Change usb configuration on the fly in STM32F103

[lesterm]

Posted on November 10, 2011 at 00:14

I am working updating and existing project that has 2 modes of running the usb in our product.  One is a serial port mode that is working as expected, and an emulated msd cdrom that is also working as expect.

What I am trying to add is a way to dynamically switch between these two configurations on the device.  I have attempted to perform a reset similar to those in the example projects for usb serial and msd, but the host computer does not see a device change.  Is it possible to change the configuration on the fly without electrically disconnecting from the host and reenumerating?

#stm32f103-usb

[domen23]

Posted on November 10, 2011 at 13:32

Transistor that enables, disables the usb speed selection pull-up?

[lesterm]

Posted on November 10, 2011 at 18:25

Domen,

That would the the preferred way for sure, but unfortunately this is an existing product that has D+ hard pulled up to our primary vreg... so if the powers on, then the usb is pulled up.  I was wondering if there is a way to reconfigure it without reenumerating?

Les