How to develop a GATT Client application?

RE: How to develop a GATT Client application?

Carles — Mon, 19 Aug 2013 06:51:09 GMT

Hi Joe,

You will need to enable notifications and/or indications by writing to the remote device's Client Characteristic Configuration Descriptor (CCCD) for the relevant Characteristic, setting a "1" in the relevant bits.

Before that of course, you will have to discover the service, characteristic and descriptors that are of interest to you, so the procedure would be a sequence of the following in the Message Sequence Chart procedures:

GATTC Primary Service Discovery GATTC Characteristic Discovery GATTC Descriptor Discovery GATTC Characteristic or Descriptor Value Write

You can find example code in the SDK that implements this is ble_ans_c.c (see function cccd_configure() )

Hope that helps.

Regards,

Carles

RE: How to develop a GATT Client application?

Yalcin Akdogan — Sat, 17 Aug 2013 08:50:50 GMT

Hi,

Thanks for clear response. One further question for same use case.

How can you subscribe to GATT Servers discovered characteristic with "Indicate" or "Notify" ?

I saw the Message Sequence Charts "GATTC Handle Value Indication" and "Notification", but missing the part how to enable GATT Server to send this values. I could not see any GATTC function to do it.

Best Regards.

RE: How to develop a GATT Client application?

Carles — Thu, 15 Aug 2013 07:30:36 GMT

Hi there,

128bit- primary serivice UUID ,its characteristics' UUIDs(128bit) are all known, how to discovery the service and characteristics in nrf51822 peripheral?

You need to do this in 2 steps with the S110:

Use sd_ble_uuid_vs_add() to add all the 128-bit UUIDs that your central uses
Use the GATTC functions to discovery your services characteristics, for example:

sd_ble_gattc_primary_services_discover() sd_ble_gattc_characteristics_discover()

While using the UUIDs that you previously added.

Regards,

Carles

RE: How to develop a GATT Client application?

Bastiaan — Thu, 15 Aug 2013 04:38:05 GMT

i must implement it as ble_ans_c.c

RE: How to develop a GATT Client application?

Guest — Thu, 15 Aug 2013 04:38:05 GMT

i must implement it as ble_ans_c.c

RE: How to develop a GATT Client application?

Guest — Thu, 15 Aug 2013 04:12:59 GMT

the application should be like Alert Notification Service Client. but in my situation, the Service in the central device end just expose UUIDs and permissions(write or notify).

RE: How to develop a GATT Client application?

Bastiaan — Thu, 15 Aug 2013 04:12:59 GMT

the application should be like Alert Notification Service Client. but in my situation, the Service in the central device end just expose UUIDs and permissions(write or notify).