diff options
Diffstat (limited to 'keyboard/atomic/atomic.c')
| -rw-r--r-- | keyboard/atomic/atomic.c | 61 | 
1 files changed, 61 insertions, 0 deletions
| diff --git a/keyboard/atomic/atomic.c b/keyboard/atomic/atomic.c index 5e31264e68..3996497161 100644 --- a/keyboard/atomic/atomic.c +++ b/keyboard/atomic/atomic.c @@ -57,3 +57,64 @@ void led_set_kb(uint8_t usb_led) {  	led_set_user(usb_led);  } + +#ifdef BACKLIGHT_ENABLE +#define CHANNEL OCR1C + +void backlight_init_ports() +{ + +    // Setup PB7 as output and output low. +    DDRB |= (1<<7); +    PORTB &= ~(1<<7); +     +    // Use full 16-bit resolution.  +    ICR1 = 0xFFFF; + +    // I could write a wall of text here to explain... but TL;DW +    // Go read the ATmega32u4 datasheet. +    // And this: http://blog.saikoled.com/post/43165849837/secret-konami-cheat-code-to-high-resolution-pwm-on +     +    // Pin PB7 = OCR1C (Timer 1, Channel C) +    // Compare Output Mode = Clear on compare match, Channel C = COM1C1=1 COM1C0=0 +    // (i.e. start high, go low when counter matches.) +    // WGM Mode 14 (Fast PWM) = WGM13=1 WGM12=1 WGM11=1 WGM10=0 +    // Clock Select = clk/1 (no prescaling) = CS12=0 CS11=0 CS10=1 +     +    TCCR1A = _BV(COM1C1) | _BV(WGM11); // = 0b00001010; +    TCCR1B = _BV(WGM13) | _BV(WGM12) | _BV(CS10); // = 0b00011001; + +    backlight_init(); +} + +void backlight_set(uint8_t level) +{ +    if ( level == 0 ) +    { +        // Turn off PWM control on PB7, revert to output low. +        TCCR1A &= ~(_BV(COM1C1)); +        CHANNEL = 0x0; +        // Prevent backlight blink on lowest level +        PORTB &= ~(_BV(PORTB7)); +    } +    else if ( level == BACKLIGHT_LEVELS ) +    { +        // Prevent backlight blink on lowest level +        PORTB &= ~(_BV(PORTB7)); +        // Turn on PWM control of PB7 +        TCCR1A |= _BV(COM1C1); +        // Set the brightness +        CHANNEL = 0xFFFF; +    } +    else         +    { +        // Prevent backlight blink on lowest level +        PORTB &= ~(_BV(PORTB7)); +        // Turn on PWM control of PB7 +        TCCR1A |= _BV(COM1C1); +        // Set the brightness +        CHANNEL = 0xFFFF >> ((BACKLIGHT_LEVELS - level) * ((BACKLIGHT_LEVELS + 1) / 2)); +    } +} + +#endif
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