STM32F4 USB device library - won't recoginize device on reset

marknorton9 · ‎2012-11-20

Posted on November 21, 2012 at 01:46

Hi All,

I am having a problem the STM32F4 USB library labeled version 2.1.0. If I start the device and then plug in the USB, all is good. If I have the USB connected and start the device, my PC will not recognize the device. I created a composite MSC & CDC device. However, I tried just the supplied MSC and that will also not work. I am not using the VBus to signal the stack (Port A.9). Any ideas?

marknorton9 · ‎2012-11-21

Posted on November 21, 2012 at 13:44

I think I have found the problem or at least a work around. The 1.5K pullup resistor on the USB_DP pin is always tied to 3.3V in our design. If I set this pin to an output low after reset and allow the stack to configure the pins then the device is recognized. I looked at the STM32F40G eval schematic and see that this pullup is enabled through the USB Vbus signal. I don't see how connecting it in this mannor would be any different since Vbus would have the pullup enabled on reset as well.

harasak · ‎2013-03-03

Posted on March 03, 2013 at 17:30

Hi Mark,

I am trying to make a composite device MSC + HID. May I ask you how you made your USB composite device? The USB libs (2.1.0) look like prepared only for an implementation of one intereface (class).

//USB Initialization:

USBD_Init(&USB_OTG_dev,

#ifdef USE_USB_OTG_HS

USB_OTG_HS_CORE_ID,

#else

USB_OTG_FS_CORE_ID,

#endif

&USR_desc,

&USBD_MSC_cb, //How can you put here more callbacks than for one class???

&USR_cb);

Do I have to modify even USB core files where the argument is defined ? How?

Thank you.

Best Regards,

harasak