On Wed, 30 Mar 2011, Cristiano Cesaretto wrote:

>>> The PIC uses the Microchip HID bootloader for the firmware upgrades.
>>>
>>> Some units stopped working and I can't figure out why. The PIC is not
>>> detected by the USB bus and doesn't display the usual startup screen on
>> the
>>> display.
>>
>> The PIC is browning out, and the bootloader code is randomly executing
>> and erasing the flash as a result.  Enable brownout reset.
>>
> Do you know how it happens?
> Could it be because when the pic is browning out, garbage goes into the
> program counter and random instruction get executed?

Yes, that's exactly what happens.  The program counter is one of the
first registers to "fail" in a brownout condition.

--
John W. Temples, III
--=20
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