EM73201
4-BIT MICRO-CONTROLLER FOR GENERAL PURPOSE PRODUCT
TIMER / COUNTER ( TIMERA)
Timer/counters can support user three special functions:
1. Even counter
2. Timer.
3. Pulse-width measurement.
These three functions can be executed by timer/counter.
For timerA, the counter data is saved in timer register TAH, TAM, TAL, which user can set counter
initial value and read the counter value by W/B instruction "LDATAH (B,L), STATAH (B,L)".
The counter can be set initial value and send counter value to timer register. P28 is the command port
for timerA , user can choose different operation mode and different internal clock rate by setting the
port. When timer/counter overflow, it will generate a TRGA interrupt request to interrupt control unit.
INTERRUPT CONTROL
TRGA request
DATA BUS
12 BIT COUNTER
EVENT COUNTER CONTROL
P8.3/
TRGA
TIMER CONTROL
PULSE-WIDTH MEASUREMENT
internal clock
CONTROL
TMSA
IPSA
P28
TIMER/COUNTER CONTROL
P8.3/TRGA is the external timer inputs for timerA, it used in event counter and pulse-width
measurement mode.
Timer/counter command port: P28 is the command port for timer/counterA.
TIMER/COUNTER MODE SELECTION
Port 28
3
2
1
0
TMSA IPSA
TMSA
0 0
Function description
Stop
Initial state: 0000
0 1 Event counter mode
1 0
1 1
Timer mode
Pulse width measurement mode
* This specification are subject to be changed without notice.
13
7.20.1999
ELAN [ ELAN MICROELECTRONICS CORP ]
