USB takes too long to start with SDK15.

[Murtaza]

Moving from SDK14 to SDK15, I noticed that USB takes long time to make connection (20 - 30 seconds). Comparing nrf_drv_usbd.c, I realized that the "shortcut between EP0DATADONE event and EP0STATUS task" was missing. I have added that in with //??????????? as a marker. It may help others who encounter similar problem.

nrf_drv_usbd.c

Regards

[Håkon Alseth]

Hi,

 

What nRF52840 chip are you testing with? Older revision devices may not work as expected, and we recommend that you always use the latest available silicon version.

 

Best regards,

Håkon

[Murtaza]

We are using the B Version. We can't get hold of production C version as yet. However, the issue will be the same on ALL versions.

Regards

[Håkon Alseth]

Hi,

 

Sorry, had to ask, as engineering A has many USB related issues and support for engineering A has been removed from SDK 15.

I believe you are seeing one of the changelog-items from v14.x -> v15:

http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v15.0.0/migration.html?cp=4_0_0_1_9_2#migration_usb

IN direction setup data handling
The driver no longer automatically acknowledges the IN direction setup transfer.

The shortcut set inside the driver when the last setup data IN transfer was prepared was removed. It means that now the higher layer must take care of calling nrf_drv_usbd_setup_clear for both directions of setup transfer.

Adding the SHORT back in would effectively revert this change.

 

Best regards,

Håkon