on 17/1/02 2:50 AM, Ted Mawson at Ted.Mawson@PORTFOLIOPM.COM wrote:

> I just ordered some PIC16C771JWs to experiment with.  Can someone give
> me a reference to how to avoid this OSCAL problem / capture the data and
> write it back when I want to erase and reuse these PICs?  The
> www.microchips.com website returns zilch on a search for 'OSCAL'.

Ted,

As far as I know, the OSCCAL (two Cs) is unique to the 12C, 12CE and 16C505
series chips - ie; the ones that have the internal oscillator. This value is
written in to the last register in the factory, and the first instruction is
to move this value into the W register. To use this value, your first
instruction (for these parts) simply needs to be 'OSCCAL' - it is used to
calibrate the Oscillator.

I could be wrong, but I not think you have anything to worry about with
16C711JW parts as these do not have the internal oscillator and I am not
aware of any other pre-programmed registers that can be erased with the UV.

It will be interesting to see how Microchip will address this issue on the
forthcoming 12F series.

Regards,

Sean

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