nRF5 SDK or nRF Connect SDK Bare Metal - can I configure GATT server without client role?

[Matthew K]

Hi everyone. When configuring the GATT role, there are GATT server role, GATT client role and both. When using nRF5 SDK or nRF Connect SDK Bare Metal, is it possible to configure the nRF52840 as a GATT server role only, without a GATT client role? Thank you!

[Vidar Berg]

Hi,

The Bluetooth stack (softdevice) supports supports both server and client functions (Ref. GATT Client functions, GATT Server functions) and what role is used is dependent on what function the application uses. The s115 Softdevice supports the GAP peripheral and Broadcaster role. Softdevice s145 which is coming later will also include support for the GAP observer and central role.

Best regards,

Vidar

[Matthew K]

Hi Vidar. Using nRF5_SDK_17\ble_peripheral\ble_app_uart\pca10056\s113 as an example,

NRF_BLE_GATT_DEF(m_gatt);
gatt_init() - nrf_ble_gatt_init()

Does this example enable both the GATT server and client roles, so that the nRF52 can get the Service Change Indication?

[Vidar Berg]

Hi,

Could you please say a bit more about what you are trying to achieve? The sample does not subscribe to the service changed indication, and it would not make sense for it to do so as it doesn't do any GATT client operations. 

[Matthew K]

Hi Vidar. Using these screenshots and the Android Nordic Connect BLE app,

let's talk about the Android's GATT server configuration.

Suppose I made these changes. When using nRF5_SDK_17\ble_peripheral\ble_app_uart\pca10056\s113

will the nRF52 get a Service Change Indication event?

[Vidar Berg]

Hello,

Your application will first need to be subscribed to the Service changed indication event. You can use the ble_app_ancs_c example as a reference for this.

Best regards,

Vidar

[Matthew K]

Hi Vidar. Yes, subscribing is one thing. My main questions are

Can SoftDevice S113 (Peripheral-only Bluetooth Low Energy protocol stack) examples subscribe to the Service changed indication event?

If this is true, although the nRF52 is a GAP peripheral, can the nRF52 be a GATT server and client?

[Vidar Berg]

Yes, all the softdevices support GATT Client and Server functions.

[Matthew K]

Hi Vidar. Then my question is, using either the

nRF5 SDK v17 or nRF Connect SDK Bare Metal,

how can I disable / not initialize GATT client functions from the user firmware?

Is this possible?