Data Sheet

Touch Key Flash Type 8-Bit MCU with LCD/LED Driver
BS85B12-3/BS85C20-3/BS85C20-5
Revision: V1.40
Date: ��
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Table of Contents
Features............................................................................................................. 7
CPU Features.......................................................................................................................... 7
Peripheral Features.................................................................................................................. 7
Selection Table.................................................................................................. 8
Block Diagram................................................................................................... 9
Pin Assignment................................................................................................. 9
Pin Description................................................................................................11
BS85B12-3..............................................................................................................................11
BS85C20-3............................................................................................................................. 13
BS85C20-5............................................................................................................................. 17
Absolute Maximum Ratings........................................................................... 20
D.C. Characteristics........................................................................................ 21
A.C. Characteristics........................................................................................ 22
Power-on Reset Characteristics.................................................................... 23
Oscillator Temperature/Frequency Characteristics.................................... 24
System Architecture....................................................................................... 26
Clocking and Pipelining.......................................................................................................... 26
Program Counter.................................................................................................................... 27
Stack...................................................................................................................................... 28
Arithmetic and Logic Unit – ALU............................................................................................ 28
Flash Program Memory.................................................................................. 29
Structure................................................................................................................................. 29
Special Vectors...................................................................................................................... 29
Look-up Table......................................................................................................................... 29
Table Program Example......................................................................................................... 30
In Circuit Programming.......................................................................................................... 31
RAM Data Memory.......................................................................................... 32
Structure................................................................................................................................. 32
Special Function Register Description......................................................... 32
Indirect Addressing Registers – IAR0, IAR1.......................................................................... 32
Memory Pointers – MP0, MP1............................................................................................... 33
Bank Pointer – BP.................................................................................................................. 35
Accumulator – ACC................................................................................................................ 36
Program Counter Low Register – PCL................................................................................... 36
Look-up Table Registers – TBLP, TBHP, TBLH...................................................................... 36
Status Register – STATUS..................................................................................................... 36
Rev. 1.40
2
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
EEPROM Data Memory................................................................................... 38
EEPROM Data Memory Structure......................................................................................... 38
Reading Data from the EEPROM.......................................................................................... 40
Writing Data to the EEPROM................................................................................................. 40
Write Protection...................................................................................................................... 40
EEPROM Interrupt................................................................................................................. 41
Programming Considerations................................................................................................. 41
Programming Examples......................................................................................................... 41
Oscillator......................................................................................................... 42
Oscillator Overview................................................................................................................ 42
System Clock Configurations................................................................................................. 42
Internal High Speed RC Oscillator – HIRC............................................................................ 42
External 32.768kHz Crystal Oscillator – LXT (BS85C20-5 only)........................................... 43
LXT Oscillator Low Power Function (BS85C20-5 only)......................................................... 44
Internal Low Speed RC Oscillator – LIRC.............................................................................. 44
Operating Modes and System Clocks.......................................................... 44
System Clocks....................................................................................................................... 44
Control Register..................................................................................................................... 46
System Operation Modes....................................................................................................... 47
Operating Mode Switching..................................................................................................... 48
NORMAL Mode to SLOW Mode Switching............................................................................ 49
SLOW Mode to NORMAL Mode Switching............................................................................ 49
Entering the SLEEP Mode..................................................................................................... 49
Entering the IDLE0 Mode....................................................................................................... 50
Entering the IDLE1 Mode....................................................................................................... 50
Standby Current Considerations............................................................................................ 50
Wake-up................................................................................................................................. 51
Programming Considerations................................................................................................. 51
Watchdog Timer.............................................................................................. 52
Watchdog Timer Clock Source............................................................................................... 52
Watchdog Timer Control Register.......................................................................................... 52
Watchdog Timer Operation.................................................................................................... 53
Reset and Initialisation................................................................................... 54
Reset Functions..................................................................................................................... 54
Reset Initial Conditions.......................................................................................................... 55
Input/Output Ports.......................................................................................... 59
I/O Register List..................................................................................................................... 59
Pull-high Resistors................................................................................................................. 60
Port A Wake-up...................................................................................................................... 60
I/O Port Control Register........................................................................................................ 61
Pin Re-mapping Functions..................................................................................................... 61
I/O Pin Structures................................................................................................................... 66
Programming Considerations................................................................................................. 66
Rev. 1.40
3
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Timer Modules – TM....................................................................................... 67
Introduction............................................................................................................................ 67
TM Operation......................................................................................................................... 67
TM Clock Source.................................................................................................................... 68
TM Interrupts.......................................................................................................................... 68
TM External Pins.................................................................................................................... 68
TM Input/Output Pin Control Registers.................................................................................. 69
Programming Considerations................................................................................................. 72
Compact Type TM – CTM............................................................................... 73
Compact TM Operation.......................................................................................................... 73
Compact Type TM Register Description................................................................................ 74
Compact Type TM Operating Modes..................................................................................... 77
Compare Match Output Mode................................................................................................ 77
Timer/Counter Mode.............................................................................................................. 79
PWM Output Mode................................................................................................................. 80
Standard Type TM – STM............................................................................... 82
Standard TM Operation.......................................................................................................... 82
Standard Type TM Register Description................................................................................ 83
Standard Type TM Operating Modes..................................................................................... 87
Compare Match Output Mode................................................................................................ 87
Timer/Counter Mode.............................................................................................................. 88
PWM Output Mode................................................................................................................. 89
Single Pulse Mode................................................................................................................. 91
Capture Input Mode............................................................................................................... 93
Enhanced Type TM – ETM.............................................................................. 94
Enhanced TM Operation........................................................................................................ 94
Enhanced Type TM Register Description............................................................................... 95
Enhanced Type TM Operating Modes................................................................................. 100
Compare Output Mode......................................................................................................... 101
Timer/Counter Mode............................................................................................................ 105
PWM Output Mode............................................................................................................... 105
Single Pulse Output Mode....................................................................................................111
Capture Input Mode..............................................................................................................113
Touch Key Function......................................................................................115
Touch Key Structure..............................................................................................................115
Touch Key Register Definition...............................................................................................115
Touch Key Operation.............................................................................................................119
Touch Key Interrupt.............................................................................................................. 120
Programming Considerations............................................................................................... 120
Rev. 1.40
4
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Serial Interface Module – SIM...................................................................... 121
SPI Interface........................................................................................................................ 121
SPI Registers....................................................................................................................... 122
SPI Communication............................................................................................................. 125
I2C Interface......................................................................................................................... 127
I2C Registers........................................................................................................................ 128
I2C Bus Communication....................................................................................................... 132
I2C Bus Start Signal.............................................................................................................. 132
Slave Address...................................................................................................................... 133
I2C Bus Read/Write Signal................................................................................................... 133
I2C Bus Slave Address Acknowledge Signal........................................................................ 134
I2C Bus Data and Acknowledge Signal................................................................................ 134
I2C Time-out Control............................................................................................................. 135
Peripheral Clock Output............................................................................... 136
Peripheral Clock Operation.................................................................................................. 136
Interrupts....................................................................................................... 137
Interrupt Registers................................................................................................................ 137
Interrupt Register Contents.................................................................................................. 138
Interrupt Operation............................................................................................................... 144
External Interrupt.................................................................................................................. 146
Multi-function Interrupt......................................................................................................... 146
Time Base Interrupts............................................................................................................ 146
External Peripheral Interrupt................................................................................................ 148
LVD Interrupt........................................................................................................................ 149
TM Interrupts........................................................................................................................ 149
EEPROM Interrupt............................................................................................................... 149
Touch Key Interrupts............................................................................................................ 149
SIM Interrupt........................................................................................................................ 150
Interrupt Wake-up Function.................................................................................................. 150
Programming Considerations............................................................................................... 150
Low Voltage Detector – LVD........................................................................ 151
LVD Register........................................................................................................................ 151
LVD Operation...................................................................................................................... 152
LCD Driver – SCOM and SSEG Function.................................................... 152
LCD Operation..................................................................................................................... 152
LCD Bias Control................................................................................................................. 154
LCD Driver Registers........................................................................................................... 154
LED Driver..................................................................................................... 156
LED Driver Operation........................................................................................................... 156
LED Driver Registers........................................................................................................... 156
Application Circuits...................................................................................... 157
Rev. 1.40
5
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Instruction Set............................................................................................... 158
Introduction.......................................................................................................................... 158
Instruction Timing................................................................................................................. 158
Moving and Transferring Data.............................................................................................. 158
Arithmetic Operations........................................................................................................... 158
Logical and Rotate Operation.............................................................................................. 159
Branches and Control Transfer............................................................................................ 159
Bit Operations...................................................................................................................... 159
Table Read Operations........................................................................................................ 159
Other Operations.................................................................................................................. 159
Instruction Set Summary............................................................................. 160
Table Conventions................................................................................................................ 160
Instruction Definition.................................................................................... 162
Package Information.................................................................................... 171
24-pin SKDIP (300mil) Outline Dimensions......................................................................... 172
24-pin SOP (300mil) Outline Dimensions............................................................................ 174
24-pin SSOP (150mil) Outline Dimensions.......................................................................... 175
28-pin SKDIP (300mil) Outline Dimensions......................................................................... 176
28-pin SOP (300mil) Outline Dimensions............................................................................ 177
28-pin SSOP (150mil) Outline Dimensions.......................................................................... 178
44-pin LQFP (10mm×10mm) (FP2.0mm) Outline Dimensions............................................ 179
Rev. 1.40
6
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Features
CPU Features
• Operating Voltage:
fSYS= 8MHz: VLVR~5.5V
fSYS= 12MHz: 2.7V~5.5V
fSYS= 16MHz: 4.5V~5.5V
• Power down and wake-up functions to reduce power consumption
• Oscillator types:
External 32.768kHz Crystal – LXT
Internal RC – HIRC
Internal 32kHz RC – LIRC
• Multi-mode operation: NORMAL, SLOW, IDLE and SLEEP
• All instructions executed in one or two instruction cycles
• Table read instructions
• 63 powerful instructions
• Up to 8 subroutine nesting levels
• Bit manipulation instruction
Peripheral Features
• Fully integrated 12 or 20 touch key functions -- require no external components
• Flash Program Memory: 2K×15 or 4K×15
• RAM Data Memory: 256×8 or 384×8
• EEPROM Memory: 64×8 or 128×8
• Watchdog Timer function
• Up to 38 bidirectional I/O lines
• Two or three Timer Modules
• Dual Time-Base functions for generation of fixed time interrupt signals
• I2C and SPI interfaces
• Low voltage reset function
• Software controlled 4×14 or 4×22 LCD driver with 1/3 bias
• Software controlled 6×8 or 8×14 LED driver
Rev. 1.40
7
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
General Description
These devices are a series of Flash Memory type 8-bit high performance RISC architecture
microcontrollers with fully integrated touch key functions and LCD/LED drivers. With all touch
key functions provided internally and with the convenience of Flash Memory multi-programming
features, this device range has all the features to offer designers a reliable and easy means of
implementing Touch Keys within their products applications. The touch key functions are fully
integrated completely eliminating the need for external components. The inclusion of both LCD
and LED driver functions allows for easy and cost effective solutions in applications that require to
interface to these display types.
In addition to the flash program memory, other memory includes an area of RAM Data Memory
as well as an area of EEPROM memory for storage of non-volatile data such as serial numbers, calibration data etc. Protective features such as an internal Watchdog Timer, Low Voltage
Reset and Low Voltage Detector functions coupled with excellent noise immunity and ESD
protection ensure that reliable operation is maintained in hostile electrical environments.
A choice of oscillator functions are provided including a fully integrated system oscillator which requires no external components for its implementation. The ability to operate and switch
dynamically between a range of operating modes using different clock sources gives users the ability
to optimise microcontroller operation and minimise power consumption. Easy communication
with the outside world is provided using the internal I2C and SPI interfaces, while the inclusion of
flexible I/O programming features, Timer Modules and many other features further enhance device
functionality and flexibility.
These touch key devices will find excellent use in a huge range of modern Touch Key product
applications such as instrumentation, household appliances, electronically controlled tools to name
but a few.
Selection Table
Part No.
Internal
Clock
VDD
BS85B12-3
8MHz
12MHz
16MHz
VLVR ~ 8MHz ~
5.5V 16MHz
2K×15
256×8
64×8
22
HIRC
LIRC
2
12
4×14
6×8
1
4
24/28SKDIP
24/28SOP
24/28SSOP
BS85C20-3
8MHz
12MHz
16MHz
VLVR ~ 8MHz ~
5.5V 16MHz
4K×15
384×8
128×8
38
HIRC
LIRC
3
20
4×22
8×14
1
8
28SKDIP
28SOP
28SSOP
44LQFP
BS85C20-5
8MHz
12MHz
16MHz
VLVR ~ 8MHz ~
5.5V 16MHz
4K×15
384×8
128×8
38
HIRC
LIRC
LXT
3
20
4×22
8×14
1
8
28SKDIP
28SOP
28SSOP
44LQFP
Rev. 1.40
System Program
Data
Data
Oscillator Timer Touch LCD
LED SPI/
Stack
I/O
Clock Memory Memory EEPROM
Type
Module Key Driver Driver I2C
8
Package
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Block Diagram

