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, probe_steps;
   9         uint16_t mode_pwm[N_PWMLED_MODES];
  10         int16_t err_sums[N_PWMLED_MODES];
  11 } pwmled_t;
  12
  13 pwmled_t pwmleds[N_PWMLEDS];
  14
  15 #define PWMLED2_TESTING_WITH_350MA_LED
  16
  17 #define SENSE_MOHM      33      /* 0.033 Ohm */
  18 #define MA_MOHM_GAIN_TO_ADC(ma, mohm, gain) (\
  19         ((unsigned long)(ma))*(mohm) /* voltage at sensing resistor in uV */ \
  20         /(1100000UL/gain/1024UL)     /* voltage of ADC reading == 1 */ \
  21 )
  22
  23 static uint16_t adc_max[N_PWMLEDS] = {
  24         MA_MOHM_GAIN_TO_ADC( 400, SENSE_MOHM, 20),
  25         MA_MOHM_GAIN_TO_ADC(  30, SENSE_MOHM, 20),
  26 #ifdef PWMLED2_TESTING_WITH_350MA_LED
  27         MA_MOHM_GAIN_TO_ADC( 400, SENSE_MOHM,  1)
  28 #else
  29         MA_MOHM_GAIN_TO_ADC(2500, SENSE_MOHM,  1)
  30 #endif
  31 };
  32
  33 static uint16_t adc_vals[N_PWMLEDS*N_PWMLED_MODES] = {
  34         /* pwmled0 */
  35         MA_MOHM_GAIN_TO_ADC(  20, SENSE_MOHM, 20),
  36         MA_MOHM_GAIN_TO_ADC(  50, SENSE_MOHM, 20),
  37         MA_MOHM_GAIN_TO_ADC( 100, SENSE_MOHM, 20),
  38         MA_MOHM_GAIN_TO_ADC( 350, SENSE_MOHM, 20),
  39         /* pwmled1 */
  40         16, 32, 64, 112,
  41 #if 0
  42         MA_MOHM_GAIN_TO_ADC(   5, SENSE_MOHM, 20),
  43         MA_MOHM_GAIN_TO_ADC(  12, SENSE_MOHM, 20),
  44         MA_MOHM_GAIN_TO_ADC(  16, SENSE_MOHM, 20),
  45         MA_MOHM_GAIN_TO_ADC(  20, SENSE_MOHM, 20),
  46 #endif
  47         /* pwmled2 */
  48         24, 32, 40, 48
  49 #if 0
  50 #ifdef PWMLED2_TESTING_WITH_350MA_LED
  51         MA_MOHM_GAIN_TO_ADC( 100, SENSE_MOHM,  1),
  52         MA_MOHM_GAIN_TO_ADC( 140, SENSE_MOHM,  1),
  53         MA_MOHM_GAIN_TO_ADC( 250, SENSE_MOHM,  1),
  54         MA_MOHM_GAIN_TO_ADC( 350, SENSE_MOHM,  1),
  55 #else
  56         MA_MOHM_GAIN_TO_ADC( 150, SENSE_MOHM,  1),
  57         MA_MOHM_GAIN_TO_ADC( 350, SENSE_MOHM,  1),
  58         MA_MOHM_GAIN_TO_ADC( 700, SENSE_MOHM,  1),
  59         MA_MOHM_GAIN_TO_ADC(2400, SENSE_MOHM,  1),
  60 #endif
  61 #endif
  62 };
  63
  64 #define ST_DISABLED 0
  65 #define ST_OFF      1
  66 #define ST_PROBING  2
  67 #define ST_ON       3
  68 // The above are constructed so that the following work:
  69 #define ST_IS_ON(s)     ((s) & 0x02)
  70 #define ST_CAN_SET_MODE(s)      ((s) & 0x01)
  71
  72 void init_pwmled()
  73 {
  74         unsigned char i, j;
  75
  76         for (i = 0; i < N_PWMLEDS; i++) {
  77                 pwmled_t *led = pwmleds + i;
  78                 led->err_sum = 0;
  79                 led->target = adc_vals[i*N_PWMLED_MODES];
  80                 led->pwm = 0;
  81                 led->mode = 1;
  82                 led->state = ST_PROBING;
  83                 led->probe_steps = 0;
  84
  85                 for (j = 0; j < N_PWMLED_MODES; j++) {
  86                         led->mode_pwm[j] = 0;
  87                         led->err_sums[j] = 0;
  88                 }
  89         }
  90 }
  91
  92 void pwmled_set_mode(unsigned char n, unsigned char mode)
  93 {
  94         pwmled_t *led = pwmleds + n;
  95
  96         if (!ST_CAN_SET_MODE(led->state))
  97                 return;
  98
