An invalid value is acquired by Uart communication.

[Sawada]

Central info
   SDK: 15.3
   nRF52840

Uart communication is used.
In rare cases, the value obtained by checking the waveform with an oscilloscope was different from the value actually obtained with the app_uart_get () in the code.
Is there a similar case?

[Sawada]

Host CPU ----uart----> BLE

expect command: [10 02 00 06 00 01 00 00 10 03 04]

unexpect command: [10 02 02 06 00 00 01 00 00 10 03 04]

The expected command is received continuously every 100ms on BLE device.

The device may receive an unexpected command once every 10 minutes.

However, when I check with an oscilloscope, it is an expected command.

[haakonsh]

Can it be the result of the oscilloscope probe capacitively loading the data line? 

Can you show us the scope in question? 

Is the HFXO running when you're using the UART? 

[Sawada]

I'm sorry. Due to the actions we added on our own, an overrun occurred and invalid data was received.

[haakonsh]

Aww that sucks! I'm glad to hear you've located the root cause though :)