Pin Assignment
P C 0 /[T P 0 _ 0 ]/[S D O ]/S S E G 0 /K E Y 1
1
P C 1 /[T P 0 _ 1 ]/[S C K /S C L ]/S S E G 1 /K E Y 2
2
P C 2 /[T P 1 B _ 0 ]/[S D I/S D A ]/S S E G 2 /K E Y 3
3
2 4
2 3
2 2
P C 3 /[T P 1 B _ 1 ]/[S C S ]/S S E G 3 /K E Y 4
4
P C 4 /[T C K 0 ]/[IN T 0 ]/[T P 1 B _ 2 ]/S S E G 4 /K E Y 5
5
P C 5 /[T C K 1 ]/[IN T 1 ]/[T P 1 A ]/S S E G 5 /K E Y 6
6
P C 6 /[P C K ]/S S E G 6 /K E Y 7
7
P C 7 /P IN T /S S E G 7 /K E Y 8
8
K E Y 1 1
9
K E Y 1 2
1 0
V S S
1 1
V D D
1 2
2 1
2 0
1 9
1 8
1 7
1 6
1 5
1 4
1 3
P B 0 /T P 0 _ 0 /S C O M 0
P B 1 /T P 0 _ 1 /S C O M 1
P B 2 /T P 1 B _ 0 /S C O M 2
P B 3 /T P 1 B _ 1 /S C O M 3
P A 1 /T C K 1 /IN T 1 /S S E G 1 0
P A 4 /T C K 0 /IN T 0 /S S E G 1 1
P A 5 /S S E G 1 2
P A 6 /S S E G 1 3
P A 3 /S C S
P A 0 /S D I/S D A
P A 2 /S C K /S C L
P A 7 /S D O
P C 0 /[T P 0 _ 0 ]/[S D O ]/S S E G 0 /K E Y 1
1
2 8
P B 0 /T P 0 _ 0 /S C O M 0
P C 1 /[T P 0 _ 1 ]/[S C K ]/[S C L ]/S S E G 1 /K E Y 2
2
2 7
P B 1 /T P 0 _ 1 /S C O M 1
P C 2 /[T P 1 B _ 0 ]/[S D I]/[S D A ]/S S E G 2 /K E Y 3
3
2 6
P B 2 /T P 1 B _ 0 /S C O M 2
P C 3 /[T P 1 B _ 1 ]/[S C S ]/S S E G 3 /K E Y 4
4
2 5
P B 3 /T P 1 B _ 1 /S C O M 3
P C 4 /[T C K 0 ]/[IN T 0 ]/[T P 1 B _ 2 ]/S S E G 4 /K E Y 5
5
2 4
P B 4 /T P 1 B _ 2 /P C K /S S E G 8
P C 5 /[T C K 1 ]/[IN T 1 ]/[T P 1 A ]/S S E G 5 /K E Y 6
6
2 3
P B 5 /P IN T /T P 1 A /S S E G 9
P C 6 /[P C K ]/S S E G 6 /K E Y 7
7
2 2
P A 1 /T C K 1 /IN T 1 /S S E G 1 0
P C 7 /[P IN T ]/S S E G 7 /K E Y 8
8
2 1
P A 4 /T C K 0 /IN T 0 /S S E G 1 1
K E Y 9
9
2 0
P A 5 /S S E G 1 2
K E Y 1 0
1 0
1 9
P A 6 /S S E G 1 3
K E Y 1 1
1 1
1 8
P A 3 /S C S
K E Y 1 2
1 2
1 7
P A 0 /S D I/S D A
V S S
1 3
1 6
P A 2 /S C K /S C L
V D D
1 4
1 5
P A 7 /S D O
Rev. 1.40
9
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
P B 1 /T P 0 _ 1 /T P 2 _ 0 /S C O M 1
P C 2 /[T P 1 B _ 0 ]/[S D I]/[S D A ]/S S E G 2 /K E Y 3
3
2 6
P B 2 /T P 1 B _ 0 /T P 2 _ 1 /S C O M 2
P C 3 /[T P 1 B _ 1 ]/[S C S ]/S S E G 3 /K E Y 4
4
2 5
P B 3 /T P 1 B _ 1 /S C O M 3
P C 4 /[T C K 0 ]/[IN T 0 ]/[T P 1 B _ 2 ]/S S E G 4 /K E Y 5
5
2 4
P B 4 /T P 1 B _ 2 /P C K /S S E G 8
P C 5 /[T C K 1 ]/[IN T 1 ]/[T P 1 A ]/S S E G 5 /K E Y 6
6
2 3
P B 5 /P IN T /T P 1 A /S S E G 9
P C 6 /T C K 2 /[P C K ]/S S E G 6 /K E Y 7
7
2 2
P A 1 /T C K 1 /IN T 1 /S S E G 1 0
P C 7 /[P IN T ]/S S E G 7 /K E Y 8
8
2 1
P A 4 /T C K 0 /IN T 0 /S S E G 1 1
K E Y 9
9
2 0
P A 5 /S S E G 1 2
K E Y 1 0
1 0
1 9
P A 6 /S S E G 1 3
K E Y 1 1
1 1
1 8
P A 3 /S C S
K E Y 1 2
1 2
1 7
P A 0 /S D I/S D A
V S S
1 3
1 6
P A 2 /S C K /S C L
V D D
1 4
1 5
P A 7 /S D O
P
P E 2
P E 1
P B 2
P B 0 /T P 0 _ 0 /S C O M 0
2 7
P B
2 8
2
C 0 /[T P 0
P 0 _ 1 ]/[S
1 B _ 0 ]/[S
3 /[T P 1 B
1
P
P C 1 /[T
P C 2 /[T P
P C
P C 0 /[T P 0 _ 0 ]/[S D O ]/S S E G 0 /K E Y 1
P C 1 /[T P 0 _ 1 ]/[S C K ]/[S C L ]/S S E G 1 /K E Y 2
/T P 1 B _ 0 /T P 2
1 /T P 0 _ 1 /T P 2
P B 0 /T P 0
E 3 /[S C K ]/[S C
/[T P 2 _ 1 ]/[S C
/[T P 2 _ 0 ]/[P C
P E 0 /[P IN
_ 0 ]/[S D O ]/S S
C K ]/[S C L ]/S S
D I]/[S D A ]/S S
_ 1 ]/[S C S ]/S S
_ 1 /S
_ 0 /S
_ 0 /S
L ]/S S
S ]/S S
K ]/S S
T ]/S S
E G 0
E G 1
E G 2
E G 3
C O M 2
C O M 1
C O M 0
G 1 7
G 1 6
G 1 5
G 1 4
1
E
E
E
E
/K
/K
/K
/K
E Y
E Y
E Y
E Y
3
4
2
P C 4 /[T C K 0 ]/[IN T 0 ]/[T P 1 B _
P C 5 /[T C K 1 ]/[IN T 1 ]/[T P 1
P C 6 /T C K 2 /[P C
P C 7 /[P IN
P D
2 ]/S
A ]/S
K ]/S
T ]/S
0 /[T
S E
S E
S E
S E
C K
P D
P D
P D
P D
P D
P D
G 4 /K
G 5 /K
G 6 /K
G 7 /K
2 ]/K E
1 /K E
2 /K E
3 /K E
4 /K E
5 /K E
6 /K E
E Y 5
E Y 6
E Y 7
E Y 8
Y 1 3
Y 1 4
Y 1 5
Y 1 6
Y 1 7
Y 1 8
Y 1 9
4 4 4 3 4 2 4 1 4 0 3 9 3 8 3 7 3 6 3 5 3 4
1
2
3 3
3 2
3
3 1
4
3 0
5
2 9
6
7
2 8
2 7
8
2 6
9
1 0
1 1
2 5
2 4
1 2 1 3 1 4 1 5 1 6 1 7 1 8 1 9 2 0 2 1 2 2
2 3
P B 3
P B 4
P B 5
P B 6
P B 7
P E 4
P E 5
P A 1
P A 4
P A 5
P A 6
/T P
/T P
/P IN
/S S
/S S
/[S D
/[S D
/T C
/T C
/S S
/S S
1 B _ 1 /S C O
1 B _ 2 /P C K
T /T P 1 A /S
E G 2 0
E G 2 1
I]/[S D A ]/S
O ]/S S E G
K 1 /IN T 1 /S
K 0 /IN T 0 /S
E G 1 2
E G 1 3
M 3
/S S E G 8
S E G 9
S E G 1 8
1 9
S E G 1 0
S E G 1 1
P A 3
P A 0
P A 2
P A 7
V D D
V S S
K E Y
K E Y
K E Y
K E Y
P D 7
5
2 4
P B 4 /T P 1 B _ 2 /P C K /S S E G 8
P C 5 /[T C K 1 ]/[IN T 1 ]/[T P 1 A ]/S S E G 5 /K E Y 6
6
2 3
P B 5 /P IN T /T P 1 A /S S E G 9
P C 6 /T C K 2 /[P C K ]/S S E G 6 /K E Y 7
7
2 2
P A 1 /T C K 1 /IN T 1 /S S E G 1 0
P C 7 /[P IN T ]/S S E G 7 /K E Y 8
8
2 1
P A 4 /T C K 0 /IN T 0 /S S E G 1 1
K E Y 9
9
2 0
O S C 2
K E Y 1 0
1 0
1 9
O S C 1
K E Y 1 1
1 1
1 8
P A 3 /S C S
K E Y 1 2
1 2
1 7
P A 0 /S D I/S D A
V S S
1 3
1 6
P A 2 /S C K /S C L
V D D
1 4
1 5
P A 7 /S D O
P B 2
P B
P C 4 /[T C K 0 ]/[IN T 0 ]/[T P 1 B _ 2 ]/S S E G 4 /K E Y 5
C S
D I/S D A
C K /S C L
D O
P B 3 /T P 1 B _ 1 /S C O M 3
/S
/S
/S
/S
2 5
P
P E 2
P E 1
4
2
P B 2 /T P 1 B _ 0 /T P 2 _ 1 /S C O M 2
P C 3 /[T P 1 B _ 1 ]/[S C S ]/S S E G 3 /K E Y 4
1
2 6
/T P 1 B _ 0 /T P 2
1 /T P 0 _ 1 /T P 2
P B 0 /T P 0
E 3 /[S C K ]/[S C
/[T P 2 _ 1 ]/[S C
/[T P 2 _ 0 ]/[P C
P E 0 /[P IN
_ 0 ]/[S D O ]/S S
C K ]/[S C L ]/S S
D I]/[S D A ]/S S
_ 1 ]/[S C S ]/S S
3
C 0 /[T P 0
P 0 _ 1 ]/[S
1 B _ 0 ]/[S
3 /[T P 1 B
P B 1 /T P 0 _ 1 /T P 2 _ 0 /S C O M 1
P C 2 /[T P 1 B _ 0 ]/[S D I]/[S D A ]/S S E G 2 /K E Y 3
P
P C 1 /[T
P C 2 /[T P
P C
P B 0 /T P 0 _ 0 /S C O M 0
2 7
E Y 2 0
2 8
2
0
1
1
1
1
9
/K
P C 0 /[T P 0 _ 0 ]/[S D O ]/S S E G 0 /K E Y 1
P C 1 /[T P 0 _ 1 ]/[S C K ]/[S C L ]/S S E G 1 /K E Y 2
_ 1 /S
_ 0 /S
_ 0 /S
L ]/S S
S ]/S S
K ]/S S
T ]/S S
E G 0
E G 1
E G 2
E G 3
E
E
E
E
/K
/K
/K
/K
C O M 2
C O M 1
C O M 0
G 1 7
G 1 6
G 1 5
G 1 4
E Y 1
E Y 2
E Y 3
E Y 4
P C 4 /[T C K 0 ]/[IN T 0 ]/[T P 1 B _
P C 5 /[T C K 1 ]/[IN T 1 ]/[T P 1
P C 6 /T C K 2 /[P C
P C 7 /[P IN
P D
2 ]/S
A ]/S
K ]/S
T ]/S
0 /[T
S E
S E
S E
S E
C K
P D
P D
P D
P D
P D
P D
G 4 /K
G 5 /K
G 6 /K
G 7 /K
2 ]/K E
1 /K E
2 /K E
3 /K E
4 /K E
5 /K E
6 /K E
E Y
E Y
E Y
E Y
Y 1
Y 1
Y 1
Y 1
Y 1
Y 1
Y 1
4 4 4 3 4 2 4 1 4 0 3 9 3 8 3 7 3 6 3 5 3 4
5
6
1
5
6
3
3 1
4
3 0
5
3
6
7
7
8
8
9
3 3
3 2
7
8
4
2
2 8
2 7
2 6
9
1 0
1 1
2 9
2 5
2 4
1 2 1 3 1 4 1 5 1 6 1 7 1 8 1 9 2 0 2 1 2 2
2 3
P B 3
P B 4
P B 5
P B 6
P B 7
P E 4
P E 5
P A 1
P A 4
O S C
O S C
/T P
/T P
/P IN
/S S
/S S
/[S D
/[S D
/T C
/T C
2
1
1 B _ 1 /S C O
1 B _ 2 /P C K
T /T P 1 A /S
E G 2 0
E G 2 1
I]/[S D A ]/S
O ]/S S E G
K 1 /IN T 1 /S
K 0 /IN T 0 /S
M 3
/S S E G 8
S E G 9
S E G 1 8
1 9
S E G 1 0
S E G 1 1
P A 3
P A 0
P A 2
P A 7
V D D
V S S
K E Y
K E Y
K E Y
K E Y
P D 7
/S
/S
/S
/S
1
1
1
9
/K
2
1
0
C S
D I/S D A
C K /S C L
D O
E Y 2 0
Note: 1. Bracketed pin names indicate non-default pinout remapping locations.
2. If the pin-shared pin functions have multiple outputs simultaneously, its pin names at the right side of the
" / " sign can be used for higher priority.
Rev. 1.40
10
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
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.
BS85B12-3
Pin Name
PA0/SDI/SDA
Register
Select
I/T
PA0
PAWU
PAPU
ST
Function
SIMC0
ST
SIMC0
ST
NMOS I2C data I/O
PA1
PAWU
PAPU
ST
CMOS General purpose I/O. Register enabled pull-up and wake-up.
ST
—
Timer Module 1 input
ST
—
External interrupt 1 input
SLCDCn
—
LCD
PA2
PAWU
PAPU
ST
CMOS General purpose I/O. Register enabled pull-up and wake-up.
SCK
SIMC0
ST
CMOS SPI serial clock
SCL
SIMC0
ST
NMOS I2C clock
PA3
PAWU
PAPU
ST
CMOS General purpose I/O. Register enabled pull-up and wake-up.
SCS
SIMC0
ST
CMOS SPI slave select
PA4
PAWU
PAPU
ST
CMOS General purpose I/O. Register enabled pull-up and wake-up.
ST
—
Timer Module 0 input
INTC0
ST
—
External interrupt 0 input
SLCDCn
—
LCD
PAWU
PAPU
ST
SLCDCn
—
PAWU
PAPU
ST
SLCDCn
—
PA7
PAWU
PAPU
ST
CMOS General purpose I/O. Register enabled pull-up and wake-up.
SDO
SIMC0
—
CMOS SPI data output
PA5
PA6
SSEG13
PB0/TP0_0/
SCOM0
PB1/TP0_1/
SCOM1
PB2/TP1B_0/
SCOM2
PB3/TP1B_1/
SCOM3
Rev. 1.40
Software controlled LCD SEG
TM0C0
SSEG12
PA7/SDO
SPI data input
INTC0
SSEG11
PA6/SSEG13
—
TM1C0
PA4/TCK0/
TCK0
INT0/SSEG11
INT0
PA5/SSEG12
CMOS General purpose I/O. Register enabled pull-up and wake-up.
SDI
SSEG10
PA3/SCS
Description
SDA
PA1/TCK1/
TCK1
INT1/SSEG10
INT1
PA2/SCK/SCL
O/T
PB0
Software controlled LCD SEG
CMOS General purpose I/O. Register enabled pull-up and wake-up.
LCD
Software controlled LCD SEG
CMOS General purpose I/O. Register enabled pull-up and wake-up.
LCD
Software controlled LCD SEG
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up.
TP0_0
TMPCn
ST
CMOS TM0 I/O
SCOM0
SLCDCn
—
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up.
TP0_1
TMPCn
ST
CMOS TM0 I/O
SCOM1
SLCDCn
—
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up.
TP1B_0
TMPCn
ST
CMOS TM1 I/O
SCOM2
SLCDCn
—
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up.
TP1B_1
TMPCn
ST
CMOS TM1 I/O
SCOM3
SLCDCn
—
PB1
PB2
PB3
LCD
LCD
LCD
LCD
Software controlled LCD COM
Software controlled LCD COM
Software controlled LCD COM
Software controlled LCD COM
11
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Pin Name
Function
Description
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up.
ST
CMOS TM1 I/O
PCK
SIMC0
—
CMOS Peripheral clock output
PB5
PINT
PB5/PINT/
TP1A/SSEG9 TP1A
SSEG9
SLCDCn
—
PBPU
ST
MFI3
ST
TMPCn
ST
LCD
Software controlled LCD SEG
CMOS General purpose I/O. Register enabled pull-up.
—
Peripheral interrupt input
CMOS TM1 I/O
SLCDCn
—
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
TP0_0
TMPCn
ST
CMOS TM0 I/O
SDO
SIMC0
—
CMOS SPI data output
PC0
LCD
Software controlled LCD SEG
Software controlled LCD SEG
SSEG0
SLCDCn
—
LCD
KEY1
TKMnC1
NS
—
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
TMPCn
ST
CMOS TM0 I/O
SIMC0
ST
CMOS SPI clock
SIMC0
ST
NMOS I2C clock
SLCDCn
—
TKMnC1
NS
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
TMPCn
ST
CMOS TM1 I/O
SIMC0
ST
SIMC0
ST
PC1
TP0_1
PC1/TP0_1/
SCK
SCK/SCL/
SSEG1/KEY2 SCL
SSEG1
KEY2
PC2
TP1B_0
PC2/TP1B_0/ SDI
SDI/SDA/
SSEG2/KEY3 SDA
SSEG2
KEY3
PC3
PC3/TP1B_1/ TP1B_1
SCS/SSEG3/ SCS
KEY4
SSEG3
KEY4
PC4
TCK0
PC4/TCK0/
INT0
INT0/TP1B_2/
SSEG4/KEY5 TP1B_2
SSEG4
KEY5
PC5
TCK1
PC5/TCK1/
INT1
INT1/TP1A/
SSEG5/KEY6 TP1A
SSEG5
KEY6
PC6
PCK
PC6/PCK/
SSEG6/KEY7 SSEG6
KEY7
Rev. 1.40
O/T
TMPCn
SSEG8
PC0/TP0_0/
SDO/SSEG0/
KEY1
I/T
TP1B_2
PB4
PB4/TP1B_2/
PCK/SSEG8
Register
Select
LCD
—
—
Touch key input
Software controlled LCD SEG
Touch key input
SPI data input
NMOS I2C data I/O
SLCDCn
—
LCD
TKMnC1
NS
—
Software controlled LCD SEG
Touch key input
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
TMPCn
ST
CMOS TM1 I/O
SIMC0
ST
CMOS SPI slave select
SLCDCn
—
LCD
TKMnC1
NS
—
PCPU
ST
Software controlled LCD SEG
Touch key input
CMOS General purpose I/O. Register enabled pull-up.
TM0C0
ST
—
Timer Module 0 input
INTC0
ST
—
External interrupt 0 input
TMPCn
ST
SLCDCn
—
CMOS TM1 I/O
LCD
TKMnC1
NS
—
PCPU
ST
Software controlled LCD SEG
Touch key input
CMOS General purpose I/O. Register enabled pull-up.
TM1C0
ST
—
Timer Module 1 input
INTC0
ST
—
External interrupt 1 input
TMPCn
ST
CMOS TM1 I/O
SLCDCn
—
LCD
TKMnC1
NS
—
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
CMOS Peripheral clock output
SIMC0
—
SLCDCn
—
LCD
TKMnC1
NS
—
Software controlled LCD SEG
Touch key input
Software controlled LCD SEG
Touch key input
12
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Pin Name
Register
Select
I/T
PC7
PCPU
ST
PINT
MFI3
ST
—
SLCDCn
—
LCD
Function
PC7/PINT/
SSEG7/KEY8 SSEG7
O/T
Description
CMOS General purpose I/O. Register enabled pull-up.
Peripheral interrupt input
Software controlled LCD SEG
KEY8
TKMnC1
NS
—
Touch key input
KEY9
KEY9
—
NS
—
Touch key input
KEY10
KEY10
—
NS
—
Touch key input
KEY11
KEY11
—
NS
—
Touch key input
KEY12
KEY12
—
NS
—
Touch key input
VDD
VDD
—
PWR
—
Power supply
VSS
VSS
—
PWR
—
Ground
Note: I/T: Input type
O/T: Output type
Register Select: Indicates register which selects alternative function
PWR: Power
ST: Schmitt Trigger input
CMOS: CMOS output
NMOS: NMOS output
LCD: LCD COM or SEG Vbias output
NS: Non-standard input or output
The pins in the table reflect that of the package with the largest number of pins. For this reason not all pins
may exist on all package types.
BS85C20-3
Pin Name
PA0/SDI/SDA
Register
Select
I/T
PA0
PAWU
PAPU
ST
SDI
SIMC0
ST
SDA
SIMC0
ST
NMOS I2C data I/O
PA1
PAWU
PAPU
ST
CMOS General purpose I/O. Register enabled pull-up and wake-up.
TM1C0
ST
—
Timer Module 1 input
INTC0
ST
—
External interrupt 1 input
SLCDCn
—
LCD
PA2
PAWU
PAPU
ST
CMOS General purpose I/O. Register enabled pull-up and wake-up.
SCK
SIMC0
ST
CMOS SPI serial clock
SCL
SIMC0
ST
NMOS I2C clock
PA3
PAWU
PAPU
ST
CMOS General purpose I/O. Register enabled pull-up and wake-up.
SCS
SIMC0
ST
CMOS SPI slave select
PA4
PAWU
PAPU
ST
CMOS General purpose I/O. Register enabled pull-up and wake-up.
TM0C0
ST
—
Timer Module 0 input
INTC0
ST
—
External interrupt 0 input
SLCDCn
—
LCD
Function
PA1/TCK1/
TCK1
INT1/SSEG10
INT1
SSEG10
PA2/SCK/SCL
PA3/SCS
PA4/TCK0/
TCK0
INT0/SSEG11
INT0
SSEG11
Rev. 1.40
O/T
Description
CMOS General purpose I/O. Register enabled pull-up and wake-up.
—
SPI data input
Software controlled LCD SEG
Software controlled LCD SEG
13
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Pin Name
PA5/SSEG12
Register
Select
I/T
PAWU
PAPU
ST
SLCDCn
—
PAWU
PAPU
ST
SLCDCn
—
PA7
PAWU
PAPU
ST
CMOS General purpose I/O. Register enabled pull-up and wake-up.
SDO
SIMC0
—
CMOS SPI data output
PB0
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up.
TP0_0
TMPCn
ST
CMOS TM0 I/O
SCOM0
SLCDCn
—
Function
PA5
SSEG12
PA6/SSEG13
PA6
SSEG13
PA7/SDO
PB0/TP0_0/
SCOM0
PB1/TP0_1/
TP2_0/
SCOM1
PB1
O/T
Description
CMOS General purpose I/O. Register enabled pull-up and wake-up.
LCD
Software controlled LCD SEG
CMOS General purpose I/O. Register enabled pull-up and wake-up.
LCD
LCD
Software controlled LCD SEG
Software controlled LCD COM
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up.
TP0_1
TMPCn
ST
CMOS TM0 I/O
TP2_0
TMPCn
ST
CMOS TM2 I/O
SCOM1
SLCDCn
—
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up.
TMPCn
ST
CMOS TM1 I/O
TMPCn
ST
CMOS TM2 I/O
PB2
PB2/TP1B_0/ TP1B_0
TP2_1/
TP2_1
SCOM2
SCOM2
PB3
PB3/TP1B_1/
TP1B_1
SCOM3
SCOM3
LCD
LCD
Software controlled LCD COM
SLCDCn
—
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up.
Software controlled LCD COM
CMOS TM1 I/O
TMPCn
ST
SLCDCn
—
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up.
PB4/TP1B_2/ TP1B_2
PCK/SSEG8 PCK
TMPCn
ST
CMOS TM1 I/O
SIMC0
—
CMOS Peripheral clock output
SSEG8
SLCDCn
—
PB4
PB5
PINT
PB5/PINT/
TP1A/SSEG9 TP1A
SSEG9
PB6/SSEG20
PB7/SSEG21
PB6
SSEG20
PB7
SSEG21
PC0
TP0_0
PC0/TP0_0/
SDO/SSEG0/ SDO
KEY1
SSEG0
KEY1
PC1
TP0_1
PC1/TP0_1/
SCK
SCK/SCL/
SSEG1/KEY2 SCL
SSEG1
KEY2
Rev. 1.40
PBPU
ST
MFI3
ST
TMPCn
ST
SLCDCn
—
PBPU
ST
SLCDCn
—
PBPU
ST
LCD
LCD
Software controlled LCD COM
Software controlled LCD SEG
CMOS General purpose I/O. Register enabled pull-up.
—
Peripheral interrupt input
CMOS TM1 I/O
LCD
Software controlled LCD SEG
CMOS General purpose I/O. Register enabled pull-up.
LCD
Software controlled LCD SEG
CMOS General purpose I/O. Register enabled pull-up.
SLCDCn
—
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
LCD
TMPCn
ST
CMOS TM0 I/O
SIMC0
—
CMOS SPI data output
SLCDCn
—
LCD
TKMnC1
NS
—
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
TMPCn
ST
CMOS TM0 I/O
SIMC0
ST
CMOS SPI clock
SIMC0
ST
NMOS I2C clock
SLCDCn
—
LCD
TKMnC1
NS
—
Software controlled LCD SEG
Software controlled LCD SEG
Touch key input
Software controlled LCD SEG
Touch key input
14
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Pin Name
Function
PC2
TP1B_0
PC2/TP1B_0/ SDI
SDI/SDA/
SSEG2/KEY3 SDA
SSEG2
SIMC0
ST
—
SPI data input
NMOS I2C data I/O
CMOS General purpose I/O. Register enabled pull-up.
TMPCn
ST
CMOS TM1 I/O
SIMC0
ST
CMOS SPI slave select
SLCDCn
—
LCD
TKMnC1
NS
—
PC4
PCPU
ST
TCK0
TM0C0
ST
—
Timer Module 0 input
INTC0
ST
—
External interrupt 0 input
TMPCn
ST
—
LCD
NS
—
PCPU
ST
TM1C0
ST
—
Timer Module 1 input
INTC0
ST
—
External interrupt 1 input
TMPCn
ST
Touch key input
CMOS TM1 I/O
—
PC6
PCPU
ST
TCK2
TM2C0
ST
Software controlled LCD SEG
Touch key input
CMOS General purpose I/O. Register enabled pull-up.
—
SIMC0
—
SSEG6
SLCDCn
—
LCD
KEY7
TKMnC1
NS
—
PCPU
ST
PD0
Software controlled LCD SEG
CMOS General purpose I/O. Register enabled pull-up.
LCD
KEY8
Touch key input
TKMnC1
—
PINT
PC7/PINT/
SSEG7/KEY8 SSEG7
Software controlled LCD SEG
SLCDCn
NS
PC7
Touch key input
CMOS TM1 I/O
TKMnC1
PCK
Software controlled LCD SEG
CMOS General purpose I/O. Register enabled pull-up.
SLCDCn
KEY6
Rev. 1.40
ST
ST
TCK1
PC5/TCK1/
INT1
INT1/TP1A/
SSEG5/KEY6 TP1A
SSEG5
PD6/KEY19
CMOS TM1 I/O
SIMC0
PCPU
PC5
PD5/KEY18
CMOS General purpose I/O. Register enabled pull-up.
ST
—
KEY5
PD4/KEY17
ST
LCD
PC4/TCK0/
INT0
INT0/TP1B_2/
SSEG4/KEY5 TP1B_2
SSEG4
PD3/KEY16
PCPU
TMPCn
—
KEY4
PD2/KEY15
Description
NS
PC3/TP1B_1/ TP1B_1
SCS/SSEG3/ SCS
KEY4
SSEG3
PD1/KEY14
O/T
TKMnC1
PC3
PD0/TCK2/
KEY13
I/T
SLCDCn
KEY3
PC6/TCK2/
PCK/SSEG6/
KEY7
Register
Select
Timer Module 2 input
CMOS Peripheral clock output
Software controlled LCD SEG
Touch key input
CMOS General purpose I/O. Register enabled pull-up.
MFI3
ST
—
SLCDCn
—
LCD
TKMnC1
NS
—
PDPU
ST
Peripheral interrupt input
Software controlled LCD SEG
Touch key input
CMOS General purpose I/O. Register enabled pull-up.
TCK2
TM2C0
ST
—
Timer Module 2 input
KEY13
TKMnC1
NS
—
Touch key input
PDPU
ST
TKMnC1
NS
PDPU
ST
TKMnC1
NS
PDPU
ST
TKMnC1
NS
PDPU
ST
TKMnC1
NS
PDPU
ST
TKMnC1
NS
PDPU
ST
TKMnC1
NS
PD1
KEY14
PD2
KEY15
PD3
KEY16
PD4
KEY17
PD5
KEY18
PD6
KEY19
CMOS General purpose I/O. Register enabled pull-up.
—
Touch key input
CMOS General purpose I/O. Register enabled pull-up.
—
Touch key input
CMOS General purpose I/O. Register enabled pull-up.
—
Touch key input
CMOS General purpose I/O. Register enabled pull-up.
—
Touch key input
CMOS General purpose I/O. Register enabled pull-up.
—
Touch key input
CMOS General purpose I/O. Register enabled pull-up.
—
Touch key input
15
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Pin Name
PD7/KEY20
PE0/PINT/
SSEG14
Function
PD7
KEY20
PE0
PINT
SSEG14
PE1
TP2_0
PE1/TP2_0/
PCK/SSEG15 PCK
SSEG15
PE2
PE2/TP2_1/
SCS/SSEG16
TP2_1
SCS
Register
Select
I/T
PDPU
ST
TKMnC1
NS
PEPU
ST
O/T
Description
CMOS General purpose I/O. Register enabled pull-up.
—
Touch key input
CMOS General purpose I/O. Register enabled pull-up.
MFI3
ST
—
SLCDCn
—
LCD
PEPU
ST
CMOS General purpose I/O. Register enabled pull-up.
TMPCn
ST
CMOS TM2 I/O
SIMC0
—
CMOS Peripheral Clock Output
SLCDCn
—
PEPU
ST
CMOS General purpose I/O. Register enabled pull-up.
TMPCn
ST
CMOS TM2 I/O
CMOS SPI select
LCD
Peripheral interrupt input
Software controlled LCD SEG
Software controlled LCD SEG
SIMC0
ST
SLCDCn
—
PE3
PEPU
ST
CMOS General purpose I/O. Register enabled pull-up.
SCK
PE3/SCK/
SCL/SSEG17 SCL
SIMC0
ST
CMOS SPI serial clock
SIMC0
ST
NMOS I2C clock
SSEG16
SLCDCn
—
PE4
SSEG17
PEPU
ST
SDI
PE4/SDI/
SDA/SSEG18 SDA
SIMC0
ST
SIMC0
ST
SSEG18
PE5/SDO/
SSEG19
PE5
SDO
SSEG19
LCD
LCD
Software controlled LCD SEG
Software controlled LCD SEG
CMOS General purpose I/O. Register enabled pull-up.
—
SPI data input
NMOS I2C data I/O
LCD
Software controlled LCD SEG
SLCDCn
—
PEPU
ST
CMOS General purpose I/O. Register enabled pull-up.
CMOS SPI data output
SIMC0
ST
SLCDCn
—
LCD
Software controlled LCD SEG
KEY9
KEY9
—
NS
—
Touch key input
KEY10
KEY10
—
NS
—
Touch key input
KEY11
KEY11
—
NS
—
Touch key input
KEY12
KEY12
—
NS
—
Touch key input
VDD
VDD
—
PWR
—
Power supply
VSS
VSS
—
PWR
—
Ground
Note: I/T: Input type
O/T: Output type
Register Select: Indicates register which selects alternative function
PWR: Power
ST: Schmitt Trigger input
CMOS: CMOS output
NMOS: NMOS output
LCD: LCD COM or SEG Vbias output
NS: Non-standard input or output
The pins in the table reflect that of the package with the largest number of pins. For this reason not all pins
may exist on all package types.
Rev. 1.40
16
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
BS85C20-5
Pin Name
PA0/SDI/SDA
Register
Select
I/T
PA0
PAWU
PAPU
ST
SDI
SIMC0
ST
SDA
SIMC0
ST
NMOS I2C data I/O
PA1
PAWU
PAPU
ST
CMOS General purpose I/O. Register enabled pull-up and wake-up.
TM1C0
ST
—
Timer Module 1 input
INTC0
ST
—
External interrupt 1 input
SLCDCn
—
LCD
PA2
PAWU
PAPU
ST
CMOS General purpose I/O. Register enabled pull-up and wake-up.
SCK
SIMC0
ST
CMOS SPI serial clock
SCL
SIMC0
ST
NMOS I2C clock
PA3
PAWU
PAPU
ST
CMOS General purpose I/O. Register enabled pull-up and wake-up.
SCS
SIMC0
ST
CMOS SPI slave select
PA4
PAWU
PAPU
ST
CMOS General purpose I/O. Register enabled pull-up and wake-up.
TM0C0
ST
—
Timer Module 0 input
INTC0
ST
—
External interrupt 0 input
SLCDCn
—
LCD
Software controlled LCD SEG
—
—
OSC
LXT Oscillator pin
—
LXT Oscillator pin
Function
PA1/TCK1/
TCK1
INT1/SSEG10
INT1
SSEG10
PA2/SCK/SCL
PA3/SCS
PA4/TCK0/
TCK0
INT0/SSEG11
INT0
SSEG11
OSC2
OSC2
OSC1
OSC1
PA7/SDO
PB0/TP0_0/
SCOM0
PB1/TP0_1/
TP2_0/
SCOM1
O/T
Description
CMOS General purpose I/O. Register enabled pull-up and wake-up.
—
SPI data input
Software controlled LCD SEG
—
OSC
PA7
PAWU
PAPU
ST
CMOS General purpose I/O. Register enabled pull-up and wake-up.
SDO
SIMC0
—
CMOS SPI data output
PB0
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up.
TP0_0
TMPCn
ST
CMOS TM0 I/O
SCOM0
SLCDCn
—
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up.
TP0_1
TMPCn
ST
CMOS TM0 I/O
TP2_0
TMPCn
ST
CMOS TM2 I/O
SCOM1
SLCDCn
—
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up.
TMPCn
ST
CMOS TM1 I/O
TMPCn
ST
CMOS TM2 I/O
SLCDCn
—
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up.
CMOS TM1 I/O
PB1
PB2
PB2/TP1B_0/ TP1B_0
TP2_1/
TP2_1
SCOM2
SCOM2
PB3
PB3/TP1B_1/
TP1B_1
SCOM3
SCOM3
LCD
LCD
LCD
Software controlled LCD COM
Software controlled LCD COM
Software controlled LCD COM
TMPCn
ST
SLCDCn
—
PBPU
ST
CMOS General purpose I/O. Register enabled pull-up.
PB4/TP1B_2/ TP1B_2
PCK/SSEG8 PCK
TMPCn
ST
CMOS TM1 I/O
SIMC0
—
CMOS Peripheral clock output
SSEG8
SLCDCn
—
PB4
Rev. 1.40
LCD
LCD
Software controlled LCD COM
Software controlled LCD SEG
17
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Pin Name
Function
PBPU
ST
PINT
MFI3
ST
TMPCn
ST
SSEG9
PB7/SSEG21
PB6
SSEG20
PB7
SSEG21
PC0
TP0_0
PC0/TP0_0/
SDO/SSEG0/ SDO
KEY1
SSEG0
KEY1
PC1
TP0_1
PC1/TP0_1/
SCK
SCK/SCL/
SSEG1/KEY2 SCL
SSEG1
KEY2
PC2
TP1B_0
PC2/TP1B_0/ SDI
SDI/SDA/
SSEG2/KEY3 SDA
SSEG2
KEY3
PC3
PC3/TP1B_1/ TP1B_1
SCS/SSEG3/ SCS
KEY4
SSEG3
KEY4
PC4
TCK0
PC4/TCK0/
INT0
INT0/TP1B_2/
SSEG4/KEY5 TP1B_2
SSEG4
KEY5
PC5
TCK1
PC5/TCK1/
INT1
INT1/TP1A/
SSEG5/KEY6 TP1A
SSEG5
Rev. 1.40
SLCDCn
—
PBPU
ST
SLCDCn
—
PBPU
ST
O/T
Description
CMOS General purpose I/O. Register enabled pull-up.
—
Peripheral interrupt input
CMOS TM1 I/O
LCD
Software controlled LCD SEG
CMOS General purpose I/O. Register enabled pull-up.
LCD
Software controlled LCD SEG
CMOS General purpose I/O. Register enabled pull-up.
SLCDCn
—
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
LCD
TMPCn
ST
CMOS TM0 I/O
SIMC0
—
CMOS SPI data output
Software controlled LCD SEG
Software controlled LCD SEG
SLCDCn
—
LCD
TKMnC1
NS
—
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
TMPCn
ST
CMOS TM0 I/O
SIMC0
ST
CMOS SPI clock
SIMC0
ST
NMOS I2C clock
SLCDCn
—
TKMnC1
NS
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
TMPCn
ST
CMOS TM1 I/O
SIMC0
ST
SIMC0
ST
LCD
—
—
Touch key input
Software controlled LCD SEG
Touch key input
SPI data input
NMOS I2C data I/O
SLCDCn
—
LCD
TKMnC1
NS
—
Software controlled LCD SEG
Touch key input
PCPU
ST
CMOS General purpose I/O. Register enabled pull-up.
TMPCn
ST
CMOS TM1 I/O
SIMC0
ST
CMOS SPI slave select
SLCDCn
—
LCD
TKMnC1
NS
—
PCPU
ST
TM0C0
ST
—
Timer Module 0 input
INTC0
ST
—
External interrupt 0 input
Software controlled LCD SEG
Touch key input
CMOS General purpose I/O. Register enabled pull-up.
TMPCn
ST
SLCDCn
—
CMOS TM1 I/O
LCD
TKMnC1
NS
—
PCPU
ST
TM1C0
ST
—
Timer Module 1 input
INTC0
ST
—
External interrupt 1 input
TMPCn
ST
Software controlled LCD SEG
Touch key input
CMOS General purpose I/O. Register enabled pull-up.
CMOS TM1 I/O
SLCDCn
—
LCD
TKMnC1
NS
—
PC6
PCPU
ST
TCK2
TM2C0
ST
PCK
SIMC0
—
KEY6
PC6/TCK2/
PCK/SSEG6/
KEY7
I/T
PB5
PB5/PINT/
TP1A/SSEG9 TP1A
PB6/SSEG20
Register
Select
Software controlled LCD SEG
Touch key input
CMOS General purpose I/O. Register enabled pull-up.
—
Timer Module 2 input
CMOS Peripheral clock output
SSEG6
SLCDCn
—
LCD
KEY7
TKMnC1
NS
—
Software controlled LCD SEG
Touch key input
18
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Pin Name
Register
Select
I/T
PC7
PCPU
ST
PINT
MFI3
ST
—
SLCDCn
—
LCD
TKMnC1
NS
PDPU
ST
Function
PC7/PINT/
SSEG7/KEY8 SSEG7
KEY8
PD0/TCK2/
KEY13
PD1/KEY14
PD2/KEY15
PD3/KEY16
PD4/KEY17
PD5/KEY18
PD6/KEY19
PD7/KEY20
PE0/PINT/
SSEG14
PD0
O/T
Description
CMOS General purpose I/O. Register enabled pull-up.
—
Peripheral interrupt input
Software controlled LCD SEG
Touch key input
CMOS General purpose I/O. Register enabled pull-up.
TCK2
TM2C0
ST
—
Timer Module 2 input
KEY13
TKMnC1
NS
—
Touch key input
PDPU
ST
TKMnC1
NS
PDPU
ST
TKMnC1
NS
PDPU
ST
TKMnC1
NS
PDPU
ST
TKMnC1
NS
PDPU
ST
TKMnC1
NS
PD1
KEY14
PD2
KEY15
PD3
KEY16
PD4
KEY17
PD5
KEY18
PD6
KEY19
PD7
KEY20
PE0
PINT
SSEG14
PE1
TP2_0
PE1/TP2_0/
PCK/SSEG15 PCK
SSEG15
PE2
TP2_1
PE2/TP2_1/
SCS/SSEG16 SCS
SSEG16
PDPU
ST
TKMnC1
NS
PDPU
ST
TKMnC1
NS
PEPU
ST
CMOS General purpose I/O. Register enabled pull-up.
—
Touch key input
CMOS General purpose I/O. Register enabled pull-up.
—
Touch key input
CMOS General purpose I/O. Register enabled pull-up.
—
Touch key input
CMOS General purpose I/O. Register enabled pull-up.
—
Touch key input
CMOS General purpose I/O. Register enabled pull-up.
—
Touch key input
CMOS General purpose I/O. Register enabled pull-up.
—
Touch key input
CMOS General purpose I/O. Register enabled pull-up.
—
Touch key input
CMOS General purpose I/O. Register enabled pull-up.
MFI3
ST
—
SLCDCn
—
LCD
PEPU
ST
CMOS General purpose I/O. Register enabled pull-up.
TMPCn
ST
CMOS TM2 I/O
SIMC0
—
CMOS Peripheral Clock Output
SLCDCn
—
PEPU
ST
CMOS General purpose I/O. Register enabled pull-up.
TMPCn
ST
CMOS TM2 I/O
SIMC0
ST
CMOS SPI select
SLCDCn
—
LCD
LCD
Peripheral interrupt input
Software controlled LCD SEG
Software controlled LCD SEG
Software controlled LCD SEG
PE3
PEPU
ST
CMOS General purpose I/O. Register enabled pull-up.
SCK
PE3/SCK/
SCL/SSEG17 SCL
SIMC0
ST
CMOS SPI serial clock
SIMC0
ST
NMOS I2C clock
SLCDCn
—
PE4
SSEG17
PEPU
ST
SDI
PE4/SDI/
SDA/SSEG18 SDA
SIMC0
ST
SIMC0
ST
SLCDCn
—
SSEG18
PE5/SDO/
SSEG19
LCD
Software controlled LCD SEG
CMOS General purpose I/O. Register enabled pull-up.
—
SPI data input
NMOS I2C data I/O
LCD
Software controlled LCD SEG
PE5
PEPU
ST
CMOS General purpose I/O. Register enabled pull-up.
SDO
SIMC0
ST
CMOS SPI data output
SLCDCn
—
LCD
SSEG19
Software controlled LCD SEG
KEY9
KEY9
—
NS
—
Touch key input
KEY10
KEY10
—
NS
—
Touch key input
KEY11
KEY11
—
NS
—
Touch key input
KEY12
KEY12
—
NS
—
Touch key input
Rev. 1.40
19
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Pin Name
Function
Register
Select
I/T
O/T
Description
VDD
VDD
—
PWR
—
Power supply
VSS
VSS
—
PWR
—
Ground
Note: I/T: Input type
O/T: Output type
Register Select: Indicates register which selects alternative function
PWR: Power
ST: Schmitt Trigger input
CMOS: CMOS output
NMOS: NMOS output
LCD: LCD COM or SEG Vbias output
NS: Non-standard input or output
The pins in the table reflect that of the package with the largest number of pins. For this reason not all pins
may exist on all package types.
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...................................................................................................................................-100mA
IOL Total.................................................................................................................................... 100mA
Total Power Dissipation ......................................................................................................... 500mW
Note: These are stress ratings only. Stresses exceeding the range specified under "Absolute Maximum
Ratings" may cause substantial damage to these devices. Functional operation of these devices at
other conditions beyond those listed in the specification is not implied and prolonged exposure to
extreme conditions may affect devices reliability.
Rev. 1.40
20
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
D.C. Characteristics
Ta= 25˚C
Symbol
VDD
Parameter
Operating Voltage (HIRC)
Test Conditions
VDD
—
3V
5V
IDD1
Operating Current (HIRC),
(fSYS=fH)
3V
5V
5V
IDD2
Operating Current (LIRC),
(fSYS=fL)
IIDLE01
IDLE0 Mode Standby Current
(LXT on)
3V
5V
3V
5V
3V
5V
IIDLE02
IDLE0 Mode Standby Current
(LIRC on)
3V
5V
3V
IIDLE03
IDLE0 Mode Standby Current
(LXT and LIRC on)
5V
3V
5V
IIDLE1
ISLEEP
IDLE1 Mode Standby Current
SLEEP1 Mode Standby Current
3V
5V
3V
5V
VIL
Input Low Voltage for I/O Ports or
Input Pins
5V
VIH
Input High Voltage for I/O Ports or
Input Pins
5V
Conditions
Min.
Typ.
Max.
Unit
fSYS=8MHz
VLVR
—
5.5
V
fSYS=12MHz
2.7
—
5.5
V
fSYS=16MHz
4.5
—
5.5
V
No load, fH=8MHz,
WDT enable
—
1.2
1.8
mA
—
2.7
4.1
mA
No load, fH=12MHz,
WDT enable
—
1.9
2.9
mA
—
4.2
6.3
mA
—
5.6
8.4
mA
—
15
30
µA
—
30
50
µA
No load, fH=16MHz,
WDT enable
No load, fL=32kHz,
WDT enable
No load, WDT enable,
LXTLP=0
—
5
10
µA
—
18
30
µA
No load, WDT enable,
LXTLP=1
—
2.5
5.0
µA
—
6
10
µA
—
1.5
3.0
µA
—
3.0
6.0
µA
No load, WDT enable,
LXTLP=0
—
6.5
13
µA
—
13
26
µA
No load, WDT enable,
LXTLP=1
—
6
12
µA
—
12
24
µA
No load, LVR disable,
fSYS=12MHz on
—
0.9
1.4
mA
—
1.6
2.4
mA
—
1.5
3.0
µA
—
2.5
5.0
µA
0
—
1.5
V
No load, LVR disable
No load, LVR disable
—
—
—
—
0
—
0.2VDD
V
3.5
—
5.0
V
0.8VDD
—
VDD
V
3V
IOL=9mA
—
—
0.3
V
5V
IOL=20mA
—
—
0.5
V
3V
IOL=18mA
—
—
0.3
V
5V
IOL=40mA
—
—
0.5
V
3V
IOH=-3.2mA
2.7
—
—
V
5V
IOH=-7.4mA
4.5
—
—
V
V
VOL1
Output Low Voltage I/O Port
VOL2
Output Low Voltage I/O Port
(PB) (High Current Enable)
VOH1
Output High Voltage I/O Port
VOH2
Output High Voltage I/O Port
(PA, PE) (High Current Enable)
3V
IOH=-6.4mA
2.7
—
—
5V
IOH=-15.0mA
4.5
—
—
V
VLVR
LVR Voltage Level
—
LVR Enable
-5%
2.55
+5%
V
LVDEN=1, VLVD=2.7V
-5%
2.70
+5%
V
LVDEN=1, VLVD=3.0V
-5%
3.00
+5%
V
LVDEN=1, VLVD=3.3V
-5%
3.30
+5%
V
LVDEN=1, VLVD=3.6V
-5%
3.60
+5%
V
LVDEN=1, VLVD=4.2V
-5%
4.20
+5%
V
NORMAL or SLOW Mode
—
2
5
µA
IDLE or SLEEP Mode
—
15
30
µA
VLVD
ILVD
Rev. 1.40
LVD Voltage Level
Additional Power Consumption if
LVD is Used
—
—
21
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Symbol
ISCOM
ISSEG
VSSOM
VSSEG
RPH
Parameter
SCOM Operating Current
SSEG Operating Current
Voltage for LCD SCOM
Voltage for LCD SSEG
Pull-high Resistance for I/O Ports
Test Conditions
Min.
Typ.
Max.
Unit
ISEL[1:0]=00
17.5
25.0
32.5
µA
ISEL[1:0]=01
35
50
65
µA
ISEL[1:0]=10
70
100
130
µA
ISEL[1:0]=11
140
200
260
µA
ISEL[1:0]=00
17.5
25.0
32.5
µA
ISEL[1:0]=01
35
50
65
µA
ISEL[1:0]=10
70
100
130
µA
ISEL[1:0]=11
140
200
260
µA
1/3 VDD
-3%
0.33
+3%
VDD
2/3 VDD
-3%
0.67
+3%
VDD
1/3 VDD
-3%
0.33
+3%
VDD
2/3 VDD
-3%
0.67
+3%
VDD
20
60
100
kΩ
10
30
50
kΩ
VDD
5V
5V
5V
5V
Conditions
3V
—
5V
A.C. Characteristics
Ta= 25˚C
Symbol
fCPU
Parameter
Operating Clock
Test Conditions
Min.
Typ.
VLVR~5.5V
DC
2.7V~5.5V
DC
VDD
—
Conditions
4.5V~5.5V
Rev. 1.40
—
8
MHz
—
12
MHz
DC
—
16
MHz
-2%
8
+2%
MHz
3V/5V Ta=25˚C
-2%
12
+2%
MHz
-2%
16
+2%
MHz
3V/5V Ta=0~70˚C
-4%
8
+3%
MHz
3V/5V Ta=0~70˚C
-4%
12
+3%
MHz
Ta=0~70˚C
-4%
16
+3%
MHz
2.5V~
Ta=0~70˚C
4.0V
-9%
8
+6%
MHz
3.0V~
Ta=0~70˚C
5.5V
-5%
8
+12%
MHz
2.7V~
Ta=0~70˚C
4.0V
-9%
12
+5%
MHz
3.0V~
Ta=0~70˚C
5.5V
-5%
12
+11%
MHz
4.5V~
Ta=0~70˚C
5.5V
-5%
16
+5%
MHz
2.5V~
Ta=-40˚C~85˚C
4.0V
-12%
8
+6%
MHz
3.0V~
Ta=-40˚C~85˚C
5.5V
-8%
8
+12%
MHz
2.7V~
Ta=-40˚C~85˚C
4.0V
-13%
12
+5%
MHz
3.0V~
Ta=-40˚C~85˚C
5.5V
-8%
12
+11%
MHz
4.5V~
Ta=-40˚C~85˚C
5.5V
-7%
16
+5%
MHz
5V
System Clock (HIRC)
Unit
3V/5V Ta=25˚C
5V
fHIRC
Max.
Ta=25˚C
22
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Symbol
Test Conditions
Parameter
fLIRC
System Clock (LIRC)
VDD
Conditions
5V
—
2.2V~
Ta=-40˚C~85˚C
5.5V
Min.
Typ.
Max.
Unit
-10%
32
+10%
kHz
-50%
32
+60%
kHz
fSYS
fTIMER
Timer Input Pin Frequency
—
—
—
—
1
tINT
Interrupt Pulse Width
—
—
1
—
—
µs
tLVR
Low Voltage Width to Reset
—
—
60
120
240
µs
µs
tLVD
Low Voltage Width to Interrupt
—
—
180
240
360
tLVDS
LVDO Stable Time
—
—
15
—
—
µs
tEERD
EEPROM Read Time
—
—
—
2
4
tSYS
tEEWR
EEPROM Write Time
—
—
—
2
4
ms
tSST
System Start-up Timer Period
(Wake-up from HALT)
—
fSYS=HIRC
—
15~16
—
fSYS=LIRC
—
1~2
—
tSYS
Note: 1. tSYS=1/fSYS
2. To maintain the accuracy of the internal HIRC oscillator frequency, a 0.1µF decoupling capacitor
should be connected between VDD and VSS and located as close to the device as possible.
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
RPOR AC
VDD Raising Rate to Ensure
Power-on Reset
—
—
0.035
—
—
V/ms
tPOR
Minimum Time for VDD Stays at
VPOR to Ensure Power-on Reset
—
—
1
—
—
ms
Rev. 1.40
23
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Oscillator Temperature/Frequency Characteristics
The following characteristic graphics depicts typical oscillator behavior. The data presented here is
a statistical summary of data gathered on units from different lots over a period of time. This is for
information only and the figures were not tested during manufacturing.
In some of the graphs, the data exceeding the specified operating range are shown for information
purposes only. The device will operate properly only within the specified range.
Internal RC -- 8MHz (3V)
8.300
8.200
8.100
fSYS (MHz)
8.000
7.900
2.5V
2.7V
3.0V
4.0V
7.800
7.700
7.600
7.500
7.400
7.300
-60
-40
-20
0
20
40
60
80
100
120
140
Ta(°C)
Internal RC -- 8MHz (5V)
8.800
8.600
fSYS (MHz)
8.400
3.0V
4.0V
4.5V
4.75V
5.0V
5.25V
5.5V
8.200
8.000
7.800
7.600
7.400
-60
-40
-20
0
20
40
60
80
100
120
140
Ta(°C)
Rev. 1.40
24
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Internal RC -- 12MHz (3V)
12.400
12.200
12.000
fSYS (MHz)
11.800
2.7V
3.0V
4.0V
11.600
11.400
11.200
11.000
10.800
-60
-40
-20
0
20
40
60
80
100
120
140
Ta(°C)
Internal RC -- 12MHz (5V)
13.000
12.800
12.600
3.0V
4.0V
4.5V
4.75V
5.0V
5.25V
5.5V
fSYS (MHz)
12.400
12.200
12.000
11.800
11.600
11.400
-60
-40
-20
0
20
40
60
80
100
120
140
Ta(°C)
Rev. 1.40
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BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Internal RC -- 16MHz (5V)
16.400
16.300
16.200
16.100
fSYS (MHz)
16.000
4.5V
4.75V
5.0V
5.25V
5.5V
15.900
15.800
15.700
15.600
15.500
15.400
15.300
-60
-40
-20
0
20
40
60
80
100
120
140
Ta(°C)
System Architecture
A key factor in the high-performance features of the Holtek range of microcontroller is attributed to
their internal system architecture. The range of devices take advantage of the usual features found
within RISC microcontroller providing increased speed of operation and enhanced performance. The
pipelining scheme is implemented in such a way that instruction fetching and instruction execution
are overlapped, hence instructions are effectively executed in one cycle, with the exception of branch
or call instructions. An 8-bit wide ALU is used in practically all instruction set operations, which
carries out arithmetic operations, logic operations, rotation, increment, decrement, branch decisions,
etc. The internal data path is simplified by moving data through the Accumulator and the ALU.
Certain internal registers are implemented in the Data Memory and can be directly or indirectly
addressed. The simple addressing methods of these registers along with additional architectural
features ensure that a minimum of external components is required to provide a functional I/O
control system with maximum reliability and flexibility. This makes the device suitable for low-cost,
high-volume production for controller applications.
Clocking and Pipelining
The main system clock, derived from either a high or low speed 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.
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Touch Key Flash MCU with LCD/LED Driver

System Clocking and Pipelining

Instruction Fetching
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.
Program Counter
During program execution, the Program Counter is used to keep track of the address of the next
instruction to be executed. It is automatically incremented by one each time an instruction is
executed except for instructions, such as "JMP" or "CALL" that demand a jump to a non-consecutive
Program Memory address. Only the lower 8 bits, known as the Program Counter Low Register, are
directly addressable by the application program.
When executing instructions requiring jumps to non-consecutive addresses such as a jump instruction,
a subroutine call, interrupt or reset, etc., the microcontroller manages program control by loading the
required address into the Program Counter. For conditional skip instructions, once the condition has
been met, the next instruction, which has already been fetched during the present instruction execution,
is discarded and a dummy cycle takes its place while the correct instruction is obtained.
The lower byte of the Program Counter, known as the Program Counter Low register or PCL, is
available for program control and is a readable and writeable register. By transferring data directly
into this register, a short program jump can be executed directly, however, as only this low byte
is available for manipulation, the jumps are limited to the present page of memory, that is 256
locations. When such program jumps are executed it should also be noted that a dummy cycle
will be inserted. Manipulating the PCL register may cause program branching, so an extra cycle is
needed to pre-fetch.
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Touch Key Flash MCU with LCD/LED Driver
Stack
This is a special part of the memory which is used to save the contents of the Program Counter only.
The stack has multiple levels depending upon the device and is neither part of the data nor part of
the program space, and is neither readable nor writeable. The activated level is indexed by the Stack
Pointer, and is neither readable nor writeable. At a subroutine call or interrupt acknowledge signal, the
contents of the Program Counter are pushed onto the stack. At the end of a subroutine or an interrupt
routine, signaled by a return instruction, RET or RETI, the Program Counter is restored to its previous
value from the stack. After a device reset, the Stack Pointer will point to the top of the stack.
If the stack is full and an enabled interrupt takes place, the interrupt request flag will be recorded but
the acknowledge signal will be inhibited. When the Stack Pointer is decremented, by RET or RETI,
the interrupt will be serviced. This feature prevents stack overflow allowing the programmer to use
the structure more easily. However, when the stack is full, a CALL subroutine instruction can still
be executed which will result in a stack overflow. Precautions should be taken to avoid such cases
which might cause unpredictable program branching.
If the stack is overflow, the first Program Counter save in the stack will be lost.
Device
Stack Levels
BS85B12-3
4
BS85C20-3
/BS85C20-5
8
P ro g ra m
T o p o f S ta c k
S ta c k L e v e l 1
S ta c k L e v e l 2
S ta c k
P o in te r
B o tto m
C o u n te r
S ta c k L e v e l 3
o f S ta c k
P ro g ra m
M e m o ry
S ta c k L e v e l N
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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BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Flash Program Memory
The Program Memory is the location where the user code or program is stored. For this device
series 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, these Flash devices 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 2K×15 bits or 4K×15 bits. The Program Memory is
addressed by the Program Counter and also contains data, table information and interrupt entries.
Table data, which can be setup in any location within the Program Memory, is addressed by a
separate table pointer register.
Device
Capacity
BS85B12-3
2K×15
BS85C20-3
/BS85C20-5
4K×15
Special Vectors
Within the Program Memory, certain locations are reserved for the reset and interrupts. The location
000H is reserved for use by the device reset for program initialisation. After a device reset is
initiated, the program will jump to this location and begin execution.
Look-up Table
Any location within the Program Memory can be defined as a look-up table where programmers can
store fixed data. To use the look-up table, the table pointer must first be setup by placing the address
of the look up data to be retrieved in the table pointer register, TBLP and TBHP. These registers
define the total address of the look-up table.
After setting up the table pointer, the table data can be retrieved from the Program Memory using
the "TABRD[m]" or "TABRDL[m]" instructions, respectively. When the instruction is executed,
the lower order table byte from the Program Memory will be transferred to the user defined
Data Memory register [m] as specified in the instruction. The higher order table data byte from
the Program Memory will be transferred to the TBLH special register. Any unused bits in this
transferred higher order byte will be read as "0".
The accompanying diagram illustrates the addressing data flow of the look-up table.
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Touch Key Flash MCU with LCD/LED Driver
A d d re s s
L a s t p a g e o r
T B H P R e g is te r
T B L P R e g is te r
D a ta
1 5 b its
R e g is te r T B L H
U s e r S e le c te d
R e g is te r
H ig h B y te
L o w B y te
Table Program Example
The following example using the BS85B12-3 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 "700H"
which refers to the start address of the last page within the 2K words Program Memory of the device.
The table pointer is setup here to have an initial value of "06H". This will ensure that the first data
read from the data table will be at the Program Memory address "706H" or 6 locations after the
start of the last page. Note that the value for the table pointer is referenced to the first address of the
present page if the "TABRD [m]" instruction is being used. The high byte of the table data which in
this case is equal to zero will be transferred to the TBLH register automatically when the "TABRD [m]"
instruction is executed.
Because the TBLH register is a read-only register and cannot be restored, care should be taken
to ensure its protection if both the main routine and Interrupt Service Routine use table read
instructions. If using the table read instructions, the Interrupt Service Routines may change the
value of the TBLH and subsequently cause errors if used again by the main routine. As a rule it is
recommended that simultaneous use of the table read instructions should be avoided. However, in
situations where simultaneous use cannot be avoided, the interrupts should be disabled prior to the
execution of any main routine table-read instructions. Note that all table related instructions require
two instruction cycles to complete their operation.
Tempreg1db ? ; temporary register #1
tempreg2db ? ; temporary register #2
:
:
mov a,06h ; initialise low table pointer - note that this address
mov tblp,a ; is referenced
mov a,07h ; initialise high table pointer
mov tbhp,a
:
:
tabrd tempreg1 ; transfers value in table referenced by table pointer data at
; program memory address "706H" transferred to tempreg1 and TBLH
dec tblp ; reduce value of table pointer by one
tabrd tempreg2 ;
;
;
;
:
:
org 700h ;
transfers value in table referenced by table pointer data at
program memory address "705H" transferred to tempreg2 and TBLH in
this example the data "1AH" is transferred to tempreg1 and data
"0FH" to register tempreg2
sets initial address of program memory
dc 00Ah, 00Bh, 00Ch, 00Dh, 00Eh, 00Fh, 01Ah, 01Bh
:
:
Rev. 1.40
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BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
In Circuit Programming
The provision of Flash type Program Memory provides the user with a means of convenient and
easy upgrades and modifications to their programs on the same device.
As an additional convenience, Holtek has provided a means of programming the microcontroller incircuit using a 5-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.
The Holtek Flash MCU to Writer Programming Pin correspondence table is as follows:
Holtek Writer
Device
Pin Name
Pin Name
SDATA
PA0
Serial Address and data -- read/write
SCLK
PA2
Address and data serial clock input
VPP
PA7
Reset input
VDD
VDD
Power Supply (5.0V)
VSS
VSS
Ground
Pin Description
The Program Memory and EEPROM data memory can both be programmed serially in-circuit using
this 5-wire interface. Data is downloaded and uploaded serially on a single pin with an additional
line for the clock. Two additional lines are required for the power supply and one line for the reset.
The technical details regarding the in-circuit programming of the devices are beyond the scope of
this document and will be supplied in supplementary literature.
During the programming process the PA7 pin will be held low by the programmer disabling the
normal operation of the microcontroller and taking control of the PA0 and PA2 I/O pins for data
and clock programming purposes. The user must there take care to ensure that no other outputs are
connected to these two pins.
W r ite r C o n n e c to r
S ig n a ls
M C U
V D D
V D D
V P P
P A 7
S D A T A
P A 0
S C L K
P A 2
V S S
V S S
*
*
P r o g r a m m in g
P in s
*
T o o th e r C ir c u it
Note: * may be resistor or capacitor. The resistance of * must be greater than 1k or the capacitance
of * must be less than 1nF.
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Touch Key Flash MCU with LCD/LED Driver
RAM Data Memory
The Data Memory is a volatile area of 8-bit wide RAM internal memory and is the location where
temporary information is stored.
Structure
Divided into two sections, the first of these is an area of RAM, known as the Special Function Data
Memory. Here are located registers which are necessary for correct operation of the device. Many
of these registers can be read from and written to directly under program control, however, some
remain protected from user manipulation.
Device
Capacity
Bank 0
Bank 1
Bank 2
BS85B12-3
256×8
80H~FFH
80H~FFH
—
BS85C20-3
/BS85C20-5
384×8
80H~FFH
80H~FFH
80H~FFH
General Purpose Data Memory
The second area of Data Memory is known as the General Purpose Data Memory, which is reserved
for general purpose use. All locations within this area are read and write accessible under program
control.
The overall Data Memory is subdivided into two or three banks. The Special Purpose Data Memory
registers are accessible in all banks, with the exception of the EEC register at address 40H, which
is only accessible in Bank 1. Switching between the different Data Memory banks is achieved by
setting the Bank Pointer to the correct value. The start address of the Data Memory for all devices is
the address 00H.
Special Function Register Description
Most of the Special Function Register details will be described in the relevant functional section,
however several registers require a separate description in this section.
Indirect Addressing Registers – IAR0, IAR1
The Indirect Addressing Registers, IAR0 and IAR1, although having their locations in normal RAM
register space, do not actually physically exist as normal registers. The method of indirect addressing
for RAM data manipulation uses these Indirect Addressing Registers and Memory Pointers, in
contrast to direct memory addressing, where the actual memory address is specified. Actions on the
IAR0 and IAR1 registers will result in no actual read or write operation to these registers but rather
to the memory location specified by their corresponding Memory Pointers, MP0 or MP1. Acting as a
pair, IAR0 and MP0 can together access data from Bank 0 while the IAR1 and MP1 register pair can
access data from any bank. As the Indirect Addressing Registers are not physically implemented,
reading the Indirect Addressing Registers indirectly will return a result of "00H" and writing to the
registers indirectly will result in no operation.
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BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Memory Pointers – MP0, MP1
Two Memory Pointers, known as MP0 and MP1 are provided. These Memory Pointers are
physically implemented in the Data Memory and can be manipulated in the same way as normal
registers providing a convenient way with which to address and track data. When any operation to
the relevant Indirect Addressing Registers is carried out, the actual address that the microcontroller
is directed to, is the address specified by the related Memory Pointer. MP0, together with Indirect
Addressing Register, IAR0, are used to access data from Bank 0, while MP1 and IAR1 are used to
access data from all banks according to BP register. Direct Addressing can only be used with Bank
0, all other Banks must be addressed indirectly using MP1 and IAR1. Note that for this series of
devices, the Memory Pointers, MP0 and MP1, are both 8-bit registers and used to access the Data
Memory together with their corresponding indirect addressing registers IAR0 and IAR1.
The following example shows how to clear a section of four Data Memory locations already defined
as locations adres1 to adres4.
Indirect Addressing Program Example
data .section ”data“
adres1 db ?
adres2 db ?
adres3 db ?
adres4 db ?
block db ?
code .section at 0 ”code“
org 00h
start:
mov a,04h ; setup size of block
mov block,a
mov a,offset adres1; Accumulator loaded with first RAM address
mov mp0,a ; setup memory pointer with first RAM address
loop:
clr IAR0 ; clear the data at address defined by MP0
inc mp0 ; increment memory pointer
sdz block ; check if last memory location has been cleared
jmp loop
continue:
The important point to note here is that in the example shown above, no reference is made to specific
RAM addresses.
Rev. 1.40
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Touch Key Flash MCU with LCD/LED Driver

