52833 esb+usbd use together issue

[summer]

I use SDK17.10, when I send radio data using the esb，At this time, insert the usb, it takes a long time to enumerate the usb successfully;  when I disable the esb,I plugged in the usb and soon the enumeration was successful.I wonder what causes USB enumeration to be slow?  I used nrf52833DK board to do the experiment

[ovrebekk]

Hi 

Approximately how many packets are you sending through ESB every second, and how large is the payload? 

For every packet sent there will be some interrupts firing and some code that has to be run in order to handle packet buffering etc, and this will take away CPU cycles that could otherwise have been used by the USB stack.

You are making sure to call app_usbd_event_queue_process() repeatedly from the main loop, even when ESB is running?

Best regards
Torbjørn

[summer]

• Hello, thank you very much. I've taken care of it

[ovrebekk]

Hi 

Good to hear!

Do you mind sharing what the problem was? 

Best regards
Torbjørn

[summer]

hi,The sleep(nrf_pwr_mgmt_run())  function cannot be used when working in USB

[ovrebekk]

Hi

Interesting. It should be possible to enter sleep, even when using USB. The critical thing is that you make sure to run app_usbd_event_queue_process() as long as it returns true, before you can go to sleep. 

The snippet below is from one of the USB examples in the SDK:

    while (true)
    {
        while (app_usbd_event_queue_process())
        {
            /* Nothing to do */
        }
        
        if(m_send_flag)
        {
            static int  frame_counter;

            size_t size = sprintf(m_tx_buffer, "Hello USB CDC FA demo: %u\r\n", frame_counter);

            ret = app_usbd_cdc_acm_write(&m_app_cdc_acm, m_tx_buffer, size);
            if (ret == NRF_SUCCESS)
            {
                ++frame_counter;
            }
        }
        

        UNUSED_RETURN_VALUE(NRF_LOG_PROCESS());
        /* Sleep CPU only if there was no interrupt since last loop processing */
        __WFE();
    }

Best regards
Torbjørn

[summer]

hi,thank you very much,l got it.