firmware/pwmled.c

   1 #include <avr/io.h>
   2
   3 #include "lights.h"
   4
   5 static uint16_t pwm_vals[N_PWMLEDS*N_PWMLED_MODES];
   6 static uint16_t pwm_max[N_PWMLEDS] = {
   7         PWM_MAX/2,
   8         PWM_MAX - (PWM_MAX >> 4), // step-up
   9         PWM_MAX/2
  10 };
  11
  12 #define PWMLED2_TESTING_WITH_350MA_LED
  13
  14 #define SENSE_MOHM      33      /* 0.033 Ohm */
  15 #define MA_MOHM_GAIN_TO_ADC(ma, mohm, gain) (\
  16         ((unsigned long)(ma))*(mohm) /* voltage at sensing resistor in uV */ \
  17         /(1100000UL/gain/1024UL)     /* voltage of ADC reading == 1 */ \
  18 )
  19 static uint16_t adc_max[N_PWMLEDS] = {
  20         MA_MOHM_GAIN_TO_ADC( 400, SENSE_MOHM, 20),
  21         MA_MOHM_GAIN_TO_ADC(  30, SENSE_MOHM, 20),
  22 #ifdef PWMLED2_TESTING_WITH_350MA_LED
  23         MA_MOHM_GAIN_TO_ADC( 400, SENSE_MOHM,  1)
  24 #else
  25         MA_MOHM_GAIN_TO_ADC(2500, SENSE_MOHM,  1)
  26 #endif
  27 };
  28 static uint16_t adc_vals[N_PWMLEDS*N_PWMLED_MODES] = {
  29         /* pwmled0 */
  30         MA_MOHM_GAIN_TO_ADC(  20, SENSE_MOHM, 20),
  31         MA_MOHM_GAIN_TO_ADC(  50, SENSE_MOHM, 20),
  32         MA_MOHM_GAIN_TO_ADC( 100, SENSE_MOHM, 20),
  33         MA_MOHM_GAIN_TO_ADC( 350, SENSE_MOHM, 20),
  34         /* pwmled1 */
  35         MA_MOHM_GAIN_TO_ADC(   5, SENSE_MOHM, 20),
  36         MA_MOHM_GAIN_TO_ADC(  12, SENSE_MOHM, 20),
  37         MA_MOHM_GAIN_TO_ADC(  16, SENSE_MOHM, 20),
  38         MA_MOHM_GAIN_TO_ADC(  20, SENSE_MOHM, 20),
  39         /* pwmled2 */
  40 #ifdef PWMLED2_TESTING_WITH_350MA_LED
  41         MA_MOHM_GAIN_TO_ADC( 100, SENSE_MOHM,  1),
  42         MA_MOHM_GAIN_TO_ADC( 140, SENSE_MOHM,  1),
  43         MA_MOHM_GAIN_TO_ADC( 250, SENSE_MOHM,  1),
  44         MA_MOHM_GAIN_TO_ADC( 350, SENSE_MOHM,  1),
  45 #else
  46         MA_MOHM_GAIN_TO_ADC( 150, SENSE_MOHM,  1),
  47         MA_MOHM_GAIN_TO_ADC( 350, SENSE_MOHM,  1),
  48         MA_MOHM_GAIN_TO_ADC( 700, SENSE_MOHM,  1),
  49         MA_MOHM_GAIN_TO_ADC(2400, SENSE_MOHM,  1),
  50 #endif
  51 };
  52
  53 // TODO: maybe convert this to bitmask to simplify pwmled_needs_adc() ?
  54 static unsigned char pwmled_state[N_PWMLEDS];
  55 #define ST_DISABLED 0
  56 #define ST_PROBING  1
  57 #define ST_OFF      2
  58 #define ST_ON       3
  59
  60 static unsigned char pwmled_mode[N_PWMLEDS];
  61 static unsigned char pwmled_mode_set[N_PWMLEDS];
  62
  63 static uint16_t pwm_probes[N_PWMLEDS];
  64 static int16_t differences[N_PWMLEDS];
  65
  66 static void start_probing(unsigned char n)
  67 {
  68         pwmled_state[n] = ST_PROBING;
  69         pwm_set(n, 0);
  70         pwm_probes[n] = 0;
  71 }
  72
  73 void pwmled_init()
  74 {
  75         unsigned char i;
  76
  77         for (i = 0; i < N_PWMLEDS*N_PWMLED_MODES; i++) {
  78                 pwm_vals[i] = 0;
  79                 pwmled_mode[i] = 0;
  80                 pwmled_mode_set[i] = 0;
  81         }
  82
  83         for (i = 0; i < N_PWMLEDS; i++) {
  84                 differences[i] = 0;
  85                 start_probing(i);
  86         }
  87 }
  88
  89 unsigned char pwmled_needs_adc(unsigned char n)
  90 {
  91         unsigned char st = pwmled_state[n];
  92         if (st == ST_PROBING || st == ST_ON)
  93                 return 1;
  94         else
  95                 return 0;
  96 }
  97
  98 unsigned char pwmled_enabled(unsigned char n)
  99 {
 100         unsigned char st = pwmled_state[n];
 101         if (st == ST_OFF || st == ST_ON)
 102                 return 1;
 103         else
 104                 return 0;
 105 }
 106
 107 void pwmled_set_mode(unsigned char n, unsigned char mode)
 108 {
 109         if (!pwmled_enabled(n))
 110                 return;
 111
 112 #if 0
 113         log_byte(0xF8);
 114         log_byte(n);
 115         log_byte(mode);
 116 #endif
 117         if (mode > 0 && mode <= N_PWMLED_MODES) {
 118                 uint16_t pwmval;
 119                 mode--;
 120                 pwmval = pwm_vals[n*N_PWMLED_MODES+mode];
 121                 pwm_set(n, pwmval);
 122 #if 0
 123                 log_byte(pwmval);
 124 #endif
 125                 pwmled_state[n] = ST_ON;
 126                 pwmled_mode[n] = mode;
 127                 pwmled_mode_set[n] = 1;
 128                 differences[n] = 0;
 129         } else {
 130                 pwm_off(n);
 131                 pwmled_state[n] = ST_OFF;
 132         }
 133 }
 134
 135 static void inline probing_adc(unsigned char n, uint16_t adcval)
 136 {
 137         unsigned char need_bigger = 0, i;
 138         uint16_t *pwm_p = &pwm_vals[n*N_PWMLED_MODES];
 139         uint16_t *adc_p = &adc_vals[n*N_PWMLED_MODES];
