EM73982 查看數據表（PDF） - ELAN Microelectronics

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EM73982

4-BIT MICROCONTROLLER

ELAN Microelectronics 

EM73982

4-BIT MICROCONTROLLER

TIMER/COUNTER FUNCTION

Timer/counterA can be programmable for timer, event counter and pulse width measurement. Each timer/

counter can execute any one of these functions independly.

EVENT COUNTER MODE

For event counter mode, timer/counter increases one at any rising edge of P8.1/TRGB for timerB (P8.3/

TRGA for timer A). When timerB (timerA) counts overflow, it will give interrupt control an interrupt request

TRGB (TRGA).

P8.1/TRGB (P8.3/TRGA)

TimerB (TimerA) value n n+1

n+2

n+3 n+4 n+5 n+6

PROGRAM EXAMPLE: Enable timerA with P28

LDIA #0100B;

OUTA P28; Enable timerA with event counter mode

TIMER MODE

For timer mode, timer/counter increase one at any rising edge of internal pulse. User can choose 4 kinds

of internal pulse rate by setting IPSB for timerB (IPSA for timerA).

When timer/counter counts overflow, TRGB (TRGA) will be generated to interrupt control unit.

Internal pulse

TimerB (TimerA )value n n+1 n+2 n+3 n+4 n+5 n+6 n+7

PROGRAM EXAMPLE: To generate TRGA interrupt request after 60 ms with system clock XlN=4MHz

LDIA #0100B;

EXAE; enable mask 2

EICIL 110111B; interrupt latch ←0, enable EI

LDIA #06H;

STATAL;

LDIA #01H;

STATAM;

LDIA #0FH;

STATAH;

LDIA #1000B;

OUTA P28; enable timerA with internal pulse rate: XIN/210 Hz

NOTE:

The preset value of timer/counter register is calculated as following procedure.

Internal pulse rate: XIN/210 ; XIN = 4MHz

The time of timer counter count one = 210 /XIN = 1024/4000=0.256ms

The number of internal pulse to get timer overflow = 60 ms/ 0.256ms = 234.375 = 0EAH

The preset value of timer/counter register = 1000H - 0EAH = 0F16H

PULSE WIDTH MEASUREMENT MODE

* This specification are subject to be changed without notice.

11.30.2001 18

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