PORTS Forum

Ports and Interfaces => USB => Topic started by: j99yu on October 19, 2016, 09:42:14 pm

Title: Halt condition in control transfer after detaching device from hub
Post by: j99yu on October 19, 2016, 09:42:14 pm

I'm trying to add USB hub support to an Atmel microcontroller with USB host. I was able to get the hub to enumerate as well as a second device attached to the hub. When I detach the latter device, the host gets notified (via the status change interrupt endpoint) but I get a halt condition when trying to send a Get Port Status and can't figure out why. What could be possible causes and is there anything that should be done between receiving the interrupt IN transfer and sending a control transfer?

Title: Re: Halt condition in control transfer after detaching device from hub
Post by: Jan Axelson on October 21, 2016, 09:55:35 am

Do you mean that the endpoint is returning STALL? If so, there is likely something wrong with the request.

See 11.24.2.7 in the USB 2.0 spec.