Lpc2000

Update:

The other day I reported it seemed my LPC2138 was hanging with the
clock stopped and the internal watchdog not working.

Turns out the processor was running so the watchdog was being stroked
hence not firing.

What was happening were I/O lines were changing state after an ESD hit.
In my case this turned off most of my board making it look dead.

Only some I/O lines were flipping, so it's not an easy state to detect.

I've seen this before, I guess it means I need to keep internal copies
of the ports and periodically refresh them. Of course this will only
work for logic that can handle a pin toggling as long as it returns to
the correct state. Something edge triggered would hate this.

Anyhow we solved the ESD problem by metallizing the plastic lid
enclosing the board.

We took 180 consecturive hits at 25kv without crash or reboot.

Pardon my alarm.

Landrum Haddix
lhaddix@...
http://web.qx.net/lhaddix