AVR microcontroller scans 4X4 matrix keyboard and digital tube display program

          program name : keyboard ;
     Function description: Scan 16 keys (4X4) and display the key values ​​on the digital tube (two digits);
 
     Key points: When scanning the keys, a relatively complex two for() loop nested
     scanning scheme is used, which greatly reduces the amount of program. The loop nesting scheme made me entangled for a long time.
 The key values ​​are 0~9, up, down, left, right, confirm, and clear;
 
  Experience: Another milestone, tears are running... I seem to have become a code god...;
  Experimental time: About 14 hours (2 hours per day X7 days); 
 
 
 Completion time: 2013-11-19 23:58:22
 
*/
#include
#include

#define uint8 unsigned char //macro definition of 8-bit data type;
#define uint16 unsigned int //macro definition of 16-bit data type;

          // 0 , 1 , 2 , 3 , 4 , 5 , 6 , 
uint8 ak[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,
        // 7 , 8 , 9 , up , down , left , right ;
            0x07,0x7f,0x6f,0x62 ,0x54,0x21,0x0c};
uint8 ge=8,shi=8 ,si=0;

void bit(uint8 h) //digital tube bit selection enable function;
{
   PORTB|=0X02; //digital tube bit selection set to 1 (transparent state);
   if(h==0)
    {
PORTB&=0XFD; //clear (latch state);
}
}

void dat(uint8 u) //digital tube data enable function;   
{
   PORTB|=0X01;   
   if(u==0)
   {
     PORTB&=0XFE;
   }
}

void buzz(uint8 k) //Buzzer function;
{
   if(k==0)
    {
 PORTC&=~(0X80);
}
      else PORTC|=0X80;

}

void delay(uint8 j) //1=1000 counting cycles;
{
   uint16 h=0;
   while(j--)
    {
for(h=0;h<1000;h++);
}
}

void mega16() //Initialize each IO port;
{

  DDRA=0XFF; //PA output;
  DDRB=0XFF; //PB output;
  PORTA=0X00; //PA output all 0;
  delay(1); //Delay, 1000 counting cycles;
  bit(0); //Common cathode of digital tube all zero;
  PORTA=0X3F; //The digital tube data port loads data and displays 0;
  PORTB=1<<2; //Turn on the LED running light;
  dat(0); //Latch the digital tube data port data, eight digital tubes display 0;

  delay(30); //delay;   
  DDRD=0X0F; //PD port high four bits input, fourth bit output;
  PORTD=0XFF; //PD input port internal pull-up, output port outputs all 1;
  DDRC=0XFF; //PC port full output mode;
  PORTC=0X00; //PC port outputs all zero;
}

void led()
{
   static uint8 g=0;
   
PORTA=0Xff; //When inputting display data to the digital tube, all common cathodes must be set to 1 first,
         //otherwise the digital tube will be shadowed;
bit(0); //Eight digital tubes have common cathodes set to 1 (low level is valid);
   switch(g)
{ case 0: PORTA=ak[ge] ;dat(0);PORTA=0XFE;break;//digital tube ones;
  case 1: PORTA=ak[shi];dat(0);PORTA=0XFD;break; //digital tube tens;
  default: break; //otherwise...
}
      bit(0);
       g++;
            if(g==2)
{
  g=0;
}
}

[page]

shu(uint8 c)
{
          if(c<=2) {c++;} //1~3;
else if(c==3) {ge=10;shi=10; return 0;} //up;
     else if (c==11){ge=c ; shi=c; return 0;} //bottom;
else if(c==7) {ge=12,shi=12; return 0;} //left;
else if (c==15) {ge=13,shi=13; return 0;} //right;
else if(c==13){return 0;} //enter confirmation; ;
else if(c==14) {ge=0; shi=0; return 0;} //Clear;
else if((c>=8)&&(c<=10)){c-=1;} //7~9;
else if (c==12){ge=0;return 0;}
else { ;} //4~6;
 
 ge=c; shi=0;       
    
 
    
 

}

 key()
{    
    uint8 i=0 ,y=0,temp=0x10 ,v=0,ke=0 ,en[]={0xfe,0xfd,0xfb,0xf7};
// temp is used to detect whether a key is pressed in each row; en array is a four-column detection;             
    
for(v=0;v<4;v++) //v plus one represents a column detection;
{  
 PORTD=en[v]; //Detect four columns;
 temp=0x10;        
for(y=0;y<4;y++) //y plus one represents a key detection in a column;
{
if((PIND&temp)==0) //If a key is pressed, enter;
 {  
    for(i=0;i<250;i++){led();} //Debounce delay and scan digital tube;
if((PIND&temp)==0) //Confirm again that a key is pressed;
{
   buzz(1); //Buzzer on;
for(i=0;i<200;i++){led();} //Beeping delay;
for(i=0;i<200;i++){led();} //Beeping delay;
buzz(0); //Buzzer off;             
   
//==============Generate key value part================
if(v==1)y+=3; //Detect the second line; //
else if(v==2)y+=6; //Detect the third line; //
else if(v==3)y+=9; //Detect the fourth line; //
 else {;} //Detect the first line; //
ke=v+y; //Generate key value; //
//===========================================
shu(ke); // Send key value;
    while((PIND&temp)==0)led(); //Wait for the button to pop up;
  for(i=0;i<250;i++){led();} //Wait;
   while((PIND&temp)==0)led(); //Confirm again whether the button pops up;
  
  
  return 0; //End function;
}
                               
    
 }  
 
  temp=temp<<1; //Move left to detect the next button;
 
 }
        
           
     }
   
}

void main(void)
{
 

     mega16(); //Initialize each IO port;
buzz(1); //Buzzer on;
delay(15); //Delay 15,000 counting cycles;
buzz(0); //Buzzer off;
PORTA=0xff; //Load all 1s;
bit(0); //Latch all 1 data in the common cathode of the digital tube (digital tube off); 
delay(15); //Delay 15,000 counting cycles;
 
while(1)
 {
    led(); //Scan the digital tube;  
key(); //Scan the keyboard;
          
 
  } 
}