BLE SPP example magic numbers

[PeterR]

The BLE SPP server example sends up to "mtu-3" bytes using esp_ble_gatts_send_indicate().

Why mtu-3 and not the all the available mtu?

[chegewara]

Because 3 bytes are reserved for indication message OP code or something like that in lower layer driver. It can be found in bluetooth core specification if you really need it.

[PeterR]

Thanks.