MTU size

[Ridhi]

I want to know about following things:

1). NRF_SDH_BLE_GATT_MAX_MTU_SIZE

2). NRF_SDH_BLE_GAP_DATA_LENGTH

3).  NRF_SDH_BLE_GAP_EVENT_LENGTH

4). Connection event length extension

I have studied about ble_att_mtu code and https://www.novelbits.io/bluetooth-5-speed-maximum-throughput/

I want to know in simple manner what theses terms signify.

Eg: i have temperature humidity sensor SHT40 it gives 12 bytes of data  in one reading

Then i take about 100 readings like this on notification enable.

What does data length extension and above terms mean in this 

[Simonr]

Hi

1. NRF_SDH_BLE_GATT_MAX_MTU_SIZE is the static maximum MTU size set. This is well explained in this picture of LE data packet format and is the ATT Data here, it can be set to anything from 0 to 247 bytes, and will include 1 byte of OP code, 2 bytes of ATT handle, and up to 244 bytes of payload.

2. NRF_SDH_BLE_GAP_DATA_LENGTH is the requested BLE GAP data length that will be negotiated, and this can be set between 27 and 251 bytes. This is the MTU size + the L2CAP Header from the picture above.

3. NRF_SDH_BLE_GAP_EVENT_LENGTH is the time set aside for a specific connection on every connection interval in 1.25ms units. So if this equals to the connection interval, the entire connection interval is dedicated to 1 connection. This is set lower if you need to maintain multiple connections during each connection interval.

4. Connection event length extension: This option controls if the SoftDevice should attempt to extend the radio time for connections in a connection interval. This can positively affect throughput by making it possible to send more packets in a connection interval. This effect increases with the duration of the connection interval.

Best regards,

Simon