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Question asked by chen.frank.003 on Jun 4, 2016
Latest reply on Jun 24, 2016 by chen.frank.003
Hi everybody,

I got a problem to implement USB CDC to STM32F407IG. Although looking into all the post here, still not solve my problem.

I am using self-made board with  STM32F407IGT6, The sch is simply connect as
     MCU          USB connector
     PA11          D-
     PA12          D+

     without VBUS sensing.

This board working fine by load tilz0R's website precompiled hex file. So I assume that the design/layout of hardware board is correct. Then I tried many kinds of setting under STM32CubeMx , with disable VBUS-sensing or even Connect PA9 to USB-VBUS on my hardware board. All fall to PC response "unknown device" when plug in to PC USB port. 

Do someone have experience on similar situation?

My developing environment is
- MCU: STM32F407IGT6
- STM32CubeMX V4.15.0. to generate USB_FS_CDC code
- WIN7

btw, by STM32CubeMx to generate code for my another board which used STM32F103 is working fine. I am still wondering what the difference between STM32F407. Although I tried to have same pull-up 1.5K resistor for STM32F407 board as STM32F103 board did, still fail (or get worse).