Diskuzní fórum Elektro Bastlírny

Kód: Vybrat vše

// 9.6 MHz, built in resonator
#define F_CPU 9600000
#define PWM_OUT 1 //PWM output on PB1
#define HOLD 4 // HOLD signal on PB4

#include <avr/io.h>

void adc_setup (void)
{
    // Set the ADC input to PB2/ADC1
    ADMUX |= (1 << MUX0);
    ADMUX |= (1 << ADLAR);

    // Set the prescaler to clock/128 & enable ADC
    ADCSRA |= (1 << ADPS1) | (1 << ADPS0) | (1 << ADEN);
}

int adc_read (void)
{
    // Start the conversion
    ADCSRA |= (1 << ADSC);

    // Wait for it to finish
    while (ADCSRA & (1 << ADSC));

    return ADCH;
}

void pwm_setup(void)
{
    // Set Timer 0 prescaler to clock/8.
    // At 9.6 MHz this is 1.2 MHz.
    TCCR0B |= (1 << CS01) | (1 << CS00);
    // Set to 'Fast PWM' mode
    TCCR0A |= (1 << WGM01) | (1 << WGM00);
    // Clear OC0B output on compare match, upwards counting.
    TCCR0A |= (1 << COM0B1);
}

void pwm_write (int val)
{
    OCR0B = val;
}

// ... adc_setup, adc_read, pwm_setup, pwm_write ...

int main (void)
{
    int adc_in;

    // LED is an output.
    DDRB |= (1 << PWM_OUT);
    DDRB &= ~(1<<HOLD); // Makes HOLD pin of PORTB as Input

    adc_setup();
    pwm_setup();
    while (1) {
        // Get the ADC value
        adc_in = adc_read();
        if (PINB & (1<<HOLD)) {
             // Now write it to the PWM counter
            pwm_write(adc_in);
        }
    }
}

Kód: Vybrat vše

/* 7 */ #include <avr/wdt.h>
/* 57 */ wdt_enable(WDTO_500MS);
/* 59 */  wdt_reset();

Kód: Vybrat vše

// Track and hold (sample and hold) circuit with ATtiny13A
// voltage input on pin 7 (PB2/ADC1), PWM output on pin 6 (PB1),
// control input (H=track, L=hold) on pin 3 (PB4)
// fclk 9.6 MHz, built in resonator
// original source: https://adnbr.co.uk/articles/adc-and-pwm-basics
// original source: https://gist.github.com/adnbr/9289235
// modification: http://www.ebastlirna.cz/modules.php?name=Forums&file=viewtopic&p=1175950

#define F_CPU 9600000
#define PWM_OUT 1 //PWM output on PB1
#define HOLD 4 // HOLD signal on PB4

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

void adc_setup (void)
{
    // Set the ADC input to PB2/ADC1
    ADMUX |= (1 << MUX0);
    ADMUX |= (1 << ADLAR);
    ADMUX |= (1 << REFS0); // set ADC ref. to internal ref. 1.1V

    // Set the prescaler to clock/128 & enable ADC (fclk for ADC cca 75 kHz)
    //ADCSRA |= (1 << ADPS1) | (1 << ADPS0) | (1 << ADEN);
    // Set the prescaler to clock/64 & enable ADC (fclk for ADC cca 150 kHz)
    ADCSRA |= (1 << ADPS1) | (0 << ADPS0) | (1 << ADEN);
}

int adc_read (void)
{
    // Start the conversion
    ADCSRA |= (1 << ADSC);

    // Wait for it to finish
    while (ADCSRA & (1 << ADSC));

    return ADCH;
}

void pwm_setup(void)
{
    // Set Timer 0 prescaler to fclk/n
    //TCCR0B |= (1 << CS01) | (1 << CS00);//n=64, fpwm cca 550 Hz
    //TCCR0B |= (1 << CS01) | (0 << CS00);//n=8, fpwm cca 4.464 kHz
    TCCR0B |= (0 << CS01) | (1 << CS00);//n=1=no prescaling, fpwm cca 35.71 kHz
    // Set to 'Fast PWM' mode
    TCCR0A |= (1 << WGM01) | (1 << WGM00);
    // Clear OC0B output on compare match, upwards counting.
    TCCR0A |= (1 << COM0B1);
}

void pwm_write (int val)
{
    OCR0B = val;
}

// ... adc_setup, adc_read, pwm_setup, pwm_write, watchdog ...

int main (void)
{
    int adc_in;

    // LED is an output.
    DDRB |= (1 << PWM_OUT);
    DDRB &= ~(1<<HOLD); // Makes HOLD pin of PORTB as Input

    adc_setup();
    pwm_setup();
    wdt_enable(WDTO_500MS);
    while (1) {
        // Get the ADC value
        wdt_reset();
        adc_in = adc_read();
        if (PINB & (1<<HOLD)) {
             // Now write it to the PWM counter
            pwm_write(adc_in);
        }
    }
}