nRF Connect PC Not Receiving BLE Notification

[Tom]

I have an application running on an nRF52 with the S332 softdevice which is a server which exposes a a few services each with a few characteristics. I am using the Nordic SDK for the GATTS implementation. One of my services contains a characteristic which can 'notify' and another characteristic that can 'indicate'.

I have nRF Connect set up with a BLE dongle to act as the client.

On their own, my notify and indicate characteristics work fine. i.e. if I 'listen' only for indications from that one characteristic I receive all indications. Or if I 'listen' only for notifications from the other characteristic, I receive all notifications.

However, in the case where the app sends them in close succession I always miss the notify (never receive it).

Using nRF Connect on Android and iPhone it works fine - I get both the notification and indication even when they are sent close together.

As far as I can tell, I do not get any errors on my embedded server - it seems to think that the notification was sent successfully.

Any thoughts on what might be the cause or how to remedy this?

[Petter Myhre]

Strange. You are checking the error codes of sd_ble_gatts_hvx()? Do you also have a sniffer trace showing the behavior? Would it be possible for you to share a project that reproduces this behavior? What version of SDK and SoftDevice are you using? Which version of nRF Connect?

[Tom]

This is the output when I logged the error codes from the sd_ble_gatts_hvx call. I also log when I get the BLE_GATTS_EVT_HVN_TX_COMPLETE and BLE_GATTS_EVT_HVC calls.

 0> :ERROR:sd_ble_gatts_hvx err_code (notification): 0x00  
 0> :ERROR:sd_ble_gatts_hvx err_code (indication): 0x00  
 0> nrf_ble_gatt:ERROR:Event: BLE_GATTS_EVT_HVN_TX_COMPLETE Count:1  
 0> nrf_ble_gatt:ERROR:Event: BLE_GATTS_EVT_HVC

Is that what you would expect to see for doing a notification closely followed by an indication or does anything look like it is missing?

I am using Version 4.0.5 of the S332 Softdevice. Version of SDK is 13.0.0. nRF Connect v2.2.1.

[Petter Myhre]

sd_ble_gatts_hvx() returning 0x00, the BLE_GATTS_EVT_HVN_TX_COMPLETE event and the BLE_GATTS_EVT_HVC event are expected.

With this information I would expect a nRF Connect bug. Do you have a sniffer trace? Do you have a complete project so I can try to reproduce this?

[Tom]

I have an update. I guess i hadn't noticed before but I am getting both the notification and indication in the "Log" section at the bottom of nrfConnect but not in the main UI.

[Aaron]

Hi Petter,

I have the same issue on the nRF Connect PC version, but not on the Android version.