Category Archives: Tutorial

Position-Independent Code with GCC for ARM Cortex-M

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Welcome to ‘Alice in Wonderland‘! For a university research project using an ARM Cortex-M33 we are evaluating position-independent code as way to load applications or part of it with a bootloader. It sounds simple: just add -fPIC to the compiler settings and you are done.

Unfortunately, it is not that simple. That option opened up a ‘rabbit hole’ with lots of wonderful, powerful and strange things. Something you might not have been aware of what could be possible with the tools you have at hand today. Leading to the central question: how is position-independent code going to work with an embedded application on an ARM Cortex-M?

Let’s find out! Let’s start a journey through the wonderland…

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Visual Studio Code for C/C++ with ARM Cortex-M: Part 7 – FreeRTOS

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This is a new article in my series about using Microsoft Visual Studio Code: After installation, project setup, building, debugging, setting up a kit and IntelliSense. This one is about setting up and using FreeRTOS:

Microsoft Visual Studio Code with Debugging FreeRTOS application on ARM Cortex-M
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Finding Memory Bugs with Google Address Sanitizer (ASAN) on Microcontrollers

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Dangling pointers and memory corruption problems are nasty issues for any developer, and usually hard to find and locate in the code. Luckily Google has developed an open source tool to solve such issues: the Address Sanitizer (ASAN). The tool is available for x86 and other desktop style architectures, including Android and Linux. This article describes how ASAN can be used for an embedded target, e.g. ARM Cortex-M4 or similar.

Catching memory errors on ARM Cortex-M4F with ASAN
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Placing Code in Sections with managed GNU Linker Scripts

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Managed linker scripts are great on one side: the simplify the otherwise complex GNU linker script handling. On the other side it requires knowledge how to tweak them in case ‘non-standard’ behavior is needed.

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Visual Studio Code for C/C++ with ARM Cortex-M: Part 6 – IntelliSense

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The previous parts were about installation, project setup, building, debugging and setting up a kit. This one is about setting up IntelliSense for Cross Development in Visual Studio Code which allows for browsing symbols or code completion:

Code Completion in Visual Studio
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SWO with ARM Cortex-M33

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One major concern of embedded system development is performance. Microcontroller have more MHz than in the past, but embedded applications are all about timing and real-time aspects.

The challenge is: how to get data off the target in realtime? SWO can help with this….

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Recovering Cortex-M Microcontroller with a Power Glitch

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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.

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Using FatFS and MinINI with the NXP LPC55S16 EVK

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For a research project we selected the NXP LPC55S16 but because it has due the silicon shortage it is not available probably for the next 52 weeks (yikes!) we can use the EVK Board.

The FatFS file system from Elm Chan is the de-facto file system for many embedded systems. As such it comes integrated with silicon vendor SDKs like the NXP MCUXpresso SDK. The problem is that the SDK only has examples for things on the board, and because that board does not have a SD card socket, no example for using FatFS with an SDK card is provided :-(. So I had to create one, and you can get it from GitHub.

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Visual Studio Code for C/C++ with ARM Cortex-M: Part 5 – ToolKit

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The previous parts were about installation, project setup, building and debugging. This one is about defining the ‘tool kit’ so I can make use more of the CMake infrastructure in Visual Studio Code:

Tool Chain loaded in Visual Studio Code
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