Question about indication charactristic

[alireza sadeghpour]

Hi to all,

I am new i ble tech, i read some where that notification charactristic dose not need acknowledgement but indication need, now i want know that this acknowledgement must be sent by ble stack or user application??

Thanks

[Sigurd]

Hi,

Indications require an explicit acknowledgment from the client in the form of a confirmation. A smartphone or a tablet is typically the client/central, while the nRF5 is the server/ peripheral.

If the nRF5 is the server, you will get an event BLE_GATTS_EVT_HVC when the client confirms. See this message sequence chart. After you get the confirmation/event, you can send another indication to the client. Again, it is the client that sends the acknowledgment, not the server.

If you are running the nRF5 in the client/central role, the nRF5 must do the confirmation. This must be done by the user application, by using the function sd_ble_gattc_hv_confirm(). See this message sequence chart.