On Sat, 17 Jul 2004 01:01:37 +1200, Russell McMahon wrote:
> SUMMARY    Anyone have thoughts on brownout protection for low pin
> count
> processors where reset line is not available?

One solution I've used is to drive (switch) the VDD line of the PIC
with the output of your external brownout circuit if ultimate
reliability is required. Make sure all your I/O lines default to the
state you want when powered down, possibly gate any external drive
circuitry with the "power good" signal.

You know the real problem with internal brownout circuits (and the
reason I hardly ever use them any more) is that they are rarely level
programmable which means you have to run the MCU at whatever voltage
the designers set the brownout level at. Most brownout circuits also
have not been nearly as low powered as external circuits and usually
the accuracy is much poorer than external circuits.

This is one area I've hit up Microchip (and others) for improvement on
their MCUs.

Matt Pobursky
Maximum Performance Systems

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