Software backlight improvements (#7255)

* Update software backlight to precalculated duty patterns

* Update default backlight state to match avr pwm

* Move function to make diff look nicer
This commit is contained in:
Joel Challis 2019-12-16 16:35:08 +00:00 committed by GitHub
commit bc2157eea8
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@ -10,7 +10,7 @@
#endif #endif
#ifndef BACKLIGHT_ON_STATE #ifndef BACKLIGHT_ON_STATE
# define BACKLIGHT_ON_STATE 0 # define BACKLIGHT_ON_STATE 1
#endif #endif
#ifdef BACKLIGHT_PINS #ifdef BACKLIGHT_PINS
@ -20,6 +20,7 @@
{ BACKLIGHT_PIN } { BACKLIGHT_PIN }
#endif #endif
static uint16_t s_duty_pattern = 0;
static const pin_t backlight_pins[] = BACKLIGHT_PIN_INIT; static const pin_t backlight_pins[] = BACKLIGHT_PIN_INIT;
#define BACKLIGHT_LED_COUNT (sizeof(backlight_pins) / sizeof(pin_t)) #define BACKLIGHT_LED_COUNT (sizeof(backlight_pins) / sizeof(pin_t))
@ -46,14 +47,38 @@ void backlight_off(pin_t backlight_pin) {
} }
void backlight_init_ports(void) { void backlight_init_ports(void) {
// Setup backlight pin as output and output to on state. // Setup backlight pin as output and output to off state.
FOR_EACH_LED(setPinOutput(backlight_pin); backlight_on(backlight_pin);) 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_task(void) { void backlight_task(void) {
static uint8_t backlight_tick = 0; 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);) FOR_EACH_LED(backlight_on(backlight_pin);)
} else { } else {
FOR_EACH_LED(backlight_off(backlight_pin);) FOR_EACH_LED(backlight_off(backlight_pin);)
@ -61,6 +86,4 @@ void backlight_task(void) {
backlight_tick = (backlight_tick + 1) % 16; backlight_tick = (backlight_tick + 1) % 16;
} }
void backlight_set(uint8_t level) { void backlight_set(uint8_t level) { s_duty_pattern = backlight_duty_table[scale_backlight(level)]; }
// noop as backlight_task uses get_backlight_level()
}