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@ -232,12 +232,12 @@ ISR(TIMERx_OVF_vect) { |
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// See http://jared.geek.nz/2013/feb/linear-led-pwm |
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static uint16_t cie_lightness(uint16_t v) { |
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if (v <= (unsigned long)ICRx / 12) // If the value is less than or equal to ~8% of max |
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if (v <= (uint32_t)ICRx / 12) // If the value is less than or equal to ~8% of max |
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{ |
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return v / 9; // Same as dividing by 900% |
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} else { |
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// In the next two lines values are bit-shifted. This is to avoid loosing decimals in integer math. |
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uint32_t y = (((uint32_t)v + (unsigned long)ICRx / 6) << 5) / ((unsigned long)ICRx / 6 + ICRx); // If above 8%, add ~16% of max, and normalize with (max + ~16% max) |
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uint32_t y = (((uint32_t)v + (uint32_t)ICRx / 6) << 5) / ((uint32_t)ICRx / 6 + ICRx); // If above 8%, add ~16% of max, and normalize with (max + ~16% max) |
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uint32_t out = (y * y * y * ICRx) >> 15; // Cube it and undo the bit-shifting. (which is now three times as much due to the cubing) |
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if (out > ICRx) // Avoid overflows |
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