//
// Jeffery Durand

// DC_board_buttons_v01: each button makes the motor
// go in a different direction.
// Pressing both buttons will toggle the motor speed

//
// Used parts of Neil Gershenfeld's code
//

#include <avr/io.h> // basic library
#include <util/delay.h> /* Functions to waste time */
#include <stdbool.h> // contains the booleans

// Certain functions are the same in fact but conceptually different hance the different names
// pin x is always one bit shifted x times
// DDRx manipulation
#define output(directions,pin) (directions |= pin) // set port direction for output (make 1)
#define input(directions,pin) (directions &= (~pin)) // set port direction for input, default (make 0)
// PORTx manipulation
#define set(port,pin) (port |= pin) // set port pin
#define clear(port,pin) (port &= (~pin)) // clear port pin
#define all_set(port) (port = 0xff) // set all port pins, not recommended as different names may be given to same port
#define all_clear(port) (port = 0x00) // clear all port pins
// PINx reading
#define pin_test(pins,pin) (pins & pin) // test for port pin
#define bit_test(byte,bit) (byte & (1 << bit)) // test for bit set

// PROGRAM SPECIFIC
// variables
#define on_delay() _delay_ms(1) // PWM on time
#define power_levels 15 // different levels of power


// COMPONENTS
// H-bridge output
#define bridge_port PORTA // H-bridge port
#define bridge_direction DDRA // H-bridge direction
#define IN1 (1 << PA3) // IN1
#define IN2 (1 << PA2) // IN2

// button input
#define button_port PORTB
#define button_direction DDRB
#define button_pins PINB
#define button1 (1 << PB0)
#define button2 (1 << PB1)



int main(void) {
   
   static bool both_pressed = false; // both buttons just got pressed? 
   static uint8_t delay = 0; // delay where the motor is inactive
   static uint8_t count_delay = 0; // variable for loop iteration
   static uint8_t count_power = 0; // the current power level selected (0 is highest, power_levels is lowest)
   
   //
   // set clock divider to /1
   //
   CLKPR = (1 << CLKPCE);
   CLKPR = (0 << CLKPS3) | (0 << CLKPS2) | (0 << CLKPS1) | (0 << CLKPS0);
   
   //
   // initialize H-bridge pins
   //
   clear(bridge_port, IN1);
   output(bridge_direction, IN1);
   clear(bridge_port, IN2);
   output(bridge_direction, IN2);
   
   //
   // initialize button pins
   //
   set(button_port, button1); // want pull up resistors for the buttons
   input(button_direction, button1);
   set(button_port, button2);
   input(button_direction, button2);

   //
   // main loop
   //
   while (1) {

      // button 1 only pressed: turn forward!
      if (pin_test (button_pins, button1) == 0 && pin_test (button_pins, button2) != 0){
         
         both_pressed = false; // both buttons not pressed (in case just released one button)
         clear(bridge_port, IN1); // set direction 

         // make go forward
         set(bridge_port, IN2);
         on_delay();
         // pause
         clear(bridge_port, IN2);
         for (count_delay = 0; count_delay < delay; count_delay++)
         {
            on_delay();
         }
      }

      // button 2 only pressed: turn reverse
      if (pin_test (button_pins, button1) != 0 && pin_test (button_pins, button2) == 0){
         
         both_pressed = false; // both buttons not pressed (in case just released one button)
         clear(bridge_port, IN2); // set direction

         // make go backwards
         set(bridge_port, IN1);
         on_delay();
         // pause
         clear(bridge_port, IN1);
         for (count_delay = 0; count_delay < delay; count_delay++)
         {
            on_delay();
         }
      }

      // both buttons pressed
      if (pin_test (button_pins, button1) == 0 && pin_test (button_pins, button2) == 0){
         
         // turn motor off
         clear(bridge_port, IN1);
         clear(bridge_port, IN2);

         if (both_pressed == false){
            // change delay (speed of motor)
            count_power = (count_power + 1) % power_levels;
            delay = count_power;
            // both_pressed is true (so the variable only changes once)
            both_pressed = true;
         }
      }

      // no buttons pressed
      if (pin_test (button_pins, button1) != 0 && pin_test (button_pins, button2) != 0){
         // stop running
         clear(bridge_port, IN1);
         clear(bridge_port, IN2);
         // both_pressed back to false
         both_pressed = false;
      } 

   }
   return 0;
}