Quick and Easy Wireless

The Software
           The software has two main portions:

    -CCP1/2 Interrupt Routines
    -Main Switch Routine



The Low and High Priority interrupts are assigned to CCP1 and CCP2 and every time an interrupt is triggered a timer value is read and then reset. This allows for real-time tracking of the input signal and output to the LED and motor. Below is the interrupt routines for the CCP modules capturing input signals. Every time there is a rising or falling edge, the interrupt is triggered, timer value read and cleared and the capture mode switched between rising/falling edge captures.

Interrupt Handler Code

void InterruptHandlerHigh()
{
     if(PIR1bits.CCP1IF){
          timer1_value = ReadTimer1();
          WriteTimer1( 0x0000 );
          PIR1bits.CCP1IF = 0;
          //Switch Capture Rising/Falling Edge
          if(CCP1CONbits.CCP1M0 == 1)
               CCP1CONbits.CCP1M0 = 0;
          else
               CCP1CONbits.CCP1M0 = 1;
     }
     else if(PIR1bits.TMR1IF){
          PIR1bits.TMR1IF = 0;
     }
INTCONbits.GIEH = 1;
return;
}
void InterruptHandlerLow()
{
     if(PIR2bits.CCP2IF){
          timer0_value = ReadTimer0();
          WriteTimer0( 0x0000 );
          PIR2bits.CCP2IF = 0;
          //Switch Capture Rising/Falling Edge
          if(CCP2CONbits.CCP2M0 == 1)
               CCP2CONbits.CCP2M0 = 0;
          else
               CCP2CONbits.CCP2M0 = 1;
     }
     else if(INTCONbits.TMR0IF){
          INTCONbits.TMR0IF = 0;
     }
INTCONbits.GIEL = 1;
return;
}

           The next set of code is where the main function evaluates and outputs according to the current input values. Since the input values can be constantly changing, the main function needs to act on these changes and update the output.

LED and Motor Input/Output Control

     ..
     ...
     //Channl 0 Control
     if(timer1_value > 0x03E8 && timer1_value < 0x07D0)
          temp = (timer1_value>>5)-30;

     //Channel 1 Control
     //Use a Switch Statement next time Chris...>_<<br />      if(timer0_value < 0x03E8){
          forward = 0;
          reverse = 0;
     }
     else if(timer0_value > 0x03E8 && timer0_value <= 0x0430){
          forward = 0;
          reverse = 55;
     }
     ..
     ...
     ...
     //LED Dimmer Control
     if(cnt < temp)
          PORTA = 0x01;
     else
          PORTA = 0x00;
     //Move Motor Forward
     if(forward > 0 && reverse == 0){
          if(cnt < forward){
               PORTB = PORTB ^ 0b11111110;
     }
     else{
               PORTB = 0x00;
          }
     }
     //Move Motor Reverse
     else if(reverse > 0 && forward == 0){
          if(cnt < reverse)
               PORTB = PORTB ^ 0b11111101;
          else
               PORTB = 0x00;
     }
     else
           PORTB = PORTB & 0b00000000;
     if(cnt == 60)
          cnt = 0;
     cnt++;
     ...
     ..

           This system is very much a 2 way input, 2 way output straight forward system. The interrupt routines allow for us to act in real time on signal input from the receiver and to create the output we desire. The LED brightness varies depending on the CCP1, timer1 value. The motor controller forward and reverse are set at different values depending upon the CCP2, timer0 value.