pic keypad

N

nevada

New Member

• Nov 6, 2003

• #1

Hello I need help how to interface 4x4 matrix keypad to pic16F84 using PORTB and display keypressed on PORTA or LCD. Using no external resistors only internal pull ups. Using Assembly code

Thank you will appriciate very much

I would like must as possible explanation of the code.
Have a good day.

 

N

nevada

New Member

• Nov 6, 2003

• #2

ssd

sdsddssdds

 

Exo

Active Member

• Nov 7, 2003

• #3

What kind of keypad (multiplex, 1 button , 1000 buttons???? ) and what kind of display (7-segment, LCD... )

 

C

checkmate

New Member

• Nov 7, 2003

• #4

The standard 4x4 matrix keypad configuration I know requires at least 4 external resistors and and equal number of diodes. As far as I know, there are no internal pullups, only switches. You will also have to implement either hardware or software switch debouncing. (Of course, software is much more convenient.)

 

N

nevada

New Member

• Nov 7, 2003

• #5

keypad

Thanks for replying checkmate
but PORTB in the 16fxx pic has internal weak pull up. It is enable by clearing bit 7 of OPTION_REG. if i am not correct i will welcome your input
thanks.