/********************************************************************/
/*  DIY Arduino Mega Pinball Machine                                */
/*__________________________________________________________________*/
/*                                                                  */
/*  port    bit   type              item        description         */
/*_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ */
/*                                                                  */
/*  PORTA   0     input, pullup -   bumper 0                        */
/*  PORTA   1     input, pullup -   bumper 1                        */
/*  PORTA   2     input, pullup -   bumper 2                        */
/*  PORTA   3     input, pullup -   bumper 3                        */
/*  PORTA   4     input, pullup -   bumper 4                        */
/*  PORTA   5     input, pullup -   bumper 5                        */
/*  PORTA   6     input, pullup -   bumper 6                        */
/*  PORTA   7     input, pullup -   bumper 7                        */
/*                                                                  */
/*  PORTB   0     output        -   LCD RS      register select     */
/*  PORTB   1     output        -   LCD RW      read/!write         */
/*  PORTB   2     output        -   LCD E       enable              */
/*                                                                  */
/*  PORTL   0     output        -   LCD D0      data 0              */
/*  PORTL   1     output        -   LCD D1      data 1              */
/*  PORTL   2     output        -   LCD D2      data 2              */
/*  PORTL   3     output        -   LCD D3      data 3              */
/*  PORTL   4     output        -   LCD D4      data 4              */
/*  PORTL   5     output        -   LCD D5      data 5              */
/*  PORTL   6     output        -   LCD D6      data 6              */
/*  PORTL   7     output        -   LCD D7      data 7              */
/*__________________________________________________________________*/
/*                                                                  */
/*  This code was run on an ATmega2560 processor mounted to an      */
/*  Arduino Mega 2560. The inputs were simple foil contacts, and    */
/*  the outputs were several LEDs and a 1602A LCD module.           */
/********************************************************************/

//program setup
#define F_CPU 16000000UL
#include <avr/io.h>
#include <stdio.h>
#include <string.h>
#include <util/delay.h>

//global variables
uint16_t score = 0;
char line_1[16];
char line_2[16];

//function prototypes
void instruction_LCD(unsigned char);
void data_LCD(char *);

//main function
int main(void)
{
  //port initialization
  DDRA = 0x00;  //PORTA bits 0-7 input
  PORTA = 0xFF; //PORTA bits 0-7 pullup enabled
  DDRB = 0x07;  //PORTB bits 0-2 output
  PORTB = 0x00; //PORTB bits 0-2 off
  DDRL = 0xFF;  //PORTL bits 0-7 output
  PORTL = 0x00; //PORTL bits 0-7 off
  
  //LCD setup
  instruction_LCD(0x38);        //function set: interface data bits 8, number of lines 2, font size 5x8
  instruction_LCD(0x0C);        //display on/off: entire display on, cursor off, cursor position off
  instruction_LCD(0x06);        //entry mode set: cursor move increment, display shift none
  instruction_LCD(0x01);        //clear display
  
  //LCD line 1
  strcpy(line_1, "Pinball Machine");  //set first line message
  instruction_LCD(0x80);        //move to start of first line
  data_LCD(line_1);         //print first line message
  
  //LCD line 2
  strcpy(line_2, "ECET 38001");   //set second line message
  instruction_LCD(0xC0);        //move to start of second line
  data_LCD(line_2);         //print second line message
  
  //delay 3s for splash screen
  _delay_ms(3000);          //wait 3s
  
  //LCD setup
  instruction_LCD(0x01);        //clear display
  
  //LCD line 1
  strcpy(line_1, "SCORE:");     //set first line message
  instruction_LCD(0x80);        //move to start of first line
  data_LCD(line_1);         //print first line message
  
  //loop
  while (1)
  {     
    //LCD line 2
    snprintf(line_2, 15, "%d", score);  //set char representation of score as second line message
    instruction_LCD(0xC0);        //move to start of second line
    data_LCD(line_2);         //print second line message
    
    //increment score if bumper sensor is pressed
    if ((~PINA & 0x01) || (~PINA & 0x02) || (~PINA & 0x04) || (~PINA & 0x08) || (~PINA & 0x10) || (~PINA & 0x20) || (~PINA & 0x40) || (~PINA & 0x80))
    {
      score++;    //increment score
    }
    
    //delay 50ms for button debounce system
    _delay_ms(50);    //wait 50ms
  }
}

//instruction_LCD function
void instruction_LCD(unsigned char instruction)
{
  PORTB = 0x00;         //disable, write, instruction
  PORTL = instruction;      //set instruction
  PORTB |= 0x04;          //enable
  _delay_ms(2);         //wait
  PORTB &= ~(0x04);       //disable
  _delay_ms(2);         //wait
}

//data_LCD function
void data_LCD(char *char_array_ptr)
{
  PORTB = 0x01;         //disable, write, data
  while(*char_array_ptr != '\0')  //while char at char_array_ptr is not NULL
  {
    PORTB |= 0x04;          //enable
    PORTL = *char_array_ptr;    //set data
    char_array_ptr++;       //increment char_array_ptr
    _delay_ms(2);         //wait
    PORTB &= 0x01;          //disable
    _delay_ms(2);         //wait
  }
}