Interface AT/PS2 keyboard with pic16f877

Hi,
I am working in a project that capture the data from keyboard using pic16f877 and store then display in LCD. I connect the keyboard clock to RB0 and keyboard data to RA0 (assigned as digital I/O). Please help me to give some idea to write code . Thanks.




Please help to answer, how to handle the keyboard code,
when we press the keyboard key, it will generate make code,
when we release the keyboard key , it will generate break code.

key pressed: A.
make code: 1C.
key released : break code F0, 1C.
My question is how you read these three codes and assign the data.
need to read only make code (1C) or read both make code and break code.
Thanks.

Re: Interface keyboard with pic16f877

PicCompiler provide free c code exemples for different Pics.

Re: Interface keyboard with pic16f877

mouzid said:

PicCompiler provide free c code exemples for different Pics.

Click to expand...

There is no free pic complier code for this.

Re: Interface keyboard with pic16f877

Please help. I could not find the guide or idea in Google, Please give some idea to develop this project. thanks

Re: Interface keyboard with pic16f877

From the signal names it sounds like you want to use a PC keyboard.

It isn't as easy as it first appears, the keyboard output is not like a normal serial data stream, you have to provide the clock pulses from your PIC before the keyboard will respond.

You also have to be aware that each key produces several bytes, there is a two byte code for 'key down' and another code for 'key released', some of the special keys like the 'Windows' key may produce a long sequence of bytes, sometimes only when pressed at the same time as another key.

The keyboard also has an input port to drive the LEDs and accept some other commands. For example you have to initialize it by sending 0x55 and wait for it to respond with 0xAA (may be the other way around, I can't remember).

Do a Google search on "AT keyboard protocol", it should find something that helps.

Brian.

Re: Interface keyboard with pic16f877

https://www.electronic-engineering.ch/microchip/projects/keyboard/v1xx/keyboard_v1xx.html

Re: Interface keyboard with pic16f877

Hi,

any other guide, please help. thanks

It seems to me that before starting to work with microcontrollers, you have to learn on how to search on internet!!!

Please help. I could not find the guide or idea in Google

Click to expand...

Have you ever tried to make a simple search on google with the following words?

The first hits will give you enough informations to solve all of your problems!!!

BTW, it would be better, when asking for some help, to EXACTLY describe what are your problems and where you got stuck.

bepobalote said:

It seems to me that before starting to work with microcontrollers, you have to learn on how to search on internet!!!

Please help. I could not find the guide or idea in Google

Click to expand...

Have you ever tried to make a simple search on google with the following words?

Code:

interfacing pic pc keyboard

The first hits will give you enough informations to solve all of your problems!!!

BTW, it would be better, when asking for some help, to EXACTLY describe what are your problems and where you got stuck.

Click to expand...

Thanks for your support, you are really great, i have to donate 1000 points for this.

Added after 5 hours 21 minutes:

Just making the simple search I suggested you, in less than 3 minutes I got the following results:

http://www.electronic-engineering.ch/microchip/projects/keyboard/v1xx/keyboard_v1xx.html
http://www.computer-engineering.org/ps2keyboard/

http://homepages.tesco.net/~steve.lawther/steve/keybinfo.htm
http://www.epanorama.net/digipack/DMX_Pro/index.html#circuit

**broken link removed**
http://jpbachy.free.fr/PIC Keyboard Emulator.htm

I'm sorry but I can't do anything about your laziness...
BTW, I'm waiting for your 1000 points!!!