Why is this PWM not working? (mikroC code)

[internetuser2k12]

Why this pwm is not working? Nothing appears on the oscilloscope.

mikroC Code

#define SW PORTA.F0

void main() {

     int speed_counter;
     TRISA = 0xFF;
     TRISC = 0x00;
     PORTA = 0x00;
     PORTC = 0x00;


     PWM1_Init(33000);
     PWM1_Start();
     speed_counter = 0;
     
     while(1) {
    
          if(SW == 1) {
                Delay_ms(20);
                if(SW == 1) {
                   speed_counter = speed_counter + 1;
                }
          }
     
          if(speed_counter > 4) {
               speed_counter = 0;
          }
     
          switch (speed_counter) {
                 case 0: {
                      PWM1_Set_Duty(0);
                      break;
                 }
          
                 case 1: {
                      PWM1_Set_Duty(64);
                      break;
                 }
          
                 case 2: {
                      PWM1_Set_Duty(127);
                      break;
                 }
          
                 case 3: {
                      PWM1_Set_Duty(192);
                      break;
                 }
          
                 case 4: {
                      PWM1_Set_Duty(255);
                      break;
                 }
          
                 default:
                         ;
          
          }
     }
}

 

[willis...]

re: Why this is not working?

Why this pwm is not working? Nothing appears on the oscilloscope.

mikroC Code

#define SW PORTA.F0

void main() {

     int speed_counter;
     TRISA = 0xFF;
     TRISC = 0x00;
     PORTA = 0x00;
     PORTC = 0x00;


     PWM1_Init(33000);
     PWM1_Start();
     speed_counter = 0;
     
     while(1) {
    
          if(SW == 1) {
                Delay_ms(20);
                if(SW == 1) {
                   speed_counter = speed_counter + 1;
                }
          }
     
          if(speed_counter > 4) {
               speed_counter = 0;
          }
     
          switch (speed_counter) {
                 case 0: {
                      PWM1_Set_Duty(0);
                      break;
                 }
          
                 case 1: {
                      PWM1_Set_Duty(64);
                      break;
                 }
          
                 case 2: {
                      PWM1_Set_Duty(127);
                      break;
                 }
          
                 case 3: {
                      PWM1_Set_Duty(192);
                      break;
                 }
          
                 case 4: {
                      PWM1_Set_Duty(255);
                      break;
                 }
          
                 default:
                         ;
          
          }
     }
}

Could you please provide the rest of the pertinent source code so that I can see your initialization functions. While the code above looks fine from what I could tell, there might be something that is not being initialized correctly.

Also, would it be possible for you to provide a .pdf of your schematic. Unfortunately I do not have a copy of OrCAD installed on my machine.

Regards,
Willis

 

[internetuser2k12]

re: Why this is not working?

There is no Initialization. I have posted the full code. All PWM things are done by the PWM library functions. That is a proteus .dsn file.

 

[numair_noor]

re: Why this is not working?

you must delete the last flower bracket. which is extra. and you must power on the microcontroller, thus, attach a logic state to the pin^1(Vpp) of pic microcontroller. and make it logic high.

#define SW PORTA.F0

void main() {

     int speed_counter;
     TRISA = 0xFF;
     TRISC = 0x00;
     PORTA = 0x00;
     PORTC = 0x00;


     PWM1_Init(33000);
     PWM1_Start();
     speed_counter = 0;

     while(1) 
          {

          if(SW == 1) 
                {
                   Delay_ms(20);
                   speed_counter = speed_counter + 1;
                }
          }

          if(speed_counter > 4) {
               speed_counter = 0;
          }

          switch (speed_counter) {
                 case 0: {
                      PWM1_Set_Duty(0);
                      break;
                 }

                 case 1: {
                      PWM1_Set_Duty(64);
                      break;
                 }

                 case 2: {
                      PWM1_Set_Duty(127);
                      break;
                 }

                 case 3: {
                      PWM1_Set_Duty(192);
                      break;
                 }

                 case 4: {
                      PWM1_Set_Duty(255);
                      break;
                 }

                 default:
                         ;

          }
     }

 

[internetuser2k12]

re: Why this is not working?

Yes. I did that too, but I don't get the pulses.

 

[numair_noor]

re: Why this is not working?

ok, what is your aim to do with that?
be specific in your question. what percentage of pulses do you need exactly?

 

[internetuser2k12]

Re: Why this is not working???????

I need 25%, 50% and 75% PWM Pulses. It is used to control the speed of motor. But in simulation the motor is running on its own without button being pressed.

I did the same circuit with PIC16F887 and it is working fine.

 

[g_shyam1682]

re: Why this is not working?

Hi friend

Check alternative function over Port A pin which is you had to use as a input.
There is one possibility, that you initialize speed_counter = 0; and if your input pin not working, your switch-case logic select case 0 where PWM duty cycle is 0. So you don't get any outpur.
So check your input port pin as well as for testing purpose initialize speed_counter = 1 or 2 or 3;

Best of luck.

 

[internetuser2k12]

Re: Why this is not working?

OK. Thanks It is working fine. The problem was with the switch.