set high.
Note: 1. The WREN, WR, RDEN and RD cannot be set high at the same time in one instruction. The
WR and RD cannot be set high at the same time.
2. Ensure that the fSUB clock is stable before executing the write operation.
3. Ensure that the write operation is totally complete before changing the contents of the
EEPROM related registers.
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A/D Flash MCU with EEPROM
Reading Data from the EEPROM
To read data from the EEPROM, the EEPROM address of the data to be read must first be placed in
the EEA register. Then the read enable bit, RDEN, in the EEC register must be set high to enable the
read function. If the RD bit in the EEC register is now set high, a read cycle will be initiated. Setting
the RD bit high will not initiate a read operation if the RDEN bit has not been set. When the read
cycle terminates, the RD bit will be automatically cleared to zero, after which the data can be read
from the EED register. The data will remain in the EED register until another read or write operation
is executed. The application program can poll the RD bit to determine when the data is valid for
reading.
Writing Data to the EEPROM
To write data to the EEPROM, the EEPROM address of the data to be written must first be placed in
the EEA register and the data placed in the EED register. To initiate a write cycle, 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 in two consecutive instruction cycles. The global interrupt bit EMI should also
first be cleared before implementing any write operations, and then set again after the write cycle
has started. Note that setting the WR bit high will not initiate a write cycle if the WREN bit has
not been set. As the EEPROM write cycle is controlled using an internal timer whose operation is
asynchronous to microcontroller system clock, a certain time will elapse before the data will have
been written into the EEPROM. Detecting when the write cycle has finished can be implemented
either by polling the WR bit in the EEC register or by using the EEPROM interrupt. When the write
cycle terminates, the WR bit will be automatically cleared to zero by the microcontroller, informing
the user that the data has been written to the EEPROM. The application program can therefore poll
the WR bit to determine when the write cycle has ended.
Write Protection
Protection against inadvertent write operation is provided in several ways. After the device is
powered-on the Write Enable bit in the control register will be cleared preventing any write
operations. Also at power-on the Bank Pointer register, BP, will be reset to zero, which means that
Data Memory Bank 0 will be selected. As the EEPROM control register is located in Bank 1, this
adds a further measure of protection against spurious write operations. During normal program
operation, ensuring that the Write Enable bit in the control register is cleared will safeguard against
incorrect write operations.
EEPROM Interrupt
The EEPROM write interrupt is generated when an EEPROM write cycle has ended. The EEPROM
interrupt must first be enabled by setting the DEE bit in the relevant interrupt register. However, as
the EEPROM interrupt 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 high. If the global, EEPROM
and multi-function interrupts are enabled and the stack is not full, a jump to the associated Multifunction Interrupt vector will take place. When the interrupt is serviced the Multi-function interrupt
flag will be automatically reset, the EEPROM interrupt flag will be automatically reset.
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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 register, BP, could be normally cleared to zero as this would inhibit access to Bank
1 where the EEPROM control register exists. Although certainly not necessary, consideration might
be given in the application program to the checking of the validity of new write data by a simple
read back process.
When writing data the WR bit must be set high immediately after the WREN bit has been set high,
to ensure the write cycle executes correctly. The global interrupt bit EMI should also be cleared
before a write cycle is executed and then re-enabled after the write cycle starts. Note that the device
should not enter the IDLE or SLEEP mode until the EEPROM read or write operation is totally
complete. Otherwise, the EEPROM read or write operation will fail.
Programming Examples
Reading data from the EEPROM – polling method
MOV A, EEPROM_ADRES
MOV EEA, A
MOV A, 40H
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
; set memory pointer MP1
; MP1 points to EEC register
; set bank pointer BP
; set RDEN bit, enable read operations
; start Read Cycle - set RD bit
; check for read cycle end
; disable EEPROM read if no more read operations are required
; move read data to register
Note: For each read operation, the address register should be re-specified followed by setting the RD
bit high to activate a read cycle even if the target address is consecutive.
Writing Data to the EEPROM – polling method
MOV A, EEPROM_ADRES
MOV EEA, A
MOV A, EEPROM_DATA
MOV EED, A
MOV A, 40H
MOV MP1, A
MOV A, 01H
MOV BP, A
CLR EMI
SET IAR1.3
SET IAR1.2
SET EMI
BACK:
SZ IAR1.2
JMP BACK
CLR BP
Rev. 1.20
; user defined address
; user defined data
; set memory pointer MP1
; MP1 points to EEC register
; set bank pointer BP
; set WREN bit, enable write operations
; start Write Cycle - set WR bit – executed immediately
; after set WREN bit
; check for write cycle end
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Oscillators
Various oscillator options offer the user a wide range of functions according to their various
application requirements. The flexible features of the oscillator functions ensure that the best
optimisation can be achieved in terms of speed and power saving. Oscillator selections and operation
are selected through a combination of configuration options and relevant control registers.
Oscillator Overview
In addition to being the source of the main system clock the oscillators also provide clock sources
for the Watchdog Timer and Time Base Interrupts. External oscillators requiring some external
components as well as fully integrated internal oscillators, requiring no external components, are
provided to form a range of both fast and slow system oscillators. All oscillator type selections
are implemented through configuration options. The higher frequency oscillator provides higher
performance but carry with it the disadvantage of higher power requirements, while the opposite
is of course true for the lower frequency oscillator. With the capability of dynamically switching
between fast and slow system clock, the device has the flexibility to optimize the performance/
power ratio, a feature especially important in power sensitive portable applications.
Name
Frequency
Pins
External High Speed Crystal
Type
HXT
400kHz~16MHz
OSC1/OSC2
Internal High Speed RC
HIRC
8/12/16MHz
—
LXT
32.768kHz
XT1/XT2
LIRC
32kHz
—
External Low Speed Crystal
Internal Low Speed RC
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 the external crystal/ceramic oscillator, HXT, and
the internal 8/12/16MHz RC oscillator, HIRC. The two low speed oscillators are the internal 32kHz
RC oscillator, LIRC, and the external 32.768kHz crystal oscillator, LXT. Selecting whether the low
or high speed oscillator is used as the system oscillator is implemented using the HLCLK bit and
CKS2~CKS0 bits in the SMOD register and the system clock can be dynamically selected.
The actual source clock used for each of the high and low speed oscillators is chosen via
configuration options. The frequency of the slow speed or high speed system clock is also
determined using the HLCLK bit and CKS2~CKS0 bits in the SMOD register. Note that two
oscillator selections must be made namely one high speed and one low speed system oscillators. It is
not possible to choose a no-oscillator selection for either the high or low speed oscillator.
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fH
High Speed
Oscillators
fH/2
fH/4
HXT
HIRC
fH/8
Prescaler
fH
fH/16
fSYS
fH/32
fH/64
Low Speed
Oscillators
LXT
High Speed Oscillator
Configuration Option
HLCLK,
CKS2~CKS0
fSUB
Fast Wake-up from IDLE or
SLEEP Mode Control
(for HXT only )
fSUB
LIRC
Low Speed Oscillator
Configuration Option
System Clock Configurations
External Crystal/Ceramic Oscillator – HXT
The External Crystal/Ceramic System Oscillator is one of the high frequency oscillators. For most
crystal oscillator configurations, the simple connection of a crystal across OSC1 and OSC2 will
create the necessary phase shift and feedback for oscillation, without requiring external capacitors.
However, for some crystal types and frequencies, to ensure oscillation, it may be necessary to add
two small value capacitors, C1 and C2. Using a ceramic resonator will usually require two small
value capacitors, C1 and C2, to be connected as shown for oscillation to occur. The values of C1 and
C2 should be selected in consultation with the crystal or resonator manufacturer’s specification.
For oscillator stability and to minimise the effects of noise and crosstalk, it is important to ensure
that the crystal and any associated resistors and capacitors along with interconnecting lines are all
located as close to the MCU as possible.
C1
Internal
Oscillator
Circuit
OSC1
RP
RF
OSC2
C2
To internal
circuits
Note: 1. RP is normally not required. C1 and C2 are required.
2. Although not shown OSC1/OSC2 pins have a parasitic
capacitance of around 7pF.
Crystal/Resonator Oscillator – HXT
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Crystal Oscillator C1 and C2 Values
Crystal Frequency
C1
C2
16MHz
0pF
0pF
12MHz
0pF
0pF
8MHz
0pF
0pF
6MHz
0pF
0pF
4MHz
0pF
0pF
1MHz
100pF
100pF
Note: C1 and C2 values are for guidance only.
Crystal Recommended Capacitor Values
High Speed Internal RC Oscillator – HIRC
The high speed internal RC oscillator is a fully integrated system oscillator requiring no external
components. The internal RC oscillator has three fixed frequencies of 8MHz, 12MHz and 16MHz,
selected via configuration option. 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. Note that if this internal system clock option is selected, it requires no external pins for
its operation.
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.
The pin-shared software control bits determine if the XT1/XT2 pins are used for the LXT oscillator
or as I/O or other pin-shared functional pins.
• If the LXT oscillator is not used for any clock source, the XT1/XT2 pins can be used as normal I/
O or other pin-shared functional pins.
• If the LXT oscillator is used for any clock source, the 32.768kHz crystal should be connected to
the XT1/XT2 pins.
For oscillator stability and to minimise the effects of noise and crosstalk, it is important to ensure
that the crystal and any associated resistors and capacitors along with interconnecting lines are all
located as close to the MCU as possible.
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A/D Flash MCU with EEPROM
C1
Internal
Oscillator
Circuit
XT1
32.768
kHz
Internal RC
Oscillator
RP
To internal
circuits
XT2
C2
Note: 1. RP, C1 and C2 are required.
2. Although not shown XT1/XT2 pins have a parasitic
capacitance of around 7pF.
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
LXT Oscillator Low Power Function
The LXT oscillator can function in one of two modes, the Quick Start Mode and the Low Power
Mode. The mode selection is executed using the LXTLP bit in the TBC register.
LXTLP
LXT Operating Mode
0
Quick Start
1
Low-Power
After power on, the LXTLP bit will be automatically cleared to zero ensuring that the LXT oscillator
is in the Quick Start operating mode. In the Quick Start Mode the LXT oscillator will power up
and stabilise quickly. However, after the LXT oscillator has fully powered up it can be placed
into the Low-power mode by setting the LXTLP bit high. The oscillator will continue to run but
with reduced current consumption, as the higher current consumption is only required during the
LXT oscillator start-up. In power sensitive applications, such as battery applications, where power
consumption must be kept to a minimum, it is therefore recommended that the application program
sets the LXTLP bit high about 2 seconds after power-on. It should be noted that, no matter what
condition the LXTLP bit is set to, the LXT oscillator will always function normally and the only
difference is that it will take more time to start up if in the Low-power mode.
Internal 32kHz Oscillator – LIRC
The internal 32kHz System Oscillator is one of the low frequency oscillator choices, which is
selected via configuration option. It is a fully integrated RC oscillator with a typical frequency
of 32kHz, requiring no external components for its implementation. Device trimming during the
manufacturing process and the inclusion of internal frequency compensation circuits are used to
ensure that the influence of the power supply voltage, temperature and process variations on the
oscillation frequency are minimised.
Supplementary Oscillators
The low speed oscillators, in addition to providing a system clock source are also used to provide a
clock source to other device functions, such as the Watchdog Timer and the Time Base Interrupts, etc.
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Operating Modes and System Clocks
Present day applications require that their microcontrollers have high performance but often still
demand that they consume as little power as possible, conflicting requirements that are especially
true in battery powered portable applications. The fast clocks required for high performance will
by their nature increase current consumption and of course vice-versa, lower speed clocks reduce
current consumption. As Holtek has provided the device with both high and low speed clock sources
and the means to switch between them dynamically, the user can optimise the operation of their
microcontroller to achieve the best performance/power ratio.
System Clocks
The device has many different clock sources for both the CPU and peripheral function operation.
By providing the user with a wide range of clock selections using configuration options and register
programming, a clock system can be configured to obtain maximum application performance.
The main system clock, can come from either a high frequency fH or low frequency fSUB source, and
is selected using the HLCLK bit and CKS2~CKS0 bits in the SMOD register. The high speed system
clock can be sourced from either an HXT or HIRC oscillator, selected via a configuration option.
The low speed system clock source can be sourced from internal clock fSUB. If fSUB is selected then it
can be sourced by either the LXT or LIRC oscillator, selected via a configuration option. The other
choice, which is a divided version of the high speed system oscillator has a range of fH/2~fH/64.
There are two additional internal clocks for the peripheral circuits, the substitute clock, fSUB, and the
Time Base clock, fTBC. Each of these internal clocks is sourced by either the LXT or LIRC oscillator,
selected via a configuration option. The fSUB clock is used to provide a substitute clock for the
microcontroller just after a wake-up has occurred to enable faster wake-up times.
fH
High Speed
Oscillators
fH/2
fH/4
HXT
HIRC
fH/8
Prescaler
fH
fH/16
fSYS
fH/32
fH/64
Low Speed
Oscillators
LXT
High Speed Oscillator
Configuration Option
Fast Wake-up from IDLE
or SLEEP Mode Control
(for HXT only )
HLCLK,
CKS2~CKS0
fSUB
fSUB
LIRC
fSUB
Low Speed Oscillator
Configuration Option
fSUB
IDLEN
WDT
fTBC
fTBC
fTB
fSYS/4
Time Bases
TBCK
Device Clock Configurations
Note: When the system clock source fSYS is switched to fSUB from fH, the high speed oscillator will be
stopped to conserve the power. Thus there is no fH~fH/64 clock sources for peripheral circuit
to use.
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System Operation Modes
There are six different modes of operation for the microcontroller, each one with its own
special characteristics and which can be chosen according to the specific performance and
power requirements of the application. There are two modes allowing normal operation of the
microcontroller, the NORMAL Mode and SLOW Mode. The remaining four modes, the SLEEP0,
SLEEP1, IDLE0 and IDLE1 Mode, are used when the microcontroller CPU is switched off to
conserve power.
Operation Mode
Description
CPU
fSYS
fSUB
fTBC
NORMAL
On
fH~fH/64
On
On
SLOW
On
fSUB
On
On
IDLE0
Off
Off
On
On
IDLE1
Off
On
On
On
SLEEP0
Off
Off
Off
Off
SLEEP1
Off
Off
On
Off
NORMAL Mode
As the name suggests this is one of the main operating modes where the microcontroller has all of
its functions operational and where the system clock is provided by one of the high speed oscillators.
This mode operates allowing the microcontroller to operate normally with a clock source will come
from one of the high speed oscillators, either the HXT or HIRC oscillator. 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 slow speed oscillators, either the LXT
or LIRC oscillator. Running the microcontroller in this mode allows it to run with much lower
operating current. In the SLOW mode, the fH clock is off.
SLEEP0 Mode
The SLEEP0 Mode is entered when an HALT instruction is executed and when the IDLEN bit in
the SMOD register is low. In the SLEEP0 mode the CPU will be stopped, the fSUB clock will also be
stopped and the Watchdog Timer function is disabled. In this mode, the LVDEN must be cleared to
“0”. If the LVDEN bit is set to “1”, the system will not enter the SLEEP0 Mode.
SLEEP1 Mode
The SLEEP1 Mode is entered when an HALT instruction is executed and when the IDLEN bit in the
SMOD register is low. In the SLEEP1 mode the CPU will be stopped. However the fSUB clock will
continue to operate if the Watchdog Timer function is enabled.
IDLE0 Mode
The IDLE0 Mode is entered when a HALT instruction is executed and when the IDLEN bit in the
SMOD register is high and the FSYSON bit in the CTRL register is low. In the IDLE0 Mode the
system oscillator will be inhibited from driving the CPU but some peripheral functions will remain
operational such as the Watchdog Timer and TMs. In the IDLE0 Mode, the system oscillator will be
stopped.
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IDLE1 Mode
The IDLE1 Mode is entered when an HALT instruction is executed and when the IDLEN bit in the
SMOD register is high and the FSYSON bit in the CTRL register is high. In the IDLE1 Mode the
system oscillator will be inhibited from driving the CPU but may continue to provide a clock source
to keep some peripheral functions operational such as the Watchdog Timer and TMs. In the IDLE1
Mode, the system oscillator will continue to run, and this system oscillator may be a high speed or
low speed system oscillator.
Control Registers
The SMOD register and the FSYSON bit in the CTRL register are 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: System clock selection when HLCLK is “0”
000: fSUB
001: fSUB
010: fH/64
011: fH/32
100: fH/16
101: fH/8
110: fH/4
111: fH/2
These three bits are used to select which clock is used as the system clock source. In
addition to the system clock source, which can be either the LXT or LIRC oscillator,
a divided version of the high speed system oscillator can also be chosen as the system
clock source.
Bit 4 FSTEN: 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 3 LTO: Low speed system oscillator ready flag
0: Not ready
1: Ready
This is the low speed system oscillator ready flag which indicates when the low speed
system oscillator is stable after power on reset or a wake-up has occurred. The flag
will be low when in the SLEEP0 Mode but after a wake-up has occurred, the flag will
change to a high level after 128 clock cycles if the LXT oscillator is used and 1~2
clock cycles if the LIRC oscillator is used.
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Bit 2 HTO: 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 wakeup has occurred, the flag will change to a high level after 128 clock cycles if the HXT
oscillator is used and after 15~16 clock cycles if the HIRC oscillator is used.
Bit 1 IDLEN: 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 IDLE mode the CPU will stop running but
the system clock will continue to keep the peripheral functions operational, if the
FSYSON bit is high. If the FSYSON bit is low, the CPU and the system clock will all
stop in IDLE0 mode. If the bit is low, the device will enter the SLEEP mode when a
HALT instruction is executed.
Bit 0 HLCLK: System clock selection
0: fH/2~fH/64 or fSUB
1: fH
This bit is used to select if the fH clock or the fH/2~fH/64 or fSUB clock is used as
the system clock. When the bit is high the fH clock will be selected and if low the
fH/2~fH/64 or fSUB clock will be selected. When system clock switches from the fH
clock to the fSUB clock and the fH clock will be automatically switched off to conserve
power.
• CTRL Register
Bit
7
6
5
4
Name
FSYSON
R/W
R/W
POR
0
—
3
2
—
—
—
—
—
1
0
—
—
—
—
LVRF
LRF
WRF
R/W
R/W
—
—
R/W
x
0
0
“x”: unknown
Bit 7 FSYSON: fSYS Control in IDLE Mode
0: Disable
1: Enable
This bit is used to control whether the system clock is switched on or not in the IDLE
Mode. If this bit is cleared to “0”, the system clock will be switched off in the IDLE
Mode. However, the system clock will be switched on in the IDLE Mode when the
FSYSON bit is set to “1”.
Bit 6~3
Unimplemented, read as “0”
Bit 2 LVRF: LVR function reset flag
Refer to the Low Voltage Reset section.
Bit 1 LRF: LVR control register software reset flag
Refer to the Low Voltage Reset section.
Bit 0 WRF: WDT control register software reset flag
Refer to the Watchdog Timer Control Register section.
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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, stabilise 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 either the LXT or LIRC oscillator, to act as a temporary clock
to first drive the system until the original system oscillator has stabilised. As the clock source for
the Fast Wake-up function is fSUB, the Fast Wake-up function is only available in the SLEEP1 and
IDLE0 modes. When the device is woken up from the SLEEP0 mode, the Fast Wake-up function has
no effect because the fSUB clock is stopped. The Fast Wake-up enable/disable function is controlled
using the FSTEN bit in the SMOD register.
If the HXT oscillator is selected as the NORMAL Mode system clock, and if the Fast Wake-up
function is enabled, then it will take one to two tSUB clock cycles of the LIRC or LXT oscillator for
the system to wake-up. The system will then initially run under the fSUB clock source until 512 HXT
clock cycles have elapsed, at which point the HTO flag will switch high and the system will switch
over to operating from the HXT oscillator.
If the HIRC oscillator or LIRC oscillator is used as the system oscillator then it will take 15~16
clock cycles of the HIRC or 1~2 cycles of the LIRC to wake up the system from the SLEEP or
IDLE0 Mode. The Fast Wake-up bit, FSTEN will have no effect in these cases.
System
Oscillator
FSTEN
Bit
0
Wake-up Time
(SLEEP0 Mode)
Wake-up Time
(SLEEP1 Mode)
Wake-up Time
(IDLE0 Mode)
Wake-up Time
(IDLE1 Mode)
128 HXT cycles
128 HXT cycles
1
128 HXT cycles
1~2 fSUB cycles
(System runs with fSUB first for 512 HXT
1~2 HXT cycles
cycles and then switches over to run
with the HXT clock)
HIRC
x
15~16 HIRC cycles
15~16 HIRC cycles
1~2 HIRC cycles
LIRC
x
1~2 LIRC cycles
1~2 LIRC cycles
1~2 LIRC cycles
LXT
x
128 LXT cycles
1~2 LXT cycles
1~2 LXT cycles
HXT
Wake-up Times
1~2 HXT cycles
“x”: Don’t care
Note that if the Watchdog Timer is disabled, which means that the LXT and LIRC are both off, then
there will be no Fast Wake-up function available when the device wakes up from the SLEEP0 Mode.
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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
an 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 the FSYSON bit in the
CTRL register.
When the HLCLK bit switches to a low level, which implies that clock source is switched from the
high speed clock, fH, to the clock source, fH/2~fH/64 or fSUB. If the clock is from the fSUB, the high
speed clock source will stop running to conserve power. When this happens, it must be noted that
the fH/16 and fH/64 internal clock sources will also stop running, which may affect the operation of
other internal functions such as the TMs. The accompanying chart shows what happens when the
device moves between the various operating modes.
NORMAL
fSYS=fH~fH/64
fH on
CPU run
fSYS on
fSUB on
fTBC on
SLOW
fSYS=fSUB
fSUB on
CPU run
fSYS on
fH off
fTBC on
SLEEP0
IDLE0
HALT instruction executed
HALT instruction executed
CPU stop
IDLEN=0
fSYS off
fSUB off
CPU stop
IDLEN=1
FSYSON=0
fSYS off
fSUB on
fTBC off
fTBC on
WDT & LVD off
SLEEP1
HALT instruction executed
CPU stop
IDLEN=0
fSYS off
fSUB on
fTBC off
CPU stop
IDLEN=1
FSYSON=1
fSYS on
fSUB on
fTBC on
WDT on
Rev. 1.20
IDLE1
HALT instruction executed
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A/D Flash MCU with EEPROM
NORMAL Mode to SLOW Mode Switching
When running in the NORMAL Mode, which uses the high speed system oscillator, and therefore
consumes more power, the system clock can switch to run in the SLOW Mode by setting the
HLCLK bit to “0” and setting the CKS2~CKS0 bits to “000” or “001” in the SMOD register. This
will then use the low speed system oscillator which will consume less power. Users may decide to
do this for certain operations which do not require high performance and can subsequently reduce
power consumption.
The SLOW Mode system clock is sourced from the LXT or LIRC oscillator determined by the
configuration option and therefore requires the selected oscillator to be stable before full mode
switching occurs. This is monitored using the LTO bit in the SMOD register.
NORMAL Mode
CKS2~CKS0 = 00xB &
HLCLK = 0
SLOW Mode
WDT and LVD are all off
IDLEN=0
HALT instruction is executed
SLEEP0 Mode
WDT is on
IDLEN=0
HALT instruction is executed
SLEEP1 Mode
IDLEN=1, FSYSON=0
HALT instruction is executed
IDLE0 Mode
IDLEN=1, FSYSON=1
HALT instruction is executed
IDLE1 Mode
Rev. 1.20
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A/D Flash MCU with EEPROM
SLOW Mode to NORMAL Mode Switching
In SLOW mode the system uses either the LXT or LIRC low speed system oscillator. To switch
back to the NORMAL Mode, where the high speed system oscillator is used, the HLCLK bit should
be set to “1” or HLCLK bit is “0”, but the CKS2~CKS0 field is set to “010”, “011”, “100”, “101”,
“110” or “111”. As a certain amount of time will be required for 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.
SLOW Mode
CKS2~CKS0 ≠ 000B or 001B
as HLCLK = 0 or HLCLK = 1
NORMAL Mode
WDT and LVD are all off
IDLEN=0
HALT instruction is executed
SLEEP0 Mode
WDT is on
IDLEN=0
HALT instruction is executed
SLEEP1 Mode
IDLEN=1, FSYSON=0
HALT instruction is executed
IDLE0 Mode
IDLEN=1, FSYSON=1
HALT instruction is executed
IDLE1 Mode
Rev. 1.20
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A/D Flash MCU with EEPROM
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 the SMOD register equal to “0” and the
WDT and LVD both off. When this instruction is executed under the conditions described above, the
following will occur:
• The system clock, WDT clock and Time Base clock will be stopped and the application program
will stop at the “HALT” instruction.
• The Data Memory contents and registers will maintain their present condition.
• The WDT will be cleared and stopped no matter if the WDT clock source originates from the
LXT or LIRC oscillator.
• The I/O ports will maintain their present conditions.
• In the status register, the Power Down flag PDF will be set, and WDT timeout flag TO will be
cleared.
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 the SMOD register equal to “0” and the
WDT on. When this instruction is executed under the conditions described above, the following will
occur:
• The system clock and Time Base clock will be stopped and the application program will stop at
the “HALT” instruction, but the WDT will remain with the clock source coming from the fSUB
clock.
• The Data Memory contents and registers will maintain their present condition.
• The WDT will be cleared and resume counting if the WDT function is enabled.
• The I/O ports will maintain their present conditions.
• In the status register, the Power Down flag PDF will be set, and WDT timeout flag TO will be
cleared.
Entering the IDLE0 Mode
There is only one way for the device to enter the IDLE0 Mode and that is to execute the “HALT”
instruction in the application program with the IDLEN bit in the SMOD register equal to “1” and
the FSYSON bit in the CTRL register equal to “0”. When this instruction is executed under the
conditions described above, the following will occur:
• The system clock will be stopped and the application program will stop at the “HALT”
instruction, but the fTBC and fSUB clocks will be on.
• The Data Memory contents and registers will maintain their present condition.
• The WDT will be cleared and resume counting if the WDT function is enabled.
• The I/O ports will maintain their present conditions.
• In the status register, the Power Down flag PDF will be set, and WDT timeout flag TO will be
cleared.
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A/D Flash MCU with EEPROM
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 the SMOD register equal to “1” and
the FSYSON bit in the CTRL register equal to “1”. When this instruction is executed under the
conditions described above, the following will occur:
• The system clock, fTBC and fSUB clocks will be on but the application program will stop at the
“HALT” instruction.
• The Data Memory contents and registers will maintain their present condition.
• The WDT will be cleared and resume counting if the WDT function is enabled.
• The I/O ports will maintain their present conditions.
• In the status register, the Power Down flag PDF will be set, and WDT timeout flag TO will be
cleared.
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. These must either be set as outputs or if set 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 set 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 LXT or LIRC oscillator has enabled via configuration
option.
In the IDLE1 Mode the system oscillator is on, if the peripheral function clock source is derived
from the high speed oscillator, the additional standby current will also be perhaps in the order of
several hundred micro-amps.
Wake-up
To minimise power consumption the device can enter the SLEEP or any IDLE Mode, where the
CPU will be switched off. However, when the device is woken up again, it will take a considerable
time for the original system oscillator to restart, stablise and allow normal operation to resume.
After the system enters the SLEEP or IDLE Mode, it can be woken up from one of various sources
listed as follows:
• An external falling edge on Port A
• A system interrupt
• A WDT overflow
When the device executes the “HALT” instruction, it will enter the IDLE or SLEEP mode and
the PDF flag will be set to 1. The PDF flag will be cleared to 0 if the device experiences a system
power-up or executes the clear Watchdog Timer instruction. If the system is woken up by a WDT
overflow, a Watchdog Timer reset will be initiated and the TO flag will be set to 1. The TO flag is
set if a WDT time-out occurs and causes a wake-up that only resets the Program Counter and Stack
Pointer, other flags remain in their original status.
Rev. 1.20
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A/D Flash MCU with EEPROM
Each pin on Port A can be set 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 high speed and low speed oscillators both use the same SST counter. For example, if the system
is woken up from the SLEEP0 Mode and both the HIRC and LXT oscillators need to start-up from
an off state. The LXT oscillator uses the SST counter after the HIRC oscillator has finished its SST
period.
• If the 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 stability if fSUB is from the 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 the HXT oscillator and FSTEN is “1”, the system clock can be switched to the
LIRC oscillator after wake up.
• There are peripheral functions, such as WDT and TMs, for which the fSYS is used. If the system
clock source is switched from fH to fSUB, the clock source to the peripheral functions mentioned
above will change accordingly.
• The on/off condition of fSUB and fS depends upon whether the WDT is enabled or disabled as the
WDT clock source is selected from fSUB.
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A/D Flash MCU with EEPROM
Watchdog Timer
The Watchdog Timer is provided to prevent program malfunctions or sequences from jumping to
unknown locations, due to certain uncontrollable external events such as electrical noise.
Watchdog Timer Clock Source
The Watchdog Timer clock source is provided by the internal clock, fSUB, which is in turn supplied
by the LIRC or LXT oscillator. The LXT oscillator is supplied by an external 32.768kHz crystal.
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 Watchdog Timer source
clock is then subdivided by a ratio of 28 to 218 to give longer timeouts, the actual value being chosen
using the WS2~WS0 bits in the WDTC register.
Watchdog Timer Control Register
A single register, WDTC, controls the required timeout period as well as the enable/disable
operation. This register controls the overall operation of the Watchdog Timer.
• 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 software control
10101: Disable
01010: Enable
Other values: Reset MCU
When these bits are changed to any other values due to environmental noise the
microcontroller will be reset; this reset operation will be activated after 2~3 LIRC
clock cycles and the WRF bit in the CTRL register will be set high.
Bit 2~0
Rev. 1.20
WS2~WS0: WDT time-out period selection
000: 28/fSUB
001: 210/fSUB
010: 212/fSUB
011: 214/fSUB
100: 215/fSUB
101: 216/fSUB
110: 217/fSUB
111: 218/fSUB
These three bits determine the division ratio of the Watchdog Timer source clock,
which in turn determines the timeout period.
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A/D Flash MCU with EEPROM
• CTRL Register
Bit
7
6
5
4
3
2
1
0
Name
FSYSON
—
—
—
—
LVRF
LRF
WRF
R/W
R/W
—
—
—
—
R/W
R/W
R/W
POR
0
—
—
—
—
x
0
0
“x”: unknown
Bit 7 FSYSON: fSYS Control in IDLE Mode
Refer to the Operating Modes and System Clocks section.
Bit 6~3
Unimplemented, read as “0”
Bit 2 LVRF: LVR function reset flag
Refer to the Low Voltage Reset section.
Bit 1 LRF: LVR control register software reset flag
Refer to the Low Voltage Reset section.
