Erich Styger's MCU-Link-MR Promises Easier Debugging of Pixhawk, PX4 Drone and Robotics Hardware

Embedded engineer and professor Erich Styger has designed an open source alternative to the NXP MCU-Link CMSIS-DAP Debug Probe tailored for work on drone and mobile robotics projects — targeting Pixhawk and PX4 devices in particular: the MCU-Link-MR.

"With the Pixhawk 6x-RT there is a powerful flight controller, using the NXP i.MX RT1176 dual-core processor. While this and other controller hardware do offer a hardware debug probe, it is not a simple task as there are different pin-outs and connectors, making debugging a mess with different cables and adapters," Styger explains of the problem he set out to solve.

"To simplify this, I have now [designed] a unified debug CMSIS-DAP debug probe using the NXP LPC55S69 as processor, with all the different headers and UART adapters included: the MCU-Link-MR (Mobile Robots) debug probe."

Styger's redesign, brought to our attention by Adafruit, is based on the NXP MCU-Link CMSIS-DAP Debug Probe — but, in addition to being released as open hardware, comes with tweaks designed specifically for debugging robotics hardware. Key to this is the addition of new debug headers, allowing easy interfacing with control boards featuring Pixhawk "full" and "mini" debug ports.

This isn't the first time Styger and students have riffed on the MCU-Link to create something better-suited to a given task. Back in February this year he unveiled the MCULink-Mini, designed by Dario Scheuber and built to put the capabilities of NXP's original into a smaller form factor while retaining full firmware compatibility. Prior to that, Styger had designed the Raspberry Pi RP2040-based picoLink, another option for CMSIS-DAP debugging.

"The v0.1 hardware has been assembled and tested," Styger says of the MCU-Link-MR. "Debugging works fine, plus the UART connection on the UART header. But the UART on the other debug header connections are not functional because I've made a mistake with the protection diodes for it. That’s why there is a v0.2 design underway which has this fixed. I should get that version middle of next week/mid of May operational."

Full details are available on Styger's website, while design files — including for the revised v0.2 — are available on GitHub under the permissive MIT license.