PORTS Forum

Ports and Interfaces => USB => Topic started by: ftariq68 on October 31, 2011, 11:02:40 am

Title: Reset USB to switch to a different device behavior
Post by: ftariq68 on October 31, 2011, 11:02:40 am

I would like to send a reset command to a microcontroller USB system such that when the device recieves a reset command it not only resets the microcontroller but changes the descriptors so that it appears as a different device.  How can I get the windows to re-enumerate?  Do I have to unplug and plug the USB to do a re-enumeration?  Is this the only way?  I want to leave the USB cable plugged in to the PC and somehow get the enumeration to happen again using soft reset of some sort.

Any help will be greatly appreciated.  Thankyou in advance for your assistance.

Title: Re: Reset USB to switch to a different device behavior
Post by: Jan Axelson on October 31, 2011, 11:15:42 am

The device has to emulate detach and re-attach by electrically removing and reattaching the pull-up resistor on D+ or D-.

Jan

Title: Re: Reset USB to switch to a different device behavior
Post by: ftariq68 on October 31, 2011, 12:13:51 pm

Thanks a lot.... That is it...  :)