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[PIC] Trouble generating PWM using Pic 16F1503

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rocky79

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I am trying to send a PWM signal on PortC5 (PWM1) using the latest CCS compiler(5.026).
This is the manual method of sending a PWM and it doesn't seem to be working.
I have followed the PWM Setup and generation on page 221 of PIC16f1503 datasheet. I just couldn't get it to work. Anyone have anyidea what else I should be doing?



Code:
#include <16F1503.h>
#fuses   INTRC_IO, NOWDT, NOPROTECT, NOMCLR
#use     delay(clock = 4000000)
#USE     FAST_IO (C)
//----------------------------------- ---------
//GPIO BIT ASSIGNMENT FOR I/O REGISTERS PORT A
//--------------------------------------------
//address of the TRISIO registe
#byte   TRISC = getenv("SFR:TRISC") 
#byte   PORTC = getenv("SFR:PORTC")
#bit    PORTC_1=PORTC.1

#word   ANSELC = getenv("SFR:ANSELC")   

// setting up PWM parameters
#byte PR2= getenv("SFR:PR2")
#byte T2CON=getenv("SFR:T2CON")

#word PWM1CON= getenv("SFR:PWM1CON") 
#word PWM1DCH=getenv("SFR:PWM1DCH") 
#word PWM1DCL=getenv("SFR:PWM1DCL") 
#bit  PWM1DCL_7=PWM1DCL.7
#bit  PWM1DCL_6=PWM1DCL.6       
                            

#byte PIR1=getenv("SFR:PIR1")  
#bit PIR1_1=PIR1.1           

int16 duty;
#bit duty_0=duty.0
#bit duty_1=duty.1

void pwm(int16 value);

void main()
{
int16 i;
//----------------------manual PWM config--------------------------------
   //SET ALL PORT C PIN DIGITAL
   ANSELC=0x0;
   //Disable the PWM pin (CCPx) output driver(s) by
   //setting the associated TRIS bit(s) to INPUT
   //TRISC= 0b00111111;                        
   //TRISC= 0x0;//OUTPUT
   //Clear the PWM1CON register.
   PWM1CON=0x0; 
   //Load the PR2 register with the PWM period value.
   PR2=255; // 255hz   
   //Clear the PWMxDCH register and bits <7:6> of
   //the PWMxDCL register.
   //Load the CCPRxL register and the DCxBx bits of
   //the CCPxCON register, with the PWM duty cycle
   //value.
   duty = 0;                   // set duty cycle to 0
   //Clear the PWMxDCH register and bits <7:6> of
   //the PWMxDCL register.
   PWM1DCH=0x0;
   PWM1DCL_6 = 0;         // Store duty to registers as
   PWM1DCL_7 = 0;         // a 10-bit word
    delay_ms(5);
   //Configure and start Timer2:
   //clear the TMR21F interrupt flag bit of PIR1 register
   PIR1_1=0;
   delay_ms(5);
   //START TIMER2 Set prescaler(64) AND POSTSCALER
   T2CON=0b00000111;
   //-----------------------------------------------
   //Configure the T2CKPS bits of the T2CON register
   //with the Timer2 prescale value.
   //-----------------------------------------------
   //0000 =1:1 Postscaler
   //1    = Timer2 is on                           
   //10 = Prescaler is 16
   //11 = Prescaler is 64
   //------------------------------------------------
   //------------------------------------------------
   //Enable PWM output pin and wait until Timer2
   //overflows, TMR2IF bit of the PIR1 register is set.
   //------------------------------------------------
   PWM1CON=0b10000000; 

   wait_for_TMR2IF:            
   if (PIR1_1 == 0)
     {
     goto wait_for_TMR2IF;
     }    
   //Enable the PWMx pin output driver(s) by clearing
   //the associated TRIS bit(s).
   TRISC=0x0;
   //and setting PWM1OE bit of the PWM1CON registeR
   PWM1CON=0b11000000;
   //SET A PWM VALUES To START
   duty=0;
   PWM1DCL_6 = duty_0;    // Store duty to registers as
   PWM1DCL_7 = duty_1;    // a 10-bit word
   PWM1DCH = duty >> 2;    // store the remaining low byte}
                
    while(1) 
    {
 
    for(i=0;i<1020;++i)
        {
        //Output a PWM wave
       //set_pwm1_duty(i);
       pwm(i);
       delay_ms(3);
        }
           
     }     
}

void pwm(int16 value)
{
   //int16 value;
   duty=value;
   PWM1DCL_6 = duty_0;    // Store duty to registers as
   PWM1DCL_7 = duty_1;    // a 10-bit word
   PWM1DCH = duty >> 2;    // store the remaining high byte}
}
 
Last edited:

No one has experienced this issue before on the 16F1503?

I usually have no issue in generating PWM, but this chip is giving me trouble.

I have followed the instructions in section" 22.1.9 SETUP FOR PWM OPERATION" one by one. Are there anything else that I need to set beside the instructions on the datasheet?
 

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