Content originally posted in LPCWare by NXP_USA on Tue Feb 23 01:33:35 MST 2010
Quote: richas
In playing with the settings I seem to have created two LPCxpresso boards that will no longer enter debug mode.
When I try to connect I get a "Invalid ACK returned from DP access".
I try a co-workers board and it works.
I had been playing with the settings in the system_LPC11xx.c file in the CMSIS project, namely those pertaining to the PLL and clock source.
Any way to recover these boards or are they bricks?
In the process of trying to get them to work I reinstalled the IDE. :P
Rich
Tie the ISP pin (P0.1) to ground. Upon reset/power-up, this will cause the board to enter ISP mode instead of running the user flash code. At this point the board can be reprogrammed by ISP through the UART, or the SWD port (driven by LPC-LINK) can take control of the board while it is running the ISP firmware and erase/program the flash memory.
-NXP