nRF Connect (Desktop) reports 'Received a Gatt timeout'

[Remco Poelstra]

Hi,

I working on a BLE app with 2 custom services.

When I try to expand a characteristic I get a spinning indicator below the characteristic and after a while I get a 'Received a Gatt timeout'.

If instead I just try to write to a characteristic I immediately get a 'Characteristic value write failed: A gatt operation already in progress with device id xxxx.'

In my BLE event handler I only see the following events:

BLE Event: BLE_GAP_EVT_CONNECTED (0x0010).
BLE Event: BLE_GATTC_EVT_EXCHANGE_MTU_RSP (0x003A).
BLE Event: BLE_GAP_EVT_DATA_LENGTH_UPDATE_REQUEST (0x0023).
BLE Event: BLE_GAP_EVT_DATA_LENGTH_UPDATE (0x0024).
BLE Event: BLE_GATTS_EVT_SYS_ATTR_MISSING (0x0052).
BLE Event: BLE_GAP_EVT_CONN_PARAM_UPDATE (0x0012).

I do not see any events in the GATT event handler.

How do I find out what is going wrong? I'm totally lost here.

I'm using an nRF52840 with SDK 15.0.0.

Thanks in advance.

Kind regards,

Remco Poelstra

[Kenneth]

Can you try to set all the characteristics for the service in question to open (with no security required) and also allow read property? If that works then you know that you will have to try and fail a bit until you can identify which property is causing the problem.

Best regards,
Kenneth

[Remco Poelstra]

Hi,

For the write operation, which gives  'A gatt operation already in progress with device id xxxx.' Is there any way to find out what gatt operation is already in progress? The event handlers aren't called with anything that seems to stall and the nRF connect log also doesn't show which operation is in progress. Is there a way to find out which operation the message is referring to?

[Kenneth]

It's not possible to find which GATT operation is in progress without an sniffer log:

https://infocenter.nordicsemi.com/topic/ug_sniffer_ble/UG/sniffer_ble/intro.html

https://www.nordicsemi.com/Software-and-tools/Development-Tools/nRF-Sniffer-for-Bluetooth-LE/