>
>In a message dated 15/12/97  20:52:46, you write:
>
><<
> The open-collector output pins (e.g. RA4 on 16C84) are not clamped to VDD,
> and can safely take a voltage above VDD; one of the Microchip guys quoted
> 14 volts.  >>
>As this pin doubles as the Vpp does this not force the pic into program mode
>at 13v and stop program opperation if so it would be unwise to use this pin in
>this mode of opperation unless you want to write self modifing code ???

I'll have to double check, but I'm positive that the VPP pin / program mode
pin is MCLR, not RA4.  As far as RA4 and higher voltages is concerned, a
Microchip FAE has repeatedly told me that it is OK up to about 14 Vdc.

Dwayne Reid   <dwayner@planet.eon.net>
Trinity Electronics Systems Ltd    Edmonton, Alberta, CANADA
(403) 489-3199 voice     (403) 487-6397 fax