diff options
| -rw-r--r-- | quantum/backlight/backlight_soft.c | 37 |
1 files changed, 30 insertions, 7 deletions
diff --git a/quantum/backlight/backlight_soft.c b/quantum/backlight/backlight_soft.c index a6aba7782c..f481dbae89 100644 --- a/quantum/backlight/backlight_soft.c +++ b/quantum/backlight/backlight_soft.c @@ -20,6 +20,7 @@ { BACKLIGHT_PIN } #endif +static uint16_t s_duty_pattern = 0; static const pin_t backlight_pins[] = BACKLIGHT_PIN_INIT; #define BACKLIGHT_LED_COUNT (sizeof(backlight_pins) / sizeof(pin_t)) @@ -46,21 +47,43 @@ void backlight_off(pin_t backlight_pin) { } void backlight_init_ports(void) { - // Setup backlight pin as output and output to on state. - FOR_EACH_LED(setPinOutput(backlight_pin); backlight_on(backlight_pin);) + // Setup backlight pin as output and output to off state. + FOR_EACH_LED(setPinOutput(backlight_pin); backlight_off(backlight_pin);) } +// clang-format off + +/** \brief PWM duty patterns + * + * We scale the current backlight level to an index within this array. This allows + * backlight_task to focus on just switching LEDs on/off, and we can predict the duty pattern + */ +static uint16_t backlight_duty_table[] = { + 0b0000000000000000, + 0b1000000000000000, + 0b1000000010000000, + 0b1000001000010000, + 0b1000100010001000, + 0b1001001001001000, + 0b1010101010101010, + 0b1110111011101110, + 0b1111111111111111, +}; +#define backlight_duty_table_size (sizeof(backlight_duty_table) / sizeof(backlight_duty_table[0])) + +// clang-format on + +static uint8_t scale_backlight(uint8_t v) { return v * (backlight_duty_table_size - 1) / BACKLIGHT_LEVELS; } + +void backlight_set(uint8_t level) { s_duty_pattern = backlight_duty_table[scale_backlight(level)]; } + void backlight_task(void) { static uint8_t backlight_tick = 0; - if ((0xFFFF >> (get_backlight_level() * ((BACKLIGHT_LEVELS + 1) / 2))) & (1 << backlight_tick)) { + if (s_duty_pattern & ((uint16_t)1 << backlight_tick)) { FOR_EACH_LED(backlight_on(backlight_pin);) } else { FOR_EACH_LED(backlight_off(backlight_pin);) } backlight_tick = (backlight_tick + 1) % 16; } - -void backlight_set(uint8_t level) { - // noop as backlight_task uses get_backlight_level() -} |