#include <avr/io.h>
#include <stdlib.h>
#include <util/delay.h>
#include <avr/interrupt.h>

#define max_gear 8
#define max_rpm_led 16
#define restart_RPM_delay 2
#define seven_seg PORTB 

void initializePort();
void initializeA2D();
void restartRPM(int led_cout);
void paintRPM(int local_led_count);
void paintGear();
void testHardware();
void paintAlphabet(char data);

int rpm_led_on_count = 1;
int gear = 0;
int is_pressed_up = 0;//upshift button status
int is_pressed_down = 0;//down shift button status


int main(void){
	
	initializePort();
	testHardware();
	initializeA2D();
	
	sei();//enable global interupt
	ADCSRA |= 1<<ADSC;//start a2d conversion
	
	while(1){	
		
		if(bit_is_clear(PINA,4))
		{
			//button at pin A4 is pressed
			if((gear > 0) && is_pressed_down==0 && is_pressed_up==0){
				gear--;
				is_pressed_down = 1;
				restartRPM(rpm_led_on_count);
				paintGear();
			}
				
		}else{
			//button at pin A4 is released
			is_pressed_down = 0;
		}
		

		if(bit_is_clear(PINA,5))
		{
			//button at pin A5 is pressed
			if((gear < max_gear) && is_pressed_up==0 && is_pressed_down==0){
				gear++;
				is_pressed_up = 1;
				restartRPM(rpm_led_on_count);
				paintGear();
			}
		}else{
			//button at pin A5 is released
			is_pressed_up = 0;
		}		
		_delay_ms(1);
	}

}

ISR(ADC_vect){
	uint8_t high = ADCH;
	if( high > 127){
		if(is_pressed_down == 0 && is_pressed_up == 0){
			rpm_led_on_count = ((high-127)*2)/(max_rpm_led) + 1;
			paintRPM(rpm_led_on_count);
		}
	}
	ADCSRA |= 1<<ADSC;//start next conversion
}

void initializeA2D(){
	ADCSRA |= 1<<ADPS2;//prescalar set to 16
	ADCSRA |= 1<<ADIE;//enable a2d interrupts
	ADMUX |= 1<<ADLAR;//to use 8 higher data bits in ADCH
	ADMUX |= 1<<REFS0;//to use avcc as reference
	ADCSRA |= 1<<ADEN;//enable a2d
}

void initializePort(){
	DDRA &= 0x0f;//for input
	DDRB = 0xff;//for seven segment output
	DDRC = 0xff;//for rpm led low output
	DDRD = 0xff;//for rpn led high output
	
	PORTA |= 0xf0;//make button to read 0 when pressed
	
	seven_seg = 0x00;
	PORTC = 0x00;
	PORTD = 0x00;	
}

void testHardware(){
	int clear_delay = 2;
	int display_delay = 100;
	//sevensegment display apoorv
	paintAlphabet('X');
	_delay_ms(clear_delay);
	paintAlphabet('A');
	_delay_ms(display_delay);
	paintAlphabet('X');
	_delay_ms(clear_delay);
	paintAlphabet('P');
	_delay_ms(display_delay);
	paintAlphabet('X');
	_delay_ms(clear_delay);
	paintAlphabet('O');
	_delay_ms(display_delay);
	paintAlphabet('X');
	_delay_ms(clear_delay);
	paintAlphabet('O');
	_delay_ms(display_delay);
	paintAlphabet('X');
	_delay_ms(clear_delay);
	paintAlphabet('R');
	_delay_ms(display_delay);
	paintAlphabet('X');
	_delay_ms(clear_delay);
	paintAlphabet('V');
	_delay_ms(display_delay);
	// display apporv ends
	
	restartRPM(16);
	paintGear();
	paintRPM(rpm_led_on_count);
}

/*paint seven segment display
	B0-C;
	B1-TL;
	B2-T;
	B3-TR;
	B4-BL;
	B5-B;
	B6-BR;
	B7-dot;*/
	
void paintAlphabet(char data){
	switch(data){
		case 'A': seven_seg = 0b10100000; break;
		case 'O': seven_seg = 0b10000001; break;
		case 'P': seven_seg = 0b11100000; break;
		case 'R': seven_seg = 0b01100000; break;
		case 'V': seven_seg = 0b10000101; break;
		case 'X': seven_seg = 0b11111111; break;//clear
	}

}

void paintGear(){	
	switch(gear){
		case 0 : seven_seg = 0b00000001; break;
		case 1 : seven_seg = 0b00110111; break;
		case 2 : seven_seg = 0b01000010; break;
		case 3 : seven_seg = 0b00010010; break;
		case 4 : seven_seg = 0b00110100; break;
		case 5 : seven_seg = 0b00011000; break;
		case 6 : seven_seg = 0b00001000; break;
		case 7 : seven_seg = 0b00110011; break;
		case 8 : seven_seg = 0b00000000; break;
 
	}
}

void restartRPM(int led_count){
	//decrease rpm indicator leds one by one 
	for(int i=led_count;i>=0;i--){
		paintRPM(i);
		_delay_ms(restart_RPM_delay);
	}
	
	//increase rpm indicator leds one by one 
	for(int i=1;i<=led_count;i++){
		paintRPM(i);
		_delay_ms(restart_RPM_delay);
	}
}

void paintRPM(int local_led_count){
	
	switch(local_led_count){
		case 0 :PORTD = 0x00;
				PORTC = 0x00;
				break;
		case 1 :PORTD = 0x01;
				PORTC = 0x00;
				break;
		case 2 :PORTD = 0x03;
				PORTC = 0x00;
				break;
		case 3 :PORTD = 0x07;
				PORTC = 0x00;
				break;
		case 4 :PORTD = 0x0f;
				PORTC = 0x00;
				break;
		case 5 :PORTD = 0x1f;
				PORTC = 0x00;
				break;
		case 6 :PORTD = 0x3f;
				PORTC = 0x00;
				break;
		case 7 :PORTD = 0x7f;
				PORTC = 0x00;
				break;
		case 8 :PORTD = 0xff;
				PORTC = 0x00;
				break;
		case 9 :PORTD = 0xff;
				PORTC = 0x01;
				break;
		case 10:PORTD = 0xff;
				PORTC = 0x03;
				break;
		case 11:PORTD = 0xff;
				PORTC = 0x07;
				break;
		case 12:PORTD = 0xff;
				PORTC = 0x0f;
				break;
		case 13:PORTD = 0xff;
				PORTC = 0x1f;
				break;
		case 14:PORTD = 0xff;
				PORTC = 0x3f;
				break;
		case 15:PORTD = 0xff;
				PORTC = 0x7f;
				break;
		case 16:PORTD = 0xff;
				PORTC = 0xff;
				break;		
				
	}
}