Main.c

//-------------------------------------------
/*
Main.c
2010 - Josh Ashby
[email protected]
http://joshashby.com
http://github.com/JoshAshby
freenode - JoshAshby

Simple little program for the ATINY45 that will read the ADC on PB4 and write that value to PWM on PB0
*/
//-------------------------------------------
#include <avr/io.h>
#include <util/delay.h>
#include <avr/interrupt.h>

void pwm_setup(void);
void pwm(unsigned int value);

int main(void)
{
    pwm_setup();
    adc_start();
    for ( ; 1==1 ; )
    {
        pwm(ADCH); // read the ADCH bit, and write it to PWM
    }
    return 1;
}
void pwm_setup(void)
{
    TCCR0B |= (1<<CS00); //get everything set up for PWM
    TCCR0A |= (1<<WGM00);
    DDRB |= (1<<0);
}
void pwm(unsigned int value)
{
    TCCR0A |= (1<<COM0A1); // turn pwm on
    OCR0A = value; //set pwm to said vale
}
ISR(ADC_vect)
{
    //don't have to do anything as long as ADCH is updated
}
void adc_start(void)
{
    ADCSRA |= (1 << ADPS2)
            | (1 << ADPS1)
            | (1 << ADPS0) // Set ADC prescaler to 128 - 125KHz sample rate @ 16MHz
            | (1 << ADATE) //set auto trigger
            | (1 << ADEN)  // Enable ADC
            | (1 << ADIE)  // Enable ADC Interrupt
            | (1 << ADSC);  // Start A2D Conversions
    ADMUX |= (1 << ADLAR)
            | (1<<MUX1); // Left adjust ADC result to allow easy 8 bit reading and set the input pin as PB4
    sei();
}