Articles: #hardware

Mistakes in the Docs: UART on Raspberry Pi 5 Compute Module

8th June, 2026 4min

We have a Raspberry Pi Compute Module 5 IO Board without a monitor or network connection. How do you see what the system is doing? How to read the Linux and bootloader log? A simple answer is UART. Turns out, UART isn't so simple on the Raspberry Pi 5 and its documentation, datasheet and raspi-config is wrong in a couple of places.

Dabbling with Zephyr Driver Development: STM32 direct LCD Driver

31st May, 2026 4min

I want to use an LCD glass on an STM32WB55RG, which has an LCD direct driver in hardware. You directly connect all LCD segment and common pins to the SoC. Because I want to use Zephyr but Zephyr doesn't have an LCD driver already, I implemented one myself.

Don't forget about the Option Bytes

7th May, 2026 4min

What's the reason for a watchdog taking 23 times as long to reset the device? It turns out the Flash Option Bytes are. And a mass erase doesn't reset those.

Automatic Firmware Generation for Spaceflight Hardware based on Schematics

16th February, 2026 119min

Any satellite's Power Conditioning and Distribution Unit (PCDU) fulfills the same purpose, providing the subsystems with electrical power. However, because each satellite has a unique set of subsystems, differing PCDUs must realize differing power distributions. How do you efficiently develop firmware for such similar hardware? One approach is to group components and their PCB layout into a snippet, e.g., an Analog to Digital Converter (ADC) with supportive components. Each PCDU can reuse the same snippets arranged differently to create different power distributions. While this drastically speeds up the hardware design process, previous works failed at translating this speedup to the firmware development process. We propose the Group Netlist, a novel representation of the logical functions of hardware. This machine-readable file format enables automatic firmware generation while remaining agnostic to both programming-language and schematics editor. The electrical engineer annotates the schematics to produce not just the PCB layout but also the Group Netlist. Contrary to initial expectations, we show that the Group Netlist has uses beyond firmware generation. This includes but is not limited to harness specification and snippet based design analysis. We provide the reference implementation kicad_firmware_generation as a ready-to-use product for different projects even outside space-exploration.

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