Re: [libusb] Endpoint 0x81 Not Responding

[Alan S. <st...@ro...>]

On Tue, 29 Mar 2016, Phani Kumar wrote:

> In 9.1.1.5 section of  USB 2.0 Specification, it is mentioned as below:
> 
> 9.1.1.5 Configured
> Before a USB device’s function may be used, the device must be configured.
> >From the device’s
> perspective, configuration involves correctly processing a
> SetConfiguration() request with a non-zero
> configuration value. Configuring a device or changing an alternate setting
> causes all of the status and
> configuration values associated with endpoints in the affected interfaces
> to be set to their default values.
> *This includes setting the data toggle of any endpoint using data toggles
> to the value DATA0*.
> 
> Can you please tell me what is the meaning of "
> 
> *This includes setting the data toggle of any endpoint using data toggles
> to the value DATA0"?*

It means when you send a Set-Config or Set-Interface request, the data
toggles of all the affected endpoints are set to 0.  The affected
endpoints are all endpoints for Set-Config, and all endpoints in the
selected interface for Set-Interface.

Alan Stern