Consolidating with VS Code

Posted on August 1, 2023 by Erich Styger

It is August 1st, and Switzerland is celebrating its National Holiday. Rather cold and rainy, so this gets me some time to catch up on things. The preparation for the coming university semester in September is in full swing, and I have the honor to take over building up a new Master of Science in Engineering education module. In the existing courses I teach on the topic of embedded systems, I do use devices and MCUs from vendors like Broadcom, NXP, STM, Nordic, Raspberry Pi and Espressif. This not only means different SDKs, but different IDEs with different debug probes.

Just a subset of different hardware kits used in different labs

Eclipse has been the common factor in the mix with all these, and with all the pros and cons, it worked very well. With NXP having released support for Visual Studio Code, adding an announcement, and other vendors going into the same direction, I took the decision that I want to migrate my lab and lecture infrastructure to VS Code.

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Using Legacy Devices with LinkServer

Posted on July 30, 2023 by Erich Styger

The Freescale K20DX128 MCU was one of the first ARM Cortex-M devices of that company (now NXP) back in 2012, and the FRDM-K20D50M board was the first ‘FRDM‘ board of a long and successful series of boards, starting back in 2013. I still have the K20 present in many of my designs. The challenge with ‘early’ or ‘legacy’ devices is that after a while, they are ‘not recommended’ any more, and it is hard to get support for them. So for example in newer tooling and software from NXP, there is no support for the K20.

MCU-Link (NXP, left) debugging FRDM-K20 (Freescale, right) board

So if you still have the K20 around, and need some newer tooling, then I have good news for you: It is possible to add that good-old-Kinetis to the list of supported LinkServer devices, so you are not stuck and can use newer debugging solutions for the K20.

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Data Converter for MCUXpresso Energy Measurement Data

Posted on July 30, 2023 by Erich Styger

The combination of the NXP MCUXpresso IDE with the NXP MCU-Link Pro debug probe implements a nifty power and energy measurement tool (see New “MCU-Link Pro”: Debug Probe with Energy Measurement). The eclipse based IDE provides a dedicated view to inspect the data collected. It can export and import data, but it is in a binary format. In this article I present a way to export and then convert the data into .csv or any other format for processing or visualizing it in different ways.

Using an open source command line tool, the binary data gets converted into a csv format, which then can be consumed by many tools, e.g. gnuplot.

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Catchpoints: Unlimited Number of FLASH Breakpoints with GDB

Posted on May 31, 2023 by Erich Styger

Embedded hardware comes with limitations, and one if it is the given number of hardware breakpoints. Depending on your MCU, 4 or only 2 hardware breakpoints are available, making debugging and stepping in read-only memory (FLASH) a challenge.

Debugging NXP LPC845 with unlimited FLASH Breakpoints using MCU-Link

Did you know that one can have ‘unlimited’ number of breakpoints in FLASH, with the help of GDB? This is very useful for extended debugging, or if you want to use breakpoints for testing?

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LinkServer for Microcontrollers

Posted on May 14, 2023 by Erich Styger

GDB is the de-facto debugging engine and debug connection for micro-controllers these days: it is versatile and with its client-server architecture very flexible and powerful, and pretty much every debug probe and vendor (PEMICRO, SEGGER, OpenOCD, pyOCD, …) offers it. But a GDB server or command line implementation was not available for the NXP LinkServer family of debug probes (LPC-Link, MCU-Link, MCU-Link Pro). This has changed now: LinkServer is available as command line tool and can be used as GDB Server:

With the new LinkServer package I do not only get a gdb server implementation: I have now a command line tool I can use for automation and all kind of different things: programming boards, erasing flash, and so on.

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Different Laser-Cut Enclosures for the MCU-Link

Posted on April 11, 2023 by Erich Styger

The MCU-Link debug probe comes without an enclosure. To protect the hardware against ESD issues, I had created a 3D printed enclosure for it. That one worked fine, but takes some time to print it. If you have to build many enclosures for a full classroom setup, then a laser cutter is much faster. And to create some variations, I have decided to cut it with different materials and colors. To be environment friendly, extra glue is needed, and with recycled PMMA, different colors are possible too.

Different laser-cut enclosure: wood, and red, transparent, blue and green PMMA

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ARM SWO ITM Console Bidirectional Standard I/O Retargeting

Posted on January 29, 2023 by Erich Styger

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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