Lpc2000

>We had pulled P0.31 down because it was the enable for a 485
>transciever and needed to be low during reset.
>
>Turns out there is an 'undocumented feature' on some of the LPC
>parts including the 2138 that will disable JTAG if P0.31 is low during
>reset. We all know about RTCLK needing to be high during reset
>for JTAG because it's documented, but P0.31 functions exactly the
>same way.

I am not sure as to how one can guarantee that P0.31 is indeed pulled high
during reset to enable JTAG debugging. I assume this would have to be done
in software running on the device, but then to get that software into
memory requires use of the JTAG port. Seems like a chicken and egg
problem. Am I missing something?
Thanks,
-BNP