Bit 0 WRF: 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 to zero
by the application program. Note that this bit can only be cleared to zero 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 instruction. If the program malfunctions for whatever reason, jumps
to an unknown location, or enters an endless loop, the clear instruction will not be executed in the
correct manner, in which case the Watchdog Timer will overflow and reset the device. There are five
bits, WE4~WE0, in the WDTC register to offer additional enable/disable 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. The WDT function will be enabled if the WE4~WE0 bits value is 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 LIRC clock cycles. After power on these bits will have the 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 WDTC software reset, which means a certain value except 01010B and 10101B written
into the WE4~WE0 bit filed, the second is using the Watchdog Timer software clear instruction and
the third is via a HALT instruction.
There is only one method of using software instruction to clear the Watchdog Timer. That is to use
the single “CLR WDT” instruction to clear the WDT.
Rev. 1.20
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A/D Flash MCU with EEPROM
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
seconds for the 218 division ratio, and a minimum timeout of 8ms for the 28 division ration.
WDTC WE4~WE0 bits
Register
Reset MCU
CLR
“HALT”Instruction
“CLR WDT”Instruction
fSUB
8-stage Divider
fSUB/28
WDT Prescaler
WS2~WS0
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.
In addition to the power-on reset, another reset exists in the form of a Low Voltage Reset, LVR,
where a full reset is implemented in situations where the power supply voltage falls below a
certain threshold. Another type of reset is when the Watchdog Timer overflows and resets the
microcontroller. All types of reset operations result in different register conditions being setup.
Reset Functions
There are several ways in which a microcontroller reset can occur, each of which will be described
as follows.
Power-on Reset
The most fundamental and unavoidable reset is the one that occurs after power is first applied to
the microcontroller. As well as ensuring that the Program Memory begins execution from the first
memory address, a power-on reset also ensures that certain other registers are preset to known
conditions. All the I/O port and port control registers will power up in a high condition ensuring that
all pins will be first set to inputs.
VDD
Power-on Reset
tRSTD
SST Time-out
Note: tRSTD is power-on delay with typical time=50ms.
Power-On Reset Timing Chart
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Low Voltage Reset – LVR
The microcontroller contains a low voltage reset circuit in order to monitor the supply voltage of the
device and provides an MCU reset should the value fall below a certain predefined level. 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 in battery
powered applications, the LVR will automatically reset the device internally and the LVRF bit in the
CTRL register will also be set high. For a valid LVR signal, a low supply voltage, i.e., a voltage in
the range between 0.9V~VLVR must exist for a time greater than that specified by tLVR in the LVD/
LVR characteristics. If the low supply voltage state does not exceed this value, the LVR will ignore
the low supply voltage and will not perform a reset function. The actual VLVR value can be selected
by the LVS bits in the LVRC register. If the LVS7~LVS0 bits are changed to some different values
by environmental noise, the LVR will reset the device after 2~3 LIRC clock cycles. When this
happens, the LRF bit in the CTRL register will be set high. 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 IDLE or SLEEP mode.
LVR
tRSTD + tSST
Internal Reset
Note: tRSTD is power-on delay with 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 7~0 LVS7~LVS0: LVR voltage selection
01010101: 2.1V
00110011: 2.55V
10011001: 3.15V
10101010: 3.8V
Any other value: 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 the low voltage condition keeps more than a tLVR time. In this
situation the register contents will remain the same after such a reset occurs.
Any register value, other than the four defined LVR values above, will also result in the
generation of an MCU reset. The reset operation will be activated after 2~3 LIRC clock
cycles. However in this situation the register contents will be reset to the POR value.
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A/D Flash MCU with EEPROM
• CTRL Register
Bit
7
6
5
4
3
2
1
0
Name
FSYSON
—
—
—
—
LVRF
LRF
WRF
R/W
R/W
—
—
—
—
R/W
R/W
R/W
POR
0
—
—
—
—
x
0
0
“x”: unknown
Bit 7 FSYSON: fSYS Control in IDLE Mode
Refer to the Operating Modes and System Clocks section.
Bit 6~3
Unimplemented, read as “0”
Bit 2 LVRF: LVR function reset flag
0: Not occur
1: Occurred
This bit is set high when a specific low voltage reset situation condition occurs. This
bit can only be cleared to zero by the application program.
Bit 1 LRF: LVR control register software reset flag
0: Not occur
1: Occurred
This bit is set high if the LVRC register contains any undefined LVR voltage register
values. This in effect acts like a software-reset function. This bit can only be cleared to
zero by the application program.
Bit 0 WRF: WDT control register software reset flag
Refer to the Watchdog Timer Control Register section.
Watchdog Time-out Reset during Normal Operation
The Watchdog time-out Reset during normal operations in the NORMAL or SLOW mode is the
same as the hardware Low Voltage Reset except that the Watchdog time-out flag TO will be set to “1”.
WDT Time-out
tRSTD
Internal Reset
Note: tRSTD is power-on delay with typical time=16.7ms.
WDT Time-out Reset during Normal Operation Timing Chart
Watchdog Time-out Reset during SLEEP or IDLE Mode
The Watchdog time-out Reset during SLEEP or IDLE Mode is a little different from other kinds
of reset. Most of the conditions remain unchanged except that the Program Counter and the Stack
Pointer will be cleared to “0” and the TO flag will be set to “1”. Refer to the A.C. Characteristics for
tSST details.
WDT Time-out
tSST
Internal Reset
WDT Time-out Reset during SLEEP or IDLE Timing Chart
Rev. 1.20
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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
Note: "u" stands for unchanged
The following table indicates the way in which the various components of the microcontroller are
affected after a power-on reset occurs.
Item
Condition after Reset
Program Counter
Reset to zero
Interrupts
All interrupts will be disabled
WDT, Time Bases
Cleared after reset, WDT begins counting
Timer Modules
Timer Module will be turned off
Input/Output Ports
I/O ports will be set as inputs
Stack Pointer
Stack Pointer will point to the top of the stack
The different kinds of resets all affect the internal registers of the microcontroller in different ways.
To ensure reliable continuation of normal program execution after a reset occurs, it is important to
know what condition the microcontroller is in after a particular reset occurs. The following table
describes how each type of reset affects each of the microcontroller internal registers. Note that as
more than one package type exists, the table will reflect the situation for the larger package type.
Reset
(Power On)
LVR Reset
(Normal Operation)
WDT Time-out
(Normal Operation)
WDT Time-out
(IDLE or SLEEP)
IAR0
xxxx xxxx
uuuu uuuu
xxxx xxxx
uuuu uuuu
MP0
xxxx xxxx
xxxx xxxx
xxxx xxxx
uuuu uuuu
IAR1
xxxx xxxx
uuuu uuuu
xxxx xxxx
uuuu uuuu
MP1
xxxx xxxx
xxxx xxxx
xxxx xxxx
uuuu uuuu
BP
---- --00
---- --00
---- --00
---- --uu
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
---x xxxx
---u uuuu
---u uuuu
---u uuuu
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
INTC0
-000 0000
-000 0000
-000 0000
-uuu uuuu
INTC1
0000 0000
0000 0000
0000 0000
uuuu uuuu
INTC2
0000 0000
0000 0000
0000 0000
uuuu uuuu
MFI0
--00 --00
--00 --00
--00 --00
--uu --uu
MFI1
0000 0000
0000 0000
0000 0000
uuuu uuuu
MFI2
--00 --00
--00 --00
--00 --00
--uu --uu
Register
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A/D Flash MCU with EEPROM
Reset
(Power On)
LVR Reset
(Normal Operation)
WDT Time-out
(Normal Operation)
WDT Time-out
(IDLE or SLEEP)
PA
1111 1111
1111 1111
1111 1111
uuuu uuuu
PAC
1111 1111
1111 1111
1111 1111
uuuu uuuu
PAPU
0000 0000
0000 0000
0000 0000
uuuu uuuu
PAWU
0000 0000
0000 0000
0000 0000
uuuu uuuu
ACERH
---- 0000
---- 0000
---- 0000
---- uuuu
TMPC
0--- -000
0--- -000
0--- -000
u--- -uuu
WDTC
0 1 0 1 0 0 11
0 1 0 1 0 0 11
0 1 0 1 0 0 11
uuuu uuuu
TBC
0 0 11 0 111
0 0 11 0 111
0 0 11 0 111
uuuu uuuu
CTRL
0--- -x00
0--- -000
0--- -uuu
u--- -uuu
LVRC
0101 0101
uuuu uuuu
0101 0101
uuuu uuuu
EEA
-000 0000
-000 0000
-000 0000
-uuu uuuu
EED
0000 0000
0000 0000
0000 0000
uuuu uuuu
Register
SADOL
Rev. 1.20
xxxx ----
xxxx ----
xxxx ----
uuuu ---(ADRFS=0)
uuuu uuuu
(ADRFS=1)
uuuu uuuu
(ADRFS=0)
SADOH
xxxx xxxx
uuuu uuuu
uuuu uuuu
SADC0
0000 0000
0000 0000
0000 0000
uuuu uuuu
SADC1
000- -000
000- -000
000- -000
uuu- -uuu
SADC2
0000 0000
0000 0000
0000 0000
uuuu uuuu
PB
- 111 1111
- 111 1111
- 111 1111
-uuu uuuu
PBC
- 111 1111
- 111 1111
- 111 1111
-uuu uuuu
PBPU
-000 0000
-000 0000
-000 0000
-uuu uuuu
CTMC0
0000 0---
0000 0---
0000 0---
uuuu u---
CTMC1
0000 0000
0000 0000
0000 0000
uuuu uuuu
CTMDL
0000 0000
0000 0000
0000 0000
uuuu uuuu
CTMDH
0000 0000
0000 0000
0000 0000
uuuu uuuu
CTMAL
0000 0000
0000 0000
0000 0000
uuuu uuuu
CTMAH
0000 0000
0000 0000
0000 0000
uuuu uuuu
CTMRP
0000 0000
0000 0000
0000 0000
uuuu uuuu
STMC0
0000 0---
0000 0---
0000 0---
uuuu u---
STMC1
0000 0000
0000 0000
0000 0000
uuuu uuuu
STMDL
0000 0000
0000 0000
0000 0000
uuuu uuuu
STMDH
0000 0000
0000 0000
0000 0000
uuuu uuuu
STMAL
0000 0000
0000 0000
0000 0000
uuuu uuuu
STMAH
0000 0000
0000 0000
0000 0000
uuuu uuuu
STMRP
0000 0000
0000 0000
0000 0000
uuuu uuuu
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
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
55
---- uuuu
(ADRFS=1)
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HT66F0195
A/D Flash MCU with EEPROM
Reset
(Power On)
LVR Reset
(Normal Operation)
WDT Time-out
(Normal Operation)
WDT Time-out
(IDLE or SLEEP)
CPC
1000 0001
1000 0001
1000 0001
uuuu uuuu
PC
- 111 1111
- 111 1111
- 111 1111
-uuu uuuu
PCC
- 111 1111
- 111 1111
- 111 1111
-uuu uuuu
PCPU
-000 0000
-000 0000
-000 0000
-uuu uuuu
ACERL
0000 0000
0000 0000
0000 0000
uuuu uuuu
SIMC0
111 - 0 0 0 0
111 - 0 0 0 0
111 - 0 0 0 0
uuu- uuuu
SIMC1
1000 0001
1000 0001
1000 0001
uuuu uuuu
SIMD
xxxx xxxx
xxxx xxxx
xxxx xxxx
uuuu uuuu
SIMA/SIMC2
0000 0000
0000 0000
0000 0000
uuuu uuuu
SIMTOC
0000 0000
0000 0000
0000 0000
uuuu uuuu
SLCDC0
0000 0000
0000 0000
0000 0000
uuuu uuuu
SLCDC1
0000 0000
0000 0000
0000 0000
uuuu uuuu
SLCDC2
0000 0000
0000 0000
0000 0000
uuuu uuuu
SLCDC3
0000 0000
0000 0000
0000 0000
uuuu uuuu
SLCDC4
---- --00
---- --00
---- --00
---- --uu
SLEDC0
0101 0101
0101 0101
0101 0101
uuuu uuuu
SLEDC1
--01 0101
--01 0101
--01 0101
--uu uuuu
IFS
0000 0000
0000 0000
0000 0000
uuuu uuuu
PD
- - - - 1111
- - - - 1111
- - - - 1111
---- uuuu
PDC
- - - - 1111
- - - - 1111
- - - - 1111
---- uuuu
PDPU
---- 0000
---- 0000
---- 0000
---- uuuu
USR
0 0 0 0 1 0 11
0 0 0 0 1 0 11
0 0 0 0 1 0 11
uuuu uuuu
UCR1
0000 00x0
0000 00x0
0000 00x0
uuuu uuuu
UCR2
0000 0000
0000 0000
0000 0000
uuuu uuuu
BRG
xxxx xxxx
xxxx xxxx
xxxx xxxx
uuuu uuuu
TXR_RXR
xxxx xxxx
xxxx xxxx
xxxx xxxx
uuuu uuuu
EEC
---- 0000
---- 0000
---- 0000
---- uuuu
Register
Note: “u” stands for unchanged
“x” stands for unknown
“-” stands for unimplemented
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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 name PA~PD. These I/O ports
are mapped to the RAM Data Memory with specific addresses as shown in the Special Purpose
Data Memory table. All of these I/O ports can be used for input and output operations. For input
operation, these ports are non-latching, which means the inputs must be ready at the T2 rising edge
of instruction “MOV A, [m]”, where m denotes the port address. For output operation, all the data is
latched and remains unchanged until the output latch is rewritten.
Bit
Register
Name
7
6
5
4
3
2
1
0
PA
PA7
PA6
PA5
PA4
PA3
PA2
PA1
PA0
PAC
PAC7
PAC6
PAC5
PAC4
PAC3
PAC2
PAC1
PAC0
PAPU
PAPU7
PAPU6
PAPU5
PAPU4
PAPU3
PAPU2
PAPU1
PAPU0
PAWU
PAWU7
PAWU6
PAWU5
PAWU4
PAWU3
PAWU2
PAWU1
PAWU0
PB
—
PB6
PB5
PB4
PB3
PB2
PB1
PB0
PBC
—
PBC6
PBC5
PBC4
PBC3
PBC2
PBC1
PBC0
PBPU
—
PBPU6
PBPU5
PBPU4
PBPU3
PBPU2
PBPU1
PBPU0
PC
—
PC6
PC5
PC4
PC3
PC2
PC1
PC0
PCC
—
PCC6
PCC5
PCC4
PCC3
PCC2
PCC1
PCC0
PCPU
—
PCPU6
PCPU5
PCPU4
PCPU3
PCPU2
PCPU1
PCPU0
PD
—
—
—
—
PD3
PCD2
PD1
PD0
PDC
—
—
—
—
PDC3
PDC2
PDC1
PDC0
PDPU
—
—
—
—
PDPU3
PDPU2
PDPU1
PDPU0
I/O Logic Function Register List
“—”: Unimplemented, read as “0”
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, except the SCS input, have the capability of being connected to an internal
pull-high resistor. These pull-high resistors are selected using the relevant pull-high control registers
PAPU~PDPU, and are implemented using weak PMOS transistors.
• PxPU Register
Bit
7
6
5
4
3
2
1
0
Name
PxPU7
PxPU6
PxPU5
PxPU4
PxPU3
PxPU2
PxPU1
PxPU0
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
PxPUn: I/O Port x Pin pull-high function control
0: Disable
1: Enable
The PxPUn bit is used to control the pin pull-high function. Here the “x” can be A, B, C or D.
However, the actual available bits for each I/O Port may be different.
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A/D Flash MCU with EEPROM
Port A Wake-up
The HALT instruction forces the microcontroller into the SLEEP or IDLE Mode which preserves
power, a feature that is important for battery and other low-power applications. Various methods
exist to wake-up the microcontroller, one of which is to change the logic condition on one of the Port
A pins from high to low. This function is especially suitable for applications that can be woken up
via external switches. Each pin on Port A can be selected individually to have this wake-up feature
using the PAWU register.
• PAWU Register
Bit
7
6
5
4
3
2
1
0
Name
PAWU7
PAWU6
PAWU5
PAWU4
PAWU3
PAWU2
PAWU1
PAWU0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~0
PAWU7~PAWU0: PA7~PA0 wake-up function control
0: Disable
1: Enable
I/O Port Control Registers
Each I/O port has its own control register known as PAC~PDC, to control the input/output
configuration. With this control register, each CMOS output or input can be reconfigured
dynamically under software control. Each pin of the I/O ports is directly mapped to a bit in its
associated port control register. For the I/O pin to function as an input, the corresponding bit of the
control register must be written as a “1”. This will then allow the logic state of the input pin to be
directly read by instructions. When the corresponding bit of the control register is written as a “0”,
the I/O pin will be set as a CMOS output. If the pin is currently set 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.
• PxC Register
Bit
7
6
5
4
3
2
1
0
Name
PxC7
PxC6
PxC5
PxC4
PxC3
PxC2
PxC1
PxC0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
1
1
1
1
1
1
1
1
PxCn: I/O Port x Pin type selection
0: Output
1: Input
The PxCn bit is used to control the pin type selection. Here the “x” can be A, B, C or D.
However, the actual available bits for each I/O Port may be different.
I/O Port Source Current Control
This device supports different source current driving capability for each I/O port. With the
corresponding selection register, SLEDC0 and SLEDC1, each I/O port can support four levels of the
source current driving capability. Users should refer to the D.C. Characteristics section to select the
desired source current for different applications.
Bit
Register
Name
7
6
5
4
3
2
1
0
SLEDC0
PBPS3
PBPS2
PBPS1
PBPS0
PAPS3
PAPS2
PAPS1
PAPS0
SLEDC1
—
—
PDPS1
PDPS0
PCPS3
PCPS2
PCPS1
PCPS0
I/O Port Source Current Selection Register List
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A/D Flash MCU with EEPROM
• SLEDC0 Register
Bit
7
6
5
4
3
2
1
0
Name
PBPS3
PBPS2
PBPS1
PBPS0
PAPS3
PAPS2
PAPS1
PAPS0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
1
0
1
0
1
0
1
Bit 7~6 PBPS3~PBPS2: PB6~PB4 source current selection
00: Source current=Level 0 (Min.)
01: Source current=Level 1
10: Source current=Level 2
11: Source current=Level 3 (Max.)
Bit 5~4
PBPS1~PBPS0: PB3~PB0 source current selection
00: Source current=Level 0 (Min.)
01: Source current=Level 1
10: Source current=Level 2
11: Source current=Level 3 (Max.)
Bit 3~2
PAPS3~PAPS2: PA7~PA4 source current selection
00: Source current=Level 0 (Min.)
01: Source current=Level 1
10: Source current=Level 2
11: Source current=Level 3 (Max.)
Bit 1~0
PAPS1~PAPS0: PA3~PA0 source current selection
00: Source current=Level 0 (Min.)
01: Source current=Level 1
10: Source current=Level 2
11: Source current=Level 3 (Max.)
• SLEDC1 Register
Bit
Rev. 1.20
7
6
5
4
3
2
1
0
Name
—
—
PDPS1
PDPS0
PCPS3
PCPS2
PCPS1
PCPS0
R/W
—
—
R/W
R/W
R/W
R/W
R/W
R/W
POR
—
—
0
1
0
1
0
1
Bit 7~6
Unimplemented, read as “0”
Bit 5~4
PDPS1~PDPS0: PD3~PD0 source current selection
00: Source current=Level 0 (Min.)
01: Source current=Level 1
10: Source current=Level 2
11: Source current=Level 3 (Max.)
Bit 3~2
PCPS3~PCPS2: PC6~PC4 source current selection
00: Source current=Level 0 (Min.)
01: Source current=Level 1
10: Source current=Level 2
11: Source current=Level 3 (Max.)
Bit 1~0
PCPS1~PCPS0: PC3~PC0 source current selection
00: Source current=Level 0 (Min.)
01: Source current=Level 1
10: Source current=Level 2
11: Source current=Level 3 (Max.)
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Pin-remapping Functions
The flexibility of the microcontroller range is greatly enhanced by the use of pins that have more
than one function. Limited numbers of pins can force serious design constraints on designers but
by supplying pins with multi-functions, many of these difficulties can be overcome. The way in
which the pin function of each pin is selected is different for each function and a priority order is
established where more than one pin function is selected simultaneously. Additionally there is a
register, IFS, to establish certain pin functions.
The limited number of supplied pins in a package can impose restrictions on the amount of functions
a certain device can contain. However by allowing the same pins to share several different functions
and providing a means of function selection, a wide range of different functions can be incorporated
into even relatively small package sizes. If the pin-shared pin function have multiple outputs
simultaneously, its pin names at the right side of the “/” sign can be used for higher priority.
• IFS Register
Bit
Name
Rev. 1.20
7
6
5
4
RXCTL SDOPS1 SDOPS0
SDI_SDAPS
3
2
1
0
SCK_SCLPS SCSBPS TXPS RXPS
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
RXCTL: RX enable control
0: Disable
1: Enable
Bit 6~5
SDOPS1~SDOPS0: SDO pin-remapping selection
00: SDO on PC3
01: SDO on PA1
10: Undefined
11: SDO on PC2
Bit 4
SDI_SDAPS: SDI/SDA pin-remapping selection
0: SDI/SDA on PC4
1: SDI/SDA on PA3
Bit 3
SCK_SCLPS: SCK/SCL pin-remapping selection
0: SCK/SCL on PC5
1: SCK/SCL on PB6
Bit 2
SCSBPS: SCS pin-remapping selection
0: SCS on PC6
1: SCS on PB5
Bit 1
TXPS: TX pin-remapping selection
0: TX on PD2
1: TX on PB3
Bit 0
RXPS: RX pin-remapping selection
0: RX on PD1
1: RX on PB4
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I/O Pin Structures
The accompanying diagram illustrates the internal structure of the I/O logic function. As the exact
logical construction of the I/O pin will differ from this drawing, it is supplied as a guide only to
assist with the functional understanding of the I/O logic function. The wide range of pin-shared
structures does not permit all types to be shown.
VDD
Control Bit
Data Bus
Write Control Register
Chip Reset
Read Control Register
D
Q
Weak
Pull-up
CK Q
S
I/O pin
Data Bit
D
Write Data Register
Pull-high
Register
Select
Q
CK Q
S
Read Data Register
System Wake-up
M
U
X
wake-up Select
PA only
Logic Function Input/Output Structure
Programming Considerations
Within the user program, one of the first things to consider is port initialisation. After a reset, all
of the I/O data and port control registers will be set high. This means that all I/O pins will default
to an input state, the level of which depends on the other connected circuitry and whether pullhigh selections have been chosen. If the port control registers are then programmed to set 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 set to have this
function.
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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 this device includes a Timer Module, abbreviated
to the name TM. The TM is a multi-purpose timing unit and serves to provide operations such as
Timer/Counter, Compare Match Output as well as being the functional unit for the generation of
PWM signals. The TM has two individual interrupts. The addition of input and output pins for the
TM ensures that users are provided with timing units with a wide and flexible range of features.
The common features of the different TM types are described here with more detailed information
provided in the individual Compact, Standard and Periodic TM sections.
Introduction
The device contains three TMs and each individual TM can be categorised as a certain type, namely
Compact Type TM, Standard Type TM or Periodic Type TM. Although similar in nature, the
different TM types vary in their feature complexity. The common features to all of the Compact,
Standard and Periodic TMs will be described in this section and the detailed operation regarding
each of the TM types will be described in separate sections. The main features and differences
between the three types of TMs are summarised in the accompanying table.
CTM
STM
PTM
Timer/Counter
TM Function
√
√
√
Input Capture
—
√
√
Compare Match Output
√
√
√
PWM Channels
1
1
1
Single Pulse Output
—
1
1
Edge
Edge
Edge
Duty or Period
Duty or Period
Duty or Period
PWM Alignment
PWM Adjustment Period & Duty
TM Function Summary
TM Operation
The different types of TM offer a diverse range of functions, from simple timing operations to PWM
signal generation. The key to understanding how the TM operates is to see it in terms of a free
running count-up counter whose value is then compared with the value of pre-programmed internal
comparators. When the free running count-up counter has the same value as the pre-programmed
comparator, known as a compare match situation, a TM interrupt signal will be generated which
can clear the counter and perhaps also change the condition of the TM output pin. The internal TM
counter is driven by a user selectable clock source, which can be an internal clock or an external pin.
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” stands for C, S or P type TM. 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 for event counting.
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TM Interrupts
The Compact Type, Standard Type 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. 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 xTM
input pin, xTCK, is essentially a clock source for the xTM 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. The xTCK input pin can be chosen to have either a rising or falling active edge. The
STCK and PTCK pins are also used as the external trigger input pin in single pulse output mode for
the STM and PTM respectively.
The TMs each have one output pin, 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. The xTP pin acts as an input when the TM is setup to operate in the Capture Input Mode.
As the xTP pins are pin-shared with other functions, the xTP pin function is enabled or disabled
according to the internal TM on/off control, operation mode and output control settings. When the
corresponding TM configuration selects the xTP pin to be used as an output pin, the associated pin
will be setup as an external TM output pin. If the TM configuration selects the xTP pin to be setup as
an input pin, the input signal supplied on the associated pin can be derived from an external signal
and other pin-shared output function. If the TM configuration determines that the xTP pin function
is not used, the associated pin will be controlled by other pin-shared functions. The details of the
external pins for each TM type and device are provided in the accompanying table.
STM
PTM
CTM
Register
STCK0; STP
PTCK; PTP
CTCK; CTP
xTMC0; TMPC
TM External Pins
TM Input/Output Pin Control Register
Selecting to have a TM input/output or whether to retain its other shared function is implemented
using one register, with a single bit in the register corresponding to a TM input/output pin. Setting
the bit high will setup the corresponding pin as a TM input/output, if reset to zero the pin will return
its original other functions.
PA0 Output Function
0
1
PA0/STP
0
Output
1
STM
T0CP
PA0
Capture Input
TCK Input
PB2/STCK
STM Function Pin Control Block Diagram
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A/D Flash MCU with EEPROM
PA7 Output Function
0
PA7/PTP
1
0
Output
1
T1CP
PA7
PTM
Capture Input
0
1
T1CAPTS
TCK Input
PA4/PTCK
PTM Function Pin Control Block Diagram
0
PB3 Output Function
PB3/CTP
1
0
Output
CTM
1
T2CP
PB3
CTCK Input
PA6/CTCK
CTM Function Pin Control Block Diagram
Note: 1. The I/O register data bits shown are used for TM output inversion control.
2. In the Capture Input Mode, the TM pin control register must never enable more than one
TM input.
• TMPC Register
Bit
7
6
5
4
3
2
1
0
Name
CLOP
—
—
—
—
T2CP
T1CP
T0CP
R/W
R/W
—
—
—
—
R/W
R/W
R/W
POR
0
—
—
—
—
0
0
0
Bit 7
Rev. 1.20
CLOP: CLO pin control
0: Disable
1: Enable
Bit 6~3
Unimplemented, read as “0”
Bit 2
T2CP: CTP pin control
0: Disable
1: Enable
Bit 1
T1CP: PTP pin control
0: Disable
1: Enable
Bit 0
T0CP: STP pin control
0: Disable
1: Enable
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Programming Considerations
The TM Counter Registers and the Capture/Compare CCRA and CCRP registers, all have a low
and high byte structure. The high bytes can be directly accessed, but as the low bytes can only be
accessed via an internal 8-bit buffer, reading or writing to these register pairs must be carried out in
a specific way. The important point to note is that data transfer to and from the 8-bit buffer and its
related low byte only takes place when a write or read operation to its corresponding high byte is
executed.
As the CCRA and CCRP registers are implemented in the way shown in the following diagram and
accessing these register pairs is carried out in a specific way as described above, it is recommended
to use the “MOV” instruction to access the CCRA and CCRP low byte registers, named xTMAL and
PTMRPL, using the following access procedures. Accessing the CCRA or CCRP low byte registers
without following these access procedures will result in unpredictable values.
xTM Counter Register (Read only)
xTMDL
xTMDH
8-bit Buffer
xTMAL
xTMAH
xTM CCRA Register (Read/Write)
PTMRPL
PTMRPH
PTM CCRP Register (Read/Write)
Data Bus
The following steps show the read and write procedures:
• Writing Data to CCRA or CCRP
♦
Step 1. Write data to Low Byte xTMAL or PTMRPL
– Note that here data is only written to the 8-bit buffer.
♦
Step 2. Write data to High Byte xTMAH or PTMRPH
– Here data is written directly to the high byte registers and simultaneously data is latched
from the 8-bit buffer to the Low Byte registers.
• Reading Data from the Counter Registers and CCRA or CCRP
Rev. 1.20
♦
Step 1. Read data from the High Byte xTMDH, xTMAH or PTMRPH
– Here data is read directly from the High Byte registers and simultaneously data is latched
from the Low Byte register into the 8-bit buffer.
♦
Step 2. Read data from the Low Byte xTMDL, xTMAL or PTMRPL
– This step reads data from the 8-bit buffer.
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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 pin.
CTM Core
CTM Input Pin
CTM Output Pin
16-bit CTM
CTCK
CTP
CCRP
8-bit Comparator P
fSYS/4
000
fSYS
001
fH/16
010
fH/64
011
fSUB
100
fSUB
101
110
CTCK
111
Comparator P Match
CTMPF Interrupt
CTOC
b8~b15
16-bit Count-up Counter
CTON
CTPAU
Counter Clear
CTCCLR
b0~b15
16-bit Comparator A
0
1
Comparator A Match
Output
Control
Polarity
Control
Pin Control
CTM1, CTM0
CTIO1, CTIO0
CTPOL
T2CP
CTP
CTMAF Interrupt
CTCK2~CTCK0
CCRA
16-bit Compact Type TM Block Diagram
Compact Type TM Operation
At its core is a 16-bit count-up counter which is driven by a user selectable internal or external clock
source. There are also two internal comparators with the names, Comparator A and Comparator
P. These comparators will compare the value in the counter with CCRP and CCRA registers. The
CCRP is 8-bit wide whose value is compared with the highest eight bits in the counter while the
CCRA is 16-bit wide and therefore compares with all counter bits.
The only way of changing the value of the 16-bit counter using the application program, is to
clear the counter by changing the 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 CTM 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 the output pin. All operating setup conditions are
selected using relevant internal registers.
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Compact Type TM Register Description
Overall operation of the Compact TM is controlled using a series of registers. A read only register
pair exists to store the internal counter 16-bit value, while a read/write register pair exists to store
the internal 16-bit CCRA value. The CTMRP register is used to store the 8-bit CCRP value. The
remaining two registers are control registers which setup the different operating and control modes.
