Interfacing PIC16F877A with L298 to control a Two 12V DC Motor by PWM.

[Ishah]

Hi,

Im using a PIC16F877A with L298 to control a 12V DC Motor.
I want to control the speed of the motor by PWM.
I already draw a circuit with external OSC 20MHz and some MicroC code.
Can anyone checking on it and gives
some guidelines or code (MicroC) on how to program a PIC16F877A.

Thanks.

unsigned short current_duty, old_duty, current_duty1, old_duty1;

//define motor1 ports
sbit motor1a at RD0_bit;
sbit motor1b at RD1_bit;


//define motor2 ports
sbit motor2a at RD2_bit;
sbit motor2b at RD3_bit;


//define controller 1 ports
#define increase PORTB.F1
#define decrease PORTB.F0
#define forward PORTB.F2
#define reverse PORTB.F3

void InitMain() {
  TRISB = 0XFF;       // configure PORTB pins as input
  PORTB = 0;
  TRISD = 0X00;        // configure PORTD pins as output
  PORTD = 0;
  TRISC = 0XFF;       // configure PORTC pins as input
  PORTC = 1;
  
  CMCON=0X07; //      or CMCON register = 0X00000111
  ADCON1=0X07; //     Configure ADCON1, or ADCON1=0X06;
  CCP1CON = 12;     //PWM mode = 0;


  PORTD = 255;        //100% PWM duty ratio
  TRISD = 255;
  
  PWM1_Init(5000);                    // Initialize PWM1 module at 5KHz
  PWM2_Init(5000);                    // Initialize PWM2 module at 5KHz
}

void main() {
  InitMain();
  current_duty  = 0X00;                 // initial value for current_duty
  current_duty1 = 0X00;                 // initial value for current_duty1

  PWM1_Start();                       // start PWM1
  PWM2_Start();                       // start PWM2
  PWM1_Set_Duty(current_duty);        // Set current duty for PWM1
  PWM2_Set_Duty(current_duty1);       // Set current duty for PWM2

  
while (1) {                         // endless loop
    
    if (forward == 1) {    // button on RB0 pressed
      motor1a  = 0;
      motor1b  = 1;    //Motor Forward
      Delay_ms(500);    //1 Second Delay
      current_duty++;                 // increment current_duty
      PWM1_Set_Duty(current_duty);
     }

    if (reverse == 1) {      // button on RB1 pressed
      motor1a  = 1;
      motor1b  = 0;     //Motor Reverse
      Delay_ms(30);     //1 Second Delay
      Delay_ms(40);
      current_duty--;                 // decrement current_duty
      PWM1_Set_Duty(current_duty);
     }

    if (increase == 1) {            // button on RB2 pressed
      Delay_ms(40);
      current_duty1++;                // increment current_duty1
      PWM2_Set_Duty(current_duty1);
     }

    if (decrease == 1) {                    // button on RB3 pressed
      Delay_ms(40);
      current_duty1--;                // decrement current_duty1
      PWM2_Set_Duty(current_duty1);
     }

    Delay_ms(5);                      // slow down change pace a little
  }
}

 

[Ishah]

When I simulate by using Proteus, nothing happen to my both DC motor. Its does not work.

I want my motor to be run forward and reverse movement, also when the user want to turn right, motor 1 will slow while motor 2 will going faster. It be vice verse when the user want to turn left.

Anyone can help me on the MicroC code.