52840 WDT causing confilict

[Avadacadabara]

Hi,

I added watchdog to usbd_ble_uart sample code.

BLE connection breaks when sending data to DK via USB.

What might be the cause?

Thanks.

[Kenneth]

I suggest to start by taking a look at the watchdog example:
https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.0.2/hardware_driver_wdt.html

I would have started at looking at the reload value you have set (NRFX_WDT_CONFIG_RELOAD_VALUE), and possible increase it. Secondly look at how often you are able to call nrf_drv_wdt_channel_feed(), and make sure it is called more frequently than set by the reload value (NRFX_WDT_CONFIG_RELOAD_VALUE).

Kenneth

[Avadacadabara]

Hi Kenneth,

Thanks for your advice.

The connection break seems not caused by watchdog reset. I feed the dog in main loop(which includes following commands only and I didn't receive LOG_INFO placed in WDT callback function).

nrf_drv_wdt_channel_feed(m_channel_id);
while (app_usbd_event_queue_process());
idle_state_handle();) and WDT reset tick is default 2 sec

When I send data with '\n' endline through USB, usb call back not triggered, I have to reopen the COM port to receive the data via ble_nus, the connection would break right after I receive it.

Another clue is that if I add NRF_LOG_INFO in front of nrf_drv_wdt_channel_feed();. The system response properly without connection lose. I tried to replace NRF_LOG_INFO  with delay yet it won't help.

I received GATT CONN TIMEOUT when disconnected(That's an Error 8).

Your help is appreciated!

[Kenneth]

This doesn't make much sense, and you can confirm that if you remove the watchdog all works again? 

Avadacadabara said:

I received GATT CONN TIMEOUT when disconnected(That's an Error 8).

The peer likely did a reset or out of range, causing a timeout.

Kenneth

[Avadacadabara]

Remove the watchdog, it works as usbd_ble_uart sample project.

Adding watchdog to usb-ble sample is an attempt to verify the reason of ble disconnection for another project. Somehow I solved the problem by switching slaves' pin ports...

But the problem still exists in this simplified project. I'll keep you updated.

Thanks.