I've run into a problem with a 16F886 chip that I program using the Tiny
Bootloader.  The chip is located in a noisy RF environment close to some
radio transmitter components.

It was working as expected.  The correct numbers and characters were coming
up on the graphic LCD display.  I have put new programs in it to test
various things out.  Things seemed to be going well until last evening.  I
was getting slight pause for the bootloader on turnon, as expected, before
the main program would start and I would get a chirp on a buzzer and LCD
would come on, all as expected.

Now when I switch it on, one of two things happen.  I either get no outward
appearance that anything is happening (completely dead) or the buzzer chirps
immediately without the bootloader delay and a couple of special graphic
characters are screwed up on the LCD screen.  Other parts of the display are
working and the adc output displayed is correct.

I'm wondering what has happened.  The only thing that I can think of is that
the memory has become corrupted somehow.  The bootloader is no longer
working, so it must be skipping that code and the area where the special
graphic characters were stored must be toast as well.

On startup the bootloader looks for a signal from the serial port.  Could
the bootloader have become active when nothing was attached to the port due
to some random noise that looked like a signal from the PC?  Or is this too
fair fetched?

Can memory be corrupted in PICs any other way?  Power glitches and the like?

Any suggestions?

Gordon Williams



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