Something what I say quite often is: “Google is your friend”. It means that the answer to many questions can be found with an internet search engine. And I have to admit that I have to ‘google’ my own articles to find solutions for problems I feel I have seen in the past too :-).
But for the one problem below I did not find anything: not on my own blog, and not anywhere else in the internet:
I’m in the middle of the university exam season: means writing exams and do grading. The same time the new semester is approaching too and I need to prepare the new course material. For the classes using NXP parts I’m using the Eclipse based MCUXpresso IDE, and I just received the announcement that a new version V11.3.0 is available: time to check out what is new.
I had a few of PCBs left over from the V3 MetaClockClock, and originally I planned to finish a build with them by the end of 2020. But as always: things took a bit longer than expected, so I finally finished it today on the first day of the year 2021.
The build uses the same hardware as in the previous V3, but instead of an ‘artistic’ canvas background I decided for a more natural and wood design:
The NXP MCU-Link is a powerful $10 debug probe for ARM Cortex-M devices and works with the NXP LinkServer for debugging. The LinkServer does not an implement a gdb server, so it limits its usage e.g. for scripting or command line debugging. But as MCU-Link is also a CMSIS-DAP compatible debug probe, I can use it with OpenOCD which is open source and implements a GDB server. This article shows how I can use it with the MCU-Link.
The MCU-Link is a $10 CMSIS-DAP capable debug probe which works out-of-the box with the MCUXpresso Eclipse based IDE. This is great for development, but how can I programming with the push of a button or a script? The answer is no: there is an easy way to use the debug probe outside Eclipse from a shell script, and you can use that MCU-Link probe to do the job. This is especially useful as with the example below where I have to program 60 boards this week-end :-).
The NXP Kinetis devices implement a UID (Unique ID) for each device, using the ‘Unique Identification Register) which is part of the SIM (System Integration Module):
SIM Unique ID (NXP K22P144M120SF5RM.pdf Reference Manual)
While this number should be unique, I was wondering last week why students in the labs reported the same UID for multiple robots in the lab. So maybe this number is not so unique as it should be? Continue reading →
Having visibility and insights into a running system is highly valuable or critical: not only for optimizations but as well to verify the system design and behavior. In Getting Started with Microsoft Azure RTOS (aka ThreadX) I showed how to quickly run Azure RTOS. This article is about getting trace out of an ThreadX application and show it in TraceX.
Reentrancy is an attribute of a piece of code and basically means it can re-entered by another execution flow, for example by an interrupt or by another task or thread. This is an important concept and still a lot of code ‘in the wild’ does violate reentrancy. As a result the application crashes immediately in the best case. Worse it crashes randomly or even worse it behaves incorrectly 😦 .
Reentrancy is always a concern if using standard library functions, including printf() or malloc(). FreeRTOS offers a reentrant wrapper to the standard malloc() and free() (Memory Scheme 3)