>      We would like to build a board based on the PIC controller
>for educational purposes, using a keypad and display, with
>communication to a PC to download programs. Do you know any
>"operating system" to control a system like this? (In Portuguese
>we say something like a "monitor" system).
Unfortunately the PICs (to the best of my knowledge) are not capable of writing
 to their program
memory.
(If there are any newer exceptions to this, someone please let me know.)
This gives you 2 choices:
1) Use a toggle switch to go between "Load" and "Run"  Look at
 http://www.dontronics.com at the
SimmStick stuff and you'll see a good example.
2) Use 2 micros where one is the "main" micro and the other one is for
 communications with the PC,
programming the chip, etc.

Best of luck,

Alan G. Smith


+---------------------------------------------------------
| Alan G. Smith
| ags@poboxes.com
| http://www.innovatus.com/ags