USB-PD Sniffing Advice

[imageryeel]

Hello All,

I'm looking for microcontroller options to sniff/monitor USB-PD communications between two devices.

I've found the chromium project: https://www.chromium.org/chromium-os/twinkie which uses linux/stm32

I'm wondering if anyone is familiar with a teensy based solution to this problem?

The USB-PD protocol is half duplex with 4b5b encoding @ 300 kbaud. I'm wondering if AltSoftSerial library on a Teensy3.2 (reported max 400000 baud) may work?

Thanks for any links/suggestions.

I posted a similar question on the arduino forums but haven't got any replies: https://forum.arduino.cc/index.php?topic=716375.msg4812791#msg4812791

 

[imageryeel]

Update, it seems like ST has some software tools (X-CUBE-USB-PD) and the STM32CubeMonUCPD tool. I haven't spent much time in the ST ecosystem so I would still appreciate any additional suggestions but I wanted to provide these links if anyone is looking for a similar solution.

https://github.com/STMicroelectronics/x-cube-usb-pd

https://www.st.com/en/development-tools/stm32cubemonucpd.html

 

[Deleted User]

Hmm. what exactly do you want to achieve by "sniffing" USB-PD?
The protocol is very well documented.

Making some non-standard communication by deliberately forging an impropriate signal and circumventing safety may either fry the devices, or at best it will just do nothing else than trigger safety and shut down the supply.

Hopefully nobody will support the evil hack that you obviously intend to do.

 

[imageryeel]

Hey Deleted User,

Nothing as nefarious as that, I just wanted to do some automation based on the PD messages, I realize I can determine the status via the VBUS voltage but I thought decoding USB-PD would be a neat way to do it.

Again, appreciate any tips.