USB: Delay plug-and-play device detection in Windows

[spigeon]

Posted on October 23, 2008 at 12:52

USB: Delay plug-and-play device detection in Windows

[spigeon]

Posted on May 17, 2011 at 09:56

Nah, forget it, my bad.

My hardware design should have incorporated a GPIO to enable or disable the pull-up resistor on USBD+ (like on the STR912-SK).

[spigeon]

Posted on May 17, 2011 at 09:56

Hello,

I wrote a bootloader for the STR912, sitting in BANK1. The main application sits in BANK0, and incorporates a virtual COM port via the USB stack.

Now, I don't have enough code space to incorporate the USB stack in the bootloader, and the bootloader takes about 200 milliseconds before launching the application (there are many reasons for this, which I won't go into).

During these 200 milliseconds, Windows detects the device because of a pull-up resistor on USBD+, starts plug-and-play, which fails because the bootloader (which is still running) does not contain a USB driver.

Is there a way, via a few lines of code, to force the USB transceiver to drive USBD+ low, hence disabling plug-and-play until the main application has started ?

Thanks!

Steph

[milton]

Posted on May 17, 2011 at 09:56

Hey!

I am writing a boot loader as well; in DFU mode, exactly with the same characteristics then your in terms of switching bank's.

My question is about he USB part, which USB class you use to communicate with your device? HID? MASS STORAGE? and the SUBCLASS? BULK? INTERRUPT?

What about in the PC side, do you use a specific driver or you can just you the windows libraries?

Do you have a good example to start with?

Thanks and sorry for so many questions.