BLE UART example doesn´t work

[Kampino]

Hello,

I want to use the BLE UART example on my PCA10040 development board, but I can´t transmit or receive any data from my PC to the smartphone with the nRF Connect app. The app prints out the message "UART started." and I can connect my smartphone with the device.

<info> app_timer: RTC: initialized.
<info> app: Debug logging for UART over RTT started.
<info> app: Connected
<info> app: Data len is set to 0xF4(244)

I tried to send some data to my device, but the device disconnects after a few seconds after selecting the RX (or any other) Characteristic.

[Edvin]

What does the log say when it disconnects?

BR,

Edvin

[Kampino]

Hello Edvin,

I get the following output:

<info> app_timer: RTC: initialized.
<info> app: Debug logging for UART over RTT started.
<info> app: Connected
<info> app: Data len is set to 0xF4(244)
<info> app: Disconnected

[Edvin]

Can you try to modify the line saying:

NRF_LOG_INFO("Disconnected");

To

NRF_LOG_INFO("Disconnected, reason 0x%02x", p_ble_evt->evt.gap_evt.params.disconnected.reason);

What does it say then?

Are you using bonding, or have you used the DK with an example that uses bonding? If so, can you please try to see if the DK is present in your phone's settings->bluetooth devices. If it is, try to "forget device".

BR,

Edvin

[Kampino]

Hello,

the example is working now. I think the reason was the available device in my Bluetooth settings on my phone.

[Edvin]

Ok. Then FYI, the issue was probably that the phone had stored bonding data (encryption keys) for the nRF device, and when the nRF failed to use those keys (because the example you are currently working on doesn't use bonding), the phone would disconnect because it looks like something is pretending to be your bonded device.

BR,

Edvin

[Kampino]

Hello Edvin,

thank you for the explanation. I will keep this in mind

Best wishes
Daniel