Can you do successive updates to a Notify Characteristic using sd_ble_gatts_hvs() during the same connection interval without losing data.

[SentinelLighting]

Can you do successive updates to a Notify Characteristic using sd_ble_gatts_hvs() during the same connection interval without losing data.

The question comes down to, does the Softdevice queue up multiple notify updates?

I am running S132 SoftDevice v6.1.0 as a peripheral

[Amanda Hsieh]

Hi Brian, 

SentinelLighting said:

HOW MANY ENTRIES CAN IT QUEUE?

It depends on the value of BLE_GATTS_HVN_TX_QUEUE_SIZE_DEFAULT.

The number of Handle Value Notifications that can be queued is configured by ble_gatts_conn_cfg_t::hvn_tx_queue_size When the queue is full, the function call will return NRF_ERROR_RESOURCES. A BLE_GATTS_EVT_HVN_TX_COMPLETE event will be issued as soon as the transmission of the notification is complete.

You might want to increase the size of the queue. As Runar indicated in how to set the queue size of notification, You don't need to change BLE_GATTS_HVN_TX_QUEUE_SIZE_DEFAULT or use sd_ble_cfg_set. The hvn_tx_queue_size will be indirectly configured based on NRF_SDH_BLE_GAP_DATA_LENGTH and NRF_SDH_BLE_GAP_EVENT_LENGTH values. You could increase the event length to 75 ms. This will increase the achievable throughput for the link.

-Amanda H.