W921E400A Datasheet, PDF (28/53 Pages) Winbond – 4-BIT MICROCONTROLLER

W921E400A/W921C400
In the pulse/period width measurement mode the measuring-data is the 1'S complement of the exact
data and the TM2 interrupt flag is set every 255 timer clock past or the 2nd trigger condition occurs.
So the measuerd pulse/peirod width is (255( N − 1) + TM 2) *T , N is the number of interrupt flag occurs,
TM2 is the 1'S complement of timer2 register, T is the period of timer 2 clock. The special function
input or output is from or to P5.1.
6.10.3 TM3
TM3 can perform the following functions:
1. 2 to19 order divider
2. Auto-reload timer
System
Clock
f SYS
1/4
f TM3
11-bit Prescaler
8 Order Divider
Interrupt Control
Register
TM3 Interrupt
Logic
High Speed
Clock
TM3 Control
Register
TM3 Set Register
(8 bits)
TM3 Control
Logic
TM3CR register: (address = 02FH, default data = 0H)
b3
b2
b1
b0
b3 b2 b1 b0 Input frequency (f_TM3 )
0000
fsys/2 Hz
0001
fsys/4 Hz
0010
fsys/8 Hz
0011
fsys/16 Hz
0100
fsys/32 Hz
0101
fsys/64 Hz
0110
fsys/128 Hz
0111
fsys/256 Hz
1000
fsys/512 Hz
1 0 0 1 fsys/1024 Hz
1 0 1 0 fsys/2048 Hz
The TM3 set register is divided into TM3 MSB data register (TM3MSB register, address = 030H,
default = 0FH) and TM3 LSB data register (TM3LSB register, address = 031H, default = 0FH).
- 28 -