//
// This code is modifed by Joonhaeng Lee
// joonhaenglee@gsd.harvard.edu
//
// This board read input from button and move step moter
//
// hello.stepper.bipolar.44.full.c
//
// bipolar full stepping hello-world
//
// Neil Gershenfeld
// 11/21/12
//
// (c) Massachusetts Institute of Technology 2012
// This work may be reproduced, modified, distributed,
// performed, and displayed for any purpose. Copyright is
// retained and must be preserved. The work is provided
// as is; no warranty is provided, and users accept all 
// liability.
//

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

#define output(directions,pin) (directions |= pin) // set port direction for output
#define input(direction,pin) (direction &= (~pin))
#define set(port,pin) (port |= pin) // set port pin
#define get(port,pin) ((port) & (pin)) // get port pin
#define clear(port,pin) (port &= (~pin)) // clear port pin
#define pin_test(pins,pin) (pins & pin) // test for port pin
#define bit_test(byte,bit) (byte & (1 << bit)) // test for bit set

// set up input and output pins
/*
#define serial_port PORTA
#define serial_direction DDRA
#define serial_pins PINA
#define serial_pin_in (1 << PA0)
#define serial_pin_out (1 << PA1)
*/

//

#define bridge_port PORTA // H-bridge port
#define bridge_direction DDRA // H-bridge direction
#define A2 (1 << PA0) // H-bridge output pins
#define A1 (1 << PA1) // "
#define B2 (1 << PA3) // "
#define B1 (1 << PA4) // "
#define on_delay() _delay_us(25) // PWM on time
#define off_delay() _delay_us(5) // PWM off time
#define PWM_count 100 // number of PWM cycles
#define step_count 20 // number of steps

//Button
#define button_port PORTB
#define button_pins PINB
#define button_direction DDRB
#define button_pin (1 << PB2)
#define button_interrupt (1 << PCIE1)
#define button_interrupt_pin (1 << PCINT10)

uint8_t previous_reading = 0;
uint8_t button_was_pressed = 0;
uint8_t button_pressed_length = 0;

//
// LED
#define LED_port PORTA
#define LED_direction DDRA
#define LED_pin (1 << PA7)
//
static uint8_t count;
//
//
// Set Timer
// this code from Julia's hello.ftdi.44.button-interrupt.c
// http://fab.cba.mit.edu/classes/863.17/Harvard/people/julia-ebert/assets/week-7/hello.ftdi.44.button-interrupt.c

//
ISR(TIM0_COMPA_vect) {
    //
    // Timer interrupt
    //
    if (get(button_pins, button_pin) != previous_reading) {
        if (!button_was_pressed) {
            button_was_pressed = 1;
            button_pressed_length = 0;
        } else {
            button_was_pressed = 0;
        }
        previous_reading = get(button_pins, button_pin);
    } else {
      if (button_was_pressed) // while butten is pressed
      {
         button_pressed_length ++;
      }
    }
}

//
// A+ B+ PWM pulse
//
void pulse_ApBp() {
  clear(bridge_port, A2);
  clear(bridge_port, B2);
  set(bridge_port, A1);
  set(bridge_port, B1);
   for (count = 0; count < PWM_count; ++count) {
      set(bridge_port, A1);
      set(bridge_port, B1);
      on_delay();
      clear(bridge_port, A1);
      clear(bridge_port, B1);
      off_delay();
      }
   }
//
// A+ B- PWM pulse
//
void pulse_ApBm() {
  clear(bridge_port, A2);
  clear(bridge_port, B1);
  set(bridge_port, A1);
  set(bridge_port, B2);
   for (count = 0; count < PWM_count; ++count) {
      set(bridge_port, A1);
      set(bridge_port, B2);
      on_delay();
      clear(bridge_port, A1);
      clear(bridge_port, B2);
      off_delay();
      }
   }
//
// A- B+ PWM pulse
//
void pulse_AmBp() {
  clear(bridge_port, A1);
  clear(bridge_port, B2);
  set(bridge_port, A2);
  set(bridge_port, B1);
   for (count = 0; count < PWM_count; ++count) {
      set(bridge_port, A2);
      set(bridge_port, B1);
      on_delay();
      clear(bridge_port, A2);
      clear(bridge_port, B1);
      off_delay();
      }
   }
//
// A- B- PWM pulse
//
void pulse_AmBm() {
  clear(bridge_port, A1);
  clear(bridge_port, B1);
  set(bridge_port, A2);
  set(bridge_port, B2);
   for (count = 0; count < PWM_count; ++count) {
      set(bridge_port, A2);
      set(bridge_port, B2);
      on_delay();
      clear(bridge_port, A2);
      clear(bridge_port, B2);
      off_delay();
      }
   }
//
// clockwise step
//
void step_cw() {
   pulse_ApBp();
   pulse_AmBp();
   pulse_AmBm();
   pulse_ApBm();
   }
//
// counter-clockwise step
//
void step_ccw() {
   pulse_ApBm();
   pulse_AmBm();
   pulse_AmBp();
   pulse_ApBp();
   }

int main(void) {
   //
   // main
   //
   static uint8_t i,j;
   //
   // set clock divider to /1
   //
   CLKPR = (1 << CLKPCE);
   CLKPR = (0 << CLKPS3) | (0 << CLKPS2) | (0 << CLKPS1) | (0 << CLKPS0);
   //
   // initialize output pins
   //
   /*
   set(serial_port, serial_pin_out);
   output(serial_direction, serial_pin_out);
   */
   
   //initialize LED pin
   //
   
   clear(LED_port,LED_pin);
   output(LED_direction,LED_pin);

   // Set up button
   set(button_port, button_pin);
   input(button_direction, button_pin);
   
   // initialize bridge pins
   //
   clear(bridge_port, A1);
   output(bridge_direction, A1);
   clear(bridge_port, A2);
   output(bridge_direction, A2);
   clear(bridge_port, B1);
   output(bridge_direction, B1);
   clear(bridge_port, B2);
   output(bridge_direction, B2);
   //
   //
   // Set up timer + interrupt (for button debouncing)
   TCCR0B |= ((1 << CS02) | (1 << CS00)); // Timer 0 prescaling - divides by 1024 */
   TCCR0A |= (1 << WGM01); // Put timer 0 in CTC mode
   OCR0A = 100; // Count 100 cycles for interrupt
   TIMSK0 |= (1 << OCIE0A); // enable timer compare interrupt
   sei(); // Enable global interrupts
   //
   //
   //
   // main loop
   //
   while (1) {

        // LED
        //run stepper moter


        if(!button_was_pressed){
          if( button_pressed_length > 0){
            set(LED_port,LED_pin);
            for (j = 0; j < PWM_count*0.5; ++j)
              step_ccw();
              button_pressed_length = 0;
          }
        }
        else{
          clear(LED_port,LED_pin);
        }

      
   }
   }