Bit
Register
Name
7
6
5
4
3
2
1
0
CTMC0
CTPAU
CTCK2
CTCK1
CTCK0
CTON
—
—
—
CTMC1
CTM1
CTM0
CTIO1
CTIO0
CTOC
CTPOL
CTDPX
CTCCLR
CTMDL
D7
D6
D5
D4
D3
D2
D1
D0
CTMDH
D15
D14
D13
D12
D11
D10
D9
D8
CTMAL
D7
D6
D5
D4
D3
D2
D1
D0
CTMAH
D15
D14
D13
D12
D11
D10
D9
D8
CTMRP
CTRP7
CTRP6
CTRP5
CTRP4
CTRP3
CTRP2
CTRP1
CTRP0
16-bit Compact TM Register List
• CTMC0 Register
Bit
7
6
5
4
3
2
1
0
Name
CTPAU
CTCK2
CTCK1
CTCK0
CTON
—
—
—
R/W
R/W
R/W
R/W
R/W
R/W
—
—
—
POR
0
0
0
0
0
—
—
—
Bit 7 CTPAU: 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 CTM 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: CTM counter clock selection
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 CTM. 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 3 CTON: CTM counter on/off control
0: Off
1: On
This bit controls the overall on/off function of the CTM. Setting the bit high enables
the counter to run while clearing the bit disables the CTM. Clearing this bit to zero
will stop the counter from counting and turn off the CTM 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 CTM is in
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the Compare Match Output Mode or the PWM Output Mode then the CTM 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 2~0
Unimplemented, read as “0”
• CTMC1 Register
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: CTM operating mode selection
00: Compare Match Output Mode
01: Undefined
10: PWM Output Mode
11: Timer/Counter Mode
These bits set the required operating mode for the CTM. To ensure reliable operation
the CTM should be switched off before any changes are made to the CTM1 and CTM0
bits. In the Timer/Counter Mode, the CTM output pin control must be disabled.
Bit 5~4 CTIO1~CTIO0: CTM output function selection
Compare Match Output Mode
00: No change
01: Output low
10: Output high
11: Toggle output
PWM Output Mode
00: PWM output inactive state
01: PWM output active state
10: PWM output
11: Undefined
Timer/Counter Mode
Unused
These two bits are used to determine how the CTM output pin changes state when a
certain condition is reached. The function that these bits select depends upon in which
mode the CTM is running.
In the Compare Match Output Mode, the CTIO1 and CTIO0 bits determine how the
CTM output pin changes state when a compare match occurs from the Comparator A.
The CTM output pin can be set 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 CTM output pin
should be configured 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 CTM output pin when
a compare match occurs. After the CTM 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 Output Mode, the CTIO1 and CTIO0 bits determine how the CTM
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 CTM has been switched off.
Unpredictable PWM outputs will occur if the CTIO1 and CTIO0 bits are changed
when the CTM is running.
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Bit 3 CTOC: CTM CTP output control
Compare Match Output Mode
0: Initial low
1: Initial high
PWM Output Mode
0: Active low
1: Active high
This is the output control bit for the CTM output pin. Its operation depends upon
whether CTM is being used in the Compare Match Output Mode or in the PWM
Output Mode. It has no effect if the CTM is in the Timer/Counter Mode. In the
Compare Match Output Mode it determines the logic level of the CTM output pin
before a compare match occurs. In the PWM Output Mode it determines if the PWM
signal is active high or active low.
Bit 2 CTPOL: CTM 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 CTM
output pin will be inverted and not inverted when the bit is zero. It has no effect if the
CTM is in the Timer/Counter Mode.
Bit 1 CTDPX: CTM PWM duty/period control
0: CCRP – period; CCRA – duty
1: CCRP – duty; CCRA – period
This bit determines which of the CCRA and CCRP registers are used for period and
duty control of the PWM waveform.
Bit 0 CTCCLR: CTM counter clear condition selection
0: CTM Comparator P match
1: CTM Comparator A match
This bit is used to select the method which clears the counter. Remember that the
Compact TM contains two comparators, Comparator A and Comparator P, either of
which can be selected to clear the internal counter. With the 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 Output Mode.
• 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
D7~D0: CTM Counter Low Byte Register bit 7 ~ bit 0
CTM 16-bit Counter bit 7 ~ bit 0
• CTMDH Register
Bit
7
6
5
4
3
2
1
0
Name
D15
D14
D13
D12
D11
D10
D9
D8
R/W
R
R
R
R
R
R
R
R
POR
0
0
0
0
0
0
0
0
Bit 7~0 D15~D8: CTM Counter High Byte Register bit 7 ~ bit 0
CTM 16-bit Counter bit 15 ~ bit 8
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• CTMAL 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
2
1
0
Bit 7~0
D7~D0: CTM CCRA Low Byte Register bit 7 ~ bit 0
CTM 16-bit CCRA bit 7 ~ bit 0
• CTMAH Register
Bit
7
6
5
4
3
Name
D15
D14
D13
D12
D11
D10
D9
D8
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~0 D15~D8: CTM CCRA High Byte Register bit 7 ~ bit 0
CTM 16-bit CCRA bit 15 ~ bit 8
• CTMRP Register
Bit
7
6
5
4
3
2
1
0
Name
CTRP7
CTRP6
CTRP5
CTRP4
CTRP3
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 7~0
CTRP7~CTRP0: CTM CCRP 8-bit register, compared with the CTM Counter bit 15 ~ bit 8
Comparator P Match Period =
0: 65536 CTM clocks
1~255: 256 × (1~255) CTM clocks
These eight bits are used to setup the value on the internal CCRP 8-bit register, which
are then compared with the internal counter’s highest eight bits. The result of this
comparison can be selected to clear the internal counter if the 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 eight counter bits, the compare values exist in 256 clock cycle multiples.
Clearing all eight bits to zero is in effect allowing the counter to overflow at its
maximum value.
Compact Type TM Operating Modes
The Compact Type TM can operate in one of three operating modes, Compare Match Output Mode,
PWM Output 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
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CTCCLR is high no CTMPF interrupt request flag will be generated. If the CCRA bits are all zero,
the counter will overflow when it reaches its maximum 16-bit, FFFF 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 CTM output pin will change
state. The CTM 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 CTM
output pin. The way in which the CTM output pin changes state are determined by the condition of
the CTIO1 and CTIO0 bits in the CTMC1 register. The CTM 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 CTM output pin, which is setup after
the CTON 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.
Counter overflow
Counter Value
CCRP > 0
Counter cleared by CCRP value
CCRP=0
0xFFFF
CCRP > 0
CTCCLR = 0; CTM [1:0] = 00
Counter
Restart
Resume
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 not affected by
CTMAF flag. Remains High
until reset by CTON bit
Output Toggle with
CTMAF flag
Here CTIO [1:0] = 11
Toggle Output select
Note CTIO [1:0] = 10
Active High Output select
Output Inverts
when CTPOL is high
Output Pin
Reset to Initial value
Output controlled by
other pin-shared function
Compare Match Output Mode – CTCCLR=0
Note: 1. With CTCCLR=0, a Comparator P match will clear the counter
2. The CTM 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
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Counter Value
CTCCLR = 1; CTM [1:0] = 00
CCRA = 0
Counter overflow
CCRA > 0 Counter cleared by CCRA value
0xFFFF
CCRA=0
Resume
CCRA
Pause
Stop
Counter Restart
CCRP
Time
CTON
CTPAU
CTPOL
No CTMAF flag
generated on
CCRA overflow
CCRA Int.
flag CTMAF
CCRP Int.
flag CTMPF
CTMPF not
generated
Output does
not change
CTM O/P Pin
Output pin set to
initial Level Low if
CTOC=0
Output Toggle with
CTMAF flag
Here CTIO [1:0] = 11
Toggle Output select
Output not affected by
CTMAF flag. Remains High
until reset by CTON bit
Note CTIO [1:0] = 10
Active High Output select
Output Inverts
when CTPOL is high
Output Pin
Reset to Initial value
Output controlled by
other pin-shared function
Compare Match Output Mode – CTCCLR=1
Note: 1. With CTCCLR=1, a Comparator A match will clear the counter
2. The CTM 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
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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
CTM 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 CTM 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, bits CTM1 and CTM0 in the CTMC1 register should be set to “10” respectively.
The PWM function within the CTM 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 CTM output pin, a square wave AC waveform can be generated with
varying equivalent DC RMS values.
As both the period and duty cycle of the PWM waveform can be controlled, the choice of generated
waveform is extremely flexible. In the PWM Output Mode, the 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 CTM output pin to a fixed high or low level. The CTPOL bit
is used to reverse the polarity of the PWM output waveform.
• 16-bit CTM, PWM Output Mode, Edge-aligned Mode, CTDPX=0
CCRP
1~255
0
Period
CCRP×256
65536
Duty
CCRA
If fSYS=8MHz, CTM clock source is fSYS/4, CCRP=2, CCRA=128,
The CTM PWM output frequency=(fSYS/4)/512=fSYS/2048≈4kHz, 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%.
• 16-bit CTM, PWM Output Mode, Edge-aligned Mode, CTDPX=1
CCRP
1~255
Period
0
CCRA
Duty
CCRP×256
65536
The PWM output period is determined by the CCRA register value together with the CTM clock
while the PWM duty cycle is defined by the CCRP register value.
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Counter Value
CTDPX = 0; CTM [1:0] = 10
Counter cleared by
CCRP
Counter Reset when
CTON returns high
CCRP
Pause
Resume
Counter Stop if
CTON bit low
CCRA
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 resumes
Output controlled by
operation
other pin-shared function
Output Inverts
when CTPOL = 1
PWM Period set by CCRP
PWM Duty Cycle
set by CCRA
PWM Output 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 even when CTIO[1:0]=00 or 01
4. The CTCCLR bit has no influence on PWM operation
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Counter Value
CTDPX = 1; CTM [1:0] = 10
Counter cleared by
CCRA
Counter Reset when
CTON returns high
CCRA
Pause
Resume
Counter Stop if
CTON bit low
CCRP
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
PWM resumes
Output controlled by
operation
other pin-shared function
Output Inverts
when CTPOL = 1
PWM Period set by CCRA
PWM Output 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 even when CTIO [1:0]=00 or 01
4. The CTCCLR bit has no influence on PWM operation
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Standard Type TM – STM
The Standard Type TM contains five operating modes, which are Compare Match Output, Timer/
Event Counter, Capture Input, Single Pulse Output and PWM Output modes. The Standard TM can
also be controlled with two external input pins and can drive one external output pin.
STM Core
STM Input Pin
STM Output Pin
16-bit STM
STCK, STP
STP
CCRP
fSYS/4
fSYS
fH/16
fH/64
fSUB
fSUB
STCK
000
001
010
011
100
101
110
111
8-bit Comparator P
Comparator P Match
STOC
b8~b15
16-bit Count-up Counter
STON
STPAU
STCK2~STCK0
Counter Clear 0
1
STCCLR
b0~b15
16-bit Comparator A
STMPF Interrupt
Comparator A Match
STIO1, STIO0
Output
Control
Polarity
Control
Pin
Control
STM1, STM0
STIO1, STIO0
STPOL
T0CP
STP
STMAF Interrupt
Edge
Detector
CCRA
16-bit Standard Type TM Block Diagram
Standard Type TM Operation
The size of Standard TM is 16-bit wide and its core is a 16-bit count-up counter which is driven by
a user selectable internal or external clock source. There are also two internal comparators with the
names, Comparator A and Comparator P. These comparators will compare the value in the counter
with CCRP and CCRA registers. The CCRP comparator is 8-bit wide whose value is compared
with the highest 8 bits in the counter while the CCRA is the sixteen bits and therefore compares all
counter bits.
The only way of changing the value of the 16-bit counter using the application program, is to
clear the counter by changing the STON bit from low to high. The counter will also be cleared
automatically by a counter overflow or a compare match with one of its associated comparators.
When these conditions occur, a STM interrupt signal will also usually be generated. The Standard
Type TM can operate in a number of different operational modes, can be driven by different clock
sources including an input pin and can also control the output pin. All operating setup conditions are
selected using relevant internal registers.
Standard Type TM Register Description
Overall operation of the Standard TM is controlled using a series of registers. A read only register
pair exists to store the internal counter 16-bit value, while a read/write register pair exists to store
the internal 16-bit CCRA value. The STMRP register is used to store the 8-bit CCRP value. The
remaining two registers are control registers which setup the different operating and control modes.
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Bit
Register
Name
7
6
5
4
STMC0
STPAU
STCK2
STCK1
STCK0
STON
—
—
—
STMC1
STM1
STM0
STIO1
STIO0
STOC
STPOL
STDPX
STCCLR
D0
3
2
1
0
STMDL
D7
D6
D5
D4
D3
D2
D1
STMDH
D15
D14
D13
D12
D11
D10
D9
D8
STMAL
D7
D6
D5
D4
D3
D2
D1
D0
STMAH
D15
D14
D13
D12
D11
D10
D9
D8
STMRP
STRP7
STRP6
STRP5
STRP4
STRP3
STRP2
STRP1
STRP0
1
0
16-bit Standard TM Register List
• STMC0 Register
Bit
7
6
5
4
3
2
Name
STPAU
STCK2
STCK1
STCK0
STON
—
—
—
R/W
R/W
R/W
R/W
R/W
R/W
—
—
—
POR
0
0
0
0
0
—
—
—
Bit 7 STPAU: STM counter pause control
0: Run
1: Pause
The counter can be paused by setting this bit high. Clearing the bit to zero restores
normal counter operation. When in a Pause condition the STM will remain powered up
and continue to consume power. The counter will retain its residual value when this bit
changes from low to high and resume counting from this value when the bit changes to
a low value again.
Bit 6~4 STCK2~STCK0: STM counter clock selection
000: fSYS/4
001: fSYS
010: fH/16
011: fH/64
100: fSUB
101: fSUB
110: STCK rising edge clock
111: STCK falling edge clock
These three bits are used to select the clock source for the STM. The external pin clock
source can be chosen to be active on the rising or falling edge. The clock source fSYS is
the system clock, while fH and fSUB are other internal clocks, the details of which can
be found in the oscillator section.
Bit 3 STON: STM counter on/off control
0: Off
1: On
This bit controls the overall on/off function of the STM. Setting the bit high enables
the counter to run while clearing the bit disables the STM. Clearing this bit to zero
will stop the counter from counting and turn off the STM which will reduce its power
consumption. When the bit changes state from low to high the internal counter value
will be reset to zero, however when the bit changes from high to low, the internal
counter will retain its residual value until the bit returns high again. If the STM is in
the Compare Match Output Mode or PWM output Mode or Single Pulse Output Mode,
then the STM output pin will be reset to its initial condition, as specified by the STOC
bit, when the STON bit changes from low to high.
Bit 2~0
Rev. 1.20
Unimplemented, read as “0”
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• STMC1 Register
Bit
7
6
5
4
3
2
1
0
Name
STM1
STM0
STIO1
STIO0
STOC
STPOL
STDPX
STCCLR
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~6 STM1~STM0: STM operating mode selection
00: Compare Match Output Mode
01: Capture Input Mode
10: PWM Output Mode or Single Pulse Output Mode
11: Timer/Counter Mode
These bits setup the required operating mode for the STM. To ensure reliable operation
the STM should be switched off before any changes are made to the STM1 and STM0
bits. In the Timer/Counter Mode, the STM output pin control must be disabled.
Bit 5~4 STIO1~STIO0: STM STP pin function selection
Compare Match Output Mode
00: No change
01: Output low
10: Output high
11: Toggle output
PWM Output Mode/Single Pulse Output Mode
00: PWM output inactive state
01: PWM output active state
10: PWM output
11: Single Pulse Output
Capture Input Mode
00: Input capture at rising edge of STP
01: Input capture at falling edge of STP
10: Input capture at rising/falling edge of STP
11: Input capture disabled
Timer/Counter Mode
Unused
These two bits are used to determine how the STM output pin changes state when a
certain condition is reached. The function that these bits select depends upon in which
mode the STM is running.
In the Compare Match Output Mode, the STIO1 and STIO0 bits determine how the
STM 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 STM output
pin should be setup using the STOC bit in the STMC1 register. Note that the output
level requested by the STIO1 and STIO0 bits must be different from the initial value
setup using the STOC bit otherwise no change will occur on the STM output pin when
a compare match occurs. After the STM output pin changes state, it can be reset to its
initial level by changing the level of the STON bit from low to high.
In the PWM Output Mode, the STIO1 and STIO0 bits determine how the STM
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 STIO1 and STIO0 bits only after the STM has been switched off.
Unpredictable PWM outputs will occur if the STIO1 and STIO0 bits are changed
when the STM is running.
Rev. 1.20
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Bit 3 STOC: STM STP output control
Compare Match Output Mode
0: Initial low
1: Initial high
PWM Output Mode/Single Pulse Output Mode
0: Active low
1: Active high
This is the output control bit for the STM output pin. Its operation depends upon
whether STM is being used in the Compare Match Output Mode or in the PWM
Output Mode/Single Pulse Output Mode. It has no effect if the STM is in the Timer/
Counter Mode. In the Compare Match Output Mode it determines the logic level of
the STM output pin before a compare match occurs. In the PWM Output Mode it
determines if the PWM signal is active high or active low. In the Single Pulse Output
Mode it determines the logic level of the STM output pin when the STON bit changes
from low to high.
Bit 2 STPOL: STM STP output polarity control
0: Non-invert
1: Invert
This bit controls the polarity of the STP output pin. When the bit is set high the STM
output pin will be inverted and not inverted when the bit is zero. It has no effect if the
STM is in the Timer/Counter Mode.
Bit 1 STDPX: STM PWM duty/period control
0: CCRP – period; CCRA – duty
1: CCRP – duty; CCRA – period
This bit determines which of the CCRA and CCRP registers are used for period and
duty control of the PWM waveform.
Bit 0 STCCLR: STM counter clear condition selection
0: Comparator P match
1: Comparator A match
This bit is used to select the method which clears the counter. Remember that the
Standard TM contains two comparators, Comparator A and Comparator P, either of
which can be selected to clear the internal counter. With the STCCLR bit set high,
the counter will be cleared when a compare match occurs from the Comparator A.
When the bit is low, the counter will be cleared when a compare match occurs from
the Comparator P or with a counter overflow. A counter overflow clearing method can
only be implemented if the CCRP bits are all cleared to zero. The STCCLR bit is not
used in the PWM Output Mode, Single Pulse Output Mode or Capture Input Mode.
• STMDL Register
Bit
7
6
5
4
3
2
1
0
Name
D7
D6
D5
D4
D3
D2
D1
D0
R/W
R
R
R
R
R
R
R
R
POR
0
0
0
0
0
0
0
0
Bit 7~0
D7~D0: STM Counter Low Byte Register bit 7 ~ bit 0
STM 16-bit Counter bit 7 ~ bit 0
• STMDH Register
Bit
7
6
5
4
3
2
1
0
Name
D15
D14
D13
D12
D11
D10
D9
D8
R/W
R
R
R
R
R
R
R
R
POR
0
0
0
0
0
0
0
0
Bit 7~0
Rev. 1.20
D15~D8: STM Counter High Byte Register bit 7 ~ bit 0
STM 16-bit Counter bit 15 ~ bit 8
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• STMAL Register
Bit
7
6
5
4
3
2
1
0
Name
D7
D6
D5
D4
D3
D2
D1
D0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~0
D7~D0: STM CCRA Low Byte Register bit 7 ~ bit 0
STM 16-bit CCRA bit 7 ~ bit 0
• STMAH Register
Bit
7
6
5
4
3
2
1
0
Name
D15
D14
D13
D12
D11
D10
D9
D8
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~0
D15~D8: STM CCRA High Byte Register bit 7 ~ bit 0
STM 16-bit CCRA bit 15 ~ bit 8
• STMRP Register
Bit
7
6
5
4
3
2
1
0
Name
STRP7
STRP6
STRP5
STRP4
STRP3
STRP2
STRP1
STRP0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~0
Rev. 1.20
STRP7~STRP0: STM CCRP 8-bit register, compared with the STM counter bit 15 ~ bit 8
Comparator P match period =
0: 65536 STM clocks
1~255: (1~255) × 256 STM clocks
These eight bits are used to setup the value on the internal CCRP 8-bit register, which
are then compared with the internal counter's highest eight bits. The result of this
comparison can be selected to clear the internal counter if the STCCLR bit is set to
zero. Setting the STCCLR bit to zero ensures that a compare match with the CCRP
values will reset the internal counter. As the CCRP bits are only compared with the
highest eight counter bits, the compare values exist in 256 clock cycle multiples.
Clearing all eight bits to zero is in effect allowing the counter to overflow at its
maximum value.
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A/D Flash MCU with EEPROM
Standard Type TM Operation Modes
The Standard Type TM can operate in one of five operating modes, Compare Match Output Mode,
PWM Output Mode, Single Pulse Output Mode, Capture Input Mode or Timer/Counter Mode. The
operating mode is selected using the STM1 and STM0 bits in the STMC1 register.
Compare Match Output Mode
To select this mode, bits STM1 and STM0 in the STMC1 register, should be set to “00” respectively.
In this mode once the counter is enabled and running it can be cleared by three methods. These are
a counter overflow, a compare match from Comparator A and a compare match from Comparator P.
When the STCCLR bit is low, there are two ways in which the counter can be cleared. One is when
a compare match from Comparator P, the other is when the CCRP bits are all zero which allows the
counter to overflow. Here both STMAF and STMPF interrupt request flags for Comparator A and
Comparator P respectively, will both be generated.
If the STCCLR bit in the STMC1 register is high then the counter will be cleared when a compare
match occurs from Comparator A. However, here only the STMAF interrupt request flag will be
generated even if the value of the CCRP bits is less than that of the CCRA registers. Therefore when
STCCLR is high no STMPF interrupt request flag will be generated. In the Compare Match Output
Mode, the CCRA can not be set to “0”.
If the CCRA bits are all zero, the counter will overflow when it reaches its maximum 16-bit, FFFF
Hex, value, however here the STMAF interrupt request flag will not be generated.
As the name of the mode suggests, after a comparison is made, the STM output pin, will change
state. The STM output pin condition however only changes state when a STMAF interrupt request
flag is generated after a compare match occurs from Comparator A. The STMPF interrupt request
flag, generated from a compare match occurs from Comparator P, will have no effect on the STM
output pin. The way in which the STM output pin changes state are determined by the condition of
the STIO1 and STIO0 bits in the STMC1 register. The STM output pin can be selected using the
STIO1 and STIO0 bits to go high, to go low or to toggle from its present condition when a compare
match occurs from Comparator A. The initial condition of the STM output pin, which is setup after
the STON bit changes from low to high, is setup using the STOC bit. Note that if the STIO1 and
STIO0 bits are zero then no pin change will take place.
Rev. 1.20
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A/D Flash MCU with EEPROM
STCCLR = 0; STM [1:0] = 00
Counter overflow
Counter Value
CCRP > 0
Counter cleared by CCRP value
CCRP=0
0xFFFF
CCRP > 0
Counter
Restart
Resume
CCRP
Pause
CCRA
Stop
Time
STON
STPAU
STPOL
CCRP Int. flag
STMPF
CCRA Int. flag
STMAF
STM O/P Pin
Output pin set
to initial Level
Low if STOC=0
Output not affected by
STMAF flag. Remains High
until reset by STON bit
Output Toggle
with STMAF flag
Here STIO [1:0] = 11
Toggle Output select
Note STIO [1:0] = 10
Active High Output select
Output Inverts
when STPOL is high
Output Pin
Reset to Initial value
Output controlled by
other pin-shared function
Compare Match Output Mode – STCCLR=0
Note: 1. With STCCLR=0, a Comparator P match will clear the counter
2. The STM output pin is controlled only by the STMAF flag
3. The output pin is reset to its initial state by a STON bit rising edge
Rev. 1.20
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A/D Flash MCU with EEPROM
Counter Value
STCCLR = 1; STM [1:0] = 00
CCRA = 0
Counter overflow
CCRA > 0 Counter cleared by CCRA value
0xFFFF
CCRA=0
Resume
CCRA
Pause
Stop
Counter Restart
CCRP
Time
STON
STPAU
STPOL
No STMAF flag
generated on
CCRA overflow
CCRA Int.
flag STMAF
CCRP Int.
flag STMPF
STMnPF not
generated
Output does
not change
STM O/P Pin
Output pin set
to initial Level
Low if STOC=0
Output Toggle with
STMAF flag
Here STIO [1:0] = 11
Toggle Output select
Output not affected by
STMAF flag. Remains High
until reset by STON bit
Note STIO [1:0] = 10
Active High Output select
Output Inverts
when STPOL is high
Output Pin
Reset to Initial value
Output controlled by
other pin-shared function
Compare Match Output Mode – STCCLR=1
Note: 1. With STCCLR=1, a Comparator A match will clear the counter
2. The STM output pin is controlled only by the STMAF flag
3. The output pin is reset to its initial state by a STON bit rising edge
4. The STMPF flag is not generated when STCCLR=1
Rev. 1.20
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A/D Flash MCU with EEPROM
Timer/Counter Mode
To select this mode, bits STM1 and STM0 in the STMC1 register should be set to “11” respectively.
The Timer/Counter Mode operates in an identical way to the Compare Match Output Mode
generating the same interrupt flags. The exception is that in the Timer/Counter Mode the STM
output pin is not used. Therefore the above description and Timing Diagrams for the Compare
Match Output Mode can be used to understand its function. As the STM output pin is not used in
this mode, the pin can be used as a normal I/O pin or other pin-shared functions.
PWM Output Mode
To select this mode, bits STM1 and STM0 in the STMC1 register should be set to “10” respectively
and also the STIO1 and STIO0 bits should be set to “10” respectively. The PWM function within
the STM is useful for applications which require functions such as motor control, heating control,
illumination control etc. By providing a signal of fixed frequency but of varying duty cycle on the
STM output pin, a square wave AC waveform can be generated with varying equivalent DC RMS
values.
As both the period and duty cycle of the PWM waveform can be controlled, the choice of generated
waveform is extremely flexible. In the PWM Output Mode, the STCCLR bit has no effect as the
PWM period. Both of the CCRA and CCRP registers are used to generate the PWM waveform, one
register is used to clear the internal counter and thus control the PWM waveform frequency, while
the other one is used to control the duty cycle. Which register is used to control either frequency
or duty cycle is determined using the STDPX bit in the STMC1 register. The PWM waveform
frequency and duty cycle can therefore be controlled by the values in the CCRA and CCRP registers.
An interrupt flag, one for each of the CCRA and CCRP, will be generated when a compare match
occurs from either Comparator A or Comparator P. The STOC bit in the STMC1 register is used to
select the required polarity of the PWM waveform while the two STIO1 and STIO0 bits are used to
enable the PWM output or to force the STM output pin to a fixed high or low level. The STPOL bit
is used to reverse the polarity of the PWM output waveform.
• 16-bit STM, PWM Output Mode, Edge-aligned Mode, STDPX=0
CCRP
1~255
0
Period
CCRP×256
65536
Duty
CCRA
If fSYS=8MHz, STM clock source is fSYS/4, CCRP=2 and CCRA=128,
The STM PWM output frequency=(fSYS/4)/(2×256)=fSYS/2048≈4kHz, duty=128/(2×256)=25%.
If the Duty value defined by the CCRA register is equal to or greater than the Period value, then the
PWM output duty is 100%.
• 16-bit STM, PWM Output Mode, Edge-aligned Mode, STDPX=1
CCRP
1~255
Period
Duty
0
CCRA
CCRP×256
65536
The PWM output period is determined by the CCRA register value together with the STM clock
while the PWM duty cycle is defined by the CCRP register value except when the CCRP value is
equal to 0.
Rev. 1.20
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A/D Flash MCU with EEPROM
Counter Value
STDPX = 0; STM [1:0] = 10
Counter cleared by
CCRP
Counter Reset when
STON returns high
CCRP
Pause
Resume
Counter Stop if
STON bit low
CCRA
Time
STON
STPAU
STPOL
CCRA Int.
flag STMAF
CCRP Int.
flag STMPF
STM O/P Pin
(STOC=1)
STM O/P Pin
(STOC=0)
PWM Duty Cycle
set by CCRA
PWM resumes
operation
Output controlled by
Output Inverts
other pin-shared function
when STPOL = 1
PWM Period set by CCRP
PWM Output Mode – STDPX=0
Note: 1. Here STDPX=0 – Counter cleared by CCRP
2. A counter clear sets the PWM Period
3. The internal PWM function continues even when STIO[1:0]=00 or 01
4. The STCCLR bit has no influence on PWM operation
Rev. 1.20
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A/D Flash MCU with EEPROM
Counter Value
STDPX = 1; STM [1:0] = 10
Counter cleared by
CCRA
Counter Reset when
STON returns high
CCRA
Pause
Resume
Counter Stop if
STON bit low
CCRP
Time
STON
STPAU
STPOL
CCRP Int.
flag STMPF
CCRA Int.
flag STMAF
STM O/P Pin
(STOC=1)
STM O/P Pin
(STOC=0)
PWM resumes
operation
Output controlled by
Output Inverts
other pin-shared function
when STPOL = 1
PWM Period set by CCRA
PWM Duty Cycle
set by CCRP
PWM Output Mode – STDPX=1
Note: 1. Here STDPX=1 – Counter cleared by CCRA
2. A counter clear sets the PWM Period
3. The internal PWM function continues even when STIO [1:0]=00 or 01
4. The STCCLR bit has no influence on PWM operation
Rev. 1.20
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A/D Flash MCU with EEPROM
Single Pulse Output Mode
To select this mode, bits STM1 and STM0 in the STMC1 register should be set to “10” respectively
and also the STIO1 and STIO0 bits should be set to “11” respectively. The Single Pulse Output
Mode, as the name suggests, will generate a single shot pulse on the STM output pin.
The trigger for the pulse output leading edge is a low to high transition of the STON bit, which
can be implemented using the application program. However in the Single Pulse Output Mode, the
STON bit can also be made to automatically change from low to high using the external STCK pin,
which will in turn initiate the Single Pulse output. When the STON bit transitions to a high level, the
counter will start running and the pulse leading edge will be generated. The STON bit should remain
high when the pulse is in its active state. The generated pulse trailing edge will be generated when
the STON bit is cleared to zero, which can be implemented using the application program or when a
compare match occurs from Comparator A.
However a compare match from Comparator A will also automatically clear the STON bit and
thus generate the Single Pulse output trailing edge. In this way the CCRA value can be used to
control the pulse width. A compare match from Comparator A will also generate a STM interrupt.
The counter can only be reset back to zero when the STON bit changes from low to high when the
counter restarts. In the Single Pulse Output Mode CCRP is not used. The STCCLR and STDPX bits
are not used in this Mode.
S/W Command
SET“STON”
or
STCK Pin
Transition
CCRA
Leading Edge
CCRA
Trailing Edge
STON bit
0→1
STON bit
1→0
S/W Command
CLR“STON”
or
CCRA Compare
Match
STP Output Pin
Pulse Width = CCRA Value
Single Pulse Generation
Rev. 1.20
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A/D Flash MCU with EEPROM
Counter Value
STM [1:0] = 10 ; STIO [1:0] = 11
Counter stopped by
CCRA
Counter Reset when
STON returns high
CCRA
Pause
Counter Stops by
software
Resume
CCRP
Time
STON
Software
Trigger
Auto. set by
STCK pin
Cleared by
CCRA match
STCK pin
Software
Trigger
Software
Trigger
Software
Software Trigger
Clear
STCK pin
Trigger
STPAU
STPOL
No CCRP Interrupts
generated
CCRP Int.
