pwm.c

   1
   2 #include "pwm.h"
   3 #include "led.h"
   4 #include "util.h"
   5 #ifdef HAS_PWM_SUPPORT
   6
   7 void pwm_loop(){
   8 #ifdef PWM_ANIMATE
   9     pwm_animate();
  10 #endif//PWM_ANIMATE
  11 }
  12
  13 void pwm_setup(){
  14     //s/w "BCM"(<== "Binary Code Modulation") timer setup
  15     TCCR0A |= _BV(WGM01);
  16     TCCR0B |= _BV(CS02);
  17     TIMSK0 |= _BV(OCIE0A);
  18     OCR0A = 1;
  19     pwm_output_setup();
  20 }
  21
  22 ISR(TIMER0_COMPA_vect){
  23     pwm_unset_outputs();
  24     pwm_cycle<<=1;
  25     if(!pwm_cycle){
  26         pwm_cycle = 1;
  27     }
  28     uint8_t Q = 0;
  29     Q |= (pwm_val[0] & pwm_cycle)?1:0;
  30     Q |= (pwm_val[1] & pwm_cycle)?2:0;
  31     Q |= (pwm_val[2] & pwm_cycle)?4:0;
  32     Q |= (pwm_val[3] & pwm_cycle)?8:0;
  33     Q |= (pwm_val[4] & pwm_cycle)?16:0;
  34     Q |= (pwm_val[5] & pwm_cycle)?32:0;
  35     Q |= (pwm_val[6] & pwm_cycle)?64:0;
  36     Q |= (pwm_val[7] & pwm_cycle)?128:0;
  37     pwm_set_outputs(Q);
  38     TCNT0 = 0;
  39     OCR0A = pwm_cycle;
  40 }
  41
  42 uint8_t pwm_cycle = 1;
  43 uint8_t pwm_val[8];
  44
  45 rgb_value_t hsv_to_rgb(hsv_value_t k){
  46     //The following algorithm is loosely based on http://en.wikipedia.org/wiki/HSL_and_HSV#Converting_to_RGB
  47     uint16_t c_ = (uint16_t)k.v * (uint16_t)k.s;
  48     uint8_t c = c_>>8;
  49     uint8_t m = k.v - c;
  50     rgb_value_t ret = {0, 0, 0};
  51     uint8_t branch;
  52     uint8_t h_;
  53     if(k.h<128){
  54         if(k.h<85){
  55             if(k.h<43){
  56                 h_ = k.h;
  57                 branch = 0;
  58             }else{
  59                 h_ = 43-k.h;
  60                 branch = 1;
  61             }
  62         }else{
  63             h_ = k.h-128;
  64             branch = 2;
  65         }
  66     }else{
  67         if(k.h<171){
  68             h_ = 171-k.h;
  69             branch = 3;
  70         }else{
  71             if(k.h<213){
  72                 h_ = k.h-171;
  73                 branch = 4;
  74             }else{
  75                 h_ = 255-k.h;
  76                 branch = 5;
  77             }
  78         }
  79     }
  80     uint16_t x_ = c * (uint16_t)h_;
  81     uint8_t x = x_>>8;
  82     switch(branch){
  83         case 0:
  84             ret.r += c;
  85             ret.g += x;
  86             break;
  87         case 1:
  88             ret.r += x;
  89             ret.g += c;
  90             break;
  91         case 2:
  92             ret.g += c;
  93             ret.b += x;
  94             break;
  95         case 3:
  96             ret.g += x;
  97             ret.b += c;
  98             break;
  99         case 4:
 100             ret.r += x;
 101             ret.b += c;
 102             break;
 103         case 5:
 104             ret.r += c;
 105             ret.b += x;
 106             break;
 107     }
 108     return ret;
 109 }
 110
 111 #else//HAS_PWM_SUPPORT
 112
 113 void pwm_setup(){}
 114 void pwm_loop(){}
 115
 116 #endif//HAS_PWM_SUPPORT