按65微秒稳定阈值映射混合光亮度

project/example/ble/ble_peripheral/app/src/light_transition.c

@@ -8,6 +8,7 @@ volatile uint8_t Light_Transition_FadeActive;
 #define OUTPUT_SMOOTH_SHIFT 4U
 #define LIGHT_OUTPUT_SCALE 1000U
 #define BREATH_MIN_OUTPUT (LIGHT_OUTPUT_SCALE / 100U)
+#define DUAL_MIN_STABLE_CHANNEL_OUTPUT 145U
 #define POWER_FADE_Q12_MAX 4096U
 #define POWER_FADE_ON_TICKS 140U
 #define POWER_FADE_OFF_TICKS 160U
@@ -34,6 +35,25 @@ static const uint16_t brightness_gamma_q12[100] = {
     3457U, 3525U, 3595U, 3664U, 3735U, 3806U, 3878U, 3950U, 4023U, 4096U
 };
 
+/*
+ * Mixed-light Gamma table. Its first level equals the original 50% APP level
+ * (1184/4096), where a 50:50 mix measures about 65 us per direction at 2 kHz.
+ * The remaining range is expanded to 100%, so all brightness levels remain
+ * distinct instead of clamping the lower levels to one fixed output.
+ */
+static const uint16_t mixed_brightness_gamma_q12[100] = {
+    1184U, 1185U, 1187U, 1189U, 1193U, 1198U, 1203U, 1208U, 1216U, 1223U,
+    1231U, 1240U, 1249U, 1259U, 1270U, 1282U, 1293U, 1306U, 1319U, 1333U,
+    1348U, 1363U, 1378U, 1394U, 1411U, 1428U, 1446U, 1465U, 1484U, 1504U,
+    1524U, 1544U, 1565U, 1587U, 1609U, 1632U, 1655U, 1680U, 1703U, 1728U,
+    1753U, 1780U, 1806U, 1833U, 1860U, 1888U, 1916U, 1946U, 1975U, 2005U,
+    2036U, 2067U, 2097U, 2130U, 2162U, 2195U, 2228U, 2262U, 2296U, 2331U,
+    2366U, 2402U, 2438U, 2474U, 2512U, 2549U, 2587U, 2626U, 2665U, 2704U,
+    2744U, 2785U, 2826U, 2867U, 2908U, 2951U, 2993U, 3036U, 3080U, 3124U,
+    3168U, 3213U, 3259U, 3304U, 3351U, 3397U, 3444U, 3492U, 3539U, 3588U,
+    3637U, 3686U, 3736U, 3786U, 3837U, 3888U, 3939U, 3991U, 4044U, 4096U
+};
+
 /*
  * Gamma 1.8 envelope for power-on/off. The transition progress is advanced
  * independently of the requested brightness, so every turn-on takes about
@@ -68,6 +88,18 @@ static uint16_t brightness_scale_for_level(uint8_t level)
     return brightness_gamma_q12[level - 1U];
 }
 
+static uint16_t output_brightness_scale_for_level(uint8_t level)
+{
+    if(level == 0U) return 0U;
+    if(level < BRIGHTNESS_MIN_PERCENT) level = BRIGHTNESS_MIN_PERCENT;
+    if(level > BRIGHTNESS_MAX_PERCENT) level = BRIGHTNESS_MAX_PERCENT;
+
+    if(W_PWM != 0U && C_PWM != 0U)
+        return mixed_brightness_gamma_q12[level - 1U];
+
+    return brightness_scale_for_level(level);
+}
+
 static uint16_t approach_brightness_scale(uint16_t current, uint16_t target)
 {
     uint16_t delta;
@@ -178,7 +210,7 @@ static void update_power_fade(uint8_t powered_on)
 
 void Light_Transition_SyncBrightness(uint8_t level)
 {
-    current_brightness_q12 = brightness_scale_for_level(level);
+    current_brightness_q12 = output_brightness_scale_for_level(level);
     power_fade_progress_q12 =
         level == 0U ? 0U : POWER_FADE_Q12_MAX;
     power_fade_remainder = 0U;
@@ -194,13 +226,17 @@ void Light_Transition_Task(void)
     uint16_t target_brightness_scale;
     uint16_t brightness_scale;
     uint16_t fade_scale;
+    uint16_t mix_total;
+    uint16_t weak_mix;
+    uint16_t required_total;
+    uint16_t floor_w;
     uint8_t power_transitioning;
 
     /*
      * Keep APP brightness tracking while off. Power fading is a separate
      * envelope, so on/off duration does not change with the saved brightness.
      */
-    target_brightness_scale = brightness_scale_for_level(Brightness);
+    target_brightness_scale = output_brightness_scale_for_level(Brightness);
     current_brightness_q12 =
         approach_brightness_scale(current_brightness_q12,
                                   target_brightness_scale);
@@ -218,6 +254,40 @@ void Light_Transition_Task(void)
         (uint16_t)(((uint32_t)C_PWM * brightness_scale *
                     (LIGHT_OUTPUT_SCALE / 100U) + 2048U) >> 12);
 
+    /*
+     * Keep the weaker mixed-light direction at the measured stable threshold.
+     * Raise the combined output only when the requested W:C ratio needs it.
+     * A ratio that cannot provide 145/1000 to its weak side even at full
+     * brightness is treated as single color.
+     */
+    if(W_PWM != 0U && C_PWM != 0U)
+    {
+        mix_total = (uint16_t)(W_PWM + C_PWM);
+        weak_mix = (W_PWM < C_PWM) ? W_PWM : C_PWM;
+        required_total = (uint16_t)(
+            ((uint32_t)DUAL_MIN_STABLE_CHANNEL_OUTPUT * mix_total +
+             weak_mix - 1U) / weak_mix);
+
+        if(required_total > LIGHT_OUTPUT_SCALE)
+        {
+            if(W_PWM < C_PWM)
+                target_w = 0U;
+            else
+                target_c = 0U;
+        }
+        else if((uint16_t)(target_w + target_c) < required_total)
+        {
+            floor_w = (uint16_t)(
+                ((uint32_t)required_total * W_PWM +
+                 (mix_total / 2U)) / mix_total);
+            if(floor_w == 0U) floor_w = 1U;
+            if(floor_w >= required_total)
+                floor_w = required_total - 1U;
+            target_w = floor_w;
+            target_c = required_total - floor_w;
+        }
+    }
+
     target_w = (uint16_t)(((uint32_t)target_w * fade_scale + 2048U) >> 12);
     target_c = (uint16_t)(((uint32_t)target_c * fade_scale + 2048U) >> 12);