ATTINY13 PWM

Hi, I am trying to create a PWM on Attiny13, but it fail (PB0 pin - silent). What wrong? Thx.

Code:


#define F_CPU 1200000UL

#include <avr/io.h>
#include <avr/interrupt.h>

#define PWM_PIN PB0
#define LED_PIN PB4
#define BUTTON1_PIN PB2 //+
#define BUTTON2_PIN PB3 //-

int
main(void)
{
    //TCCR0A  = ((1<<WGM00) | (1<<WGM01) | (1 << COM0A1)) ; // Fast PWM mode 3, Clear OC0A on Compare Match, set OC0A at TOP
    TCCR0A |= (1<<COM0A1);
    TCCR0A |= (1<<WGM01)|(1<<WGM00); //FAST PWM
    TCCR0B |= (0<<CS02)|(1<<CS01)|(0<<CS00); //F = F_CPU/(N * 256);   F= 1200000Hz/(8*256)= 585.94 Hz  //prescaler 8

    // i/o
    DDRB |=(1<<PWM_PIN);
    PORTB&=~(1<<PWM_PIN);

    //Led
    DDRB |=(1<<LED_PIN);
    PORTB&=~(1<<LED_PIN);

    //Buttons
    DDRB &=~(1<<BUTTON1_PIN);
    PORTB|=(1<<BUTTON1_PIN);

    DDRB &=~(1<<BUTTON2_PIN);
    PORTB|=(1<<BUTTON2_PIN);

    volatile uint8_t PWM = 0;
    OCR0A = PWM;

    while (1)
    {
        if ((PINB & (1<<BUTTON1_PIN))==0)   //ADD +
        {
            if (PWM< 254)
            {
                PWM++;
            }
            while ((PINB & (1<<BUTTON1_PIN))==0)
            {
            }
        }

        if ((PINB & (1<<BUTTON2_PIN))==0)   //SUB -
        {
            if (PWM>1)
            {
                PWM--;
            }

            while ((PINB & (1<<BUTTON2_PIN))==0)
            {
            }
        }

        if (OCR0A>9)
        {
            PORTB |=(1<<LED_PIN);
        }
        else
        {
            PORTB&=~(1<<LED_PIN);
        }

        OCR0A = PWM;
    }
}



Hi.

Looks like that is a bug affecting tiny13.
It will be solved for next release.
It should work with other tinys, for example tiny25.

Thank you for reporting.

Thanks! It work with tiny25/45/85.