firmware/pwmled.c

   1 #include <avr/io.h>
   2
   3 #include "lights.h"
   4
   5 typedef struct {
   6         uint16_t target, pwm;
   7         int16_t err_sum;
   8         unsigned char mode, state;
   9         union {
  10                 unsigned char probe_steady, mode_changed;
  11         };
  12         uint16_t mode_pwm[N_PWMLED_MODES];
  13         int16_t err_sums[N_PWMLED_MODES];
  14         unsigned char modes_not_yet_stable;
  15 } pwmled_t;
  16
  17 pwmled_t pwmleds[N_PWMLEDS];
  18
  19 /*
  20  * Mode stabilization:
  21  * when changing brightness via pwmled_set_brightness() below,
  22  * we want to converge to the target value as fast as possible. Also,
  23  * we would like to somehow initialize the mode 3, which is used as
  24  * "mode 2 + other PWMLED on". So after the brightness is set,
  25  * we also set pwmleds[n].modes_not_yet_stable to MODE_STABILIZATION_TIME.
  26  * When modes_not_yet_stable is non-zero, we allow only mode 2 to be set
  27  * regardless of what is fed to pwmled_set_mode. We will then converge
  28  * to the target value of mode 2 only, and after MODE_STABILIZATION_TIME
  29  * ADC measurements, we copy the mode_pwm value to all other modes.
  30  * Only then it is allowed to set the other modes.
  31  */
  32 #define MODE_STABILIZATION_TIME (2*16)  // two seconds worth of measurements
  33
  34 #define PWMLED2_TESTING_WITH_350MA_LED
  35
  36 #define SENSE_MOHM      33      /* 0.033 Ohm */
  37 /*
  38  * Voltage in uV at ADC reading == 1 is 1100/gain/1024
  39  * ADC module returns sum of 1 << PWMLED_ADC_SHIFT measurements
  40  * Voltage in uV measured is current in mA * sense resistance in mOhm
  41  */
  42 #define MA_GAIN_TO_ADC(ma, gain) ((uint16_t) \
  43         ((uint32_t)(ma) \
  44         * (SENSE_MOHM) \
  45         * (1 << (PWMLED_ADC_SHIFT)) \
  46         * 1024 \
  47         / (1100000/(gain))))
  48
  49 static uint16_t adc_max[N_PWMLEDS] = {
  50 #ifdef TESTING_FW
  51         MA_GAIN_TO_ADC( 400, 20),
  52         MA_GAIN_TO_ADC(  30, 20),
  53         MA_GAIN_TO_ADC( 800,  1)
  54 #else
  55         MA_GAIN_TO_ADC( 900, 20),
  56         MA_GAIN_TO_ADC(  30, 20),
  57         MA_GAIN_TO_ADC(2500,  1)
  58 #endif
  59 };
  60
  61 static uint16_t adc_targets_0[] = {
  62         MA_GAIN_TO_ADC(  50, 20),
  63         MA_GAIN_TO_ADC(  80, 20),
  64         MA_GAIN_TO_ADC( 160, 20),
  65         MA_GAIN_TO_ADC( 350, 20),
  66 };
  67
  68 static uint16_t adc_targets_1[] = {
  69         MA_GAIN_TO_ADC(   5, 20),
  70         MA_GAIN_TO_ADC(  10, 20),
  71         MA_GAIN_TO_ADC(  20, 20),
  72 };
  73
  74 static uint16_t adc_targets_2[] = {
  75 #ifdef TESTING_FW
  76         MA_GAIN_TO_ADC( 120,  1),
  77         MA_GAIN_TO_ADC( 160,  1),
  78         MA_GAIN_TO_ADC( 240,  1),
  79         MA_GAIN_TO_ADC( 320,  1),
  80         MA_GAIN_TO_ADC( 460,  1),
  81 #else
  82         MA_GAIN_TO_ADC( 150,  1),
  83         MA_GAIN_TO_ADC( 300,  1),
  84         MA_GAIN_TO_ADC( 500,  1),
  85         MA_GAIN_TO_ADC( 700,  1),
  86         MA_GAIN_TO_ADC(1500,  1),
  87         MA_GAIN_TO_ADC(2500,  1),
  88 #endif
  89 };
  90
  91 static uint16_t adc_vals[N_PWMLEDS*N_PWMLED_MODES];
  92
  93 #define ST_DISABLED 0
  94 #define ST_OFF      1
  95 #define ST_PROBING  2
  96 #define ST_ON       3
  97 // The above are constructed so that the following work:
  98 #define ST_IS_ON(s)     ((s) & 0x02)
  99 #define ST_CAN_SET_MODE(s)      ((s) & 0x01)
 100
 101 void init_pwmled()
 102 {
 103         unsigned char i, j;
 104
 105         for (i = 0; i < N_PWMLEDS; i++) {
 106                 pwmled_t *led = pwmleds + i;
 107                 led->err_sum = 0;
 108                 led->target = adc_vals[i*N_PWMLED_MODES];
 109                 led->mode = 1;
 110                 led->probe_steady = 0;
 111                 led->state = ST_OFF;
