Arduino Digital Potentiometer X9C103S Interfacing Examples

This is a comprehensive guide for Arduino Digital Potentiometer X9C103s Module Interfacing. You’ll learn how to use X9C103s With Arduino To Create Some Digital Potentiometer Applications to practice what we’ll be learning in this tutorial.

We’ll start by explaining how the X9C103s digital potentiometer module works, its pinout, and how to connect it With Arduino. Then, we’ll install the Arduino X9C10x Library, and create a couple of Arduino digital potentiometer example projects with the X9C103s module. Without further ado, let’s get right into it!

Arduino Digital Potentiometer (X9C103s)
Arduino X9C103s Digital Pot Interfacing
Arduino Digital Pot X9C10x Library Installation
Arduino Digital Potentiometer X9C103s Example
Arduino X9C103s TTL Oscillator Example
Arduino Digital Potentiometer X9C10x Projects’ Tips
Wrap Up

Arduino Digital Potentiometer (X9C103s)

The X9C103s is a digital potentiometer IC that consists of an array of resistors, wiper switches, control logic, and NVM memory to store the wiper position. By enabling and disabling the internal fixed resistors, it can act as a variable resistor with 100 steps. The X9C103s potentiometer is a 10kΩ resistor with a step size of 100Ω per wiper position tick.

For this tutorial, we’ll use the X9C103s module with Arduino to change the potentiometer’s wiper position programmatically and use that to generate a variable voltage divider network and also to replace a resistor in an RC oscillator circuit to obtain a programmable variable frequency oscillator circuit.

X9C103s Module Digital Potentiometer 10k

Buy an X9C103s Module: you can find it here on Amazon.com

X9C103s Tech Specs

Operating Voltage	5v
Total Resistance	10kΩ (±20% tolerance)
Wiper Positions	100
Minimum Resistance	40Ω
Maximum Wiper Current	4.5mA

Arduino Digital Potentiometer Applications

Digital Potentiometers are required in various types of sensing, actuation, tunable filters, and oscillator applications. Here are some applications where you might consider using a digital potentiometer like the X9C103s:

Volume Control
Light Control
Auto-Tunable Filters
Auto-Contrast Adjustment
Programmable Oscillators

You can find more information about the X9C10x digital potentiometer IC family in its Datasheet from Renesas.

Arduino X9C103s Digital Pot Interfacing

Now, let’s move to interfacing the X9C103s digital potentiometer with Arduino. Let’s check the pinout, pin functions, and the wiring diagram.

X9C103s Pinout

V_CC is the module’s power supply input pin (connects to +5v).

CS is the chip select (Enable) pin.

INC is the increment signal input pin.

U/D is the Up/Down wiper increment direction control pin.

GND is the ground pin.

H is the High end terminal of the digital potentiometer.

W is the wiper middle pin of the potentiometer.

L is the Low end terminal of the digital potentiometer.

Wiring X9C103s With Arduino

Here is the wiring diagram for the X9C103s digital potentiometer with Arduino that we’ll be using in the example projects hereafter in this tutorial.

Arduino Digital Potentiometer X9C103S Wiring Diagram

Arduino Digital Pot X9C10x Library Installation

You can download and install the Arduino X9C10x digital potentiometer library manually from GitHub, or alternatively, install it within the Arduino IDE itself. Just open the library manager. Tools > Manage Libraries > Search for X9C. Then, click Install and let it finish the installation.

Arduino X9C103S Digital Potentiometer Library Code Example

Now, you can easily use the Arduino Digital Potentiometer X9C10x library and check the built-in examples for the library to help you get started.

We’ll move now to the practical code example to test the Arduino Digital Potentiometer X9C103s Module interfacing.

Arduino Digital Potentiometer X9C103s Example

Now, we’re ready to create our first Arduino X9C103s Digital Potentiometer demo application. In which, we’ll hook up the digital potentiometer to Vdd and GND to create a voltage divider network. The output of the wiper pin voltage will be measured by the Arduino’s A0 analog input pin. The core logic of this application, will gradually increment the wiper position up to the maximum and gradually decrease it down to the minimum and keep repeating that forever.

