Controlling an EV Charger with Modbus RTU

The year 2022 is coming to an end, and I have spent some time today on a little side project. It is about making an Electrical Vehicle (EV) wallbox charger accessible over Modbus RTU. It is not finished yet, and I plan to publish more articles on it, but I can share that I’m able to access and control the Heidelberg EV charger with a Raspberry Pi Pico W (Dual Core Cortex M0+), NXP K22FN512 (Cortex M4F) and LPC845 (Single Core Cortex M0+):

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Fixing “REENT malloc succeeded” Assertion

One little nasty assertion in the GNU standard library appeared a few days ago, kind out of nowhere, reporting “REENT malloc succeeded”:

Obviously it was caused by the call to srand() which sets the ‘seed’ for the standard library (pseudo) random number generator. The assertion happens as well later for calling the rand() function.

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Resurrecting ‘bricked’ NXP Kinetis Devices

Modern MCUs like the NXP Kinetis have security features which prevent reverse engineering, but can ‘brick’ devices too. Depending on the settings, it prevents read-out from the FLASH or reprogramming the device. While some of the protection is (mostly) not by-passable by design, in many case the devices looks like ‘bricked’ but still can be recovered. In this article I’ll get you some ways for a (hopefully) successful recovery.

J-Link EDU Mini recovering a tinyK22 with needle adapter
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DIY Split-Flap Display

Split-flap displays are electromechanical display devices, which were common in airports or railway stations a few years ago.Unfortunately, most of them are gone and replaced by LED displays. Why not create a DIY version of it?

2×10 Split-Flap Display
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Key-Value pairs in FLASH Memory: file-system-less minINI

Many embedded systems application need to store some kind of data in a persistent way: calibration values, settings or log information. For a smaller amount of data, using an external memory or file system is an overkill. In many system I’m using minINI to store key-value pars in in a ‘ini-file’ way, but it requires the use of a file system of some kind. minINI is great and efficient, and makes getting and storing data really easy. But for simple cases, a single FLASH memory page or sector is just all what I need. Instead managing that page directly, why not using minINI without a file system?

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

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

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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Full Bathroom Remodeling (with the Help of a 3D Printer)

This is about one of my ‘long running projects’: I happily can report that the missing last piece has been installed after 16 months from the start of the project: the ‘3D-Printed-Supported-Driftwood-Bath-Tub-Shower-Gel-Holder’ 🙂 :

This is the ‘official finish’ of a complete bathroom renovation and remodeling. It has been a joint project with the help of friends, contractors, my family and my brother in law (who is an outstanding carpenter and cabinetmaker), plus the Ultimaker2 3D printer which contributed many ‘background and hidden’ features.

I invite you to a virtual time travel. I hope you enjoy it and get inspired….

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tinyK22 Board Rev 1.3 released

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

tinyK22

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