NUS Message Confirmation

[awneil]

Does the Nordic UART Service (NUS) have a facility to confirm when a sent message has been received by the peer?

In particular, to confirm when an NUS message sent by a Central has been received by the Peripheral?

Or, conversely, an event to indicate when an NUS message sent by a Central has not been received by the Peripheral?

[MartinBL]

There is nothing like that in the NUS service implementation itself. However, if I understand you correctly you should be able to use the BLE_GATTC_EVT_WRITE_CMD_TX_COMPLETE event that is generated after a call to sd_ble_gattc_write(). Please refer to the Message Sequence Charts: GATTC Characteristic Value Write Without Response.

There is also an equivalent event generated after notifications are sent from the server side: GATTS Handle Value Notification.