AnsweredAssumed Answered

Cant program flash or debug

Question asked by Johnni Friis on Feb 6, 2017
Latest reply on Feb 7, 2017 by Johnni Friis

LPC1837JET256, chip rev.'A', I'm using Keil and ulink2 (SWD) on our hardware. I can not download to flash.

I get errors like: "Could not stop Cortex M device".


I have verified signals in the debug connector. Pin10 was not reset, it has been changed.  

Got 10K pullup on SWDIO, SW0, TDI, 10k pulldown on SWDCLK. and TRST is floating.

Reset is 10k pullup and 100nF to GND, and a switch to GND.

I checked DBGEN, it is at 3.3V.

ISP (P2_7 - A9 in my case) is at 3,3V during reset and else at 0,3V. See below too.


If I remove the reset signal, I can program flash and the 6 LED blinks as expected. Something is working....

I have compared the debug interface on my board with the MCB1800 EV-board and it seems to be identical.

If I switch to MCB1800 (LPC1857JET256, chip rev '-') I can program and debug, so the ulink2 seems to work, project settings seems to be ok. There must be some kind of difference between the two.


If I set ISP low (by a DIP switch) and toggels reset, no LEDs are blinking - it is in ISP mode. If I set DIP sw off and toggles reset the LEDs starts blinking - program running. So the ISP seems to be ok. I wonder why it is low after reset?


Attached first 3 pages of my diagram and a more detailed description in word.


Any ideas would be highly appreciated