need code which generate ir 38khz pwm using pic 12f675

[HARIS RASHID]

hi
i need code which generate ir 38 khz pwm using pic12f675

 

[hexreader]

hi
i need code which generate ir 38 khz pwm using pic12f675

You do not normally need PWM for 38KHz IR, just square waves.

This should do it:

;IRTX - use MPASM in relocatable mode

#include	p12f675.inc		;with analogue

	__CONFIG	0x0184
	errorlevel	-302		;prevent bank select warnings

#define	irout		GPIO,4	;pic pin 3 infra red output

;12f675 ram 20 to 5f hex
	udata_shr
timer1	res 1   	;shared by delay routines
timer2	res 1   	;shared by delay routines
timer3  res 1		;shared by delay routines
	
    code 	0		;reset vector

;initilisation starts here
start
	bcf		STATUS,RP0		;bank 0
	clrf	GPIO			;init GPIO
	movlw	0x0f			;set I/O bits
	movwf	CMCON			;digital I/O
	bsf		STATUS,RP0		;bank1
	clrf	ANSEL			;digital I/O (pic12f675 only)
	movlw	0x2a			;set I/O bits, 1=input
	movwf	TRISIO			;note GP3 pin4 can only be input
	movlw	0x28			;set weak pullup bits
	movwf	WPU
	bsf		OPTION_REG,7	;allow weak pullups

	bcf		STATUS,RP0		;bank 0
	bcf		irout			;be sure to turn off IR to prevent burnout

;tx test loop
tloop
	movlw	d'175'	;4.5ms mark
	call	pulse_ir_w
	movlw	d'163'	;4.5ms space
	call	wait_ir_w
    goto    tloop

; send w pulses of 38 Khz to IR LED
pulse_ir_w
	movwf	timer3		;save the value
	movwf	timer2
pulse_loop
	bsf		irout		;IR on
	movlw	0x02
	movwf	timer1
pulse1
	decfsz	timer1,F	;.2us of 26ms
	goto	pulse1		;.2us
	nop
	nop
	nop
	bcf		irout		;IR off
	movlw	0x04
	movwf	timer1
pulse2
	decfsz	timer1,F
	goto	pulse2
	decfsz	timer2,F
	goto	pulse_loop	;loop w times

	movfw	timer3		;restore the value
	return

;wait w times 38 KHz - no output, but same code as above to get same timing
wait_ir_w
	movwf	timer3		;save the value
	movwf	timer2
wait_loop
	bcf		irout		;IR off
	movlw	0x02
	movwf	timer1
wait1
	decfsz	timer1,F
	goto	wait1
	nop
	nop
	nop
	nop
	bcf		irout		;IR off
	movlw	0x04
	movwf	timer1
wait2
	decfsz	timer1,F
	goto	wait2
	decfsz	timer2,F
	goto	wait_loop	;loop w times

	movfw	timer3		;restore the value
	return


	end