Special Purpose Data Memory
Note: The Reserved bytes shown in the table must not be modified by the user.
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Touch Key Flash MCU with LCD/LED Driver
General Purpose Data Memory
Bank Pointer – BP
For this series of devices, the Data Memory is divided into two or three banks. Selecting the required
Data Memory area is achieved using the Bank Pointer. Bit 0 and 1 is used to select Data Memory
Banks 0~2.
The Data Memory is initialised to Bank 0 after a reset, except for a WDT time-out reset in the Power
Down Mode, in which case, the Data Memory bank remains unaffected. It should be noted that the
Special Function Data Memory is not affected by the bank selection, which means that the Special
Function Registers can be accessed from within any bank. Directly addressing the Data Memory
will always result in Bank 0 being accessed irrespective of the value of the Bank Pointer. Accessing
data from banks other than Bank 0 must be implemented using indirect addressing.
BP Register – BS85B12-3
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
—
—
—
DMBP0
R/W
—
—
—
—
—
—
—
R/W
POR
—
—
—
—
—
—
—
0
3
2
1
0
Bit 7~1
unimplemented, read as "0"
Bit 0
DMBP0: select data memory banks
0: bank 0
1: bank 1
BP Register – BS85C20-3/BS85C20-5
Bit
Rev. 1.40
7
6
5
4
Name
—
—
—
—
—
—
DMBP1
DMBP0
R/W
—
—
—
—
—
—
R/W
R/W
POR
—
—
—
—
—
—
0
0
Bit 7~2
unimplemented, read as "0"
Bit 1~0
DMBP1, DMBP0: select data memory banks
00: bank 0
01: bank 1
10: bank 2
11: undefined
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Touch Key Flash MCU with LCD/LED Driver
Accumulator – ACC
The Accumulator is central to the operation of any microcontroller and is closely related with
operations carried out by the ALU. The Accumulator is the place where all intermediate results
from the ALU are stored. Without the Accumulator it would be necessary to write the result of
each calculation or logical operation such as addition, subtraction, shift, etc., to the Data Memory
resulting in higher programming and timing overheads. Data transfer operations usually involve
the temporary storage function of the Accumulator; for example, when transferring data between
one user defined register and another, it is necessary to do this by passing the data through the
Accumulator as no direct transfer between two registers is permitted.
Program Counter Low Register – PCL
To provide additional program control functions, the low byte of the Program Counter is made
accessible to programmers by locating it within the Special Purpose area of the Data Memory. By
manipulating this register, direct jumps to other program locations are easily implemented. Loading
a value directly into this PCL register will cause a jump to the specified Program Memory location,
however, as the register is only 8-bit wide, only jumps within the current Program Memory page are
permitted. When such operations are used, note that a dummy cycle will be inserted.
Look-up Table Registers – TBLP, TBHP, TBLH
These three special function registers are used to control operation of the look-up table which is
stored in the Program Memory. TBLP and TBHP are the table pointer and indicates the location
where the table data is located. Their value must be setup before any table read commands are
executed. Their value can be changed, for example using the "INC" or "DEC" instructions, allowing
for easy table data pointing and reading. TBLH is the location where the high order byte of the table
data is stored after a table read data instruction has been executed. Note that the lower order table
data byte is transferred to a user defined location.
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.
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Touch Key Flash MCU with LCD/LED Driver
• 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
Rev. 1.40
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
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 C is also affected by a rotate through carry instruction.
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EEPROM Data Memory
The devices contain an area of internal EEPROM Data Memory. EEPROM, which stands for
Electrically Erasable Programmable Read Only Memory, is by its nature a non-volatile form
of 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 64×8 or 128×8 bits for this series of devices. Unlike the
Program Memory and RAM Data Memory, the EEPROM Data Memory is not directly mapped
into memory space and is therefore not directly addressable in the same way as the other types of
memory. Read and Write operations to the EEPROM are carried out in single byte operations using
an address and data register in Bank 0 and a single control register in Bank 1.
Device
Capacity
Address
BS85B12-3
64×8
00H ~ 3FH
BS85C20-3
/BS85C20-5
128×8
00H ~ 7FH
EEPROM Registers
Three registers control the overall operation of the internal EEPROM Data Memory. These are the
address register, EEA, the data register, EED and a single control register, EEC. As both the EEA
and EED registers are located in Bank 0, they can be directly accessed in the same was as any other
Special Function Register. The EEC register however, being located in Bank1, cannot be addressed
directly and can only be read from or written to indirectly using the MP1 Memory Pointer and
Indirect Addressing Register, IAR1. Because the EEC control register is located at address 40H in
Bank 1, the MP1 Memory Pointer must first be set to the value 40H and the Bank Pointer register,
BP, set to the value, 01H, before any operations on the EEC register are executed.
EEPROM Register List
• BS85B12-3
Name
Bit
7
6
5
4
3
2
1
0
EEA
—
—
D5
D4
D3
D2
D1
D0
EED
D7
D6
D5
D4
D3
D2
D1
D0
EEC
—
—
—
—
WREN
WR
RDEN
RD
6
5
4
3
2
1
0
• BS85C20-3/BS85C20-5
Name
Rev. 1.40
Bit
7
EEA
—
D6
D5
D4
D3
D2
D1
D0
EED
D7
D6
D5
D4
D3
D2
D1
D0
EEC
—
—
—
—
WREN
WR
RDEN
RD
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BS85B12-3/BS85C20-3/BS85C20-5
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EEA Register
• BS85B12-3
Bit
7
6
5
4
3
2
1
0
Name
—
—
D5
D4
D3
D2
D1
D0
R/W
—
—
R/W
R/W
R/W
R/W
R/W
R/W
POR
—
—
x
x
x
x
x
x
"x" unknown
Bit 7~6
unimplemented, read as "0"
Bit 5~0
Data EEPROM address
Data EEPROM address bit 5~bit 0
• BS85C20-3/BS85C20-5
Bit
7
6
5
4
3
2
1
0
Name
—
D6
D5
D4
D3
D2
D1
D0
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" unknown
Bit 7
unimplemented, read as "0"
Bit 6~0
Data EEPROM address
Data EEPROM address bit 6~bit 0
EEC Register
Rev. 1.40
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.
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March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
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: The WREN, WR, RDEN and RD can not be set to "1" at the same time in one
instruction. The WR and RD can not be set to "1" at the same time.
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
x
x
x
x
x
x
x
x
"x" unknown
Bit 7~0
Data EEPROM data
Data EEPROM data bit 7~bit 0
Reading Data from the EEPROM
To read data from the EEPROM, the read enable bit, RDEN, in the EEC register must first be set high
to enable the read function. The EEPROM address of the data to be read must then be placed in the
EEA register. If the RD bit in the EEC register is now set high, a read cycle will be initiated. Setting
the RD bit high will not initiate a read operation if the RDEN bit has not been set. When the read cycle
terminates, the RD bit will be automatically cleared to zero, after which the data can be read from
the EED register. The data will remain in the EED register until another read or write operation is
executed. The application program can poll the RD bit to determine when the data is valid for reading.
Writing Data to the EEPROM
The EEPROM address of the data to be written must first be placed in the EEA register and the data
placed in the EED register. To write data to the EEPROM, the write enable bit, WREN, in the EEC
register must first be set high to enable the write function. After this, the WR bit in the EEC register
must be immediately set high to initiate a write cycle. These two instructions must be executed
consecutively. The global interrupt bit EMI should also first be cleared before implementing any write
operations, and then set again after the write cycle has started. Note that setting the WR bit high will
not initiate a write cycle if the WREN bit has not been set. As the EEPROM write cycle is controlled
using an internal timer whose operation is asynchronous to microcontroller system clock, a certain
time will elapse before the data will have been written into the EEPROM. Detecting when the write
cycle has finished can be implemented either by polling the WR bit in the EEC register or by using
the EEPROM interrupt. When the write cycle terminates, the WR bit will be automatically cleared to
zero by the microcontroller, informing the user that the data has been written to the EEPROM. The
application program can therefore poll the WR bit to determine when the write cycle has ended.
Write Protection
Protection against inadvertent write operation is provided in several ways. After the device is poweredon the Write Enable bit in the control register will be cleared preventing any write operations. Also
at power-on the Bank Pointer, BP, will be reset to zero, which means that Data Memory Bank 0 will
be selected. As the EEPROM control register is located in Bank 1, this adds a further measure of
protection against spurious write operations. During normal program operation, ensuring that the Write
Enable bit in the control register is cleared will safeguard against incorrect write operations.
Rev. 1.40
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BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
EEPROM Interrupt
The EEPROM write interrupt is generated when an EEPROM write cycle has ended. The EEPROM
interrupt must first be enabled by setting the DEE bit in the relevant interrupt register. However as
the EEPROM is contained within a Multi-function Interrupt, the associated multi-function interrupt
enable bit must also be set. When an EEPROM write cycle ends, the DEF request flag and its
associated multi-function interrupt request flag will both be set. If the global, EEPROM and Multifunction interrupts are enabled and the stack is not full, a jump to the associated Multi-function
Interrupt vector will take place. When the interrupt is serviced only the Multi-function interrupt flag
will be automatically reset, the EEPROM interrupt flag must be manually reset by the application
program. More details can be obtained in the Interrupt section.
Programming Considerations
Care must be taken that data is not inadvertently written to the EEPROM. Protection can be
enhanced by ensuring that the Write Enable bit is normally cleared to zero when not writing. Also
the Bank Pointer could be normally cleared to zero as this would inhibit access to Bank 1 where the
EEPROM control register exist. Although certainly not necessary, consideration might be given in the
application program to the checking of the validity of new write data by a simple read back process.
When writing data the WR bit must be set high immediately after the WREN bit has been set high,
to ensure the write cycle executes correctly. The global interrupt bit EMI should also be cleared
before a write cycle is executed and then re-enabled after the write cycle starts.
Programming Examples
Reading Data from the EEPROM – Polling Method
MOV A, EEPROM_ADRES ; user defined address
MOV EEA, A
MOV A, 040H ; setup memory pointer MP1
MOV MP1, A ; MP1 points to EEC register
MOV A, 01H ; setup Bank Pointer
MOV BP, A
SET IAR1.1 ; set RDEN bit, enable read operations
SET IAR1.0 ; start Read Cycle - set RD bit
BACK:
SZ IAR1.0 ; check for read cycle end
JMP BACK
CLR IAR1 ; disable EEPROM read/write
CLR BP
MOV A, EED ; move read data to register
MOV READ_DATA, A
Writing Data to the EEPROM – Polling Method
CLR EMI
MOV A, EEPROM_ADRES ; user defined address
MOV EEA, A
MOV A, EEPROM_DATA ; user defined data
MOV EED, A
MOV A, 040H ; setup memory pointer MP1
MOV MP1, A ; MP1 points to EEC register
MOV A, 01H ; setup Bank Pointer
MOV BP, A
SET IAR1.3 ; set WREN bit, enable write operations
SET IAR1.2 ; Start Write Cycle-set WR bit-executed immediately after set WREN bit
SET EMI
BACK:
SZ IAR1.2 ; check for write cycle end
JMP BACK
CLR IAR1 ; disable EEPROM read/write
CLR BP
Rev. 1.40
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BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Oscillator
Various oscillator options offer the user a wide range of functions according to their various
application requirements. The flexible features of the oscillator functions ensure that the best
optimisation can be achieved in terms of speed and power saving. Oscillator selections and operation
are selected through a combination of configuration options and registers.
Oscillator Overview
In addition to being the source of the main system clock the slow speed oscillators also provide
clock sources for the Watchdog Timer and Time Base. External oscillators requiring some external
components as well as fully integrated internal oscillators, requiring no external components, are
provided to form a wide range of both fast and slow system oscillators. All oscillator options are selected through registers. The higher frequency oscillators provide higher performance but carry
with it the disadvantage of higher power requirements, while the opposite is of course true for the
lower frequency oscillators. With the capability of dynamically switching between fast and slow system clock, the device has the flexibility to optimize the performance/power ratio, a feature especially important in power sensitive portable applications.
Device
All
BS85C20-5
Type
Name
Freq.
Pins
Internal High Speed
HIRC
8,12 or 16MHz
—
Internal Low Speed
LIRC
32kHz
—
External Low Speed
LXT
32.768kHz
OSC1/OSC2
Oscillator Types
System Clock Configurations
There are two methods of generating the system clock, a high speed internal clock source and low
speed internal clock source. The high speed oscillator is an internal 8MHz, 12MHz or 16MHz RC
oscillator while the low speed oscillator is an internal 32kHz RC oscillator. Both oscillators are
fully integrated and do not require external components. 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 allowing the system clock to be dynamically selected.
Internal High Speed RC Oscillator – HIRC
The internal High Speed RC oscillator is a fully integrated system oscillator requiring no external
components. The internal RC oscillator has a power on default frequency of 8 MHz but can be
selected to be either 8MHz, 12MHz or 16MHz using the HIRCS1 and HIRCS0 bits in the CTRL
register. 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.
Rev. 1.40
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March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
CTRL Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
HIRCS1
HIRCS0
—
—
D1
D0
R/W
—
—
R/W
R/W
—
—
R/W
R/W
POR
—
—
0
0
—
—
0
0
"x" unknown
Bit 7~6
unimplemented, read as "0"
Bit 5~4
HIRCS1, HIRCS0: High frequency clock select
00: 8MHz
01: 16MHz
10: 12MHz
11: 8MHz
Bit 3~2 unimplemented, read as "0"
Bit 1~0
D1, D0: These bits must be set to the binary value "00"
External 32.768kHz Crystal Oscillator – LXT (BS85C20-5 only)
For the BS85C20-5, there is an additional external 32.768kHz crystal oscillator that is used as a
clock source for Time Base. This clock source has a fixed frequency of 32.768kHz and requires
a 32.768kHz crystal to be connected between pins OSC1 and OSC2. 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 and stabilise.
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 normally required.
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 inter connecting lines are all
located as close to the MCU as possible.
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
Rev. 1.40
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March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
LXT Oscillator Low Power Function (BS85C20-5 only)
The LXT oscillator can function in one of two modes, the Quick Start Mode and the Low Power
Mode. The mode selection is executed using the LXTLP bit in the TBC register.
LXTLP Bit
LXT Mode
0
Quick Start
1
Low-power
After power on the LXTLP bit, it 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 be
always function normally, the only difference is that it will take more time to start up if it is in the
Low-power mode.
Internal Low Speed RC Oscillator – LIRC
The Internal 32kHz System Oscillator is the low frequency oscillator. It is a fully integrated
RC oscillator with a typical frequency of 32kHz at 5V, requiring no external components for its
implementation. Device trimming during the manufacturing process and the inclusion of internal
frequency compensation circuits are used to ensure that the influence of the power supply voltage,
temperature and process variations on the oscillation frequency are minimised. After power on this
LIRC oscillator will be permanently enabled; there is no provision to disable the oscillator using
register bits.
Operating Modes and System Clocks
Present day applications require that their microcontrollers have high performance but often still
demand that they consume as little power as possible, conflicting requirements that are especially
true in battery powered portable applications. The fast clocks required for high performance will
by their nature increase current consumption and of course vice-versa, lower speed clocks reduce
current consumption. As Holtek has provided these devices with both high and low speed clock
sources and the means to switch between them dynamically, the user can optimise the operation of
their microcontroller to achieve the best performance/power ratio.
System Clocks
The main system clock, can come from either a high frequency, fH, or low frequency, fL, source, and
is selected using the HLCLK bit and CKS2~CKS0 bits in the SMOD register. Both the high and low
speed system clocks are sourced from internal RC oscillators. For BS85C20-5, the Time base 0/1 is sourced from LXT or fSYS/4.
Rev. 1.40
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BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver

System Clock Configurations – BS85B12-3/BS85C20-3

System Clock Configurations – BS85C20-5
Rev. 1.40
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Touch Key Flash MCU with LCD/LED Driver
Control Register
A single register, SMOD, is used for overall control of the internal clocks within the device.
SMOD Register
Rev. 1.40
Bit
7
6
5
4
3
2
1
0
Name
CKS2
CKS1
CKS0
D4
LTO
HTO
IDLEN
HLCLK
R/W
R/W
R/W
R/W
R/W
R
R
R/W
R/W
POR
0
0
0
0
0
0
1
1
Bit 7~5 CKS2~CKS0: The system clock selection when HLCLK is "0"
000: fL (fLIRC)
001: fL (fLIRC)
010: fH/64
011: fH/32
100: fH/16
101: fH/8
110: fH/4
111: fH/2
These three bits are used to select which clock is used as the system clock source.
In addition to the system clock source, which is LIRC, a divided version of the high
speed system oscillator can also be chosen as the system clock source.
Bit 4
Undefined bit
These bits can be read or written by user software program.
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.
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
wake-up has occurred, the flag will change to a high level after 15~16 clock cycles.
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 IDLE1 Mode the CPU will stop running
but the system clock will continue to keep the peripheral functions operational, if
FSYSON bit is high. If FSYSON bit is low, the CPU and the system clock will all stop
in IDLE0 mode. If the bit is low the device will enter the SLEEP Mode when a HALT
instruction is executed.
Bit 0
HLCLK: system clock selection
0: fH/2 ~ fH/64 or fL
1: fH
This bit is used to select if the fH clock or the fH/2 ~ fH/64 or fL clock is used as the
system clock. When the bit is high the fH clock will be selected and if low the fH/2 ~
fH/64 or fL clock will be selected. When system clock switches from the fH clock to the
fL clock and the fH clock will be automatically switched off to conserve power.
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Touch Key Flash MCU with LCD/LED Driver
System Operation Modes
There are five 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 three modes, the SLEEP,
IDLE0 and IDLE1 Mode are used when the microcontroller CPU is switched off to conserve power.
Operation
Mode
Description
CPU
fSYS
fLIRC
fTBC
NORMAL Mode
On
fH~ fH/64
On
On
SLOW Mode
On
fL
On
On
IDLE0 Mode
Off
Off
On
On
IDLE1 Mode
Off
On
On
On
SLEEP Mode
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 the high speed 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 the slow speed
clock source. Running the microcontroller in this mode allows it to run with much lower operating
currents. In the SLOW Mode, the high speed clock is off.
SLEEP Mode
The SLEEP Mode is entered when a HALT instruction is executed and when the IDLEN bit in the
SMOD register is low. In the SLEEP mode the CPU will be stopped however as the fLIRC oscillator
continues to run the Watchdog Timer will continue to operate.
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 WDTC register is low. In the IDLE0 Mode the
system oscillator the system oscillator will be stopped and will therefore be inhibited from driving
the CPU.
IDLE1 Mode
The IDLE1 Mode is entered when a HALT instruction is executed and when the IDLEN bit in the
SMOD register is high and the FSYSON bit in the WDTC 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. In the IDLE1 Mode, the system oscillator will
continue to run, and this system oscillator may be the high speed or low speed system oscillator.
Rev. 1.40
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March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver

Operating Mode Switching
The device can switch between operating modes dynamically allowing the user to select the best
performance/power ratio for the present task in hand. In this way microcontroller operations that
do not require high performance can be executed using slower clocks thus requiring less operating
current and prolonging battery life in portable applications.
In simple terms, Mode Switching between the NORMAL Mode and SLOW Mode is executed
using the HLCLK bit and CKS2~CKS0 bits in the SMOD register while Mode Switching from the
NORMAL/SLOW Modes to the SLEEP/IDLE Modes is executed via the HALT instruction. When
a HALT instruction is executed, whether the device enters the IDLE Mode or the SLEEP Mode is
determined by the condition of the IDLEN bit in the SMOD register and FSYSON in the WDTC
register.
When the HLCLK bit switches to a low level, which implies that clock source is switched from
the high speed clock source, fHIRC, to the clock source, fHIRC/2~fHIRC/64 or fLIRC. If the clock is from
fHIRC, the high speed clock source will stop running to conserve power. When this happens it must be
noted that the fHIRC/16 and fHIRC/64 internal clock sources will also stop running. The accompanying
flowchart shows what happens when the device moves between the various operating modes.
Rev. 1.40
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March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
NORMAL Mode to SLOW Mode Switching
When running in the NORMAL Mode, which uses the high speed system oscillator, and therefore
consumes more power, the system clock can switch to run in the SLOW Mode by set the HLCLK bit
to "0" and set the CKS2~CKS0 bits to "000" or "001" in the SMOD register. This will then use the
low speed system oscillator which will consume less power. Users may decide to do this for certain
operations which do not require high performance and can subsequently reduce power consumption.
The SLOW Mode clock is sourced from the LIRC oscillator.
SLOW Mode to NORMAL Mode Switching
In SLOW Mode the system uses the LIRC low speed system oscillator. To switch back to the
NORMAL Mode, where the high speed system oscillator is used, the HLCLK bit should be set to
"1" or HLCLK bit is "0", but CKS2~CKS0 is set to "010", "011", "100", "101", "110" or "111".
As a certain amount of time will be required for the high frequency clock to stabilise, the status of
the HTO bit is checked. The amount of time required for high speed system oscillator stabilization
depends upon which high speed system oscillator type is used.
Entering the SLEEP Mode
There is only one way for the device to enter the SLEEP Mode and that is to execute the "HALT"
instruction in the application program with the IDLEN bit in SMOD 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 fLIRC clock will be on
• The Data Memory contents and registers will maintain their present condition
• The WDT will be cleared and resume counting
• The I/O ports will maintain their present conditions
• In the status register, the Power Down flag, PDF, will be set and the Watchdog time-out flag, TO,
will be cleared
Rev. 1.40
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March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Entering the IDLE0 Mode
There is only one way for the device to enter the IDLE0 Mode and that is to execute the "HALT"
instruction in the application program with the IDLEN bit in SMOD register equal to "1" and the
FSYSON bit in WDTC register equal to "0". When this instruction is executed under the conditions
described above, the following will occur:
• The system clock will be stopped and the application program will stop at the "HALT" instruction,
but the Time Base clock and fLIRC clock will be on
• The Data Memory contents and registers will maintain their present condition
• The WDT will be cleared and resume counting
• The I/O ports will maintain their present conditions
• In the status register, the Power Down flag, PDF, will be set and the Watchdog time-out flag, TO,
will be cleared
Entering the IDLE1 Mode
There is only one way for the device to enter the IDLE1 Mode and that is to execute the "HALT"
instruction in the application program with the IDLEN bit in SMOD register equal to "1" and the
FSYSON bit in WDTC register equal to "1". When this instruction is executed under the with
conditions described above, the following will occur:
• The system clock and fLIRC clock will be on and the application program will stop at the "HALT"
instruction
• The Data Memory contents and registers will maintain their present condition
• The WDT will be cleared and resume counting
• The I/O ports will maintain their present conditions
• In the status register, the Power Down flag, PDF, will be set and the Watchdog time-out flag, TO,
will be cleared
Standby Current Considerations
As the main reason for entering the SLEEP or IDLE Mode is to keep the current consumption of the
device to as low a value as possible, perhaps only in the order of several micro-amps except in the
IDLE1 Mode, there are other considerations which must also be taken into account by the circuit
designer if the power consumption is to be minimised. Special attention must be made to the I/O pins
on the device. All high-impedance input pins must be connected to either a fixed high or low level as
any floating input pins could create internal oscillations and result in increased current consumption.
This also applies to devices which have different package types, as there may be unbonbed pins.
These must either be setup as outputs or if setup as inputs must have pull-high resistors connected.
Care must also be taken with the loads, which are connected to I/O pins, which are setup as outputs.
These should be placed in a condition in which minimum current is drawn or connected only to
external circuits that do not draw current, such as other CMOS inputs.
In the IDLE1 Mode the system oscillator is on, if the system oscillator is from the high speed system
oscillator, the additional standby current will also be perhaps in the order of several hundred microamps.
Rev. 1.40
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BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Wake-up
After the system enters the SLEEP or IDLE Mode, it can be woken up from one of various sources
listed as follows:
• An external reset
• An external falling edge on Port A
• A system interrupt
• A WDT overflow
If the system is woken up by an external reset, the device will experience a full system reset,
however, if the device is woken up by a WDT overflow, a Watchdog Timer reset will be initiated.
Although both of these wake-up methods will initiate a reset operation, the actual source of the
wake-up can be determined by examining the TO and PDF flags. The PDF flag is cleared by a
system power-up or executing the clear Watchdog Timer instructions and is set when executing
the "HALT" instruction. The TO flag is set if a WDT time-out occurs, and causes a wake-up that only
resets the Program Counter and Stack Pointer, the other flags remain in their original status.
Each pin on Port A can be setup using the PAWU register to permit a negative transition on the pin
to wake-up the system. When a Port A pin wake-up occurs, the program will resume execution at
the instruction following the "HALT" instruction. If the system is woken up by an interrupt, then
two possible situations may occur. The first is where the related interrupt is disabled or the interrupt
is enabled but the stack is full, in which case the program will resume execution at the instruction
following the "HALT" instruction. In this situation, the interrupt which woke-up the device will not be
immediately serviced, but will rather be serviced later when the related interrupt is finally enabled or
when a stack level becomes free. The other situation is where the related interrupt is enabled and the
stack is not full, in which case the regular interrupt response takes place. If an interrupt request flag is
set high before entering the SLEEP or IDLE Mode, the wake-up function of the related interrupt will
be disabled.
System
Oscillator
Wake-up Time
(SLEEP Mode)
Wake-up Time
(IDLE0 Mode)
Wake-up Time
(IDLE1 Mode)
HIRC
15~16 HIRC cycles
1~2 HIRC cycles
LIRC
1~2 LIRC cycles
1~2 LIRC cycles
Wake-Up Times
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 SLEEP Mode the HIRC oscillator needs to start-up from an off state.
• If the device is woken up from the SLEEP Mode to the NORMAL Mode, the high speed system
oscillator needs an SST period. The device will execute the first instruction after HTO is high.
Rev. 1.40
51
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Watchdog Timer
The Watchdog Timer is provided to prevent program malfunctions or sequences from jumping to
unknown locations, due to certain uncontrollable external events such as electrical noise.
Watchdog Timer Clock Source
The Watchdog Timer clock source is provided by the internal low speed oscillator, fLIRC. The
Watchdog Timer source clock is then subdivided by a ratio of 28 to 215 to give longer timeouts,
the actual value being chosen using the WS2~WS0 bits in the WDTC register. The LIRC internal
oscillator has an approximate period of 32kHz at a supply voltage of 5V.
However, it should be noted that this specified internal clock period can vary with VDD, temperature
and process variations.
Watchdog Timer Control Register
A single register, WDTC, controls the required timeout period.
WDTC Register
Rev. 1.40
Bit
7
6
5
4
3
2
1
0
Name
FSYSON
WS2
WS1
WS0
D3
D2
D1
D0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
1
1
1
1
0
1
0
Bit 7 FSYSON: fSYS control in IDLE Mode
0: disable
1: enable
Bit 6~4
WS2, WS1, WS0 : WDT time-out period selection
000: 256/fLIRC
001: 512/fLIRC
010: 1024/fLIRC
011: 2048/fLIRC
100: 4096/fLIRC
101: 8192/fLIRC
110: 16384/fLIRC
111: 32768/fLIRC
These three bits determine the division ratio of the Watchdog Timer source clock,
which in turn determines the timeout period.
Bit 3~0
Undefined bit
These bits can be read or written by user software program.
52
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Watchdog Timer Operation
In these devices the Watchdog Timer supplied by the fLIRC oscillator and is therefore always on. The
Watchdog Timer operates by providing a device reset when its timer overflows. This means that in
the application program and during normal operation the user has to strategically clear the Watchdog
Timer before it overflows to prevent the Watchdog Timer from executing a reset. This is done using
the clear watchdog instructions. If the program malfunctions for whatever reason, jumps to
an unkown location, or enters an endless loop, these clear instructions will not be executed in the
correct manner, in which case the Watchdog Timer will overflow and reset the device.
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 an external hardware reset, the second is using the Watchdog Timer software clear
instructions and the third is via a HALT instruction. The Watchdog Timer is cleared using a single
CLR WDT instruction.
The maximum time out period is when the 215 division ratio is selected. As an example, with the
LIRC oscillator as its source clock, this will give a maximum watchdog period of around 1 second
for the 215 division ratio, and a minimum timeout of 7.8ms for the 28 division ration.