Flag STMPF
CCRA Int.
Flag STMAF
STM O/P Pin
(STOC=1)
STM O/P Pin
(STOC=0)
Output Inverts
when STPOL = 1
Pulse Width
set by CCRA
Single Pulse Output Mode
Note: 1. Counter stopped by CCRA
2. CCRP is not used
3. The pulse triggered by the STCK pin or by setting the STON bit high
4. A STCK pin active edge will automatically set the STON bit high
5. In the Single Pulse Output Mode, STIO[1:0] must be set to “11” and can not be changed
Rev. 1.20
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Capture Input Mode
To select this mode bits STM1 and STM0 in the STMC1 register should be set to “01” respectively.
This mode enables external signals to capture and store the present value of the internal counter
and can therefore be used for applications such as pulse width measurements. The external signal
is supplied on the STP pin, whose active edge can be a rising edge, a falling edge or both rising
and falling edges; the active edge transition type is selected using the STIO1 and STIO0 bits in
the STMC1 register. The counter is started when the STON bit changes from low to high which is
initiated using the application program.
When the required edge transition appears on the STP pin the present value in the counter will be
latched into the CCRA registers and a STM interrupt generated. Irrespective of what events occur on
the STP pin the counter will continue to free run until the STON bit changes from high to low. When
a CCRP compare match occurs the counter will reset back to zero; in this way the CCRP value
can be used to control the maximum counter value. When a CCRP compare match occurs from
Comparator P, a STM interrupt will also be generated. Counting the number of overflow interrupt
signals from the CCRP can be a useful method in measuring long pulse widths. The STIO1 and
STIO0 bits can select the active trigger edge on the STP pin to be a rising edge, falling edge or both
edge types. If the STIO1 and STIO0 bits are both set high, then no capture operation will take place
irrespective of what happens on the STP pin, however it must be noted that the counter will continue
to run. The STCCLR and STDPX bits are not used in this mode.
Rev. 1.20
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A/D Flash MCU with EEPROM
Counter Value
STM [1:0] = 01
Counter cleared by
CCRP
Counter
Stop
Counter
Reset
CCRP
Resume
YY
Pause
XX
Time
STON
STPAU
Active
edge
Active
edge
Active edge
STM capture
pin STP
CCRA Int.
Flag STMAF
CCRP Int.
Flag STMPF
CCRA Value
STIO [1:0]
Value
XX
00 – Rising edge
YY
01 – Falling edge
YY
XX
10 – Both edges
11 – Disable Capture
Capture Input Mode
Note: 1. STM [1:0]=01 and active edge set by the STIO[1:0] bits
2. A STM Capture input pin active edge transfers the counter value to CCRA
3. STCCLR bit not used
4. No output function – STOC and STPOL bits are not used
5. CCRP determines the counter value and the counter has a maximum count value when CCRP is equal to zero
Rev. 1.20
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A/D Flash MCU with EEPROM
Periodic Type TM – PTM
The Periodic Type TM contains five operating modes, which are Compare Match Output, Timer/
Event Counter, Capture Input, Single Pulse Output and PWM Output modes. The Periodic TM can
also be controlled with two external input pins and can drive one external output pin.
PTM Core
PTM Input Pin
PTM Output Pin
10-bit PTM
PTCK, PTP
PTP
CCRP
10-bit Comparator P
fSYS/4
fSYS
fSYS/16
fSYS/64
fSUB
fSUB
PTCK
000
001
010
011
100
101
110
111
Comparator P Match
PTMPF Interrupt
PTOC
b0~b9
10-bit Count-up Counter
PTON
PTPAU
PTCK2~PTCK0
Counter Clear
Polarity
Control
Pin
Control
PTM1, PTM0
PTIO1, PTIO0
PTPOL
T1CP
PTCCLR
b0~b9
10-bit Comparator A
Output
Control
0
1
Comparator A Match
PTIO1, PTIO0
CCRA
Edge
Detector
PTP
PTMAF Interrupt
PTCAPTS
0
1
10-bit Periodic Type TM Block Diagram
Periodic Type TM Operation
The size of Periodic TM is 10-bit wide and its core is a 10-bit count-up counter which is driven by
a user selectable internal or external clock source. There are also two internal comparators with the
names, Comparator A and Comparator P. These comparators will compare the value in the counter
with CCRP and CCRA registers. The CCRP and CCRA comparators are 10-bit wide whose value is
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 PTM 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 two output pins. All operating setup conditions
are selected using relevant internal registers.
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.
Rev. 1.20
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A/D Flash MCU with EEPROM
Bit
Register
Name
7
6
5
4
3
PTMC0
PTPAU
PTCK2
PTCK1
PTCK0
PTON
—
PTMC1
PTM1
PTM0
PTIO1
PTIO0
PTOC
PTPOL
2
1
0
—
—
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
PTRP7
PTRP6
PTRP5
PTRP4
PTRP3
PTRP2
PTRP1
PTRP0
PTMRPH
—
—
—
—
—
—
PTRP9
PTRP8
10-bit Periodic TM Register List
• PTMC0 Register
Bit
7
6
5
4
3
2
1
0
Name
PTPAU
PTCK2
PTCK1
PTCK0
PTON
—
—
—
R/W
R/W
R/W
R/W
R/W
R/W
—
—
—
POR
0
0
0
0
0
—
—
—
Bit 7 PTPAU: 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 PTM 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 PTCK2~PTCK0: PTM counter clock selection
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 PTM. 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 3 PTON: PTM counter on/off control
0: Off
1: On
This bit controls the overall on/off function of the PTM. Setting the bit high enables
the counter to run while clearing the bit disables the PTM. Clearing this bit to zero
will stop the counter from counting and turn off the PTM 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 PTM is in
the Compare Match Output Mode or PWM output Mode or Single Pulse Output Mode,
then the PTM output pin will be reset to its initial condition, as specified by the PTOC
bit, when the PTON bit changes from low to high.
Bit 2~0
Rev. 1.20
Unimplemented, read as “0”
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A/D Flash MCU with EEPROM
• 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 7~6 PTM1~PTM0: PTM operating mode selection
00: Compare Match Output Mode
01: Capture Input Mode
10: PWM Output Mode or Single Pulse Output Mode
11: Timer/Counter Mode
These bits setup the required operating mode for the PTM. To ensure reliable operation
the PTM should be switched off before any changes are made to the PTM1 and PTM0
bits. In the Timer/Counter Mode, the PTM output pin control must be disabled.
Bit 5~4 PTIO1~PTIO0: PTM external pin function selection
Compare Match Output Mode
00: No change
01: Output low
10: Output high
11: Toggle output
PWM Output Mode/Single Pulse Output Mode
00: PWM output inactive state
01: PWM output active state
10: PWM output
11: Single Pulse Output
Capture Input Mode
00: Input capture at rising edge of PTP or PTCK
01: Input capture at falling edge of PTP or PTCK
10: Input capture at rising/falling edge of PTP or PTCK
11: Input capture disabled
Timer/Counter Mode
Unused
These two bits are used to determine how the PTM output pin changes state when a
certain condition is reached. The function that these bits select depends upon in which
mode the PTM is running.
In the Compare Match Output Mode, the PTIO1 and PTIO0 bits determine how the
PTM output pin changes state when a compare match occurs from the Comparator A.
The PTM 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 PTM 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 PTM output pin when
a compare match occurs. After the PTM output pin changes state, it can be reset to its
initial level by changing the level of the PTON bit from low to high.
In the PWM Output Mode, the PTIO1 and PTIO0 bits determine how the PTM
output pin changes state when a certain compare match condition occurs. The PTM
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 PTM has been switched off.
Unpredictable PWM outputs will occur if the PTIO1 and PTIO0 bits are changed
when the PTM is running.
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A/D Flash MCU with EEPROM
Bit 3 PTOC: PTM PTP output control
Compare Match Output Mode
0: Initial low
1: Initial high
PWM Output Mode/Single Pulse Output Mode
0: Active low
1: Active high
This is the output control bit for the PTM output pin. Its operation depends upon
whether PTM is being used in the Compare Match Output Mode or in the PWM
Output Mode/Single Pulse Output Mode. It has no effect if the PTM is in the Timer/
Counter Mode. In the Compare Match Output Mode it determines the logic level of
the PTM output pin before a compare match occurs. In the PWM Output Mode it
determines if the PWM signal is active high or active low. In the Single Pulse Output
Mode it determines the logic level of the PTM output pin when the PTON bit changes
from low to high.
Bit 2 PTPOL: PTM 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 PTM
output pin will be inverted and not inverted when the bit is zero. It has no effect if the
PTM is in the Timer/Counter Mode.
Bit 1 PTCAPTS: PTM capture trigger source selection
0: From PTP pin
1: From PTCK pin
Bit 0 PTCCLR: PTM counter clear condition selection
0: Comparator P match
1: Comparator A match
This bit is used to select the method which clears the counter. Remember that the
Periodic TM contains two comparators, Comparator A and Comparator P, either of
which can be selected to clear the internal counter. With the 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 Output, Single Pulse Output or Capture Input Mode.
• PTMDL Register
Bit
7
6
5
4
3
2
1
0
Name
D7
D6
D5
D4
D3
D2
D1
D0
R/W
R
R
R
R
R
R
R
R
POR
0
0
0
0
0
0
0
0
2
1
0
Bit 7~0
D7~D0: PTM Counter Low Byte Register bit 7 ~ bit 0
PTM 10-bit Counter bit 7 ~ bit 0
• PTMDH Register
Bit
Rev. 1.20
7
6
5
4
3
Name
—
—
R/W
—
—
—
—
—
—
D9
D8
—
—
—
—
R
POR
—
—
R
—
—
—
—
0
0
Bit 7~2
Unimplemented, read as “0”
Bit 1~0
D9~D8: PTM Counter High Byte Register bit 1 ~ bit 0
PTM 10-bit Counter bit 9 ~ bit 8
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A/D Flash MCU with EEPROM
• PTMAL Register
Bit
7
6
5
4
3
2
1
0
Name
D7
D6
D5
D4
D3
D2
D1
D0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~0
D7~D0: PTM CCRA Low Byte Register bit 7 ~ bit 0
PTM 10-bit CCRA bit 7 ~ bit 0
• PTMAH Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
—
—
D9
D8
R/W
—
—
—
—
—
—
R/W
R/W
POR
—
—
—
—
—
—
0
0
Bit 7~2
Unimplemented, read as “0”
Bit 1~0
D9~D8: 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
PTRP7
PTRP6
PTRP5
PTRP4
PTRP3
PTRP2
PTRP1
PTRP0
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
PTRP7~PTRP0: PTM CCRP Low Byte Register bit 7 ~ bit 0
PTM 10-bit CCRP bit 7 ~ bit 0
• PTMRPH Register
Rev. 1.20
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
—
—
PTRP9
PTRP8
R/W
—
—
—
—
—
—
R/W
R/W
POR
—
—
—
—
—
—
0
0
Bit 7~2
Unimplemented, read as “0”
Bit 1~0
PTRP9~PTRP8: PTM CCRP High Byte Register bit 1 ~ bit 0
PTM 10-bit CCRP bit 9 ~ bit 8
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A/D Flash MCU with EEPROM
Periodic Type TM Operation Modes
The Periodic Type TM can operate in one of five operating modes, Compare Match Output Mode,
PWM Output Mode, Single Pulse Output Mode, Capture Input Mode or Timer/Counter Mode. The
operating mode is selected using the PTM1 and PTM0 bits in the PTMC1 register.
Compare Match Output Mode
To select this mode, bits PTM1 and PTM0 in the PTMC1 register, should be 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”.
If the CCRA bits are all zero, the counter will overflow when its reaches its maximum 10-bit, 3FF
Hex, value, however here the PTMAF interrupt request flag will not be generated.
As the name of the mode suggests, after a comparison is made, the PTM output pin will change
state. The PTM 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 PTM
output pin. The way in which the PTM output pin changes state are determined by the condition of
the PTIO1 and PTIO0 bits in the PTMC1 register. The PTM 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 PTM 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.
Rev. 1.20
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A/D Flash MCU with EEPROM
Counter overflow
Counter Value
CCRP > 0
Counter cleared by CCRP value
CCRP=0
0x3FF
CCRP > 0
PTCCLR = 0; PTM [1:0] = 00
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 PTM 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
Rev. 1.20
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A/D Flash MCU with EEPROM
Counter Value
PTCCLR = 1; PTM [1:0] = 00
CCRA = 0
Counter overflow
CCRA > 0 Counter cleared by CCRA value
0x3FF
CCRA=0
Resume
CCRA
Pause
Stop
Counter Restart
CCRP
Time
PTON
PTPAU
PTPOL
No PTMAF flag
generated on
CCRA overflow
CCRA Int.
Flag PTMAF
CCRP Int.
Flag PTMPF
PTMPF not
generated
Output does
not change
PTM O/P Pin
Output pin set
to initial Level
Low if PTOC=0
Output Toggle with
PTMAF flag
Here PTIO [1:0] = 11
Toggle Output select
Output not affected by
PTMAF flag. Remains High
until reset by PTON bit
Note PTIO [1:0] = 10
Active High Output select
Output Inverts
when PTPOL is high
Output Pin
Reset to Initial value
Output controlled by
other pin-shared function
Compare Match Output Mode – PTCCLR=1
Note: 1. With PTCCLR=1, a Comparator A match will clear the counter
2. The PTM 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
Rev. 1.20
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A/D Flash MCU with EEPROM
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 PTM
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 PTM 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, 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 PTM 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
PTM output pin, a square wave AC waveform can be generated with varying equivalent DC RMS
values.
As both the period and duty cycle of the PWM waveform can be controlled, the choice of generated
waveform is extremely flexible. In the PWM Output Mode, the PTCCLR bit has no effect as the
PWM period. Both of the CCRP and CCRA registers are used to generate the PWM waveform, one
register is used to clear the internal counter and thus control the PWM waveform frequency, while
the other one is used to control the duty cycle. The PWM waveform frequency and duty cycle can
therefore be controlled by the values in the CCRA and CCRP registers.
An interrupt flag, one for each of the CCRA and CCRP, will be generated when a compare match
occurs from either Comparator A or Comparator P. The PTOC bit in the PTMC1 register is used to
select the required polarity of the PWM waveform while the two PTIO1 and PTIO0 bits are used to
enable the PWM output or to force the PTM output pin to a fixed high or low level. The PTPOL bit
is used to reverse the polarity of the PWM output waveform.
• 10-bit PWM Output Mode, Edge-aligned Mode
CCRP
1~1023
Period
1~1023
Duty
0
1024
CCRA
If fSYS=8MHz, PTM clock source select fSYS/4, CCRP=512 and CCRA=128,
The PTM PWM output frequency=(fSYS/4)/512=fSYS/2048≈4kHz, duty=128/512=25%,
If the Duty value defined by the CCRA register is equal to or greater than the Period value, then the
PWM output duty is 100%.
Rev. 1.20
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A/D Flash MCU with EEPROM
Counter Value
PTM [1:0] = 10
Counter cleared by
CCRP
Counter Reset when
PTON returns high
CCRP
Pause
Resume
Counter Stop if
PTON bit low
CCRA
Time
PTON
PTPAU
PTPOL
CCRA Int.
Flag PTMAF
CCRP Int.
Flag PTMPF
PTM O/P Pin
(PTOC=1)
PTM O/P Pin
(PTOC=0)
PWM Duty Cycle
set by CCRA
PWM resumes
Output controlled by
operation
other pin-shared function
Output Inverts
When PTPOL = 1
PWM Period set by CCRP
PWM Output 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
Rev. 1.20
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A/D Flash MCU with EEPROM
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 PTM 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 Output 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 PTM 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 Output Mode CCRP is not used. The PTCCLR is not used in this Mode.
S/W Command
SET“PTON”
or
PTCK Pin
Transition
CCRA
Leading Edge
CCRA
Trailing Edge
PTON bit
1
0
PTON bit
0
1
S/W Command
CLR“PTON”
or
CCRA Compare
Match
PTP Output Pin
Pulse Width = CCRA Value
Single Pulse Generation
Rev. 1.20
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A/D Flash MCU with EEPROM
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
Clear
Software
Trigger
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)
Pulse Width
set by CCRA
Output Inverts
when PTPOL = 1
Single Pulse Output 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 Output Mode, PTIO[1:0] must be set to “11” and can not be changed
Rev. 1.20
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A/D Flash MCU with EEPROM
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 PTP or PTCK pin, selected by the PTCAPTS bit in the PTMC1 register. The input
pin active edge can be either a rising edge, a falling edge or both rising and falling edges; the active
edge transition type is selected using the PTIO1 and PTIO0 bits in the PTMC1 register. The counter
is started when the PTON bit changes from low to high which is initiated using the application
program.
When the required edge transition appears on the PTP or PTCK pin the present value in the counter
will be latched into the CCRA registers and a PTM interrupt generated. Irrespective of what events
occur on the PTP 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 PTM 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 PTP 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 PTP or PTCK pin, however it must be noted that
the counter will continue to run.
As the PTP or PTCK pin is pin shared with other functions, care must be taken if the PTM is in the
Capture Input Mode. This is because if the pin is setup as an output, then any transitions on this pin
may cause an input capture operation to be executed. The PTCCLR, PTOC and PTPOL bits are not
used in this mode.
Rev. 1.20
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A/D Flash MCU with EEPROM
Counter Value
PTM [1:0] = 01
Counter cleared by
CCRP
Counter
Stop
Counter
Reset
CCRP
Resume
YY
Pause
XX
Time
PTON
PTPAU
Active
edge
Active
edge
Active
edge
PTM capture pin
PTP or PTCK
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 PTM 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.
Rev. 1.20
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A/D Flash MCU with EEPROM
Analog to Digital Converter – ADC
The need to interface to real world analog signals is a common requirement for many electronic
systems. However, to properly process these signals by a microcontroller, they must first be
converted into digital signals by A/D converters. By integrating the A/D conversion electronic
circuitry into the microcontroller, the need for external components is reduced significantly with the
corresponding follow-on benefits of lower costs and reduced component space requirements.
A/D Converter Overview
The device contains a multi-channel analog to digital converter which can directly interface to external
analog signals, such as that from sensors or other control signals and convert these signals directly into
a 12-bit digital value. It also can convert the internal signals, such as the internal reference voltage,
into a 12-bit digital value. The external or internal analog signal to be converted is determined by
the SAINS and SACS bit fields. Note that when the internal analog signal is to be converted using
the SAINS bit field, the external channel analog input will be automatically be switched off. More
detailed information about the A/D converter input signal is described in the “A/D Converter Control
Registers” and “A/D Converter Input Signals” sections respectively.
External Input Channels
Internal Analog Signals
A/D Signal Select
12: AN0~AN11
6: VDD, VDD/2, VDD/4, VR, VR/2, VR/4
SAINS2~SAINS0,
SACS3~SACS0
The accompanying block diagram shows the overall internal structure of the A/D converter, together
with its associated registers.
VDD
fSYS
ACE11~ACE0
SACS3~SACS0
AN0
SACKS2~
SACKS0
÷ 2N
(N=0~7)
ADCEN
VSS
A/D Clock
AN1
ADRFS
SADOL
A/D Converter
A/D Data
Registers
SADOH
AN11
A/D Reference Voltage
START
ADBZ
ADCEN
SAINS2~SAINS0
VREF
SAVRS3~SAVRS0
VDD
VDD/2
VDD/4
VR
VR/2
VBG
VRI PGA
VREFI
(Gain=1~4)
VREFIPS
ADPGAEN
VREFPS
VDD
VR
VR/4
A/D Converter Structure
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A/D Converter Register Description
Overall operation of the A/D converter is controlled using seven registers. A read only register pair
exists to store the A/D converter data 12-bit value. One register pair, ACERL and ACERH, is used to
configure the external analog input pin function. The remaining three registers are control registers
which setup the operating and control function of the A/D converter.
Bit
Register
Name
7
6
5
4
3
2
1
0
SADOL(ADRFS=0)
D3
D2
D1
D0
—
—
—
—
SADOL(ADRFS=1)
D7
D6
D5
D4
D3
D2
D1
D0
SADOH(ADRFS=0)
D11
D10
D9
D8
D7
D6
D5
D4
SADOH(ADRFS=1)
—
—
—
—
D11
D10
D9
D8
SACS2
SACS1
SACS0
SADC0
START
ADBZ
ADCEN
ADRFS
SACS3
SADC1
SAINS2
SAINS1
SAINS0
—
—
SADC2
SACKS2 SACKS1 SACKS0
ADPGAEN VBGEN VREFIPS VREFPS SAVRS3 SAVRS2 SAVRS1 SAVRS0
ACERL
ACE7
ACE6
ACE5
ACE4
ACE3
ACE2
ACE1
ACE0
ACERH
—
—
—
—
ACE11
ACE10
ACE9
ACE8
A/D Converter Register List
A/D Converter Data Registers – SADOL, SADOH
As the device contains an internal 12-bit A/D converter, it requires two data registers to store the
converted value. These are a high byte register, known as SADOH, and a low byte register, known
as SADOL. After the conversion process takes place, these registers can be directly read by the
microcontroller to obtain the digitised conversion value. As only 12 bits of the 16-bit register space
is utilised, the format in which the data is stored is controlled by the ADRFS bit in the SADC0
register as shown in the accompanying table. D0~D11 are the A/D conversion result data bits.
Any unused bits will be read as zero. Note that the A/D converter data register contents will keep
unchanged if the A/D converter is disabled.
ADRFS
0
1
SADOH
7
6
5
D11 D10 D9
0
0
0
4
D8
0
SADOL
3
2
1
0
7
6
5
4
3
2
1
0
D7
D6
D5
D4
D3
D2
D1
D0
0
0
0
0
D11 D10 D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
A/D Converter Data Registers
A/D Converter Control Registers – SADC0, SADC1, SADC2, ACERL, ACERH
To control the function and operation of the A/D converter, several control registers known as
SADC0, SADC1, SADC2, ACERL and ACERH are provided. These 8-bit registers define functions
such as the selection of which analog channel is connected to the internal A/D converter, the digitised
data format, the A/D converter clock source as well as controlling the start function and monitoring
the A/D converter busy status. As the device contains only one actual analog to digital converter
hardware circuit, each of the external and internal analog signals must be routed to the converter. The
SAINS bit field in the SADC1 register and SACS bit field in the SADC0 register are used to which
analog signal derived from the external or internal signals will be connected to the A/D converter.
The A/D converter also contains programmable gain amplifier, PGA, to generate the A/D converter
internal reference voltage. The overall operation of the PGA is controlled using the SADC2 register.
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The analog input pin function selection bits in the ACERL and ACERH registers determine which
pins on I/O ports are used as analog inputs for the A/D converter input and which pins are not to be
used as the A/D converter input. When the pin is selected to be an A/D converter input, its original
function whether it is an I/O or other pin-shared function will be removed. In addition, any internal
pull-high resistor connected to the pin will be automatically removed if the pin is selected to be an
A/D converter input.
• SADC0 Register
Bit
7
6
5
4
3
2
1
0
Name
START
ADBZ
ADCEN
ADRFS
SACS3
SACS2
SACS1
SACS0
R/W
R/W
R
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7 START: Start the A/D conversion
0 → 1 → 0: Start A/D conversion
This bit is used to initiate an A/D conversion process. The bit is normally low but if set
high and then cleared low again, the A/D converter will initiate a conversion process.
Bit 6 ADBZ: A/D Converter busy flag
0: No A/D conversion is in progress
1: A/D conversion is in progress
This read only flag is used to indicate whether the A/D conversion is in progress or
not. When the START bit is set from low to high and then to low again, the ADBZ flag
will be set high to indicate that the A/D conversion is initiated. The ADBZ flag will be
cleared to zero after the A/D conversion is complete.
Bit 5 ADCEN: A/D Converter function enable control
0: Disable
1: Enable
This bit controls the A/D converter internal function. This bit should be set high to
enable the A/D converter. If the bit is set low, then the A/D converter will be switched
off reducing the device power consumption. When the A/D converter function is
disabled, the contents of the A/D converter data register pair, SADOH and SADOL,
will keep unchanged.
Bit 4 ADRFS: A/D Converter data format control
0: ADC output data format → SADOH=D[11:4]; SADOL=D[3:0]
1: ADC output data format → SADOH=D[11:8]; SADOL=D[7:0]
This bit controls the format of the 12-bit converted A/D converter value in the two
A/D converter data registers. Details are provided in the A/D converter data register
section.
Bit 3~0 SACS3~SACS0: A/D converter external analog input channel selection
0000: AN0
0001: AN1
0010: AN2
0011: AN3
0100: AN4
0101: AN5
0110: AN6
0111: AN7
1000: AN8
1001: AN9
1010: AN10
1011: AN11
1100~1111: Undefined, input floating
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• SADC1 Register
Bit
7
6
5
4
3
2
1
0
Name
SAINS2
SAINS1
SAINS0
—
—
SACKS2
SACKS1
SACKS0
R/W
R/W
R/W
R/W
—
—
R/W
R/W
R/W
POR
0
0
0
—
—
0
0
0
Bit 7~5 SAINS2~SAINS0: A/D converter input signal selection
000, 100: External signal – External analog channel input, ANn
001: Internal signal – Internal A/D converter power supply voltage VDD
010: Internal signal – Internal A/D converter power supply voltage VDD/2
011: Internal signal – Internal A/D converter power supply voltage VDD/4
101: Internal signal – Internal reference voltage VR
110: Internal signal – Internal reference voltage VR/2
111: Internal signal – Internal reference voltage VR/4
When the internal analog signal is selected to be converted, the external channel input
signal will automatically be switched off regardless of the SACS bit field value. The
internal reference voltage can be derived from various sources selected using the
SAVRS3~SAVRS0 bits in the SADC2 register.
Bit 4~3
Unimplemented, read as “0”
Bit 2~0 SACKS2~SACKS0: A/D conversion clock source selection
000: fSYS
001: fSYS/2
010: fSYS/4
011: fSYS/8
100: fSYS/16
101: fSYS/32
110: fSYS/64
111: fSYS/128
• SADC2 Register
Bit
7
6
Name
ADPGAEN
VBGEN
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
Bit 7
5
4
VREFIPS VREFPS
3
2
1
0
SAVRS3
SAVRS2
SAVRS1
SAVRS0
R/W
R/W
R/W
R/W
0
0
0
0
ADPGAEN: A/D converter PGA enable/disable control
0: Disable
1: Enable
This bit controls the internal PGA function to provide various reference voltage for
the A/D converter. When the bit is set high, the internal reference voltage, VR, can be
used as the internal converted signal or reference voltage by the A/D converter. If the
internal reference voltage is not used by the A/D converter, then the PGA function
should be properly configured to conserve power.
Bit 6 VBGEN: Internal Bandgap reference voltage enable control
0: Disable
1: Enable
This bit controls the internal Bandgap circuit on/off function to the A/D converter.
When the bit is set high, the Bandgap reference voltage can be used by the A/D
converter. If the Bandgap reference voltage is not used by the A/D converter and
the LVD or LVR function is disabled, then the bandgap reference circuit will be
automatically switched off to conserve power. When the Bandgap reference voltage
is switched on for use by the A/D converter, a time, tBGS, should be allowed for the
Bandgap circuit to stabilise before implementing an A/D conversion.
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Bit 5 VREFIPS: VREFI pin selection
0: Disable – VREFI pin is not selected
1: Enable – VREFI pin is selected
Bit 4 VREFPS: VREF pin selection
0: Disable – VREF pin is not selected
1: Enable – VREF pin is selected
Bit 3~0 SAVRS3~SAVRS0: A/D converter reference voltage selection
0000: VDD
0001: VREFI
0010: VREFI×2
0011: VREFI×3
0100: VREFI×4
1001: Reserved, can not be used
1010: VBG×2
1011: VBG×3
1100: VBG×4
1101~1111: VDD
When the A/D converter reference voltage source is selected to derive from the A/D
converter power supply VDD or the internal VBG voltage, the reference voltage which
comes from the external VREFI pin will be automatically switched off.
• ACERL Register
Bit
7
6
5
4
3
2
1
0
Name
ACE7
ACE6
ACE5
ACE4
ACE3
ACE2
ACE1
ACE0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7 ACE7: Defines PB3 is A/D input or not
0: Not A/D input
1: A/D input, AN7
Bit 6 ACE6: Defines PA7 is A/D input or not
0: Not A/D input
1: A/D input, AN6
Bit 5 ACE5: Defines PA6 is A/D input or not
0: Not A/D input
1: A/D input, AN5
Bit 4 ACE4: Defines PA5 is A/D input or not
0: Not A/D input
1: A/D input, AN4
Bit 3 ACE3: Defines PA4 is A/D input or not
0: Not A/D input
1: A/D input, AN3
Bit 2 ACE2: Defines PB2 is A/D input or not
0: Not A/D input
1: A/D input, AN2
Bit 1 ACE1: Defines PB1 is A/D input or not
0: Not A/D input
1: A/D input, AN1
Bit 0 ACE0: Defines PB0 is A/D input or not
0: Not A/D input
1: A/D input, AN0
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• ACERH Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
ACE11
ACE10
ACE9
ACE8
R/W
—
—
—
—
R/W
R/W
R/W
R/W
POR
—
—
—
—
0
0
0
0
Bit 7~4
Unimplemented, read as “0”
Bit 3 ACE11: Defines PA3 is A/D input or not
0: Not A/D input
1: A/D input, AN11
Bit 2 ACE10: Defines PB6 is A/D input or not
0: Not A/D input
1: A/D input, AN10
Bit 1 ACE9: Defines PB5 is A/D input or not
0: Not A/D input
1: A/D input, AN9
Bit 0 ACE8: Defines PB4 is A/D input or not
0: Not A/D input
1: A/D input, AN8
A/D Converter Reference Voltage
The actual reference voltage supply to the A/D converter can be supplied from the positive power
voltage, VDD, an external reference source supplied on pin VREFI or an internal reference source
derived from the Bandgap circuit. Then the selected reference voltage source can be amplified
through a programmable gain amplifier except the voltage sourced from VDD. The desired selection
is made using the SAVRS3~SAVRS0 bits in the SADC2 register and relevant pin function selection
bits. Note that the selected reference voltage can be output on the VREF pin which is pin-shared with
other functions by setting the VREFPS bit in the SADC2 register. As the VREFI and VREF pins
both are pin-shared with other functions, when the VREFI or VREF pin is selected as the reference
voltage input or output pin, the VREFI or VREF pin function selection bit should first be properly
configured to disable other pin-shared functions. However, if the A/D converter power supply or the
internal Bandgap reference signal is selected as the reference source, the reference voltage which
originates from the external VREFI pin will automatically be switched off by hardware. The internal
Bandgap reference circuit should first be enabled before the VBG is selected to be used. A specific
start-up time is necessary for the Bandgap circuit to become stable and accurate.
