calculate_max_brightness_for_power_mW() [2/2]

fl::u8 calculate_max_brightness_for_power_mW	(	fl::u8	target_brightness,
		fl::u32	max_power_mW )

Determines the highest brightness level you can use and still stay under the specified power budget for all sets of LEDs.

Unlike the other internal power functions which use a pointer to a specific set of LED data, this function uses the CFastLED linked list of LED controllers and their attached data.

Parameters

target_brightness	the brightness you'd ideally like to use
max_power_mW	the max power draw desired, in milliwatts

Returns

a limited brightness value. No higher than the target brightness, but may be lower depending on the power limit.

Definition at line 880 of file power_mgt.cpp.hpp.

             {
    // gMCU_mW and every controller's dark current are baseline: present at any
    // brightness, and so kept out of the part the scalar acts on (#4156 R4).
    fl::u32 fixed_mW = gMCU_mW;
    fl::u32 controllable_mW = 0;
 
    CLEDController *pCur = CLEDController::head();
    while(pCur) {
        const fl::u32 count = pCur->size();
        // Through its RGBW conversion, and for a bound colour profile the
        // solved drives rather than the source (#4344).
        const fl::u32 unscaled_mW = controller_unscaled_power_mW(*pCur);
        const fl::u32 dark_mW = fixed_power_mW(count);
        // Dither's upward reserve does not scale with brightness, so it is
        // charged with the baseline (#4342).
        fixed_mW += dark_mW + controller_dither_reserve_mW(*pCur);
        controllable_mW += unscaled_mW > dark_mW ? unscaled_mW - dark_mW : 0;
        pCur = pCur->next();
    }
 
#if POWER_DEBUG_PRINT == 1
    Serial.print("power demand at full brightness mW = ");
    Serial.println( fixed_mW + controllable_mW);
#endif
 
    const fl::u32 requested_power_mW =
        fixed_mW + scale_power_for_brightness(controllable_mW, target_brightness);
#if POWER_DEBUG_PRINT == 1
    if( target_brightness != 255 ) {
        Serial.print("power demand at scaled brightness mW = ");
        Serial.println( requested_power_mW);
    }
    Serial.print("power limit mW = ");
    Serial.println( max_power_mW);
#endif
 
    if( requested_power_mW <= max_power_mW) {
#if POWER_LED > 0
        if( gMaxPowerIndicatorLEDPinNumber ) {
            Pin(gMaxPowerIndicatorLEDPinNumber).lo(); // turn the LED off
        }
#endif
#if POWER_DEBUG_PRINT == 1
        Serial.print("demand is under the limit");
#endif
        return target_brightness;
    }
 
    const fl::u8 recommended_brightness = brightness_within_budget(
        fixed_mW, controllable_mW, target_brightness, max_power_mW);
#if POWER_DEBUG_PRINT == 1
    Serial.print("recommended brightness # = ");
    Serial.println( recommended_brightness);
 
    fl::u32 resultant_power_mW =
        fixed_mW + scale_power_for_brightness(controllable_mW, recommended_brightness);
    Serial.print("resultant power demand mW = ");
    Serial.println( resultant_power_mW);
 
    Serial.println();
#endif
 
#if POWER_LED > 0
    if( gMaxPowerIndicatorLEDPinNumber ) {
        Pin(gMaxPowerIndicatorLEDPinNumber).hi(); // turn the LED on
    }
#endif
 
    return recommended_brightness;
}

References brightness_within_budget(), controller_dither_reserve_mW(), controller_unscaled_power_mW(), fixed_power_mW(), FL_NO_EXCEPT, gMaxPowerIndicatorLEDPinNumber, gMCU_mW, fl::CLEDController::head(), fl::CLEDController::next(), scale_power_for_brightness(), Serial, and fl::CLEDController::size().

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