[PIC] Problem in NEC IR Decoding in PIC12F675

Code C - [expand]
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
/* 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;
      }
    }
  }
}