Service Changed Characteristic example

RE: Service Changed Characteristic example

Sigurd — Wed, 22 May 2024 08:35:05 GMT

Hi!,

The Bluetooth Host in Zephyr does not expose a API for this, but handles it itself if it sees changes in the services.

As an experiment, you could try to expose the sc_indicate() function. Other users seems to have had success with that:

RE: Force GATT client to sync database with Zephyr

RE: Service Changed Characteristic example

QuentinD — Wed, 22 May 2024 07:11:38 GMT

[quote userid="15146" url="~/f/nordic-q-a/111240/service-changed-characteristic-example/485236"]You changed the name with bt_set_name(), or CONFIG_BT_DEVICE_NAME in prj.conf?[/quote]

Both: I put a value in CONFIG_BT_DEVICE_NAME to have a default value but if the user wants to change the device name, I call the bt_set_name() function.

[quote userid="15146" url="~/f/nordic-q-a/111240/service-changed-characteristic-example/485236"]A change to a characteristic value is not considered a modification of the service.[/quote]

Yes I know. The goal would be to use this service to refresh the cache of the IOS phone (I don't know if it works but as I saw on the internet that doing like that would solve my problem. So I would like to be able to do the test).

RE: Service Changed Characteristic example

Sigurd — Tue, 21 May 2024 22:26:08 GMT

[quote user="QuentinD"]Is there a function I need to call when I change the device name?[/quote]

You changed the name with bt_set_name(), or CONFIG_BT_DEVICE_NAME in prj.conf?

Note that the Service Changed Characteristic is used to indicate to connected devices that services have changed (i.e., added, removed or modified).
A change to a characteristic value is not considered a modification of the service.

RE: Service Changed Characteristic example

QuentinD — Tue, 21 May 2024 14:47:22 GMT

Is there a function I need to call when I change the device name?

RE: Service Changed Characteristic example

QuentinD — Thu, 16 May 2024 15:04:42 GMT

Yes CONFIG_BT_GATT_SERVICE_CHANGED=y

In the nrf_connect app, I set the Generic Attribute / Service Changed" to the value "Indications enabled". Then, I modify the "Device name" but I do not receive any notification telling me that there has been a modification of the Device name : do you know why ?

RE: Service Changed Characteristic example

Sigurd — Thu, 16 May 2024 12:28:38 GMT

Hi!

I'm not aware of any examples, but it should not be very complicated. Make sure that you have CONFIG_BT_GATT_SERVICE_CHANGED set to y