I'm using PIC12F675 with internal OSC running @ 4MHz. I'm using MikroC Pro compiler version 6.6.2.

To Decode NEC protocol, I'm not using Timer or Interrupt. I used delay command to make the code as simple as possible with time-out property and the code checks the IR signal with resolution of 50µs.

My program is working fine with PIC16F877A which running with external OSC @ 16MHz. But when I using the same program for PIC12F675 its not working for me.

I have disabled Pull-ups and MCLR pin function for PIC12F675. And using the GP3 pin as the input for IR receiver.

I'm using the example from here.

Below is my program. Please, can someone help me to solve this problem for PIC12F675?

Thank you

Chayan

/* Pin Configuration */
#define IR_PIN                RB0_bit       /**< IR Signal Reception Pin.*/
#define LED_PIN               RC5_bit

unsigned long ir_code;
unsigned int address;
unsigned short command, inv_command;


short nec_remote_read() {

unsigned long count = 0, i;
// Check 9ms pulse (remote control sends logic high)
while ((IR_PIN == 0) && (count < 190)) {
count++;
delay_us(50);
}
if ( (count > 189) || (count < 120))     // NEC protocol?
return 0;

count = 0;
// Check 4.5ms space (remote control sends logic low)
while (IR_PIN && (count < 95)) {
count++;
delay_us(50);
}
if ( (count > 94) || (count < 30))       // NEC protocol?
return 0;

// Read code message (32-bit)
for (i = 0; i < 32; i++) {
count = 0;
while ((IR_PIN == 0) && (count < 14)) {
  count++;
  delay_us(50);
}
if ( (count > 13) || (count < 2))     // NEC protocol?
  return 0;

count = 0;
while (IR_PIN && (count < 40)) {
  count++;
  delay_us(50);
}
if ( (count > 39) || (count < 4))     // NEC protocol?
  return 0;

if ( count > 20)                      // If space width > 1ms
  ir_code |= 1ul << (31 - i);         // Write 1 to bit (31 - i)
else                                  // If space width < 1ms
  ir_code &= ~(1ul << (31 - i));      // Write 0 to bit (31 - i)
}
return 1;
}

void main()
{
TRISB0_bit = 1;
TRISC5_bit = 0;

while(1) { //Loop executed infinite times

//while (IR_PIN);                //Wait until IR pin falls
if (nec_remote_read()) {
address = ir_code >> 16;
command = ir_code >> 8;
inv_command = ir_code;

switch(command){
  case 0x48:
  LED_PIN = 1;
  break;
  case 0x80:
  LED_PIN = 0;
  break;
   }
  }
 }
}