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