 112                 led->pwm = 1;
 113                 pwm_set(i, led->pwm);
 114
 115                 for (j = 0; j < N_PWMLED_MODES; j++) {
 116                         led->mode_pwm[j] = 0;
 117                         led->err_sums[j] = 0;
 118                 }
 119         }
 120
 121         pwmled_set_brightness(PWMLED_BRIGHTNESS(0, 2, 1, 0, 2));
 122 }
 123
 124 void pwmled_set_mode(unsigned char n, unsigned char mode)
 125 {
 126         pwmled_t *led = pwmleds + n;
 127
 128         if (!ST_CAN_SET_MODE(led->state))
 129                 return;
 130
 131         if (led->mode) { // save the previous state
 132                 led->mode_pwm[led->mode - 1] = led->pwm;
 133                 led->err_sums[led->mode - 1] = led->err_sum;
 134         }
 135
 136         led->mode = mode;
 137
 138         if (mode > 0 && mode <= N_PWMLED_MODES) {
 139                 if (led->modes_not_yet_stable) // only mode 2 when !stable
 140                         mode = 2;
 141                 led->target = adc_vals[n*N_PWMLED_MODES + mode - 1];
 142                 led->state = ST_ON;
 143                 led->pwm = led->mode_pwm[mode - 1];
 144                 led->err_sum = led->err_sums[mode - 1];
 145                 led->mode_changed = 1;
 146                 pwm_set(n, led->pwm);
 147         } else {
 148                 led->state = ST_OFF;
 149                 pwm_off(n);
 150         }
 151 }
 152
 153 #define CHECK_BRIGHTNESS(var, expr, array) \
 154         do { \
 155                 (var) = (expr); \
 156                 if ((var) >= sizeof(array)/sizeof(array[0])) \
 157                         (var) = sizeof(array)/sizeof(array[0]) - 1; \
 158         } while (0)
 159
 160 void pwmled_set_brightness(uint16_t brightness)
 161 {
 162         unsigned char i;
 163
 164         CHECK_BRIGHTNESS(i, brightness & 0x7, adc_targets_0);
 165         adc_vals[0] = adc_targets_0[i];
 166         CHECK_BRIGHTNESS(i, (brightness >> 3) & 0x7, adc_targets_0);
 167         if (adc_vals[1] != adc_targets_0[i]) {
 168                 adc_vals[1] = adc_targets_0[i];
 169                 pwmleds[0].modes_not_yet_stable = MODE_STABILIZATION_TIME;
 170         }
 171         adc_vals[2] = adc_vals[1];
 172
 173         CHECK_BRIGHTNESS(i, (brightness >> 6) & 0x7, adc_targets_1);
 174         // we use only one mode, so no modes_not_yet_stable handling here
 175         adc_vals[3] = adc_targets_1[i];
 176         adc_vals[4] = adc_vals[3];
 177         adc_vals[5] = adc_vals[3];
 178
 179         CHECK_BRIGHTNESS(i, (brightness >> 9) & 0x7, adc_targets_2);
 180         adc_vals[6] = adc_targets_2[i];
 181         CHECK_BRIGHTNESS(i, (brightness >> 12) & 0x7, adc_targets_2);
 182         if (adc_vals[7] != adc_targets_2[i]) {
 183                 adc_vals[7] = adc_targets_2[i];
 184                 pwmleds[2].modes_not_yet_stable = MODE_STABILIZATION_TIME;
 185         }
 186         adc_vals[8] = adc_vals[7];
 187
 188         for (i = 0; i < N_PWMLEDS; i++) {
 189                 pwmleds[i].err_sum = 0;
 190                 pwmled_set_mode(i, pwmleds[i].mode);
 191         }
 192 }
 193
 194 #define PWMLED_PROBE_STEADY_COUNT 10
 195
 196 static inline unsigned char pwmled_probed_ok(unsigned char n, uint16_t old_pwm)
 197 {
 198         pwmled_t *led = pwmleds + n;
 199
 200         if (led->pwm == old_pwm) {
 201                 if (led->probe_steady < PWMLED_PROBE_STEADY_COUNT)
 202                         led->probe_steady++;
 203         } else {
 204                 led->probe_steady = 0;
 205         }
 206
 207         if (led->probe_steady < PWMLED_PROBE_STEADY_COUNT
 208                 && old_pwm <= led->pwm)
 209                 return 0;
 210
 211         // probed OK
 212         led->mode_pwm[led->mode - 1] = led->pwm;
 213         led->err_sums[led->mode - 1] = 0;
 214
 215         // next mode to probe?
