On Mon, 30 Mar 1998 08:54:27 +0300 Peter Cousens writes: >Does anyone know the max voltage you can run a 16c84 at ? > >I tried the other day, at about 8 volts it became unstable >could this have been because it was misreading the eeprom ? >I should try programming it at a higher voltage. >But before I do, has anyone else done this ? The Absolute Maximum Rating is 7V. I suspect that the EEPROMS, both data and program, will be mis-biased at voltages higher than that and the chip will not function. Also, even if the PIC doesn't burn out right away, the high stress from excess voltage could cause it to fail very quickly. >It would be great if its possible to run direct from a 9 volt >battery It is better to drop the voltage down to about 3V, the PIC will use less current and battery life will be extended. A battery consisting of 3 or 4 AA or AAA cells in series could be connected to the PIC directly and run it for much longer than a 9V would. >>I am not bothered if the odd one gets fried in this application >also as current drain will be very low I can use a large current >limiting resistor of 330 Ohms or so in the supply line A simple regulator of a voltage divider with fairly large resistors setting the voltage to the base of an NPN transistor voltage follower could work. Of course there are reasonably-priced micropower 3-terminal linear regulators which would be ideal for longest battery life if that is important. >As a last resort suppose I could put a led in the supply line Yes, this is practical. Depending on the color of the LED about 1.5 to 3V will be dropped. And the power lost by the LED isn't completely wasted (as it would be with a linear regulator) since it could act as a pilot light. _____________________________________________________________________ You don't need to buy Internet access to use free Internet e-mail. Get completely free e-mail from Juno at http://www.juno.com Or call Juno at (800) 654-JUNO [654-5866]