The NXP LPC178x series is a scalable mainstream MCU, based on the Cortex-M3 core.
In case some bad code has been flashed into the device (wrong PLL init that bricks the device, ...) that makes it unresponsive to debug commands, there is no built-in mechanism that allows J-Link to regain control over the device, however the device is not lost yet.
The LPC178x series devices provide a specific pin to enter ISP mode on boot which effectively inhibits starting the user application and therefore the bad code. In order to recover an LPC178x series device that is running bad code, the following needs to be done:
- Short P2 with GND
- Power-cycle the device (make sure that LOW is sampled on P2)
- Release P2
- Start J-Link Commander, J-Flash or any other utility that supports J-Link and reflash the device