Hello all.

A display I made for my wife's pharmacy uses an 18f2550 to control everythi=
ng.
When I installed it, everything was fine, but, for some reason, after a cou=
ple
of days the display stopped working. I could repeat this 'reliably' at home=
:
switching the display on/off a number of times caused a 'memory loss': bloc=
ks
of memory were erased (seemingly 32 byte-blocks). The position of the erase=
d
blocks seems random.

Now, the program itself frequently _moves_ 32-byte blocks from program memo=
ry
to RAM, but never writes in program memory. Not sure if this could be relat=
ed.

Is this device so sensitive to power outages?

I considered/tried the following:

1) I normally use an USB bootloader to load the actual software. One time a
block from the USB loader itself was erased, so I enable WRB (boot write
protect). That seemed to protect the loader.

2) Code protection was already enabled, but I reasoned that I could not
enable the program memory write protection, as the bootloader would then no=
t
be able to write new versions.

3) Finally I removed the bootloader, and put in a recompiled version, with
all protections enabled. That seems to have solved it. Many tests at home,
and now on site, and still no problems.

Q: Is there no way to retain the actual bootloader and still have some=20
protection for those spurious writes?=20

John
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