Watchdog Timer
Rev. 1.40
53
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Reset and Initialisation
A reset function is a fundamental part of any microcontroller ensuring that the device can be set
to some predetermined condition irrespective of outside parameters. The most important reset
condition is after power is first applied to the microcontroller. In this case, internal circuitry will
ensure that the microcontroller, after a short delay, will be in a well defined state and ready to
execute the first program instruction. After this power-on reset, certain important internal registers
will be set to defined states before the program commences. One of these registers is the Program
Counter, which will be reset to zero forcing the microcontroller to begin program execution from the
lowest Program Memory address.
Another type of reset is when the Watchdog Timer overflows and resets the microcontroller. All
types of reset operations result in different register conditions being setup. Another reset exists in the
form of a Low Voltage Reset, LVR, where a full reset, is implemented in situations where the power
supply voltage falls below a certain threshold.
Reset Functions
There are several ways in which a microcontroller reset can occur, through events occurring both
internally and externally:
Power-on Reset
The most fundamental and unavoidable reset is the one that occurs after power is first applied to
the microcontroller. As well as ensuring that the Program Memory begins execution from the first
memory address, a power-on reset also ensures that certain other registers are preset to known
conditions. All the I/O port and port control registers will power up in a high condition ensuring that
all pins will be first set to inputs.
Note: tRSTD is power-on delay, typical time=100ms
Power-On Reset Timing Chart
Low Voltage Reset – LVR
If the supply voltage of the device drops to within a range of 0.9V~VLVR such as might occur when
changing the battery, the LVR will automatically reset the device internally. The LVR includes the
following specifications: For a valid LVR signal, a low voltage, i.e., a voltage in the range between
0.9V~VLVR must exist for greater than the value tLVR specified in the A.C. characteristics. If the low voltage
state does not exceed tLVR, the LVR will ignore it and will not perform a reset function. One of a range
of specified voltage values for VLVR can be selected using configuration options. The LVR function is
permanently on in these devices.
Note: tRSTD is power-on delay, typical time=100ms
Low Voltage Reset Timing Chart
Rev. 1.40
54
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Watchdog Time-out Reset during Normal Operation
The Watchdog time-out Reset during normal operation is the same as a hardware power-on reset
except that the Watchdog time-out flag TO will be set to "1".
Note: tRSTD is power-on delay, typical time=100ms
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.
Note: The tSST is 15~16 clock cycles if the system clock source is provided by HIRC. The tSST is 1~2
clock for LIRC.
WDT Time-out Reset during SLEEP or IDLE Timing Chart
Reset Initial Conditions
The different types of reset described affect the reset flags in different ways. These flags, known
as PDF and TO are located in the status register and are controlled by various microcontroller
operations, such as the SLEEP or IDLE Mode function or Watchdog Timer. The reset flags are
shown in the table:
TO
PDF
RESET Conditions
0
0
Power-on reset
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
Rev. 1.40
Condition After RESET
Program Counter
Reset to zero
Interrupts
All interrupts will be disabled
WDT
Clear after reset, WDT begins counting
Timer Modules
Timer Counter will be turned off
Input/Output Ports
I/O ports will be setup as inputs
Stack Pointer
Stack Pointer will point to the top of the stack
55
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
The different kinds of resets all affect the internal registers of the microcontroller in different ways.
To ensure reliable continuation of normal program execution after a reset occurs, it is important to
know what condition the microcontroller is in after a particular reset occurs. The following table
describes how each type of reset affects each of the microcontroller internal registers. Note that where
more than one package type exists the table will reflect the situation for the larger package type.
BS85B12-3
/BS85B20-5
BS85B20-3
Power-on
Reset
MP0
•
•
xxxx xxxx
uuuu uuuu
uuuu uuuu
MP1
•
•
xxxx xxxx
uuuu uuuu
uuuu uuuu
uuuu uuuu
BP
•
---- ---0
---- ---0
---- ---0
---- ---u
---- --00
---- --00
---- --00
---- --uu
Register
BP
•
LVR Reset
Time-out
(Normal Operation)
Time-out
(IDLE or SLEEP)
uuuu uuuu
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
•
•
-xxx xxxx
-uuu uuuu
-uuu uuuu
-uuu uuuu
TBHP
•
---- -uuu
---- -xxx
---- -uuu
---- -uuu
•
---- xxxx
---- uuuu
---- uuuu
---- uuuu
•
•
--00 xxxx
--uu uuuu
--1u uuuu
--11 uuuu
•
•
0000 0011
0000 0011
0000 0011
uuuu uuuu
TBHP
SMOD
LVDC
•
•
- -0 0 - 0 0 0
- -0 0 - 0 0 0
- -0 0 - 0 0 0
--uu -uuu
INTEG
•
•
---- 0000
---- 0000
---- 0000
---- uuuu
WDTC
•
•
0111 1010
0111 1010
0111 1010
uuuu uuuu
TBC
•
•
0011 0111
0011 0111
0011 0111
uuuu uuuu
•
•
-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
INTC3
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
MFI0
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
MFI1
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
MFI2
•
•
-000 -000
-000 -000
-000 -000
-uuu -uuu
MFI3
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
PAWU
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
PAPU
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
PA
•
•
1111 1111
1111 1111
1111 1111
uuuu uuuu
PAC
•
•
PBPU
•
PBPU
PB
•
•
PB
PBC
•
•
PBC
•
1111 1111
1111 1111
1111 1111
uuuu uuuu
--00 0000
--00 0000
--00 0000
--uu uuuu
0000 0000
0000 0000
0000 0000
uuuu uuuu
--11 1111
--11 1111
--11 1111
--uu uuuu
1111 1111
1111 1111
1111 1111
uuuu uuuu
--11 1111
--11 1111
--11 1111
--uu uuuu
1111 1111
1111 1111
1111 1111
uuuu uuuu
PCPU
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
PC
•
•
1111 1111
1111 1111
1111 1111
uuuu uuuu
PCC
•
•
1111 1111
1111 1111
1111 1111
uuuu uuuu
PDPU
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
PD
•
1111 1111
1111 1111
1111 1111
uuuu uuuu
PDC
•
1111 1111
1111 1111
1111 1111
uuuu uuuu
Rev. 1.40
56
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
/BS85B20-5
BS85B20-3
PEPU
•
--00 0000
--00 0000
--00 0000
--uu uuuu
PE
•
--11 1111
--11 1111
--11 1111
--uu uuuu
PEC
•
--11 1111
--11 1111
--11 1111
--uu uuuu
BS85B12-3
Power-on
Reset
Register
LVR Reset
Time-out
(Normal Operation)
Time-out
(IDLE or SLEEP)
SLCDC0
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
SLCDC1
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
SLCDC2
•
--00 0000
--00 0000
--00 0000
--uu uuuu
uuuu uuuu
SLCDC2
•
0000 0000
0000 0000
0000 0000
SLCDC3
•
0-00 0000
0-00 0000
0-00 0000
u-uu uuuu
--00 0000
--00 0000
--00 0000
--uu uuuu
SLEDC0
•
SLEDC0
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
SLEDC2
•
--00 0000
--00 0000
--00 0000
--uu uuuu
MFI4
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
MFI5
•
--00 --00
--00 --00
--00 --00
--uu --uu
SLEDC1
•
I2CTOC
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
SIMC0
•
•
1110 000-
1110 000-
1110 000-
uuuu uuu-
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
TM0C0
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM0C1
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM0DL
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM0DH
•
•
---- --00
---- --00
---- --00
---- --uu
TM0AL
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM0AH
•
•
---- --00
---- --00
---- --00
---- --uu
EEA
•
00 0000
00 0000
00 0000
uu uuuu
EEA
•
000 0000
000 0000
000 0000
uuu uuuu
EED
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TMPC0
•
•
1001 01
1001 01
1001 01
uuuu uu
•
---- --01
---- --01
---- --01
---- --uu
-0-0 -0-0
-0-0 -0-0
-0-0 -0-0
-u-u -u-u
TMPC1
PRM0
•
PRM0
PRM1
•
•
PRM1
PRM2
•
0000 0000
0000 0000
uuuu uuuu
0000 -0-0
0000 -0-0
uuuu -u-u
0000 0000
0000 0000
0000 0000
uuuu uuuu
0000 --00
0000 --00
0000 --00
uuuu --uu
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
•
PRM2
0000 0000
0000 -0-0
TM1C0
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM1C1
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM1C2
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM1DL
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM1DH
•
•
---- --00
---- --00
---- --00
---- --uu
TM1AL
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM1AH
•
•
---- --00
---- --00
---- --00
---- --uu
TM1BL
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
Rev. 1.40
57
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
BS85B12-3
/BS85B20-5
BS85B20-3
•
•
----
- -0 0
---- --00
---- --00
---- --uu
TM2C0
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM2C1
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM2DL
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM2DH
•
---- --00
---- --00
---- --00
---- --uu
TM2AL
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TM2AH
•
---- --00
---- --00
---- --00
---- --uu
Register
TM1BH
Power-on
Reset
LVR Reset
Time-out
(Normal Operation)
Time-out
(IDLE or SLEEP)
CTRL
•
•
--00 --00
--00 --00
--00 --00
--uu --uu
TKM016DH
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM016DL
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM0C0
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM0C1
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM0C2
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM0C3
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM116DH
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM116DL
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM1C0
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM1C1
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM1C2
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM1C3
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM216DH
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM216DL
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM2C0
TKM2C1
•
•
0000 ----
0000 ----
0000 ----
uuuu ----
TKM2C2
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM2C3
•
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM316DH
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM316DL
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM3C0
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM3C1
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM3C2
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM3C3
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM416DH
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM416DL
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM4C0
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM4C1
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM4C2
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
TKM4C3
•
0000 0000
0000 0000
0000 0000
uuuu uuuu
•
---- 0000
---- 0000
---- 0000
---- uuuu
EEC
•
Note: "u" stands for unchanged
"x" stands for unknown
"-" stands for unimplemented
Rev. 1.40
58
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Input/Output Ports
Holtek microcontrollers offer considerable flexibility on their I/O ports. With the input or output
designation of every pin fully under user program control, pull-high selections for all ports and
wake-up selections on certain pins, the user is provided with an I/O structure to meet the needs of a
wide range of application possibilities.
The device provides bidirectional input/output lines labeled with port names PA~PE. These I/O
ports are mapped to the RAM Data Memory with specific addresses as shown in the Special Purpose
Data Memory table. All of these I/O ports can be used for input and output operations. For input
operation, these ports are non-latching, which means the inputs must be ready at the T2 rising edge
of instruction "MOV A,[m]", where m denotes the port address. For output operation, all the data is
latched and remains unchanged until the output latch is rewritten.
I/O Register List
BS85B12-3
Bit
Register
Name
7
6
5
4
3
2
1
0
PAWU
D7
D6
D5
D4
D3
D2
D1
D0
PAPU
D7
D6
D5
D4
D3
D2
D1
D0
PA
D7
D6
D5
D4
D3
D2
D1
D0
PAC
D7
D6
D5
D4
D3
D2
D1
D0
PBPU
—
—
D5
D4
D3
D2
D1
D0
PB
—
—
D5
D4
D3
D2
D1
D0
PBC
—
—
D5
D4
D3
D2
D1
D0
PCPU
D7
D6
D5
D4
D3
D2
D1
D0
PC
D7
D6
D5
D4
D3
D2
D1
D0
PCC
D7
D6
D5
D4
D3
D2
D1
D0
BS85C20-3/BS85C20-5
Rev. 1.40
Bit
Register
Name
7
6
5
4
3
2
1
0
PAWU
D7
D6
D5
D4
D3
D2
D1
D0
PAPU
D7
D6
D5
D4
D3
D2
D1
D0
PA
D7
D6
D5
D4
D3
D2
D1
D0
PAC
D7
D6
D5
D4
D3
D2
D1
D0
PBPU
D7
D6
D5
D4
D3
D2
D1
D0
PB
D7
D6
D5
D4
D3
D2
D1
D0
PBC
D7
D6
D5
D4
D3
D2
D1
D0
PCPU
D7
D6
D5
D4
D3
D2
D1
D0
PC
D7
D6
D5
D4
D3
D2
D1
D0
PCC
D7
D6
D5
D4
D3
D2
D1
D0
PDPU
D7
D6
D5
D4
D3
D2
D1
D0
PD
D7
D6
D5
D4
D3
D2
D1
D0
PDC
D7
D6
D5
D4
D3
D2
D1
D0
PEPU
—
—
D5
D4
D3
D2
D1
D0
PE
—
—
D5
D4
D3
D2
D1
D0
PEC
—
—
D5
D4
D3
D2
D1
D0
59
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Pull-high Resistors
Many product applications require pull-high resistors for their switch inputs usually requiring the
use of an external resistor. To eliminate the need for these external resistors, all I/O pins, when
configured as an input have the capability of being connected to an internal pull-high resistor. These
pull-high resistors are selected using the register PAPU~PEPU, and are implemented using weak
PMOS transistors.
BS85B12-3: PAPU, PCPU Registers
BS85C20-3/BS85C20-5: PAPU, PBPU, PCPU, PDPU Registers
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
PxPU: Port bit 7~bit 0 Pull-High control
0: disable
1: enable
BS85B12-3: PBPU Registers
BS85C20-3/BS85C20-5: PEPU Registers
Bit
7
6
5
4
3
2
1
0
Name
—
—
D5
D4
D3
D2
D1
D0
R/W
—
—
R/W
R/W
R/W
R/W
R/W
R/W
POR
—
—
0
0
0
0
0
0
Bit 7~4
unimplemented, read as "0"
Bit 3~0
PxPU: Port bit 5~bit 0 Pull-High control
0: disable
1: enable
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
Rev. 1.40
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 7~5
unimplemented, read as "0"
Bit 4~0
PAWU: Port A bit 7~bit 0 wake-up control
0: disable
1: enable
60
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
I/O Port Control Register
The I/O port has its own control register known as PAC~PEC, 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 port is directly mapped to a bit in its
associated port control register. For the I/O pin to function as an input, the corresponding bit of the
control register must be written as a "1". This will then allow the logic state of the input pin to be
directly read by instructions. When the corresponding bit of the control register is written as a "0",
the I/O pin will be setup as a CMOS output. If the pin is currently setup as an output, instructions
can still be used to read the output register. However, it should be noted that the program will in fact
only read the status of the output data latch and not the actual logic status of the output pin.
BS85B12-3: PAC, PCC Registers
BS85C20-3/BS85C20-5: PAC, PBC, PCC, PDC Registers
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
1
1
1
1
1
1
1
1
2
1
0
Bit 7~0
PxC: I/O Port bit 7 ~ bit 0 input/output control
0: output
1: input
BS85B12-3: PBC Registers
BS85C20-3/BS85C20-5: PEC Registers
Bit
7
6
5
4
3
Name
—
—
D5
D4
D3
D2
D1
D0
R/W
—
—
R/W
R/W
R/W
R/W
R/W
R/W
POR
—
—
0
0
1
1
1
1
Bit 7~4
unimplemented, read as "0"
Bit 3~0
PxC: Port bit 5~bit 0 input/output control
0: output
1: input
Pin Re-mapping 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 are a
series of PRM0, PRM1 and PRM2 registers to establish certain pin functions.
Pin-remapping Registers
The limited number of supplied pins in a package can impose restrictions on the amount of functions
a certain device can contain. However by allowing the same pins to share several different functions
and providing a means of function selection, a wide range of different functions can be incorporated
into even relatively small package sizes. The device includes PRM0, PRM1, PRM2 registers which
can select the functions of certain pins.
Rev. 1.40
61
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Pin-remapping Register List
• BS85B12-3
Bit
Register
Name
7
6
5
4
3
2
1
0
PRM0
—
SCSPS0
—
SDIPS0
—
SCKPS0
—
SDOPS0
PRM1
INT1PS
INT0PS
TCK1PS
TCK0PS
—
PINTS0
—
PCKPS0
TP1B2PS TP1B1PS TP1B0PS TP1APS
—
—
TP01PS
TP00PS
4
3
2
1
0
PRM2
• BS85C20-3/BS85C20-5
Bit
Register
Name
7
6
PRM0
SCSPS1
SCSPS0
SDIPS1
SDIPS0
SCKPS1
SCKPS0
SDOPS1 SDOPS0
PRM1
INT1PS
INT0PS
TCK1PS
TCK0PS
PINTS1
PINTS0
PCKPS1
PCKPS0
TP1B2PS TP1B1PS TP1B0PS TP1APS
TP21PS
TP20PS
TP01PS
TP00PS
PRM2
SLCDC3
TCK2PS
—
5
SEG21EN SEG20EN SEG19EN SEG18EN SEG17EN SEG16EN
PRM0 Register – BS85B12-3
Rev. 1.40
Bit
7
6
5
4
3
2
1
0
Name
—
SCSPS0
—
SDIPS0
—
SCKPS0
—
SDOPS0
R/W
—
R/W
—
R/W
—
R/W
—
R/W
POR
—
0
—
0
—
0
—
0
Bit 7
unimplemented, read as "0"
Bit 6
SCSPS0: SCS pin remapping control
0: SCS on PA3
1: SCS on PC3
Bit 5
unimplemented, read as "0"
Bit 4
SDIPS0: SDI/SDA pin remapping control
0: SDI/SDA on PA0
1: SDI/SDA on PC2
Bit 3
unimplemented, read as "0"
Bit 2
SCKPS0: SCK/SCL pin remapping control
0: SCK/SCL on PA2
1: SCK/SCL on PC1
Bit 1
unimplemented, read as "0"
Bit 0
SDOPS0: SDO pin remapping control
0: SDO on PA7
1: SDO on PC0
62
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
PRM0 Register – BS85C20-3/BS85C20-5
Bit
7
6
5
4
3
2
Name
SCSPS1
SCSPS0
SDIPS1
SDIPS0
SCKPS1
SCKPS0
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
SCSPS1~SCSPS0: SCS pin remapping control
00: SCS on PA3
01: SCS on PC3
10: SCS on PE2
11: undefined
Bit 5~4
SDIPS1~SDIPS0: SDI/SDA pin remapping control
00: SDI/SDA on PA0
01: SDI/SDA on PC2
10: SDI/SDA on PE4
11: undefined
Bit 3~2
SCKPS1~SCKPS0: SCK/SCL pin remapping control
00: SCK/SCL on PA2
01: SCK/SCL on PC1
10: SCK/SCL on PE3
11: undefined
Bit 1~0
SDOPS1~SDOPS0: SDO pin remapping control
00: SDO on PA7
01: SDO on PC0
10: SDO on PE5
11: undefined
1
0
SDOPS1 SDOPS0
PRM1 Register – BS85B12-3
Rev. 1.40
Bit
7
6
5
4
3
2
1
0
Name
INT1PS
INT0PS
TCK1PS
TCK0PS
—
PINTS0
—
PCKPS0
R/W
R/W
R/W
R/W
R/W
—
R/W
—
R/W
POR
0
0
0
0
—
0
—
0
Bit 7
INT1PS: INT1 pin remapping control
0: INT1 on PA1
1: INT1 on PC5
Bit 6
INT0PS: INT0 pin remapping control
0: INT0 on PA4
1: INT0 on PC4
Bit 5
TCK1PS: TCK1 pin remapping control
0: TCK1 on PA1
1: TCK1 on PC5
Bit 4
TCK0PS: TCK0 pin remapping control
0: TCK0 on PA4
1: TCK0 on PC4
Bit 3
unimplemented, read as "0"
Bit 2
PINTS0: PINT pin remapping control
0: PINT on PB5
1: PINT on PC7
Bit 1
unimplemented, read as "0"
Bit 0
PCKPS0: PCK pin remapping control
0: PCK on PB4
1: PCK on PC6
63
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
PRM1 Register – BS85C20-3/BS85C20-5
Bit
7
6
5
4
3
2
1
0
Name
INT1PS
INT0PS
TCK1PS
TCK0PS
PINTS1
PINTS0
PCKPS1
PCKPS0
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
INT1PS: INT1 pin remapping control
0: INT1 on PA1
1: INT1 on PC5
Bit 6
INT0PS: INT0 pin remapping control
0: INT0 on PA4
1: INT0 on PC4
Bit 5
TCK1PS: TCK1 pin remapping control
0: TCK1 on PA1
1: TCK1 on PC5
Bit 4
TCK0PS: TCK0 pin remapping control
0: TCK0 on PA4
1: TCK0 on PC4
Bit 3~2
PINTS1~PINTS0: PINT pin remapping control
00: PINT on PB5
01: PINT on PC7
10: PINT on PE0
11: undefined
Bit 1~0
PCKPS1~PCKPS0: PCK pin remapping control
00: PCK on PB4
01: PCK on PC6
10: PCK on PE1
11: undefined
PRM2 Register – BS85B12-3
Bit
Name
Rev. 1.40
7
6
5
4
TP1B2PS TP1B1PS TP1B0PS TP1APS
3
2
1
0
—
—
TP01PS
TP00PS
R/W
R/W
R/W
R/W
R/W
—
—
R/W
R/W
POR
0
0
0
0
—
—
0
0
Bit 7
TP1B2PS: TP1B_2 pin remapping cControl
0: TP1B_2 on PB4
1: TP1B_2 on PC4
Bit 6
TP1B1PS: TP1B_1 pin remapping control
0: TP1B_1 on PB3
1: TP1B_1 on PC3
Bit 5
TP1B0PS: TP1B_0 pin remapping control
0: TP1B_0 on PB2
1: TP1B_0 on PC2
Bit 4
TP1APS: TP1A pin remapping control
0: TP1A on PB5
1: TP1A on PC5
Bit 3~2
unimplemented, read as "0"
Bit 1
TP01PS: TP0_1 Pin Remapping Control
0: TP0_1 on PB1
1: TP0_1 on PC1
Bit 0
TP00PS: TP0_0 Pin Remapping Control
0: TP0_0 on PB0
1: TP0_0 on PC0
64
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
PRM2 Register – BS85C20-3/BS85C20-5
Bit
Name
7
6
5
4
TP1B2PS TP1B1PS TP1B0PS TP1APS
3
2
1
0
TP21PS
TP20PS
TP01PS
TP00PS
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
TP1B2PS: TP1B_2 pin remapping control
0: TP1B_2 on PB4
1: TP1B_2 on PC4
Bit 6
TP1B1PS: TP1B_1 pin remapping control
0: TP1B_1 on PB3
1: TP1B_1 on PC3
Bit 5
TP1B0PS: TP1B_0 pin remapping control
0: TP1B_0 on PB2
1: TP1B_0 on PC2
Bit 4
TP1APS: TP1A pin remapping coontrol
0: TP1A on PB5
1: TP1A on PC5
Bit 3
TP21PS: TP2_1 pin remapping coontrol
0: TP2_1 on PB2
1: TP2_1 on PE2
Bit 2
TP20PS: TP2_0 pin remapping coontrol
0: TP2_0 on PB1
1: TP2_0 on PE1
Bit 1
TP01PS: TP0_1 pin remapping coontrol
0: TP0_1 on PB1
1: TP0_1 on PC1
Bit 0
TP00PS: TP0_0 pin remapping coontrol
0: TP0_0 on PB0
1: TP0_0 on PC0
SLCDC3 Register – BS85C20-3/BS85C20-5
Rev. 1.40
Bit
7
6
Name
TCK2PS
—
5
4
3
R/W
R/W
—
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
—
0
0
0
0
0
0
SEG21EN SEG20EN SEG19EN SEG18EN SEG17EN SEG16EN
Bit 7
TCK2PS: TCK2 pin remapping control
0: TCK2 on PC6
1: TCK2 on PD0
Bit 6
unimplemented, read as "0"
Bit 5~0
described elsewhere
65
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
I/O Pin Structures
The accompanying diagrams illustrate the internal structures of some generic I/O pin types. As
the exact logical construction of the I/O pin will differ from these drawings, they are supplied as a
guide only to assist with the functional understanding of the I/O pins. The wide range of pin-shared
structures does not permit all types to be shown.

Generic Input/Output Structure
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 register 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 pull-high
selections have been chosen. If the port control register, PAC~PEC, is then programmed to setup
some pins as outputs, these output pins will have an initial high output value unless the associated
port data register, PA~PE, is first programmed. Selecting which pins are inputs and which are
outputs can be achieved byte-wide by loading the correct values into the appropriate port control
register or by programming individual bits in the port control register using the "SET [m].i" and
"CLR [m].i" instructions. Note that when using these bit control instructions, a read-modify-write
operation takes place. The microcontroller must first read in the data on the entire port, modify it to
the required new bit values and then rewrite this data back to the output ports.
Port A has the additional capability of providing wake-up functions. When the device is in the
SLEEP or IDLE Mode, various methods are available to wake the device up. One of these is a high
to low transition of any of the Port A pins. Single or multiple pins on Port A can be setup to have this
function.
Rev. 1.40
66
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Timer Modules – TM
One of the most fundamental functions in any microcontroller device is the ability to control and
measure time. To implement time related functions each device includes several Timer Modules,
abbreviated to the name TM. The TMs are multi-purpose timing units and serve to provide
operations such as Timer/Counter, Input Capture, Compare Match Output and Single Pulse Output
as well as being the functional unit for the generation of PWM signals. Each of the TMs has either
two or three individual interrupts. The addition of input and output pins for each TM ensures that
users are provided with timing units with a wide and flexible range of features.
The common features of the different TM types are described here with more detailed information
provided in the individual Compact, Standard and Enhanced TM sections.
Introduction
The devices contain from two to three TMs depending upon which device is selected with each
TM having a reference name of TM0, TM1 and TM2. Each individual TM can be categorised as
a certain type, namely Compact Type TM, Standard Type TM or Enhanced 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 Enhanced TMs will be described in this section, 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.
Function
CTM
STM
ETM
Timer/Counter
√
√
√
I/P Capture
—
√
√
Compare Match Output
√
√
√
PWM Channels
1
1
2
Single Pulse Output
—
1
2
Edge
Edge
Edge & Centre
Duty or Period
Duty or Period
Duty or Period
PWM Alignment
PWM Adjustment Period & Duty
TM Function Summary
Each device in the series contains a specific number of either Compact Type, Standard Type and
Enhanced Type TM units which are shown in the table together with their individual reference name,
TM0~TM2.
Device
TM0
TM1
TM2
BS85B12-3
10-bit CTM
10-bit ETM
—
BS85C20-3
/BS85C20-5
10-bit CTM
10-bit ETM
10-bit STM
TM Name/Type Reference
TM Operation
The three different types of TM offer a diverse range of functions, from simple timing operations
to PWM signal generation. The key to understanding how the TM operates is to see it in terms of
a free running counter whose value is then compared with the value of pre-programmed internal
comparators. When the free running counter has the same value as the pre-programmed comparator,
known as a compare match situation, a TM interrupt signal will be generated which can clear the
counter and perhaps also change the condition of the TM output pin. The internal TM counter is
driven by a user selectable clock source, which can be an internal clock or an external pin.
Rev. 1.40
67
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
TM Clock Source
The clock source which drives the main counter in each TM can originate from various sources.
The selection of the required clock source is implemented using the TnCK2~TnCK0 bits in the TM
control registers. The clock source can be a ratio of either the system clock fSYS or the internal high
clock fH, the fTBC clock source or the external TCKn pin. Note that setting these bits to the value 101
will select a reserved clock input, in effect disconnecting the TM clock source. The TCKn pin clock
source is used to allow an external signal to drive the TM as an external clock source or for event
counting.
TM Interrupts
The Compact and Standard type TMs each have two internal interrupts, one for each of the internal
comparator A or comparator P, which generate a TM interrupt when a compare match condition
occurs. As the Enhanced type TM has three internal comparators and comparator A or comparator
B or comparator P compare match functions, it consequently has three internal interrupts. When a
TM interrupt is generated it can be used to clear the counter and also to change the state of the TM
output pin.
TM External Pins
Each of the TMs, irrespective of what type, has one TM input pin, with the label TCKn. The TM
input pin, is essentially a clock source for the TM and is selected using the TnCK2~TnCK0 bits in
the TMnC0 register. This external TM input pin allows an external clock source to drive the internal
TM. This external TM input pin is shared with other functions but will be connected to the internal
TM if selected using the TnCK2~TnCK0 bits. The TM input pin can be chosen to have either a
rising or falling active edge.
The TMs each have one or more output pins with the label TPn. When the TM is in the Compare
Match Output Mode, these pins can be controlled by the TM to switch to a high or low level or to
toggle when a compare match situation occurs. The external TPn output pin is also the pin where
the TM generates the PWM output waveform. As the TM output pins are pin-shared with other
function, the TM output function must first be setup using registers. A single bit in one of the
registers determines if its associated pin is to be used as an external TM output pin or if it is to have
another function. The number of output pins for each TM type and device is different, the details are
provided in the accompanying table.
All TM output pin names have an "_n" suffix. Pin names that include a "_1" or "_2" suffix indicate
that they are from a TM with multiple output pins. This allows the TM to generate a complimentary
output pair, selected using the I/O register data bits.
Device
CTM
STM
ETM
Registers
TMPC0
TMPC0, TMPC1
BS85B12-3
TP0_0, TP0_1
—
TP1A, TP1B_0,
TP1B_1, TP1B_2
BS85C20-3
/BS85C20-5
TP0_0, TP0_1
TP2_0, TP2_1
TP1A, TP1B_0,
TP1B_1, TP1B_2
TM Output Pins
Rev. 1.40
68
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
TM Input/Output Pin Control Registers
Selecting to have a TM input/output or whether to retain its other shared function, is implemented
using one or two registers, with a single bit in each 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 retain its original other function.
Registers
Device
TMPC0
TMPC0
Bit
7
6
5
4
3
2
1
0
All
T1ACP0
T1BCP2
T1BCP1
T1BCP0
—
—
T0CP1
T0CP0
BS85C20-3
/BS85C20-5
—
—
—
—
—
—
T2CP1
T2CP0
TM Input/Output Pin Control Registers List
TMPC0 Register – All devices
Bit
7
6
5
4
3
2
1
0
Name
T1ACP0
T1BCP2
T1BCP1
T1BCP0
—
—
T0CP1
T0CP0
R/W
R/W
R/W
R/W
R/W
—
—
R/W
R/W
POR
1
0
0
1
—
—
0
1
Bit 7
T1ACP0: TP1A pin Control
0: disable
1: enable
Bit 6
T1BCP2: TP1B_2 pin Control
0: disable
1: enable
Bit 5
T1BCP1: TP1B_1 pin Control
0: disable
1: enable
Bit 4
T1BCP0: TP1B_0 pin Control
0: disable
1: enable
Bit 3~2
Unimplemented, read as "0"
Bit 1
T0CP1: TP0_1 pin Control
0: disable
1: enable
Bit 0
T0CP0: TP0_0 pin Control
0: disable
1: enable
TMPC1 Register – BS85C20-3/BS85C20-5
Rev. 1.40
Bit
7
6
3
2
1
0
Name
—
—
5
4
—
—
T2CP1
T2CP0
R/W
—
—
—
—
R/W
R/W
POR
—
—
—
—
0
1
Bit 7~2
Unimplemented, read as "0"
Bit 1
T2CP1: TP2_1 pin control
0: disable
1: enable
Bit 0
T2CP0: TP2_0 pin control
0: disable
1: enable
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Touch Key Flash MCU with LCD/LED Driver
TM0 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.
TM2 Function Pin Control Block Diagram – BS85C20-3/BS85C20-5 only
Note: 1. The I/O register data bits shown are used for TM output inversion control.
2. In the Capture Input Mode, the TM pin control register must never enable more than one TM input.
Rev. 1.40
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0
P B 5 o r P C 5 O u tp u t F u n c tio n
T P 1 A
1
C C R A O u tp u t
P B 5 o r P C 5
T 1 A C P 0
1
C C R A C a p tu re In p u t
0
T 1 A C P 0
T P 1 B _ 0
P B 2 o r P C 2 O u tp u t F u n c tio n
0
1
0
1
P B 2 o r P C 2
T 1 B C P 0
P B 2 o r P C 2
P B 3 o r P C 3
T P 1 B _ 1
O u tp u t F u n c tio n
0
1
0
1
P B 3 o r P C 3
T 1 B C P 1
P B 3 o r P C 3
P B 4 o r P C 4 O u tp u t F u n c tio n
C C R B O u tp u t
0
1
0
1
P B 4 o r P C 4
T 1 B C P 2
P B 4 o r P C 4
1
C C R B C a p tu re In p u t
0
T 1 B C P 2
1
0
T 1 B C P 1
1
0
T 1 B C P 0
T C K In p u t
P A 4 /T C K 1
TM1 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.
Rev. 1.40
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Programming Considerations
The TM Counter Registers and the Capture/Compare CCRA and CCRB registers, being either 10bit or 16-bit, all have a low and high byte structure. The high bytes can be directly accessed, but as
the low bytes can only be accessed via an internal 8-bit buffer, reading or writing to these register
pairs must be carried out in a specific way. The important point to note is that data transfer to and
from the 8-bit buffer and its related low byte only takes place when a write or read operation to its
corresponding high byte is executed.
As the CCRA and CCRB 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 CCRB low byte registers, named TMxAL and
TMxBL, using the following access procedures. Accessing the CCRA or CCRB low byte registers
without following these access procedures will result in unpredictable values.
The following steps show the read and write procedures:
• Writing Data to CCRB or CCRA
♦♦
Step 1. Write data to Low Byte TMxAL or TMxBL
– note that here data is only written to the 8-bit buffer.
♦♦
Step 2. Write data to High Byte TMxAH or TMxBH
– 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 CCRB or CCRA
Rev. 1.40
♦♦
Step 1. Read data from the High Byte TMxDH, TMxAH or TMxBH
– 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 TMxDL, TMxAL or TMxBL
– 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 or two external
output pins. These two external output pins can be the same signal or the inverse signal.
CTM
Name
TM No.
TM Input Pin
TM Output Pin
BS85B12-3
10-bit CTM
0
TCK0
TP0_0, TP0_1
BS85C20-3
/BS85C20-5
10-bit CTM
0
TCK0
TP0_0, TP0_1
Compact TM Operation
At its core is a 10-bit count-up counter which is driven by a user selectable internal or external clock
source. There are also two internal comparators with the names, Comparator A and Comparator
P. These comparators will compare the value in the counter with CCRP and CCRA registers. The
CCRP is three bits wide whose value is compared with the highest three bits in the counter while the
CCRA is the ten bits and therefore compares with all counter bits.
The only way of changing the value of the 10-bit counter using the application program, is to
clear the counter by changing the TnON bit from low to high. The counter will also be cleared
automatically by a counter overflow or a compare match with one of its associated comparators.
When these conditions occur, a TM interrupt signal will also usually be generated. The Compact
Type TM can operate in a number of different operational modes, can be driven by different clock
sources including an input pin and can also control an output pin. All operating setup conditions are
selected using relevant internal registers.

Compact Type TM Block Diagram
Rev. 1.40
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Touch Key Flash MCU with LCD/LED Driver
Compact Type TM Register Description
Overall operation of the Compact TM is controlled using six registers. A read only register pair
exists to store the internal counter 10-bit value, while a read/write register pair exists to store the
internal 10-bit CCRA value. The remaining two registers are control registers which setup the
different operating and control modes as well as the three CCRP bits.
Name
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
TMnC0
TnPAU
TnCK2
TnCK1
TnCK0
TnON
TnRP2
TnRP1
TnRP0
TMnC1
TnM1
TnM0
TnIO1
TnIO0
TnOC
TnPOL
TnDPX
TnCCLR
TMnDL
D7
D6
D5
D4
D3
D2
D1
D0
TMnDH
—
—
—
—
—
—
D9
D8
TMnAL
D7
D6
D5
D4
D3
D2
D1
D0
TMnAH
—
—
—
—
—
—
D9
D8
Compact TM Register List (n=0)
TMnDL Register
Bit
7
6
5
4
3
2
1
0
Name
D7
D6
D5
D4
D3
D2
D1
D0
R/W
R
R
R
R
R
R
R
R
POR
0
0
0
0
0
0
0
0
Bit 7~0
TMnDL: TMn Counter Low Byte Register bit 7 ~ bit 0
TMn 10-bit Counter bit 7 ~ bit 0
TMnDH Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
—
—
D9
D8
R/W
—
—
—
—
—
—
R
R
POR
—
—
—
—
—
—
0
0
Bit 7~2
Unimplemented, read as "0"
Bit 1~0
TMnDH: TMn Counter High Byte Register bit 1 ~ bit 0
TMn 10-bit Counter bit 9 ~ bit 8
TMnAL Register
Bit
7
6
5
4
3
2
1
0
Name
D7
D6
D5
D4
D3
D2
D1
D0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~0
TMnAL: TMn CCRA Low Byte Register bit 7 ~ bit 0
TMn 10-bit CCRA bit 7 ~ bit 0
TMnAH Register
Rev. 1.40
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
—
—
D9
D8
R/W
—
—
—
—
—
—
R/W
R/W
POR
—
—
—
—
—
—
0
0
Bit 7~2
unimplemented, read as "0"
Bit 1~0
TMn 10-bit CCRA bit 9 ~ bit 8
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TMnC0 Register
Rev. 1.40
Bit
7
6
5
4
3
2
1
0
Name
TnPAU
TnCK2
TnCK1
TnCK0
TnON
TnRP2
TnRP1
TnRP0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7
TnPAU: TMn Counter Pause Control
0: run
1: pause
The counter can be paused by setting this bit high. Clearing the bit to zero restores
normal counter operation. When in a Pause condition the TM will remain powered up
and continue to consume power. The counter will retain its residual value when this bit
changes from low to high and resume counting from this value when the bit changes
to a low value again.
Bit 6~4
TnCK2~TnCK0: Select TMn Counter clock
000: fSYS/4
001: fSYS
010: fH/16
011: fH/64
100: fTBC
101: undefined
110: TCKn rising edge clock
111: TCKn falling edge clock
These three bits are used to select the clock source for the TM. Selecting the Reserved
clock input will effectively disable the internal counter. The external pin clock source
can be chosen to be active on the rising or falling edge. The clock source fSYS is the
system clock, while fH and fTBC are other internal clocks, the details of which can be
found in the oscillator section.
Bit 3
TnON: TMn Counter On/Off Control
0: Off
1: On
This bit controls the overall on/off function of the TM. Setting the bit high enables the
counter to run, clearing the bit disables the TM. Clearing this bit to zero will stop the
counter from counting and turn off the TM which will reduce its power consumption.
When the bit changes state from low to high the internal counter value will be reset
to zero, however when the bit changes from high to low, the internal counter will
retain its residual value. If the TM is in the Compare Match Output Mode then the TM
output pin will be reset to its initial condition, as specified by the TnOC bit, when the
TnON bit changes from low to high.
Bit 2~0
TnRP2~TnRP0: TMn CCRP 3-bit register, compared with the TMn Counter bit 9~bit 7
Comparator P Match Period
000: 1024 TMn clocks
001: 128 TMn clocks
010: 256 TMn clocks
011: 384 TMn clocks
100: 512 TMn clocks
101: 640 TMn clocks
110: 768 TMn clocks
111: 896 TMn clocks
These three bits are used to setup the value on the internal CCRP 3-bit register, which
are then compared with the internal counter's highest three bits. The result of this
comparison can be selected to clear the internal counter if the TnCCLR bit is set to zero.
Setting the TnCCLR bit to zero ensures that a compare match with the CCRP values will
reset the internal counter. As the CCRP bits are only compared with the highest three
counter bits, the compare values exist in 128 clock cycle multiples. Clearing all three bits
to zero is in effect allowing the counter to overflow at its maximum value.
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TMnC1 Register
Bit
7
6
5
4
3
2
1
0
Name
TnM1
TnM0
TnIO1
TnIO0
TnOC
TnPOL
TnDPX
TnCCLR
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~6
Bit 5~4
Bit 3
Rev. 1.40
TnM1~TnM0: Select TMn Operating Mode
00: Compare Match Output Mode
01: Undefined
10: PWM Mode
11: Timer/Counter Mode
These bits setup the required operating mode for the TM. To ensure reliable operation
the TM should be switched off before any changes are made to the TnM1 and TnM0
bits. In the Timer/Counter Mode, the TM output pin control must be disabled.
TnIO1~TnIO0: Select TPn_0, TPn_1 output function
Compare Match Output Mode
00: No change
01: Output low
10: Output high
11: Toggle output
PWM Mode
00: PWM output inactive state
01: PWM output active state
10: PWM output
11: Undefined
Timer/counter Mode
unused
These two bits are used to determine how the TM output pin changes state when a
certain condition is reached. The function that these bits select depends upon in which
mode the TM is running. In the Compare Match Output Mode, the TnIO1 and TnIO0
bits determine how the TM output pin changes state when a compare match occurs
from the Comparator A. The TM output pin can be setup to switch high, switch low or
to toggle its present state when a compare match occurs from the Comparator A. When
the bits are both zero, then no change will take place on the output. The initial value
of the TM output pin should be setup using the TnOC bit in the TMnC1 register. Note
that the output level requested by the TnIO1 and TnIO0 bits must be different from
the initial value setup using the TnOC bit otherwise no change will occur on the TM
output pin when a compare match occurs. After the TM output pin changes state it can
be reset to its initial level by changing the level of the TnON bit from low to high.
In the PWM Mode, the TnIO1 and TnIO0 bits determine how the TM output pin
changes state when a certain compare match condition occurs. The PWM output
function is modified by changing these two bits. It is necessary to change the values
of the TnIO1 and TnIO0 bits only after the TMn has been switched off. Unpredictable
PWM outputs will occur if the TnIO1 and TnIO0 bits are changed when the TM is
running
TnOC: TPn_0, TPn_1 Output control bit
Compare Match Output Mode
0: Initial low
1: Initial high
PWM Mode
0: Active low
1: Active high
This is the output control bit for the TM output pin. Its operation depends upon whether
TM is being used in the Compare Match Output Mode or in the PWM Mode. It has no
effect if the TM is in the Timer/Counter Mode. In the Compare Match Output Mode it
determines the logic level of the TM output pin before a compare match occurs. In the
PWM Mode it determines if the PWM signal is active high or active low.
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Bit 2
TnPOL: TPn_0, TPn_1 Output polarity Control
0: Non-invert
1: Invert
This bit controls the polarity of the TPn_0 or TPn_1 output pin. When the bit is set
high the TM output pin will be inverted and not inverted when the bit is zero. It has no
effect if the TM is in the Timer/Counter Mode.
Bit 1
TnDPX: TMn PWM period/duty Control
0: CCRP - period; CCRA - duty
1: CCRP - duty; CCRA - period
This bit, determines which of the CCRA and CCRP registers are used for period and
duty control of the PWM waveform.
Bit 0
TnCCLR: Select TMn Counter clear condition
0: TMn Comparatror P match
1: TMn Comparatror A match
This bit is used to select the method which clears the counter. Remember that the
Compact TM contains two comparators, Comparator A and Comparator P, either of
which can be selected to clear the internal counter. With the TnCCLR bit set high,
the counter will be cleared when a compare match occurs from the Comparator A.
When the bit is low, the counter will be cleared when a compare match occurs from
the Comparator P or with a counter overflow. A counter overflow clearing method can
only be implemented if the CCRP bits are all cleared to zero. The TnCCLR bit is not
used in the PWM Mode.
Compact Type TM Operating Modes
The Compact Type TM can operate in one of three operating modes, Compare Match Output Mode,
PWM Mode or Timer/Counter Mode. The operating mode is selected using the TnM1 and TnM0
bits in the TMnC1 register.
Compare Match Output Mode
To select this mode, bits TnM1 and TnM0 in the TMnC1 register, should be set to "00" respectively.
In this mode once the counter is enabled and running it can be cleared by three methods. These are
a counter overflow, a compare match from Comparator A and a compare match from Comparator P.
When the TnCCLR bit is low, there are two ways in which the counter can be cleared. One is when
a compare match occurs from Comparator P, the other is when the CCRP bits are all zero which
allows the counter to overflow. Here both TnAF and TnPF interrupt request flags for the Comparator
A and Comparator P respectively, will both be generated.
If the TnCCLR bit in the TMnC1 register is high then the counter will be cleared when a compare
match occurs from Comparator A. However, here only the TnAF interrupt request flag will be
generated even if the value of the CCRP bits is less than that of the CCRA registers. Therefore when
TnCCLR is high no TnPF interrupt request flag will be generated. If the CCRA bits are all zero, the
counter will overflow when its reaches its maximum 10-bit, 3FF Hex, value, however here the TnAF
interrupt request flag will not be generated.
Rev. 1.40
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Touch Key Flash MCU with LCD/LED Driver
As the name of the mode suggests, after a comparison is made, the TM output pin will change state.
The TM output pin condition however only changes state when an TnAF interrupt request flag
is generated after a compare match occurs from Comparator A. The TnPF interrupt request flag,
generated from a compare match occurs from Comparator P, will have no effect on the TM output
pin. The way in which the TM output pin changes state are determined by the condition of the
TnIO1 and TnIO0 bits in the TMnC1 register. The TM output pin can be selected using the TnIO1
and TnIO0 bits to go high, to go low or to toggle from its present condition when a compare match
occurs from Comparator A. The initial condition of the TM output pin, which is setup after the
TnON bit changes from low to high, is setup using the TnOC bit. Note that if the TnIO1 and TnIO0
bits are zero then no pin change will take place.
Counte� Value
CCRP = 0
Counte�
ove�flow
TnCCLR = 0; Tn�[1:0] = 00
CCRP > 0
Counte� �lea�ed by CCRP value
CCRP > 0
0x3FF
CCRP
Pause Resume
CCRA
Stop
Counte�
Reset
Time
TnON
TnPAU
TnAPOL
CCRP Int.
Flag TnPF
üüüü
Flag TnAF
T� O/P Pin
Output Pin set
to Initial Level
Low if TnOC = 0
Output Toggle
wit� TnAF flag
Now TnIO [1:0] = 10
A�tive Hig� Output
Sele�t
Output not affe�ted by
TnAF flag. Remains Hig�
until �eset by TnON bit
He�e TnIO [1:0] = 11
Toggle Output Sele�t
Output inve�ts
w�en TnPOL is �ig�
Output Pin
Reset to initial value
Output �ont�olled
by ot�e� pin-s�a�ed fun�tion
Compare Match Output Mode – TnCCLR = 0
Note: 1. With TnCCLR=0, a Comparator P match will clear the counter
2. The TM output pin is controlled only by the TnAF flag
3. The output pin is reset to its initial state by a TnON bit rising edge
Rev. 1.40
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Touch Key Flash MCU with LCD/LED Driver
TnCCLR = 1; Tn� [1:0] = 00
Counte� Value
CCRA = 0
Counte� ove�flows
CCRA > 0 Counte� �lea�ed by CCRA value
0x3FF
CCRA = 0
CCRA
Pause Resume
Stop
CCRP
Counte�
Reset
Time
TnON
TnPAU
TnPOL
No TnAF flag
gene�ated on
CCRA ove�flow
CCRA Int.
Flag TnAF
CCRP Int.
Flag TnPF
T� O/P Pin
TnPF not
gene�ated
Output Pin set
to Initial Level
Low if TnOC = 0
Output
does
not ��ange
Output not affe�ted by
TnAF flag �emains Hig�
until �eset by TnON bit
Output Toggle
wit� TnAF flag
Now TnIO [1:0] = 10
A�tive Hig� Output
Sele�t
He�e TnIO [1:0] = 11
Toggle Output Sele�t
Output inve�ts
w�en TnPOL is �ig�
Output �ont�olled by
ot�e� pin-s�a�ed fun�tion
Output Pin
Reset to initial value
Compare Match Output Mode – TnCCLR = 1
Note: 1. With TnCCLR=1, a Comparator A match will clear the counter
2. The TM output pin is controlled only by the TnAF flag
3. The output pin is reset to its initial state by a TnON bit rising edge
4. The TnPF flag is not generated when TnCCLR=1
Timer/Counter Mode
To select this mode, bits TnM1 and TnM0 in the TMnC1 register should be set to 11 respectively.
The Timer/Counter Mode operates in an identical way to the Compare Match Output Mode
generating the same interrupt flags. The exception is that in the Timer/Counter Mode the TM output
pin is not used. Therefore the above description and Timing Diagrams for the Compare Match
Output Mode can be used to understand its function. As the TM output pin is not used in this mode,
the pin can be used as a normal I/O pin or other pin-shared function.
Rev. 1.40
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Touch Key Flash MCU with LCD/LED Driver
PWM Output Mode
To select this mode, bits TnM1 and TnM0 in the TMnC1 register should be set to 10 respectively.
The PWM function within the TM is useful for applications which require functions such as motor
control, heating control, illumination control etc. By providing a signal of fixed frequency but
of varying duty cycle on the TM output pin, a square wave AC waveform can be generated with
varying equivalent DC RMS values.
As both the period and duty cycle of the PWM waveform can be controlled, the choice of generated
waveform is extremely flexible. In the PWM mode, the TnCCLR bit has no effect on the PWM
operation. Both of the CCRA and CCRP registers are used to generate the PWM waveform, one
register is used to clear the internal counter and thus control the PWM waveform frequency, while
the other one is used to control the duty cycle. Which register is used to control either frequency
or duty cycle is determined using the TnDPX bit in the TMnC1 register. The PWM waveform
frequency and duty cycle can therefore be controlled by the values in the CCRA and CCRP registers.
An interrupt flag, one for each of the CCRA and CCRP, will be generated when a compare match
occurs from either Comparator A or Comparator P. The TnOC bit in the TMnC1 register is used to
select the required polarity of the PWM waveform while the two TnIO1 and TnIO0 bits are used to
enable the PWM output or to force the TM output pin to a fixed high or low level. The TnPOL bit is
used to reverse the polarity of the PWM output waveform.
Counte� Value
Counte� Clea�ed
by CCRP
TnDPX = 0; Tn� [1:0] = 10
CCRP
Pause Resume
Counte� �eset
Counte� Stop w�en TnON
if TnON bit low �etu�ns �ig�
CCRA
Time
TnON
TnPAU
TnPOL
CCRA Int.
Flag TnAF
CCRP Int.
Flag TnPF
T� O/P Pin
TnOC = 1
T� O/P Pin
TnOC = 0
PW� Duty Cy�le
set by CCRA
PW� Pe�iod
set by CCRP
PW� �esumes
ope�ation
Output �ont�olled by
Output Inve�ts
ot�e� pin-s�a�ed fun�tion
W�en TnPOL = 1
PWM Mode – TnDPX = 0
Note: 1. Here TnDPX=0 -- Counter cleared by CCRP
2. A counter clear sets the PWM Period
3. The internal PWM function continues even when TnIO [1:0] = 00 or 01
4. The TnCCLR bit has no influence on PWM operation
Rev. 1.40
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Touch Key Flash MCU with LCD/LED Driver
Counte� Clea�ed
by CCRA
Counte� Value
TnDPX = 1; Tn� [1:0] = 10
CCRA
Counte� �eset
Counte� Stop w�en TnON
if TnON bit low �etu�ns �ig�
Pause Resume
CCRP
Time
TnON
TnPAU
TnPOL
CCRA Int.
Flag TnAF
CCRP Int.
Flag TnPF
T� O/P Pin
TnOC = 1
T� O/P Pin
TnOC = 0
PW� �esumes
ope�ation
PW� Duty Cy�le
set by CCRP
Output �ont�olled by
ot�e� pin-s�a�ed fun�tion
PW� Pe�iod
set by CCRA
Output Inve�ts
W�en TnPOL = 1
PWM Mode – TnDPX = 1
Note: 1. Here TnDPX = 1 -- Counter cleared by CCRA
2. A counter clear sets the PWM Period
3. The internal PWM function continues even when TnIO [1:0] = 00 or 01
4. The TnCCLR bit has no influence on PWM operation
CTM, PWM Mode, Edge-aligned Mode, T0DPX=0
CCRP
001b
010b
011b
100b
101b
110b
111b
000b
Period
128
256
384
512
640
768
896
1024
Duty
CCRA
If fSYS = 16MHz, TM clock source is fSYS/4, CCRP = 100b and CCRA =128,
The CTM PWM output frequency = (fSYS/4) / 512 = fSYS/2048 = 7.8125 kHz, duty = 128/512 = 25%.
If the Duty value defined by the CCRA register is equal to or greater than the Period value, then the
PWM output duty is 100%.
CTM, PWM Mode, Edge-aligned Mode, T0DPX=1
CCRP
001b
010b
011b
100b
Period
Duty
101b
110b
111b
000b
768
896
1024
CCRA
128
256
384
512
640
The output period is determined by the CCRA register value together with the TM clock while the
PWM duty cycle is defined by the CCRP register value.
Rev. 1.40
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Touch Key Flash MCU with LCD/LED Driver
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 an external input pin and can drive one or two external output pins.
CTM
Name
TM No.
TM Input Pin
TM Output Pin
BS85B12-3
—
—
—
—
BS85C20-3
/BS85C20-5
10-bit STM
2
TCK2
TP2_0, TP2_1
Standard TM Operation
At its core is a 10-bit count-up counter which is driven by a user selectable internal or external clock
source. There are also two internal comparators with the names, Comparator A and Comparator
P. These comparators will compare the value in the counter with CCRP and CCRA registers. The
CCRP is three bits wide whose value is compared with the highest three bits in the counter while the
CCRA is the ten bits and therefore compares with all counter bits.
The only way of changing the value of the 10-bit counter using the application program, is to
clear the counter by changing the TnON bit from low to high. The counter will also be cleared
automatically by a counter overflow or a compare match with one of its associated comparators.
When these conditions occur, a TM interrupt signal will also usually be generated. The Standard
Type TM can operate in a number of different operational modes, can be driven by different clock
sources including an input pin and can also control an output pin. All operating setup conditions are
selected using relevant internal registers.

