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S3C84E5/C84E9/P84E9 8-BIT TIMER A/B
11-9
F PROGRAMMING TIP — To Generate 38 kHz, 1/3duty signal through P4.3
This example sets Timer B to the repeat mode, sets the oscillation frequency as the Timer B clock source, and
TBDATAH and TBDATAL to make a 38 kHz, 1/3 Duty carrier frequency. The program parameters are:
17.59
µ
s
37.9 kHz 1/3 Duty
8.795
µ
s
— Timer B is used in repeat mode
— Oscillation frequency is 16 MHz (0.0625 µs), fx=fxx/4=4MHz (0.25 µs)
— TBDATAH = 8.795 µs/0.25 µs = 35.18, TBDATAL = 17.59 µs/0.25 µs = 70.36
— Set P4.3 to TBPWM mode.
ORG 0100H ; Reset address
START DI
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LD TBDATAL,#(35-1) ; Set 17.5 µs
LD TBDATAH,#(70-1) ; Set 8.75 µs
LD TBCON,#00100111B ; Clock Source ← fxx/4
; Disable Timer B interrupt.
; Select repeat mode for Timer B.
; Start Timer B operation.
; Set Timer B Output flip-flop (T-FF) high.
;
LD P4CONLH,#03H ; Set P4.3 to TBPWM mode.
; This command generates 38 kHz, 1/3 duty pulse signal
through P4.3.
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