#include <avr/io.h>

unsigned char Hex_Data [] = {0x3F, 0x06, 0x5B, 0x4F, 0x66, 0x6D, 0x7D,
                0x07, 0x7F, 0x67, 0x77, 0x7C, 0x39, 0x5E, 0x79, 0x71};


void timer1_init() {
	TCCR1B |= (1 << WGM12); // Configure timer 1 for CTC mode
	TCCR1B |= (1 << CS11) | (1 << CS10); // Set prescaler to 64
	OCR1A = 249; // Set CTC compare value for 1ms at 16MHz with prescaler of 64
}

void my_delay_ms(unsigned int msecs) {
	while (msecs--) {
		TCNT1 = 0; // Reset timer count to 0
		TIFR1 |= (1 << OCF1A); // Clear any existing compare match flag
		while (!(TIFR1 & (1 << OCF1A))); // Wait for compare match flag to set
	}
}

void adc_init() {
    // ADC Initialization
    ADMUX |= (1 << REFS0); // AVCC with external capacitor at AREF pin
    ADCSRA |= (1 << ADEN) | (1 << ADPS1) | (1 << ADPS0); // Enable ADC and set prescaler to 8
}

unsigned int adc_read(unsigned char ch) {
	ADCSRA |= (1 << ADIF);     // Clear ADIF by writing one to it
  ADCSRA |= (1 << ADSC);     	// Start Single conversion
	while(ADCSRA & (1 << ADSC));     // Wait for conversion to complete
	return (ADC);
}

int main(void) {

	unsigned char output;
	
	DDRB &= ~0x0C;    // Set PORTB 0-1 as inputs
	PORTB |= 0x03;    // Enable pull-ups
	DDRD |= 0xFC;     // Set PORTD 2-7 as outputs
	DDRB |= 0x03;

	timer1_init(); // Initialize Timer1 for precise timing
	adc_init(); // Initialize the ADC
	
	int index = 0;

	while (1) {

		if (PINB & ~(0x08)) {
    if (PINB & 0x04) {    // Potentiometer mode
      unsigned int adc_value = adc_read(0); // Read from ADC channel 0 (A0)
      unsigned char hex_index = (adc_value) / 64; // Map ADC value (0-1023) to 0-15
      PORTD = ~(Hex_Data[hex_index] << 2);
      PORTB = ~(Hex_Data[hex_index] >> 6);
      my_delay_ms(100); // Short delay to stabilize output
        } 
		else {
			unsigned int adc_value = adc_read(0); // Read from ADC channel 0 (A0)
      unsigned char hex_index = ((adc_value) / 64); // Map ADC value (0-1023) to 0-15
			PORTD = ~(Hex_Data[index]<<2);
			PORTB = ~(Hex_Data[index]>>6);

			my_delay_ms(1505-((hex_index) * 67 + 250)); 
			index++;
			if (index >= 16)
				{(index = 0);
					}
			
			
				}	
		} else

		if (index >= 0) {
			PORTD = ~(Hex_Data[index]<<2);
			PORTB = ~(Hex_Data[index]>>6);
			my_delay_ms(1000); 
			index++;
			if (index >= 16)
				{(index = 0);
			}
		}
	}
	}