diff options
Diffstat (limited to 'quantum/backlight/backlight_avr.c')
| -rw-r--r-- | quantum/backlight/backlight_avr.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/quantum/backlight/backlight_avr.c b/quantum/backlight/backlight_avr.c index b3e882ffe1..4d66da80ba 100644 --- a/quantum/backlight/backlight_avr.c +++ b/quantum/backlight/backlight_avr.c @@ -3,6 +3,11 @@ #include "backlight_driver_common.h" #include "debug.h" +// Maximum duty cycle limit +#ifndef BACKLIGHT_LIMIT_VAL +# define BACKLIGHT_LIMIT_VAL 255 +#endif + // This logic is a bit complex, we support 3 setups: // // 1. Hardware PWM when backlight is wired to a PWM pin. @@ -240,6 +245,9 @@ static uint16_t cie_lightness(uint16_t v) { } } +// rescale the supplied backlight value to be in terms of the value limit +static uint32_t rescale_limit_val(uint32_t val) { return (val * (BACKLIGHT_LIMIT_VAL + 1)) / 256; } + // range for val is [0..TIMER_TOP]. PWM pin is high while the timer count is below val. static inline void set_pwm(uint16_t val) { OCRxx = val; } @@ -269,7 +277,7 @@ void backlight_set(uint8_t level) { #endif } // Set the brightness - set_pwm(cie_lightness(TIMER_TOP * (uint32_t)level / BACKLIGHT_LEVELS)); + set_pwm(cie_lightness(rescale_limit_val(TIMER_TOP * (uint32_t)level / BACKLIGHT_LEVELS))); } void backlight_task(void) {} @@ -375,7 +383,7 @@ ISR(TIMERx_OVF_vect) breathing_interrupt_disable(); } - set_pwm(cie_lightness(scale_backlight((uint16_t)pgm_read_byte(&breathing_table[index]) * 0x0101U))); + set_pwm(cie_lightness(rescale_limit_val(scale_backlight((uint16_t)pgm_read_byte(&breathing_table[index]) * 0x0101U)))); } #endif // BACKLIGHT_BREATHING |