To visualize the output signal, we’ll feed it back to our Arduino’s A0 analog input channel and send the readings over the serial port to the PC where we’ll view the signal on the serial plotter.

Wiring

The wiring diagram for this example project is shown in the previous section, scroll up and check it out. Below is an image of how the whole setup looks like at the end, ready for the test.

Example Code

Here is the full code listing for this example.

* LAB Name: Arduino X9C103S Digital Potentiometer Demo Example

* Author: Khaled Magdy

* For More Info Visit: www.DeepBlueMbedded.com

#include <DigiPotX9Cxxx.h>

DigiPot MyPot(2,3,4); // Pins:(INC, U/D, CS)

void setup() {

Serial.begin(9600);

}

void loop() {

for(int i=0; i<100; i++)

{

MyPot.increase(1);

Serial.println(analogRead(A0));

delay(10);

}

for(int i=0; i<100; i++)

{

MyPot.decrease(1);

Serial.println(analogRead(A0));

delay(10);

}

Code Explanation

First of all, we need to include the Arduino DigiPotX9Cxxx.h library to use the digital potentiometer X9C103s module.

1	#include <DigiPotX9Cxxx.h>

Then, we’ll create an instance of the DigiPot class for our digital potentiometer module and assign the control signal pins to it.

1	DigiPot MyPot(2,3,4); // Pins:(INC, U/D, CS)

setup()

in the setup() function, we’ll initialize the serial port to send the measured signal back to the PC for display on the serial plotter.

1	Serial.begin(9600);

loop()

In the loop() function, we’ll create two for loops. In the first loop, we’ll increment the potentiometer wiper position all the way up to the maximum position. In the second loop, we’ll decrease the wiper position all the way down to the minimum value. In each of them, we’ll print the voltage output that we fed back to the A0 analog input channel over the serial port, and keep repeating.

void loop() {

for(int i=0; i<100; i++)

{

MyPot.increase(1);

Serial.println(analogRead(A0));

delay(10);

}

for(int i=0; i<100; i++)

{

MyPot.decrease(1);

Serial.println(analogRead(A0));

delay(10);

}

Testing Result

Arduino-X9C103s-Digital-Potentiometer-Library-Code-Example-Test

The output is exactly what we expect it to be. The output voltage is gradually going up from 0v to 5v and down to 0v again which means we’re successfully controlling the digital potentiometer’s wiper position.

Arduino X9C103s TTL Oscillator Example

In this second example project, we’ll use the X9C103s digital potentiometer with Arduino and a CD40106 Schmitt-Trigger Hex-Inverter chip to create a TTL RC oscillator with controllable output clock frequency. We’ll replace the resistor in the TTL RC oscillator circuit with the digital potentiometer to act as a variable resistance to change the output frequency according to the current value of the digitally controlled resistor.

The Arduino board will read two input push buttons to increase/decrease the resistor’s value and consequently change the output frequency of the TTL inverter RC oscillator.

TTL Schmitt-Trigger Inverter Oscillator Circuit & Equations

Below is a figure showing a typical application circuit for the CD40106 Schmitt-Trigger Inverter Oscillator as found in its Datasheet. It only requires one resistor and one capacitor to operate. The output Frequency = 1 / t_A

Note that: V_DD = 5v, V_P = 3v (in the datasheet), and V_N = 2v (in the datasheet).

In this example project, I’ll use a 100nF capacitor and the X9C103s as a variable (10kΩ) resistor. Therefore, the output signal’s frequency for this oscillator circuit will fall in the following range. (by substituting all known values in the t_A equation and calculating F = 1/t_A)

X9C103s Min Resistance value = 40Ω. At which the output frequency F_OUT(Max) = 1/(40 x 100 x 10^-9 x ln[(1.5)(1.5)]) = 300kHz

X9C103s Max Resistance value = 10kΩ. At which the output frequency F_OUT(Min) = 1/(10,000 x 100 x 10^-9 x ln[(1.5)(1.5)]) = 1.2kHz

F_OUT range is (1.2kHz – 300kHz).