  99         if (led->mode) { // save the previous state
 100                 led->mode_pwm[led->mode - 1] = led->pwm;
 101                 led->err_sums[led->mode - 1] = led->err_sum;
 102         }
 103
 104         led->mode = mode;
 105
 106         if (mode > 0 && mode <= N_PWMLED_MODES) {
 107                 led->target = adc_vals[n*N_PWMLED_MODES + mode - 1];
 108                 led->state = ST_ON;
 109                 led->pwm = led->mode_pwm[mode - 1];
 110                 led->err_sum = led->err_sums[mode - 1];
 111                 pwm_set(n, led->pwm);
 112         } else {
 113                 led->state = ST_OFF;
 114                 pwm_off(n);
 115         }
 116 }
 117
 118 void pwmled_adc(unsigned char n, uint16_t adcval)
 119 {
 120         pwmled_t *led = pwmleds + n;
 121         uint16_t old_pwm;
 122         int32_t sum;
 123         unsigned char shift;
 124
 125         if (!ST_IS_ON(led->state))
 126                 return;
 127
 128         // FIXME: test for maximum adcval value (adc_max[n])
 129
 130         old_pwm = led->pwm;
 131
 132         shift = led->state == ST_PROBING ? 3 : 5;
 133
 134         sum = ((int32_t)led->pwm << shift)
 135                 + led->err_sum + led->target - adcval;
 136
 137         if (sum < 0)
 138                 sum = 0;
 139
 140         led->pwm = sum >> shift;
 141         sum -= led->pwm << shift;
 142         led->err_sum = sum;
 143
 144         if (led->state == ST_PROBING) {
 145                 if (led->pwm == old_pwm) {
 146                         if (led->probe_steps < 10)
 147                                 led->probe_steps++;
 148                 } else {
 149                         led->probe_steps = 0;
 150                 }
 151
 152                 if (led->probe_steps >= 10 || old_pwm > led->pwm) {
 153
 154                         led->mode_pwm[led->mode - 1] = led->pwm;
 155
 156                         if (led->mode < N_PWMLED_MODES) {
 157                                 led->probe_steps = 0;
 158                                 led->err_sum = 0;
 159
 160                                 led->mode++;
 161                                 led->target = adc_vals[n*N_PWMLED_MODES+led->mode-1];
 162                         } else {
 163                                 unsigned char i;
 164
 165                                 led->state = ST_OFF;
 166
 167                                 log_byte(0xF0);
 168                                 log_byte(n);
 169                                 log_word(jiffies);
 170
 171                                 for (i = 0; i < N_PWMLED_MODES; i++)
 172                                         log_word(led->mode_pwm[i]);
 173
 174                                 log_flush();
 175                         }
 176                 }
 177         }
 178
 179         if (led->pwm == old_pwm)
 180                 return;
 181
 182         if (led->pwm > (PWM_MAX << PWM_STEP_SHIFT)/2) {
 183                 pwm_off(n);
 184                 led->state = ST_DISABLED;
 185                 log_byte(0xF1);
 186                 log_byte(n);
 187                 log_word(jiffies);
 188                 log_flush();
 189         }
 190
 191         pwm_set(n, led->pwm);
 192 }
 193