Bulk IN Data transfer remains locked for a long time on windows and on os x

[iceseyes]

Hi,

 I'm experiencing this problem on Windows and OS X using  nRF52840 chips with SDK 15.3.

When I do a Bulk transfer from PC to Device I read immediately data from EPOUT1. I process it in my main loop and I send reply on EPIN1. In a cup of milliseconds I saw that transfer is completed, but 

nrf_drv_usbd_ep_is_busy(NRF_DRV_USBD_EPIN1)

return busy for very long time and PC remains blocked waiting for transfer completed

If I send a new message, device still result blocked

nrf_drv_usbd_ep_is_busy(NRF_DRV_USBD_EPOUT1)


and remains in this start until I kill the process on the pc and I send a new message.

On Linux it works great. On OS X it seems works, but more slowly than linux and on Windows problem is present.

I have noticed that on Linux and on Mac after I sent the reply to host two RESET event occured. on the other hand, on Windows this does not happen. 

Can you help me?

[Sigurd]

Hi,

What is the size of the packet you send from PC to the nRF52840?

What is the size of the reply from nRF52840 to the PC ?

Could you try to send a zero length packet when you want to finish the transaction? See this page.