Interfacing Keypad3*4 with PIC16F877A

[dashboyd]

Hello,i am saw a code to interfacing keypad with PIC16F877A like this.The keypad is interface at port d (RD1,RD2,RD3,RD4,RD5,RD6,RD7)of the microcontroller.
Can you please explain the term (if(input(pin_d6)==0) and so on in this code?Why they were using this term?This is full code for keypad interface.This code may be useful for my project also.

CODE: SELECT_ALL_CODE

void keypad34()
{
   mydata1=0;

   //detect 1st column key press
   portd=0b11011111;
   if(input(pin_d6)==0)
   {
      mydata1='1';
   }
   else if(input(pin_d1)==0)
   {
      mydata1='4';
   }
   else if(input(pin_d2)==0)
   {
      mydata1='7';
   }
   else if(input(pin_d4)==0)
   {
      mydata1='*';
   }

   //detect 2nd column key press
   portd=0b01111111;
   if(input(pin_d6)==0)
   {
      mydata1='2';
   }
   else if(input(pin_d1)==0)
   {
      mydata1='5';
   }
   else if(input(pin_d2)==0)
   {
      mydata1='8';
   }
   else if(input(pin_d4)==0)
   {
      mydata1='0';
   }

   //detect 3rd column key press
   portd=0b11110111;
   if(input(pin_d6)==0)
   {
      mydata1='3';
   }
   else if(input(pin_d1)==0)
   {
      mydata1='6';
   }
   else if(input(pin_d2)==0)
   {
      mydata1='9';
   }
   else if(input(pin_d4)==0)
   {
      mydata1='#';
   }

[ABSF]

I can understand why no one bothers to answer you cos this topic had appeared in this forum so many times.

Just do a search on the word "keypad" gave 101 matches. Do read them patiently and your answer should be there.

search.php?keywords=keypad&terms=all&author=&sc=1&sf=all&sr=posts&sk=t&sd=d&st=0&ch=300&t=0&submit=Search

Allen

[zhenning]

Hello,i am saw a code to interfacing keypad with PIC16F877A like this.The keypad is interface at port d (RD1,RD2,RD3,RD4,RD5,RD6,RD7)of the microcontroller.
Can you please explain the term (if(input(pin_d6)==0) and so on in this code?Why they were using this term?This is full code for keypad interface.This code may be useful for my project also.

CODE: SELECT_ALL_CODE

void keypad34()
{
   mydata1=0;

   //detect 1st column key press
   portd=0b11011111;
   if(input(pin_d6)==0)
   {
      mydata1='1';
   }
   else if(input(pin_d1)==0)
   {
      mydata1='4';
   }
   else if(input(pin_d2)==0)
   {
      mydata1='7';
   }
   else if(input(pin_d4)==0)
   {
      mydata1='*';
   }

   //detect 2nd column key press
   portd=0b01111111;
   if(input(pin_d6)==0)
   {
      mydata1='2';
   }
   else if(input(pin_d1)==0)
   {
      mydata1='5';
   }
   else if(input(pin_d2)==0)
   {
      mydata1='8';
   }
   else if(input(pin_d4)==0)
   {
      mydata1='0';
   }

   //detect 3rd column key press
   portd=0b11110111;
   if(input(pin_d6)==0)
   {
      mydata1='3';
   }
   else if(input(pin_d1)==0)
   {
      mydata1='6';
   }
   else if(input(pin_d2)==0)
   {
      mydata1='9';
   }
   else if(input(pin_d4)==0)
   {
      mydata1='#';
   }

the codes is checking whether the button is pressed or not. The keypad is initially pulled to vdd through resistors. any button pressed will cause the line to be pulled low =)