Modern MCUs like the NXP Kinetis have security features which prevent reverse engineering, but can ‘brick’ devices too. Depending on the settings, it prevents read-out from the FLASH or reprogramming the device. While some of the protection is (mostly) not by-passable by design, in many case the devices looks like ‘bricked’ but still can be recovered. In this article I’ll get you some ways for a (hopefully) successful recovery.
While developing applications, it can happen that things go wrong. And in my case I ended up with two LPC55Sxx EVK boards on my desk, which seemed not to be usable any more. The issue: the boards were not accessible with the debug probe, because right after main they muxed the pins in a wrong way :-(.
The standard GDB debug connections (both on-board and off-board) were not able to regain access of the board, because the MCU was running into the fault condition pretty much right out of reset.
Luckily, after a lot of trial-and-error, I have found a way to recover them.
Continue readingUniversity exam grading are all done now and results are in the system, and it is already time to prepare for the fall semester. I always try to use the latest and greatest tools in my courses, and the NXP MCUXpresso IDE 11.4.0 just came out. So time to have a look and explore the changes and features.
If a Cortex microcontroller is unresponsive to a debug connection for various reasons, then this trick might help to recover that device for you. All you need is a debug probe from PEMICRO and a utility.
The LPC55S69-EVK board comes on-board debug probe. The board includes the LPC4322JET100 device which acts like NXP LPC-Link2 debug probe:
LPC4322JET100 on LPC55S69-EVK
But it is easily possible to use the board with an external debug probe or re-program the onboard one as a SEGGER J-Link debug probe.
Eclipse for C/C++ (CDT) offers two different ways to get out of a debug session: Terminate and Disconnect:
Terminate and Disconnect
The terminate and disconnect behaviour is not standardized, and varies between Eclipse distributions and debug connection. This article is about how things are handled in MCUXpresso IDE, and how I can influence the behaviour.
MCU on Eclipse 