If it's serial, indeed one way. You normally need only a voltage divider on the Arduino TX line, as the 3.3V of the slave TX is enough for the RX of Arduino to recognise it as a high.
If it's serial, indeed one way. You normally need only a voltage divider on the Arduino TX line, as the 3.3V of the slave TX is enough for the RX of Arduino to recognise it as a high.