Content originally posted in LPCWare by lpcxpresso-support on Wed Feb 17 11:05:41 MST 2016
You didn't mention if this is custom or NXP hardware.
A couple of questions:
1. Is your application using any of the CRP settings?
2. Does your application on purpose, or by accident redirect any pins used for debug signals?
If you can't recover your board by booting into the ISP, you might still be able to erase your part using FlashMagic. Any CRP setting of 1 or above disables debug. If you've done either of the above, once you've erased flash you should be able to recover provided the offending code is disabled/removed.
After erasing flash, if you find JTAG/SWD debug is still not viable, then your debug circuit is probably damaged. Such damage is often static related, although it's sometimes possible to damage the debug circuit by mis-socketing the debug ribbon cable.
Thanks and regards,
LPCXpresso Support