BLE Disconnect NRF_ERROR_INVALID_STATE and NRF_ERROR_NOT_FOUND

[StevenW807]

Hi, I'm using nRF52805 and SEGGER. My BLE device disconnects with the mobile app occasionally. The disconnection happens randomly. In the debug mode, I see some messages. 

<error> app: ERROR 19 [NRF_ERROR_RESOURCES] at C:\xxxxxxxxxxxxxxx\main.c:2629
PC at: 0x0001ECF3
<error> app: End of error report

if( (err_code_ble_nus != NRF_ERROR_INVALID_STATE) && (err_code_ble_nus != NRF_ERROR_NOT_FOUND) ){
    APP_ERROR_CHECK(err_code_ble_nus);
}

Does anyone know the reason for the disconnection, and how to solve it, please? 

Thanks in advance

[ovrebekk]

Hi

The NRF_ERROR_RESOURCES error occurs when the internal packet buffers in the SoftDevice are full when you try to upload more data. 

This is an error you should expect in your application if you have a poor connection, or if you try to send a lot of data, so it is not recommended to run the APP_ERROR_CHECK() macro when this error occurs. I expect the disconnect happens because the APP_ERROR_CHECK() macro ends up resetting the nRF device. 

There are various older threads discussing how to handle this error properly, including this one:
https://devzone.nordicsemi.com/f/nordic-q-a/35125/how-to-deal-with-nrf_error_resources

Best regards
Torbjørn