help.. source code for a 4x3 alphanumeric keypad using pic16f873

[viclyndon]

pls help..

im in need of a source code (firmware)  for a  4x3 alphanumeric keypad using pic16f873 using assembly language.  The 7 pins of the keypad are connected to PORTB.    I need to know how to program this case...  1 press = a , 2 press = b, 3 press = c....etc.             

thank you

[rod_vdb]

There is plenty of source code on piclist.org try

http://www.piclist.org/techref/microchip/keymatrix.htm

Rod

[Rob]

Welcome to the boards, both of you!

[viclyndon]

How can i program the PIC so that special keys like 'ENTER' and 'DELETE' can be outputted?

[rod_vdb]

Er, that totally depends on how you are outputting your information....

If you are outputting ASCII, say out of the UART then just look up the ASCII code for caridge return, google should help you...

If you are not outputting ASCII then let us know and we can try and help

Rod

[viclyndon]

i would like to interface my 4x3 alphanumeric keypad to the PS/2..... is it difficult or not?  i mean the software and the firmware..  and what port should i best put my keypad, PORTB(using interrupts) or PORTC?

[rod_vdb]

Have a look here for information on the ps/2 protocol. You may be able to get the UART to generate these signals in its syncronous mode but I am not sure, otherwise you will have to write a software port but it does not look too dificult.

You might as well hook the keys up to PORTB if they have interrupt on change feature, it makes your job a little easier

Rod

[justDIY]

you might want to give this link a read too:

http://www.computer-engineering.org/ps2protocol/

it has a lot of information on the protocol as well as some insight to replicating the protocol with a microcontroller (timing, schematics, etc)

I have seen a lot of projects about interfacing a matrix keypad to the rs232 serial port and parallel port, but interfacing it with the ps2 port is a new one.

may I ask your application?  there maybe easier ways!

[viclyndon]

"you might want to give this link a read too:

http://www.computer-engineering.org/ps2protocol/

it has a lot of information on the protocol as well as some insight to replicating the protocol with a microcontroller (timing, schematics, etc)

I have seen a lot of projects about interfacing a matrix keypad to the rs232 serial port and parallel port, but interfacing it with the ps2 port is a new one.

may I ask your application?  there maybe easier ways! "





It's just plain interfacing the 4x3 alphanumeric keypad to the PS/2.  But if necessary im not going to make a keypad driver to make it a lot easier.  I'll just use the existing keyboard driver in the PS/2 and then work from there to my keypad to make it compatible.  Is it possible?
 

[david]

i would like to interface my 4x3 alphanumeric keypad to the PS/2..... is it difficult or not?  i mean the software and the firmware..  and what port should i best put my keypad, PORTB(using interrupts) or PORTC?

what have you put together ? have you done anything ? if you post your work we could help..

David