Standard Type TM Block Diagram
Rev. 1.40
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Touch Key Flash MCU with LCD/LED Driver
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 10-bit value, while a read/write register pair exists to store
the internal 10-bit CCRA value. The remaining two registers are control registers which setup the
different operating and control modes as well as the three CCRP bits.
STM Register List
Name
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
TM2C0
T2PAU
T2CK2
T2CK1
T2CK0
T2ON
T2RP2
T2RP1
T2RP0
TM2C1
T2M1
T2M0
T2IO1
T2IO0
T2OC
T2POL
T2DPX
T2CCLR
TM2DL
D7
D6
D5
D4
D3
D2
D1
D0
TM2DH
—
—
—
—
—
—
D9
D8
TM2AL
D7
D6
D5
D4
D3
D2
D1
D0
TM2AH
—
—
—
—
—
—
D9
D8
10-bit Standard TM Register List
TM2C0 Register
Rev. 1.40
Bit
7
6
5
4
3
2
1
0
Name
T2PAU
T2CK2
T2CK1
T2CK0
T2ON
T2RP2
T2RP1
T2RP0
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
T2PAU: TM2 Counter Pause Control
0: run
1: pause
The counter can be paused by setting this bit high. Clearing the bit to zero restores
normal counter operation. When in a Pause condition the TM will remain powered up
and continue to consume power. The counter will retain its residual value when this bit
changes from low to high and resume counting from this value when the bit changes
to a low value again.
Bit 6~4
T2CK2~T2CK0: Select TM2 Counter clock
000: fSYS/4
001: fSYS
010: fH/16
011: fH/64
100: fTBC
101: undefined
110: TCK2 rising edge clock
111: TCK2 falling edge clock
These three bits are used to select the clock source for the TM. Selecting the Reserved
clock input will effectively disable the internal counter. The external pin clock source
can be chosen to be active on the rising or falling edge. The clock source fSYS is the
system clock, while fH and fTBC are other internal clocks, the details of which can be
found in the oscillator section.
Bit 3
T2ON: TM2 Counter On/Off Control
0: Off
1: On
This bit controls the overall on/off function of the TM. Setting the bit high enables the
counter to run, clearing the bit disables the TM. Clearing this bit to zero will stop the
counter from counting and turn off the TM which will reduce its power consumption.
When the bit changes state from low to high the internal counter value will be reset to
zero, however when the bit changes from high to low, the internal counter will retain
its residual value until the bit returns high again.
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Touch Key Flash MCU with LCD/LED Driver
If the TM is in the Compare Match Output Mode then the TM output pin will be reset
to its initial condition, as specified by the T2OC bit, when the T2ON bit changes from
low to high.
Bit 2~0
T2RP2~T2RP0: TM2 CCRP 3-bit register, compared with the TM2 Counter bit 9~bit 7
Comparator P Match Period
000: 1024 TM2 clocks
001: 128 TM2 clocks
010: 256 TM2 clocks
011: 384 TM2 clocks
100: 512 TM2 clocks
101: 640 TM2 clocks
110: 768 TM2 clocks
111: 896 TM2 clocks
These three bits are used to setup the value on the internal CCRP 3-bit register, which
are then compared with the internal counter's highest three bits. The result of this
comparison can be selected to clear the internal counter if the T2CCLR bit is set to
zero. Setting the T2CCLR bit to zero ensures that a compare match with the CCRP
values will reset the internal counter. As the CCRP bits are only compared with the
highest three counter bits, the compare values exist in 128 clock cycle multiples.
Clearing all three bits to zero is in effect allowing the counter to overflow at its
maximum value.
TM2C1 Register
Rev. 1.40
Bit
7
6
5
4
3
2
1
0
Name
T2M1
T2M0
T2IO1
T2IO0
T2OC
T2POL
T2DPX
T2CCLR
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
T2M1~T2M0: Select TM2 Operating Mode
00: Compare Match Output Mode
01: Capture Input Mode
10: PWM Mode or Single Pulse Output Mode
11: Timer/Counter Mode
These bits setup the required operating mode for the TM. To ensure reliable operation
the TM should be switched off before any changes are made to the T2M1 and T2M0
bits. In the Timer/Counter Mode, the TM output pin control must be disabled.
Bit 5~4
T2IO1~T2IO0: Select TP2_0, TP2_1 output function
Compare Match Output Mode
00: No change
01: Output low
10: Output high
11: Toggle output
PWM Mode/Single Pulse Output Mode
00: PWM output inactive state
01: PWM output active state
10: PWM output
11: Single pulse output
Capture Input Mode
00: Input capture at rising edge of TP2_0, TP2_1
01: Input capture at falling edge of TP2_0, TP2_1
10: Input capture at falling/rising edge of TP2_0, TP2_1
11: Input capture disabled
Timer/counter Mode:
Unused
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Touch Key Flash MCU with LCD/LED Driver
These two bits are used to determine how the TM output pin changes state when a
certain condition is reached. The function that these bits select depends upon in which
mode the TM is running. In the Compare Match Output Mode, the T2IO1 and T2IO0
bits determine how the TM output pin changes state when a compare match occurs
from the Comparator A. The TM output pin can be setup to switch high, switch low or
to toggle its present state when a compare match occurs from the Comparator A. When
the bits are both zero, then no change will take place on the output. The initial value
of the TM output pin should be setup using the T2OC bit in the TM2C1 register. Note
that the output level requested by the T2IO1 and T2IO0 bits must be different from
the initial value setup using the T2OC bit otherwise no change will occur on the TM
output pin when a compare match occurs. After the TM output pin changes state it can
be reset to its initial level by changing the level of the T2ON bit from low to high.
In the PWM Mode, the T2IO1 and T2IO0 bits determine how the TM output pin
changes state when a certain compare match condition occurs. The PWM output
function is modified by changing these two bits. It is necessary to change the values
of the T2IO1 and T2IO0 bits only after the TM has been switched off. Unpredictable
PWM outputs will occur if the T2IO1 and T2IO0 bits are changed when the TM is
running
Rev. 1.40
Bit 3
T2OC: TP2_0, TP2_1 Output control bit
Compare Match Output Mode
0: initial low
1: initial high
PWM Mode/ Single Pulse Output Mode
0: Active low
1: Active high
This is the output control bit for the TM output pin. Its operation depends upon
whether TM is being used in the Compare Match Output Mode or in the PWM Mode/
Single Pulse Output Mode. It has no effect if the TM is in the Timer/Counter Mode. In
the Compare Match Output Mode it determines the logic level of the TM output pin
before a compare match occurs. In the PWM Mode it determines if the PWM signal is
active high or active low.
Bit 2
T2POL: TP2_0, TP2_1 Output polarity Control
0: non-invert
1: invert
This bit controls the polarity of the TP2_0 or TP2_1 output pin. When the bit is set
high the TM output pin will be inverted and not inverted when the bit is zero. It has no
effect if the TM is in the Timer/Counter Mode.
Bit 1
T2DPX: TM1 PWM period/duty Control
0: CCRP - period; CCRA - duty
1: CCRP - duty; CCRA - period
This bit, determines which of the CCRA and CCRP registers are used for period and
duty control of the PWM waveform.
Bit 0
T2CCLR: Select TM1 Counter clear condition
0: TM2 Comparatror P match
1: TM2 Comparatror 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 T2CCLR 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 T2CCLR bit is not
used in the PWM, Single Pulse or Input Capture Mode.
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TM2DL 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
TM2DL: TM2 Counter Low Byte Register bit 7~bit 0
TM2 10-bit Counter bit 7~bit 0
TM2DH Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
—
—
D9
D8
R/W
—
—
—
—
—
—
R
R
POR
—
—
—
—
—
—
0
0
2
1
0
Bit 7~2
Unimplemented, read as "0"
Bit 1~0
TM2DH: TM2 Counter High Byte Register bit 1~bit 0
TM2 10-bit Counter bit 9~bit 8
TM2AL Register
Bit
7
6
5
4
3
Name
D7
D6
D5
D4
D3
D2
D1
D0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~0
TM2AL: TM2 CCRA Low Byte Register bit 7~bit 0
TM2 10-bit CCRA bit 7~bit 0
TM2AH Registe
Rev. 1.40
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
TM2AH: TM2 CCRA High Byte Register bit 1~bit 0
TM2 10-bit CCRA bit 9~bit 8
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Touch Key Flash MCU with LCD/LED Driver
Standard Type TM Operating Modes
The Standard Type TM can operate in one of five operating modes, Compare Match Output
Mode, PWM Mode, Single Pulse Output Mode, Capture Input Mode or Timer/Counter Mode. The
operating mode is selected using the TnM1 and TnM0 bits in the TMnC1 register.
Compare Match Output Mode
To select this mode, bits TnM1 and TnM0 in the TMnC1 register, should be set to 00 respectively.
In this mode once the counter is enabled and running it can be cleared by three methods. These are
a counter overflow, a compare match from Comparator A and a compare match from Comparator P.
When the TnCCLR bit is low, there are two ways in which the counter can be cleared. One is when
a compare match from Comparator P, the other is when the CCRP bits are all zero which allows
the counter to overflow. Here both TnAF and TnPF interrupt request flags for Comparator A and
Comparator P respectively, will both be generated.
If the TnCCLR bit in the TMnC1 register is high then the counter will be cleared when a compare
match occurs from Comparator A. However, here only the TnAF interrupt request flag will be
generated even if the value of the CCRP bits is less than that of the CCRA registers. Therefore when
TnCCLR is high no TnPF interrupt request flag will be generated. In the Compare Match Output
Mode, the CCRA can not be set to 0.
Counte� Value
CCRP = 0
Counte�
ove�flow
TnCCLR = 0; Tn�[1:0] = 00
CCRP > 0
Counte� �lea�ed by CCRP value
CCRP > 0
0x3FF
CCRP
Pause Resume
CCRA
Stop
Counte�
Reset
Time
TnON
TnPAU
TnAPOL
CCRP Int.
Flag TnPF
üüüü
Flag TnAF
T� O/P Pin
Output Pin set
to Initial Level
Low if TnOC = 0
Output Toggle
wit� TnAF flag
Now TnIO [1:0] = 10
A�tive Hig� Output
Sele�t
Output not affe�ted by
TnAF flag. Remains Hig�
until �eset by TnON bit
He�e TnIO [1:0] = 11
Toggle Output Sele�t
Output inve�ts
w�en TnPOL is �ig�
Output Pin
Reset to initial value
Output �ont�olled
by ot�e� pin-s�a�ed fun�tion
Compare Match Output Mode – TnCCLR = 0
Note: 1. With TnCCLR=0 a Comparator P match will clear the counter
2. The TM output pin is controlled only by the TnAF flag
3. The output pin is reset to itsinitial state by a TnON bit rising edge
Rev. 1.40
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Touch Key Flash MCU with LCD/LED Driver
As the name of the mode suggests, after a comparison is made, the TM output pin, will change
state. The TM output pin condition however only changes state when a TnAF interrupt request flag
is generated after a compare match occurs from Comparator A. The TnPF interrupt request flag,
generated from a compare match occurs from Comparator P, will have no effect on the TM output
pin. The way in which the TM output pin changes state are determined by the condition of the
TnIO1 and TnIO0 bits in the TMnC1 register. The TM output pin can be selected using the TnIO1
and TnIO0 bits to go high, to go low or to toggle from its present condition when a compare match
occurs from Comparator A. The initial condition of the TM output pin, which is setup after the
TnON bit changes from low to high, is setup using the TnOC bit. Note that if the TnIO1 and TnIO0
bits are zero then no pin change will take place.
Timer/Counter Mode
To select this mode, bits TnM1 and TnM0 in the TMnC1 register should be set to 11 respectively.
The Timer/Counter Mode operates in an identical way to the Compare Match Output Mode
generating the same interrupt flags. The exception is that in the Timer/Counter Mode the TM output
pin is not used. Therefore the above description and Timing Diagrams for the Compare Match
Output Mode can be used to understand its function. As the TM output pin is not used in this mode,
the pin can be used as a normal I/O pin or other pin-shared function.
TnCCLR = 1; Tn� [1:0] = 00
Counte� Value
CCRA = 0
Counte� ove�flows
CCRA > 0 Counte� �lea�ed by CCRA value
0x3FF
CCRA = 0
CCRA
Pause Resume
Stop
CCRP
Counte�
Reset
Time
TnON
TnPAU
TnPOL
No TnAF flag
gene�ated on
CCRA ove�flow
CCRA Int.
Flag TnAF
CCRP Int.
Flag TnPF
T� O/P Pin
TnPF not
gene�ated
Output Pin set
to Initial Level
Low if TnOC = 0
Output
does
not ��ange
Output not affe�ted by
TnAF flag �emains Hig�
until �eset by TnON bit
Output Toggle
wit� TnAF flag
Output inve�ts
w�en TnPOL is �ig�
Output �ont�olled by
ot�e� pin-s�a�ed fun�tion
Output Pin
Reset to initial value
Now TnIO [1:0] = 10
A�tive Hig� Output
Sele�t
He�e TnIO [1:0] = 11
Toggle Output Sele�t
Compare Match Output Mode – TnCCLR = 1
Note: 1. With TnCCLR=1 a Comparator A match will clear the counter
2. The TM output pin is controlled only by the TnAF flag
3. The output pin is reset to its initial state by a TnON bit rising edge
4. A TnPF flag is not generated when TnCCLR=1
Rev. 1.40
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Touch Key Flash MCU with LCD/LED Driver
PWM Output Mode
To select this mode, bits TnM1 and TnM0 in the TMnC1 register should be set to 10 respectively.
The PWM function within the TM is useful for applications which require functions such as motor
control, heating control, illumination control etc. By providing a signal of fixed frequency but
of varying duty cycle on the TM output pin, a square wave AC waveform can be generated with
varying equivalent DC RMS values.
As both the period and duty cycle of the PWM waveform can be controlled, the choice of generated
waveform is extremely flexible. In the PWM mode, the TnCCLR bit has no effect on the PWM
operation. Both of the CCRA and CCRP registers are used to generate the PWM waveform, one
register is used to clear the internal counter and thus control the PWM waveform frequency, while
the other one is used to control the duty cycle. Which register is used to control either frequency
or duty cycle is determined using the TnDPX bit in the TMnC1 register. The PWM waveform
frequency and duty cycle can therefore be controlled by the values in the CCRA and CCRP registers.
An interrupt flag, one for each of the CCRA and CCRP, will be generated when a compare match
occurs from either Comparator A or Comparator P. The TnOC bit in the TMnC1 register is used to
select the required polarity of the PWM waveform while the two TnIO1 and TnIO0 bits are used to
enable the PWM output or to force the TM output pin to a fixed high or low level. The TnPOL bit is
used to reverse the polarity of the PWM output waveform.
STM, PWM Mode, Edge-aligned Mode, TnDPX=0
CCRP
001b
010b
011b
100b
101b
110b
111b
000b
Period
128
256
384
512
640
768
896
1024
Duty
CCRA
If fSYS = 16MHz, TM clock source is fSYS/4, CCRP = 100b and CCRA =128,
The STM PWM output frequency = (fSYS/4) / 512 = fSYS/2048 = 7.8125 kHz, 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%.
STM, PWM Mode, Edge-aligned Mode, TnDPX=1
CCRP
001b
010b
011b
100b
Period
Duty
101b
110b
111b
000b
768
896
1024
CCRA
128
256
384
512
640
The PWM output period is determined by the CCRA register value together with the TM clock
while the PWM duty cycle is defined by the CCRP register value.
Rev. 1.40
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Touch Key Flash MCU with LCD/LED Driver
Counte� Value
Counte� Clea�ed
by CCRP
TnDPX = 0; Tn� [1:0] = 10
CCRP
Pause Resume
Counte� �eset
Counte� Stop w�en TnON
if TnON bit low �etu�ns �ig�
CCRA
Time
TnON
TnPAU
TnPOL
CCRA Int.
Flag TnAF
CCRP Int.
Flag TnPF
T� O/P Pin
TnOC = 1
T� O/P Pin
TnOC = 0
PW� Duty Cy�le
set by CCRA
PW� Pe�iod
set by CCRP
PW� �esumes
ope�ation
Output �ont�olled by
Output Inve�ts
ot�e� pin-s�a�ed fun�tion
W�en TnPOL = 1
PWM Mode – TnDPX = 0
Note: 1. Here TnDPX=0 – Counter cleared by CCRP
2. A counter clear sets the PWM Period
3. The internal PWM function continues running even when TnIO [1:0] = 00 or 01
4. The TnCCLR bit has no influence on PWM operation
Rev. 1.40
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Touch Key Flash MCU with LCD/LED Driver
Counte� Value
Counte� Clea�ed
by CCRA
TnDPX = 1; Tn� [1:0] = 10
CCRA
Pause Resume
Counte� �eset
Counte� Stop w�en TnON
if TnON bit low �etu�ns �ig�
CCRP
Time
TnON
TnPAU
TnPOL
CCRA Int.
Flag TnAF
CCRP Int.
Flag TnPF
T� O/P Pin
TnOC = 1
T� O/P Pin
TnOC = 0
PW� �esumes
ope�ation
PW� Duty Cy�le
set by CCRP
PW� Pe�iod
set by CCRA
Output �ont�olled by
ot�e� pin-s�a�ed fun�tion
Output Inve�ts
W�en TnPOL = 1
PWM Mode – TnDPX = 1
Note: 1. Here TnDPX=1 – Counter cleared by CCRA
2. A counter clear sets the PWM Period
3. The internal PWM function continues even when TnIO [1:0] = 00 or 01
4. The TnCCLR bit has no influence on PWM operation
Single Pulse Mode
To select this mode, bits TnM1 and TnM0 in the TMnC1 register should be set to 10 respectively
and also the TnIO1 and TnIO0 bits should be set to 11 respectively. The Single Pulse Output Mode,
as the name suggests, will generate a single shot pulse on the TM output pin.
The trigger for the pulse output leading edge is a low to high transition of the TnON bit, which can
be implemented using the application program. However in the Single Pulse Mode, the TnON bit
can also be made to automatically change from low to high using the external TCKn pin, which will
in turn initiate the Single Pulse output. When the TnON bit transitions to a high level, the counter
will start running and the pulse leading edge will be generated. The TnON bit should remain high
when the pulse is in its active state. The generated pulse trailing edge will be generated when the
TnON bit is cleared to zero, which can be implemented using the application program or when a
compare match occurs from Comparator A.
Rev. 1.40
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Touch Key Flash MCU with LCD/LED Driver
Single Pulse Generation
However a compare match from Comparator A will also automatically clear the TnON bit and thus
generate the Single Pulse output trailing edge. In this way the CCRA value can be used to control
the pulse width. A compare match from Comparator A will also generate a TM interrupt. The counter
can only be reset back to zero when the TnON bit changes from low to high when the counter
restarts. In the Single Pulse Mode CCRP is not used. The TnCCLR and TnDPX bits are not used in
this Mode.
Tn� [1:0] = 10; TnIO [1:0] = 11
Counte� Stopped
by CCRA
Counte� Value
CCRA
Pause
Counte� �eset
Counte� Stops w�en TnON
by softwa�e
�etu�ns �ig�
Resume
CCRP
Time
TnON
Softwa�e
T�igge�
TCn pin
Clea�ed by
CCRA mat��
Auto. set
by TCKn pin
Softwa�e
T�igge�
Softwa�e
T�igge�
Softwa�e
Clea�
Softwa�e
T�igge�
TCKn pin
T�igge�
TnPAU
TnPOL
No CCRP
Inte��upt
gene�ated
CCRP Int.
Flag TnPF
CCRA Int.
Flag TnAF
TnIO1� TnIO0 = 00
Output Ina�tive
TnIO1� TnIO0 = 11 Single Pulse Output
TnIO1� TnIO0 = 11
T� O/P Pin
TnOC = 1
T� O/P Pin
TnOC = 0
Output Inve�ts
W�en TnPOL = 1
Pulse Widt�
set by CCRA
Single Pulse Mode
Note: 1. Counter stopped by CCRA
2. CCRP is not used
3. The pulse is triggered by the TCKn pin or by setting the TnON bit high
4. A TCKn pin active edge will automatically set the TnON bit high
5. In the Single Pulse Mode, TnIO [1:0] must be set to "11" and can not be changed.
Rev. 1.40
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BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Capture Input Mode
To select this mode bits TnM1 and TnM0 in the TMnC1 register should be set to 01 respectively.
This mode enables external signals to capture and store the present value of the internal counter
and can therefore be used for applications such as pulse width measurements. The external signal is
supplied on the TPn_0 or TPn_1 pin, whose active edge can be either a rising edge, a falling edge or
both rising and falling edges; the active edge transition type is selected using the TnIO1 and TnIO0
bits in the TMnC1 register. The counter is started when the TnON bit changes from low to high
which is initiated using the application program.
When the required edge transition appears on the TPn_0 or TPn_1 pin, the present value in the
counter will be latched into the CCRA registers and a TM interrupt generated. Irrespective of
what events occur on the TPn_0 or TPn_1 pin the counter will continue to free run until the TnON
bit changes from high to low. When a CCRP compare match occurs, the counter will reset back
to zero; in this way the CCRP value can be used to control the maximum counter value. When a
CCRP compare match occurs from Comparator P, a TM interrupt will also be generated. Counting
the number of overflow interrupt signals from the CCRP can be a useful method in measuring long
pulse widths. The TnIO1 and TnIO0 bits can select the active trigger edge on the TPn_0 or TPn_1
pin to be a rising edge, falling edge or both edge types. If the TnIO1 and TnIO0 bits are both set
high, then no capture operation will take place irrespective of what happens on the TPn_0 or TPn_1
pin, however it must be noted that the counter will continue to run.
As the TPn_0 or TPn_1 pin is pin shared with other functions, care must be taken if the TM is in the Input
Capture Mode. This is because if the pin is setup as an output, then any transitions on this pin may cause
an input capture operation to be executed. The TnCCLR and TnDPX bits are not used in this Mode.
Counte�
Value
Tn� [1:0] = 01
Counte�
ove�flow
CCRP
Stop
Counte�
Reset
YY
Pause
XX
Resume
Time
TnON
TnPAU
T� Captu�e
Pin TPn
A�tive
edge
A�tive
edge
A�tive
edge
CCRA Int.
Flag TnAF
CCRP Int.
Flag TnPF
CCRA
Value
TnIO [1:0]
Value
XX
00 - Rising edge
YY
01 - Falling edge
XX
10 - Bot� edges
YY
11 -
Disable Captu�e
Capture Input Mode
Note: 1.. TnM [1:0] = 01 and active edge set by the TnIO [1:0] bits
2. A TM Capture input pin active edge transfers the counter value to CCRA
3. TnCCLR bit not used
4. No output function -- TnOC and TnPOL bits are not used
5. CCRP determines the counter value and the counter has a maximum count value when CCRP is
equal to zero.
Rev. 1.40
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BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Enhanced Type TM – ETM
The Enhanced Type TM contains five operating modes, which are Compare Match Output, Timer/
Event Counter, Capture Input, Single Pulse Output and PWM Output modes. The Enhanced TM can
also be controlled with an external input pin and can drive three or four external output pins.
CTM
Name
TM No.
TM Input Pin
TM Output Pin
BS85B12-3
10-bit ETM
1
TCK1
TP1A, TP1B_0, TP1B_1, TP1B_2
BS85C20-3
/BS85C20-5
10-bit ETM
1
TCK1
TP1A, TP1B_0, TP1B_1, TP1B_2
Enhanced TM Operation
At its core is a 10-bit count-up/count-down counter which is driven by a user selectable internal
or external clock source. There are three internal comparators with the names, Comparator A,
Comparator B and Comparator P. These comparators will compare the value in the counter with the
CCRA, CCRB and CCRP registers. The CCRP comparator is 3-bits wide whose value is compared
with the highest 3-bits in the counter while CCRA and CCRB are 10-bits wide and therefore
compared with all counter bits.
The only way of changing the value of the 10-bit counter using the application program, is to
clear the counter by changing the TnON bit from low to high. The counter will also be cleared
automatically by a counter overflow or a compare match with one of its associated comparators.
When these conditions occur, a TM interrupt signal will also usually be generated. The Enhanced
Type TM can operate in a number of different operational modes, can be driven by different clock
sources including an input pin and can also control output pins. All operating setup conditions are
selected using relevant internal registers.

