Best flow for notifications

RE: Best flow for notifications

run_ar — Fri, 15 Mar 2019 12:14:58 GMT

There is an example in the our SDK: nRF5_SDK_15.2.0_9412b96\examples\ble_central_and_peripheral\experimental\ble_app_att_mtu_throughput

Look at amts.c line:220. The while loop starts at line 249.

RE: Best flow for notifications

navarrocantero — Sun, 03 Mar 2019 16:44:54 GMT

Could I see the correct flow in one example ??

I still lossig data packets or if I do a ' do while ' with the sd_ble_gatts_hvx function I get repeated packets of data !

Wich advertisal time its better for this proposal , now its setted and 7,5 both, min and max

In the ble_hrs for example the hvx add data function its used on ble_hrs_heart_rate_measurement_send, and these function its called in the main.c file, inside the hrs_c_evt_handler function. And its used one time.

edit: solved with a delay, no data loss

do {
nrf_delay_ms(25);
err_code = sd_ble_gatts_hvx(p_cus->conn_handle, &hvx_params);
} while (err_code != NRF_SUCCESS);

But its slower.

RE: Best flow for notifications

run_ar — Thu, 28 Feb 2019 09:38:48 GMT

Hi,

For maximum throughput you need to check if there is tx buffers left. So call sd_ble_gatts_hvx and place data in the tx buffers until you get the error: NRF_ERROR_RESOURCES, When this happens you have to wait for a BLE_GATTS_EVT_HVN_TX_COMPLETE event and retry. If you do not check that you have succesfully placed data in the tx buffers you will lose data.

Message sequence chart here.

Notice that it might be possible to transfer data faster by using a longer connection interval and DLE. See SD documentation.