Negociating MTU and modifying GAP event length while connected

[Sameh]

Hello,

I am working with nRF52832 , a soft based on the NUS service and SDK 15.2 ( S132) .

In the aim of reducing the current comsumption , I want to modify the throughput between a central NUS and a peripheral NUS without re-initializing BLE , just with modifying the MTU from 23 to 247 and the GAP event length from 6 to 400 , only when I need to send a huge amount of data, without losing connection.

• Is it possible that the peripheral changes its desired MTU while connected and sends to the central a request to re-negociate the MTU without losing the connection?

• And is it possible to modify the GAP event length without losing the connection between the central and the peripheral and without re-initializing BLE?

Thank you for your help.

Sincerely,

Sameh.

[haakonsh]

1. You can initiate a sd_ble_gattc_exchange_mtu_request, but there are some BLE stacks out there that do not expect a peripheral to initiate an MTU exchange request, and they might not be able to give you your wanted MTU size. In most use-cases, this is fine though. It will definitely not be a problem between two nordic devices.
2. Call sd_ble_gap_data_length_update.