Set the advertising interval in units of 0.625 ms. Defaults to 100ms (160 * 0.625 ms) if not provided.
BLE.setAdvertisingInterval(advertisingInterval)
Nothing.
// begin initialization
if (!BLE.begin()) {
Serial.println("starting Bluetooth® Low Energy module failed!");
while (1);
}
// ...
BLE.setAdvertisingInterval(320); // 200 * 0.625 ms
BLE.advertise();