Control Surface master
MIDI Control Surface library for Arduino


This is an example of the AnalogMultiplex class. It prints the states of all 16 switches connected to a multiplexers to the serial monitor.

AVR, AVR USB, Nano Every, Nano 33 IoT, Nano 33 BLE, Due, Teensy 3.x, ESP8266, ESP32


Optionally you can connect the enable pin as well, this is useful if you want to use multiple multiplexers with the same address lines and the same analog input. Otherwise, just connect the enable pin to ground.

If you are using a 3-bit multiplexer, like the CD74HC4051, you can uncomment the code specific to this multiplexer, and use only three address pins.

Connect a switch or push button between each input pin of the multiplexer and ground. A pull-up resistor is not necessary, because we'll use the internal one.


Open the serial monitor (CTRL+SHIFT+M) or the serial plotter (CTRL+SHIFT+L), and press some buttons, you should see all 16 signals printed or plotted.

Written by Pieter P, 2019-08-08

#include <Arduino_Helpers.h> // Include the Arduino Helpers library
// Instantiate a multiplexer
2, // input pin
{3, 4, 5, 6}, // Address pins S0, S1, S2, S3
// 7, // Optionally, specify the enable pin
// Alternatively, if you have a 3-bit mux:
// CD74HC4051 mux {
// 2,
// {3, 4, 5},
// // 7, // Optional
// };
void setup() {
mux.begin(); // Initialize multiplexer
mux.pinMode(0, INPUT_PULLUP); // Set the pin mode (setting it for one pin of
// the multiplexers sets it for all of them)
void loop() {
for (pin_t pin = 0; pin < mux.getLength(); ++pin) {
// A more fancy approach could be to use a range-based for loop
void loop2() {
for (pin_t pin : mux.pins()) {
// Okay, it's a bit slower, because it has to look up what ExtIO device the pin
// belongs to, but hey, it's nice to have it anyway
constexpr PinMode_t INPUT_PULLUP
Dummy header file for Arduino builder.
AnalogMultiplex< 4 > CD74HC4067
An alias for AnalogMultiplex<4> to use with CD74HC4067 analog multiplexers.
PinStatus_t digitalRead(pin_t pin)
An ExtIO version of the Arduino function.
uint16_t pin_t
The type for Arduino pins (and ExtendedIOElement pins).