Enhanced Type TM Block Diagram
Rev. 1.40
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Touch Key Flash MCU with LCD/LED Driver
Enhanced Type TM Register Description
Overall operation of the Enhanced TM is controlled using a series of registers. A read only register
pair exists to store the internal counter 10-bit value, while two read/write register pairs exist to store
the internal 10-bit CCRA and CCRB value. The remaining three registers are control registers which
setup the different operating and control modes as well as the three CCRP bits.
Name
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
TM1C0
T1PAU
T1CK2
T1CK1
T1CK0
T1ON
T1RP2
T1RP1
T1RP0
TM1C1
T1AM1
T1AM0
T1AIO1
T1AIO0
T1AOC
T1APOL
T1CDN
T1CCLR
TM1C2
T1BM1
T1BM0
T1BIO1
T1BIO0
T1BOC
T1BPOL
T1PWM1 T1PWM0
TM1DL
D7
D6
D5
D4
D3
D2
D1
TM1DH
—
—
—
—
—
—
D9
D0
D8
TM1AL
D7
D6
D5
D4
D3
D2
D1
D0
TM1AH
—
—
—
—
—
—
D9
D8
TM1BL
D7
D6
D5
D4
D3
D2
D1
D0
TM1BH
—
—
—
—
—
—
D9
D8
10-bit Enhanced TM Register List
10-bit Enhanced TM Register List
• TM1C0 Register – 10-bit ETM
Rev. 1.40
Bit
7
6
5
4
3
2
1
0
Name
T1PAU
T1CK2
T1CK1
T1CK0
T1ON
T1RP2
T1RP1
T1RP0
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
T1PAU: TM1 Counter Pause Control
0: run
1: pause
The counter can be paused by setting this bit high. Clearing the bit to zero restores
normal counter operation. When in a Pause condition the TM will remain powered up
and continue to consume power. The counter will retain its residual value when this bit
changes from low to high and resume counting from this value when the bit changes
to a low value again.
Bit 6~4
T1CK2~T1CK0: Select TM1 Counter clock
000: fSYS/4
001: fSYS
010: fH/16
011: fH/64
100: fTBC
101: Undefined
110: TCK1 rising edge clock
111: TCK1 falling edge clock
These three bits are used to select the clock source for the TM. Selecting the Reserved
clock input will effectively disable the internal counter. The external pin clock source
can be chosen to be active on the rising or falling edge. The clock source fSYS is the
system clock, while fH and fTBC are other internal clocks, the details of which can be
found in the oscillator section.
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Touch Key Flash MCU with LCD/LED Driver
Bit 3
T1ON: TM1 Counter On/Off Control
0: Off
1: On
This bit controls the overall on/off function of the TM. Setting the bit high enables the
counter to run, clearing the bit disables the TM. Clearing this bit to zero will stop the
counter from counting and turn off the TM which will reduce its power consumption.
When the bit changes state from low to high the internal counter value will be reset to
zero, however when the bit changes from high to low, the internal counter will retain
its residual value until the bit returns high again.
If the TM is in the Compare Match Output Mode then the TM output pin will be reset
to its initial condition, as specified by the T1OC bit, when the T1ON bit changes from
low to high.
Bit 2~0
T1RP2~T1RP0: TM1 3-bit register, compared with the TM1 Counter bit 9~bit 7
Comparator P Match Period
000: 1024 TM1 clocks
001: 128 TM1 clocks
010: 256 TM1 clocks
011: 384 TM1 clocks
100: 512 TM1 clocks
101: 640 TM1 clocks
110: 768 TM1 clocks
111: 896 TM1 clocks
These three bits are used to setup the value on the internal CCRP 3-bit register, which
are then compared with the internal counter's highest three bits. The result of this
comparison can be selected to clear the internal counter if the T1CCLR bit is set to
zero. Setting the T1CCLR bit to zero ensures that a compare match with the CCRP
values will reset the internal counter. As the CCRP bits are only compared with the
highest three counter bits, the compare values exist in 128 clock cycle multiples.
Clearing all three bits to zero is in effect allowing the counter to overflow at its
maximum value.
• TM1C1 Register – 10-bit ETM
Bit
7
6
5
4
3
2
1
0
Name
T1AM1
T1AM0
T1AIO1
T1AIO0
T1AOC
T1APOL
T1CDN
T1CCLR
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~6
Bit 5~4
Rev. 1.40
T1AM1~T1AM0: Select TM1 CCRA Operating Mode
00: Compare Match Output Mode
01: Capture Input Mode
10: PWM Mode or Single Pulse Output Mode
11: Timer/Counter Mode
These bits setup the required operating mode for the TM. To ensure reliable operation
the TM should be switched off before any changes are made to the T1AM1 and
T1AM0 bits. In the Timer/Counter Mode, the TM output pin control must be disabled.
T1AIO1~T1AIO0: Select TP1A output function
Compare Match Output Mode
00: No change
01: Output low
10: Output high
11: Toggle output
Mode/ Single Pulse Output Mode
00: PWM output inactive state
01: PWM output active state
10: PWM output
11: Single pulse output
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March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Bit 3
Bit 2
Bit 1
Bit 0
Rev. 1.40
Capture Input Mode
00: Input capture at rising edge of TP1A
01: Input capture at falling edge of TP1A
10: Input capture at falling/rising edge of TP1A
11: Input capture disabled
Timer/counter Mode
Unused
These two bits are used to determine how the TM output pin changes state when a
certain condition is reached. The function that these bits select depends upon in which
mode the TM is running.
In the Compare Match Output Mode, the T1AIO1 and T1AIO0 bits determine how
the TM output pin changes state when a compare match occurs from the Comparator
A. The TM output pin can be setup to switch high, switch low or to toggle its present
state when a compare match occurs from the Comparator A. When the bits are both
zero, then no change will take place on the output. The initial value of the TM output
pin should be setup using the T1AOC bit in the TM1C1 register. Note that the output
level requested by the T1AIO1 and T1AIO0 bits must be different from the initial
value setup using the T1AOC bit otherwise no change will occur on the TM output pin
when a compare match occurs. After the TM output pin changes state it can be reset to
its initial level by changing the level of the T1ON bit from low to high. In the PWM
Mode, the T1AIO1 and T1AIO0 bits determine how the TM output pin changes state
when a certain compare match condition occurs. The PWM output function is modified
by changing these two bits. It is necessary to change the values of the T1AIO1 and
T1AIO0 bits only after the TM has been switched off. Unpredictable PWM outputs
will occur if the T1AIO1 and T1AIO0 bits are changed when the TM is running
T1AOC: TP1A Output control bit
Compare Match Output Mode
0: Initial low
1: Initial high
Mode/ Single Pulse Output Mode
0: Active low
1: Active high
This is the output control bit for the TM output pin. Its operation depends upon whether TM
is being used in the Compare Match Output Mode or in the PWM Mode/ Single Pulse Output
Mode. It has no effect if the TM is in the Timer/Counter Mode. In the Compare Match Output
Mode it determines the logic level of the TM output pin before a compare match occurs. In
the PWM Mode it determines if the PWM signal is active high or active low.
T1APOL: TP1A Output polarity Control
0: Non-invert
1: Invert
This bit controls the polarity of the TP1A output pin. When the bit is set high the TM
output pin will be inverted and not inverted when the bit is zero. It has no effect if the
TM is in the Timer/Counter Mode.
T1CDN: TM1 Counter count up or down flag
0: Count up
1: Count down
T1CCLR: Select TM1 Counter clear condition
0: TM1 Comparator P match
1: TM1 Comparator A match
This bit is used to select the method which clears the counter. Remember that the
Enhanced TM contains three comparators, Comparator A, Comparator B and Comparator
P, but only Comparator A or Comparator Pan be selected to clear the internal counter. With
the T1CCLR 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 T1CCLR bit
is not used in the Single Pulse or Input Capture Mode.
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BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
• TM1C2 Register – 10-bit ETM
Rev. 1.40
Bit
7
6
5
4
3
2
Name
T1BM1
T1BM0
T1BIO1
T1BIO0
T1BOC
T1BPOL
1
0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R
R/W
POR
0
0
0
0
0
0
0
0
T1PWM1 T1PWM0
Bit 7~6
T1BM1~T1BM0: Select TM1 CCRB Operating Mode
00: Compare Match Output Mode
01: Capture Input Mode
10: PWM Mode or Single Pulse Output Mode
11: Timer/Counter mode
These bits setup the required operating mode for the TM. To ensure reliable operation
the TM should be switched off before any changes are made to the T1BM1 and
T1BM0 bits. In the Timer/Counter Mode, the TM output pin control must be disabled.
Bit 5~4
T1BIO1~T1BIO0: Select TP1B_0, TP1B_1, TP1B_2 output function
Compare Match Output Mode
00: No change
01: Output low
10: Output high
11: Toggle 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 TP1B_0, TP1B_1, TP1B_2
01: Input capture at falling edge of TP1B_0, TP1B_1, TP1B_2
10: Input capture at falling/rising edge of TP1B_0, TP1B_1, TP1B_2
11: Input capture disabled
Timer/counter Mode
Unused
These two bits are used to determine how the TM output pin changes state when a
certain condition is reached. The function that these bits select depends upon in which
mode the TM is running.
In the Compare Match Output Mode, the T1BIO1 and T1BIO0 bits determine how
the TM output pin changes state when a compare match occurs from the Comparator
A. The TM output pin can be setup to switch high, switch low or to toggle its present
state when a compare match occurs from the Comparator A. When the bits are both
zero, then no change will take place on the output. The initial value of the TM output
pin should be setup using the T1BOC bit in the TM1C2 register. Note that the output
level requested by the T1BIO1 and T1BIO0 bits must be different from the initial
value setup using the T1BOC bit otherwise no change will occur on the TM output pin
when a compare match occurs. After the TM output pin changes state it can be reset to
its initial level by changing the level of the T1ON bit from low to high.
In the PWM Mode, the T1BIO1 and T1BIO0 bits determine how the TM output pin
changes state when a certain compare match condition occurs. The PWM output
function is modified by changing these two bits. It is necessary to change the values of
the T1BIO1 and T1BIO0 bits only after the TM has been switched off. Unpredictable
PWM outputs will occur if the T1BIO1 and T1BIO0 bits are changed when the TM is
running
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March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Bit 3
T1BOC: TP1B_0, TP1B_1, TP1B_2 Output control bit
Compare Match Output Mode
0: Initial low
1: Initial high
Mode/ Single Pulse Output Mode
0: Active low
1: Active high
This is the output control bit for the TM output pin. Its operation depends upon
whether TM is being used in the Compare Match Output Mode or in the PWM Mode/
Single Pulse Output Mode. It has no effect if the TM is in the Timer/Counter Mode. In
the Compare Match Output Mode it determines the logic level of the TM output pin
before a compare match occurs. In the PWM Mode it determines if the PWM signal is
active high or active low.
Bit 2
T1BPOL: TP1B_0, TP1B_1, TB1B_2 Output polarity Control
0: Non-invert
1: Invert
This bit controls the polarity of the TP1B_0, TP1B_1, TP1B_2 output pin. When the
bit is set high the TM output pin will be inverted and not inverted when the bit is zero.
It has no effect if the TM is in the Timer/Counter Mode.
Bit 1~0
T1PWM1~T1PWM0: Select PWM Mode
00: Edge aligned
01: Centre aligned, compare match on count up
10: Centre aligned, compare match on count down
11: Centre aligned, compare match on count up or down
• TM1DL Register – 10-bit ETM
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
TM1DL: TM1 Counter Low Byte Register bit 7~bit 0
TM1 10-bit Counter bit 7~bit 0
• TM1DH Register – 10-bit ETM
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
—
—
D9
D8
R/W
—
—
—
—
—
—
R
R
POR
—
—
—
—
—
—
0
0
2
1
0
Bit 7~2
Unimplemented, read as "0"
Bit 1~0
TM1DH: TM1 Counter High Byte Register bit 1~bit 0
TM1 10-bit Counter bit 9~bit 8
• TM1AL Register – 10-bit ETM
Bit
6
5
4
3
Name
D7
D6
D5
D4
D3
D2
D1
D0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~0
Rev. 1.40
7
TM1AL: TM1 Low Byte Register bit 7~bit 0
TM1 10-bit CCRA bit 7~bit 0
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March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
• TM1AH Register – 10-bit ETM
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
TM1AH: TM1 High Byte Register bit 1~bit 0
TM1 10-bit CCRA bit 9~bit 8
• TM1BL Register – 10-bit ETM
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
TM1BL: TM1 Low Byte Register bit 7~bit 0
TM1 10-bit CCRB bit 7~bit 0
• TM1BH Register – 10-bit ETM
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
TM1BH: TM1 High Byte Register bit 1~bit 0
TM1 10-bit CCRB bit 9 ~ bit 8
Enhanced Type TM Operating Modes
The Enhanced Type TM can operate in one of five operating modes, Compare Match Output Mode,
PWM Output Mode, Single Pulse Output Mode, Capture Input Mode or Timer/Counter Mode. The
operating mode is selected using the TnAM1 and TnAM0 bits in the TMnC1, and the TnBM1 and
TnBM0 bits in the TMnC2 register.
ETM Operating Mode
CCRA
CCRA
CCRA Single CCRA Input
Compare
CCRA PWM
Timer/Counter
Pulse Output
Capture
Match Output
Output Mode
Mode
Mode
Mode
Mode
CCRB Compare Match Output Mode
√
—
—
—
—
CCRB Timer/Counter Mode
—
√
—
—
—
CCRB PWM Output Mode
—
—
√
—
—
CCRB Single Pulse Output Mode
—
—
—
√
—
CCRB Input Capture Mode
—
—
—
—
—
"√": permitted; "—" : not permitted
Rev. 1.40
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March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Compare Output Mode
To select this mode, bits TnAM1, TnAM0 and TnBM1, TnBM0 in the TMnC1/TMnC2 registers
should be all cleared to zero. In this mode once the counter is enabled and running it can be cleared
by three methods. These are a counter overflow, a compare match from Comparator A and a compare
match from Comparator P. When the TnCCLR bit is low, there are two ways in which the counter
can be cleared. One is when a compare match occurs from Comparator P, the other is when the
CCRP bits are all zero which allows the counter to overflow. Here both the TnAF and TnPF interrupt
request flags for Comparator A and Comparator P respectively, will both be generated.
If the TnCCLR bit in the TMnC1 register is high then the counter will be cleared when a compare
match occurs from Comparator A. However, here only the TnAF interrupt request flag will be
generated even if the value of the CCRP bits is less than that of the CCRA registers. Therefore when
TnCCLR is high no TnPF interrupt request flag will be generated.
Counter Value
CCRP = 0
TnCCLR = 0; TnAM1, TnAM0 = 00
Counter
overflow
0x3FF
CCRP > 0
Counter cleared by CCRP value
CCRP > 0
CCRP
Pause Resume
CCRA
Counter
Reset
Stop
Time
TnON bit
TnPAU bit
TnAPOL bit
CCRP Int.
Flag TnPF
CCRA Int.
Flag TnAF
TPnA O/P Pin
Output Pin set
to Initial Level
Low if TnAOC = 0
Output Toggle
with TnAF flag
Now TnAIO1, TnAIO0 = 10
Active High Output Select
Output inverts
when TnAPOL is high
Output Pin
Reset to initial value
Output not affected by
TnAF flag. Remains High
until reset by TnON bit
Output controlled
by other pin-shared function
Here TnAIO1, TnAIO0 = 11
Toggle Output Select
ETM CCRA Compare Match Output Mode – TnCCLR = 0
Note: 1. With TnCCLR=0 a Comparator P match will clear the counter
2. The TPnA output pin is controlled only by the TnAF flag
3. The output pin is reset to its initial state by a TnON bit rising edge
Rev. 1.40
101
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
As the name of the mode suggests, after a comparison is made, the TM output pin, will change
state. The TM output pin condition however only changes state when an TnAF or TnBF interrupt
request flag is generated after a compare match occurs from Comparator A or Comparator B. The
TnPF interrupt request flag, generated from a compare match from Comparator P, will have no
effect on the TM output pin. The way in which the TM output pin changes state is determined by the
condition of the TnAIO1 and TnAIO0 bits in the TMnC1 register for ETM CCRA, and the TnBIO1
and TnBIO0 bits in the TMnC2 register for ETM CCRB. The TM output pin can be selected using
the TnAIO1, TnAIO0 bits (for the TPnA pin) and TnBIO1, TnBIO0 bits (for the TPnB_0, TPnB_1
or TPnB_2 pins) to go high, to go low or to toggle from its present condition when a compare match
occurs from Comparator A or a compare match occurs from Comparator B. The initial condition
of the TM output pin, which is setup after the TnON bit changes from low to high, is setup using
the TnAOC or TnBOC bit for TPnA or TPnB_0, TPnB_1, TPnB_2 output pins. Note that if the
TnAIO1,TnAIO0 and TnBIO1, TnBIO0 bits are zero then no pin change will take place.
Counter Value
CCRP = 0
TnCCLR = 0; TnBM1, TnBM0 = 00
Counter
overflow
0x3FF
CCRP > 0
Counter cleared by CCRP value
CCRP > 0
CCRP
Pause Resume
CCRB
Counter
Reset
Stop
Time
TnON bit
TnPAU bit
TnBPOL bit
CCRP Int.
Flag TnPF
CCRB Int.
Flag TnBAF
TPnB O/P Pin
Output Pin set
to Initial Level
Low if TnBOC = 0
Output Toggle
with TnBF flag
Now TnBIO1, TnBIO0 = 10
Active High Output Select
Output inverts
when TnBPOL is high
Output Pin
Reset to initial value
Output not affected by
TnBF flag. Remains High
until reset by TnON bit
Output controlled
by other pin-shared function
Here TnBIO1, TnBIO0 = 11
Toggle Output Select
ETM CCRB Compare Match Output Mode – TnCCLR = 0
Note: 1. With TnCCLR=0 a Comparator P match will clear the counter
2. The TPnB output pin is controlled only by the TnBF flag
3. The output pin is reset to its initial state by a TnON bit rising edge
Rev. 1.40
102
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Counter Value
CCRP = 0
TnCCLR = 0; TnAM1, TnAM0 = 00
Counter
overflow
0x3FF
CCRP > 0
Counter cleared by CCRP value
CCRP > 0
CCRP
Pause Resume
CCRA
Counter
Reset
Stop
Time
TnON bit
TnPAU bit
TnAPOL bit
CCRP Int.
Flag TnPF
CCRA Int.
Flag TnAF
TPnA O/P Pin
Output Pin set
to Initial Level
Low if TnAOC = 0
Output Toggle
with TnAF flag
Now TnAIO1, TnAIO0 = 10
Active High Output Select
Output inverts
when TnAPOL is high
Output Pin
Reset to initial value
Output not affected by
TnAF flag. Remains High
until reset by TnON bit
Output controlled
by other pin-shared function
Here TnAIO1, TnAIO0 = 11
Toggle Output Select
ETM CCRA Compare Match Output Mode – TnCCLR = 1
Note: 1. With TnCCLR=1 a Comparator A match will clear the counter
2. The TPnA output pin is controlled only by the TnAF flag
3. The TPnA output pin is reset to its initial state by a TnON bit rising edge
4. The TnPF flag is not generated when TnCCLR=1
Rev. 1.40
103
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Counter Value
CCRP = 0
TnCCLR = 0; TnBM1, TnBM0 = 00
Counter
overflow
0x3FF
CCRP > 0
Counter cleared by CCRP value
CCRP > 0
CCRP
Pause Resume
CCRB
Counter
Reset
Stop
Time
TnON bit
TnPAU bit
TnBPOL bit
CCRP Int.
Flag TnPF
CCRB Int.
Flag TnBAF
TPnB O/P Pin
Output Pin set
to Initial Level
Low if TnBOC = 0
Output Toggle
with TnBF flag
Now TnBIO1, TnBIO0 = 10
Active High Output Select
Output inverts
when TnBPOL is high
Output Pin
Reset to initial value
Output not affected by
TnBF flag. Remains High
until reset by TnON bit
Output controlled
by other pin-shared function
Here TnBIO1, TnBIO0 = 11
Toggle Output Select
ETM CCRB Compare Match Output Mode – TnCCLR = 1
Note: 1. With TnCCLR=1 a Comparator A match will clear the counter
2. The TPnB output pin is controlled only by the TnBF flag
3. The TPnB output pin is reset to its initial state by a TnON bit rising edge
4. The TnPF flag is not generated when TnCCLR=1
Rev. 1.40
104
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Timer/Counter Mode
To select this mode, bits TnAM1, TnAM0 and TnBM1, TnBM0 in the TMnC1 and TMnC2 register
should all be set high. The Timer/Counter Mode operates in an identical way to the Compare
Match Output Mode generating the same interrupt flags. The exception is that in the Timer/Counter
Mode the TM output pin is not used. Therefore the above description and Timing Diagrams for the
Compare Match Output Mode can be used to understand its function. As the TM output pin is not
used in this mode, the pin can be used as a normal I/O pin or other pin-shared function.
PWM Output Mode
To select this mode, the required bit pairs, TnAM1, TnAM0 and TnBM1, TnBM0 should be set
to 10 respectively and also the TnAIO1, TnAIO0 and TnBIO1, TnBIO0 bits should be set to 10
respectively. The PWM function within the TM is useful for applications which require functions
such as motor control, heating control, illumination control etc. By providing a signal of fixed
frequency but of varying duty cycle on the TM output pin, a square wave AC waveform can be
generated with varying equivalent DC RMS values.
As both the period and duty cycle of the PWM waveform can be controlled, the choice of generated
waveform is extremely flexible. In the PWM mode, the TnCCLR bit is used to determine in which way
the PWM period is controlled. With the TnCCLR bit set high, the PWM period can be finely controlled
using the CCRA registers. In this case the CCRB registers are used to set the PWM duty value (for
TPnB output pins). The CCRP bits are not used and TPnA output pin is not used. The PWM output can
only be generated on the TPnB output pins. With the TnCCLR bit cleared to zero, the PWM period
is set using one of the eight values of the three CCRP bits, in multiples of 128. Now both CCRA and
CCRB registers can be used to setup different duty cycle values to provide dual PWM outputs on their
relative TPnA and TPnB pins.
The TnPWM1 and TnPWM0 bits determine the PWM alignment type, which can be either edge
or centre type. In edge alignment, the leading edge of the PWM signals will all be generated
concurrently when the counter is reset to zero. With all power currents switching on at the same
time, this may give rise to problems in higher power applications. In centre alignment the centre
of the PWM active signals will occur sequentially, thus reducing the level of simultaneous power
switching currents.
Interrupt flags, one for each of the CCRA, CCRB and CCRP, will be generated when a compare match
occurs from either the Comparator A, Comparator B or Comparator P. The TnAOC and TnBOC bits in
the TMnC1 and TMnC2 register are used to select the required polarity of the PWM waveform while
the two TnAIO1, TnAIO0 and TnBIO1, TnBIO0 bits pairs are used to enable the PWM output or to
force the TM output pin to a fixed high or low level. The TnAPOL and TnBPOL bit are used to reverse
the polarity of the PWM output waveform.
Rev. 1.40
105
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
ETM, PWM Mode, Edge-aligned Mode, TnCCLR=0
CCRP
001b
010b
011b
100b
101b
110b
111b
000b
Period
128
256
384
512
640
768
896
1024
A Duty
CCRA
B Duty
CCRB
If fSYS = 16MHz, TM clock source select fSYS/4, CCRP = 100b, CCRA = 128 and CCRB = 256,
The TP1A PWM output frequency = (fSYS/4)/512 = fSYS/2048 = 7.8125kHz, duty = 128/512 = 25%.
The TP1B_n PWM output frequency = (fSYS/4)/512 = fSYS/2048 = 7.8125kHz, duty = 256/512 = 50%.
If the Duty value defined by CCRA or CCRB register is equal to or greater than the Period value,
then the PWM output duty is 100%.
ETM, PWM Mode, Edge-aligned Mode, TnCCLR=1
CCRA
1
2
3
511
512
1021
1022
1023
Period
1
2
3
511
512
1021
1022
1023
B Duty
CCRB
ETM, PWM Mode, Center-aligned Mode, TnCCLR=0
CCRP
001b
010b
011b
100b
101b
110b
111b
000b
Period
256
512
768
1024
1280
1536
1792
2046
A Duty
(CCRA×2)-1
B Duty
(CCRB×2)-1
ETM, PWM Mode, Center-aligned Mode, TnCCLR=1
CCRA
1
2
3
511
512
1021
1022
1023
Period
2
4
6
1022
1024
2042
2044
2046
B Duty
Rev. 1.40
(CCRB×2)-1
106
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Counte�
Value
TnCCLR = 0 ;
�ode Bits TnA(B)�1� TnA(B)�0 = 10
TnPW�1/TnPW�0 = 00
Counte� Clea�ed by CCRP
CCRP
Pause
CCRA
Resume
Counte� Stops
if TnON bit low
Counte� �eset w�en
TnON �etu�ns �ig�
CCRB
Time
TnON bit
TnPAU bit
TnAPOL bit
Inte��upt
still gene�ated
CCRA Int.
Flag TnAF
CCRB Int.
Flag TnBF
CCRP Int.
Flag TnPF
TnAIO1� TnAIO0 = 10 PW� Output
TnAIO1� TnAIO0 = 00
Output Ina�tive
TnAIO1� TnAIO0 = 10
TPnA Pin
TnAOC = 1
TPnB Pin
TnBOC = 1
Output Inve�ts
W�en TnAPOL = 1
TnAIO1� TnAIO0 = 10
Resume PW� Output
Duty Cy�le
set by CCRA
TPnB Pin
TnBOC = 0
Duty Cy�le
set by CCRB
PW� Pe�iod
set by CCRP
He�e TnAIO1�
TnAIO0 = 00
Output is Ina�tive
PW� �uns inte�nally
PW� �esumes
ope�ation
Output �ont�olled by
ot�e� pin-s�a�ed fun�tion
ETM PWM Mode – Edge Aligned
Note: 1. Here TnCCLR=0 therefore CCRP clears counter and determines the PWM period
2. The internal PWM function continues running even when TnAIO [1:0] (or TnBIO [1:0]) = 00 or 01
3. CCRA controls the TPnA PWM duty and CCRB controls the TPnB PWM duty
Rev. 1.40
107
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Counte�
Value
TnCCLR = 1 ;
�ode Bits TnA(B)�1� TnA(B)�0 = 10
TnPW�1/TnPW�0 = 00
Counte� Clea�ed by CCRA
CCRA
Pause
Resume
Counte� Stops
if TnON bit low
Counte� �eset w�en
TnON �etu�ns �ig�
CCRB
Time
TnON bit
TnPAU bit
TnBPOL bit
CCRA Int.
Flag TnAF
CCRB Int.
Flag TnBF
TPnB Pin
TnBOC = 1
TPnB Pin
TnBOC = 0
Duty Cy�le
set by CCRB
PW� �esumes
ope�ation
Output �ont�olled by
ot�e� pin-s�a�ed fun�tion
PW� Pe�iod
set by CCRA
Output Inve�ts
W�en TnBPOL = 1
ETM PWM Mode – Edge Aligned
Note: 1. Here TnCCLR=1 therefore CCRA clears the counter and determines the PWM period
2. The internal PWM function continues running even when TnBIO [1:0] = 00 or 01
3. The CCRA controls the TPnB PWM period and CCRB controls the TPnB PWM duty
4. Here the TM pin control register should not enable the TPnA pin as a TM output pin.
Rev. 1.40
108
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
TnCCLR = 0;
�ode Bits TnA(B)�1� TnA(B)�0 = 10
TnPW�1/TnPW�0 = 11
Counte�
Value
CCRP
Pause Resume
CCRA
Counte� Stops
if TnON bit low
Counte� �eset w�en
TnON �etu�ns �ig�
CCRB
Time
TnON bit
TnPAU bit
TnAPOL bit
CCRA Int.
Flag TnAF
CCRB Int.
Flag TnBF
CCRP Int.
Flag TnPF
TnAIO1� TnAIO0 = 10
PW� Output
TnAIO1� TnAIO0 = 10 PW� Output
TPnA Pin
TnAOC = 1
Duty Cy�le
set by CCRA
TPnB Pin
TnBOC = 0
Output Inve�ts
W�en TnAPOL = 1
TnAIO1� TnAIO0 = 00
Output Ina�tive
TPnB Pin
TnBOC = 1
Duty Cy�le
set by CCRB
PW� �esumes
ope�ation
Output �ont�olled by
ot�e� pin-s�a�ed fun�tion
PW� Pe�iod set by CCRP
ETM PWM Mode – Centre Aligned
Note: 1. Here TnCCLR=0 therefore CCRP clears the counter and determines the PWM period
2. TnPWM [1:0] =11 therefore the PWM is centre aligned
3. The internal PWM function continues running even when TnAIO [1:0] (or TnBIO [1:0]) = 00 or 01
4. CCRA controls the TPnA PWM duty and CCRB controls the TPnB PWM duty
5. CCRP will generate an interrupt request when the counter decrements to its zero value
Rev. 1.40
109
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
TnCCLR = 1;
�ode Bits TnA(B)�1� TnA(B)�0 = 10
TnPW�1/TnPW�0 = 11
Counte�
Value
CCRA
Pause
Resume
Counte� Stops
if TnON bit low
Counte� �eset w�en
TnON �etu�ns �ig�
CCRB
Time
TnON bit
TnPAU bit
TnBPOL bit
CCRB Int.
Flag TnBF
CCRA Int.
Flag TnAF
TPnB Pin
TnBOC = 1
TPnB Pin
TnBOC = 0
Duty Cy�le
set by CCRB
PW� �esumes
Output Inve�ts
ope�ation
W�en TnBPOL = 1
PW� Pe�iod
set by CCRA
Output �ont�olled by
ot�e� pin-s�a�ed fun�tion
ETM PWM Mode – Centre Aligned
Note: 1. Here TnCCLR=1 therefore CCRA clears the counter and determines the PWM period.
2. TnPWM [1:0] =11 therefore the PWM is centre aligned.
3. The internal PWM function continues running even when TnBIO [1:0] = 00 or 01.
4. CCRA controls the TPnB PWM period and CCRB controls the TPnB PWM duty.
5. CCRP will generate an interrupt request when the counter decrements to its zero value.
Rev. 1.40
110
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Single Pulse Output Mode
To select this mode, the required bit pairs, TnAM1, TnAM0 and TnBM1, TnBM0 should be set to
10 respectively and also the corresponding TnAIO1, TnAIO0 and TnBIO1, TnBIO0 bits should be
set to 11 respectively. The Single Pulse Output Mode, as the name suggests, will generate a single
shot pulse on the TM output pin.
The trigger for the pulse TPnA output leading edge is a low to high transition of the TnON bit, which
can be implemented using the application program. The trigger for the pulse TPnB output leading
edge is a compare match from Comparator B, which can be implemented using the application
program. However in the Single Pulse Mode, the TnON bit can also be made to automatically
change from low to high using the external TCKn pin, which will in turn initiate the Single Pulse
output of TPnA. When the TnON bit transitions to a high level, the counter will start running and
the pulse leading edge of TPnA will be generated. The TnON bit should remain high when the pulse
is in its active state. The generated pulse trailing edge of TPnA and TPnB will be generated when
the TnON bit is cleared to zero, which can be implemented using the application program or when a
compare match occurs from Comparator A.
However a compare match from Comparator A will also automatically clear the TnON bit and thus
generate the Single Pulse output trailing edge of TPnA and TPnB. In this way the CCRA value can
be used to control the pulse width of TPnA. The CCRA-CCRB value can be used to control the
pulse width of TPnB. A compare match from Comparator A and Comparator B will also generate
TM interrupts. The counter can only be reset back to zero when the TnON bit changes from low to
high when the counter restarts. In the Single Pulse Mode CCRP is not used. The TnCCLR bit is also
not used.

Single Pulse Generation
Rev. 1.40
111
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Counte�
Value
TnA�1� TnA�0 and TnB�1� TnB�0 = 10;
TnAIO1� TnAIO0 and TnBIO1� TnBIO0 = 11
Counte� Stopped
by CCRA
CCRA
Pause Resume
CCRB
Counte� Stops
by softwa�e
Counte� �eset
w�en TnON
�etu�ns �ig�
Time
TnON bit
TCKn pin
Auto. set
by TCKn pin
Softwa�e
T�igge�
Clea�ed by
CCRA mat��
Softwa�e
Clea�
Softwa�e
T�igge�
Softwa�e
T�igge�
TCKn pin
T�igge�
TnPAU bit
TnAPOL�
TnBPOL bit
CCRB Int.
Flag TnBF
CCRA Int.
Flag TnAF
TnAIO1� TnAIO0 and TnBIO1� TnBIO0
= 11 Single Pulse Output
TnAIO1� TnAIO0 and TnBIO1� TnBIO0
= 00 Output Ina�tive
TnAIO1� TnAIO0 and TnBIO1� TnBIO0 = 11
TPnA Pin
TnAOC = 1
TPnA Pin
TnAOC = 0
Pulse Widt�
set by CCRA
TPnB Pin
TnBOC = 1
He�e TnAIO1� TnAIO0 and
TnBIO1� TnBIO0 = 00
Output Fo��ed to Ina�tive
level but �ounte� keeps
�unning inte�nally
TnAIO1� TnAIO0 and TnBIO1� TnBIO0 = 11
Resume Single Pulse Output
Output Inve�ts
W�en TnAPOL = 1
Pulse Widt�
set by CCRA - CCRB
TPnB Pin
TnBOC = 0
Output Inve�ts
W�en TnBPOL = 1
ETM – Single Pulse Mode
Note: 1. Counter stopped by CCRA
2. CCRP is not used
3. The pulse is triggered by the TCKn pin or by setting the TnON bit high
4. A TCKn pin active edge will automatically set the TnON bit high
5. In the Single Pulse Mode, TnAIO [1:0] and TnBIO [1:0] must be set to "11" and can not be
changed.
Rev. 1.40
112
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Capture Input Mode
To select this mode bits TnAM1, TnAM0 and TnBM1, TnBM0 in the TMnC1 and TMnC2 registers
should be set to 01 respectively. This mode enables external signals to capture and store the
present value of the internal counter and can therefore be used for applications such as pulse width
measurements. The external signal is supplied on the TPnA and TPnB_0, TPnB_1, TPnB_2 pins,
whose active edge can be either a rising edge, a falling edge or both rising and falling edges; the
active edge transition type is selected using the TnAIO1, TnAIO0 and TnBIO1, TnBIO0 bits in the
TMnC1 and TMnC2 registers. The counter is started when the TnON bit changes from low to high
which is initiated using the application program.
When the required edge transition appears on the TPnA and TPnB_0, TPnB_1, TPnB_2 pins the
present value in the counter will be latched into the CCRA and CCRB registers and a TM interrupt
generated. Irrespective of what events occur on the TPnA and TPnB_0, TPnB_1, TPnB_2 pins
the counter will continue to free run until the TnON bit changes from high to low. When a CCRP
compare match occurs the counter will reset back to zero; in this way the CCRP value can be used
to control the maximum counter value. When a CCRP compare match occurs from Comparator P,
a TM interrupt will also be generated. Counting the number of overflow interrupt signals from the
CCRP can be a useful method in measuring long pulse widths. The TnAIO1, TnAIO0 and TnBIO1,
TnBIO0 bits can select the active trigger edge on the TPnA and TPnB_0, TPnB_1, TPnB_2 pins to be
a rising edge, falling edge or both edge types. If the TnAIO1, TnAIO0 and TnBIO1, TnBIO0 bits are
both set high, then no capture operation will take place irrespective of what happens on the TPnA and
TPnB_0, TPnB_1, TPnB_2 pins, however it must be noted that the counter will continue to run.
TnA�1� TnA�0 = 01
Counte�
Value
Counte�
ove�flow
CCRP
Stop
Counte�
Reset
YY
XX
Pause Resume
Time
TnON bit
TnPAU bit
T� Captu�e Pin
A�tive
edge
A�tive
edge
A�tive
edges
CCRA Int.
Flag TnAF
CCRP Int.
Flag TnPF
CCRA
Value
TnAIO1� TnAIO0
Value
XX
00 - Rising edge
YY
01 - Falling edge
XX
YY
10 - Bot� edges
11 - Disable Captu�e
ETM CCRA Capture Input Mode
Note: 1. TnAM [1:0] = 01 and active edge set by the TnAIO [1:0] bits
2. The TM Capture input pin active edge transfers he counter value to CCRA
3. TnCCLR bit not used
4. No output function -- TnAOC and TnAPOL bits not used
5. CCRP determines the counter value and the counter has a maximum count value when CCRP is
equal to zero.
Rev. 1.40
113
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
As the TPnA and TPnB_0, TPnB_1, TPnB_2 pins are pin shared with other functions, care must
be taken if the TM is in the Capture Input Mode. This is because if the pin is setup as an output,
then any transitions on this pin may cause an input capture operation to be executed. The TnCCLR,
TnAOC, TnBOC, TnAPOL and TnBPOL bits are not used in this mode.
TnB�1� TnB�0 = 01
Counte�
Value
Counte�
ove�flow
CCRP
Stop
Counte�
Reset
YY
XX
Pause Resume
Time
TnON bit
TnPAU bit
T� Captu�e Pin
A�tive
edge
A�tive
edge
A�tive
edges
CCRB Int.
Flag TnBF
CCRP Int.
Flag TnPF
CCRB
Value
TnBIO1� TnBIO0
Value
XX
00 - Rising edge
YY
01 - Falling edge
XX
YY
10 - Bot� edges
11 - Disable Captu�e
ETM CCRB Capture Input Mode
Note: 1. TnBM [1:0] = 01 and active edge set by the TnBIO [1:0] bits
2. The TM Capture input pin active edge transfers the counter value to CCRB
3. TnCCLR bit not used
4. No output function -- TnBOC and TnBPOL bits not used
5. CCRP determines the counter value and the counter has a maximum count value when CCRP is
equal to zero.
Rev. 1.40
114
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Touch Key Function
Each device provides multiple touch key functions. The touch key function is fully integrated and
requires no external components, allowing touch key functions to be implemented by the simple
manipulation of internal registers.
Touch Key Structure
The touch keys are pin shared with the PC and PD logic I/O pins, as well as having dedicated
pins. For the pin shared touch keys, the touch key function is chosen using register bits. Keys are
organised into groups of four, with each group known as a module and having a module number,
M0 to M4. Each module contains its own control logic circuits and register set. Examination of the
register names will reveal the module number it is referring to.
Device
Keys - n
BS85B12-3
12
BS85C20-3
/BS85C20-5
Touch Key
Module
Touch Key
Shared I/O Pin
M0
K1~K4
PC0~PC3
M1
K5~K8
PC4~PC7
M2
K9~K12
Dedicated Pins
M0
K1~K4
PC0~PC3
M1
K5~K8
PC4~PC7
M2
K9~K12
Dedicated Pins
M3
K13~K16
PD0~PD3
M4
K17~K20
PD4~PD7
20
Touch Key Module/Pin Reference Table
Touch Key Register Definition
Each touch key module, which contains four touch key functions, has its own suite of registers. The
following table shows the register set for each touch key module. The Mn within the register name
refers to the Touch Key module number and has a range of M0 to M4.
Name
Usage
TKMn16DH
16-bit C/F counter high byte
TKMn16DL
16-bit C/F counter low byte
TKMnC0
Control Register 0
Key Select
TKMnC1
Control Register 1
Internal reference.
Touch pad reference.
TKMnC2
Control Register 2
Counter on-off and clear control/reference clock control/TKST start bit
TKMnC3
Control Register 3
Counter overflow bits
Register Listing
Rev. 1.40
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Bit
Register
Name
7
6
5
4
3
2
1
0
TKMn16DH
D7
D6
D5
D4
D3
D2
D1
D0
TKMn16DL
D7
D6
D5
D4
D3
D2
D1
D0
TKMnC0
MnMXS1
MnMXS0
D5
D4
D3
D2
D1
D0
MnK4IO
MnK3IO
MnK2IO
MnK1IO
D1
MnROS
TKMnC1
MnK4OEN MnK3OEN MnK2OEN MnK1OEN
TKMnC2
Mn16CTON
D6
MnST
MnROEN
TKMnC3
D9
D8
MnRCOV
Mn16CTOV
MnRCCLR Mn16CTCLR
D3
MnROVS2 MnROVS1
MnROVS0
Register Content Summary
TKMn16DH 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
Module n 16-bit counter high byte contents
TKMn16DL 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
Module n 16-bit counter low byte contents
TKMnC0 Register
Bit
Name
7
6
MnMXS1 MnMXS0
5
4
3
2
1
0
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
Bits 7~6 MnMXS1, MnMXS0: Multiplexer Key Select
Bit
Bit 5~0
Rev. 1.40
Module Number
MnMXS1
MnMXS0
M0
M1
M2
M3
M4
0
0
Key 1
Key 5
Key 9
Key 13
Key 17
0
1
Key 2
Key 6
Key 10
Key 14
Key 18
1
0
Key 3
Key 7
Key 11
Key 15
Key 19
1
1
Key 4
Key 8
Key 12
Key 16
Key 20
D5~D0: These bits must be set to the binary value "011000"
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Touch Key Flash MCU with LCD/LED Driver
TKMnC1 Register
Bit
Name
7
6
5
4
3
MnK4OEN MnK3OEN MnK2OEN MnK1OEN MnK4IO
2
1
0
MnK3IO
MnK2IO
MnK1IO
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
For the BS85B12-3 n=0~2 while for the BS85C20-3 n=0~4.
Bits 7~4
MnK4OEN~ MnK1OEN: key selector control
MnK4OEN
Key 4
Key 8
M2
M3
M4
Key 12
Key 16
Key 20
Disable
1
Enable
M0
M1
M2
M3
M4
Key 3
Key 7
Key 11
Key 15
Key 19
0
Disable
1
Enable
MnK2OEN
M0
M1
M2
M3
M4
Key 2
Key 6
Key 10
Key 14
Key 18
0
Disable
1
Enable
MnK1OEN
M0
M1
M2
M3
M4
Key 1
Key 5
Key 9
Key 13
Key 17
0
Disable
1
Enable
I/O Pin or Touch Key Function Select
MnK4IO
M0
M1
PC3/Key 4
PC7/Key 8
M3
I/O pin
1
Touch Key
M0
M1
PC2/Key 3
PC6/Key 7
M3
I/O pin
1
Touch Key
M0
M1
PC1/Key 2
PC5/Key 6
M3
I/O pin
1
Touch Key
M0
M1
PC0/Key 1
PC4/Key 5
M3
M4
PD0/Key 13 PD4/Key 17
0
I/O pin
1
Touch Key
117
M4
PD1/Key 14 PD5/Key 18
0
MnK1IO
M4
PD2/Key 15 PD6/Key 19
0
MnK2IO
M4
PD3/Key 16 PD7/Key 20
0
MnK3IO
Rev. 1.40
M1
0
MnK3OEN
Bits 3~0
M0
March 12, 2015
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Touch Key Flash MCU with LCD/LED Driver
TKMnC2 Register
Bit
7
6
5
4
3
2
1
0
Name
Mn16CTON
D6
MnST
MnROEN
MnRCCLR
Mn16CTCLR
D1
MnROS
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
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Mn16CTON: 16-bit C/F counter control
0: disable
1: enable
D6: This bit must be cleared to zero.
MnST: Time slot counter start control
0: time slot counter stopped
0 → 1: enable time slot counter.
When this bit changes from low to high the time slot counter will be enabled and the
touch sense procedure started. When the time slot counter has completed its counting
an interrupt will be generated.
MnROEN: Reference clock control
0: disable
1: enable
MnRCCLR: Time slot counter clear control
0: no change
1: clear counter
This bit must be first set to 1 and then to 0.
Mn16CTCLR: 16-bit C/F counter clear control
0: no change
1: clear counter
This bit must be first set to 1 and then to 0.
D1: This bit must be cleared to zero.
MnROS: Time slot counter clock source
0: reference clock
1: sense key oscillator
M0:K4, M1:K8, M2:K12, M3:K16, M4:K20
TKMnC3 Register
Bit
7
6
Name
D7
D6
R/W
R
R
R
POR
0
0
0
Bit 7~6 Bit 5
Bit 4
Bit 3
Bit 2~0
Rev. 1.40
5
4
3
2
1
0
D3
MnROVS2
MnROVS1
MnROVS0
R/W
R/W
R/W
R/W
R/W
0
0
0
0
0
MnRCOV Mn16CTOV
D7, D6: Read only bits -- unknown values
MnRCOV: Time slot counter overflow flag
0: no overflow
1: overflow
Mn16CTOV: 16-bit C/F counter overflow flag
0: no overflow
1: overflow
D3: This bit must be cleared to zero.
MnROVS2~MnROVS0: Time slot counter overflow time setup
000: 64 count
001: 128 count
010: 256 count
011: 512 count
100: 1024 count
101: 2048 count
110: 4096 count
111: 8192 count
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Touch Key Operation
When a finger touches or is in proximity to a touch pad, the capacitance of the pad will increase.
By using this capacitance variation to change slightly the frequency of the internal sense oscillator,
touch actions can be sensed by measuring these frequency changes. Using an internal programmable
divider the reference clock is used to generated a fixed time period. By counting the number of
generated clock cycles from the sense oscillator during this fixed time period touch key actions can
be determined.
Each touch key module contains four touch key inputs which are either dedicated touch key pins or
are shared logical I/O pins. If shared, the desired function is selected using register bits. Each touch
key has its own independent sense oscillator. There are therefore four sense oscillators within each
touch key module. Each Touch Key module also has its own interrupt vector and set of interrupts
flags.
During this reference clock fixed interval, the number of clock cycles generated by the sense
oscillator is measured, and it is this value that is used to determine if a touch action has been made
or not. At the end of the fixed reference clock time interval, a Touch Key interrupt signal will be
generated.
Touch Key (1 set = Touch Key*5)
Key 0
Key 1
C/F
Key 2
&
Mux.
Key 3
Enable
M
U
X
Reference Clock
16-bit C/F
Counter
Time Slot
Counter
16-bit C/F Counter INT Flag
16-bit C/F Counter Overflow Flag
Time Slot Counter INT flag
Time Slot Counter Overflow flag
Time Slot Counter
Clock Select
Touch Switch Module Block Diagram
M n K 4 IO
I/O
E x te r n a l P in
o r T o u c h K e y
T o u c h C ir c u its
L o g ic I/O c ir c u its
M n K 3 IO
I/O
T o u c h C ir c u its
L o g ic I/O c ir c u its
b it
E x te r n a l P in
o r T o u c h K e y
T o u c h C ir c u its
L o g ic I/O c ir c u its
M n K 1 IO
I/O
b it
E x te r n a l P in
o r T o u c h K e y
M n K 2 IO
I/O
b it
E x te r n a l P in
o r T o u c h K e y
b it
T o u c h C ir c u its
L o g ic I/O c ir c u its
Touch Key or I/O Function Select
Rev. 1.40
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Touch Key Flash MCU with LCD/LED Driver
Touch Key Interrupt
Each touch key module, which consists of four touch keys, has two independent interrupts, one for
each of the, 16-bit C/F counter and time slot counter.
The time slot counter interrupt has its own interrupt vector while the 16-bit C/F counter interrupts
are contained within the Multi-function interrupts and therefore do not have their own vector. Care
must be taken during programming as the 16-bit C/F counter interrupt flags contained within the
Multi-function interrupts will not be automatically reset upon entry into the interrupt service routine
but rather must be reset manually by the application program. More details regarding the touch key
interrupts are located in the interrupt section of the datasheet.
Programming Considerations
After the relevant registers are setup, the touch key detection process is initiated the changing the
MnST bit from low to high. This will enable and synchronise all relevant oscillators. The MnRCOV
flag, which is the time slot counter flag will go high and remain high until the counter overflows.
When this happens an interrupt signal will be generated.
When the external touch key size and layout are defined, their related capacitances will then
determine the sensor oscillator frequency.
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Touch Key Flash MCU with LCD/LED Driver
Serial Interface Module – SIM
These devices contain a Serial Interface Module, which includes both the four line SPI interface or
the 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 pins are pin shared with other I/O pins and must be selected using
the 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.
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, but this device provided only one SCS pin. If the master needs to control
multiple slave devices from a single master, the master can use I/O pin to select the slave devices.
SPI Interface Operation
The SPI interface is a full duplex synchronous serial data link. It is a four line interface with pin
names SDI, SDO, SCK and SCS. Pins SDI and SDO are the Serial Data Input and Serial Data
Output lines, SCK is the Serial Clock line and SCS is the Slave Select line. As the SPI interface
pins are pin-shared with normal I/O pins and with the I2C function pins, the SPI interface must first
be enabled by setting the correct bits in the SIMC0 and SIMC2 registers. 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
as I/O function.
SPI Master/Slave Connection
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
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.
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Touch Key Flash MCU with LCD/LED Driver

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
3
2
1
0
SIMC0
SIM2
SIM1
SIM0
PCKEN
PCKP1
PCKP0
SIMEN
—
SIMD
D7
D6
D5
D4
D3
D2
D1
D0
SIMC2
D7
D6
CKPOLB
CKEG
MLS
CSEN
WCOL
TRF
SPI Register List
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
There are also two control registers for the SPI interface, SIMC0 and SIMC2. Note that the SIMC2
register also has the name SIMA which is used by the I2C function. The SIMC1 register is not used
by the SPI function, only by the I2C function. Register SIMC0 is used to control the enable/disable
function and to set the data transmission clock frequency. Although not connected with the SPI
function, the SIMC0 register is also used to control the Peripheral Clock Prescaler. Register SIMC2
is used for other control functions such as LSB/MSB selection, write collision flag etc.
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SIMC0 Register
Rev. 1.40
Bit
7
6
5
4
3
2
1
0
Name
SIM2
SIM1
SIM0
PCKEN
PCKP1
PCKP0
SIMEN
—
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
—
POR
1
1
1
0
0
0
0
—
Bit 7~5
SIM2, SIM1, 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 fLIRC
100: Unused
101: SPI slave mode
110: I2C slave mode
111: Unused
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 the TM0. If the SPI Slave Mode is selected then
the clock will be supplied by an external Master device.
Bit 4
PCKEN: PCK Output Pin Control
0: Disable
1: Enable
Bit 3~2
PCKP1, PCKP0: Select PCK output pin frequency
00: fSYS
01: fSYS/4
10: fSYS/8
11: TM0 CCRP match frequency/2
Bit 1
SIMEN: SIM Control
0: disable
1: enable
The bit is the overall on/off control for the SIM interface. When the SIMEN bit is
cleared, the SDI, SDO, SCK and SCS, or SDA and SCL lines will be as I/O function
and the SIM operating current will be reduced to a minimum value. When the bit
is high the SIM interface is enabled. If the SIM is configured to operate as an SPI
interface via the SIM2~SIM0 bits, the contents of the SPI control registers will remain
at the previous settings when the SIMEN bit changes from low to high and should
therefore be first initialised by the application program. If the SIM is configured to
operate as an I2C interface via the SIM2~SIM0 bits and the SIMEN bit changes from
low to high, the contents of the I2C control bits such as HTX and TXAK will remain
at the previous settings and should therefore be first initialised by the application
program while the relevant I2C flags such as HCF, HAAS, HBB, SRW and RXAK will
be set to their default states.
Bit 0
unimplemented, read as "0"
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SIMC2 Register
Rev. 1.40
Bit
7
6
5
4
3
2
1
0
Name
D7
D6
CKPOLB
CKEG
MLS
CSEN
WCOL
TRF
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~6
Undefined bit
This bit can be read or written by user software program.
Bit 5
CKPOLB: Determines the base condition of the clock line
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: Determines SPI SCK active clock edge type
CKPOLB=0
0: SCK is high base level and data capture at SCK rising edge
1: SCK is high base level and data capture at SCK falling edge
CKPOLB=1
0: SCK is low base level and data capture at SCK falling edge
1: SCK is low base level and data capture at SCK rising edge
The CKEG and CKPOLB bits are used to setup the way that the clock signal outputs
and inputs data on the SPI bus. These two bits must be configured before data transfer
is executed otherwise an erroneous clock edge may be generated. The CKPOLB bit
determines the base condition of the clock line, if the bit is high, then the SCK line
will be low when the clock is inactive. When the CKPOLB bit is low, then the SCK
line will be high when the clock is inactive. The CKEG bit determines active clock
edge type which depends upon the condition of CKPOLB bit.
Bit 3
MLS: SPI Data shift order
0: LSB
1: MSB
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 as I/O function. 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 if a data collision has occurred. 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.
The bit can be cleared by the application program.
Bit 0
TRF: SPI Transmit/Receive Complete flag
0: Data is being transferred
1: SPI data transmission is completed
The TRF bit is the Transmit/Receive Complete flag and is set "1" automatically when
an SPI data transmission is completed, but must set to "0" by the application program.
It can be used to generate an interrupt.
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SPI Communication
After the SPI interface is enabled by setting the SIMEN bit high, then in the Master Mode, when
data is written to the SIMD register, transmission/reception will begin simultaneously. When the data
transfer is complete, the TRF flag will be set automatically, but must be cleared using the application
program. In the Slave Mode, when the clock signal from the master has been received, any data in
the SIMD register will be transmitted and any data on the SDI pin will be shifted into the SIMD
register. The master should output an SCS signal to enable the slave device before a clock signal
is provided. The slave data to be transferred should be well prepared at the appropriate moment
relative to the SCS signal depending upon the configurations of the CKPOLB bit and CKEG bit.
The accompanying timing diagram shows the relationship between the slave data and SCS signal for
various configurations of the CKPOLB and CKEG bits.
The SPI will continue to function even in the IDLE Mode.

