14-Bit ADC Usage Guide in Arduino UNO R4 Minima

Introduction
This guide is about
14-bit ADC Usage
in
Arduino UNO R4 Minima
Microcontroller Board.
The Arduino UNO R4 Minima is a versatile
microcontroller
board that offers a range of features for both beginners and experienced developers. One of its standout features is the
14-bit Analog-to-Digital Converter (ADC)
. ADCs are crucial components in many electronic systems, allowing for the conversion of
analog signals
(like those from sensors) into
digital values
that can be processed by microcontrollers.
Traditionally, the Arduino UNO boards come equipped with a
10-bit ADC
, which provides a resolution of
1024 discrete values
. However, the R4 Minima variant boasts a
14-bit ADC
, offering a significantly higher resolution of
16,384 discrete values
. This enhanced resolution allows for more
precise readings
and finer granularity, making it ideal for applications that require detailed and accurate analog signal measurements.
In this guide, we’ll show you how to use the
14-bit ADC
on the
Arduino UNO R4 Minima
. We’ll explain its benefits and give you some helpful tips. Plus, we’ll also discuss how to use

, and
14-bit ADCs
and talk about the smallest
voltage difference
they can detect.
Read this first
:
Arduino UNO R4 Minima Getting Started Guide
Recommended R4 Minima Kit
:
SunFounder Ultimate Kit
ADC Pins in Arduino UNO R4 Minima Board
The Arduino UNO R4 Minima Board, like its predecessors, comes equipped with multiple
Analog Input Pins
that can be used for
reading analog signals
. These pins are typically labeled as
A0
A1
A2
and so on.
The board usually has
6 analog input
pins (
A0 to A5
). These pins can
read signals
from
analog sensors
like temperature sensors, potentiometers, and light sensors.
Features of ADC in Arduino UNO R4 Minima Board
Enhanced Resolution
: Unlike the standard 10-bit ADC in most Arduino UNO boards, the R4 Minima variant boasts a
14-bit ADC
. This means it can represent the analog input value with more precision, offering
16,384
discrete values.
Variable Voltage Reference
: Users can choose between internal or
external voltage references
for the ADC, allowing for more flexibility in readings.
Increased Sampling Rate
: The ADC in the R4 Minima might offer a
faster sampling rate
, enabling quicker
analog signal readings
, which is crucial for real-time applications.
Noise Reduction Mode
: Some advanced ADC features include
noise reduction
capabilities, ensuring more accurate and less noisy readings.
Differential Mode
: This mode allows the ADC to measure the difference between two input pins, which can be useful in specific applications where the difference in signals is of interest.
Hardware Setup for ADC Usage
To use the ADC Pin, we will use a 10K potentiometer to supply voltages between 0V-5V to the A0 pin of Arduino Board. Here is a simple connection diagram.
Connection Steps:
Potentiometer Ground
: Connect one of the outer pins of the potentiometer to the Arduino’s GND pin.
Potentiometer Voltage
: Connect the other outer pin to the Arduino’s 5V pin.
Signal to A0
: Connect the potentiometer’s middle pin (wiper) to the A0 pin on the Arduino.
Ensure all connections are secure. Now, the potentiometer is ready to provide variable voltage to the A0 pin, which can be read by the Arduino’s ADC.
You can connect the potentiometer to the Arduino Board using the jumper wires on a breadboard.
Reading 10-Bit ADC Value & Voltage
Here is the basic code to read 10-Bit ADC Value and Voltage. In the code, the ADC resolution is set to 10 bits using the line:
analogReadResolution(10);
A 10-bit ADC means that the analog value can be represented using 1024 discrete values, ranging from 0 to 1023. When you read an analog input using the
analogRead()
function, it returns a value between 0 and 1023.
The voltage at the analog pin is calculated using the formula:
float voltage = (reading/1023.0)*5;
Use the
ADC Calculator
to calculate the ADC Value.
Copy this code and upload it to the Arduino UNO R4 Board.

int
analogpin
=
A0
;
void
setup
(
)
{
analogReadResolution
(

)
;
//change to 10-bit resolution
Serial
begin
(
9600
)
;
}
void
loop
(
)
{
int
reading
=
analogRead
(
analogpin
)
;
float
voltage
=
(
reading
/
1023.0
)
*

