pwm.rar_Gabriel

;==================================================================== ; Main.asm file generated by New Project wizard ; ; Created: Sat May 23 2015 ; Processor: 80C31 ; Compiler: ASEM-51 (Proteus) ;==================================================================== $NOMOD51 $INCLUDE (8051.MCU) ;==================================================================== ; DEFINITIONS ;==================================================================== ;==================================================================== ; VARIABLES ;==================================================================== LOWDUTYCYCLE EQU 0Bh; HIGHDUTYCYCLE EQU 0Ah; FLAGCYCLE bit 0E.1; PWMPIN bit P1.0; PWM output pin ;==================================================================== ; RESET and INTERRUPT VECTORS ;==================================================================== ; Reset Vector org 0000h jmp Start org 0008h jmp TIMER_0_INTERRUPT ;==================================================================== ; CODE SEGMENT ;==================================================================== org 0100h Start: ; Write your code here Loop: jmp Loop ;==================================================================== ; TIMER_0_INTERRUPT ;==================================================================== TIMER_0_INTERRUPT: JB PWM_FLAG, HIGH_DONE LOW_DONE: ; cycle so Jump to HIGH_DONE SETB PWM_FLAG ; Make PWM_FLAG=1 to indicate start of high section SETB PWMPIN ; Make PWM output pin High call updateHighCycle ;CLR TF0 ; Clear the Timer 0 interrupt flag RETI ; Return from Interrupt to where ; the program came from HIGH_DONE: CLR PWM_FLAG ; Make PWM_FLAG=0 to indicate start of low section CLR PWMPIN ; Make PWM output pin low call updateLowCycle ;CLR TF0 ; Clear the Timer 0 interrupt flag RETI ; Return from Interrupt to where PWM_STOP: CLR TR0 ; Stop timer to stop PWM RET ;==================================================================== ; PWM DUTY CYCLE ; The total duty cycle is 10ms -> TMOD 01, 16bits ; as a consequence : 10% -> 1ms ON 9ms OFF \ ; : 20% -> 2ms ON 8ms OFF ; : 30% -> 3ms ON 7ms OFF ; : 40% -> 4ms ON 6ms OFF ; : 50% -> 5ms ON 5ms OFF ;==================================================================== updateHighCycle : MOV TL0 , LOW(65535 - HIGHDUTYCYCLE) MOV TH0 , HIGH(65535 - HIGHDUTYCYCLE) RET updateLowCycle : MOV TL0 , LOW(65535 - LOWDUTYCYCLE) MOV TH0 , HIGH(65535 - LOWDUTYCYCLE) RET ;==================================================================== END