Note that the analog input signal values must not be allowed to exceed the value of the selected A/D
converter reference voltage.
SAVRS[3:0]
0000,
1101~1111
Reference Source
VDD
Internal A/D converter power supply voltage VDD
0001
0010
0011
External A/D converter reference voltage VREFI
VREFI pin
0100
1100
External A/D converter reference voltage VREFI×2
External A/D converter reference voltage VREFI×3
External A/D converter reference voltage VREFI×4
1010
1011
Description
Internal Bandgap voltage VBG×2
Bandgap circuit
Internal Bandgap voltage VBG×3
Internal Bandgap voltage VBG×4
A/D Converter Reference Voltage Selection
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A/D Converter Input Signals
All of the external A/D Converter analog input pins are pin-shared with the I/O pins as well as
other functions. The corresponding pin-shared function selection bits in the ACERL and ACERH
registers, determine whether the external input pins are setup as A/D converter analog channel
inputs or whether they have other functions. If the corresponding pin is setup to be an A/D converter
analog channel input, the original pin functions will be disabled. In this way, pins can be changed
under program control to change their function between A/D inputs and other functions. All pullhigh resistors, which are setup through register programming, will be automatically disconnected if
the pins are setup as A/D inputs. Note that it is not necessary to first setup the A/D pin as an input in
the port control register to enable the A/D converter input as when the relevant A/D converter input
function selection bits enable an A/D converter input, the status of the port control register will be
overridden.
The SAINS2~SAINS0 bits in the SADC1 register are used to determine that the analog signal to
be converted comes from the external channel input or internal analog signal. The SACS3~SACS0
bits in the SADC0 register are used to determine which external channel input is selected to be
converted. If the SAINS2~SAINS0 bits are set to “000” or “100”, the external channel input will be
selected to be converted and the SACS bit field can determine which external channel is selected to
be converted. When the SAINS field is set to the value of “x01”, “x10” or “x11”, one of the internal
analog signals will be selected to be converted. The internal analog signals can be derived from the
A/D converter supply power, VDD, or internal reference voltage, VR, with a specific ratio of 1, 1/2 or
1/4. If the internal analog signal is selected to be converted, the external channel signal input will
automatically be switched off regardless of the SACS field value.
SAINS[2:0]
000, 100
SACS[3:0]
Input Signals
0000~1011
AN0~AN11
Description
External channel analog input ANn
11xx
─
001
xxxx
VDD
Floating, no external channel is selected
010
xxxx
VDD/2
Internal A/D converter power supply voltage/2
011
xxxx
VDD/4
Internal A/D converter power supply voltage/4
101
xxxx
VR
110
xxxx
VR/2
Internal reference voltage/2
111
xxxx
VR/4
Internal reference voltage/4
Internal A/D converter power supply voltage
Internal reference voltage
A/D Converter Input Signal Selection
“x”: Don’t care
A/D Converter Operation
The START bit in the SADC0 register is used to start the A/D conversion. When the microcontroller
sets this bit from low to high and then low again, an analog to digital conversion cycle will be initiated.
The ADBZ bit in the SADC0 register is used to indicate whether the analog to digital conversion
process is in process or not. This bit will be automatically set to “1” by the microcontroller after an
A/D conversion is successfully initiated. When the A/D conversion is complete, the ADBZ will be
cleared to “0”. In addition, the corresponding A/D converter interrupt request flag will be set in the
interrupt control register, and if the interrupts are enabled, an appropriate internal interrupt signal will
be generated. This A/D converter internal interrupt signal will direct the program flow to the associated
A/D converter internal interrupt address for processing. If the A/D converter internal interrupt is
disabled, the microcontroller can be used to poll the ADBZ bit in the SADC0 register to check whether
it has been cleared as an alternative method of detecting the end of an A/D conversion cycle.
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The clock source for the A/D converter, which originates from the system clock f SYS, can be
chosen to be either fSYS or a subdivided version of fSYS. The division ratio value is determined by
the SACKS2~SACKS0 bits in the SADC1 register. Although the A/D conversion clock source is
determined by the system clock fSYS, and by bits SACKS2~SACKS0, there are some limitations
on the A/D conversion clock source speed that can be selected. As the recommended value of
permissible A/D conversion clock period, tADCK, is from 0.5μs to 10μs, care must be taken for
system clock frequencies. For example, if the system clock operates at a frequency of 8MHz,
the SACKS2~SACKS0 bits should not be set to “000”, “001” or “111”. Doing so will give A/D
conversion clock periods that are less than the minimum A/D conversion clock period or greater than
the maximum A/D conversion clock period which may result in inaccurate A/D conversion values.
Refer to the following table for examples, where values marked with an asterisk * special care must
be taken.
A/D Conversion Clock Period (tADCK)
fSYS
SACKS[2:0] SACKS[2:0] SACKS[2:0] SACKS[2:0] SACKS[2:0] SACKS[2:0] SACKS[2:0] SACKS[2:0]
=000
=001
=010
=011
=100
=101
=110
=111
(fSYS)
(fSYS/2)
(fSYS/4)
(fSYS/8)
(fSYS/16)
(fSYS/32)
(fSYS/64)
(fSYS/128)
1MHz
1μs
2μs
4μs
8μs
16μs*
32μs*
64μs*
128μs*
2MHz
500ns
1μs
2μs
4μs
8μs
16μs*
32μs*
64μs*
4MHz
250ns*
500ns
1μs
2μs
4μs
8μs
16μs*
32μs*
8MHz
125ns*
250ns*
500ns
1μs
2μs
4μs
8μs
16μs*
12MHz
83ns*
167ns*
333ns*
667ns
1.33μs
2.67μs
5.33μs
10.67μs*
16MHz
62.5ns*
125ns*
250ns*
500ns
1μs
2μs
4μs
8μs
A/D Conversion Clock Period Examples
Controlling the power on/off function of the A/D conversion circuitry is implemented using the
ADCEN bit in the SADC0 register. This bit must be set high to power on the A/D converter. When
the ADCEN bit is set high to power on the A/D conversion internal circuitry, a certain delay as
indicated in the timing diagram must be allowed before an A/D conversion is initiated. Even if no
pins are selected for use as A/D converter inputs by configuring the corresponding pin control bits,
if the ADCEN bit is high then some power will still be consumed. In power conscious applications
it is therefore recommended that the ADCEN is set low to reduce power consumption when the A/D
converter function is not being used.
A/D Conversion Rate and Timing Diagram
A complete A/D conversion contains two parts, data sampling and data conversion. The data
sampling which is defined as tADS takes 4 A/D conversion clock cycles and the data conversion takes
12 A/D converter clock cycles. Therefore a total of 16 A/D conversion clock cycles for an A/D
conversion which is defined as tADC are necessary.
Maximum single A/D conversion rate = A/D conversion clock period / 16
The accompanying diagram shows graphically the various stages involved in an analog to digital
conversion process and its associated timing. After an A/D conversion process has been initiated
by the application program, the microcontroller internal hardware will begin to carry out the
conversion, during which time the program can continue with other functions. The time taken for the
A/D conversion is 16tADCK clock cycles where tADCK is equal to the A/D conversion clock period.
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tON2ST
ADCEN
off
on
off
A/D sampling time
tADS
A/D sampling time
tADS
Start of A/D conversion
Start of A/D conversion
End of A/D
conversion
End of A/D
conversion
on
START
ADBZ
SACS[3:0]
0011B
(SAINS[2:0]=000B)
A/D channel switch
0010B
tADC
A/D conversion time
Start of A/D conversion
0000B
tADC
A/D conversion time
0001B
tADC
A/D conversion time
A/D Conversion Timing – External Channel Input
Summary of A/D Conversion Steps
The following summarises the individual steps that should be executed in order to implement an A/D
conversion process.
• Step 1
Select the required A/D conversion clock by properly programming the SACKS2~SACKS0 bits
in the SADC1 register.
• Step 2
Enable the A/D converter by setting the ADCEN bit in the SADC0 register to “1”.
• Step 3
Select which signal is to be connected to the internal A/D converter by correctly configuring the
SAINS and SACS bit fields.
Select the external channel input to be converted, go to Step 4.
Select the internal analog signal to be converted, go to Step 5.
• Step 4
If the A/D input signal comes from the external channel input selected by configuring the SAINS
bit field, the corresponding pin should first be configured as an A/D input function by configuring
the relevant pin function control bits. The desired external channel input should be selected by
configuring the SACS field. After this step, go to Step 6.
• Step 5
If the A/D input signal is selected to come from the internal analog signal, the SAINS field
should be properly configured and then the external channel analog input will automatically be
disconnected regardless of the SACS bit field value. After this step, go to Step 6.
• Step 6
Select the reference voltage source by configuring the SAVRS3~SAVRS0 bits in the SADC2
register. Enable the PGA if the PGA output voltage is selected as the A/D converter reference
voltage. If the PGA input signal comes from the external VREFI pin, the corresponding pin
function selection bit should first be properly configured. If the A/D converter power supply
voltage, internal Bandgap circuit voltage or its multiplication is selected, the reference voltage
sourced from the external input pin VREFI will automatically be switched off.
• Step 7
Select A/D converter output data format by configuring the ADRFS bit in the SADC0 register.
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• Step 8
If A/D converter interrupt is used, the interrupt control registers must be correctly configured to
ensure the A/D converter interrupt function is active. The master interrupt control bit, EMI, and
the A/D converter interrupt bits, ADE, must both set high in advance.
• Step 9
The A/D conversion procedure can now be initialised by setting the START bit from low to high
and then low again.
• Step 10
If A/D conversion is in progress, the ADBZ flag will be set high. After the A/D conversion
process is completed, the ADBZ flag will go low and then output data can be read from the
SADOH and SADOL registers. If the ADC interrupt is enabled and the stack is not full, data can
be acquired by interrupt service program.
Note: When checking for the end of the conversion process, if the method of polling the ADBZ bit
in the SADC0 register is used, the interrupt enable step above can be omitted.
Programming Considerations
During microcontroller operations where the A/D converter is not being used, the A/D conversion
internal circuitry can be switched off to reduce power consumption by clearing the ADCEN bit
in the SADC0 register. When this happens, the internal A/D conversion circuits will not consume
power irrespective of what analog voltage is applied to their input lines. If the A/D converter input
lines are used as normal I/Os, then care must be taken as if the input voltage is not at a valid logic
level, then this may lead to some increase in power consumption.
A/D Conversion Function
As the device contains a 12-bit A/D converter, its full-scale converted digitised value is equal to
FFFH. Since the full-scale analog input value is equal to the actual A/D converter reference voltage,
VREF, this gives a single bit analog input value of VREF divided by 4096.
1 LSB = VREF ÷ 4096
The A/D Converter input voltage value can be calculated using the following equation:
A/D converter input voltage = A/D converter output digital value × VREF ÷ 4096
The diagram shows the ideal transfer function between the analog input value and the digitised
output value for the A/D converter. Except for the digitised zero value, the subsequent digitised
values will change at a point 0.5 LSB below where they would change without the offset, and the
last full scale digitised value will change at a point 1.5 LSB below the VREF level. Note that here the
VREF voltage is the actual A/D converter reference voltage determined by the SAVRS field.
Note that here the VREF voltage is the actual A/D converter reference voltage determined by the
SAVRS bit field.
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1.5 LSB
FFFH
FFEH
FFDH
A/D Conversion
Result
03H
0.5 LSB
02H
01H
0
1
2
3
VREF
4096
4093 4094 4095 4096
Analog Input Voltage
Ideal A/D Conversion Function
A/D Converter Programming Examples
The following two programming examples illustrate how to setup and implement an A/D
conversion. In the first example, the method of polling the ADBZ bit in the SADC0 register is used
to detect when the conversion cycle is complete, whereas in the second example, the A/D converter
interrupt is used to determine when the conversion is complete.
Example: using an ADBZ polling method to detect the end of conversion
clr
ADE ;
mov
a,03H ;
;
mov SADC1,a
mov a,00H ;
mov SADC2,a
mov a,01h ;
mov ACERL,a
mov a,20h ;
mov SADC0,a
:
start_conversion:
clr START ;
set START ;
clr START ;
polling_EOC:
sz ADBZ ;
jmp polling_EOC ;
mov a,SADOL ;
mov SADOL_buffer,a ;
mov a,SADOH ;
mov SADOH_buffer,a ;
:
jmp start_conversion ;
Rev. 1.20
disable ADC interrupt
select fSYS/8 as A/D clock and A/D input signal comes from
external channel
select VDD as A/D reference voltage source
setup ACERL to configure pin AN0
enable A/D converter and select AN0 external channel input
high pulse on start bit to initiate conversion
reset A/D converter
start A/D conversion
poll the SADC0 register ADBZ bit to detect end of A/D conversion
continue polling
read low byte conversion result value
save result to user defined register
read high byte conversion result value
save result to user defined register
start next A/D conversion
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Example: using the interrupt method to detect the end of conversion
clr
ADE ;
mov
a,03H ;
mov SADC1,a
mov a,00H ;
mov SADC2,a
mov a,01h ;
mov ACERL,a
mov a,20h ;
mov SADC0,a
:
Start_conversion:
clr START ;
set START ;
clr START ;
clr ADF ;
set
ADE ;
set EMI ;
:
:
;
ADC_ISR:
mov acc_stack,a ;
mov a,STATUS
mov status_stack,a ;
:
:
mov a,SADOL ;
mov SADOL_buffer,a ;
mov a,SADOH ;
mov SADOH_buffer,a ;
:
:
EXIT_INT_ISR:
mov a,status_stack
mov STATUS,a ;
mov a,acc_stack ;
reti
Rev. 1.20
disable ADC interrupt
select fSYS/8 as A/D clock and A/D input signal comes from external channel
select VDD as A/D reference voltage source
setup ACERL to configure pin AN0
enable A/D converter and select AN0 external channel input
high pulse on START bit to initiate conversion
reset A/D converter
start A/D conversion
clear ADC interrupt request flag
enable ADC interrupt
enable global interrupt
ADC interrupt service routine
save ACC to user defined memory
save STATUS to user defined memory
read
save
read
save
low byte conversion result value
result to user defined register
high byte conversion result value
result to user defined register
restore STATUS from user defined memory
restore ACC from user defined memory
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Comparator
An analog comparator is contained within the device. The comparator function offers flexibility
via their register controlled features such as power-down, polarity select, hysteresis etc. In sharing
their pins with normal I/O pins the comparators do not waste precious I/O pins if there functions are
otherwise unused.
CPOL
C+
+
C-
-
COUT
CX
CINT COS
CSEL
Comparator
Comparator Operation
The device contains a comparator function which is used to compare two analog voltages and
provide an output based on their input difference. Full control over the internal comparator is
provided via the control register, CPC. The comparator output is recorded via a bit in the control
register, but can also be transferred output onto a shared I/O pin. Additional comparator functions
include polarity, hysteresis function and power down control.
Any pull-high resistors connected to the shared comparator input pins will be automatically
disconnected when the corresponding comparator functional pins are selected. As the comparator
inputs approach their switching level, some spurious output signals may be generated on the
comparator output due to the slow rising or falling nature of the input signals. This can be minimised
by the hysteresis function which will apply a small amount of positive feedback to the comparator.
Ideally the comparator should switch at the point where the positive and negative inputs signals are
at the same voltage level. However, unavoidable input offsets introduce some uncertainties here. The
offset calibration function, if executed, will minimize the switching offset value.
• CPC Register
Bit
7
6
5
4
3
2
1
Name
CSEL
CEN
CPOL
COUT
COS
R/W
R/W
R/W
R/W
R
R/W
R/W
R/W
R/W
POR
1
0
0
0
0
0
0
1
CMPEG1 CMPEG0
0
CHYEN
Bit 7 CSEL: Comparator pins or I/O pins selection
0: I/O pin selected
1: Comparator input pin C+ and C- selected
This is the Comparator input pin or I/O pin selection bit. If the bit is high the
comparator input pins will be enabled. As a result, these two pins will lose their I/O
pin functions. Any pull-high configurations associated with the comparator shared pins
will also be automatically disconnected.
Bit 6 CEN: Comparator On/Off control
0: Off
1: On
This is the Comparator on/off control bit. If the bit is zero the comparator will be
switched off and no power consumed even if analog voltages are applied to its inputs.
For power sensitive applications this bit should be cleared to zero if the comparator is
not used or before the device enters the SLEEP or IDLE mode.
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Bit 5 CPOL: Comparator output polarity control
0: Non-invert
1: Invert
This is the comparator polarity control bit. If the bit is zero then the COUT bit will
reflect the non-inverted output condition of the comparator. If the bit is high the
comparator COUT bit will reflect the inverted output condition of the comparator.
Bit 4 COUT: Comparator output bit
CPOL=0
0: C+ < C1: C+ > CCPOL=1
0: C+ > C1: C+ < CThis bit stores the comparator output bit. The polarity of the bit is determined by the
voltages on the comparator inputs and by the condition of the CPOL bit.
Bit 3 COS: Comparator output path selection
0: CX pin – compare output can output to CX pin
1: I/O pin – compare output is only internally used
Bit 2~1 CMPEG1~CMPEG0: Comparator output interrupt edge trigger selection
00: Rising edge – comparator interrupt will be generated if the COUT state changes
from 0 to 1
01: Falling edge – comparator interrupt will be generated if the COUT state changes
from 1 to 0
1x: Both edge – comparator interrupt will be generated if the COUT state changes
from 0 to 1 or 1 to 0
Bit 0 CHYEN: Comparator hysteresis function control
0: Off
1: On
This is the hysteresis control bit and if set high will apply a limited amount of
hysteresis to the comparator, as specified in the Comparator Electrical Characteristics
table. The positive feedback induced by hysteresis reduces the effect of spurious
switching near the comparator threshold.
Comparator Interrupt
The comparator possesses its own interrupt function. When the comparator output changes state,
its relevant interrupt flag will be set, and if the corresponding interrupt enable bit is set, then a jump
to its relevant interrupt vector will be executed. Note that it is the changing state of the COUT bit
and not the output pin which generates an interrupt. If the microcontroller is in the SLEEP or IDLE
Mode and the comparator is enabled, then if the external input lines cause the comparator output bit
to change state, the resulting generated interrupt flag will also generate a wake-up. If it is required to
disable a wake-up from occurring, then the interrupt flag should be first set high before entering the
SLEEP or IDLE Mode.
Programming Considerations
If the comparator is enabled, it will remain active when the microcontroller enters the SLEEP or
IDLE Mode, however as it will consume a certain amount of power, the user may wish to consider
disabling it before the SLEEP or IDLE Mode is entered. As comparator pins are shared with normal
I/O pins the I/O registers for these pins will be read as zero (port control register is “1”) or read as
port data register value (port control register is “0”) if the comparator function is enabled.
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Serial Interface Module – SIM
The device contains a Serial Interface Module, which includes both the four-line SPI interface or
two-line I2C interface types, to allow an easy method of communication with external peripheral
hardware. Having relatively simple communication protocols, these serial interface types allow
the microcontroller to interface to external SPI or I2C based hardware such as sensors, Flash or
EEPROM memory, etc. The SIM interface pins are pin-shared with other I/O pins and therefore the
SIM interface functional pins must first be selected using the pin-remapping selection bits in the IFS
register and the relevant control bit SIMEN bit in the SIMC0 register. As both interface types share
the same pins and registers, the choice of whether the SPI or I2C type is used is made using the SIM
operating mode control bits, named SIM2~SIM0, in the SIMC0 register. These pull-high resistors of
the SIM pin-shared I/O pins except the SCS pin, are selected using pull-high control registers if the
SIM function is enabled and the corresponding pins are used as SIM input pins. Note that if the SCS
pin function is enabled, the corresponding internal pull-high resistor will be disconnected and cannot
be controlled using the pull-high control register.
SPI Interface
The SPI interface is often used to communicate with external peripheral devices such as sensors,
Flash or EEPROM memory devices, etc. Originally developed by Motorola, the four line SPI
interface is a synchronous serial data interface that has a relatively simple communication protocol
simplifying the programming requirements when communicating with external hardware devices.
The communication is full duplex and operates as a slave/master type, where the device can be
either master or slave. Although the SPI interface specification can control multiple slave devices
from a single master, the device provides only one SCS pin. If the master needs to control multiple
slave devices from a single master, the master can use I/O pin to select the slave devices.
SPI Interface Operation
The SPI interface is a full duplex synchronous serial data link. It is a four line interface with pin
names SDI, SDO, SCK and SCS. Pins SDI and SDO are the Serial Data Input and Serial Data
Output lines, SCK is the Serial Clock line and SCS is the Slave Select line. As the SPI interface
pins are pin-shared with normal I/O pins and with the I2C function pins, the SPI interface pins must
first be selected by setting the correct bits in the SIMC0 and SIMC2 registers and the relevant pinremapping control bits. After the desired SPI configuration has been set it can be disabled or enabled
using the SIMEN bit in the SIMC0 register. Communication between devices connected to the SPI
interface is carried out in a slave/master mode with all data transfer initiations being implemented
by the master. The Master also controls the clock signal. As the device only contains a single SCS
pin only one slave device can be utilized. The SCS pin is controlled by software, set CSEN bit to 1
to enable SCS pin function, set CSEN bit to 0 the SCS pin will be floating state.
The SPI function in this device offers the following features:
• Full duplex synchronous data transfer
• Both Master and Slave modes
• LSB first or MSB first data transmission modes
• Transmission complete flag
• Rising or falling active clock edge
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The status of the SPI interface pins is determined by a number of factors such as whether the device
is in the master or slave mode and upon the condition of certain control bits such as CSEN and
SIMEN.
SPI Master
SPI Slave
SCK
SCK
SDO
SDI
SDI
SDO
SCS
SCS
SPI Master/Slave Connection
Data Bus
SIMD
SDI Pin
TX/RX Shift Register
SDO Pin
Clock
Edge/Polarity
Control
CKEG
CKPOLB
Busy
Status
SCK Pin
Clock
Source
Select
fSYS
fSUB
PTM CCRP match frequency/2
SCS Pin
WCOL
TRF
SIMICF
CSEN
SPI Block Diagram
SPI Registers
There are three internal registers which control the overall operation of the SPI interface. These are
the SIMD data register and two registers SIMC0 and SIMC2. Note that the SIMC1 register is only
used by the I2C interface.
Bit
Register
Name
7
6
5
4
SIMC0
SIM2
SIM1
SIM0
—
SIMC2
D7
D6
CKPOLB
CKEG
MLS
SIMD
D7
D6
D5
D4
D3
3
2
1
0
SIMEN
SIMICF
CSEN
WCOL
TRF
D2
D1
D0
SIMDEB1 SIMDEB0
SPI Register List
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SIMD Data Register
The SIMD register is used to store the data being transmitted and received. The same register is used
by both the SPI and I2C functions. Before the device writes data to the SPI bus, the actual data to
be transmitted must be placed in the SIMD register. After the data is received from the SPI bus, the
device can read it from the SIMD register. Any transmission or reception of data from the SPI bus
must be made via the SIMD register.
• SIMD Register
Bit
7
6
5
4
3
2
1
0
Name
D7
D6
D5
D4
D3
D2
D1
D0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
x
x
x
x
x
x
x
x
“x”: unknown
Bit 7~0 D7~D0: SIM data register bit 7 ~ bit 0
SIMD Control Register
There are also two control registers for the SPI interface, SIMC0 and SIMC2. Note that the SIMC2
register also has the name SIMA which is used by the I2C function. The SIMC1 register is not used
by the SPI function, only by the I2C function. The SIMC0 register is used to control the enable/
disable function and to set the data transmission clock frequency. The SIMC2 register is used for
other control functions such as LSB/MSB selection, write collision flag, etc.
• SIMC0 Register
Bit
7
6
5
4
Name
SIM2
SIM1
SIM0
—
3
R/W
R/W
R/W
R/W
—
R/W
POR
1
1
1
—
0
2
1
0
SIMEN
SIMICF
R/W
R/W
R/W
0
0
0
SIMDEB1 SIMDEB0
Bit 7~5 SIM2~SIM0: SIM Operating Mode Control
000: SPI master mode; SPI clock is fSYS/4
001: SPI master mode; SPI clock is fSYS/16
010: SPI master mode; SPI clock is fSYS/64
011: SPI master mode; SPI clock is fSUB
100: SPI master mode; SPI clock is PTM CCRP match frequency/2
101: SPI slave mode
110: I2C slave mode
111: Undefined
These bits setup the overall operating mode of the SIM function. As well as selecting
if the I2C or SPI function, they are used to control the SPI Master/Slave selection and
the SPI Master clock frequency. The SPI clock is a function of the system clock but
can also be chosen to be sourced from PTM and fSUB. If the SPI Slave Mode is selected
then the clock will be supplied by an external Master device.
Bit 4
Unimplemented, read as “0”
Bit 3~2 SIMDEB1~SIMDEB0: I2C Debounce Time Selection
These bits are only available when the SIM is configured to operate in the I2C mode.
Refer to the I2C register section.
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Bit 1 SIMEN: SIM Enable Control
0: Disable
1: Enable
The bit is the overall on/off control for the SIM interface. When the SIMEN bit is
cleared to zero to disable the SIM interface, the SDI, SDO, SCK and SCS, or SDA
and SCL lines will lose their SPI or I2C function and the SIM operating current will be
reduced to a minimum value. When the bit is high the SIM interface is enabled. The
SIM configuration option must have first enabled the SIM interface for this bit to be
effective. If the SIM is configured to operate as an SPI interface via the SIM2~SIM0
bits, the contents of the SPI control registers will remain at the previous settings when
the SIMEN bit changes from low to high and should therefore be first initialised by
the application program. If the SIM is configured to operate as an I2C interface via the
SIM2~SIM0 bits and the SIMEN bit changes from low to high, the contents of the I2C
control bits such as HTX and TXAK will remain at the previous settings and should
therefore be first initialised by the application program while the relevant I2C flags
such as HCF, HAAS, HBB, SRW and RXAK will be set to their default states.
Bit 0 SIMICF: SIM Incomplete Flag
0: SIM incomplete condition not occurred
1: SIM incomplete condition occurred
This bit is only available when the SIM is configured to operate in an SPI slave mode.
If the SPI operates in the slave mode with the SIMEN and CSEN bits both being set
to 1 but the SCS line is pulled high by the external master device before the SPI data
transfer is completely finished, the SIMICF bit will be set to 1 together with the TRF
bit. When this condition occurs, the corresponding interrupt will occur if the interrupt
function is enabled. However, the TRF bit will not be set to 1 if the SIMICF bit is set
to 1 by software application program.
• SIMC2 Register
Bit
7
6
5
4
3
2
1
0
Name
D7
D6
CKPOLB
CKEG
MLS
CSEN
WCOL
TRF
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~6
D7~D6: Undefined bits
These bits can be read or written by the application program.
Bit 5 CKPOLB: SPI clock line base condition selection
0: The SCK line will be high when the clock is inactive
1: The SCK line will be low when the clock is inactive
The CKPOLB bit determines the base condition of the clock line, if the bit is high,
then the SCK line will be low when the clock is inactive. When the CKPOLB bit is
low, then the SCK line will be high when the clock is inactive.
Bit 4 CKEG: SPI SCK clock active edge type selection
CKPOLB=0
0: SCK is high base level and data capture at SCK rising edge
1: SCK is high base level and data capture at SCK falling edge
CKPOLB=1
0: SCK is low base level and data capture at SCK falling edge
1: SCK is low base level and data capture at SCK rising edge
The CKEG and CKPOLB bits are used to setup the way that the clock signal outputs
and inputs data on the SPI bus. These two bits must be configured before data transfer
is executed otherwise an erroneous clock edge may be generated. The CKPOLB bit
determines the base condition of the clock line, if the bit is high, then the SCK line
will be low when the clock is inactive. When the CKPOLB bit is low, then the SCK
line will be high when the clock is inactive. The CKEG bit determines active clock
edge type which depends upon the condition of CKPOLB bit.
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Bit 3 MLS: SPI data shift order
0: LSB first
1: MSB first
This is the data shift select bit and is used to select how the data is transferred, either
MSB or LSB first. Setting the bit high will select MSB first and low for LSB first.
Bit 2 CSEN: SPI SCS pin control
0: Disable
1: Enable
The CSEN bit is used as an enable/disable for the SCS pin. If this bit is low, then the
SCS pin will be disabled and placed into a floating condition. If the bit is high, the
SCS pin will be enabled and used as a select pin.
Bit 1 WCOL: SPI write collision flag
0: No collision
1: Collision
The WCOL flag is used to detect whether a data collision has occurred or not. If this
bit is high, it means that data has been attempted to be written to the SIMD register
during a data transfer operation. This writing operation will be ignored if data is being
transferred. This bit can be cleared to zero by the application program.
Bit 0 TRF: SPI Transmit/Receive complete flag
0: SPI data is being transferred
1: SPI data transfer is completed
The TRF bit is the Transmit/Receive Complete flag and is set to 1 automatically
when an SPI data transfer is completed, but must be cleared to zero by the application
program. It can be used to generate an interrupt.
SPI Communication
After the SPI interface is enabled by setting the SIMEN bit high, then in the Master Mode, when
data is written to the SIMD register, transmission/reception will begin simultaneously. When the data
transfer is complete, the TRF flag will be set automatically, but must be cleared using the application
program. In the Slave Mode, when the clock signal from the master has been received, any data in
the SIMD register will be transmitted and any data on the SDI pin will be shifted into the SIMD
register. The master should output a SCS signal to enable the slave devices before a clock signal
is provided. The slave data to be transferred should be well prepared at the appropriate moment
relative to the SCK signal depending upon the configurations of the CKPOLB bit and CKEG bit.
The accompanying timing diagram shows the relationship between the slave data and SCK signal
for various configurations of the CKPOLB and CKEG bits.
The SPI master mode will continue to function even in the IDLE Mode if the selected SPI clock
source is running.
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SIMEN=1, CSEN=0 (External Pull-high)
SCS
SIMEN, CSEN=1
SCK (CKPOLB=1, CKEG=0)
SCK (CKPOLB=0, CKEG=0)
SCK (CKPOLB=1, CKEG=1)
SCK (CKPOLB=0, CKEG=1)
SDO (CKEG=0)
D7/D0
D6/D1
D5/D2
D4/D3
D3/D4 D2/D5
D1/D6
D0/D7
SDO (CKEG=1)
D7/D0
D6/D1
D5/D2
D4/D3
D3/D4 D2/D5
D1/D6
D0/D7
SDI Data Capture
Write to SIMD
SPI Master Mode Timing
SCS
SCK (CKPOLB=1)
SCK (CKPOLB=0)
SDO
D7/D0
D6/D1
D5/D2
D4/D3
D3/D4
D2/D5
D1/D6
D0/D7
D1/D6
D0/D7
SDI Data Capture
Write to SIMD
(SDO does not change until first SCK edge)
SPI Slave Mode Timing – CKEG=0
SCS
SCK (CKPOLB=1)
SCK (CKPOLB=0)
SDO
D7/D0
D6/D1
D5/D2
D4/D3
D3/D4
D2/D5
SDI Data Capture
Write to SIMD
(SDO changes as soon as writing occurs; SDO is floating if SCS=1)
Note: For SPI slave mode, if SIMEN=1 and CSEN=0, SPI is always
enabled and ignores the SCS level.
