USB sniffer tools for debugging communication between two devices

Thread Starter

DJ_AA

Joined Aug 6, 2021
152
Hi

I have a GSM module and microcontroller, they are going to be connected using a USB on a PCB.

Previously, when I required much low data rates I used UART. And to monitor communications between the two devices I simpled used a simple tool such as USB- UART Convertor- CP2102 | Makerfabs Electronics

I would connect the TX pin from this tool to TX or RX pin on my microcontroller and I would be able to see the bytes being sent or received.

Can something similar be done for USB?

As USB is impedance controlled, I believe you can not simply add a pin header between trace from module to microcontroller to intercept it.

What is the correct way?
 

panic mode

Joined Oct 10, 2011
2,113
did you check WireShark? it is piece of software commonly used to capture and analyze Ethernet traffic but for some time it seem to be offering the same for USB.
 

GetDeviceInfo

Joined Jun 7, 2009
2,082
How would intercept a USB connection, between two device?
Could you do it through a hub, I don’t know, but software sniffers do work well. I worked with several years ago to develop camera interfaces. Understanding the protocols is a must, and from there, Controlling a device is straight forward, until you run into proprietary and undocumented functions.
 

Thread Starter

DJ_AA

Joined Aug 6, 2021
152
The module , when connected to a PC, is shown as COM port, so i guess the uC will need to be host com port.
 

strantor

Joined Oct 3, 2010
5,918
I was surprised recently to find that there's not a cheap solution to this. At least not one that jumps out in a google search. I found this, which should work if speed is 12Mbps, but if it's 480Mbps then this is the cheapest thing I found. I found absolutely nothing for 5Gbps Note about both these analyzers; They should work if your two devices are connected via a USB cable and you can unplug them and insert the analyzer in between, but if it's traces on a board, these analyzers won't allow you to just probe them. I didn't find anything that would let you do that.

I can't believe something like this isn't more common for USB. Every other protocol has cheap sniffers available. I found some results on Amazon for <$70 using the search term "protocol analyzer" which claim to work on USB 12Mbps but I don't trust them so I won't link to them.
 

Thread Starter

DJ_AA

Joined Aug 6, 2021
152
All I need is to read AT commands being sent and received between uC and module over USB.
I believe this 12mbs.

Worst case scenario , i can always use my PC as bridge between the uC and module.
 

GetDeviceInfo

Joined Jun 7, 2009
2,082
All I need is to read AT commands being sent and received between uC and module over USB.
I believe this 12mbs.

Worst case scenario , i can always use my PC as bridge between the uC and module.
Why you want to do this might bring about more helpful responses.
 
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