;
Serial
(
"Analog Value: "
)
;
Serial
println
(
reading
)
;
Serial
(
"Voltage: "
)
;
Serial
(
voltage

)
;
Serial
println
(
"V"
)
;
Serial
println
(
)
;
delay
(

)
;
}
Open the Serial Monitor to observe the ADC Value and Voltage.
At ADC Value of

, the voltage measured was
0.00489V
which is
4.89mV
. Therefore the minimum voltage that Arduino UNO R4 measures is 4.89mV.
At
2.5V
the the measured ADC Value is

At
5V
the the measured ADC Value is
1023
Reading 12-Bit ADC Value & Voltage
Here is the basic code to read 12-bit ADC Value and Voltage
In the code, the ADC resolution is set to 12 bits using the line:
analogReadResolution(12);
A 12-bit ADC means that the analog value can be represented using 4096 discrete values, ranging from 0 to 4095. When you read an analog input using the
analogRead()
function, it returns a value between 0 and 4095.
The voltage at the analog pin is calculated using the formula:
float voltage = (reading/4095.0)*5;
Copy this code and upload it to the Arduino UNO R4 Board.

int
analogpin
=
A0
;
void
setup
(
)
{
analogReadResolution
(

)
;
//change to 12-bit resolution
Serial
begin
(
9600
)
;
}
void
loop
(
)
{
int
reading
=
analogRead
(
analogpin
)
;
float
voltage
=
(
reading
/
4095.0
)
*

;
Serial
(
"Analog Value: "
)
;
Serial
println
(
reading
)
;
Serial
(
"Voltage: "
)
;
Serial
(
voltage

)
;
Serial
println
(
"V"
)
;
Serial
println
(
)
;
delay
(

)
;
}
Open the Serial Monitor to observe the ADC Value and Voltage.
At ADC Value of

, the voltage measured was
0.00122V
which is
1.22mV
. Therefore, the minimum voltage that Arduino UNO R4 measures is
1.22mV
At
2.5V
, the measured ADC Value is
2048
At
5V
, the measured ADC Value is
4095
Reading 14-Bit ADC Value & Voltage
Here is the basic code to read the
14-bit ADC Value
and Voltage. In the code, the ADC resolution is set to 14 bits using the line:
analogReadResolution(14);
A 14-bit ADC means that the analog value can be represented using
16,384 discrete values
, ranging from

to
16,383
. When you read an analog input using the
analogRead()
function, it returns a value between 0 and 16,383.
The voltage at the analog pin is calculated using the formula:
float voltage = (reading/16383.0)*5;
Copy this code and upload it to the Arduino UNO R4 Board.

int
analogpin
=
A0
;
void
setup
(
)
{
analogReadResolution
(

)
;
//change to 14-bit resolution
Serial
begin
(
9600
)
;
}
void
loop
(
)
{
int
reading
=
analogRead
(
analogpin
)
;
float
voltage
=
(
reading
/
16383.0
)
*

;
Serial
(
"Analog Value: "
)
;
Serial
println
(
reading
)
;
Serial
(
"Voltage: "
)
;
Serial
(
voltage

)
;
Serial
println
(
"V"
)
;
Serial
println
(
)
;
delay
(

)
;
}
Open the Serial Monitor to observe the ADC Value and Voltage.
At ADC Value of

, the voltage measured was
0.00031V
which is
0.31mV
. Therefore, the minimum voltage that Arduino UNO R4 measures is
0.31mV
At
2.5V
, the measured ADC Value is
8,192
At
5V
, the measured ADC Value is
16,383
Comparision Between 10, 12 & 14 Bit ADC of Arduino R4 Minima
Here’s a comparison table based on the provided data for 10-bit, 12-bit, and 14-bit ADC readings:
Feature/Specification
10-bit ADC
12-bit ADC
14-bit ADC
Max Discrete Values
1,024
4,096
16,384
Range of Values
0 to 1,023
0 to 4,095
0 to 16,383
Resolution (Min. Voltage)
4.89mV
1.22mV
0.31mV
ADC Value at 2.5V

2,048
8,192
ADC Value at 5V
1,023
4,095
16,383
This table now provides a concise comparison o