#include <avr/io.h>
#include "adc_probe_ext.h"

void adc_init(void)
{
    // Vcc as reference, select ADC2 (MUX = 0b010)
    ADMUX = (0 << REFS1) | (0 << REFS0) | // VCC as reference
            (0 << ADLAR) |                // Right adjust result
            (0b010);                      // ADC2

    // Enable ADC, prescaler = 64 (assuming 8 MHz → ADC freq = 125 kHz)
    ADCSRA = (1 << ADEN) |                // Enable ADC
             (1 << ADPS2) | (1 << ADPS1); // Prescaler = 64
}

uint16_t adc_read(uint8_t channel)
{
    // Set channel (0–7), keeping the other bits in ADMUX
    ADMUX = (ADMUX & 0xF8) | (channel & 0x07);

    ADCSRA |= (1 << ADSC); // Start conversion
    while (ADCSRA & (1 << ADSC))
        ; // Wait for conversion to finish

    return ADC; // Return 10-bit result
}

uint8_t is_device_connected(void)
{
    uint16_t value = adc_read(2); // ADC2 = PA2

    // Zakładamy 5V Vcc → 2.5V = około 512
    if (value > 400 && value < 600)
    {
        return 1; // Podłączone (w granicach tolerancji)
    }

    return 0; // Odłączone (napięcie bliskie 0 lub 5V)
}