Troubleshooting • Raspberry pi cm5 USB-C otg passthrough using usb c port from UPS

Hello everyone,

##Context
I'm trying to design a raspberry pi device based on the cm5 with a waveshare nano b carrier board. This is combined with a waveshare UPS hat type D that will be modified for the tiny space of the project.
As a part of the project i would like to use one usb-c port to do OTG and to be a charging port for the UPS.

##Hardware
- cm5
- waveshare cm5 nano b carrier board
https://www.waveshare.com/cm5-nano-b.htm
- waveshare Pi 5 UPS hat D https://www.waveshare.com/product/ups-hat-d.htm

## UPS modification
Removing battery holder as there is an integrated one in my design. Soldering 5 A resistant cable to the battery points as i cannoy use the pogo pins since i'm using a compute module

## Questions
-Is it possible to use a a usb-c breakout in the UPS and the CM5 carrier board to link them in -the following way :

USB-C female port data -> CM5 carrier board usbc data
USB-C female port Vbus/Gnd -> UPS USB-C Vbus/GND
CM5 carrier board Vbus/Gnd -> UPS 5V/GND out
- Does this would interfer with the OTG mode ?
- What are the usb cc requirement while using OTG mode ?
- Would it be better to connect the 5v out of the UPS to the GPIO ?
- Does the USB-C port use Vbus sense to handle the data in OTG mode?

I would gladly appreciate any help or guidance. If this POC works, I would like to develop a carrier board that have everything mentionned before.

## Goal
Use one usb-c port for charging and OTG capabilities in my device

##Concerns
- I'm worried there will be a power backfeeding from the entry point of power :
Power in -> UPS -> CM5 carrier board
- Frying the CM5

Statistics: Posted by DnR — Tue Jan 06, 2026 10:01 am — Replies 0 — Views 22

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