/*
 * EasyStepper_v1.cpp
 *
 *     Created: 09-09-2014 15:47:49
 *      Author: Martin Axelsen @ RepRap.me
 * Environment: Atmel Studio 6.2
 *     License: CC-BY-NC-SA
 */


#define F_CPU 1000000
#include <avr/io.h>

int main(void)
{
	PORTCR = 0x00;		// Break-Before-Make disable
	PUEB = 0x00;		// Pull-up disable
	DDRB = 0x03;		// Port B0+B1+B2 as output
	PORTB = 0x00;		// Port B0+B1+B2 = low

	ADMUX = 0x02;		// Port B2 MUX ADC2
	ADCSRA = 0xe7;		// Enable ADC, auto trigger, pre-scale timing 128
	ADCSRB = 0x00;		// ADC free running mode

	int dir = 0x0;		// Direction flag
	int oldir = dir;	// Direction flag buffer
	int step;			// Step pin
	long delay0;		// Delay set point
	long delay1 = 0;	// Delay smoothened
	long delay2;		// First counter
	int adcget;			// Analog buffer

	while(1)
	{
		adcget = ADCL;

		if (adcget >= 124) {										// Catch potmeter position
			dir = 0x00;
			delay0 = 244 - adcget;
			} else {
			dir = 0x01;
			delay0 = adcget - 7;
		}

		if (adcget >= 244) {delay0 = 0;}                            // Catch >>> button
		if (adcget <= 4) {delay0 = 0;}                              // Catch <<< button

		delay0 = delay0 + 1;										// Add minimum delay to set max speed and avoid motor stalling1

		if (delay1 > delay0) {delay1--;}							// Acceleration
		if (delay1 < delay0) {delay1 = delay0;}						// Instant deccelleration

		if (oldir != dir) {											// Reset speed on direction change
			delay1 = 100;
			oldir = dir;
		}

		if ((adcget < 113) || (adcget > 135)) {						// Only run if potmeter is not at center position

			delay2 = delay1;										// Copy to buffer

			step = 0x00;
			PORTB = dir + step;										// Set pins
			while (delay2-- >0) {}									// Count down

			delay2 = delay1;										// Copy to buffer

			step = 0x02;
			PORTB = dir + step;										// Set pins
			while (delay2-- >0) {}									// Count down
		} else {
			delay1 = 100;
		}
	}
}