SPI Slave Mode Timing – CKEG=1
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SPI Transfer
Master
Master or Slave
?
A
Write Data
into SIMD
Clear WCOL
Slave
Y
SIM[2:0]=000, 001,
010, 011 or 100
WCOL=1?
SIM[2:0]=101
N
N
Configure CKPOLB,
CKEG, CSEN and MLS
Transmission
completed?
(TRF=1?)
Y
SIMEN=1
Read Data
from SIMD
A
Clear TRF
Transfer
finished?
N
Y
END
SPI Transfer Control Flow Chart
SPI Bus Enable/Disable
To enable the SPI bus, set CSEN=1 and SCS=0, then wait for data to be written into the SIMD
(TXRX buffer) register. For the Master Mode, after data has been written to the SIMD (TXRX
buffer) register, then transmission or reception will start automatically. When all the data has been
transferred, the TRF bit should be set. For the Slave Mode, when clock pulses are received on SCK,
data in the TXRX buffer will be shifted out or data on SDI will be shifted in.
When the SPI bus is disabled, SCK, SDI, SDO and SCS can become I/O pins or other pin-shared
functions using the corresponding function control bits.
SPI Operation
All communication is carried out using the 4-line interface for either Master or Slave Mode.
The CSEN bit in the SIMC2 register controls the overall function of the SPI interface. Setting this
bit high will enable the SPI interface by allowing the SCS line to be active, which can then be used
to control the SPI interface. If the CSEN bit is low, the SPI interface will be disabled and the SCS
line will be in a floating condition and can therefore not be used for control of the SPI interface.
If the CSEN bit and the SIMEN bit in the SIMC0 are set high, this will place the SDI line in a
floating condition and the SDO line high. If in Master Mode the SCK line will be either high or low
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depending upon the clock polarity selection bit CKPOLB in the SIMC2 register. If in Slave Mode
the SCK line will be in a floating condition. If the SIMEN bit is low, then the bus will be disabled
and SCS, SDI, SDO and SCK will all become I/O pins or the other functions. In the Master Mode
the Master will always generate the clock signal. The clock and data transmission will be initiated
after data has been written into the SIMD register. In the Slave Mode, the clock signal will be
received from an external master device for both data transmission and reception. The following
sequences show the order to be followed for data transfer in both Master and Slave Mode.
Master Mode
• Step 1
Select the SPI Master mode and clock source using the SIM2~SIM0 bits in the SIMC0 control
register.
• Step 2
Setup the CSEN bit and setup the MLS bit to choose if the data is MSB or LSB first, this setting
must be the same with the Slave devices.
• Step 3
Setup the SIMEN bit in the SIMC0 control register to enable the SPI interface.
• Step 4
For write operations: write the data to the SIMD register, which will actually place the data into
the TXRX buffer. Then use the SCK and SCS lines to output the data. After this, go to step5.
For read operations: the data transferred in on the SDI line will be stored in the TXRX buffer
until all the data has been received at which point it will be latched into the SIMD register.
• Step 5
Check the WCOL bit if set high then a collision error has occurred so return to step 4. If equal to
zero then go to the following step.
• Step 6
Check the TRF bit or wait for a SIM SPI serial bus interrupt.
• Step 7
Read data from the SIMD register.
• Step 8
Clear TRF.
• Step 9
Go to step 4.
Slave Mode
• Step 1
Select the SPI Slave mode using the SIM2~SIM0 bits in the SIMC0 control register
• Step 2
Setup the CSEN bit and setup the MLS bit to choose if the data is MSB or LSB first, this setting
must be the same with the Master devices.
• Step 3
Setup the SIMEN bit in the SIMC0 control register to enable the SPI interface.
• Step 4
For write operations: write the data to the SIMD register, which will actually place the data into
the TXRX buffer. Then wait for the master clock SCK and SCS signal. After this, go to step5.
For read operations: the data transferred in on the SDI line will be stored in the TXRX buffer
until all the data has been received at which point it will be latched into the SIMD register.
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• Step 5
Check the WCOL bit if set high then a collision error has occurred so return to step 4. If equal to
zero then go to the following step.
• Step 6
Check the TRF bit or wait for a SIM SPI serial bus interrupt.
• Step 7
Read data from the SIMD register.
• Step 8
Clear TRF.
• Step 9
Go to step 4.
Error Detection
The WCOL bit in the SIMC2 register is provided to indicate errors during data transfer. The bit is
set by the SPI serial Interface but must be cleared by the application program. This bit indicates a
data collision has occurred which happens if a write to the SIMD register takes place during a data
transfer operation and will prevent the write operation from continuing.
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.
VDD
SDA
SCL
Device
Slave
Device
Master
Device
Slave
I2C Master Slave Bus Connection
I2C interface Operation
The I2C serial interface is a two line interface, a serial data line, SDA, and serial clock line, SCL. As
many devices may be connected together on the same bus, their outputs are both open drain types.
For this reason it is necessary that external pull-high resistors are connected to these outputs. Note
that no chip select line exists, as each device on the I2C bus is identified by a unique address which
will be transmitted and received on the I2C bus.
When two devices communicate with each other on the bidirectional I2C bus, one is known as the
master device and one as the slave device. Both master and slave can transmit and receive data,
however, it is the master device that has overall control of the bus. For the device, 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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Data Bus
I2C Data Register
(SIMD)
fSYS
SCL Pin
SDA Pin
HTX
Debounce
Circuitry
Address Address Match–HAAS
Comparator
Direction Control
Data in MSB
M
U
X
SIMDEB[1:0]
I2C Address Register
(SIMA)
Shift Register
Read/Write Slave
SIM Interrupt
SRW
Data out MSB
TXAK
8-bit Data Transfer Complete–HCF
Transmit/Receive
Control Unit
Detect Start or Stop
SIMTOF
Time-out
Control
fSUB
SIMTOEN
HBB
Address Match
I2C Block Diagram
START signal
from Master
Send slave address
and R/W bit from Master
Acknowledge
from slave
Send data byte
from Master
Acknowledge
from slave
STOP signal
from Master
I2C Interface Operation
The SIMDEB1 and SIMDEB0 bits determine the debounce time of the I2C interface. This uses
the system clock to in effect add a debounce time to the external clock to reduce the possibility
of glitches on the clock line causing erroneous operation. The debounce time, if selected, can be
chosen to be either 2 or 4 system clocks. To achieve the required I2C data transfer speed, there
exists a relationship between the system clock, fSYS, and the I2C debounce time. For either the I2C
Standard or Fast mode operation, users must take care of the selected system clock frequency and
the configured debounce time to match the criterion shown in the following table.
I2C Debounce Time Selection
I2C Standard Mode (100kHz)
I2C Fast Mode (400kHz)
No Devounce
fSYS > 2MHz
fSYS > 5MHz
2 system clock debounce
fSYS > 4MHz
fSYS > 10MHz
fSYS > 8MHz
fSYS > 20MHz
4 system clock debounce
I2C Minimum fSYS Frequency Requirements
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I2C Registers
There are three control registers associated with the I2C bus, SIMC0, SIMC1 and SIMTOC, one
slave address register, SIMA, and one data register, SIMD. Note that the SIMA register also has the
name SIMC2 which is used by the SPI function. Bit SIMEN and bits SIM2~SIM0 in register SIMC0
are used by the I2C interface.
Register
Name
Bit
7
6
5
4
SIMC0
SIM2
SIM1
SIM0
—
SIMC1
HCF
HAAS
HBB
HTX
TXAK
SIMD
D7
D6
D5
D4
D3
SIMA
SIMA6
SIMA5
SIMA4
SIMA3
SIMA2
SIMTOC
SIMTOEN
3
2
1
0
SIMEN
SIMICF
SRW
IAMWU
RXAK
D2
D1
D0
SIMA1
SIMA0
D0
SIMDEB1 SIMDEB0
SIMTOF SIMTOS5 SIMTOS4 SIMTOS3 SIMTOS2 SIMTOS1 SIMTOS0
I2C Register List
I2C Data Register
The SIMD register is used to store the data being transmitted and received. The same register is used
by both the SPI and I2C functions. Before the device writes data to the I2C bus, the actual data to
be transmitted must be placed in the SIMD register. After the data is received from the I2C bus, the
device can read it from the SIMD register. Any transmission or reception of data from the I2C bus
must be made via the SIMD register.
• SIMD Register
Bit
7
6
5
4
3
2
1
0
Name
D7
D6
D5
D4
D3
D2
D1
D0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
x
x
x
x
x
x
x
x
“x”: unknown
Bit 7~0 D7~D0: SIM data register bit 7 ~ bit 0
I2C Address Register
The SIMA register is also used by the SPI interface but has the name SIMC2. The SIMA register is
the location where the 7-bit slave address of the slave device is stored. Bits 7~1 of the SIMA register
define the device slave address. Bit 0 is not defined.
When a master device, which is connected to the I2C bus, sends out an address, which matches the
slave address in the SIMA register, the slave device will be selected. Note that the SIMA register is
the same register address as SIMC2 which is used by the SPI interface.
• SIMA Register
Rev. 1.20
Bit
7
6
5
4
3
2
1
Name
SIMA6
SIMA5
SIMA4
SIMA3
SIMA2
SIMA1
SIMA0
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
SIMA6~SIMA0: I C slave address
SIMA6~SIMA0 is the I2C slave address bit 6~bit 0.
Bit 0
D0: Reserved bit, can be read or written by the application program.
0
2
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I2C Control Register
There are also three control registers for the I2C interface, SIMC0, SIMC1 and SIMTOC. The
register SIMC0 is used to control the enable/disable function and to set the data transmission
clock frequency. The SIMC1 register contains the relevant flags which are used to indicate the I2C
communication status. The SIMTOC register is used to control the I2C bus time-out function which
is described in the I2C Time-out Control section.
• SIMC0 Register
Bit
7
6
5
4
Name
SIM2
SIM1
SIM0
—
3
R/W
R/W
R/W
R/W
—
R/W
POR
1
1
1
—
0
2
1
0
SIMEN
SIMICF
R/W
R/W
R/W
0
0
0
SIMDEB1 SIMDEB0
Bit 7~5 SIM2~SIM0: SIM Operating Mode Control
000: SPI master mode; SPI clock is fSYS/4
001: SPI master mode; SPI clock is fSYS/16
010: SPI master mode; SPI clock is fSYS/64
011: SPI master mode; SPI clock is fSUB
100: SPI master mode; SPI clock is PTM CCRP match frequency/2
101: SPI slave mode
110: I2C slave mode
111: Undefined
These bits setup the overall operating mode of the SIM function. As well as selecting
if the I2C or SPI function, they are used to control the SPI Master/Slave selection and
the SPI Master clock frequency. The SPI clock is a function of the system clock but
can also be chosen to be sourced from PTM and fSUB. If the SPI Slave Mode is selected
then the clock will be supplied by an external Master device.
Bit 4
Unimplemented, read as “0”
Bit 3~2 SIMDEB1~SIMDEB0: I2C Debounce Time Selection
00: No debounce
01: 2 system clock debounce
1x: 4 system clock debounce
These bits are used to select the I2C debounce time when the SIM is configured as the
I2C interface function by setting the SIM2~SIM0 bits to “110”.
Bit 1 SIMEN: SIM Enable Control
0: Disable
1: Enable
The bit is the overall on/off control for the SIM interface. When the SIMEN bit is
cleared to zero to disable the SIM interface, the SDI, SDO, SCK and SCS, or SDA
and SCL lines will lose their SPI or I2C function and the SIM operating current will be
reduced to a minimum value. When the bit is high the SIM interface is enabled. The
SIM configuration option must have first enabled the SIM interface for this bit to be
effective. If the SIM is configured to operate as an SPI interface via the SIM2~SIM0
bits, the contents of the SPI control registers will remain at the previous settings when
the SIMEN bit changes from low to high and should therefore be first initialised by
the application program. If the SIM is configured to operate as an I2C interface via the
SIM2~SIM0 bits and the SIMEN bit changes from low to high, the contents of the I2C
control bits such as HTX and TXAK will remain at the previous settings and should
therefore be first initialised by the application program while the relevant I2C flags
such as HCF, HAAS, HBB, SRW and RXAK will be set to their default states.
Bit 0 SIMICF: SIM Incomplete Flag
This bit is only available when the SIM is configured to operate in an SPI slave mode.
Refer to the SPI register section.
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• SIMC1 Register
Bit
7
6
5
4
3
2
1
0
Name
HCF
HAAS
HBB
HTX
TXAK
SRW
IAMWU
RXAK
R/W
R
R
R
R/W
R/W
R/W
R/W
R
POR
1
0
0
0
0
0
0
1
Bit 7 HCF: I C Bus data transfer completion flag
0: Data is being transferred
1: Completion of an 8-bit data transfer
The HCF flag is the data transfer flag. This flag will be zero when data is being
transferred. Upon completion of an 8-bit data transfer the flag will go high and an
interrupt will be generated.
2
Bit 6 HAAS: I2C Bus address match flag
0: Not address match
1: Address match
The HAAS flag is the address match flag. This flag is used to determine if the slave
device address is the same as the master transmit address. If the addresses match then
this bit will be high, if there is no match then the flag will be low.
Bit 5 HBB: I2C Bus busy flag
0: I2C Bus is not busy
1: I2C Bus is busy
The HBB flag is the I2C busy flag. This flag will be “1” when the I2C bus is busy
which will occur when a START signal is detected. The flag will be set to “0” when
the bus is free which will occur when a STOP signal is detected.
Bit 4 HTX: I2C slave device transmitter/receiver selection
0: Slave device is the receiver
1: Slave device is the transmitter
Bit 3 TXAK: I2C bus transmit acknowledge flag
0: Slave send acknowledge flag
1: Slave does not send acknowledge flag
The TXAK bit is the transmit acknowledge flag. After the slave device receipt of 8-bits
of data, this bit will be transmitted to the bus on the 9th clock from the slave device.
The slave device must always clear the TXAK bit to “0” before further data is received.
Bit 2 SRW: I2C slave read/write flag
0: Slave device should be in receive mode
1: Slave device should be in transmit mode
The SRW flag is the I 2C Slave Read/Write flag. This flag determines whether
the master device wishes to transmit or receive data from the I2C bus. When the
transmitted address and slave address is match, that is when the HAAS flag is set high,
the slave device will check the SRW flag to determine whether it should be in transmit
mode or receive mode. If the SRW flag is high, the master is requesting to read data
from the bus, so the slave device should be in transmit mode. When the SRW flag
is zero, the master will write data to the bus, therefore the slave device should be in
receive mode to read this data.
Bit 1 IAMWU: I2C Address Match Wake-Up control
0: Disable
1: Enable
This bit should be set to 1 to enable the I2C address match wake up from the SLEEP or
IDLE Mode. If the IAMWU bit has been set before entering either the SLEEP or IDLE
mode to enable the I2C address match wake up, then this bit must be cleared to zero by
the application program after wake-up to ensure correction device operation.
Bit 0 RXAK: I2C bus receive acknowledge flag
0: Slave receives acknowledge flag
1: Slave does not receive acknowledge flag
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The RXAK flag is the receiver acknowledge flag. When the RXAK flag is “0”, it
means that a acknowledge signal has been received at the 9th clock, after 8 bits of data
have been transmitted. When the slave device in the transmit mode, the slave device
checks the RXAK flag to determine if the master receiver wishes to receive the next
byte. The slave transmitter will therefore continue sending out data until the RXAK
flag is “1”. When this occurs, the slave transmitter will release the SDA line to allow
the master to send a STOP signal to release the I2C Bus.
I2C Bus Communication
Communication on the I2C bus requires four separate steps, a START signal, a slave device address
transmission, a data transmission and finally a STOP signal. When a START signal is placed on
the I2C bus, all devices on the bus will receive this signal and be notified of the imminent arrival
of data on the bus. The first seven bits of the data will be the slave address with the first bit being
the MSB. If the address of the slave device matches that of the transmitted address, the HAAS bit
in the SIMC1 register will be set and an SIM I2C interrupt will be generated. After entering the
interrupt service routine, the slave device must first check the condition of the HAAS and SIMTOF
bits to determine whether the interrupt source originates from an address match, 8-bit data transfer
completion or I2C bus time-out occurrence. During a data transfer, note that after the 7-bit slave
address has been transmitted, the following bit, which is the 8th bit, is the read/write bit whose
value will be placed in the SRW bit. This bit will be checked by the slave device to determine
whether to go into transmit or receive mode. Before any transfer of data to or from the I2C bus, the
microcontroller must initialise the bus, the following are steps to achieve this:
• Step 1
Set the SIM2~SIM0 bits to “110” and SIMEN bit to “1” in the SIMC0 register to enable the I2C
bus.
• Step 2
Write the slave address of the device to the I2C bus address register SIMA.
• Step 3
Set the SIME interrupt enable bit of the interrupt control register to enable the SIM interrupt.
Start
Set SIM[2:0]=110
Set SIMEN
Write Slave Address
to SIMA
No
Yes
I2C Bus
Interrupt=?
CLR SIME
Poll SIMF to decide when to go
to I2C Bus ISR
SET SIME
Wait for Interrupt
Goto Main Program
Goto Main Program
I2C Bus Initialisation Flow Chart
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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 HBB bit will be set. A START
condition occurs when a high to low transition on the SDA line takes place when the SCL line
remains high.
I2C Slave Address
The transmission of a START signal by the master will be detected by all devices on the I2C bus.
To determine which slave device the master wishes to communicate with, the address of the slave
device will be sent out immediately following the START signal. All slave devices, after receiving
this 7-bit address data, will compare it with their own 7-bit slave address. If the address sent out by
the master matches the internal address of the microcontroller slave device, then an internal SIM
I2C bus interrupt signal will be generated. The next bit following the address, which is the 8th bit,
defines the read/write status and will be saved to the SRW bit of the SIMC1 register. The slave
device will then transmit an acknowledge bit, which is a low level, as the 9th bit. The slave device
will also set the status flag HAAS when the addresses match.
As an SIM I2C bus interrupt signal can come from three sources, when the program enters the
interrupt subroutine, the HAAS and SIMTOF bits should be examined to see whether the interrupt
source has come from a matching slave address, the completion of a data byte transfer or the I2C
bus time-out occurrence. When a slave address is matched, the device must be placed in either
the transmit mode and then write data to the SIMD register, or in the receive mode where it must
implement a dummy read from the SIMD register to release the SCL line.
I2C Bus Read/Write Signal
The SRW bit in the SIMC1 register defines whether the master device wishes to read data from the
I2C bus or write data to the I2C bus. The slave device should examine this bit to determine if it is to
be a transmitter or a receiver. If the SRW flag is “1” then this indicates that the master device wishes
to read data from the I2C bus, therefore the slave device must be setup to send data to the I2C bus as
a transmitter. If the SRW flag is “0” then this indicates that the master wishes to send data to the I2C
bus, therefore the slave device must be setup to read data from the I2C bus as a receiver.
I2C Bus Slave Address Acknowledge Signal
After the master has transmitted a calling address, any slave device on the I 2C bus, whose
own internal address matches the calling address, must generate an acknowledge signal. The
acknowledge signal will inform the master that a slave device has accepted its calling address. If no
acknowledge signal is received by the master then a STOP signal must be transmitted by the master
to end the communication. When the HAAS flag is high, the addresses have matched and the slave
device must check the SRW flag to determine if it is to be a transmitter or a receiver. If the SRW flag
is high, the slave device should be setup to be a transmitter so the HTX bit in the SIMC1 register
should be set to “1”. If the SRW flag is low, then the microcontroller slave device should be setup as
a receiver and the HTX bit in the SIMC1 register should be set to “0”.
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I2C Bus Data and Acknowledge Signal
The transmitted data is 8-bits wide and is transmitted after the slave device has acknowledged
receipt of its slave address. The order of serial bit transmission is the MSB first and the LSB last.
After receipt of 8-bits of data, the receiver must transmit an acknowledge signal, level “0”, before
it can receive the next data byte. If the slave transmitter does not receive an acknowledge bit signal
from the master receiver, then the slave transmitter will release the SDA line to allow the master
to send a STOP signal to release the I2C Bus. The corresponding data will be stored in the SIMD
register. If setup as a transmitter, the slave device must first write the data to be transmitted into the
SIMD register. If setup as a receiver, the slave device must read the transmitted data from the SIMD
register.
When the slave receiver receives the data byte, it must generate an acknowledge bit, known as
TXAK, on the 9th clock. The slave device, which is setup as a transmitter will check the RXAK bit
in the SIMC1 register to determine if it is to send another data byte, if not then it will release the
SDA line and await the receipt of a STOP signal from the master.
SCL
Slave Address
Start
1
SDA
1
0
1
0
1
SRW
ACK
1
0
0
Data
SCL
1
0
0
1
0
ACK
1
0
Stop
0
SDA
S=Start (1 bit)
SA=Slave Address (7 bits)
SR=SRW bit (1 bit)
M=Slave device send acknowledge bit (1 bit)
D=Data (8 bits)
A=ACK (RXAK bit for transmitter, TXAK bit for receiver, 1 bit)
P=Stop (1 bit)
S
SA SR M
D
A
D
A
……
S
SA SR M
D
A
D
A
……
P
I2C Communication Timing Diagram
Note: When a slave address is matched, the device must be placed in either the transmit mode
and then write data to the SIMD register, or in the receive mode where it must implement a
dummy read from the SIMD register to release the SCL line.
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Start
No
No
No
HTX=1?
Yes
HAAS=1?
Yes
SIMTOF=1?
Yes
Yes
SET SIMTOEN
CLR SIMTOF
SRW=1?
No
RETI
Read from SIMD to
release SCL Line
RETI
Yes
SET HTX
CLR HTX
CLR TXAK
Write data to SIMD to
release SCL Line
Dummy read from SIMD
to release SCL Line
RETI
RETI
RXAK=1?
No
CLR HTX
CLR TXAK
Write data to SIMD to
release SCL Line
Dummy read from SIMD
to release SCL Line
RETI
RETI
I2C Bus ISR Flow Chart
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I2C Time-out Control
In order to reduce the I2C lockup problem due to reception of erroneous clock sources, a time-out
function is provided. If the clock source connected to the I2C bus is not received for a while, then the
I2C circuitry and registers will be reset after a certain time-out period. The time-out counter starts
to count on an I2C bus “START” & “address match” condition, and is cleared by an SCL falling
edge. Before the next SCL falling edge arrives, if the time elapsed is greater than the time-out period
specified by the SIMTOC register, then a time-out condition will occur. The time-out function will
stop when an I2C “STOP” condition occurs.
SCL
Start
Slave Address
1
SDA
0
1
1
0
1
SRW
ACK
1
0
0
I2C time-out
counter start
Stop
SCL
1
0
0
1
0
1
0
0
SDA
I2C time-out counter reset
on SCL negative transition
I2C Time-out
When an I2C time-out counter overflow occurs, the counter will stop and the SIMTOEN bit will
be cleared to zero and the SIMTOF bit will be set high to indicate that a time-out condition has
occurred. The time-out condition will also generate an interrupt which uses the SIM interrupt vector.
When an I2C time-out occurs, the I2C internal circuitry will be reset and the registers will be reset
into the following condition:
Registers
After I2C Time-out
SIMD, SIMA, SIMC0
No change
SIMC1
Reset to POR condition
I C Register after Time-out
2
The SIMTOF flag can be cleared by the application program. There are 64 time-out period selections
which can be selected using the SIMTOS bits in the SIMTOC register. The time-out duration is
calculated by the formula: (1~64)×(32/fSUB). This gives a time-out period which ranges from about
1ms to 64ms.
• SIMTOC Register
Bit
Name
7
6
5
4
3
2
1
0
SIMTOEN SIMTOF SIMTOS5 SIMTOS4 SIMTOS3 SIMTOS2 SIMTOS1 SIMTOS0
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 SIMTOEN: SIM I2C Time-out function control
0: Disable
1: Enable
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Bit 6 SIMTOF: SIM I2C Time-out flag
0: No time-out occurred
1: Time-out occurred
This bit is set high when time-out occurs and can only be cleared to zero by application
program.
Bit 5~0 SIMTOS5~SIMTOS0: SIM I2C Time-out period selection
I2C Time-out clock source is fSUB/32.
I2C time-out time is equal to (SIMTOS[5:0]+1)×(32/fSUB).
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
• RX pin wake-up function
• Transmit and receive interrupts
• Interrupts can be initialized by the following conditions:
Rev. 1.20
♦
Transmitter Empty
♦
Transmitter Idle
♦
Receiver Full
♦
Receiver Overrun
♦
Address Mode Detect
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Transmitter Shift Register (TSR)
MSB
…………………………
Receiver Shift Register (RSR)
LSB
TX Pin
TXR_RXR Register
fH
RX Pin
MSB
LSB
TXR_RXR Register
Baud Rate
Generator
Data to be transmitted
…………………………
Buffer
Data received
MCU Data Bus
UART Data Transfer Block Diagram
UART External Pins
To communicate with an external serial interface, the internal UART has two external pins known
as TX and RX. The TX and RX pins are the UART transmitter and receiver pins respectively. The
TX and RX pin function should first be selected by the IFS register before the UART function is
used. Along with the UARTEN bit, the TXEN and RXEN bits, if set, will setup these pins to their
respective TX output and RX input conditions and disable any pull-high resistor option which may
exist on the TX and RX pins. When the TX or RX pin function is disabled by clearing the UARTEN,
TXEN or RXEN bit, the TX or RX pin will be set to a floating state. At this time whether the internal
pull-high resistor is connected to the TX or RX pin or not is determined by the corresponding I/O
pull-high function control bit.
UART Data Transfer Scheme
The above block diagram shows the overall data transfer structure arrangement for the UART. The
actual data to be transmitted from the MCU is first transferred to the TXR_RXR 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_RXR 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 TXR_RXR
register, where it is buffered and can be manipulated by the application program. Only the TXR_
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 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.
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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.
Bit
Register
Name
USR
7
6
5
4
3
2
1
0
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
• 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 7~0 TXRX7~TXRX0: UART Transmit / Receive Data bit 7~bit 0
• 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. Further explanation
on each of the flags is 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 7 PERR: 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 to zero by a software sequence which involves a
read to the status register USR followed by an access to the TXR_RXR data register.
Bit 6 NF: 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 to zero by a software
sequence which will involve a read to the status register USR followed by an access to
the TXR_RXR data register.
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Bit 5 FERR: 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 to zero by a
software sequence which will involve a read to the status register USR followed by an
access to the TXR_RXR data register.
Bit 4 OERR: 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 TXR_RXR receive data register. The flag is cleared to zero by a
software sequence, which is a read to the status register USR followed by an access to
the TXR_RXR data register.
Bit 3 RIDLE: 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 2 RXIF: Receive TXR_RXR data register status
0: TXR_RXR data register is empty
1: TXR_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 TXR_RXR read data register is empty. When the flag is “1”, it
indicates that the TXR_RXR read data register contains new data. When the contents
of the shift register are transferred to the TXR_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 will eventually be cleared to zero when the USR register is
read with RXIF set, followed by a read from the TXR_RXR register, and if the TXR_
RXR register has no more new data available.
Bit 1 TIDLE: Transmission idle
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 high
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 to zero by reading the USR register
with TIDLE set and then writing to the TXR_RXR register. The flag is not generated
when a data character or a break is queued and ready to be sent.
Bit 0 TXIF: Transmit TXR_RXR data register status
0: Character is not transferred to the transmit shift register
1: Character has transferred to the transmit shift register (TXR_RXR 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_RXR data register. The TXIF flag is cleared to zero by reading the
UART status register (USR) with TXIF set and then writing to the TXR_RXR 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.
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• 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
“x”: unknown
Bit 7 UARTEN: UART function enable control
0: Disable UART. TX and RX pins are used as other pin-shared functional pins
1: Enable UART. TX and RX pins can function as UART pins defined by TXEN and
RXEN bits
The UARTEN bit is the UART enable bit. When this bit is equal to “0”, the UART will
be disabled and the RX pin as well as the TX pin will be other pin-shared functional
pins. When the bit is equal to “1”, the UART will be enabled and the TX and RX pins
will function as defined by the TXEN and RXEN enable control bits.
When the UART is disabled, it will empty the buffer so any character remaining in the
buffer will be discarded. In addition, the value of the baud rate counter will be reset. If
the UART is disabled, all error and status flags will be reset. Also the TXEN, RXEN,
TXBRK, RXIF, OERR, FERR, PERR and NF bits will be cleared to zero, while the
TIDLE, TXIF and RIDLE bits will be set high. Other control bits in UCR1, UCR2 and
BRG registers will remain unaffected. If the UART is active and the UARTEN bit is
cleared to zero, 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 6
BNO: 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 5 PREN: Parity function enable control
0: Parity function is disabled
1: Parity function is enabled
This is the parity 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 4 PRT: 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 3 STOPS: 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 are used. If this bit is equal to “0”, then only one stop bit is used.
Bit 2 TXBRK: Transmit break character
0: No break character is transmitted
1: Break characters transmit
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The TXBRK bit is the Transmit Break Character bit. When this bit is “0”, there are
no break characters and the TX pin operates normally. When the bit is “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 1 RX8: 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 0 TX8: 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.
• UCR2 Register
The UCR2 register is the second of the two UART control registers and serves several purposes. One
of its main functions is to control the basic enable/disable operation of 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 enable and the address detect 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 7 TXEN: UART Transmitter enabled 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 will be other pin-shared
functional pin.
If the TXEN bit is equal to “1” and the UARTEN bit is also equal to “1”, the
transmitter will be enabled and the TX pin will be controlled by the UART. Clearing
the TXEN bit during a transmission will cause the data transmission to be aborted and
will reset the transmitter. If this situation occurs, the TX pin will be other pin-shared
functional pin.
Bit 6 RXEN: UART Receiver enabled 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 receive buffers will be reset. In this situation the RX pin will be other pin-shared
functional pin. If the RXEN bit is equal to “1” and the UARTEN bit is also equal
to “1”, the receiver will be enabled and the RX pin will be controlled by the UART.
Clearing the RXEN bit during a reception will cause the data reception to be aborted
and will reset the receiver. If this situation occurs, the RX pin will be other pin-shared
functional pin.
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Bit 5 BRGH: 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 this bit is equal to “1”, the high speed mode is selected. If
the bit is equal to “0”, the low speed mode is selected.
