embedded rookie

pwm.c

enum{off, on, pwm}
sbit pwmOut = P0^1;
const int pwmValue=96;//120*0.8, which means 80% dutycycle

void PWM_Init(void);
void PWM(uint8_t status);

void PWM_Init(){
  T3YH=0x78;// 0-120 pieces
  T3YL=0x00;
  
  T3M=0xF0;  // enable PWM function, also the rate of timer is fosc/1
  IEN2=0x02; // Enable T3 interrupt & clear T3F
  //..some setting below
}

void PWM(uint8_t status){
  switch(status){
    case off:
      T3M=0x00;//disable pwm
      pwmOut=0;//gpio status low
    break;
    case on:
      T3M=0x00;
      pwmOut=1;
    break;
    case pwm:
      T3M = 0xF0;
      PWCH = 0x02;
      PW1DH = pwmValue;
      PW1DL = 0x00;
    break;
    default:
    break;
  }
}