USBD connect/disconnect

[Mo]

Hi,

Is it possible to fool the system (via software) to perform a USB connect/disconnect as if it was physically connected and disconnected?

[Andre]

Look at the nrf_usbd_pullup_disable  and nrf_usbd_pullup_enable  functions. If you disable the pull-up, the host will see this as a disconnect. 

[Mo]

Thanks for your reply, however, it does not seem to do the trick.

There seems to be an issue with the USBD as follows:

   - Create a file

   - Modify it (write some date to it)

   - Connect the USB

   - I am able to see the file on the USB drive

   - Disconnect the USB

   * at this point everything is file as fatfs_init() works fine and I can log more data to the file

  However:

   - Connect the USB

   - Copy (Drag/Drop) the file from the USB drive

   - Disconnect the USB

   - fatfs_init() fails and I no longer can access the file; unless I physically connect/disconnect the USB again.

My intention is in failed times to mimic a USB connect/disconnect without the user's knowledge.

   

[Andre]

The pullup enable/disable should disconnect the device from the PC's perspective. Can you verify this happens?
I suppose on the microcontroller, you'll need to manually generate a disconnect event after disabling the pullup. 

[Mo]

I ended up using this suggestion and it solved the issue. Thanks.

Hi.

I had the almost the same issue. After any access to the files via the USB, the file system was demolished after internal flash access.
I added additional logs to the SDK in QSPI module and it has shown me, that QSPI uninit function (block_dev_qspi_uninit), called after unplugging the USB, was busy (return with NRF_ERROR_BUSY).

I add this code at the beggining of block_dev_qspi_uninit:

if ((p_work->state != NRF_BLOCK_DEV_QSPI_STATE_IDLE))

{

 wait_for_idle(p_qspi_dev);

}

It fixed the problem.

Best regards
Artur