Yes, there are EEPROM writes.  I added the external serial EEPROM so=20
that I would have space to do it in triplicate and RAID it.

Cheers,
-Neil.



On 10/27/2014 1:30 AM, Bob Blick wrote:
> Hi Neil,
>
> One of the ways people do to try to break code protection on PICs is
> quickly glitch the power supply. It can make the program counter change
> without the chip resetting. So I bet you have an EEPROM write in your
> code somewhere, and since you have no bulk capacitance you can get quick
> glitches in the power supply, and then the program counter changes to
> your EEPROM write routine. But since all that changed was the program
> counter, who knows where or what gets put into it.
>
> Also you might consider doing all on-the-fly writes to EEPROM in
> triplicate, and doing majority rule on reads from those locations. That
> way if the chip resets when writing, at worst you have is old data. But
> you still need to add some capacitors to your power supply.
>
> Best regards, Bob
>
>
> On Sun, Oct 26, 2014, at 05:17 PM, Neil wrote:
>> Hi all,
>>
>> Have a product working very well for a long time on the bench, but in a
>> truck I'm getting EEPROM data corruption.  Only real difference is the
>> power source.  Is this possible?  I switched to an external EEPROM and
>> haven't tested on the truck yet, but thought I'd ask in the mean while.
>>
>> My power supply is fairly basic --  reverse protection diode, small
>> resistor, 8V regulator, then 5V regulator.  0.1uf caps on the input and
>> output of the regulators.  Total current draw is 60mA.
>>
>> Cheers,
>> -Neil

--=20
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