 140         uint16_t pwm = pwm_probes[n];
 141
 142 #if 0
 143         log_byte(0xF4);
 144         log_byte(n);
 145         log_word(adcval);
 146 #endif
 147
 148         if (adcval > adc_max[n] // Too high
 149                 || (pwm == 0 && adcval > 0) // non-zero voltage with zero PWM
 150                 ) {
 151                 pwm_off(n);
 152                 pwmled_state[n] = ST_DISABLED;
 153                 log_byte(0xF0);
 154                 log_byte(n);
 155                 log_word(adcval);
 156                 return;
 157         }
 158
 159         for (i = 0; i < N_PWMLED_MODES; i++, pwm_p++, adc_p++) {
 160                 uint16_t adc = *adc_p;
 161                 if (adc >= adcval) {
 162                         *pwm_p = pwm;
 163                         need_bigger = 1;
 164                 }
 165         }
 166
 167 #if 0
 168         if ((n == 1 && pwm > 0x35) || adcval != 0) {
 169                 log_byte(n);
 170                 log_byte(0xF3);
 171                 log_byte(pwm);
 172                 log_word(adcval);
 173         }
 174 #endif
 175
 176         if (!need_bigger) { // successfully probed
 177                 pwm_off(n);
 178                 // pwm_set(n, 0);
 179                 pwmled_state[n] = ST_OFF;
 180                 log_byte(0xF1);
 181                 log_byte(n);
 182
 183                 return;
 184         }
 185
 186         if (pwm >= pwm_max[n]) { // over the maximum!
 187                 pwm_off(n);
 188                 pwmled_state[n] = ST_DISABLED;
 189                 log_byte(0xF2);
 190                 log_byte(n);
 191                 // pwm_set(n, 0);
 192                 return;
 193         }
 194
 195         // try to increase
 196         pwm++;
 197         pwm_probes[n] = pwm;
 198         pwm_set(n, pwm);
 199 }
 200
 201 // Feedback loop
 202 static void inline on_adc(unsigned char n, uint16_t adcval)
 203 {
 204         unsigned char mode = pwmled_mode[n];
 205         uint16_t adc_exp   =  adc_vals[n*N_PWMLED_MODES+mode];
 206         uint16_t *pwm_p    = &pwm_vals[n*N_PWMLED_MODES+mode];
 207         int16_t old_pwm    = *pwm_p;
 208         int16_t new_pwm    = old_pwm;
 209
 210 #if 0
 211         log_byte(0xF5);
 212         log_byte(n);
 213         log_word(adcval);
 214 #endif
 215
 216
 217         if (pwmled_mode_set[n]) { // ignore the first reading
 218                 pwmled_mode_set[n] = 0;
 219                 return;
 220         }
 221
 222         differences[n] += adcval;
 223         differences[n] -= adc_exp;
 224
 225         if (differences[n] > 16)
 226                 new_pwm -= 2;
 227         else if (differences[n] > 4)
 228                 new_pwm--;
 229         else if (differences[n] < -16)
 230                 new_pwm += 2;
 231         else if (differences[n] < -4)
 232                 new_pwm++;
 233         // new_pwm -= differences[n] >> 3;
 234
 235         if (new_pwm == old_pwm)
 236                 return;
 237
 238         differences[n] = 0;
 239
 240         if (new_pwm > (int16_t)pwm_max[n]) {
 241                 // FIXME: disconnected?
 242                 new_pwm = pwm_max[n];
 243         }
 244
 245         if (new_pwm < 1) {
 246                 // FIXME: short-circuit?
 247                 new_pwm = 1;
 248         }
 249
 250         *pwm_p = new_pwm;
 251         pwm_set(n, new_pwm);
 252
 253         if (jiffies > 500 && n == 1) {
 254                 log_byte(adcval & 0xFF);
 255                 log_byte(new_pwm);
 256         }
 257 }
 258
 259 void pwmled_adc(unsigned char n, uint16_t adcval)
 260 {
 261         unsigned char i, probing;
 262
 263         switch (pwmled_state[n]) {
 264         case ST_PROBING:
 265                 probing_adc(n, adcval);
 266 #if 1
 267                 probing = 0;
 268                 for (i = 0; i < N_PWMLEDS; i++)
 269                         if (pwmled_state[i] == ST_PROBING)
 270                                 probing = 1;
 271
 272                 if (!probing) {
 273                         for (i = 0; i < N_PWMLEDS; i++)
 274                                 log_byte(pwmled_state[i]);
 275
 276                         for (i = 0; i < N_PWMLEDS*N_PWMLED_MODES; i++)
 277                                 log_word(pwm_vals[i]);
 278                         log_flush();
 279                         log_set_state(4);
 280                 }
 281 #endif
 282
 283                 return;
 284         case ST_ON:
 285                 on_adc(n, adcval);
 286                 return;
 287         // WTF am I doing in this function then? Maybe recently switched off?
 288         }
 289 }