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.
Debugging FRDM-KL25Z with 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 :-).
Batch Programming Boards with MCU-Link
A very useful feature in Eclipse is Ctrl+Shift+L which lists all the available shortcuts:
List of Shortcuts
Pressing Ctrl+Shift-L again will open up a dialog where I can configure them. But what if the shortcut or action is not listed there?
The NXP MCUXpressso IDE Release V11.2.1 gave a hint about a coming new debug probe, the MCU-Link which is available now:
MCU-Link in 3D printed enclosure debugging the LPC845-BRK Board
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.
Azure RTOS 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)
Running FreeRTOS with reentrant newlib
If you are a regular reader of my articles, you probably know that I’m using FreeRTOS in most of my applications, for obvious reasons. But clearly this is not the only RTOS out there. After Microsoft had acquired Express Logic back in April 2019 things kept quite for a while. To me the crown jewel of Express Logic is the ThreadX RTOS. But recently Microsoft is pushing more and more the ‘Azure Sphere’ and trying to monetize the ‘IoT’ (I apologize for mentioning that overused acronym) application space and providing it now free for devices from selected partners which includes NXP now.
Debugging with ThreadX in MCUXpresso IDE
If having a boot loader running on a micro-controller, it is very useful if both the boot loader and the loaded application can be debugged together:
Bootloader with Application Code
Implementing low power in embedded applications implemented can be challenging. Measuring current consumption is a first step to see if the software changes indeed have an effect on the current consumed. The PEmicro Universal Multilink FX debug probe comes with a useful feature to provide power to the target and the same time to measure the current consumption and to show the current used in the Eclipse IDE:
PEmicro power measurement
The tinyK22 board is a tiny micro controller board we use at the Lucerne University of Applied Sciences and Arts. It is used in many research project, used in lectures and labs and used in most student projects. Because there was no small and breadboard friendly NXP Kinetis board with a debug interface available, we developed one featuring the NXP K22FN512, named the ‘tinyK22‘. Because of the success and high demand we stated a new large production run and used this to upgrade the board to the new Rev 1.3: you might notice already the color change :-).
tinyK22
MCU on Eclipse 