Packets are fragmented to size less than the MTU

[EricC]

Hello, I am using the nRF52 with SDK 15 and this is subsequent to this post and I applied the change suggested in in nrf_ble_gatt.c and having the central exchange the MTU and the peripheral comes back with 247 which is good. However the device is generating fragmented packets per this screenshot:

I would like the packets to be generated in consolidated fashion as here (which was generated with a different central and without the change recommended previously):

I hope this makes sense and please let me know if there is more information I can provide.

thank you,

Eric

[haakonsh]

You need to enable Data Length Extension in addition to Extended MTU. The MTU packet is the packet used in the Link Layer <--> GATT layer communication and will be fragmented if the RF PHY packets are smaller than the MTU size. By enabling Data Length Extension the Link Layer will be able to send larger RF PHY packets to its peer. 

See devzone.nordicsemi.com/.../nrf52832-sdk12-1-extended-mtu-with-and-without-dle

[EricC]

Hi Haaakon, thank you (and forgive me if I have been contorting your name). I am using a 52840 DK with Zephyr software as a central and by making the config changes described here I have addressed the issue.

Eric