RE: A few questions about GATT

Sigurd — Tue, 20 Dec 2016 10:32:42 GMT

Hi,

1) The GATT table is a part of the SoftDevice, and the application can use the API functions sd_ble_gatts_* to interact with the GATT. You can find the GATT SoftDevice functions here.

2) Yes, there are always 2 mandatory services:

The Generic Access service with UUID 0x1800, which contains general information about the device.
The Generic Attribute service with UUID 0x1801, used to notify the central of changes in the services and characteristics on the peripheral.

3) If you want to read/write to a characteristics you need to add read/write properties and permissions to the characteristics. You can find more information in e.g. the BLE Characteristics tutorial.