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STM32L4 CDC handler

1123
Associate II

Hi all,

I am now experiencing problems with USB stuck.

I am using an STM32L433CC MCU.

There are two blocks in Flash, one is Bootloader and the other is API code.

Mainly at the beginning I entered the bootloader and can clearly know that USB can work.

Also know that when you want to jump to the API code, I should give the NVIC to disable and USB clock disable.

The picture below is my bootloader and Jump function

0690X000008w1EzQAI.jpg

0690X000008w1F4QAI.jpg

However, when I jumped to the API code, I stuck in USB_DEVICE_Init(); there was no action at all.

After that, I will get USB_DEVICE_Init(); and the MCU will work normally.

So I am wondering if I have missed any steps.0690X000008w1F9QAI.jpg

In addition, I suspect that the circuit may also have problems.

This is a USB circuit diagram.0690X000008w1FEQAY.png

But the STM32L4 has extra VDDUSB power supply. Normally, I should connect VDDUSB to the VCC mini port.

Still there is no difference at all.

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