How to detect service change of ANCS gatt server

RE: How to detect service change of ANCS gatt server

Joseph — Wed, 20 May 2015 07:55:37 GMT

Noted with thanks!

RE: How to detect service change of ANCS gatt server

Hung Bui — Wed, 20 May 2015 07:43:24 GMT

@Joseph: There could be some diference in the API but the principle should be the same. I think you should be able to use the library with some minor modification.

You can also have a look at ble_app_alert_notification example in SDK v5.1.0, the ble_ans_c.c library handles the service discovery and enables CCCD.

RE: How to detect service change of ANCS gatt server

Joseph — Tue, 19 May 2015 08:14:05 GMT

Hello Hung, unfortunately, my work is based on SDK 5.1.0 and s310 v1.0.0, can I use the ble_db_discovery.c library by direct copying from newer SDK? And which SDK I should use? Thanks!

RE: How to detect service change of ANCS gatt server

Hung Bui — Tue, 19 May 2015 07:54:32 GMT

@Joseph: You are correct, service discovery process starts by calling sd_ble_gattc_primary_services_discover(), you will have BLE_GATTC_EVT_PRIM_SRVC_DISC_RSP event call back. You can use the ble_db_discovery.c library which handle the service discovery for you. You can have a look at the ble_app_hrs_c example for S120 (ble_central) where we do service discovery then enable CCCD for battery and hrs services.

RE: How to detect service change of ANCS gatt server

Joseph — Mon, 18 May 2015 03:10:25 GMT

Hello Hung, thank you for your suggestions. If we want to subscribe to the service changed indication, the first step is to use the function sd_ble_gattc_primary_services_discover() to search for the Generic Attribute (0x1801), is that correct? Thanks!

RE: How to detect service change of ANCS gatt server

Hung Bui — Fri, 15 May 2015 09:17:35 GMT

@Joseph: I'm sorry for misleading you. The spec tells the NC "should" not "shall" so it's optional. I edited my answer.

In our example, unfortunatelly, we don't subsrcribe to service changed indication but to a service discovery every time we get connected. If we don't see the ANCS service we will disconnect.

I guess this something you would need to implement on your own, to enable service change CCCD, and wait for the indication event to do either a disconnect and reconnect, or another service discovery. Another option is to add a timer and do service discovery to look for ANCS to be available for several time, and disconnect after a timeout.

RE: How to detect service change of ANCS gatt server

Joseph — Thu, 14 May 2015 08:22:49 GMT

Hello Hung, I downloaded the ble_app_ancs project (SDK v8.1.0), I search through the 2 files main.c & ble_ancs_c.c with the matching word "change", but I cannot find anything related to service change of the gatt server, could you give me some hints? Thanks!

RE: How to detect service change of ANCS gatt server

Hung Bui — Wed, 13 May 2015 12:26:10 GMT

@Joseph: There is ble_app_ancs project in the nRF51SDK v8.1.0 that you can have a look at.

RE: How to detect service change of ANCS gatt server

Joseph — Wed, 13 May 2015 12:03:24 GMT

Thank you for your reply! Is there a sample project that I could look at for reference?

RE: How to detect service change of ANCS gatt server

Hung Bui — Wed, 13 May 2015 11:33:31 GMT

@Joseph: According to the spec of ANCS " the NC (notification consumer) should look for and subscribe to the Service Changed characteristic of the GATT service in order to monitor for the potential publishing and unpublishing of the ANCS at any time."

What it means is the client should enable indication on the service changed characteristic. And it will receive an indication (BLE_GATTC_EVT_HVX event) when there's a service change.

[EDIT] changed from "need to" to "should"