SPI Master Mode Timing
SPI Slave Mode Timing CKEG=0
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SPI Slave Mode Timing CKEG=1

SPI Transfer Control Flowchart
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Touch Key Flash MCU with LCD/LED Driver
I2C Interface
The I 2C interface is used to communicate with external peripheral devices such as sensors,
EEPROM memory etc. Originally developed by Philips, it is a two line low speed serial interface
for synchronous serial data transfer. The advantage of only two lines for communication, relatively
simple communication protocol and the ability to accommodate multiple devices on the same bus
has made it an extremely popular interface type for many applications.
I2C Master Slave Bus Connection
I2C Interface Operation
The I2C serial interface is a two line interface, a serial data line, SDA, and serial clock line, SCL. As
many devices may be connected together on the same bus, their outputs are both open drain types.
For this reason it is necessary that external pull-high resistors are connected to these outputs. Note
that no chip select line exists, as each device on the I2C bus is identified by a unique address which
will be transmitted and received on the I2C bus.
When two devices communicate with each other on the bidirectional I2C bus, one is known as the
master device and one as the slave device. Both master and slave can transmit and receive data,
however, it is the master device that has overall control of the bus. For these devices, which only
operates in slave mode, there are two methods of transferring data on the I2C bus, the slave transmit
mode and the slave receive mode.

I2C Block Diagram
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Touch Key Flash MCU with LCD/LED Driver
The debounce time of the I2C interface 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, is 2 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)
fSYS > 4MHz
fSYS > 10MHz
2 system clock debounce
I2C Minimum fSYS Frequency
S T A R T s ig n a l
fro m M a s te r
S e n d s la v e a d d r e s s
a n d R /W b it fr o m M a s te r
A c k n o w le d g e
fr o m s la v e
S e n d d a ta b y te
fro m M a s te r
A c k n o w le d g e
fr o m s la v e
S T O P s ig n a l
fro m M a s te r
I2C Registers
There are four control registers associated with the I2C bus, SIMC0, SIMC1, SIMA and I2CTOC
and one data register, SIMD. The SIMD register, which is shown in the above SPI section, is used to
store the data being transmitted and received on the I2C bus. Before the microcontroller writes data
to the I2C bus, the actual data to be transmitted must be placed in the SIMD register. After the data is
received from the I2C bus, the microcontroller can read it from the SIMD register. Any transmission
or reception of data from the I2C bus must be made via the SIMD register. The SIM pins are pin
shared with other I/O pins and must be selected using the SIMEN bit in the SIMC0 register.
Note that the SIMA register also has the name SIMC2 which is used by the SPI function. Bit SIMEN
and bits SIM2~SIM0 in register SIMC0 are used by the I2C interface.
Bit
Register
Name
7
6
5
4
3
2
1
0
SIMC0
SIM2
SIM1
SIM0
PCKEN
PCKP1
PCKP0
SIMEN
—
SIMC1
HCF
HAAS
HBB
HTX
TXAK
SRW
IAMWU
RXAK
SIMD
D7
D6
D5
D4
D3
D2
D1
D0
SIMA
IICA6
IICA5
IICA4
IICA3
IICA2
IICA1
IICA0
D0
I2CTOC
I2CTOEN
I2CTOF
I2CTOS5 I2CTOS4 I2CTOS3 I2CTOS2 I2CTOS1 I2CTOS0
I2C Register List
Rev. 1.40
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Touch Key Flash MCU with LCD/LED Driver
SIMC0 Register
Rev. 1.40
Bit
7
6
5
4
3
2
1
0
Name
SIM2
SIM1
SIM0
PCKEN
PCKP1
PCKP0
SIMEN
—
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
—
POR
1
1
1
0
0
0
0
—
Bit 7~5
SIM2, SIM1, 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 fLIRC
100: SPI master mode; SPI clock is TM0 CCRP match frequency/2
101: SPI slave mode
110: I2C slave mode
111: Unused mode
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 the TM0. If the SPI Slave Mode is selected then
the clock will be supplied by an external Master device.
Bit 4
PCKEN: PCK Output Pin Control
Described elsewhere
Bit 3~2
PCKP1, PCKP0: Select PCK output pin frequency
Described elsewhere
Bit 1
SIMEN: SIM Control
0: disable
1: enable
The bit is the overall on/off control for the SIM interface. When the SIMEN bit is
cleared, the SDI, SDO, SCK and SCS, or SDA and SCL lines will be as I/O function
and the SIM operating current will be reduced to a minimum value. When the bit
is high the SIM interface is enabled. If the SIM is configured to operate as an SPI
interface via the SIM2~SIM0 bits, the contents of the SPI control registers will remain
at the previous settings when the SIMEN bit changes from low to high and should
therefore be first initialised by the application program. If the SIM is configured to
operate as an I2C interface via the SIM2~SIM0 bits and the SIMEN bit changes from
low to high, the contents of the I2C control bits such as HTX and TXAK will remain
at the previous settings and should therefore be first initialised by the application
program while the relevant I2C flags such as HCF, HAAS, HBB, SRW and RXAK will
be set to their default states.
Bit 0
unimplemented, read as "0"
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SIMC1 Register
Rev. 1.40
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
R/W
R
POR
1
0
0
0
0
0
0
1
Bit 7
HCF: I2C 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.
Bit 6
HAAS: I2C Bus address match flag
0: Not address match
1: Address match
The HASS 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: Select I2C slave device is transmitter or receiver
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 do not send acknowledge flag
The TXAK bit is the transmit acknowledge flag. After the slave device receipt of 8-bits
of data, this bit will be transmitted to the bus on the 9th clock from the slave device.
The slave device must always set TXAK bit to "0" before further data is received.
Bit 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 I2C address match wake-up from SLEEP or
IDLE Mode. If the IAMWU bit has been set before entering either the SLEEP or
IDLE mode to enable the I2C baddress match wake up, then this bit must be cleared by
the application program after wake-up to ensure correction device operation.
Bit 0
RXAK: I2C Bus Receive acknowledge flag
0: Slave receive acknowledge flag
1: Slave do not receive acknowledge flag
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Touch Key Flash MCU with LCD/LED Driver
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.
I2CTOC Register
Bit
7
6
Name
I2CTOEN
I2CTOF
5
4
3
2
1
0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
I2CTOS5 I2CTOS4 I2CTOS3 I2CTOS2 I2CTOS1 I2CTOS0
Bit 7
I2CTOEN: I2C Time-out Control
0: disable
1: enable
Bit 6
I2CTOF: Time-out flag
0: no time-out
1: time-out occurred
Bit 5~0
I2CTOS5~I2CTOS0: Time-Out Time Definition
I2C time-out clock source is fLIRC/32.
I2C Time-Out time is given by: [I2CTOS5 : I2CTOS0]+1) x (32/fLIRC)
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
SIMA Register
Bit
7
6
5
4
3
2
1
0
Name
IICA6
IICA5
IICA4
IICA3
IICA2
IICA1
IICA0
D0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
x
x
x
x
x
x
x
x
”x“ unknown
Rev. 1.40
Bit 7~1
IICA6~ IICA0: I2C slave address
IICA6~ IICA0 is the I2C slave address bit 6~bit 0.
The SIMA register is also used by the SPI interface but has the name SIMC2. The
SIMA register is the location where the 7-bit slave address of the slave device is stored.
Bits 7~1 of the SIMA register define the device slave address. Bit 0 is not defined.
When a master device, which is connected to the I2C bus, sends out an address, which
matches the slave address in the SIMA register, the slave device will be selected. Note
that the SIMA register is the same register address as SIMC2 which is used by the SPI
interface.
Bit 0
Undefined bit
This bit can be read or written by user software program.
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Touch Key Flash MCU with LCD/LED Driver
I2C Bus Communication
Communication on the I2C bus requires four separate steps, a START signal, a slave device address
transmission, a data transmission and finally a STOP signal. When a START signal is placed on
the I2C bus, all devices on the bus will receive this signal and be notified of the imminent arrival of
data on the bus. The first seven bits of the data will be the slave address with the first bit being the
MSB. If the address of the slave device matches that of the transmitted address, the HAAS bit in the
SIMC1 register will be set and an I2C interrupt will be generated. After entering the interrupt service
routine, the slave device must first check the condition of the HAAS bit to determine whether the
interrupt source originates from an address match or from the completion of an 8-bit data transfer.
During a data transfer, note that after the 7-bit slave address has been transmitted, the following bit,
which is the 8th bit, is the read/write bit whose value will be placed in the 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 and SIMEN bits in the SIMC0 register to "1" 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 and SIM Muti-Function interrupt enable bit of the interrupt control register to enable
the SIM interrupt and Multi-function interrupt.

I2C Bus Initialisation Flow Chart
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.
Rev. 1.40
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Touch Key Flash MCU with LCD/LED Driver

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.
I2C Communication Timing Diagram
Slave Address
The transmission of a START signal by the master will be detected by all devices on the I2C bus.
To determine which slave device the master wishes to communicate with, the address of the slave
device will be sent out immediately following the START signal. All slave devices, after receiving
this 7-bit address data, will compare it with their own 7-bit slave address. If the address sent out by
the master matches the internal address of the microcontroller slave device, then an internal I2C bus
interrupt signal will be generated. The next bit following the address, which is the 8th bit, defines
the read/write status and will be saved to the SRW bit of the SIMC1 register. The slave device will
then transmit an acknowledge bit, which is a low level, as the 9th bit. The slave device will also set
the status flag HAAS when the addresses match.
As an I 2C bus interrupt can come from two sources, when the program enters the interrupt
subroutine, the HAAS bit should be examined to see whether the interrupt source has come from
a matching slave address or from the completion of a data byte transfer. When a slave address is
matched, the 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 slave device wishes to read data from the
I2C bus or write data to the I2C bus. The slave device should examine this bit to determine if it is to
be a transmitter or a receiver. If the 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.
Rev. 1.40
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Touch Key Flash MCU with LCD/LED Driver
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".
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.
I2C Bus ISR Flow Chart
Rev. 1.40
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Touch Key Flash MCU with LCD/LED Driver
I2C Time-out Control
In order to reduce the problem of I2C lockup due to reception of erroneous clock sources, clock, a
time-out function is provided. If the clock source to the I2C is not received then after a fixed time
period, the I2C circuitry and registers will be reset.
The time-out counter starts counting 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 setup by the I2CTOC register, then a time-out condition will occur. The
time-out function will stop when an I2C "STOP" condition occurs.
S C L
S ta rt
S R W
S la v e A d d r e s s
0
1
S D A
1
1
0
1
0
A C K
1
0
I2 C t i m e - o u t
c o u n te r s ta rt
S to p
S C L
1
0
0
1
0
1
0
0
S D A
I2 C t im e - o u t c o u n t e r r e s e t
o n S C L n e g a tiv e tr a n s itio n
I2C Time-out
When an I2C time-out counter overflow occurs, the counter will stop and the I2CTOEN bit will be
cleared to zero and the I2CTF bit will be set high to indicate that a time-out condition as occurred.
The time-out condition will also generate an interrupt which uses the I2C interrrupt vector. When
an I2C time-out occurs the I2C internal circuitry will be reset and the registers will be reset into the
following condition:
Register
After I2C Time-out
SIMDR, SIMAR, SIMC0
No change
SIMC1
Reset to POR condition
I2C Registers After Time-out
The I2CTOF flag can be cleared by the application program. There are 64 time-out periods which
can be selected using bits in the I2CTOC register. The time-out time is given by the formula:
((1~64)×32)/fLIRC. This gives a range of about 1ms to 64ms. Note also that the LIRC oscillator is
continuously enabled.
Rev. 1.40
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Touch Key Flash MCU with LCD/LED Driver
Peripheral Clock Output
The Peripheral Clock Output allows the device to supply external hardware with a clock signal
synchronised to the microcontroller clock.
Peripheral Clock Operation
As the peripheral clock output pin, PCK, is shared with I/O line, the required pin function is chosen
via PCKEN in the SIMC0 register. The Peripheral Clock function is controlled using the SIMC0
register. The clock source for the Peripheral Clock Output can originate from either the TM0 CCRP
match frequency/2 or a divided ratio of the internal fSYS clock. The PCKEN bit in the SIMC0 register
is the overall on/off control, setting PCKEN bit to "1" enables the Peripheral Clock, setting PCKEN
bit to "0" disables it. The required division ratio of the system clock is selected using the PCKP1
and PCKP0 bits in the same register. If the device enters the SLEEP Mode this will disable the
Peripheral Clock output.
SIMC0 Register
Rev. 1.40
Bit
7
6
5
4
Name
SIM2
SIM1
SIM0
PCKEN
3
R/W
R/W
R/W
R/W
R/W
R/W
POR
1
1
1
0
0
2
1
0
SIMEN
—
R/W
R/W
—
0
0
—
PCKPSC1 PCKPSC0
Bit 7~5
SIM2~SIM0: SIM Operating Mode Control
Described elsewhere
Bit 4
PCKEN: PCK Output Pin Control
0: disable
1: enable
Bit 3~2
PCKPSC1, PCKPSC0: Select PCK output pin frequency
0: fSYS
1: fSYS/4
2: fSYS/8
3: TM0 CCRP match frequency/2
Bit 1
SIMEN: SIM Control
Described elsewhere
Bit 0
Unimplemented, read as "0"
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Touch Key Flash MCU with LCD/LED Driver
Interrupts
Interrupts are an important part of any microcontroller system. When an external event or an
internal function such as a Touch Action or Timer Module requires microcontroller attention, their
corresponding interrupt will enforce a temporary suspension of the main program allowing the
microcontroller to direct attention to their respective needs. The devices contains several external
interrupt and internal interrupts functions. The external interrupt is generated by the action of the
external INT pin, while the internal interrupts are generated by various internal functions such as the
Touch Keys, Timer Module, Time Base, SIM etc.
Interrupt Registers
Overall interrupt control, which basically means the setting of request flags when certain
microcontroller conditions occur and the setting of interrupt enable bits by the application program,
is controlled by a series of registers, located in the Special Purpose Data Memory, as shown in the
accompanying table. The number of registers depends upon the device chosen but fall into three
categories. The first is the INTC0~INTC3 registers which setup the primary interrupts, the
second is the MFI0~MFI5 registers which setup the Multi-function interrupts. Finally there is an
INTEG register to setup the external interrupt trigger edge type.
Each register contains a number of enable bits to enable or disable individual registers as well as
interrupt flags to indicate the presence of an interrupt request. The naming convention of these
follows a specific pattern. First is listed an abbreviated interrupt type, then the (optional) number of
that interrupt followed by either an E for enable/disable bit or F for request flag.
Function
Enable Bit
Request Flag
Notes
Global
EMI
—
—
INT Pin
INTnE
INTnF
N=0 or 1
Touch Key Module
TKMnE
TKMnF
n=0~4
SIM
SIM
SIF
—
EEPROM
DEE
DEF
—
Multi-function
MFnE
MFnF
n=0~5
Time Base
TBnE
TBnF
N=0 or 1
LVD
LVF
LVE
—
External Peripheral
TM
XPE
XPF
—
TnPE
TnPF
n=0~2
TnAE
TnAF
n=0~2
TnBE
TnBF
n=1
Interrupt Register Bit Naming Conventions
Rev. 1.40
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Touch Key Flash MCU with LCD/LED Driver
Interrupt Register Contents
BS85B12-3
Name
INTEG
Bit
7
6
5
4
3
2
1
0
—
—
—
—
INT1S1
INT1S0
INT0S1
INT0S0
INTC0
—
SIMF
INT1F
INT0F
SIME
INT1E
INT0E
EMI
INTC1
TB0F
TKM2F
TKM1F
TKM0F
TB0E
TKM2E
TKM1E
TKM0E
INTC2
MF3F
MF2F
MF1F
MF0F
MF3E
MF2E
MF1E
MF0E
MFI0
M116CTF
D6
M016CTF
D4
M116CTE
D2
M016CTE
D0
MFI1
T0AF
T0PF
M216CTF
D4
T0AE
T0PE
M216CTE
D0
MFI2
—
T1BF
T1AF
T1PF
—
T1BE
T1AE
T1PE
MFI3
DEF
LVF
XPF
TB1F
DEE
LVE
XPE
TB1E
7
6
5
4
3
2
1
0
—
—
—
—
INT1S1
INT1S0
INT0S1
INT0S0
BS85C20-3/BS85C20-5
Name
INTEG
Bit
INTC0
—
SIMF
INT1F
INT0F
SIME
INT1E
INT0E
EMI
INTC1
TB0F
TKM2F
TKM1F
TKM0F
TB0E
TKM2E
TKM1E
TKM0E
INTC2
MF3F
MF2F
MF1F
MF0F
MF3E
MF2E
MF1E
MF0E
INTC3
MF5F
MF4F
TKM4F
TKM3F
MF5E
MF4E
TKM4E
TKM3E
MFI0
M116CTF
D6
M016CTF
D4
M116CTE
D2
M016CTE
D0
MFI1
T0AF
T0PF
M216CTF
D4
T0AE
T0PE
M216CTE
D0
MFI2
—
T1BF
T1AF
T1PF
—
T1BE
T1AE
T1PE
MFI3
DEF
LVF
XPF
TB1F
DEE
LVE
XPE
TB1E
MFI4
M416CTF
D6
M316CTF
D4
M416CTE
D2
M316CTE
D0
MFI5
—
—
T2AF
T2PF
—
—
T2AE
T2PE
INTEG Register – All devices
Rev. 1.40
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
INT1S1
INT1S0
INT0S1
INT0S0
R/W
—
—
—
—
R/W
R/W
R/W
R/W
POR
—
—
—
—
0
0
0
0
Bit 7~2
unimplemented, read as "0"
Bit 1~0
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
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Touch Key Flash MCU with LCD/LED Driver
INTC0 Register – All devices
Bit
7
6
5
4
3
2
1
0
Name
—
SIMF
INT1F
INT0F
SIME
INT1E
INT0E
EMI
R/W
—
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
—
0
0
0
0
0
0
0
Bit 7
Bit 6 Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
unimplemented, read as "0"
SIMF: SIM interrupt request flag
0: no request
1: interrupt request
INT1F: INT1 pin interrupt request flag
0: no request
1: interrupt request
INT0F: INT0 pin interrupt request flag
0: No request
1: Interrupt request
SIME: SIM interrupt control
0: disable
1: enable
INT1E: INT1 pin interrupt control
0: disable
1: enable
INT0E: INT0 pin interrupt control
0: disable
1: enable
EMI: Global interrupt control
0: disable
1: enable
INTC1 Register – All devices
Bit
7
6
5
4
3
2
1
0
Name
TB0F
TKM2F
TKM1F
TKM0F
TB0E
TKM2E
TKM1E
TKM0E
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
0
0
0
0
0
0
0
0
POR
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Rev. 1.40
TB0F: Time Base 0 interrupt request flag
0: no request
1: interrupt request
TKM2F: Touch Key Module 2 interrupt request flag
0: no request
1: interrupt request
TKM1F: Touch Key Module 1 interrupt request flag
0: no request
1: interrupt request
TKM0F: Touch Key Module 0 interrupt request flag
0: no request
1: interrupt request
TB0E: Time Base 0 interrupt control
0: disable
1: enable
TKM2E: Touch Key Module 2 interrupt control
0: disable
1: enable
TKM1E: Touch Key Module 1 interrupt control
0: disable
1: enable
TKM0E: Touch Key Module 0 interrupt control
0: disable
1: enable
139
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Touch Key Flash MCU with LCD/LED Driver
INTC2 Register – All devices
Bit
7
6
5
4
3
2
1
0
Name
MF3F
MF2F
MF1F
MF0F
MF3E
MF2E
MF1E
MF0E
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
MF3F: Multi-function interrupt 3 request flag
0: no request
1: interrupt request
MF2F: Multi-function interrupt 2 request flag
0: no request
1: interrupt request
MF1F: Multi-function interrupt 1 request flag
0: no request
1: interrupt request
MF0F: Multi-function interrupt 0 request flag
0: no request
1: interrupt request
MF3E: Multi-function interrupt 3 control
0: disable
1: enable
MF2E: Multi-function interrupt 2 control
0: disable
1: enable
MF1E: Multi-function interrupt 1 control
0: disable
1: enable
MF0E: Multi-function interrupt 0 control
0: disable
1: enable
INTC3 Register – BS85C20-3/BS85C20-5 only
Bit
7
6
5
4
3
2
1
0
Name
MF5F
MF4F
TKM4F
TKM3F
MF5E
MF4E
TKM4E
TKM3E
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
0
0
0
0
0
0
0
0
POR
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
bit 0
Rev. 1.40
MF5F: Multi-function interrupt 5 request flag
0: no request
1: interrupt request
MF4F: Multi-function interrupt 4 request flag
0: no request
1: interrupt request
TKM4F: Touch Key Module 4 interrupt request flag
0: no request
1: interrupt request
TKM3F: Touch Key Module 3 interrupt request flag
0: no request
1: interrupt request
MF5E: Multi-function interrupt 5 control
0: disable
1: enable
MF4E: Multi-function interrupt 4 control
0: disable
1: enable
TKM4E: Touch Key Module 4 interrupt control
0: disable
1: enable
TKM3E: Touch Key Module 3 interrupt control
0: disable
1: enable
140
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Touch Key Flash MCU with LCD/LED Driver
MFI0 Register – All devices
Bit
7
6
5
4
3
2
1
0
Name
M116CTF
D6
M016CTF
D4
M116CTE
D2
M016CTE
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 M116CTF: Touch Key Module 1 16-bit counter interrupt request flag
0: no request
1: interrupt request
Bit 6
D6: This bit must be cleared to zero
Bit 5 M016CTF: Touch Key Module 0 16-bit counter interrupt request flag
0: no request
1: interrupt request
Bit 4
D4: This bit must be cleared to zero
Bit 3
M116CTE: Touch Key Module 1 16-bit timer interrupt control
0: disable
1: enable
Bit 2
D2: This bit must be cleared to zero
Bit 1
M016CTE: Touch Key Module 0 16-bit timer interrupt control
0: disable
1: enable
Bit 0
D0: This bit must be cleared to zero
MFI1 Register – All devices
Rev. 1.40
Bit
7
6
5
4
3
2
1
0
Name
T0AF
T0PF
M216CTF
D4
T0AE
T0PE
M216CTE
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
T0AF: TM0 Comparator A match interrupt request flag
0: no request
1: interrupt request
Bit 6
T0PF: TM0 Comparator P match interrupt request flag
0: no request
1: interrupt request
Bit 5
M216CTF: Touch Key Module 2 16-bit counter interrupt request flag
0: no request
1: interrupt request
Bit 4
D4: This bit must be cleared to zero
Bit 3
T0AE: TM0 Comparator A match interrupt control
0: disable
1: enable
Bit 2
T0PE: TM0 Comparator P match interrupt control
0: disable
1: enable
Bit 1
M216CTE: Touch Key Module 2 16-bit counter interrupt control
0: disable
1: enable
Bit 0
D0: This bit must be cleared to zero
141
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Touch Key Flash MCU with LCD/LED Driver
MFI2 Register – All devices
Bit
7
6
5
4
3
2
1
0
Name
—
T1BF
T1AF
T1PF
—
T1BE
T1AE
T1PE
R/W
—
R/W
R/W
R/W
—
R/W
R/W
R/W
POR
—
0
0
0
—
0
0
0
Bit 7 Bit 6
Bit 5 Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
unimplemented, read as "0"
T1BF: TM1 Comparator B match interrupt request flag
0: no request
1: interrupt request
T1AF: TM1 Comparator A match interrupt request flag
0: no request
1: interrupt request
T1PF: TM1 Comparator P match interrupt request flag
0: no request
1: interrupt request
unimplemented, read as "0"
T1BE: TM1 Comparator B match interrupt control
0: disable
1: enable
T1AE: TM1 Comparator A match interrupt control
0: disable
1: enable
T1PE: TM1 Comparator P match interrupt control
0: disable
1: enable
MFI3 Register – All devices
Bit
7
6
5
4
3
2
1
0
Name
DEF
LVF
XPF
TB1F
DEE
LVE
XPE
TB1E
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
0
0
0
0
0
0
0
0
POR
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Rev. 1.40
DEF: Data EEPROM interrupt request flag
0: no request
1: interrupt request
LVF: LVD interrupt request flag
0: no request
1: interrupt request
XPF: External peripheral interrupt request flag
0: no request
1: interrupt request
TB1F: Time Base 1 interrupt request flag
0: no request
1: interrupt request
DEE: Data EEPROM interrupt control
0: disable
1: enable
LVE: LVD interrupt control
0: disable
1: enable
XPE: External Peripheral interrupt control
0: disable
1: enable
TB1E: Time Base 1 interrupt control
0: disable
1: enable
142
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Touch Key Flash MCU with LCD/LED Driver
MFI4 Register – BS85C20-3/BS85C20-5 only
Bit
7
6
5
4
3
2
1
0
Name
M416CTF
D6
M316CTF
D4
M416CTE
D2
M316CTE
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
M416CTF: Touch Key Module 4 16-bit counter interrupt request flag
0: no request
1: interrupt request
Bit 6
D6: This bit must be cleared to zero
Bit 5
M316CTF: Touch Key Module 3 16-bit counter interrupt request flag
0: no request
1: interrupt request
Bit 4
D4: This bit must be cleared to zero
Bit 3
M416CTE: Touch Key Module 4 16-bit counter interrupt control
0: disable
1: enable
Bit 2
D2: This bit must be cleared to zero
Bit 1
M316CTE: Touch Key Module 3 16-bit counter interrupt control
0: disable
1: enable
Bit 0
D0: This bit must be cleared to zero
MFI5 Register – BS85C20-3/BS85C20-5 only
Rev. 1.40
Bit
7
6
5
4
3
2
1
0
Name
—
—
T2AF
T2PF
—
—
T2AE
T2PE
R/W
—
—
R/W
R/W
—
—
R/W
R/W
POR
—
—
0
0
—
—
0
0
Bit 7~6
unimplemented, read as "0"
Bit 5
T2AF: TM2 Comparator A match interrupt request flag
0: no request
1: interrupt request
Bit 4
T2PF: TM2 Comparator P match interrupt request flag
0: no request
1: interrupt request
Bit 3~2
unimplemented, read as "0"
Bit 1
T2AE: TM2 Comparator A match interrupt control
0: disable
1: enable
Bit 0
T2PE: TM2 Comparator P match interrupt control
0: disable
1: enable
143
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Interrupt Operation
When the conditions for an interrupt event occur, such as a Touch Key Counter overflow, Timer
Module overflow, 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 instruction 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 instruction, which retrieves the original Program Counter
address from the stack and allows the microcontroller to continue with normal execution at the point
where the interrupt occurred.
The various interrupt enable bits, together with their associated request flags, are shown in the
accompanying diagrams with their order of priority. Some interrupt sources have their own
individual vector while others share the same multi-function interrupt vector. Once an interrupt
subroutine is serviced, all the other interrupts will be blocked, as the global interrupt enable bit,
EMI bit will be cleared automatically. This will prevent any further interrupt nesting from occurring.
However, if other interrupt requests occur during this interval, although the interrupt will not be
immediately serviced, the request flag will still be recorded.
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 enters the SLEEP or IDLE Mode.
Rev. 1.40
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Touch Key Flash MCU with LCD/LED Driver

