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Treacy Yao
Treacy Yao
Associate III
November 20, 2019
Solved

re-enumerate USB on STM32F103

CDC function run normally. But if MCU reboot(For example, USB connect to PC and reboot MCU), USB will not recongnized. It will return to normal if I remove USB then insert it again.

So I want to add re-enumerate function to let device re-enumerate though USB always in PC.

  1. How to modify the code to realize re-enumerate function?
  2. I try to set PA12 low to high before USB init. Device cannot run. Maybe blocking
This topic has been closed for replies.
Uwe Bonnes
Uwe BonnesBest answer
Chief
November 20, 2019

If you want a work-around that is not standard compliant, switch PA12 to GPIO/Open Drain, set it low for about 10 ms, and than set up USB. This works for Bl*ckm*gic debug probes.

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3 replies

Uwe Bonnes
Uwe BonnesBest answer
Chief
November 20, 2019

If you want a work-around that is not standard compliant, switch PA12 to GPIO/Open Drain, set it low for about 10 ms, and than set up USB. This works for Bl*ckm*gic debug probes.

    Treacy Yao
    Treacy YaoAuthor
    Associate III
    November 20, 2019

    I tried. But if I add low PA12 to my code（MX_GPIO_Init）. Then my FW cannot run. I don't know why

    waclawek.jan
    waclawek.jan
    Super User
    December 4, 2019

    > Then my FW cannot run.

    What does it mean? Debug. Find out, what does it exactly do.

    JW

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