Intercept USB Traffic Using A Kinetis

[weblar]

Hi,

I'm currently investigating the possibility of intercepting and passing on USB traffic from a number of devices.

What I want to be able to do is, take a Kinetis device with a USB port and connect it to a computer. Then, take the second USB interface (connected to a USB transceiver using ULPI) and plug an external USB device in, such as an MSD device. I want to then be able to intercept the traffic on this second port and forward it on to the PC - almost like a pass-through device or what protocol analysers do.

I guess what I'm wanting to know is, should this just be a simple case of forwarding on the USB frames from the ULPI device to the USB device controller on the Kinetis or (undoubtedly) will much more be involved?

Thanks for any advice in advance.

Regards,

Kevin

[Jorge_Gonzalez]

Hello weblar:

We just noticed this unanswered question, sorry.

I think the application you wanted to implement such as pass-trough or similar to a USB sniffer with Kinetis is not possible. The processing overhead would be too much for the Kinetis MCU to catch the USB frames and still hold the connection between the MSD device and the PC, so there would be major delays.

A different idea would be using a MCU such as Kinetis K70, which has both a Full-Speed and High-Speed interfaces. One of them would act as device, while the other would be host. Obviously this is not a pass-through either, but it would serve to communicate data from a specific USB device to a PC using the Kinetis K70 as intermediate.

MQX v4.1 has an example like this. If you download and install MQX you will find such example in:

C:\Freescale\Freescale_MQX_4_1\usb\common\examples\hid\keyboard2mouse

Regards!

Jorge Gonzalez