USB Device to Host Briding for CDC-ACM Host and Device Drivers

[ramakrishna]

Hello All,
               We are developing an embedded Application, which is used to bridge the USB Device and Host Ports. We are using the AM335x Processor (Hardware) and Ti's Starter ware SDK. The SDK has minimal support to USB and the Description was not clear. We saw some posts regarding the same in this forum and cleared that this work is feasible.The Device is 3G Module(CDC-ACM Class ), which connected to the Host of AM335x and the device side of AM335x is connected to the HOST PC. We have to emulate the 3G Device functionalities in the AM335x Device Side.
                We are facing some problems during integration of firmware(Device and Host). The Device side of AM335x is Working Well up to some time, after that Hanging occurs on terminal.We saw on the logs (in wire shark)that The Host PC will not poll the BULK IN Endpoint to accept the data. Please guide some approach to achieve the task of bridging the USB Ports.
                  Is there any Hardware (Chip) and firmware for USB Device to USB Host Bridging? 

Thanks & Regards
Rama Krishna     
               

   

[Tsuneo]

We saw on the logs (in wire shark)that The Host PC will not poll the BULK IN Endpoint to accept the data.

Do you know how the polling of the bulk IN EP looks like on WireShark (software sniffer)?
WireShark should show just single pending request (URB) to the bulk IN EP, while the polling actually occurs on the hardware (PC host controller). If you would run a hardware analyzer on the bus, you could see the polling (ie. repeated IN-NAKs), as you expect.

What do you see on WireShark around the bulk IN?
- pending URB : the bulk IN EP of the device side of the bridge is not fed any packet by your firmware.
- transaction error: the bulk IN EP is not enabled on the device side of the bridge.

Tsuneo

[ramakrishna]

Hello Tsuneo,
                      I don't know about the how wire shark works on BULK EP's, but thanks for your inputs.I will go ahead with your suggestions.

1.Will u please tell me How the Hardware analyzer works?   
2.Is it a Hardware chip or Software tool?

Thanks & Regards
Rama Krishna

[Jan Axelson]

Here are links to hardware and software analyzers:

http://janaxelson.com/development_tools.htm#analyzers