#include #include "backlight.h" #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 = level << OFFSET | 0x0FFF; // CHANNEL = ((1 << level) - 1); // } // else // { // // Turn on PWM control of PB7 // TCCR1A |= _BV(COM1C1); // // CHANNEL = level << OFFSET | 0x0FFF; // CHANNEL = ((1 << level) - 1); // } }