Notify and Indication length

[EmanuelePozziNordic]

Hello,

In past I worked with BLE 4.0 and I remember that using the notify we have a max amount of  data of 20 bytes.

Now we are working with BLE 4.2, does we have this limitation also in BLE 4.2?

In BLE 4.2 which is the maximum amount of byte for Notification and Indication?

Thanks

Best regards

Emanuele

[Marjeris Romero]

Hi,

With BLE 4.1 the ATT MTU is 23 bytes, but with BLE 4.2 it can be increased up to 247 bytes. Both notification and indication packet will have a 3-bytes header including the OP-code (operation, 1 byte) and the attribute handle (2 bytes) so the attribute length for notification or indication can be max ATT_MTU - 3 bytes =  244 bytes in BLE 4.2.

Cheers,

Marjeris

[EmanuelePozziNordic]

Hello,

Great! Thanks.

I ask you another information.

Is a Nordic dongle that support BLE 4.2 available ?

Thanks

Best regards

Emanuele

[Marjeris Romero]

Hi,

Yes! Both the nRF52840 dongle  and the nRF51 dongle support BLE 4.2. The nRF51 dongle needs to be used in combination with softdevice s130 for BLE 4.2 support.

Best Regards,

Marjeris