Compact Type Tm - Ctm; Compact Tm Operation; Compact Type Tm Register Description - Holtek BS83A04C Manual

• Reading Data from the Counter Registers and CCRA
Step 1. Read data from the High Byte CTMDH, CTMAH
♦
– 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 CTMDL, CTMAL
♦
– This step reads data from the 8-bit buffer.
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 two external output
pins.
f /4 000
SYS
f 001
SYS
f /16 010
H
f /64 011
H
10-bit Count-up Counter
f 100
SUB
f 101
SUB
CTON
110
CTPAU
CTCK 111
CTCK2~CTCK0
Note: CTPB is the inverted output of CTP.

Compact TM Operation

At its core is a 10-bit count-up counter which is driven by a user selectable internal or external clock
source. There are also two internal comparators with the names, Comparator A and Comparator
P. These comparators will compare the value in the counter with CCRP and CCRA registers. The
CCRP is three bits wide whose value is compared with the highest three bits in the counter while the
CCRA is the ten bits and therefore compares with all counter bits.
The only way of changing the value of the 10-bit counter using the application program, is to
clear the counter by changing the CTON bit from low to high. The counter will also be cleared
automatically by a counter overflow or a compare match with one of its associated comparators.
When these conditions occur, a CTM interrupt signal will also usually be generated. The Compact
Type TM can operate in a number of different operational modes, can be driven by different clock
sources including an input pin and can also control two output pins. All operating setup conditions
are selected using relevant internal registers.

Compact Type TM Register Description

Overall operation of each Compact TM is controlled using several 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.
Rev. 1.00
4-Key Enhanced Touch I/O Flash MCU
CCRP
Comparator P Match
3-bit Comparator P
b7~b9
Counter Clear
b0~b9
Comparator A Match
10-bit Comparator A
CCRA
Compact Type TM Block Diagram
54
CTMPF Interrupt
CTOC
Output Polarity
0
1
Control Control
CTCCLR
CTM1, CTM0 CTPOL
CTIO1, CTIO0
CTMAF Interrupt
BS83A04C
CTP
Pin
Control
CTPB
PASn
March 24, 2020