pwmled.c: mode stabilization

When changing brightness via pwmled_set_brightness() below,
we want to converge to the target value as fast as possible. Also,
we would like to somehow initialize the mode 3, which is used as
"mode 2 + other PWMLED on". So after the brightness is set,
we also set pwmleds[n].modes_not_yet_stable to MODE_STABILIZATION_TIME.
When modes_not_yet_stable is non-zero, we allow only mode 2 to be set
regardless of what is fed to pwmled_set_mode. We will then converge
to the target value of mode 2 only, and after MODE_STABILIZATION_TIME
ADC measurements, we copy the mode_pwm value to all other modes.
Only then it is allowed to set the other modes.

diff --git a/firmware/pwmled.c b/firmware/pwmled.c
index 30b10f1d307c0c501ac57fc49ff0e587b860ffdb..3d35c8785aee0bf6ac49374634baf04aac26161e 100644 (file)
--- a/firmware/pwmled.c
+++ b/firmware/pwmled.c
@@ -11,10 +11,26 @@ typedef struct {
        };
        uint16_t mode_pwm[N_PWMLED_MODES];
        int16_t err_sums[N_PWMLED_MODES];
+       unsigned char modes_not_yet_stable;
 } pwmled_t;
 
 pwmled_t pwmleds[N_PWMLEDS];
 
+/*
+ * Mode stabilization:
+ * when changing brightness via pwmled_set_brightness() below,
+ * we want to converge to the target value as fast as possible. Also,
+ * we would like to somehow initialize the mode 3, which is used as
+ * "mode 2 + other PWMLED on". So after the brightness is set,
+ * we also set pwmleds[n].modes_not_yet_stable to MODE_STABILIZATION_TIME.
+ * When modes_not_yet_stable is non-zero, we allow only mode 2 to be set
+ * regardless of what is fed to pwmled_set_mode. We will then converge
+ * to the target value of mode 2 only, and after MODE_STABILIZATION_TIME
+ * ADC measurements, we copy the mode_pwm value to all other modes.
+ * Only then it is allowed to set the other modes.
+ */
+#define MODE_STABILIZATION_TIME        (2*16)  // two seconds worth of measurements
+
 #define PWMLED2_TESTING_WITH_350MA_LED
 
 #define SENSE_MOHM     33      /* 0.033 Ohm */
@@ -119,6 +135,8 @@ void pwmled_set_mode(unsigned char n, unsigned char mode)
        led->mode = mode;
 
        if (mode > 0 && mode <= N_PWMLED_MODES) {
+               if (led->modes_not_yet_stable) // only mode 2 when !stable
+                       mode = 2;
                led->target = adc_vals[n*N_PWMLED_MODES + mode - 1];
                led->state = ST_ON;
                led->pwm = led->mode_pwm[mode - 1];
@@ -145,10 +163,14 @@ void pwmled_set_brightness(uint16_t brightness)
        CHECK_BRIGHTNESS(i, brightness & 0x7, adc_targets_0);
        adc_vals[0] = adc_targets_0[i];
        CHECK_BRIGHTNESS(i, (brightness >> 3) & 0x7, adc_targets_0);
-       adc_vals[1] = adc_targets_0[i];
+       if (adc_vals[1] != adc_targets_0[i]) {
+               adc_vals[1] = adc_targets_0[i];
+               pwmleds[0].modes_not_yet_stable = MODE_STABILIZATION_TIME;
+       }
        adc_vals[2] = adc_vals[1];
 
        CHECK_BRIGHTNESS(i, (brightness >> 6) & 0x7, adc_targets_1);
+       // we use only one mode, so no modes_not_yet_stable handling here
        adc_vals[3] = adc_targets_1[i];
        adc_vals[4] = adc_vals[3];
        adc_vals[5] = adc_vals[3];
@@ -156,7 +178,10 @@ void pwmled_set_brightness(uint16_t brightness)
        CHECK_BRIGHTNESS(i, (brightness >> 9) & 0x7, adc_targets_2);
        adc_vals[6] = adc_targets_2[i];
        CHECK_BRIGHTNESS(i, (brightness >> 12) & 0x7, adc_targets_2);
-       adc_vals[7] = adc_targets_2[i];
+       if (adc_vals[7] != adc_targets_2[i]) {
+               adc_vals[7] = adc_targets_2[i];
+               pwmleds[2].modes_not_yet_stable = MODE_STABILIZATION_TIME;
+       }
        adc_vals[8] = adc_vals[7];
 
        for (i = 0; i < N_PWMLEDS; i++) {
@@ -275,6 +300,16 @@ void pwmled_adc(unsigned char n, uint16_t adcval)
                if (pwmled_probed_ok(n, old_pwm))
                        return;
 
+       if (led->modes_not_yet_stable) {
+               if (!--led->modes_not_yet_stable) {
+                       // reached stability, copy mode 2 to mode 3 (-1)
+                       led->mode_pwm[0] = led->pwm;
+                       led->mode_pwm[2] = led->pwm;
+                       led->err_sums[0] = 0;
+                       led->err_sums[2] = 0;
+               }
+       }
+
        if (led->pwm == old_pwm)
                return;