Wireless Communication Library Support Forum

Frameworks => Bluetooth Framework => Topic started by: briandunham on May 05, 2022, 09:26:33 PM

Title: GATT Server - Characteristic Max Size
Post by: briandunham on May 05, 2022, 09:26:33 PM

Hello Mike,

I have a GATT client that is subscribed to a characteristic. That characteristic is configured in the GATT server to have a size of 255 bytes. But when my GATT client receives a OnCharacteristicChanged notification, the length is only 20 bytes. Is there a way to change this default MTU to a bigger size?

Title: Re: GATT Server - Characteristic Max Size
Post by: Mike Petrichenko on May 05, 2022, 09:50:56 PM

Unfortunately no, it is not possible on Windows platform. However if all is confugured correctly on a server side Windows always changes MTU size automaticaly to the server specified value. Also there can be dongle's limitation.

Title: Re: GATT Server - Characteristic Max Size
Post by: briandunham on May 10, 2022, 05:23:37 PM

Thank you for the clarification. I was able to find a "set_max_mtu" function in other API that we're using for the GATT server. Which allowed my WCL application in Windows to automatically adjust to the new MTU value.