ARM SWO ITM Console Bidirectional Standard I/O Retargeting

The ARM Cortex M architecture has many features which are underused, probably simply because engineers are not aware of it. SWO (Single Wire Output) is a single trace pin of the ARM Cortex-M CoreSight debug block. trace pin uses the ITM (Instruction Trace Macrocell) on ARM Cortex. It provides a serial output channel, at a high speed higher than the usual UART, because it is clocked at half or a quarter of the core clock frequency, depending on the core and implementation.

As such, it is an ideal high speed output channel to send text or data to the host. This is how it is usually used, but what is unknown to many: it can be used in a bidirectional way with the help of the debugger.

The topic of this article: how to redirect standard I/O like printf() or scanf() using the SWO ITM console: means both sending *and* receiving data over the SWO debug channel: that way I can use it as a kind of UART with a single pin only.

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NXP MCUXpresso IDE 11.7.0

It is the exam and grading time at the university, and the same time I’m preparing the lectures and labs for the new semester starting mid of February. I’m always heading for using the latest and greatest tools in my labs. A few days ago, NXP released the new version of the MCUXpresso IDE, version 11.7.0. Time to check it out…

NXP MCUXpresso IDE 11.7.0
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Tutorial: Creating Bare-bare Embedded Projects with CMake, with Eclipse included

MCU vendors offer SDKs and configuration tools: that’s a good thing, because that way I can get started quickly and get something up and running ideally in a few minutes. But this gets you into a dependency on tools, SDK and configuration tools too: changing later from one MCU to another can be difficult and time consuming. So why not get started with a ‘bare’ project, using general available tools, just with a basic initialization (clocking, startup code, CMSIS), even with the silicon vendor provided IDE and basic support files?

In this case, I show how you easily can do this with CMake, make and Eclipse, without the (direct) need of an SDK.

NXP LPC55S69-EVK with LoRa Shield
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New “MCU-Link Pro”: Debug Probe with Energy Measurement

After the release of the NXP MCU-Link debug probe, there have been hints in the Eclipse based MCUXpresso IDE that there must be another one coming. And indeed: another and more powerful debug probe is now available: the MCU-Link Pro. It is not only a debug probe but a power/energy measurement tool too, including an extra LPC804 mikrocontroller which can be used for all kind of things, like automation or scripting.

NXP MCU-Link Pro
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Visual Studio Code for C/C++ with ARM Cortex-M: Part 4 – Debug

The previous parts were about installation, project setup and building. This one is about debugging an ARM Cortex-M Microcontroller with Visual Studio Code:

Cortex-M4 (NXP K22FN512) Debugging with Visual Studio Code
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Visual Studio Code for C/C++ with ARM Cortex-M: Part 2 – Project

This is the second part of series or articles how to use the Microsoft Visual Studio Code for embedded development on ARM Cortex-M. In this part I’m going to show how to create and build a project using CMake running Make or Ninja as build system.

Building with Visual Studio a simple ARM Cortex-M Project (NXP K22FN512)
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Visual Studio Code for C/C++ with ARM Cortex-M: Part 1 – Installation

For a few months I’m learning and using Rust. I’m still learning, but I’m very impressed by the powerful and cool programming language, the vibrant ecosystem, the advanced concepts behind it and by the tools. With learning Rust I have been using the Visual Studio Code IDE and it works great for Rust. But I was wondering: could I use it for my ‘usual’ C/C++ development on ARM Cortex-M devices too? The answer is a clear ‘yes’, and this mini series of articles should get you up and running too.

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Debug Firmware Switching for the LPC4322

In “Freelink LPC4322JET100 based Debug Circuit on NXP i.MX RT1064-EVK Board” I described how to change the factory firmware from OpenSDA to the LPC-Link2 one.

Debug Circuit on i.MX RT1064
Debug Circuit on i.MX RT1064

Now it is possible to use a Segger J-Link firmware too, or to switch back to the factory default one.

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“java.net.SocketException: Connection reset”: Check your Windows Updates!

One of the most frustrating part developing embedded applications is if the debug connection fails somehow: with all the different factors like operating system, virtual machines, USB ports and hubs, debug probe and firmware a ‘connection failed’ is my nightmare. And this is probably the most frustrating parts for my students (and myself!)

I do have a growing list of tips & tricks in “Debugging Failure: Check List and Hints“, so check this list. What I just have added is an entry for

java.net.SocketException: Connection reset

It occurred for a few students when they wanted to use the on-board CMSIS-DAP LinkServer debug connection on the NXP LPC845-BRK.

NXP LPC845-BRK Board

NXP LPC845-BRK Board

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NXP published MCUXpresso SDK 2.9.0 on GitHub

There are many different aspects of Open Source projects: It is not only about the fact if the sources are available (‘open’). It is about the licensing terms (how permissible is it, what can I do with it), maintenance and continuous development (what has changed between releases), how and where is it delivered (Sourceforge, dedicated distribution, packaging) up to collaboration (how can I contribute or submit issues).

NXP has now published the MCUXpresso SDK on Github:

MCUXpresso SDK on GitHub

MCUXpresso SDK on GitHub

Something I was waiting for a long time.

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