list p=pic16c54B, r=hex

			#include <p16c5x.inc>
			#define PWM_PORT    PORTA
			#define PWM_PIN     0

DutyCycle	EQU	0x09
Counter		EQU	0x0A
Period		EQU	0x0B

			ORG	0x00
Begin			call	Initialize_PWM
Main			call	PWM_Signal
			goto	Main

Initialize_PWM		clrf	PORTA		; reset PORTA
			movlw	b'00001110'
			tris	PORTA		; Set PWM pin for output
movlw	80
			movwf	DutyCycle	; initialize duty cycle
			movlw	FF
			movwf	Period		; initialize period register
			clrf	Counter		; reset counter
			bsf	PORTA, PWM_PIN	; set PWM signal to high
			retlw	0

PWM_Signal		incf	Counter,f 	; Increment the counter
			movf	DutyCycle,w
			subwf	Counter,w	; compare duty cycle against 
						; period
			btfss	STATUS,C	; Is period < duty cycle
			retlw	0		; duty cycle is greater than
						;period, therefore PWM signal
						; remains high

			bcf	PORTA,PWM_PIN		; time of duty cycle 
							;elapsed
			movf	Period,w		; compare the counter 
							;against the period
			subwf	Counter,w
			btfss	STATUS,Z		; if the counter == 
							; period,
			retlw	0			; period is not over
			clrf	Counter			; reset the counter
			bsf	PORTA, PWM_PIN		; Set PWM_Pin to high
			retlw	0

			ORG 	0x1FF
Reset			goto	Begin

			END