EM73880 datasheet(17/40 Pages) EMC

17 / 40 page

* This specification are subject to be changed without notice.

EM73880

4-BIT MICRO-CONTROLLER FOR LCD PRODUCT

11.30.2001

Preliminary

Internal pulse

TimerB (TimerA )value

n+1

n+2

n+3

n+4

n+5

n+6

n+7

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

TimerB (TimerA) value n

n+1

n+2

n+3

n+4

n+5

n+6

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).

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.

PROGRAM EXAMPLE: To generate TRGA interrupt request after 60 ms with system clock LXlN=32KHz

LDIA #0100B;

EXAE;

enable mask 2

EICIL 110111B; interrupt latch

←0, enable EI

LDIA #0AH;

STATAL;

LDIA #00H;

STATAM;

LDIA #0FH;

STATAH;

LDIA #1000B;

OUTA P28; enable timerA with internal pulse rate: LXIN/23 Hz

NOTE:

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

Internal pulse rate: LXIN/23 ; LXIN = 32KHz

The time of timer counter count one = 23 /LXIN = 8/32768=0.244ms

The number of internal pulse to get timer overflow = 60 ms/ 0.244ms = 245.901= 0F6H

The preset value of timer/counter register = 1000H - 0F6H = 0F0AH

PULSE WIDTH MEASUREMENT MODE

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