BLE payload data length bigger than 20 bytes not registering any event.

RE: BLE payload data length bigger than 20 bytes not registering any event.

lara — Tue, 03 Dec 2024 11:03:33 GMT

can you tell explain the solution?

RE: BLE payload data length bigger than 20 bytes not registering any event.

ovrebekk — Thu, 30 Mar 2023 08:16:46 GMT

I am glad to hear you found the problem 🙂

The best of luck with your project!

Best regards
Torbjørn

RE: BLE payload data length bigger than 20 bytes not registering any event.

gamli — Wed, 29 Mar 2023 12:44:01 GMT

Hi Torbjørn,

Thanks for a quick response.

It was indeed something off with the setup of the characteristic I was using for this. It was set to 20 bytes - but really hidden in our code and setups for the characteristics. After some digging I managed to change this and now it works.

Cheers!

RE: BLE payload data length bigger than 20 bytes not registering any event.

ovrebekk — Tue, 28 Mar 2023 12:34:26 GMT

Hi Gamli

You mean to say that when the client is sending packets larger than 20 bytes they are not showing up on the server/peripheral side?

This sounds very odd, as long as the data length and MAX MTU is sufficiently large there should be no difference as seen from the Bluetooth stack.

You are sure that the characteristic in question is set up with a max length larger than 20 bytes?
Each characteristic can have a different max_len value, as set during the service and characteristic initialization.

Are you using a standard service provided in the SDK, or have you made your own?

Is the client using a regular write command to send the data?

Best regards
Torbjørn

RE: BLE payload data length bigger than 20 bytes not registering any event.

gamli — Mon, 27 Mar 2023 12:30:09 GMT

And to add to this, I did monitor the communication in Wireshark using a BLE sniffer with an nRF52840 dongle and did see that the packets were sent over the air, both a 20 bytes packet and when I increased the size to 22 bytes and larger. But as mentioned earlier, no interrupt was registered with the larger packets.