AT/PS2 Keybord - PIC Interface?

[Kamikaze47]

Thanks heaps for that mytekcontrols. I really appreciate it

Now to go thru all the code and work out what its doing

I'll let u know how I go.

[mytekcontrols]

I hope it all works for you.

Here are some additional items to note:

If the code is used "as is" on a PIC18F type chip, then the following equates will probably need to be included:

TMR0IP  VAR INTCON2.2   ' TMR0 overflow interrupt priority bit
INTEDG2 VAR INTCON2.4   ' External interrupt-2 edge select bit
INT2IF  VAR INTCON3.1   ' INT2 external interrupt flag
INT2IE  VAR INTCON3.4   ' INT2 external interrupt enable
IPEN    VAR RCON.7      ' Interrupt priority enable

Also if not using priority interrupts (another 18F feature) it will be necessary to change the define from "DEFINE INTLHAND myintL" to "DEFINE INTHAND myintL", and of course some of the following parameters will need to be changed to match your situation:

    INTEDG2 = 0             ' INT2 (KBCLK) interrupt on falling edge
    INT2IP = 0              ' INT2 (KBCLK) set as low priority interrupt
    INT2IF = 0              ' INT2 (KBCLK) clear flag
    INT2IE = 1              ' INT2 (KBCLK) interrupt enabled 

    IPEN = 1                ' Enable priority levels on interrupts
    INTCON = %11000000      ' Enable all interrupts!

If you're not using an 18F series PIC, then some of the following might apply:


In the interrupt routine; there is a syntax problem. Below you will see 2 lines listed. The first is the currently used one in the interrupt routine. The second is the correct one to use on something other then an 18F series device (PIC16..., PIC17...).

    rrncf   _KBcode,F       ; shift new bits right (do this only 7 times)
;    rrf     _KBcode,F       ; use this instead for non-18F PIC's

!!! IMPORTANT !!! If you use an input other than INT2 (RB2) as your KBCLK line, be sure to change any INT2IE or INT2IF references in both the interrupt and KBmain routines to match your new assignment.


Whew!!! I think that pretty much covers it. Good Luck!

[Kamikaze47]

Ok cool. I spotted a couple of them already and changed them to suit a 16F84A, but i missed a couple. Thanks.

[mytekcontrols]

Kamikaze47,

Just out of curiousity, what are you doing that requires a full keyboard instead of something like a keypad?

Oh, and also just to let you know there are 2 keys that currently will not be decoded properly. The first is the PrntScrn/SysReq key which will put out a "*", and the other is the Pause/Break key which will mimic the NumLock key. I plan to do some more decoding for these, but simply haven't got to it yet. Any improvements you make and/or features you add, please post them here for all to see.

Thanks,
Michael

[Kamikaze47]

At the moment im going to be transmitting the decoded ascii characters over an RF link to another pic which will write them to an LCD screen. I've got the RF part working, so now just need to get the keyboard interface working.

Another project im thinking of doing with this is a device that goes inbetween your keyboard and your pc which will convert the keyboard to DVORAK. A friend of mine wants to have 2 keyboards on his PC - 1 QWERTY and 1 DVORAK, but the keyboard settings in windows are global so you cant have 2 different keyboard layouts.

Thanks for your help mytekcontrols. I'm sure this info will be usefull to a number of ppl on these forums.

[mytekcontrols]

Kamikaze47:

At the moment im going to be transmitting the decoded ascii characters over an RF link to another pic which will write them to an LCD screen. I've got the RF part working, so now just need to get the keyboard interface working.

Sounds like a very interesting project. Is this something you are doing for fun, or do you see it having commercial possiblities? If so, I hope it does well for you.

Well I put together all the pieces into one file and tested it out stand-alone. And then I pushed the compile button, while remembering that famous Clint Eastwood line "do you feel lucky?". Well I think you can guess the answer to that one. Of course there were a few errors , but nothing too terrible.

Here is what was missing:

<img src="http://www.picbasic.co.uk/forum/images/icons/icon2.gif" align="absmiddle"> from the equates:

init var bit            ' flag to use timeout test alternate return path 
ktable var word         ' translation table index

<img src="http://www.picbasic.co.uk/forum/images/icons/icon2.gif" align="absmiddle"> and from the PIC18F aliases:

INT2IP  VAR INTCON3.7   ' INT2 external interrupt priority bit

(I screwed up on this one, and accidentally cut & pasted the wroung item)

Anyway once I fixed it, everything compiled and ran just fine. Total bytes required = 2626 (wow! pretty interesting result).

Download the complete and tested file below.

[Kamikaze47]

cool. thanks.

i havnt had time to get this running yet, i will work on it over the weekend and see how i go.

yea im basically just doing it for fun. but there are a couple of projects that i have done in the past that i think would have commercial potential, but i wouldnt know how to go about doing anything about them.