MikroElektronika books

Example 6 – Realization of pulse width modulation

The example shows the realization of continuously varying pulse width modulation (PWM). The continously modulated output is on the PORTE.0 pin which is monitored by a LED diode. The realization is carried out by using the mikroC compiler for dsPIC30F microcontrollers. Fig. 13-6 shows the electric diagram of the realized continuous PWM of a LED diode connected to PORTE.0.

dspic-microcontrollers-programming-in-c-chapter-13-image-6

Fig. 13-6 The electric diagram of the realized continuous PWM of a LED diode connected to PORTE.0.

unsigned int i;

unsigned int duty_50;

void main(){
 ADPCFG = 0xFFFF;
 PORTB = 0xAAAA;
 TRISB = 0;
 Delay_ms(1000);

 duty_50 = Pwm_Mc_Init(5000,1,0x01,0); // Pwm_Mc_Init returns 50% of the duty
 Pwm_Mc_Set_Duty(i = duty_50,1);
 Pwm_Mc_Start();

 do
 {
 i--;
 Pwm_Mc_Set_Duty(i,1);
 Delay_ms(1);
 if (i == 0)
 i = duty_50 * 2 - 1; // Let us not allow overflow
 PORTB = i;
 }
 while(1);
}//~