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Revision 812788aa

ID812788aa5bc592cf417de345fdd8a74933d7a0c8

Added by Thomas Mullins over 11 years ago

Moved some sensors to different timers

Most notably, change the ROS millisecond counter to share the BOM 38 kHz
timer instead of having its own. The range sensor and BOM rx will now
share timer 5, but they both have to be fixed for the higher F_CPU.

View differences:

scout_avr/src/bom.cpp
12 12 
 *   0: 1ms period
13 13 
 *  Signal:
14 14 
 *   38kHz pulse for 320us, then off for rest of time (680us or 1680us)
15 
 * BOM uses timer 4 for period timing, and timer 3 for 38kHz signal
15 
 * BOM uses timer 4 for period timing, and timer 0 for 38kHz signal
16 16 
 */
17 17 

  		




  18
  
  
    
#define TIME_KHZ(khz, prescale) (F_CPU / 1000 / (khz) / (prescale))


  		




  19
  18
  
    
#define TIME_MICROS(us, prescale) (F_CPU / 1000000 * (us) / (prescale))


  		




  20
  19
  
    

  		




  21
  20
  
    
typedef uint16_t sharp_msg_t;


  		




  ......




  52
  51
  
    
  return robot_id;


  		




  53
  52
  
    
}


  		




  54
  53
  
    

  		




  55
  
  
    
ISR(TIMER3_COMPA_vect) {


  		




  
  54
  
    
void bom_isr() {


  		




  56
  55
  
    
  if (out_high) {


  		




  57
  56
  
    
    BOM_EMIT ^= out_pin_mask;


  		




  58
  57
  
    
  }


  		




  ......




  62
  61
  
    
  out_high = 0;


  		




  63
  62
  
    
  out_pin_mask = 0;


  		




  64
  63
  
    
  


  		




  65
  
  
    
  // timer 3 mode CTC (clear timer on compare), TOP = OCRA


  		




  66
  
  
    
  TCCR3A = 0;


  		




  67
  
  
    
  TCCR3B = _BV(WGM32);


  		




  68
  
  
    
  TCCR3C = 0;


  		




  69
  
  
    
  


  		




  70
  
  
    
  // toggling at 38kHz * 2 gives 38kHz wave


  		




  71
  
  
    
  OCR3A = TIME_KHZ(38 * 2, 1);


  		




  72
  
  
    
  


  		




  73
  
  
    
  // enable interrupt


  		




  74
  
  
    
  TIMSK3 = _BV(OCIE3A);


  		




  75
  
  
    
  


  		




  76
  
  
    
  // start timer 3 at F_CPU, no prescaling


  		




  77
  
  
    
  TCCR3B |= _BV(CS30);


  		




  
  64
  
    
  // timer configuration now done in Atmega128rfa1.cpp


  		




  78
  65
  
    
}


  		




  79
  66
  
    

  		




  80
  67
  
    
static void start_38kHz_signal() {


  		




  ......




  92
  79
  
    
  // timer 4 mode CTC (clear timer on compare), TOP = OCRA


  		




  93
  80
  
    
  TCCR4A = 0;


  		




  94
  81
  
    
  TCCR4B = _BV(WGM42);


  		




  95
  
  
    
  TCCR3C = 0;


  		




  96
  82
  
    
  


  		




  97
  83
  
    
  // run interrupt immediately when timer started


  		




  98
  84
  
    
  OCR4A = 0;


  		




  ......




  166
  152
  
    
  if (is_rising) {


  		




  167
  153
  
    
    // TODO check 320us? or have 320us timeout on rising edge?


  		




  168
  154
  
    
  } else {


  		




  169
  
  
    
    // uses timer 1, assuming prescale 1/8


  		




  170
  
  
    
    // timer 1 is set up by range_init()


  		




  
  155
  
    
    // uses timer 5, assuming prescale 1/8


  		




  
  156
  
    
    // timer 5 is set up by range_init()


  		




  171
  157
  
    
    // this should be in units of microseconds


  		




  172
  
  
    
    int now = TCNT1 * (F_CPU / 1000000 / 8);


  		




  
  158
  
    
    int now = TCNT5 / (F_CPU / 8 / 1000000);


  		




  173
  159
  
    
    


  		




  174
  160
  
    
    if (rx->count) {


  		




  175
  161
  
    
      int diff = now - rx->last_time;


  		












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