AVR MCU software button debounce and confirmation

The program process is very simple. After the system is powered on, LED0-LED3 will light up and LED4-LED7 will go out. When SW8 is pressed for the first time, LED4-LED7 will light up and LED0-LED3 will go out. When SW8 is pressed again, LED0-LED3 will light up and LED4-LED7 will go out.

There will be some jitter when the button is pressed and released, which sometimes affects the application process, so I thought of a way to use switch to judge the state of the button.

#include

#include

char B=0,choose1=1;

void SURE_key(int Key_Num); //Define key status judgment function

//=============================

void delay_ms(int k)

{

    int i,j;

    for(i=0;i

    {

       for(j=0;j<850;j++)

       ;

    }

}

//=============================

int main()

{

unsigned char i=0;

DDRA=0xff; //Initialize port A to output

PORTA=~(0xf); //Initialize port A 0-3 output low level; 4-7 output high level

DDRD=0x0; //Initialize port D to all input

PORTD|=0xff; //Turn on the pull-up resistor

   while(1)

   {   

   SURE_key(~PIND&(1<<4)); //Judge the key status, press and release B++

   if(B%2==1) PORTA=(0xf);

else PORTA=~(0xf);

}

   return 0;

}

void SURE_key(int Key_Num)

{

      switch(choose1)

     {

      case 1:

       if(Key_Num!=0) choose1=2; //Is it pressed?

  else choose1=1;

       break;  

      case 2:

       if(Key_Num!=0) choose1=3; //Is it pressed?

       else choose1=1;

       break;

      case 3:

      if(Key_Num!=0) choose1=3; //Pressed! Released?

      else choose1=4;

      break;

      case 4: //Released

       B++;

       choose1=1;

       break;

      }

}