What you are describing sounds an awful lot like a mouse or trackball.  Is
there some reason that you are not using a miniature trackball ???

If you want to "replace" the keyboard with your PIC based device, you could
have it emulate a keyboard (send out scan codes when the big button is
pushed) and just plug it into the keyboard port on your PC.  If there is a
requirement for limited eye movement, I would consider simply mounting a
small LCD display on the edge of the monitor with velcro.  The advantage of
this approach is that the pseudo keyboard device would work with almost any
PC or PC application...

Bob Segrest

At 09:11 AM 2/12/97 -0500, you wrote:
>> However, I need to write a PC utility which needs to read the PC's serial
>> port and display the received character on a small window on the PC
>(always
>
>Well, delphi seems like a good place to start except that your not going to
>have the low-level access to actually place the character in the keyboard
>buffer unless you write a DLL and/or .ASM driver.  However, a quick/dirty
>way of doing this might be to use 2 serial ports, and spit the character
>bakc out of the PC (using .com drivers built into Delphi) and into the PC's
>now empty Keyboard port (Just a serial port in itself).  But I think you
>should be able to use it as it is and spit the character back at the PIC's
>serial port, then have the PIC bit-bang it into the PC's Keyboard port.
>Protocol for the PC's keyboard port may not even have to be learned if you
>get the right adapter--- (RS232 ---> keyboard, IO ---> keyboard, etc....)
>
>