B-L475E-IOT01A is not able to enumerate as USB DFU class.

[Keyur Thumar]

I am using B-L475E-IOT01A (STM32L475VGTx) dev kit and this article for DFU and I am getting following issue.

• device is not able to enumerate as USB DFU class on my windows 10 PC

I am using flash decription as show in the tutorial.

#define FLASH_DESC_STR   "@Internal Flash  /0x08000000/02*016Ka,02*016Kg,01*064Kg,03*128Kg"

For replacing flash mem read,write api I have taken a reference from STM32L476G-EVAL DFU_Standalone example.

• bootloader code is not able jump to app location.

In my driver SCB->VTOR is not set so not changed app start location.

Can anyone please suggest what could be the reason for this ?

[Keyur Thumar]

I have further debugged this.

I have found that tool sends request for get status to device.

At that time USBD is in configured state. And DFU state is busy(4 as shown in screen shot).

 

Anyone has idea for this ? I have been stuck for this since long. Any help would be great.

@Imen DAHMEN​  can you please ?

[Imen.D]

Hi @Keyur Thumar​ ,

Maybe the problem here is caused by the HSE crystal. I recommend you these FAQs that may help you on your issue:

• DFU mode with system bootloader is not working, while USB does
• How can I use STM32CubeProgrammer to access the USB-DFU bootloader on my STM32 board?

1. How to Modify USB DFU firmware examples to work with STM32CubeProgrammer

Hope my answer helps you!

Imen

[Keyur Thumar]

Thanks @Imen DAHMEN​  I am not using HSE.