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tmk_keyboard/keyboard/gnapkin/backlight.c
2018-03-16 18:01:12 -10:00

54 lines
1.3 KiB
C

// http://blog.saikoled.com/post/43165849837/secret-konami-cheat-code-to-high-resolution-pwm-on
#include <avr/io.h>
#include "backlight.h"
#define FET OCR1A
uint8_t led_counter = 0;
uint8_t led_level = 0;
void backlight_init_ports()
{
DDRB |= (1<<5);
PORTB &= ~(1<<5);
TCCR1A = _BV(COM1A1) | _BV(WGM11); // = 0b10000010;
TCCR1B = _BV(WGM13) | _BV(WGM12) | _BV(CS10); // = 0b00011001;
ICR1 = 0xFFFF;
FET = 0x0000;
backlight_init();
}
void backlight_set(uint8_t level)
{
if ( level == 0 )
{
// Turn off PWM control on PB5, revert to output low.
TCCR1A &= ~(_BV(COM1A1));
FET = 0x0000;
// Prevent backlight blink on lowest level
PORTB &= ~(_BV(PORTB5));
}
else if ( level == BACKLIGHT_LEVELS )
{
// Prevent backlight blink on lowest level
PORTB &= ~(_BV(PORTB5));
// Turn on PWM control of PB5
TCCR1A |= _BV(COM1A1);
// Set the brightness
FET = 0xFFFF;
}
else
{
// Prevent backlight blink on lowest level
PORTB &= ~(_BV(PORTB5));
// Turn on PWM control of PB5
TCCR1A |= _BV(COM1A1);
// Set the brightness
FET = 0xFFFF >> ((BACKLIGHT_LEVELS - level) * ((BACKLIGHT_LEVELS + 1) / 2));
}
}