BLE huge data transmission issue

[Chan_17]

Hello Nxp Team,

i am using Kw45 as central and peripheral and using example of temperature sensor and collector i,e normal att example. I tried to send data of 10,20,50 bytes from peripheral to central and i am able to receive that data  but whenever i try to increase data size like more than that i am facing connection issue. my requirement is to send 196 bytes data.and even i checked MTU size default it is 23 but i am using 247 bytes  still i am facing connection issue.

[luis_maravilla]

Hello,

The default size of 23 bytes is set to maintain a logical mapping between radio packets and ATT packets. In order to send more than 23 bytes of data, the data must be sent in smaller packets and multiple ATT request or if both devices (Like this scenario both KW45), peripheral and central can support increasing the ATT_MTU; make the change of value for gAttMaxMtu_c in both codes (Peripheral and central).

Also take in consideration that during the MTU exchange, both devices would send their maximum MTU to the other, and the minimum of the two is chosen as the new MTU.

This information is from Chapter 5.1.2 MTU exchange in Bluetooth Low Energy Application Developer’s Guide

Best Regards

Luis