USBD data transmission stops while soft device is turned on

[masterLee]

Hi,

I have created a configuration based on usbd_app_uart example where both usbd and softdevice are enabled on my device as soon as the device is turned on. When I transmit a test string (Hello World) continuously with app_usbd_cdc_acm_write() function  to the serial terminal of my computer, data are sent  to the serial terminal and the serial com port is identified in the device manager of the computer for only 2 minutes or so.Then ,  suddenly the serial com port is disabled  and data are not sent to the serial monitor. 

Also during this time I have not connected my smartphone to the BLE of the nRF52840 DK that I am using for the tests. I just send data to the computer

When I remove the  BLE initialization functions(following code snippet), the usbd data transmision will work without stopping as expected.

ble_stack_init();
gap_params_init();
gatt_init();
services_init();
advertising_init();
conn_params_init();
advertising_start();

Furthermore, If I connect the usb cable to the nRF52840 DK and then I connect my smartphone to the BLE of the nRF52840, the com port will function without issues and without stopping.

I assume that the softdevice stops the LFCLK or HFCLK configuration  somehow and the usbd com port is disabled but this just an assumption...

Any ideas ?

Thank you for your time!

[Kenneth]

I suspect the advertisement is timing out, and you have the following code in on_adv_evt():

        case BLE_ADV_EVT_IDLE:
            sleep_mode_enter();
            break;

[masterLee]

Hi,

yes it was exactly that, Thank you!