Bit 4 ADDEN: Address detect function enable control
0: Address detect function is disabled
1: Address detect function is enabled
The bit named ADDEN is the address detect function enable control bit. When this
bit is equal to “1”, the address detect 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 BNO. If the address bit known as the 8th or 9th bit of the
received word is “0” with the address detect function being enabled, an interrupt will
not be generated and the received data will be discarded.
Bit 3 WAKE: RX pin wake-up UART function enable control
0: RX pin wake-up UART function is disabled
1: RX pin wake-up UART function is enabled
This bit is used to control the wake-up UART function when a falling edge on the RX
pin occurs. Note that this bit is only available when the UART clock (fH) is switched
off. There will be no RX pin wake-up UART function if the UART clock (fH) exists.
If the WAKE bit is set to 1 as the UART clock (fH) is switched off, a UART wakeup request will be initiated when a falling edge on the RX pin occurs. When this
request happens and the corresponding interrupt is enabled, an RX pin wake-up UART
interrupt will be generated to inform the MCU to wake up the UART function by
switching on the UART clock (fH) via the application program. Otherwise, the UART
function can not resume even if there is a falling edge on the RX pin when the WAKE
bit is cleared to 0.
Bit 2 RIE: Receiver interrupt enable control
0: Receiver related interrupt is disabled
1: Receiver related interrupt is enabled
This bit enables or disables the receiver interrupt. If this bit is equal to “1” and when
the receiver overrun flag OERR or receive 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 1 TIIE: Transmitter Idle interrupt enable control
0: Transmitter idle interrupt is disabled
1: Transmitter idle interrupt is enabled
This 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 0 TEIE: Transmitter Empty interrupt enable control
0: Transmitter empty interrupt is disabled
1: Transmitter empty interrupt is enabled
This bit enables or disables the transmitter empty interrupt. If this bit is equal to “1”
and when the transmitter empty flag TXIF is set, due to a transmitter empty condition,
the UART interrupt request flag will be set. If this bit is equal to “0”, the UART
interrupt request flag will not be influenced by the condition of the TXIF flag.
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• 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 7~0
BRG7~BRG0: Baud Rate values
By programming the BRGH bit in 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.
Note: Baud rate=fH/[64×(N+1)] if BRGH=0;
Baud rate=fH/[16×(N+1)] if BRGH=1.
Baud Rate Generator
To setup the speed of the serial data communication, the UART function contains its own dedicated
baud rate generator. The baud rate is controlled by its own internal free running 8-bit timer, the
period of which is determined by two factors. The first of these is the value placed in the baud rate
register BRG and the second is the value of the BRGH bit with the control register UCR2. 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 N in the BRG
register 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)
fH/[64×(N+1)]
fH / [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.
Calculating the Baud Rate and Error Values
For a clock frequency of 4MHz, and with BRGH cleared to zero 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=fH/[64×(N+1)]
Re-arranging this equation gives N=[fH/(BR×64)]-1
Giving a value for N=[4000000/(4800×64)]-1=12.0208
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=4000000/[64×(12+1)]=4808
Therefore the error is equal to (4808-4800)/4800=0.16%
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UART Setup and Control
For data transfer, the UART function utilizes a non-return-to-zero, more commonly known as NRZ,
format. This is composed of one start bit, eight or nine data bits, and one or two stop bits. Parity
is supported by the UART hardware, and can be setup to be even, odd or no parity. For the most
common data format, 8 data bits along with no parity and one stop bit, denoted as 8, N, 1, is used
as the default setting, which is the setting at power-on. The number of data bits and stop bits, along
with the parity, are setup by programming the corresponding BNO, PRT, PREN, and STOPS bits
in the UCR1 register. The baud rate used to transmit and receive data is setup using the internal
8-bit baud rate generator, while the data is transmitted and received LSB first. Although the UART
transmitter and receiver are functionally independent, they both use the same data format and baud
rate. In all cases stop bits will be used for data transmission.
Enabling/Disabling the UART Interface
The basic on/off function of the internal UART function is controlled using the UARTEN bit in the
UCR1 register. If the UARTEN, TXEN and RXEN bits are set, then these two UART pins will act
as normal TX output pin and RX input pin respectively. If no data is being transmitted on the TX
pin, then it will default to a logic high value.
Clearing the UARTEN bit will disable the TX and RX pins and allow these two pins to be used as
normal 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 error and status flags with bits TXEN, RXEN, TXBRK, RXIF, OERR,
FERR, PERR and NF being cleared while bits TIDLE, TXIF and RIDLE will be set. The remaining
control bits in the UCR1, UCR2 and BRG registers will remain unaffected. If the UARTEN bit in
the UCR1 register is cleared while the UART is active, then all pending transmissions and receptions
will be immediately suspended and the UART will be reset to a condition as defined above. If the
UART is then subsequently re-enabled, it will restart again in the same configuration.
Data, Parity and Stop Bit Selection
The format of the data to be transferred is composed of various factors such as data bit length,
parity on/off, parity type, address bits and the number of stop bits. These factors are determined by
the setup of various bits within the UCR1 register. The BNO bit controls the number of data bits
which can be set to either 8 or 9, the PRT bit controls the choice of odd or even parity, the PREN
bit controls the parity on/off function and 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 bit, which is
the MSB of the data byte, identifies the frame as an address character or data if the address detect
function is enabled. The number of stop bits, which can be either one or two, is independent of the
data length and is only used for the transmitter. There is only one stop bit for the receiver.
Start Bit
Data Bits
Address Bit
Parity Bit
Stop Bit
Example of 8-bit Data Formats
1
8
0
0
1
1
7
0
1
1
1
7
1
0
1
Example of 9-bit Data Formats
1
9
0
0
1
1
8
0
1
1
1
8
1
0
1
Transmitter Receiver Data Format
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The following diagram shows the transmit and receive waveforms for both 8-bit and 9-bit data
formats.
Start
Bit
Parity Bit
Bit 0
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
Bit 7
8-bit Data Format
Start
Bit
Bit 0
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Stop
Bit
Next
Start
Bit
Parity Bit
Bit 6
Bit 7
Bit 8
Stop
Bit
Next
Start
Bit
9-bit Data Format
UART Transmitter
Data word lengths of either 8 or 9 bits can be selected by programming the BNO bit in the UCR1
register. When BNO bit is set, the word length will be set to 9 bits. In this case the 9th bit, which
is the MSB, needs to be stored in the TX8 bit in the UCR1 register. At the transmitter core lies
the Transmitter Shift Register, more commonly known as the TSR, whose data is obtained from
the transmit data register, which is known as the TXR_RXR register. The data to be transmitted
is loaded into this TXR_RXR 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_RXR
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_RXR 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_RXR 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_RXR register will result in an immediate transfer to the TSR. If during a transmission the
TXEN bit is cleared, the transmission will immediately cease and the transmitter will be reset. The
TX output pin will then return to the I/O or other pin-shared function.
Transmitting Data
When the UART is transmitting data, the data is shifted on the TX pin from the shift register, with
the least significant bit first. In the transmit mode, the TXR_RXR register forms a buffer between
the internal bus and the transmitter shift register. It should be noted that if 9-bit data format has been
selected, then the MSB will be taken from the TX8 bit in the UCR1 register. The steps to initiate a
data transfer can be summarized as follows:
• Make the correct selection of the BNO, PRT, PREN and STOPS bits to define the required word
length, parity type and number of stop bits.
• Setup the BRG register to select the desired baud rate.
• Set the TXEN bit to ensure that the 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_RXR 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_RXR
register. Clearing the TXIF flag is always achieved using the following software sequence:
1. A USR register access
2. A TXR_RXR register write execution
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The read-only TXIF flag is set by the UART hardware and if set indicates that the TXR_RXR
register is empty and that other data can now be written into the TXR_RXR 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_RXR register will place the data into the
TXR_RXR 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_RXR register will
place the data directly into the shift register, resulting in the commencement of data transmission,
and the TXIF bit being immediately set. When a frame transmission is complete, which happens
after stop bits are sent or after the break frame, the TIDLE bit will be set. To clear the TIDLE bit the
following software sequence is used:
1. A USR register access
2. A TXR_RXR register write execution
Note that both the TXIF and TIDLE bits are cleared by the same software sequence.
Transmit Break
If the TXBRK bit is set then break characters will be sent on the next transmission. Break character
transmission consists of a start bit, followed by 13×N ‘0’ bits and stop 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 highs at the
end of the last break character will ensure that the start bit of the next frame is recognized.
UART Receiver
The UART is capable of receiving word lengths of either 8 or 9 bits. If the BNO bit is set, the word
length will be set to 9 bits with the MSB being stored in the RX8 bit of the UCR1 register. At the
receiver core lies the Receive Serial Shift Register, 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, LSB first. In the read mode, the TXR_RXR register forms a buffer between the internal bus
and the receiver shift register. The TXR_RXR register is a two byte deep FIFO data buffer, where
two bytes can be held in the FIFO while a third byte can continue to be received. Note that the
application program must ensure that the data is read from TXR_RXR before the third byte has been
completely shifted in, otherwise this 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 BNO, PRT and PREN bits to define the word length, parity type.
• Setup the BRG register to select the desired baud rate.
• Set the RXEN bit to ensure that the RX pin is used as a UART receiver pin.
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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 when the TXR_RXR register has data available.
There will be at most one more character available before an overrun error occurs.
• When the contents of the shift register have been transferred to the TXR_RXR register, then if
the RIE bit is set, an interrupt will be generated.
• If during reception, a frame error, noise error, parity error, or an overrun error has been detected,
then the error flags can be set.
The RXIF bit can be cleared using the following software sequence:
1. A USR register access
2. A TXR_RXR register read execution
Receiving Break
Any break character received by the UART will be managed as a framing error. The receiver will
count and expect a certain number of bit times as specified by the values programmed into the BNO
bit plus one stop bit. 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 plus one stop bit. 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. A break is regarded as a character that contains only zeros with the FERR
flag set. If a long break signal has been detected, the receiver will regard it as a data frame including
a start bit, data bits and the invalid stop bit and the FERR flag will be set. 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. 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, TXR_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, TXR_RXR. An overrun error can also generate an
interrupt if RIE=1.
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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 TXR_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 this third byte has
been entirely shifted in, the data should be read from the TXR_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 TXR_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 TXR_
RXR register.
Noise Error – NF
Over-sampling is used for data recovery to identify valid incoming data and noise. If noise is
detected within a frame the following will occur:
• The read only noise flag, NF, in the USR register will be set on the rising edge of the RXIF bit.
• Data will be transferred from the Shift register to the TXR_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 a TXR_RXR register
read operation.
Framing Error – FERR
The read only framing error flag, FERR, in the USR register, is set if a zero is detected instead of
stop bits. If two stop bits are selected, both stop bits must be high; otherwise the FERR flag will
be set. The FERR flag and the received data will be recorded in the USR and TXR_RXR registers
respectively, and the flag 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 is enabled, PREN=1, and if the parity type,
odd or even is selected. The read only PERR flag and the received data will be recorded in the USR
and TXR_RXR registers respectively. It is cleared on any reset, it should be noted that the flags,
FERR and PERR, in the USR register should first be read by the application program before reading
the data word.
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UART Interrupt Structure
Several individual UART conditions can generate a UART interrupt. When these conditions exist,
a low pulse will be generated to get the attention of the microcontroller. These conditions are a
transmitter data register empty, transmitter idle, receiver data available, receiver overrun, address
detect and an RX pin wake-up. When any of these conditions are created, if the global interrupt
enable bit and its corresponding interrupt control bit are 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 UART
clock (fH) source is switched off and the WAKE and RIE bits in the UCR2 register are set when a
falling edge on the RX pin occurs. Note that in the event of an RX wake-up interrupt occurring,
there will be a certain period of delay, commonly known as the System Start-up Time, for the
oscillator to restart and stabilize before the system resumes normal operation.
Note that the USR register flags are read only and cannot be cleared or set by the application
program, neither will they be cleared when the program jumps to the corresponding interrupt
servicing routine, as is the case for some of the other interrupts. The flags will be cleared
automatically when certain actions are taken by the UART, the details of which are given in the
UART register section. The overall UART interrupt can be disabled or enabled by the related
interrupt enable control bits in the interrupt control registers of the microcontroller to decide whether
the interrupt requested by the UART module is masked out or allowed.
USR Register
UCR2 Register
Transmitter Empty
Flag TXIF
TEIE
Transmitter Idle
Flag TIDLE
TIIE
Receiver Overrun
Flag OERR
RIE
1
WAKE
UART Interrupt
Request Flag
URF
0
1
URE
EMI
Interrupt signal
to MCU
0
1
ADDEN
Receiver Data
Available RXIF
RX Pin
Wake-up
0
0
1
0
1
0
1
RX7 if BNO=0
RX8 if BNO=1
UCR2 Register
UART Interrupt Structure
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Address Detect Mode
Setting the Address Detect Mode bit, ADDEN, in the UCR2 register, enables this special mode. If
this bit is enabled 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 enabled, then when
data is available, an interrupt will only be generated, if the highest received bit has a high value. Note
that the URE and EMI interrupt enable bits must also be enabled for correct interrupt generation.
This highest address bit is the 9th bit if BNO=1 or the 8th bit if BNO=0. If this 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 not enabled, then
a Receiver Data Available interrupt will be generated each time the RXIF flag is set, irrespective of
the data last bit status. The address detect mode and parity enable are mutually exclusive functions.
Therefore if the address detect mode is enabled, then to ensure correct operation, the parity function
should be disabled by resetting the parity enable bit PREN to zero.
ADDEN
Bit 9 if BNO=1,
Bit 8 if BNO=0
UART Interrupt
Generated
0
√
0
1
1
√
0
×
1
√
ADDEN Bit Function
UART Power Down and Wake-up
When the UART clock, fH, is switched off, the UART will cease to function. If the MCU switches
off the UART clock, fH, and 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 switches off the UART clock fH and enters the IDLE
or SLEEP mode by executing the “HALT” instruction while receiving data, then the reception of
data will likewise be paused. When the MCU enters the IDLE or SLEEP mode, note that the USR,
UCR1, UCR2, transmit and receive registers, as well as the BRG register will not be affected. It
is recommended to make sure first that the UART data transmission or reception has been finished
before the microcontroller enters the IDLE or SLEEP 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 when the MCU enters the
power down mode with the UART clock fH being switched off, then a falling edge on the RX pin
will initiate an RX pin wake-up UART interrupt. Note that as it takes certain system clock cycles
after a wake-up, before normal microcontroller operation resumes, any data received during this
time on the RX pin will be ignored.
For a UART wake-up interrupt to occur, in addition to the bits for the wake-up being set, the global
interrupt enable bit, EMI, and the UART interrupt enable bit, URE, must be set. If the EMI and URE
bits are not set then only a wake up event will occur and no interrupt will be generated. Note also
that as it takes certain system clock cycles after a wake-up before normal microcontroller resumes,
the UART interrupt will not be generated until after this time has elapsed.
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SCOM/SSEG Function for LCD
The device has the capability of driving external LCD panels. The common and segment pins for
LCD driving, SCOM0~SCOM5 and SSEG0~SSEG23, are pin-shared with certain pins on the I/O
ports. The LCD signals, COM and SEG, are generated using the application program.
LCD Operation
An external LCD panel can be driven using the device by configuring the I/O pins as common pins
and segment pins. The LCD driver function is controlled using the LCD control registers which in
addition to controlling the overall on/off function also controls the R-type bias current on the SCOM
and SSEG pins. This enables the LCD COM and SEG driver to generate the necessary VSS, (1/3)
VDD, (2/3)VDD and VDD voltage levels for LCD 1/3 bias operation.
The LCDEN bit in the SLCDC0 register is the overall master control for the LCD driver. This bit is
used in conjunction with the COMnEN and SEGmEN bits to select which I/O pins are used for LCD
driving. Note that the corresponding Port Control register does not need to first setup the pins as
outputs to enable the LCD driver operation.
VDD
VDD
COMnEN COMSEGSn
6
6
SCOM0/SSEG0
(2/3) VDD
(1/3) VDD
LCD
COM/SEG
Analog Switch
LCD
Voltage
Select
Circuit
SCOM5/SSEG5
SSEG6
SSEG23
ISEL[1:0]
SEGmEN
LCDEN
FRAME
Note: n=0~5; m=6~23.
Software Controlled LCD Driver Structure
LCD Frames
A cyclic LCD waveform includes two frames known as Frame 0 and Frame 1 for which the
following offers a functional explanation.
Frame 0
To select Frame 0, clear the FRAME bit in the SLCDC0 register to 0.
In frame 0, the COM signal output can have a value of VDD or a VBIAS value of (1/3)×VDD. The SEG
signal output can have a value of VSS or a VBIAS value of (2/3)×VDD.
Frame 1
To select Frame 1, set the FRAME bit in the SLCDC0 register to 1.
In frame 1, the COM signal output can have a value of VSS or a VBIAS value of (2/3)×VDD. The SEG
signal output can have a value of VDD or a VBIAS value of (1/3)×VDD.
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The COMn waveform is controlled by the application program using the FRAME bit in the
SLCDC0 register and the corresponding pin-shared I/O data bit for the respective COM pin to
determine whether the COMn output has a value of VDD, VSS or VBIAS. The SEGm waveform is
controlled in a similar way using the FRAME bit and the corresponding pin-shared I/O data bit for
the respective SEG pin to determine whether the SEGm output has a value of VDD, VSS or VBIAS.
The accompanying waveform diagram shows a typical 1/3 bias LCD waveform generated using the
application program together with the LCD voltage select circuit. Note that the depiction of a “1”
in the diagram illustrates an illuminated LCD pixel. The COM signal polarity generated on pins
SCOM0~SCOM5, whether “0” or “1”, are generated using the corresponding pin-shared I/O data
register bit.
Frame 0
Frame 1
1
COM0
0
0
0
0
Frame 0
0
Frame 1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
1
1
0
0
0
1
1
1
0
0
1
1
0
0
0
1
1
1
1
1
1
VDD
(2/3) VDD
(1/3) VDD
VSS
VDD
(2/3) VDD
(1/3) VDD
VSS
VDD
(2/3) VDD
(1/3) VDD
VSS
VDD
(2/3) VDD
(1/3) VDD
VSS
1
VDD
(2/3) VDD
(1/3) VDD
VSS
1
VDD
(2/3) VDD
(1/3) VDD
VSS
1
1
0
1
0
0
0
1
1
0
1
0
0
1
0
1
1
0
1
0
0
1
1
0
1
0
SEG1
0
1
0
0
1
0
0
1
0
1
SEG0
0
0
1
0
0
1
1
0
0
1
0
0
0
0
0
1
1
0
0
0
1
COM3
0
1
0
0
0
1
0
1
0
0
0
1
1
COM2
0
0
1
0
Frame 0
1
1
0
0
0
1
COM1
0
Frame 0
1
Note: The logical values shown in the above diagram are the corresponding pin-shared I/O data bit value.
1/3 Bias LCD Waveform – 4-COM & 2-SEG Application
LCD Control Registers
The LCD COM and SEG driver enables a range of selections to be provided to suit the requirement
of the LCD panel which is being used. The bias resistor choice is implemented using the ISEL1
and ISEL0 bits in the SLCDC0 register. All COM and SEG pins are pin-shared with I/O pins and
selected as COM and SEG pins using the corresponding pin function selection bits in the SLCDCn
registers respectively.
Bit
Register
Name
7
6
5
4
3
2
1
0
SLCDC0
FRAME
ISEL1
ISEL0
LCDEN
COM3EN
COM2EN
COM1EN
COM0EN
SLCDC1 COM5EN
COM4EN COMSEGS5 COMSEGS4 COMSEGS3 COMSEGS2 COMSEGS1 COMSEGS0
SLCDC2 SEG13EN SEG12EN
SEG11EN
SEG10EN
SEG9EN
SEG8EN
SEG7EN
SEG6EN
SLCDC3 SEG21EN SEG20EN
SEG19EN
SEG18EN
SEG17EN
SEG16EN
SEG15EN
SEG14EN
—
—
—
—
SEG23EN
SEG22EN
SLCDC4
—
—
LCD Driver Control Register List
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• SLCDC0 Register
Bit
7
6
5
4
Name
FRAME
ISEL1
ISEL0
LCDEN
3
2
1
0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
COM3EN COM2EN COM1EN COM0EN
Bit 7 FRAME: SCOM/SSEG Output Frame selection
0: Frame 0
1: Frame 1
Bit 6~5 ISEL1~ISEL0: Select SCOM/SSEG typical bias current (VDD=5V)
00: 8.3μA
01: 16.7μA
10: 50μA
11: 100μA
Bit 4 LCDEN: SCOM/SSEG Module enable control
0: Disable
1: Enable
The SCOMn and SSEGm lines can be enabled using COMnEN and SEGmEN if the
LCDEN bit is set to 1. When the LCD bit is cleared to 0, then the SCOMn and SSEGm
outputs will be fixed at a VSS level.
Bit 3 COM3EN: SCOM3/SSEG3 or other pin function selection
0: Other pin-shared functions
1: SCOM3/SSEG3 function
Bit 2 COM2EN: SCOM2/SSEG2 or other pin function selection
0: Other pin-shared functions
1: SCOM2/SSEG2 function
Bit 1 COM1EN: SCOM1/SSEG1 or other pin function selection
0: Other pin-shared functions
1: SCOM1/SSEG1 function
Bit 0 COM0EN: SCOM0/SSEG0 or other pin function selection
0: Other pin-shared functions
1: SCOM0/SSEG0 function
• SLCDC1 Register
Bit
7
6
5
4
3
2
1
0
Name COM5EN COM4EN COMSEGS5 COMSEGS4 COMSEGS3 COMSEGS2 COMSEGS1 COMSEGS0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7 COM5EN: SCOM5/SSEG5 or other pin function selection
0: Other pin-shared functions
1: SCOM5/SSEG5 function
Bit 6 COM4EN: SCOM4/SSEG4 or other pin function selection
0: Other pin-shared functions
1: SCOM4/SSEG4 function
Bit 5 COMSEGS5: SCOM5 or SSEG5 pin function selection
0: SCOM5
1: SSEG5
Bit 4 COMSEGS4: SCOM4 or SSEG4 pin function selection
0: SCOM4
1: SSEG4
Bit 3 COMSEGS3: SCOM3 or SSEG3 pin function selection
0: SCOM3
1: SSEG3
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Bit 2 COMSEGS2: SCOM2 or SSEG2 pin function selection
0: SCOM2
1: SSEG2
Bit 1 COMSEGS1: SCOM1 or SSEG1 pin function selection
0: SCOM1
1: SSEG1
Bit 0 COMSEGS0: SCOM0 or SSEG0 pin function selection
0: SCOM0
1: SSEG0
• SLCDC2 Register
Bit
Name
7
6
5
4
3
SEG13EN SEG12EN SEG11EN SEG10EN SEG9EN
2
1
0
SEG8EN
SEG7EN
SEG6EN
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
3
2
1
0
Bit 7 SEG13EN: SSEG13 pin function selection
0: Other pin-shared functions
1: SSEG13 function
Bit 6 SEG12EN: SSEG12 pin function selection
0: Other pin-shared functions
1: SSEG12 function
Bit 5 SEG11EN: SSEG11 pin function selection
0: Other pin-shared functions
1: SSEG11 function
Bit 4 SEG10EN: SSEG10 pin function selection
0: Other pin-shared functions
1: SSEG10 function
Bit 3 SEG9EN: SSEG9 pin function selection
0: Other pin-shared functions
1: SSEG9 function
Bit 2 SEG8EN: SSEG8 pin function selection
0: Other pin-shared functions
1: SSEG8 function
Bit 1 SEG7EN: SSEG7 pin function selection
0: Other pin-shared functions
1: SSEG7 function
Bit 0 SEG6EN: SSEG6 pin function selection
0: Other pin-shared functions
1: SSEG6 function
• SLCDC3 Register
Bit
Name
7
6
5
4
SEG21EN SEG20EN SEG19EN SEG18EN SEG17EN SEG16EN SEG15EN SEG14EN
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7 SEG21EN: SSEG21 pin function selection
0: Other pin-shared functions
1: SSEG21 function
Bit 6 SEG20EN: SSEG20 pin function selection
0: Other pin-shared functions
1: SSEG20 function
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Bit 5 SEG19EN: SSEG19 pin function selection
0: Other pin-shared functions
1: SSEG19 function
Bit 4 SEG18EN: SSEG18 pin function selection
0: Other pin-shared functions
1: SSEG18 function
Bit 3 SEG17EN: SSEG17 pin function selection
0: Other pin-shared functions
1: SSEG17 function
Bit 2 SEG16EN: SSEG16 pin function selection
0: Other pin-shared functions
1: SSEG16 function
Bit 1 SEG15EN: SSEG15 pin function selection
0: Other pin-shared functions
1: SSEG15 function
Bit 0 SEG14EN: SSEG14 pin function selection
0: Other pin-shared functions
1: SSEG14 function
• SLCDC4 Register
Bit
7
6
Name
—
—
—
—
R/W
—
—
—
—
POR
—
—
—
—
—
Bit 7~2
5
4
3
2
1
0
—
—
SEG23EN
SEG22EN
—
—
R/W
R/W
—
0
0
Unimplemented, read as “0”
Bit 1 SEG23EN: SSEG23 pin function selection
0: Other pin-shared functions
1: SSEG23 function
Bit 0 SEG22EN: SSEG22 pin function selection
0: Other pin-shared functions
1: SSEG22 function
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 determined. A low voltage condition is indicated when the LVDO
bit is set. If the LVDO bit is low, this indicates that the VDD voltage is above the preset low voltage
value. The LVDEN bit is used to control the overall on/off function of the low voltage detector.
Setting the bit high will enable the low voltage detector. Clearing the bit to zero will switch off the
internal low voltage detector circuits. As the low voltage detector will consume a certain amount of
power, it may be desirable to switch off the circuit when not in use, an important consideration in
power sensitive battery powered applications.
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• 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 4 LVDEN: Low Voltage Detector Enable control
0: Disable
1: Enable
Bit 3
unimplemented, read as “0”
Bit 2~0 VLVD2~VLVD0: LVD Voltage selection
000: 2.0V
001: 2.2V
010: 2.4V
011: 2.7V
100: 3.0V
101: 3.3V
110: 3.6V
111: 4.0V
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. 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.
VDD
VLVD
LVDEN
LVDO
tLVDS
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. 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 wakeup from the SLEEP or IDLE Mode, however if the Low Voltage Detector wake up function is not
required then the LVF flag should be first set high before the device enters the SLEEP or IDLE Mode.
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Interrupts
Interrupts are an important part of any microcontroller system. When an external event or an
internal function such as a Timer Module or an A/D converter requires microcontroller attention,
their corresponding interrupt will enforce a temporary suspension of the main program allowing the
microcontroller to direct attention to their respective needs. The device contains several external
interrupt and internal interrupt functions. The external interrupts are generated by the action of
the external INT0 and INT1 pins, while the internal interrupts are generated by various internal
functions such as TMs, Time Base, LVD, EEPROM, SIM, UART and the A/D converter, etc.
Interrupt Registers
Overall interrupt control, which basically means the setting of request flags when certain microcontroller
conditions occur and the setting of interrupt enable bits by the application program, is controlled by
a series of registers, located in the Special Purpose Data Memory, as shown in the accompanying
table. The registers fall into three categories. The first is the INTC0~INTC2 registers which configure
the primary interrupts, the second is the MFI0~MFI2 registers which configures the Multi-function
interrupts. Finally there is an INTEG register to setup the external interrupt trigger edge type.
Each register contains a number of enable bits to enable or disable individual registers as well as
interrupt flags to indicate the presence of an interrupt request. The naming convention of these
follows a specific pattern. First is listed an abbreviated interrupt type, then the (optional) number of
that interrupt followed by either an “E” for enable/ disable bit or “F” for request flag.
Function
Enable Bit
Request Flag
Notes
EMI
INTnE
CPE
MFnE
ADE
TBnE
SIME
URE
LVE
DEE
CTMPE
CTMAE
STMPE
STMAE
PTMPE
PTMAE
—
INTnF
CPF
MFnF
ADF
TBnF
SIMF
URF
LVF
DEF
CTMPF
CTMAF
STMPF
STMAF
PTMPF
PTMAF
—
n=0 or 1
—
n=0~2
—
n=0 or 1
—
—
—
—
—
—
—
—
—
—
Global
INTn Pins
Comparator
Multi-function
A/D Converter
Time Bases
SIM
UART
LVD
EEPROM Write Operation
CTM
STM
PTM
Interrupt Register Bit Naming Conventions
Bit
Register
Name
7
6
5
4
3
2
1
0
INTEG
—
—
—
—
INT1S1
INT1S0
INT0S1
INT0S0
INTC0
—
MF0F
CPF
INT0F
MF0E
CPE
INT0E
EMI
INTC1
TB0F
ADF
MF2F
MF1F
TB0E
ADE
MF2E
MF1E
INTC2
URF
SIMF
INT1F
TB1F
URE
SIME
INT1E
TB1E
MFI0
—
—
STMAF
STMPF
—
—
STMAE
STMPE
MFI1
CTMAF
CTMPF
PTMAF
PTMPF
CTMAE
CTMPE
PTMAE
PTMPE
MFI2
—
—
DEF
LVF
—
—
DEE
LVE
Interrupt Register List
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• INTEG Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
INT1S1
INT1S0
INT0S1
INT0S0
R/W
—
—
—
—
R/W
R/W
R/W
R/W
POR
—
—
—
—
0
0
0
0
0
Bit 7~4
Unimplemented, read as “0”
Bit 3~2 INT1S1~INT1S0: Interrupt edge control for INT1 pin
00: Disable
01: Rising edge
10: Falling edge
11: Rising and falling edges
Bit 1~0 INT0S1~INT0S0: Interrupt edge control for INT0 pin
00: Disable
01: Rising edge
10: Falling edge
11: Rising and falling edges
• INTC0 Register
Bit
7
6
5
4
3
2
1
Name
—
MF0F
CPF
INT0F
MF0E
CPE
INT0E
EMI
R/W
—
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
—
0
0
0
0
0
0
0
Bit 7
Unimplemented, read as “0”
Bit 6 MF0F: Multi-function 0 interrupt request flag
0: No request
1: Interrupt request
Bit 5
CPF: Comparator interrupt request flag
0: No request
1: Interrupt request
Bit 4
INT0F: INT0 interrupt request flag
0: No request
1: Interrupt request
Bit 3
MF0E: Multi-function 0 interrupt control
0: Disable
1: Enable
Bit 2
CPE: Comparator interrupt control
0: Disable
1: Enable
Bit 1
INT0E: INT0 interrupt control
0: Disable
1: Enable
Bit 0 EMI: Global interrupt control
0: Disable
1: Enable
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• INTC1 Register
Bit
7
6
5
4
3
2
1
0
Name
TB0F
ADF
MF2F
MF1F
TB0E
ADE
MF2E
MF1E
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7
TB0F: Time Base 0 interrupt request flag
0: No request
1: Interrupt request
Bit 6
ADF: A/D Converter interrupt request flag
0: No request
1: Interrupt request
Bit 5
MF2F: Multi-function 2 interrupt request flag
0: No request
1: Interrupt request
Bit 4
MF1F: Multi-function 1 interrupt request flag
0: No request
1: Interrupt request
Bit 3
TB0E: Time Base 0 interrupt control
0: Disable
1: Enable
Bit 2
ADE: A/D Converter interrupt control
0: Disable
1: Enable
Bit 1
MF2E: Multi-function 2 interrupt control
0: Disable
1: Enable
Bit 0
MF1E: Multi-function 1 interrupt control
0: Disable
1: Enable
• INTC2 Register
Rev. 1.20
Bit
7
6
5
4
3
2
1
0
Name
URF
SIMF
INT1F
TB1F
URE
SIME
INT1E
TB1E
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7
URF: UART interrupt request flag
0: No request
1: Interrupt request
Bit 6
SIMF: SIM interrupt request flag
0: No request
1: Interrupt request
Bit 5
INT1F: INT1 interrupt 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
URE: UART interrupt control
0: Disable
1: Enable
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Bit 2
SIME: SIM interrupt control
0: Disable
1: Enable
Bit 1
INT1E: INT1 interrupt control
0: Disable
1: Enable
Bit 0
TB1E: Time Base 1 interrupt control
0: Disable
1: Enable
• MFI0 Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
STMAF
STMPF
—
—
STMAE
STMPE
R/W
—
—
R/W
R/W
—
—
R/W
R/W
POR
—
—
0
0
—
—
0
0
Bit 7~6
Unimplemented, read as “0”
Bit 5
STMAF: STM Comparator A match interrupt request flag
0: No request
1: Interrupt request
Bit 4
STMPF: STM Comparator P match interrupt request flag
0: No request
1: Interrupt request
Bit 3~2
Unimplemented, read as “0”
Bit 1
STMAE: STM Comparator A match interrupt control
0: Disable
1: Enable
Bit 0
STMPE: STM Comparator P match interrupt control
0: Disable
1: Enable
• MFI1 Register
Rev. 1.20
Bit
7
6
5
4
3
2
1
0
Name
CTMAF
CTMPF
PTMAF
PTMPF
CTMAE
CTMPE
PTMAE
PTMPE
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
CTMAF: CTM Comparator A match interrupt request flag
0: No request
1: Interrupt request
Bit 6
CTMPF: CTM Comparator P match interrupt request flag
0: No request
1: Interrupt request
Bit 5
PTMAF: PTM Comparator A match interrupt request flag
0: No request
1: Interrupt request
Bit 4
PTMPF: PTM Comparator P match interrupt request flag
0: No request
1: Interrupt request
Bit 3
CTMAE: CTM Comparator A match interrupt control
0: Disable
1: Enable
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Bit 2
CTMPE: CTM Comparator P match interrupt control
0: Disable
1: Enable
Bit 1
PTMAE: PTM Comparator A match interrupt control
0: Disable
1: Enable
Bit 0
PTMPE: PTM Comparator P match interrupt control
0: Disable
1: Enable
• 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 or Comparator A
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,
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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.
