// x_your_lab2.c 
// Name 
// Date 

//  HARDWARE SETUP:
//
//  PORT C physical connections 
//                       PORTC:  7 6 5 4 3 2 1 0
//             pwn_en_m        --| | | | | | | |--unsued     
//             digit select MSB----| | | | | |----unsued    
//             digit select    ------| | | |------unused 
//             digit select LSB--------| |--------unsued    

//hint: swizzle the pins to make the implementation less awkward

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

#define TRUE 1
#define FALSE 0
#define LOOP_DELAY 500  //delay in ms for the loop


//******************************************************************************
//                            chk_buttons                                      
//Checks the state of the button number passed to it. It shifts in ones till   
//the button is pushed. Function returns a 1 only once per debounced button    
//push so a debounce and toggle function can be implemented at the same time.  
//Adapted to check all buttons from Ganssel's "Guide to Debouncing"            
//Expects active low pushbuttons on PORTA.  Debounce time is determined by 
//external loop delay times 12. The argument "button" is the pushbutton on     
//the board S1 (button = 0) through S8 (button = 7)                    
//
uint8_t chk_buttons(uint8_t button) {
} //chk_buttons
//******************************************************************************

//***********************************************************************************
//                                   segment_sum                                    
//This function takes a 16-bit binary input value and places the appropriate 
//equivalent 4 digit BCD segment code in an array for display.                       
//The array is loaded at the exit as:  |d3|d2|colon|d1|d0|
void segsum(uint16_t sum) {
}//segment_sum
//***********************************************************************************


//***********************************************************************************
int main()
{

//configure all PORT A pins as WIREDANDPULL OPC[2:0]=111
//can only pull down, pullup is always on

//Set port A as an output. The input value will always
//be available regardless. TODO Check this.
PORTA.DIR = 0xFF;

//main while loop 
while(1){
  _delay_loop_2(LOOP_DELAY); //loop debounce required
  
  //check each button and increment the change amount
  //enable tristate buffer for pushbutton switches
  
  //assert Y7 output from decoder to allow switches to be read 

  //check each button and increment as necessary
  //bound the count

  //break up the disp_value to 4 parts, put BCD digits in an array
  segsum(disp_value);
    
  //Turn on each digit by incrementing the count to PORTC bits 4-6.
  //This will turn on digits 0 to 3 in succession.
  //PORTB bit 7 is held low constantly for this lab.
  } //while
}  //main