/* ******************************************************** */
/* Example 10.1. Timer counter 1 as a PWM generator */
/* Modulates MiniMEXLE yellow LED, SW1 and SW2 changes duty */
/* SW3 and 4 control the red LED */
/* Warning: The values are NOT CORRECT, they should be re- */
/* placed by students themselves!!! */
/* ******************************************************** */
#include <avr\io.h>
#define SW1 0
#define SW2 1
#define SW3 2
#define SW4 3
#define RedLED 5
int main(void) {
/* *********************** Init device MiniMEXLE ******************************** */
DDRB = 0b00000000; // PORTB: PWM - PB1, PB2 (LED) is output, PB6, 7 IN!!!
PORTB = 0b00000000; // LED Active low, LED off, No pull-ups
DDRC = 0b00000000; // PORTC LED on PC5 is output, SW1-4 are inputs
PORTC = 0b0000000; // LED Active high, LED off, pull-ups ON
/* *********************** Init T1 as a PWM generator *************************** */
TCCR1A = 0b00000000; // Mode: PWM, Phase Correct, 9-bit
TCCR1B = 0b00000000; // Prescaler 1:1024
OCR1A = 000; // Initialization values
OCR1B = 000; // for 1:1 duty cycle
TCNT1 = 0;
for (;;) {
if( bit_is_clear(PINC, SW1)) { // Switch 1
OCR1A += 32; // Increment OCR
OCR1B += 32;
loop_until_bit_is_set(PINC, SW1);
}
if(bit_is_clear(PINC, SW2)){ // Switch 2
OCR1A -= 32; // Decrement OCR
OCR1B -= 32;
loop_until_bit_is_set(PINC, SW2);
}
if(bit_is_clear(PINC, SW3)){ // Switch 3
PORTC |= (1<<RedLED); // Red LED ON
loop_until_bit_is_set(PINC, SW3);
}
if(bit_is_clear(PINC, SW4)) { // Switch 4
PORTC &= ~(1<<RedLED); // Red LED OFF
loop_until_bit_is_set(PINC, SW4);
}
}
}