Within the Arduino IDE, select "Sketch" -> "Include Library ... I found for my ESP32 the big stress was converting the computed gain (dB) back to a 16 bit integer. This required computing pow10f(x/20) ...

This library provides several useful extensions that make programming Arduino / mbed for non-trivial apps simpler ... syncing and then reading pins. int valueRead = ioDeviceDigitalReadS(ioExpander, 0) ...