RE: Zephyr Bluetooth peripheral callbacks

DavidKaplan — Thu, 30 Jun 2022 12:59:22 GMT

Thanks

David

RE: Zephyr Bluetooth peripheral callbacks

Simon — Wed, 29 Jun 2022 15:57:36 GMT

I think you can achieve this by using the user data field of the bt_gatt_attr struct, it is the last input of BT_GATT_CHARACTERISTIC(). Then when you set up BT_UUID_AMI_LOG_TYPE_CHR you can point user data to X and when setting up BT_UUID_AMI_LOG_INTERVAL_CHR you can point it to Y. Then in the on_write callback, you can check if the user data (accessed through attr->user_data) is X (log type chr) or Y (interval chr) and then take the appropriate action.

The sample \zephyr\samples\bluetooth\peripheral\src\main.c is also using the user data field to achive this, with a slightly different approach, it simply points the user data to the array storing the char value and then simply writes the value to that field. Check it out yourself:

Setting up vnd "enc. characteristic" with user value=vnd_value and write function = write_vnd
- https://github.com/nrfconnect/sdk-zephyr/blob/v3.0.99-ncs1/samples/bluetooth/peripheral/src/main.c#L196
Setting up "vnd auth characteristic" with user value=vnd_auth_value and write function = write_vnd
- https://github.com/nrfconnect/sdk-zephyr/blob/v3.0.99-ncs1/samples/bluetooth/peripheral/src/main.c#L203
If write_vnd() function is triggered after a write to the "enc. characteristics", the following will happen
- Gets the user data, which will be vnd_value
  - https://github.com/nrfconnect/sdk-zephyr/blob/v3.0.99-ncs1/samples/bluetooth/peripheral/src/main.c#L62
- Writes the received value (buf) to vnd_value

Best regards,

Simon