qmk_firmware/drivers/backlight/backlight_software.c

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#include "backlight.h"
#include "backlight_driver_common.h"
2023-07-08 15:13:10 +02:00
#include "util.h"
#ifdef BACKLIGHT_BREATHING
# error "Backlight breathing is not available for software PWM. Please disable."
#endif
static uint16_t s_duty_pattern = 0;
// 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 const uint16_t backlight_duty_table[] = {
0b0000000000000000,
0b1000000000000000,
0b1000000010000000,
0b1000001000010000,
0b1000100010001000,
0b1001001001001000,
0b1010101010101010,
0b1110111011101110,
0b1111111111111111,
};
#define backlight_duty_table_size ARRAY_SIZE(backlight_duty_table)
// clang-format on
static uint8_t scale_backlight(uint8_t v) {
return v * (backlight_duty_table_size - 1) / BACKLIGHT_LEVELS;
}
void backlight_init_ports(void) {
backlight_pins_init();
}
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 (s_duty_pattern & ((uint16_t)1 << backlight_tick)) {
backlight_pins_on();
} else {
backlight_pins_off();
}
backlight_tick = (backlight_tick + 1) % 16;
}