How to send and receive more than 20 bytes (Default ATT_MTU_SIZE = 23-3) over ble using ST bluenrg LP?

[AMatt.2]

I am using BLE Scanner app to write data to a characteristic in BLE device. I sent 35 bytes of data, but the device receives data 20 bytes per write operation and then receives 15 bytes more. How to receive all the 35 bytes with single write operation.

I tried change BLE_INIT Parameters i.e changed MAX_ATT_MTU_CONF to 250, but it behaves the same way no change.

How can I achieve that?

[Winfred LU]

Please test with BLE_Throughput sample project in DK.

Please also reference PM0269 Bluetooth LE stack v3.x programming guidelines