If an interrupt requires immediate servicing while the program is already in another interrupt service
routine, the EMI bit should be set after entering the routine, to allow interrupt nesting. If the stack
is full, the interrupt request will not be acknowledged, even if the related interrupt is enabled, until
the Stack Pointer is decremented. If immediate service is desired, the stack must be prevented from
becoming full. In case of simultaneous requests, the accompanying diagram shows the priority that
is applied. All of the interrupt request flags when set will wake-up the device if it is in SLEEP or
IDLE Mode, however to prevent a wake-up from occurring the corresponding flag should be set
before the device is in SLEEP or IDLE Mode.
Legend
EMI auto disabled in ISR
xxF
Request Flag, no auto reset in ISR
xxF
Request Flag, auto reset in ISR
xxE
Enable Bits
Interrupts contained within MultiFunction Interrupts
STM P
STMPF
STMPE
STM A
STMAF
STMAE
PTM P
PTMPF
PTMPE
PTM A
PTMAF
PTMAE
CTM P
CTMPF
CTMPE
CTM A
CTMAF
CTMAE
LVD
LVF
LVE
EEPROM
DEF
DEE
Interrupt Name
Request
Flags
Enable Bits
Master
Enable
Vector
Priority
INT0 Pin
INT0F
INT0E
EMI
04H
High
Comparator
CPF
CPE
EMI
08H
M. Funct. 0
MF0F
MF0E
EMI
0CH
M. Funct. 1
MF1F
MF1E
EMI
10H
M. Funct. 2
MF2F
MF2E
EMI
14H
A/D
ADF
ADE
EMI
18H
Time Base 0
TB0F
TB0E
EMI
1CH
Time Base 1
TB1F
TB1E
EMI
20H
INT1 Pin
INT1F
INT1E
EMI
24H
SIM
SIMF
SIME
EMI
28H
UART
URF
URE
EMI
2CH
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
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external interrupt request flags, INT0F~INT1F, will be automatically reset and the EMI bit will be
automatically cleared to disable other interrupts. Note that any pull-high resistor selections on the
external interrupt pins will remain valid even if the pin is used as an external interrupt input.
The INTEG register is used to select the type of active edge that will trigger the external interrupt.
A choice of either rising or falling or both edge types can be chosen to trigger an external interrupt.
Note that the INTEG register can also be used to disable the external interrupt function.
Comparator Interrupt
The comparator interrupt is controlled by the internal comparator. A comparator interrupt request
will take place when the comparator interrupt request flag, CPF, is set, a situation that will occur
when the comparator output bit changes state. To allow the program to branch to its respective
interrupt vector address, the global interrupt enable bit, EMI, and comparator interrupt enable bit,
CPE, must first be set. When the interrupt is enabled, the stack is not full and the comparator inputs
generate a comparator output transition, a subroutine call to the comparator interrupt vector, will
take place. When the interrupt is serviced, the comparator interrupt request flag will be automatically
reset and the EMI bit will be automatically cleared to disable other interrupts.
Multi-function Interrupts
Within the device there are three Multi-function interrupts. Unlike the other independent interrupts,
these interrupts have no independent source, but rather are formed from other existing interrupt
sources, namely the TM interrupts, LVD interrupt and EEPROM write operation interrupt.
A Multi-function interrupt request will take place when any of the Multi-function interrupt request
flags MFnF are set. The Multi-function interrupt flag 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 any one of the
interrupts contained within each of the Multi-function interrupt occurs, a subroutine call to the
related Multi-function interrupt vector 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 request flags will be
automatically reset when the interrupt is serviced, the request flags from the original source of
the Multi-function interrupt will not be automatically reset and must be manually reset by the
application program.
A/D Converter Interrupt
The A/D Converter Interrupt is controlled by the termination of an A/D conversion process. An
A/D Converter Interrupt request will take place when the A/D Converter Interrupt request flag, ADF,
is set, which occurs when the A/D conversion process finishes. To allow the program to branch to its
respective interrupt vector address, the global interrupt enable bit, EMI, and A/D Interrupt enable bit,
ADE, must first be set. When the interrupt is enabled, the stack is not full and the A/D conversion
process has ended, a subroutine call to the A/D Converter Interrupt vector, will take place. When the
interrupt is serviced, the A/D Converter Interrupt flag, ADF, will be automatically cleared. The EMI
bit will also be automatically cleared to disable other interrupts.
Time Base Interrupts
The function of the Time Base Interrupt is to provide regular time signal in the form of an internal
interrupt. They are controlled by the overflow signals from their respective timer functions. When
these happen their respective interrupt request flags, TB0F or TB1F, will be set. To allow the
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program to branch to their respective interrupt vector addresses, the global interrupt enable bit, EMI
and Time Base enable bit, TB0E or TB1E, must first be set. When the interrupt is enabled, the stack
is not full and the Time Base overflows, a subroutine call to their respective vector locations will
take place. When the interrupt is serviced, the respective interrupt request flag, TB0F or TB1F, will
be automatically reset and the EMI bit will be cleared to disable other interrupts.
The purpose of the Time Base Interrupt is to provide an interrupt signal at fixed time periods. Their
clock sources originate from the internal clock source fTB. This fTB input clock passes through a
divider, the division ratio of which is selected by programming the appropriate bits in the TBC
register to obtain longer interrupt periods whose value ranges. The clock source that generates fTB,
which in turn controls the Time Base interrupt period, can originate from several different sources,
as shown in the System Operating Mode section.
fTBC
M
U
X
fSYS/4
M
U
X
fTB/28 ~ fTB/215
Prescaler
fTB
Time Base 0 Interrupt
TB02~TB00
M
U
X
12
Prescaler
TBCK
fTB/2 ~ fTB/215
Time Base 1 Interrupt
TB11~TB10
Time Base Interrupts
• 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 function enable control
0: Disable
1: Enable
Bit 6 TBCK: Time Base clock source selection
0: fTBC
1: fSYS/4
Bit 5~4 TB11~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 slow start-up
Bit 2~0 TB02~TB00: Time Base 0 time-out period selection
000: 28/fTB
001: 29/fTB
010: 210/fTB
011: 211/fTB
100: 212/fTB
101: 213/fTB
110: 214/fTB
111: 215/fTB
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Serial Interface Module Interrupt
The Serial Interface Module Interrupt, also known as the SIM interrupt, is controlled by the SPI or
I2C data transfer. A SIM Interrupt request will take place when the SIM Interrupt request flag, SIMF,
is set, which occurs when a byte of data has been received or transmitted by the SIM interface,
an I2C slave address match or I2C bus time-out occurrence. To allow the program to branch to its
respective interrupt vector address, the global interrupt enable bit, EMI and the Serial Interface
Interrupt enable bit, SIME, must first be set. When the interrupt is enabled, the stack is not full
and any of the above described situations occurs, a subroutine call to the respective SIM Interrupt
vector, will take place. When the Serial Interface Interrupt is serviced, the SIMF flag will also be
automatically cleared. The EMI bit will also be automatically cleared to disable other interrupts.
UART Transfer Interrupt
The UART Transfer Interrupt is controlled by several UART transfer conditions. When one of these
conditions occurs, an interrupt pulse will be generated to get the attention of the microcontroller.
These conditions are a transmitter data register empty, transmitter idle, receiver data available,
receiver overrun, address detect and an RX pin wake-up. To allow the program to branch to its
respective interrupt vector address, the global interrupt enable bit, EMI, and UART Interrupt
enable bit, URE, must first be set. When the interrupt is enabled, the stack is not full and any of the
conditions described above occurs, a subroutine call to the UART Interrupt vector, will take place.
When the interrupt is serviced, the UART Interrupt flag, URF, will be automatically cleared. The
EMI bit will also be automatically cleared to disable other interrupts.
LVD Interrupt
The Low Voltage Detector Interrupt is contained within the Multi-function Interrupt. An LVD
Interrupt request will take place when the LVD Interrupt request flag, LVF, is set, which occurs
when the Low Voltage Detector function detects a low power supply voltage. To allow the program
to branch to its respective interrupt vector address, the global interrupt enable bit, EMI, Low Voltage
Interrupt enable bit, LVE, and associated Multi-function interrupt enable bit, must first be set. When
the interrupt is enabled, the stack is not full and a low voltage condition occurs, a subroutine call to
the Multi-function Interrupt vector, will take place. When the Low Voltage Interrupt is serviced, the
EMI bit will be automatically cleared to disable other interrupts. However, only the Multi-function
interrupt request flag will be also automatically cleared. As the LVF flag will not be automatically
cleared, it has to be cleared by the application program.
EEPROM Write Interrupt
The EEPROM Write Interrupt is contained within the Multi-function Interrupt. An EEPROM
Write Interrupt request will take place when the EEPROM Write Interrupt request flag, DEF, is set,
which occurs when an EEPROM Write cycle ends. To allow the program to branch to its respective
interrupt vector address, the global interrupt enable bit, EMI, EEPROM Write Interrupt enable bit,
DEE, and associated Multi-function interrupt enable bit must first be set. When the interrupt is
enabled, the stack is not full and an EEPROM Write cycle ends, a subroutine call to the respective
Multi-function Interrupt vector will take place. When the EEPROM Write Interrupt is serviced, the
EMI bit will be automatically cleared to disable other interrupts. However, only the Multi-function
interrupt request flag will be automatically cleared. As the DEF flag will not be automatically
cleared, it has to be cleared by the application program.
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Timer Module Interrupts
The Compact, Standard and Periodic TMs have two interrupts, one comes from the comparator A
match situation and the other comes from the comparator P match situation. All of the TM interrupts
are contained within the Multi-function Interrupts. For all of the TM types there are two interrupt
request flags and two enable control bits. A TM interrupt request will take place when any of the TM
request flags are set, a situation which occurs when a TM comparator P or A match situation happens.
To allow the program to branch to its respective interrupt vector address, the global interrupt enable
bit, EMI, respective TM Interrupt enable bit, and relevant Multi-function Interrupt enable bit, MFnE,
must first be set. When the interrupt is enabled, the stack is not full and a TM comparator match
situation occurs, a subroutine call to the relevant Multi-function Interrupt vector locations, will take
place. When the TM interrupt is serviced, the EMI bit will be automatically cleared to disable other
interrupts. However, only the related MFnF flag will be automatically cleared. As the TM interrupt
request flags will not be automatically cleared, they have to be cleared by the application program.
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.
Programming Considerations
By disabling the relevant interrupt enable bits, a requested interrupt can be prevented from being
serviced, however, once an interrupt request flag is set, it will remain in this condition in the
interrupt register until the corresponding interrupt is serviced or until the request flag is cleared by
the application program.
Where a certain interrupt is contained within a Multi-function interrupt, then when the interrupt
service routine is executed, as only the Multi-function interrupt request flags, MFnF, will be
automatically cleared, the individual request flag for the function needs to be cleared by the
application program.
It is recommended that programs do not use the “CALL” instruction within the interrupt service
subroutine. Interrupts often occur in an unpredictable manner or need to be serviced immediately.
If only one stack is left and the interrupt is not well controlled, the original control sequence will be
damaged once a CALL subroutine is executed in the interrupt subroutine.
Every interrupt has the capability of waking up the microcontroller when it is in 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.
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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.
Configuration Options
Configuration options refer to certain options within the MCU that are programmed into the device
during the programming process. During the development process, these options are selected using
the HT-IDE software development tools. As these options are programmed into the device using
the hardware programming tools, once they are selected they cannot be changed later using the
application program. All options must be defined for proper system function, the details of which are
shown in the table.
No.
Options
1
High Speed System Oscillator Selection – fH: HXT or HIRC
2
Low Speed System Oscillator Selection – fSUB: LXT or LIRC
3
HIRC Frequency Selection – fHIRC: 8MHz, 12MHz or 16MHz
Application Circuits
VDD
SCOMn
VDD
SSEGm
0.1µF
LCD Panel
SCS/SCK
SDO/SDI
VSS
SDA/SCL
TX/RX
See Oscillator
Section
OSC
Circuit
PC0/OSC1
PC1/OSC2
C+/C-/CX
AN0~AN11
PA0~PA7
OSC
Circuit
PB0/XT1
PB1/XT2
See Oscillator
Section
Rev. 1.20
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PC0~PC6
PD0~PD3
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Instruction Set
Introduction
Central to the successful operation of any microcontroller is its instruction set, which is a set of
program instruction codes that directs the microcontroller to perform certain operations. In the case
of Holtek microcontroller, a comprehensive and flexible set of over 60 instructions is provided to
enable programmers to implement their application with the minimum of programming overheads.
For easier understanding of the various instruction codes, they have been subdivided into several
functional groupings.
Instruction Timing
Most instructions are implemented within one instruction cycle. The exceptions to this are branch,
call, or table read instructions where two instruction cycles are required. One instruction cycle is
equal to 4 system clock cycles, therefore in the case of an 8MHz system oscillator, most instructions
would be implemented within 0.5μs and branch or call instructions would be implemented within
1μs. Although instructions which require one more cycle to implement are generally limited to
the JMP, CALL, RET, RETI and table read instructions, it is important to realize that any other
instructions which involve manipulation of the Program Counter Low register or PCL will also take
one more cycle to implement. As instructions which change the contents of the PCL will imply a
direct jump to that new address, one more cycle will be required. Examples of such instructions
would be "CLR PCL" or "MOV PCL, A". For the case of skip instructions, it must be noted that if
the result of the comparison involves a skip operation then this will also take one more cycle, if no
skip is involved then only one cycle is required.
Moving and Transferring Data
The transfer of data within the microcontroller program is one of the most frequently used
operations. Making use of 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 Operation
The standard logical operations such as AND, OR, XOR and CPL all have their own instruction
within the Holtek microcontroller instruction set. As with the case of most instructions involving
data manipulation, data must pass through the Accumulator which may involve additional
programming steps. In all logical data operations, the zero flag may be set if the result of the
operation is zero. Another form of logical data manipulation comes from the rotate instructions such
as RR, RL, RRC and RLC which provide a simple means of rotating one bit right or left. Different
rotate instructions exist depending on program requirements. Rotate instructions are useful for serial
port programming applications where data can be rotated from an internal register into the Carry
bit from where it can be examined and the necessary serial bit set high or low. Another application
which rotate data operations are used is to implement multiplication and division calculations.
Branches and Control Transfer
Program branching takes the form of either jumps to specified locations using the JMP instruction
or to a subroutine using the CALL instruction. They differ in the sense that in the case of a
subroutine call, the program must return to the instruction immediately when the subroutine has
been carried out. This is done by placing a return instruction "RET" in the subroutine which will
cause the program to jump back to the address right after the CALL instruction. In the case of a JMP
instruction, the program simply jumps to the desired location. There is no requirement to jump back
to the original jumping off point as in the case of the CALL instruction. One special and extremely
useful set of branch instructions are the conditional branches. Here a decision is first made regarding
the condition of a certain data memory or individual bits. Depending upon the conditions, the
program will continue with the next instruction or skip over it and jump to the following instruction.
These instructions are the key to decision making and branching within the program perhaps
determined by the condition of certain input switches or by the condition of internal data bits.
Bit Operations
The ability to provide single bit operations on Data Memory is an extremely flexible feature of all
Holtek microcontrollers. This feature is especially useful for output port bit programming where
individual bits or port pins can be directly set high or low using either the "SET [m].i" or "CLR [m].i"
instructions respectively. The feature removes the need for programmers to first read the 8-bit output
port, manipulate the input data to ensure that other bits are not changed and then output the port with
the correct new data. This read-modify-write process is taken care of automatically when these bit
operation instructions are used.
Table Read Operations
Data storage is normally implemented by using registers. However, when working with large
amounts of fixed data, the volume involved often makes it inconvenient to store the fixed data in
the Data Memory. To overcome this problem, Holtek microcontrollers allow an area of Program
Memory to be set as a table where data can be directly stored. A set of easy to use instructions
provides the means by which this fixed data can be referenced and retrieved from the Program
Memory.
Other Operations
In addition to the above functional instructions, a range of other instructions also exist such as
the "HALT" instruction for Power-down operations and instructions to control the operation of
the Watchdog Timer for reliable program operations under extreme electric or electromagnetic
environments. For their relevant operations, refer to the functional related sections.
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Instruction Set Summary
The following table depicts a summary of the instruction set categorised according to function and
can be consulted as a basic instruction reference using the following listed conventions.
Table Conventions
x: Bits immediate data
m: Data Memory address
A: Accumulator
i: 0~7 number of bits
addr: Program memory address
Mnemonic
Description
Cycles
Flag Affected
Add Data Memory to ACC
Add ACC to Data Memory
Add immediate data to ACC
Add Data Memory to ACC with Carry
Add ACC to Data memory with Carry
Subtract immediate data from the ACC
Subtract Data Memory from ACC
Subtract Data Memory from ACC with result in Data Memory
Subtract Data Memory from ACC with Carry
Subtract Data Memory from ACC with Carry, result in Data Memory
Decimal adjust ACC for Addition with result in Data Memory
1
1Note
1
1
1Note
1
1
1Note
1
1Note
1Note
Z, C, AC, OV
Z, C, AC, OV
Z, C, AC, OV
Z, C, AC, OV
Z, C, AC, OV
Z, C, AC, OV
Z, C, AC, OV
Z, C, AC, OV
Z, C, AC, OV
Z, C, AC, OV
C
1
1
1
1Note
1Note
1Note
1
1
1
1Note
1
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Increment Data Memory with result in ACC
Increment Data Memory
Decrement Data Memory with result in ACC
Decrement Data Memory
1
1Note
1
1Note
Z
Z
Z
Z
Rotate Data Memory right with result in ACC
Rotate Data Memory right
Rotate Data Memory right through Carry with result in ACC
Rotate Data Memory right through Carry
Rotate Data Memory left with result in ACC
Rotate Data Memory left
Rotate Data Memory left through Carry with result in ACC
Rotate Data Memory left through Carry
1
1Note
1
1Note
1
1Note
1
1Note
None
None
C
C
None
None
C
C
Arithmetic
ADD A,[m]
ADDM A,[m]
ADD A,x
ADC A,[m]
ADCM A,[m]
SUB A,x
SUB A,[m]
SUBM A,[m]
SBC A,[m]
SBCM A,[m]
DAA [m]
Logic Operation
AND A,[m]
OR A,[m]
XOR A,[m]
ANDM A,[m]
ORM A,[m]
XORM A,[m]
AND A,x
OR A,x
XOR A,x
CPL [m]
CPLA [m]
Logical AND Data Memory to ACC
Logical OR Data Memory to ACC
Logical XOR Data Memory to ACC
Logical AND ACC to Data Memory
Logical OR ACC to Data Memory
Logical XOR ACC to Data Memory
Logical AND immediate Data to ACC
Logical OR immediate Data to ACC
Logical XOR immediate Data to ACC
Complement Data Memory
Complement Data Memory with result in ACC
Increment & Decrement
INCA [m]
INC [m]
DECA [m]
DEC [m]
Rotate
RRA [m]
RR [m]
RRCA [m]
RRC [m]
RLA [m]
RL [m]
RLCA [m]
RLC [m]
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Mnemonic
Description
Cycles
Flag Affected
Move Data Memory to ACC
Move ACC to Data Memory
Move immediate data to ACC
1
1Note
1
None
None
None
Clear bit of Data Memory
Set bit of Data Memory
1Note
1Note
None
None
Jump unconditionally
Skip if Data Memory is zero
Skip if Data Memory is zero with data movement to ACC
Skip if bit i of Data Memory is zero
Skip if bit i of Data Memory is not zero
Skip if increment Data Memory is zero
Skip if decrement Data Memory is zero
Skip if increment Data Memory is zero with result in ACC
Skip if decrement Data Memory is zero with result in ACC
Subroutine call
Return from subroutine
Return from subroutine and load immediate data to ACC
Return from interrupt
2
1Note
1Note
1Note
1Note
1Note
1Note
1Note
1Note
2
2
2
2
None
None
None
None
None
None
None
None
None
None
None
None
None
Read table (specific page or current page) to TBLH and Data Memory
Read table (last page) to TBLH and Data Memory
2Note
2Note
None
None
No operation
Clear Data Memory
Set Data Memory
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
1Note
1
1
None
None
None
TO, PDF
None
None
TO, PDF
Data Move
MOV A,[m]
MOV [m],A
MOV A,x
Bit Operation
CLR [m].i
SET [m].i
Branch Operation
JMP addr
SZ [m]
SZA [m]
SZ [m].i
SNZ [m].i
SIZ [m]
SDZ [m]
SIZA [m]
SDZA [m]
CALL addr
RET
RET A,x
RETI
Table Read Operation
TABRD [m]
TABRDL [m]
Miscellaneous
NOP
CLR [m]
SET [m]
CLR WDT
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.
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Instruction Definition
ADC A,[m]
Description
Operation
Affected flag(s)
Add Data Memory to ACC with Carry
The contents of the specified Data Memory, Accumulator and the carry flag are added.
The result is stored in the Accumulator.
ACC ← ACC + [m] + C
OV, Z, AC, C
ADCM A,[m]
Description
Operation
Affected flag(s)
Add ACC to Data Memory with Carry
The contents of the specified Data Memory, Accumulator and the carry flag are added.
The result is stored in the specified Data Memory.
[m] ← ACC + [m] + C
OV, Z, AC, C
Add Data Memory to ACC
ADD A,[m]
Description
The contents of the specified Data Memory and the Accumulator are added.
The result is stored in the Accumulator.
Operation
Affected flag(s)
ACC ← ACC + [m]
OV, Z, AC, C
ADD A,x
Description
Operation
Affected flag(s)
Add immediate data to ACC
The contents of the Accumulator and the specified immediate data are added.
The result is stored in the Accumulator.
ACC ← ACC + x
OV, Z, AC, C
ADDM A,[m]
Description
Operation
Affected flag(s)
Add ACC to Data Memory
The contents of the specified Data Memory and the Accumulator are added.
The result is stored in the specified Data Memory.
[m] ← ACC + [m]
OV, Z, AC, C
AND A,[m]
Description
Operation
Affected flag(s)
Logical AND Data Memory to ACC
Data in the Accumulator and the specified Data Memory perform a bitwise logical AND
operation. The result is stored in the Accumulator.
ACC ← ACC ″AND″ [m]
Z
AND A,x
Description
Operation
Affected flag(s)
Logical AND immediate data to ACC
Data in the Accumulator and the specified immediate data perform a bit wise logical AND
operation. The result is stored in the Accumulator.
ACC ← ACC ″AND″ x
Z
ANDM A,[m]
Description
Operation
Affected flag(s)
Logical AND ACC to Data Memory
Data in the specified Data Memory and the Accumulator perform a bitwise logical AND
operation. The result is stored in the Data Memory.
[m] ← ACC ″AND″ [m]
Z
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CALL addr
Description
Operation
Affected flag(s)
Subroutine call
Unconditionally calls a subroutine at the specified address. The Program Counter then
increments by 1 to obtain the address of the next instruction which is then pushed onto the
stack. The specified address is then loaded and the program continues execution from this
new address. As this instruction requires an additional operation, it is a two cycle instruction.
Stack ← Program Counter + 1
Program Counter ← addr
None
CLR [m]
Description
Operation
Affected flag(s)
Clear Data Memory
Each bit of the specified Data Memory is cleared to 0.
[m] ← 00H
None
CLR [m].i
Description
Operation
Affected flag(s)
Clear bit of Data Memory
Bit i of the specified Data Memory is cleared to 0.
[m].i ← 0
None
CLR WDT
Description
Operation
Affected flag(s)
Clear Watchdog Timer
The TO, PDF flags and the WDT are all cleared.
WDT cleared
TO ← 0
PDF ← 0
TO, PDF
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
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
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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
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
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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
Return from subroutine
RET
Description
The Program Counter is restored from the stack. Program execution continues at the restored
address.
Operation
Program Counter ← Stack
Affected flag(s)
None
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
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Rotate Data Memory left with result in ACC
RLA [m]
Description
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.
Operation
ACC.(i+1) ← [m].i; (i=0~6)
ACC.0 ← [m].7
Affected flag(s)
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
Rotate Data Memory right with result in ACC
RRA [m]
Description
Data in the specified Data Memory is rotated right by 1 bit with bit 0 rotated into bit 7.
The rotated result is stored in the Accumulator and the contents of the Data Memory remain
unchanged.
Operation
ACC.i ← [m].(i+1); (i=0~6)
ACC.7 ← [m].0
Affected flag(s)
None
RRC [m]
Description
Operation
Affected flag(s)
Rev. 1.20
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
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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
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
Rev. 1.20
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A/D Flash MCU with EEPROM
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
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
Rev. 1.20
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A/D Flash MCU with EEPROM
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
Read table (specific page or current page) to TBLH and Data Memory
TABRD [m]
Description
The low byte of the program code addressed by the table pointer (TBHP and TBLP or only
TBLP if no TBHP) is moved to the specified Data Memory and the high byte moved to
TBLH.
Operation
[m] ← program code (low byte)
TBLH ← program code (high byte)
Affected flag(s)
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
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A/D Flash MCU with EEPROM
XORM A,[m]
Description
Operation
Affected flag(s)
Logical XOR ACC to Data Memory
Data in the specified Data Memory and the Accumulator perform a bitwise logical XOR
operation. The result is stored in the Data Memory.
[m] ← ACC ″XOR″ [m]
Z
XOR A,x
Description
Operation
Affected flag(s)
Logical XOR immediate data to ACC
Data in the Accumulator and the specified immediate data perform a bitwise logical XOR
operation. The result is stored in the Accumulator.
ACC ← ACC ″XOR″ x
Z
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A/D Flash MCU with EEPROM
Package Information
Note that the package information provided here is for consultation purposes only. As this
information may be updated at regular intervals users are reminded to consult the Holtek website for
the latest version of the Package/Carton Information.
Additional supplementary information with regard to packaging is listed below. Click on the relevant
section to be transferred to the relevant website page.
• Package Information (include Outline Dimensions, Product Tape and Reel Specifications)
• The Operation Instruction of Packing Materials
• Carton information
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24-pin SSOP (150mil) Outline Dimensions
Symbol
Dimensions in inch
Min.
Nom.
Max.
A
—
0.236 BSC
—
B
—
0.154 BSC
—
C
0.008
—
0.012
C’
—
0.341 BSC
—
D
—
—
0.069
E
—
0.025 BSC
—
F
0.004
—
0.010
G
0.016
—
0.050
H
0.004
—
0.010
α
0°
—
8°
Symbol
Rev. 1.20
Dimensions in mm
Min.
Nom.
Max.
—
A
—
6.000 BSC
B
—
3.900 BSC
—
C
0.20
—
0.30
C’
—
8.660 BSC
—
D
—
—
1.75
E
—
0.635 BSC
—
F
0.10
—
0.25
G
0.41
—
1.27
H
0.10
—
0.25
α
0°
—
8°
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HT66F0195
A/D Flash MCU with EEPROM
28-pin SSOP (150mil) Outline Dimensions
Symbol
Dimensions in inch
Min.
Nom.
Max.
A
—
0.236 BSC
—
B
—
0.154 BSC
—
C
0.008
—
0.012
C’
—
0.390 BSC
—
D
—
—
0.069
E
—
0.025 BSC
—
F
0.004
—
0.010
G
0.016
—
0.050
H
0.004
—
0.010
α
0°
—
8°
Symbol
Rev. 1.20
Dimensions in mm
Min.
Nom.
Max.
A
—
6.0 BSC
—
B
—
3.9 BSC
—
C
0.20
—
0.30
C’
—
9.9 BSC
—
D
—
—
1.75
E
—
0.635 BSC
—
F
0.10
—
0.25
G
0.41
—
1.27
H
0.10
—
0.25
α
0°
—
8°
184
September 10, 2020
HT66F0195
A/D Flash MCU with EEPROM
Copyright© 2020 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.
Rev. 1.20
185
September 10, 2020