PORTS Forum

Ports and Interfaces => USB => Topic started by: danwaqar on October 26, 2022, 02:02:50 pm

Title: USB binterval
Post by: danwaqar on October 26, 2022, 02:02:50 pm

In my composite USB device (HID+Audio)
I am seeing that setting the speaker (OUT) endpoint bInterval to 1 on USB 2.0 Speed and USB Audio 1.1 spec
The device works fine on Linux but on Windows no streaming. Upon inspection I saw no output packets going from Windows host machine to my USB device. Why is that?
As per spec Windows should recognize the binterval 1 which is a packet every 125us.
Please guide

Title: Re: USB binterval
Post by: Jan Axelson on October 28, 2022, 10:39:42 pm

A protocol analyzer may help isolate the problem. Start by ensuring that the device enumerated successfully.

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

Title: Re: USB binterval
Post by: danwaqar on November 04, 2022, 01:16:12 pm

from this link

https://www.freelists.org/post/wdmaudiodev/USB20-High-speed-audio-device-for-windows-XP


I found the reason . There is no issue with my device rather limitation in Win audio usb driver with binterval 1

if device is USB Audio Class 1 then the binterval 1 which utilizes HS USB to full extent will not work. The USB audio class 1 will only work at usb FS. The way out is to have USB audio Class 2.0 implemented. My question is can I just do it by modifying the descriptors?

Title: Re: USB binterval
Post by: Jan Axelson on December 16, 2022, 05:34:37 pm

Check to see if audio 2.0 has additional required class requests.