Filter
Top Products
S3C8245/P8245/C8249/P8249 8-BIT TIMER A/B
11-9
F PROGRAMMING TIP — To generate 38 kHz, 1/3duty signal through P3.0
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 4 MHz (0.25 µs)
— TBDATAH = 8.795 µs/0.25 µs = 35.18, TBDATAL = 17.59 µs/0.25 µs = 70.36
— Set P3.0 to TBPWM mode.
ORG 0100H ; Reset address
START DI
•
•
•
LD TBDATAL,#(70-2) ; Set 17.5 µs
LD TBDATAH,#(35-2) ; Set 8.75 µs
LD TBCON,#00000110B ; Clock Source ← fxx
; Disable Timer B interrupt.
; Select repeat mode for Timer B.
; Start Timer B operation.
; Set Timer B Output flip-flop (TBOF) high.
;
LD P3CONL,#02H ; Set P3.0 to TBPWM mode.
; This command generates 38 kHz, 1/3 duty pulse signal
through P3.0.
•
•
•