 216         if (led->mode < N_PWMLED_MODES) {
 217                 led->probe_steady = 0;
 218                 led->err_sum = 0;
 219
 220                 led->mode++;
 221                 led->target = adc_vals[n*N_PWMLED_MODES+led->mode-1];
 222
 223                 return 0;
 224         } else {
 225                 unsigned char i;
 226
 227                 led->state = ST_OFF;
 228                 pwm_off(n);
 229
 230                 log_byte(0xF0);
 231                 log_byte(n);
 232                 log_word(jiffies);
 233
 234                 for (i = 0; i < N_PWMLED_MODES; i++)
 235                         log_word(led->mode_pwm[i]);
 236
 237                 log_flush();
 238
 239                 pattern_reload();
 240
 241                 return 1;
 242         }
 243 }
 244
 245 static inline void pwmled_err(unsigned char n)
 246 {
 247         pwmleds[n].state = ST_DISABLED;
 248         pwm_off(n);
 249
 250         log_byte(0xF1);
 251         log_byte(n);
 252         log_word(jiffies);
 253         log_flush();
 254
 255         switch (n) {
 256         case 0: err_flags.err_pwmled0 = 1; break;
 257         case 1: err_flags.err_pwmled1 = 1; break;
 258         case 2: err_flags.err_pwmled2 = 1; break;
 259         }
 260 }
 261
 262
 263 void pwmled_adc(unsigned char n, uint16_t adcval)
 264 {
 265         pwmled_t *led = pwmleds + n;
 266         uint16_t old_pwm;
 267         int32_t sum;
 268         unsigned char shift;
 269
 270         if (!ST_IS_ON(led->state))
 271                 return;
 272
 273         if (led->state == ST_ON && led->mode_changed) {
 274                 led->mode_changed--;
 275                 return;
 276         }
 277         // FIXME: test for maximum adcval value (adc_max[n])
 278
 279         old_pwm = led->pwm;
 280
 281         // shift = led->state == ST_PROBING ? 3 : 8;
 282         shift = 3;
 283
 284         sum = ((int32_t)led->pwm << shift)
 285                 + led->err_sum + led->target - adcval;
 286
 287         if (sum < 0)
 288                 sum = 0;
 289
 290         led->pwm = sum >> shift;
 291         sum -= led->pwm << shift;
 292         led->err_sum = sum;
 293
 294         if (led->pwm >= PWM_MAX
 295                 || (n == 1 && led->pwm > PWM_MAX/2 && adcval < 0x08)) {
 296                 pwmled_err(n);
 297                 return;
 298         }
 299
 300         if (led->state == ST_PROBING)
 301                 if (pwmled_probed_ok(n, old_pwm))
 302                         return;
 303
 304         if (led->modes_not_yet_stable) {
 305                 if (!--led->modes_not_yet_stable) {
 306                         // reached stability, copy mode 2 to mode 3 (-1)
 307                         led->mode_pwm[0] = led->pwm;
 308                         led->mode_pwm[2] = led->pwm;
 309                         led->err_sums[0] = 0;
 310                         led->err_sums[2] = 0;
 311                 }
 312         }
 313
 314         if (led->pwm == old_pwm)
 315                 return;
 316
 317         pwm_set(n, led->pwm);
 318 }
 319