Hello TaTa_2447651 ,
The error "CY_BLE_ERROR_INVALID_PARAMETER" will occurs if 'param' is NULL, 'connHandle' is invalid or if 'param->handleValPair.value.len' value is greater than (Effective GATT MTU-3).
The amount of data that can be send/receive by the connected BLE devices depends on the negotiated MTU size. When you connect BLE device with the central device, negotiated GATT MTU = Min of (MTU of client device, MTU of server device).
Could you please check the negotiated MTU value during Exchange MTU procedure and update to the Length of the Value(i.e., param->handleValPair.value.len) to be packed for sending the data.
Hi P Yugandhar,
Thank you for your advice.
I noticed that there is a parameter in the "GATT Settings" tab of the BLE component configuration that changes the maximum MTU size.
I took some time to understand because for PSoC4 there was a parameter in the "L2CAP Settings" tab.
When the parameter was enlarged, data of 20 bytes or more can be sent by Notification.