Developer Sebastian “dos” Krzyszkowiak has designed a device that goals to make it simpler to experiment with USB Energy Supply, providing the power to smell the connection or act as a man-in-the-middle machine — or to entry a USB Sideband Use (SBU) debug console on otherwise-uncooperative devices: the Debubo.
“[Debubo is] a four-layer PCB with [STMicroelectronics] STM32G071CB microcontroller geared up with two USB Energy Supply interfaces and [WCH Electronics] CH342 twin UART to USB (CDC ACM class) converter,” Krzyszkowiak explains. “[The] STM32 can talk by way of Energy Supply protocol over each USB-C plug and ‘DATA/PWR’ USB-C receptacle, that are straight related to one another to move energy and USB 2.0 knowledge by way of.”
If you happen to’re experimenting with USB PD units, Debubo will help unlock hidden secrets and techniques. (📷: Sebastian “dos” Krzyszkowiak)
At its easiest, the Debubo sits in the course of a USB Energy Supply connection — a comparatively latest addition to the USB commonplace, which permits units to barter greater voltages and amperages than a conventional USB connection can provide — and permits the communications to be monitored. Flip modes, although, and a secret energy is engaged: the power to entry units’ debug consoles.
“[The] CH342 gives entry to three.3V UART on [the] USB-C plug’s SBU [Sideband Use] pins,” Krzyszkowiak writes. “This permits to entry debug console on units that solely expose it on SBU pins after coming into an alt-mode or sending customized VDMs [Vendor-Defined Messages] over PD [Power Delivery]. Debubo may also be used as a Energy Supply sniffer/injector (as a man-in-the-middle).”
The board also can act as a man-in-the-middle for sniffing or command injection. (📷: Sebastian “dos” Krzyszkowiak)
There are just a few caveats to the board’s design, although: Krzyszkowiak warns that it requires that each side agree on the negotiated voltage as a way to keep away from injury, you may’t ship or pass-through Quick Function Swap signaling although it may be obtained, and there is no scarcity safety on the CC traces — that are solely 5V tolerant, and will lead to injury when utilizing greater voltages.
Krzyszkowiak has launched the Debubo design, as a KiCad venture and Gerbers for manufacturing, on GitLab below the reciprocal GNU Common Public License 3.