Lpc2000

Hello Brendan Murphy,

On our LPC2138-based design, we noticed too that you cannot use a pin
as EINT and GPIO at the same time, and we used the same work-around:
reconfigure the pin to GPIO after detecting the interrupt.

So far, only one board (out of approximately 20) gave the "spurious
interrupt" that you described, and on this board, the spurious
interrupt goes away when we bend the board (very) slightly. Our
hypothesis was that there is a problem in the PCB, and that perhaps
some ground or power wire is floating.

In your message, you mention that the spurious interrupt occurs
"depending on the mode of the interrupt and the state of the pin". I
am interested in the conditions that the interrupt does and does not
appear.

If your hypothesis (that this spurious interrupt is a feature/property
of the LPC2000 series) is correct, then I will have to consider
implementing a work-around in the firmware. But if our hypothesis
(that this is due to a broken PCB or a design error in the PCB) is
correct, you may want to review your PCB.

Kind regards,
Thiadmer Riemersma