Interrupt Structure
Rev. 1.40
145
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Touch Key Flash MCU with LCD/LED Driver
External Interrupt
The external interrupt is controlled by signal transitions on the INT0 and INT1 pins. An external
interrupt request will take place when the external interrupt request flag, INT0F or INT1F, is set,
which will occur when a transition, whose type is chosen by the edge select bits, appears on the
external interrupt pin. To allow the program to branch to its respective interrupt vector address, the
global interrupt enable bit, EMI, and respective external interrupt enable bit, INT0E or 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
pin is pin-shared with I/O pin, it can only be configured as external interrupt pin if the external
interrupt enable bit in the corresponding interrupt register has been set. The pin must also be setup as
an input by setting the corresponding bit in the port control register. When the interrupt is enabled,
the stack is not full and the correct transition type appears on the external interrupt pin, a subroutine
call to the external interrupt vector, will take place. When the interrupt is serviced, the external
interrupt request flag, INTF, 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 pin
will remain valid even if the pin is used as an external interrupt input.
The INTEG register is used to select the type of active edge that will trigger the external interrupt.
A choice of either rising or falling or both edge types can be chosen to trigger an external interrupt.
Note that the INTEG register can also be used to disable the external interrupt function.
Multi-function Interrupt
Within these devices there are four or six Multi-function interrupts. Unlike the other independent
interrupts, these interrupts have no independent source, but rather are formed from the Touch Key Module,
Timer Module, Low Voltage Detector, EEPROM, External Peripheral and Time Base interrupt sources.
A Multi-function interrupt request will take place when any of the Multi-function interrupt request
flags, MFnF are set. The Multi-function interrupt flags will be set when any of their included
functions generate an interrupt request flag. To allow the program to branch to its respective interrupt
vector address, when the Multi-function interrupt is enabled and the stack is not full, and either one
of the interrupts contained within each of Multi-function interrupt occurs, a subroutine call to one of
the Multi-function interrupt vectors will take place. When the interrupt is serviced, the related
Multi-Function request flag, will be automatically reset and the EMI bit will be automatically
cleared to disable other interrupts.
However, it must be noted that, although the Multi-function Interrupt flags will be automatically
reset when the interrupt is serviced, the request flags from the original source of the Multi-function
interrupts, namely the Touch Key module timer interrupts, will not be automatically reset and must
be manually reset by the application program.
Time Base Interrupts
The function of the Time Base Interrupts is to provide regular time signal in the form of an internal
interrupt. They are controlled by the overflow signals from their respective timer functions. When
these happens their respective interrupt request flags, TB0F or TB1F will be set. To allow the
program to branch to their respective interrupt vector addresses, the global interrupt enable bit, EMI
and Time Base enable bits, TB0E or TB1E, must first be set.
When the interrupt is enabled, the stack is not full and the Time Base overflows, a subroutine call
to their respective vector locations will take place. When the interrupt is serviced, the respective
interrupt request flag, TB0F or TB1F, will be automatically reset and the EMI bit will be cleared to
disable other interrupts.
Rev. 1.40
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BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
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.
Time Base Structure – BS85B12-3/BS85C20-3
T B 0 2 ~ T B 0 0
fS
Y S
fT
L X T
/4
M
B C
fT
U
B
X
T B C K B it
2
2
8
~ 2
1 5
T im e B a s e 0 In te r r u p t
1 2
~ 2
1 5
T im e B a s e 1 In te r r u p t
T B 1 1 ~ T B 1 0
Time Base Structure – BS85C20-5
TBC Register – BS85C12-3/BS85C20-3
Rev. 1.40
Bit
7
6
5
4
3
2
1
0
Name
TBON
TBCK
TB11
TB10
D3
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: TB0 and TB1 Control
0: disable
1: enable
Bit 6
TBCK: Select fTB Clock
0: fTBC
1: fSYS/4
Bit 5~4
TB11~TB10: Select Time Base 1 Time-out Period
0: 4096/fTB
1: 8192/fTB
2: 16384/fTB
3: 32768/fTB
Bit 3
Undefined bit
This bit can be read or written by user software program.
Bit 2~0
TB02~TB00: Select Time Base 0 Time-out Period
0: 256/fTB
1: 512/fTB
2: 1024/fTB
3: 2048/fTB
4: 4096/fTB
5: 8192/fTB
6: 16384/fTB
7: 32768/fTB
147
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Touch Key Flash MCU with LCD/LED Driver
TBC Register – BS85C20-5
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: TB0 and TB1 Control
0: disable
1: enable
Bit 6
TBCK: Select fTB Clock
0: fTBC
1: fSYS/4
Bit 5~4
TB11~TB10: Select Time Base 1 Time-out Period
0: 4096/fTB
1: 8192/fTB
2: 16384/fTB
3: 32768/fTB
Bit 3
LXTLP: LXT Low Power Control
0: disable
1: enable
Bit 2~0
TB02~TB00: Select Time Base 0 Time-out Period
0: 256/fTB
1: 512/fTB
2: 1024/fTB
3: 2048/fTB
4: 4096/fTB
5: 8192/fTB
6: 16384/fTB
7: 32768/fTB
External Peripheral Interrupt
The External Peripheral Interrupt operates in a similar way to the external interrupt and is contained
within the Multi-function Interrupt. A Peripheral Interrupt request will take place when the External
Peripheral Interrupt request flag, XPF, is set, which occurs when a negative edge transition appears
on the PINT pin. To allow the program to branch to its respective interrupt vector address, the
global interrupt enable bit, EMI, external peripheral interrupt enable bit, XPE, and associated
Multi-function interrupt enable bit, must first be set. When the interrupt is enabled, the stack is not
full and a negative transition appears on the External Peripheral Interrupt pin, a subroutine call to
the respective Multi-function Interrupt, will take place. When the External Peripheral 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 XPF flag will not be automatically cleared, it has to be cleared by the application program.
The external peripheral interrupt pin is pin-shared with several other pins with different functions. It
must therefore be properly configured to enable it to operate as an External Peripheral Interrupt pin.
Rev. 1.40
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Touch Key Flash MCU with LCD/LED Driver
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.
TM Interrupts
The Compact and Standard Type TMs have two interrupts each, while the Enhanced Type TM has
three interrupts. All of the TM interrupts are contained within the Multi-function Interrupts. For each
of the Compact and Standard Type TMs there are two interrupt request flags TnPF and TnAF and
two enable bits TnPE and TnAE. For the Enhanced Type TM there are three interrupt request flags
TnPF, TnAF and TnBF and three enable bits TnPE, TnAE and TnBE. A TM interrupt request will
take place when any of the TM request flags are set, a situation which occurs when a TM comparator
P, A or B match situation happens.
To allow the program to branch to its respective interrupt vector address, the global interrupt enable
bit, EMI, respective TM Interrupt enable bit, and relevant Multi-function Interrupt enable bit, MFnE,
must first be set. When the interrupt is enabled, the stack is not full and a TM comparator match
situation occurs, a subroutine call to the relevant Multi-function Interrupt vector locations, will take
place. When the TM interrupt is serviced, the EMI bit will be automatically cleared to disable other
interrupts, however only the related MFnF flag will be automatically cleared. As the TM interrupt
request flags will not be automatically cleared, they have to be cleared by the application program.
EEPROM Interrupt
The EEPROM Interrupt, is contained within the Multi-function Interrupt. An EEPROM Interrupt
request will take place when the EEPROM Interrupt request flag, DEF, is set, which occurs when
an EEPROM Write cycle ends. To allow the program to branch to its respective interrupt vector
address, the global interrupt enable bit, EMI, EEPROM 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 Interrupt is serviced, the EMI bit will be automatically
cleared to disable other interrupts, however only the Multi-function interrupt request flag will be
also automatically cleared. As the DEF flag will not be automatically cleared, it has to be cleared by
the application program.
Touch Key Interrupts
For a Touch Key interrupt to occur, the global interrupt enable bit, EMI, and the corresponding Touch
Key interrupt enable TKMnE must be first set. An actual Touch Key interrupt will take place when the
Touch Key request flag. TKMnF, is set, a situation that will occur when the 13-bit time slot counter in
the relevant Touch Key module overflows. When the interrupt is enabled, the stack is not full and the
Touch Key time slot counter overflow occurs, a subroutine call to the relevant Touch Key interrupt
vector, will take place. When the interrupt is serviced, the Touch Key interrupt request flag, TKMnF,
will be automatically reset and the EMI bit will be automatically cleared to disable other interrupts.
Rev. 1.40
149
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Touch Key Flash MCU with LCD/LED Driver
SIM Interrupt
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. 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 a byte of data has been transmitted or received by the SIM interface, a
subroutine call to the respective interrupt vector, will take place. When the Serial Interface Interrupt
is serviced, the SIM interrupt request flag, SIF, will be automatically cleared and the EMI bit will be
automatically cleared to disable other interrupts.
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.
As only the Program Counter is pushed onto the stack, then when the interrupt is serviced, if the
contents of the accumulator, status register or other registers are altered by the interrupt service program,
their contents should be saved to the memory at the beginning of the interrupt service routine.
To return from an interrupt subroutine, either a RET or RETI instruction may be executed. The RETI
instruction in addition to executing a return to the main program also automatically sets the EMI
bit high to allow further interrupts. The RET instruction however only executes a return to the main
program leaving the EMI bit in its present zero state and therefore disabling the execution of further
interrupts.
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Low Voltage Detector – LVD
Each device has a Low Voltage Detector function, also known as LVD. This enabled the device to
monitor the power supply voltage, VDD, and provide a warning signal should it fall below a certain
level. This function may be especially useful in battery applications where the supply voltage will
gradually reduce as the battery ages, as it allows an early warning battery low signal to be generated.
The Low Voltage Detector also has the capability of generating an interrupt signal.
LVD Register
The Low Voltage Detector function is controlled using a single register with the name LVDC. Three
bits in this register, VLVD2~VLVD0, are used to select one of eight fixed voltages below which a
low voltage condition will be detemined. A low voltage condition is indicated when the LVDO bit is
set. If the LVDO bit is low, this indicates that the VDD voltage is above the preset low voltage value.
The LVDEN bit is used to control the overall on/off function of the low voltage detector. Setting the
bit high will enable the low voltage detector. Clearing the bit to zero will switch off the internal low
voltage detector circuits. As the low voltage detector will consume a certain amount of power, it may
be desirable to switch off the circuit when not in use, an important consideration in power sensitive
battery powered applications.
LVDC Register
Rev. 1.40
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 Detect
1: Low Voltage Detect
Bit 4
LVDEN: Low Voltage Detector Control
0: Disable
1: Enable
Bit 3
unimplemented, read as "0"
Bit 2~0
VLVD2 ~ VLVD0: Select LVD Voltage
000: undefined
001: undefined
010: undefined
011: 2.7V
100: 3.0V
101: 3.3V
110: 3.6V
111: 4.2V
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LVD Operation
The Low Voltage Detector function operates by comparing the power supply voltage, VDD, with a
pre-specified voltage level stored in the LVDC register. This has a range of between 2.0V and 4.2V.
When the power supply voltage, VDD, falls below this pre-determined value, the LVDO bit will be
set high indicating a low power supply voltage condition. The Low Voltage Detector function is
supplied by a reference voltage which will be automatically enabled. When the device is powered
down the low voltage detector will remain active if the LVDEN bit is high. After enabling the Low
Voltage Detector, a time delay tLVDS should be allowed for the circuitry to stabilise before reading the
LVDO bit. Note also that as the VDD voltage may rise and fall rather slowly, at the voltage nears that
of VLVD, there may be multiple bit LVDO transitions.
LVD Operation
The Low Voltage Detector also has its own interrupt which is contained within one of the Multifunction interrupts, providing an alternative means of low voltage detection, in addition to polling
the LVDO bit. The interrupt will only be generated after a delay of tLVD after the LVDO bit has been
set high by a low voltage condition. When the device is powered down the Low Voltage Detector
will remain active if the LVDEN bit is high. In this case, the LVF interrupt request flag will be set,
causing an interrupt to be generated if VDD falls below the preset LVD voltage. This will cause the
device to wake-up from the SLEEP or IDLE Mode, however if the Low Voltage Detector wake up
function is not required then the LVF flag should be first set high before the device enters the SLEEP
or IDLE Mode.
LCD Driver – SCOM and SSEG Function
The devices can drive LCD panels by simulating LCD signals on their I/O pins using the application
program. Both Command and Segment signals can be emulated in this way.
LCD Operation
The LCD driving Common pins, SCOM0~SCOM3, and Segment pins, SSEG0~SSEGn, are pin
shared with other I/O pins. These LCD driving pins are configured using a series of LCD control
registers which in addition to controlling the overall on/off function also controls the bias voltage
setup function. This enables the LCD COM and SEG driver to generate the necessary VSS, (1/3)VDD,
(2/3)VDD voltage and VDD levels for full LCD 1/3 bias operation.
The SLCDEN bit in the LCD control register is the overall master control for the LCD driver, and
this bit is used in conjunction with the COMnEN and SEGnEN bits to select which I/O Port pins
are used for LCD driving. Note that the Port Control register does not need to first setup the pins as
outputs to enable the LCD driver operation.
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Touch Key Flash MCU with LCD/LED Driver
V
D D
V D D
V D D
S C O M 0
S C O M 1
(2 /3 )V D D
S C O M 2
S C O M 3
A n a lo g
S w itc h
L C D V o lta g e
S e le c t C ir c u it
(1 /3 )V D D
S S E G 0
S S E G 1
V S S
S S E G n
V S S
V S S
LCD Driver Structure
The accompanying waveform diagram shows a typical 1/3 Bias LCD waveform generated using the
application program. Note that the depiction of a "1" in the diagram illustrates an illuminated LCD
pixel. The COM signal polarity generated on pins SCOM0~SCOM3, whether 0 or 1, are generated
using the corresponding I/O data registers, which are bits PB0~PB3 in the PB register.
Note: The logical values shown in the diagram are the PB I/O register values, PB0~PB3.
1/3 Bias LCD Waveform
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A cyclic LCD waveform includes two frames, known as Frame 0 and Frame 1 for which the
following offers a functional explanation.
In Frame 0
To select Frame 0 clear the FRAME bit to 0.
In frame 0, the COM signal output can have a value of VDD, or have a Vbias value of 1/3VDD. The
SEG signal can have a value of VSS, or have a Vbias value of 2/3VDD.
In Frame 1
In frame 1, the COM signal output can have a value of VSS, have a Vbias value of 2/3VDD. The SEG
signal can have a value of VDD have a Vbias value of 1/3VDD.
The COM0~COMn waveform is controlled by the application program using the FRAME bit, and the
corresponding I/O data register for the respective COM pin to determine whether the COM0~COMn
output has a value of either VDD, VSS or Vbias. The SEG0~SEGm waveform is controlled in a similar
way using the FRAME bit and the corresponding I/O data register for the respective SEG pin to
determine whether the SEG0~SEGn output has a value of either VDD, VSS or Vbias.
LCD Bias Control
The LCD COM and SEG driver enable a range of selections to be provided to suit the requirement
of the LCD panel which are being used. The bias resistor choice is implemented using the ISEL1
and ISEL0 bits in the LCD control register.
LCD Driver Registers
SLCDC0 Register
Bit
7
6
5
Name
FRAME
ISEL1
ISEL0
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
Bit 6~5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Rev. 1.40
4
3
2
1
0
SLCDEN COM3EN COM2EN COM1EN COM0EN
FRAME: Present Frame output select – Frame 0 or Frame 1
0: Frame 0
1: Frame 1
ISEL1, ISEL0: SCOM and SSEG operating current selection – VDD=5V
0: 25µA
1: 50µA
2: 100µA
3: 200µA
SLCDEN: SCOM and SSEG module on/off control
0: disable
1: enable
The SCOMn and SSEGm lines can be enabled using COMnEN and SEGmEN if
SLCDEN=1. When SLCDEN=0, then the SCOMn and SSEGm outputs will be fixed
at a VDD level.
COM3EN: SCOM3 or other function selection
0: Other function
1: SCOM3
COM2EN: SCOM2 or other function selection
0: Other function
1: SCOM2
COM1EN: SCOM1 or other function selection
0: Other function
1: SCOM1
COM0EN: SCOM0 or other function selection
0: Other function
1: SCOM0
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SLCDC1 Register
Bit
Name
7
6
5
4
3
2
1
0
SEG7EN SEG6EN SEG5EN SEG4EN SEG3EN SEG2EN SEG1EN SEG0EN
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
SEG7EN~SEG0EN: SSEG7~SSEG0 or other function selection
0: Other function
1: SSEG7~SSEG0
Bit 7~0
SLCDC2 Register – BS85B12-3
Bit
7
6
5
4
3
2
1
0
Name
—
—
SEG13EN
SEG12EN
SEG11EN
SEG10EN
SEG9EN
SEG8EN
R/W
—
—
R/W
R/W
R/W
R/W
R/W
R/W
POR
—
—
0
0
0
0
0
0
Bit 7~6
unimplemented, read as "0"
Bit 5~0
SEG13EN~SEG8EN: SSEG13~SSEG8 or other function selection
0: Other function
1: SSEG13~SSEG8
SLCDC2 Register – BS85C20-3/BS85C20-5
Bit
Name
7
6
5
4
3
2
1
0
SEG15EN SEG14EN SEG13EN SEG12EN SEG11EN SEG10EN SEG9EN SEG8EN
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
1
0
Bit 7~6
unimplemented, read as "0"
Bit 5~0
SEG15EN~SEG8EN: SSEG15~SSEG8 or other function selection
0: Other function
1: SSEG15~SSEG8
SLCDC3 Register – BS85C20-3/BS85C20-5
Rev. 1.40
Bit
7
6
Name
TCK2PS
—
5
4
3
2
R/W
R/W
—
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
—
0
0
0
0
0
0
SEG21EN SEG20EN SEG19EN SEG18EN SEG17EN SEG16EN
Bit 7
TCK2PS: TCK2 Pin Remapping Control
Described elsewhere
Bit 6
unimplemented, read as "0"
Bit 5~0
SEG21EN~SEG16EN: SSEG21~SSEG16 or other function selection
0: Other function
1: SSEG21~SSEG16
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LED Driver
The devices contain an LED driver function offering high current output drive capability which can
be used to drive external LEDs.
LED Driver Operation
Depending upon which device is chosen various I/O pins have a capability of providing LED high
current drive outputs.
Device
LED Drive Pins
BS85B12-3
PA0~PA7 (high source current)
PB0~PB5 (high sink current)
BS85C20-3
/BS85C20-5
PA0~PA7 (high source current)
PB0~PB7 (high sink current)
PE0~PE5 (high source current)
Whether a normal current sink capability or high current sink capability is used, the selection is
made using the SLEDCn registers.
LED Driver Registers
SLEDC0 Register – BS85B12-3
Bit
7
6
5
4
3
2
1
0
Name
—
—
D5
D4
D3
D2
D1
D0
R/W
—
—
R/W
R/W
R/W
R/W
R/W
R/W
—
—
0
0
0
0
0
0
POR
Bit 7~6
Bit 5~0
unimplemented, read as "0"
D5~D0: PB5~PB0 I/O output sink current select
0: Normal output sink current
1: ×2 output sink current
SLEDC0 Register – BS85C20-3/BS85C20-5
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: PB7~PB0 I/O output sink current select
0: Normal output sink current
1: ×2 output sink current
SLEDC1 Register – All Devices
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: PA7~PA0 I/O output source current select
0: Normal output source current
1: ×2 output source current
SLEDC2 Register – BS85C20-3/BS85C20-5
Bit
7
6
5
4
3
2
1
0
Name
—
—
D5
D4
D3
D2
D1
D0
R/W
—
—
R/W
R/W
R/W
R/W
R/W
R/W
POR
—
—
0
0
0
0
0
0
Bit 7~6
Bit 5~0
Rev. 1.40
unimplemented, read as "0"
D5~D0: PE5~PE0 I/O output source current select
0: Normal output source current
1: ×2 output source current
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Application Circuits

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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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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Touch Key Flash MCU with LCD/LED Driver
Logical and Rotate Operation
The standard logical operations such as AND, OR, XOR and CPL all have their own instruction
within the Holtek microcontroller instruction set. As with the case of most instructions involving
data manipulation, data must pass through the Accumulator which may involve additional
programming steps. In all logical data operations, the zero flag may be set if the result of the
operation is zero. Another form of logical data manipulation comes from the rotate instructions such
as RR, RL, RRC and RLC which provide a simple means of rotating one bit right or left. Different
rotate instructions exist depending on program requirements. Rotate instructions are useful for serial
port programming applications where data can be rotated from an internal register into the Carry
bit from where it can be examined and the necessary serial bit set high or low. Another application
which rotate data operations are used is to implement multiplication and division calculations.
Branches and Control Transfer
Program branching takes the form of either jumps to specified locations using the JMP instruction
or to a subroutine using the CALL instruction. They differ in the sense that in the case of a
subroutine call, the program must return to the instruction immediately when the subroutine has
been carried out. This is done by placing a return instruction "RET" in the subroutine which will
cause the program to jump back to the address right after the CALL instruction. In the case of a JMP
instruction, the program simply jumps to the desired location. There is no requirement to jump back
to the original jumping off point as in the case of the CALL instruction. One special and extremely
useful set of branch instructions are the conditional branches. Here a decision is first made regarding
the condition of a certain data memory or individual bits. Depending upon the conditions, the
program will continue with the next instruction or skip over it and jump to the following instruction.
These instructions are the key to decision making and branching within the program perhaps
determined by the condition of certain input switches or by the condition of internal data bits.
Bit Operations
The ability to provide single bit operations on Data Memory is an extremely flexible feature of all
Holtek microcontrollers. This feature is especially useful for output port bit programming where
individual bits or port pins can be directly set high or low using either the "SET [m].i" or "CLR [m].
i" instructions respectively. The feature removes the need for programmers to first read the 8-bit
output port, manipulate the input data to ensure that other bits are not changed and then output the
port with the correct new data. This read-modify-write process is taken care of automatically when
these bit operation instructions are used.
Table Read Operations
Data storage is normally implemented by using registers. However, when working with large
amounts of fixed data, the volume involved often makes it inconvenient to store the fixed data in
the Data Memory. To overcome this problem, Holtek microcontrollers allow an area of Program
Memory to be setup as a table where data can be directly stored. A set of easy to use instructions
provides the means by which this fixed data can be referenced and retrieved from the Program
Memory.
Other Operations
In addition to the above functional instructions, a range of other instructions also exist such as
the "HALT" instruction for Power-down operations and instructions to control the operation of
the Watchdog Timer for reliable program operations under extreme electric or electromagnetic
environments. For their relevant operations, refer to the functional related sections.
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Touch Key Flash MCU with LCD/LED Driver
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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Touch Key Flash MCU with LCD/LED Driver
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 (last page) to TBLH and Data Memory
2Note
None
No operation
Clear Data Memory
Set Data Memory
Clear Watchdog Timer
Pre-clear Watchdog Timer
Pre-clear Watchdog Timer
Swap nibbles of Data Memory
Swap nibbles of Data Memory with result in ACC
Enter power down mode
1
1Note
1Note
1
1
1
1Note
1
1
None
None
None
TO, PDF
TO, PDF
TO, PDF
None
None
TO, PDF
Data Move
MOV A,[m]
MOV [m],A
MOV A,x
Bit Operation
CLR [m].i
SET [m].i
Branch
JMP addr
SZ [m]
SZA [m]
SZ [m].i
SNZ [m].i
SIZ [m]
SDZ [m]
SIZA [m]
SDZA [m]
CALL addr
RET
RET A,x
RETI
Table Read
TABRDL [m]
Miscellaneous
NOP
CLR [m]
SET [m]
CLR WDT
CLR WDT1
CLR WDT2
SWAP [m]
SWAPA [m]
HALT
Note: 1. For skip instructions, if the result of the comparison involves a skip then two cycles are required, if no
skip takes place only one cycle is required.
2. Any instruction which changes the contents of the PCL will also require 2 cycles for execution.
3. For the "CLR WDT1" and "CLR WDT2" instructions the TO and PDF flags may be affected by the
execution status. The TO and PDF flags are cleared after both "CLR WDT1" and "CLR WDT2"
instructions are consecutively executed. Otherwise the TO and PDF flags remain unchanged.
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Touch Key Flash MCU with LCD/LED Driver
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
Rev. 1.40
162
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
CALL addr
Description
Operation
Affected flag(s)
Subroutine call
Unconditionally calls a subroutine at the specified address. The Program Counter then
increments by 1 to obtain the address of the next instruction which is then pushed onto the
stack. The specified address is then loaded and the program continues execution from this
new address. As this instruction requires an additional operation, it is a two cycle instruction.
Stack ← Program Counter + 1
Program Counter ← addr
None
CLR [m]
Description
Operation
Affected flag(s)
Clear Data Memory
Each bit of the specified Data Memory is cleared to 0.
[m] ← 00H
None
CLR [m].i
Description
Operation
Affected flag(s)
Clear bit of Data Memory
Bit i of the specified Data Memory is cleared to 0.
[m].i ← 0
None
CLR WDT
Description
Operation
Affected flag(s)
Clear Watchdog Timer
The TO, PDF flags and the WDT are all cleared.
WDT cleared
TO ← 0
PDF ← 0
TO, PDF
CLR WDT1
Description
Operation
Affected flag(s)
Pre-clear Watchdog Timer
The TO, PDF flags and the WDT are all cleared. Note that this instruction works in
conjunction with CLR WDT2 and must be executed alternately with CLR WDT2 to have
effect. Repetitively executing this instruction without alternately executing CLR WDT2 will
have no effect.
WDT cleared
TO ← 0
PDF ← 0
TO, PDF
CLR WDT2
Description
Operation
Affected flag(s)
Pre-clear Watchdog Timer
The TO, PDF flags and the WDT are all cleared. Note that this instruction works in conjunction
with CLR WDT1 and must be executed alternately with CLR WDT1 to have effect.
Repetitively executing this instruction without alternately executing CLR WDT1 will have no
effect.
WDT cleared
TO ← 0
PDF ← 0
TO, PDF
CPL [m]
Description
Operation
Affected flag(s)
Complement Data Memory
Each bit of the specified Data Memory is logically complemented (1′s complement). Bits which
previously contained a 1 are changed to 0 and vice versa.
[m] ← [m]
Z
Rev. 1.40
163
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
CPLA [m]
Description
Operation
Affected flag(s)
Complement Data Memory with result in ACC
Each bit of the specified Data Memory is logically complemented (1′s complement). Bits which
previously contained a 1 are changed to 0 and vice versa. The complemented result is stored in
the Accumulator and the contents of the Data Memory remain unchanged.
ACC ← [m]
Z
DAA [m]
Description
Operation
Affected flag(s)
Decimal-Adjust ACC for addition with result in Data Memory
Convert the contents of the Accumulator value to a BCD (Binary Coded Decimal) value
resulting from the previous addition of two BCD variables. If the low nibble is greater than 9
or if AC flag is set, then a value of 6 will be added to the low nibble. Otherwise the low nibble
remains unchanged. If the high nibble is greater than 9 or if the C flag is set, then a value of 6
will be added to the high nibble. Essentially, the decimal conversion is performed by adding
00H, 06H, 60H or 66H depending on the Accumulator and flag conditions. Only the C flag
may be affected by this instruction which indicates that if the original BCD sum is greater than
100, it allows multiple precision decimal addition.
[m] ← ACC + 00H or
[m] ← ACC + 06H or [m] ← ACC + 60H or
[m] ← ACC + 66H
C
DEC [m]
Description
Operation
Affected flag(s)
Decrement Data Memory
Data in the specified Data Memory is decremented by 1.
[m] ← [m] − 1
Z
DECA [m]
Description
Operation
Affected flag(s)
Decrement Data Memory with result in ACC
Data in the specified Data Memory is decremented by 1. The result is stored in the
Accumulator. The contents of the Data Memory remain unchanged.
ACC ← [m] − 1
Z
HALT
Description
Operation
Affected flag(s)
Enter power down mode
This instruction stops the program execution and turns off the system clock. The contents of the Data Memory and registers are retained. The WDT and prescaler are cleared. The power
down flag PDF is set and the WDT time-out flag TO is cleared.
TO ← 0
PDF ← 1
TO, PDF
INC [m]
Description
Operation
Affected flag(s)
Increment Data Memory
Data in the specified Data Memory is incremented by 1.
[m] ← [m] + 1
Z
INCA [m]
Description
Operation
Affected flag(s)
Increment Data Memory with result in ACC
Data in the specified Data Memory is incremented by 1. The result is stored in the Accumulator.
The contents of the Data Memory remain unchanged.
ACC ← [m] + 1
Z
Rev. 1.40
164
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
JMP addr
Description
Operation
Affected flag(s)
Jump unconditionally
The contents of the Program Counter are replaced with the specified address. Program
execution then continues from this new address. As this requires the insertion of a dummy
instruction while the new address is loaded, it is a two cycle instruction.
Program Counter ← addr
None
MOV A,[m]
Description
Operation
Affected flag(s)
Move Data Memory to ACC
The contents of the specified Data Memory are copied to the Accumulator.
ACC ← [m]
None
MOV A,x
Description
Operation
Affected flag(s)
Move immediate data to ACC
The immediate data specified is loaded into the Accumulator.
ACC ← x
None
MOV [m],A
Description
Operation
Affected flag(s)
Move ACC to Data Memory
The contents of the Accumulator are copied to the specified Data Memory.
[m] ← ACC
None
NOP
Description
Operation
Affected flag(s)
No operation
No operation is performed. Execution continues with the next instruction.
No operation
None
OR A,[m]
Description
Operation
Affected flag(s)
Logical OR Data Memory to ACC
Data in the Accumulator and the specified Data Memory perform a bitwise
logical OR operation. The result is stored in the Accumulator.
ACC ← ACC ″OR″ [m]
Z
OR A,x
Description
Operation
Affected flag(s)
Logical OR immediate data to ACC
Data in the Accumulator and the specified immediate data perform a bitwise logical OR operation. The result is stored in the Accumulator.
ACC ← ACC ″OR″ x
Z
ORM A,[m]
Description
Operation
Affected flag(s)
Logical OR ACC to Data Memory
Data in the specified Data Memory and the Accumulator perform a bitwise logical OR operation. The result is stored in the Data Memory.
[m] ← ACC ″OR″ [m]
Z
RET
Description
Operation
Affected flag(s)
Return from subroutine
The Program Counter is restored from the stack. Program execution continues at the restored
address.
Program Counter ← Stack
None
Rev. 1.40
165
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
RET A,x
Description
Operation
Affected flag(s)
Return from subroutine and load immediate data to ACC
The Program Counter is restored from the stack and the Accumulator loaded with the specified immediate data. Program execution continues at the restored address.
Program Counter ← Stack
ACC ← x
None
RETI
Description
Operation
Affected flag(s)
Return from interrupt
The Program Counter is restored from the stack and the interrupts are re-enabled by setting the
EMI bit. EMI is the master interrupt global enable bit. If an interrupt was pending when the RETI instruction is executed, the pending Interrupt routine will be processed before returning to the main program.
Program Counter ← Stack
EMI ← 1
None
RL [m]
Description
Operation
Affected flag(s)
Rotate Data Memory left
The contents of the specified Data Memory are rotated left by 1 bit with bit 7 rotated into bit 0.
[m].(i+1) ← [m].i; (i=0~6)
[m].0 ← [m].7
None
RLA [m]
Description
Operation
Affected flag(s)
Rotate Data Memory left with result in ACC
The contents of the specified Data Memory are rotated left by 1 bit with bit 7 rotated into bit 0.
The rotated result is stored in the Accumulator and the contents of the Data Memory remain
unchanged.
ACC.(i+1) ← [m].i; (i=0~6)
ACC.0 ← [m].7
None
RLC [m]
Description
Operation
Affected flag(s)
Rotate Data Memory left through Carry
The contents of the specified Data Memory and the carry flag are rotated left by 1 bit. Bit 7
replaces the Carry bit and the original carry flag is rotated into bit 0.
[m].(i+1) ← [m].i; (i=0~6)
[m].0 ← C
C ← [m].7
C
RLCA [m]
Description
Operation
Affected flag(s)
Rotate Data Memory left through Carry with result in ACC
Data in the specified Data Memory and the carry flag are rotated left by 1 bit. Bit 7 replaces the
Carry bit and the original carry flag is rotated into the bit 0. The rotated result is stored in the
Accumulator and the contents of the Data Memory remain unchanged.
ACC.(i+1) ← [m].i; (i=0~6)
ACC.0 ← C
C ← [m].7
C
RR [m]
Description
Operation
Affected flag(s)
Rotate Data Memory right
The contents of the specified Data Memory are rotated right by 1 bit with bit 0 rotated into bit 7.
[m].i ← [m].(i+1); (i=0~6)
[m].7 ← [m].0
None
Rev. 1.40
166
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
RRA [m]
Description
Operation
Affected flag(s)
Rotate Data Memory right with result in ACC
Data in the specified Data Memory and the carry flag are rotated right by 1 bit with bit 0
rotated into bit 7. The rotated result is stored in the Accumulator and the contents of the
Data Memory remain unchanged.
ACC.i ← [m].(i+1); (i=0~6)
ACC.7 ← [m].0
None
RRC [m]
Description
Operation
Affected flag(s)
Rotate Data Memory right through Carry
The contents of the specified Data Memory and the carry flag are rotated right by 1 bit. Bit 0
replaces the Carry bit and the original carry flag is rotated into bit 7.
[m].i ← [m].(i+1); (i=0~6)
[m].7 ← C
C ← [m].0
C
RRCA [m]
Description
Operation
Affected flag(s)
Rotate Data Memory right through Carry with result in ACC
Data in the specified Data Memory and the carry flag are rotated right by 1 bit. Bit 0 replaces the Carry bit and the original carry flag is rotated into bit 7. The rotated result is stored in the Accumulator and the contents of the Data Memory remain unchanged.
ACC.i ← [m].(i+1); (i=0~6)
ACC.7 ← C
C ← [m].0
C
SBC A,[m]
Description
Operation
Affected flag(s)
Subtract Data Memory from ACC with Carry
The contents of the specified Data Memory and the complement of the carry flag are
subtracted from the Accumulator. The result is stored in the Accumulator. Note that if the result of subtraction is negative, the C flag will be cleared to 0, otherwise if the result is
positive or zero, the C flag will be set to 1.
ACC ← ACC − [m] − C
OV, Z, AC, C
SBCM A,[m]
Description
Operation
Affected flag(s)
Subtract Data Memory from ACC with Carry and result in Data Memory
The contents of the specified Data Memory and the complement of the carry flag are subtracted from the Accumulator. The result is stored in the Data Memory. Note that if the result of subtraction is negative, the C flag will be cleared to 0, otherwise if the result is positive or zero, the C flag will be set to 1.
[m] ← ACC − [m] − C
OV, Z, AC, C
SDZ [m]
Description
Operation
Affected flag(s)
Skip if decrement Data Memory is 0
The contents of the specified Data Memory are first decremented by 1. If the result is 0 the following instruction is skipped. As this requires the insertion of a dummy instruction while the next instruction is fetched, it is a two cycle instruction. If the result is not 0 the program proceeds with the following instruction.
[m] ← [m] − 1
Skip if [m]=0
None
Rev. 1.40
167
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
SDZA [m]
Description
Operation
Affected flag(s)
Skip if decrement Data Memory is zero with result in ACC
The contents of the specified Data Memory are first decremented by 1. If the result is 0, the following instruction is skipped. The result is stored in the Accumulator but the specified Data Memory contents remain unchanged. As this requires the insertion of a dummy
instruction while the next instruction is fetched, it is a two cycle instruction. If the result is not 0,
the program proceeds with the following instruction.
ACC ← [m] − 1
Skip if ACC=0
None
SET [m]
Description
Operation
Affected flag(s)
Set Data Memory
Each bit of the specified Data Memory is set to 1.
[m] ← FFH
None
SET [m].i
Description
Operation
Affected flag(s)
Set bit of Data Memory
Bit i of the specified Data Memory is set to 1.
[m].i ← 1
None
SIZ [m]
Description
Operation
Affected flag(s)
Skip if increment Data Memory is 0
The contents of the specified Data Memory are first incremented by 1. If the result is 0, the
following instruction is skipped. As this requires the insertion of a dummy instruction while the next instruction is fetched, it is a two cycle instruction. If the result is not 0 the program
proceeds with the following instruction.
[m] ← [m] + 1
Skip if [m]=0
None
SIZA [m]
Description
Operation
Affected flag(s)
Skip if increment Data Memory is zero with result in ACC
The contents of the specified Data Memory are first incremented by 1. If the result is 0, the following instruction is skipped. The result is stored in the Accumulator but the specified
Data Memory contents remain unchanged. As this requires the insertion of a dummy
instruction while the next instruction is fetched, it is a two cycle instruction. If the result is not
0 the program proceeds with the following instruction.
ACC ← [m] + 1
Skip if ACC=0
None
SNZ [m].i
Description
Operation
Affected flag(s)
Skip if bit i of Data Memory is not 0
If bit i of the specified Data Memory is not 0, the following instruction is skipped. As this
requires the insertion of a dummy instruction while the next instruction is fetched, it is a two cycle instruction. If the result is 0 the program proceeds with the following instruction.
Skip if [m].i ≠ 0
None
SUB A,[m]
Description
Operation
Affected flag(s)
Subtract Data Memory from ACC
The specified Data Memory is subtracted from the contents of the Accumulator. The result is stored in the Accumulator. Note that if the result of subtraction is negative, the C flag will be cleared to 0, otherwise if the result is positive or zero, the C flag will be set to 1.
ACC ← ACC − [m]
OV, Z, AC, C
Rev. 1.40
168
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
SUBM A,[m]
Description
Operation
Affected flag(s)
Subtract Data Memory from ACC with result in Data Memory
The specified Data Memory is subtracted from the contents of the Accumulator. The result is stored in the Data Memory. Note that if the result of subtraction is negative, the C flag will be cleared to 0, otherwise if the result is positive or zero, the C flag will be set to 1.
[m] ← ACC − [m]
OV, Z, AC, C
SUB A,x
Description
Operation
Affected flag(s)
Subtract immediate data from ACC
The immediate data specified by the code is subtracted from the contents of the Accumulator. The result is stored in the Accumulator. Note that if the result of subtraction is negative, the C flag will be cleared to 0, otherwise if the result is positive or zero, the C flag will be set to 1.
ACC ← ACC − x
OV, Z, AC, C
SWAP [m]
Description
Operation
Affected flag(s)
Swap nibbles of Data Memory
The low-order and high-order nibbles of the specified Data Memory are interchanged.
[m].3~[m].0 ↔ [m].7~[m].4
None
SWAPA [m]
Description
Operation
Affected flag(s)
Swap nibbles of Data Memory with result in ACC
The low-order and high-order nibbles of the specified Data Memory are interchanged. The result is stored in the Accumulator. The contents of the Data Memory remain unchanged.
ACC.3~ACC.0 ← [m].7~[m].4
ACC.7~ACC.4 ← [m].3~[m].0
None
SZ [m]
Description
Operation
Affected flag(s)
Skip if Data Memory is 0
If the contents of the specified Data Memory is 0, the following instruction is skipped. As this requires the insertion of a dummy instruction while the next instruction is fetched, it is a two cycle instruction. If the result is not 0 the program proceeds with the following instruction.
Skip if [m]=0
None
SZA [m]
Description
Operation
Affected flag(s)
Skip if Data Memory is 0 with data movement to ACC
The contents of the specified Data Memory are copied to the Accumulator. If the value is zero, the following instruction is skipped. As this requires the insertion of a dummy instruction while the next instruction is fetched, it is a two cycle instruction. If the result is not 0 the program proceeds with the following instruction.
ACC ← [m]
Skip if [m]=0
None
SZ [m].i
Description
Operation
Affected flag(s)
Skip if bit i of Data Memory is 0
If bit i of the specified Data Memory is 0, the following instruction is skipped. As this requires
the insertion of a dummy instruction while the next instruction is fetched, it is a two cycle
instruction. If the result is not 0, the program proceeds with the following instruction.
Skip if [m].i=0
None
Rev. 1.40
169
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
TABRDL [m]
Description
Operation
Affected flag(s)
Read table (last page) to TBLH and Data Memory
The low byte of the program code (last page) addressed by the table pointer (TBLP) is moved to the specified Data Memory and the high byte moved to TBLH.
[m] ← program code (low byte)
TBLH ← program code (high byte)
None
XOR A,[m]
Description
Operation
Affected flag(s)
Logical XOR Data Memory to ACC
Data in the Accumulator and the specified Data Memory perform a bitwise logical XOR operation. The result is stored in the Accumulator.
ACC ← ACC ″XOR″ [m]
Z
XORM A,[m]
Description
Operation
Affected flag(s)
Logical XOR ACC to Data Memory
Data in the specified Data Memory and the Accumulator perform a bitwise logical XOR operation. The result is stored in the Data Memory.
[m] ← ACC ″XOR″ [m]
Z
XOR A,x
Description
Operation
Affected flag(s)
Logical XOR immediate data to ACC
Data in the Accumulator and the specified immediate data perform a bitwise logical XOR operation. The result is stored in the Accumulator.
ACC ← ACC ″XOR″ x
Z
Rev. 1.40
170
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Package Information
Note that the package information provided here is for consultation purposes only. As this
information may be updated at regular intervals users are reminded to consult the Holtek website for
the latest version of the package information.
Additional supplementary information with regard to packaging is listed below. Click on the relevant
section to be transferred to the relevant website page.
• Further Package Information (include Outline Dimensions, Product Tape and Reel Specifications)
• Packing Meterials Information
• Carton information
Rev. 1.40
171
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
24-pin SKDIP (300mil) Outline Dimensions
Fig1. Full Lead Packages
Fig2. 1/2 Lead Packages
See Fig1
A
Min.
1.230
Dimensions in inch
Nom.
1.250
Max.
1.280
B
0.240
0.250
0.280
C
0.115
0.130
0.195
D
0.115
0.130
0.150
E
0.014
0.018
0.022
F
0.045
0.060
0.070
G
—
0.1 BSC
—
H
0.300
0.310
0.325
I
—
—
0.430
A
Min.
31.24
Dimensions in mm
Nom.
31.75
Max.
32.51
B
6.10
6.35
7.11
C
2.92
3.30
4.95
D
2.92
3.30
3.81
E
0.36
0.46
0.56
1.78
Symbol
Symbol
Rev. 1.40
F
1.14
1.52
G
—
2.54 BSC
—
H
7.62
7.87
8.26
I
—
—
10.92
172
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
See Fig2 − Type 1
A
Min.
1.160
Dimensions in inch
Nom.
1.185
Max.
1.195
Symbol
B
0.240
0.250
0.280
C
0.115
0.130
0.195
D
0.115
0.130
0.150
E
0.014
0.018
0.022
F
0.045
0.060
0.070
G
—
0.1 BSC
—
H
0.300
0.310
0.325
I
—
—
0.430
Symbol
Dimensions in mm
Min.
Nom.
Max.
30.35
A
29.46
30.10
B
6.10
6.35
7.11
C
2.92
3.30
4.95
D
2.92
3.30
3.81
E
0.36
0.46
0.56
F
1.14
1.52
1.78
G
—
2.54 BSC
—
H
7.62
7.87
8.26
I
—
—
10.92
A
Min.
1.145
Dimensions in inch
Nom.
1.165
Max.
1.185
See Fig2 − Type 2
Symbol
B
0.275
0.285
0.295
C
0.120
0.135
0.150
D
0.110
0.130
0.150
E
0.014
0.018
0.022
0.060
F
0.045
0.050
G
—
0.1 BSC
—
H
0.300
0.310
0.325
I
—
—
0.430
A
Min.
29.08
Dimensions in mm
Nom.
29.59
Max.
30.10
Symbol
Rev. 1.40
B
6.99
7.24
7.49
C
3.05
3.43
3.81
D
2.79
3.30
3.81
E
0.36
0.46
0.56
1.52
F
1.14
1.27
G
—
2.54 BSC
—
H
7.62
7.87
8.26
I
—
—
10.92
173
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
24-pin SOP (300mil) Outline Dimensions
Symbol
A
Dimensions in inch
Min.
Nom.
Max.
—
0.406 BSC
—
B
—
0.295 BSC
—
C
0.012
—
0.020
C’
—
0.606 BSC
—
D
—
—
0.104
E
—
0.050 BSC
—
F
0.004
—
0.012
G
0.016
—
0.050
H
0.008
—
0.013
α
0°
—
8°
Symbol
Rev. 1.40
Dimensions in mm
Min.
Nom.
A
—
10.30 BSC
Max.
—
B
—
7.5 BSC
—
C
0.31
—
0.51
C’
—
15.4 BSC
—
D
—
—
2.65
E
—
1.27 BSC
—
F
0.10
—
0.30
G
0.40
—
1.27
H
0.20
—
0.33
α
0°
―
8°
174
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
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. 1.40
Dimensions in mm
Min.
Nom.
Max.
—
A
—
6.0 BSC
B
—
3.9 BSC
—
C
0.20
—
0.30
C’
—
8.66 BSC
—
D
—
—
1.75
E
—
0.635 BSC
—
F
0.10
—
0.25
G
0.41
—
1.27
H
0.10
—
0.25
α
0°
—
8°
175
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
28-pin SKDIP (300mil) Outline Dimensions
Symbol
Dimensions in inch
Min.
Nom.
Max.
1.420
A
1.380
—
B
0.280
—
0.310
C
0.060
—
0.130
D
0.125
—
0.200
E
0.015
—
0.022
F
0.045
—
0.065
G
—
0.1 BSC
—
H
0.300
—
0.325
I
—
—
0.400
Symbol
Rev. 1.40
Dimensions in mm
Min.
Nom.
Max.
A
35.05
—
36.07
B
7.11
—
7.87
C
1.52
—
3.30
D
3.18
—
5.08
E
0.38
—
0.56
F
1.14
—
1.65
G
—
2.54 BSC
—
H
7.62
—
8.26
I
—
—
10.16
176
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
28-pin SOP (300mil) Outline Dimensions
Symbol
Dimensions in inch
Min.
Nom.
A
—
0.406 BSC
—
B
—
0.295 BSC
—
Max.
0.020
C
0.012
—
C’
—
0.705 BSC
—
D
—
—
0.104
E
—
0.050 BSC
—
F
0.004
—
0.012
G
0.016
—
0.050
H
0.008
—
0.013
α
0°
―
8°
Symbol
Rev. 1.40
Dimensions in mm
Min.
Nom.
Max.
A
—
10.30 BSC
—
B
—
7.5 BSC
—
C
0.31
—
0.51
C’
—
17.9 BSC
—
2.65
D
—
—
E
—
1.27 BSC
—
F
0.10
—
0.30
G
0.40
—
1.27
H
0.20
—
0.33
α
0°
―
8°
177
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
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. 1.40
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°
178
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
44-pin LQFP (10mm×10mm) (FP2.0mm) Outline Dimensions
Symbol
Dimensions in inch
Min.
Nom.
Max.
A
—
0.472 BSC
—
B
—
0.394 BSC
—
C
—
0.472 BSC
—
D
—
0.394 BSC
—
E
—
0.032 BSC
—
F
0.012
0.015
0.018
G
0.053
0.055
0.057
H
—
—
0.063
I
0.002
—
0.006
J
0.018
0.024
0.030
K
0.004
—
0.008
α
0°
—
7°
Symbol
Rev. 1.40
Dimensions in mm
Min.
Nom.
Max.
A
—
12.00 BSC
—
B
—
10.00 BSC
—
C
—
12.00 BSC
—
D
—
10.00 BSC
—
E
—
0.80 BSC
—
F
0.30
0.37
0.45
G
1.35
1.40
1.45
H
—
—
1.60
I
0.05
—
0.15
J
0.45
0.60
0.75
K
0.09
—
0.20
α
0°
—
7°
179
March 12, 2015
BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Copyright© 2015 by HOLTEK SEMICONDUCTOR INC.
The information appearing in this Data Sheet is believed to be accurate at the time
of publication. However, Holtek assumes no responsibility arising from the use of
the specifications described. The applications mentioned herein are used solely
for the purpose of illustration and Holtek makes no warranty or representation that
such applications will be suitable without further modification, nor recommends
the use of its products for application that may present a risk to human life due to
malfunction or otherwise. Holtek's products are not authorized for use as critical
components in life support devices or systems. Holtek reserves the right to alter
its products without prior notification. For the most up-to-date information, please
visit our web site at http://www.holtek.com.tw.
Rev. 1.40
180
March 12, 2015

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