Intermediate
30 min

Fine-tune every aspect of your systems easily with ATmega328P

Fine-tune your world: Meet the precision of trimmer potentiometers

POT Click with Arduino UNO Rev3

Published Feb 14, 2024

Click board™

POT Click

Dev. board

Arduino UNO Rev3

Compiler

NECTO Studio

MCU

ATmega328P

We're dedicated to providing you with the tools to fine-tune and optimize your devices for better performance and accuracy, and our trimmer potentiometers are at the heart of this dedication

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Hardware Overview

How does it work?

POT Click is based on the MCP1501, a precision voltage reference IC from Microchip is used to provide the voltage of 2.048V. This voltage is routed to the small SMD jumper labeled as OUT SEL. By moving the jumper to the REF position, 2.048V will be applied to one end of the potentiometer. Otherwise, the potentiometer will be connected to the 3.3V rail of the mikroBUS™. The other end of the potentiometer is tied to GND, allowing to select voltage either from 0 to 2.048V range (VREF) or from 0 to 3.3V range. The adjustable voltage is available on both AN pin of the mikroBUS™ and 1x2-pin header on the upper edge of the Click board™, which is labeled as VOUT. The potentiometer itself is labeled as PT10MV11-103A2020-S. It is a high-quality potentiometer from Piher Sensing Systems. This company is otherwise known for their high-quality potentiometers, used in many industries. The

potentiometer has a carbon-based resistive surface with the resistance of 10 kΩ. It is a single-turn linear potentiometer, with 50% of resistance achieved when in the middle position. It has 10mm in diameter. Its turning knob is not fixed: the potentiometer has a hole with flat surfaces instead (hexagonal shape), and a small pole with the matching shape can be inserted. This makes possible using both fingers and some other precision tool (screwdriver, hex keys, and more). The output of the potentiometer is fed to the non-inverting input of the OPA344, a rail-to-rail single supply operational amplifier, from Texas Instruments. This operational amplifier is a perfect choice for this design, as it allows rail-to-rail operation, uses a single power supply of 5V, and has a stable unity gain. The OPA344 is used as a buffer, providing a constant input and output impedance. Without buffer, variable impedance

would affect the reference voltage. The reference voltage can provide less than 10 mA, with the significant voltage drop for output currents exceeding 2 mA. Therefore, the OPA344 ensures good stability of the circuit. The current output of this Click board™ is limited by the circuit at the output, which consists of two BJT transistors. When the output load is too large, a voltage drop will appear across the base-emitter resistor on the Q2 transistor, which in turn starts to conduct, reducing the voltage across the feedback loop, limiting the max current this way. Q1 transistor is otherwise used to provide enough current to the output load, preventing the damage to the buffer and the rest of the circuit. Therefore, in the case of short circuit, this transistor will start dissipating heat. It is dimensioned so that it can withstand short circuit on the output. The connected load can draw up to 100mA of current.

POT Click hardware overview image

Features overview

Development board

Arduino UNO is a versatile microcontroller board built around the ATmega328P chip. It offers extensive connectivity options for various projects, featuring 14 digital input/output pins, six of which are PWM-capable, along with six analog inputs. Its core components include a 16MHz ceramic resonator, a USB connection, a power jack, an

ICSP header, and a reset button, providing everything necessary to power and program the board. The Uno is ready to go, whether connected to a computer via USB or powered by an AC-to-DC adapter or battery. As the first USB Arduino board, it serves as the benchmark for the Arduino platform, with "Uno" symbolizing its status as the

first in a series. This name choice, meaning "one" in Italian, commemorates the launch of Arduino Software (IDE) 1.0. Initially introduced alongside version 1.0 of the Arduino Software (IDE), the Uno has since become the foundational model for subsequent Arduino releases, embodying the platform's evolution.

Arduino UNO Rev3 double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

AVR

MCU Memory (KB)

32

Silicon Vendor

Microchip

Pin count

28

RAM (Bytes)

2048

You complete me!

Accessories

Click Shield for Arduino UNO has two proprietary mikroBUS™ sockets, allowing all the Click board™ devices to be interfaced with the Arduino UNO board without effort. The Arduino Uno, a microcontroller board based on the ATmega328P, provides an affordable and flexible way for users to try out new concepts and build prototypes with the ATmega328P microcontroller from various combinations of performance, power consumption, and features. The Arduino Uno has 14 digital input/output pins (of which six can be used as PWM outputs), six analog inputs, a 16 MHz ceramic resonator (CSTCE16M0V53-R0), a USB connection, a power jack, an ICSP header, and reset button. Most of the ATmega328P microcontroller pins are brought to the IO pins on the left and right edge of the board, which are then connected to two existing mikroBUS™ sockets. This Click Shield also has several switches that perform functions such as selecting the logic levels of analog signals on mikroBUS™ sockets and selecting logic voltage levels of the mikroBUS™ sockets themselves. Besides, the user is offered the possibility of using any Click board™ with the help of existing bidirectional level-shifting voltage translators, regardless of whether the Click board™ operates at a 3.3V or 5V logic voltage level. Once you connect the Arduino UNO board with our Click Shield for Arduino UNO, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.

Click Shield for Arduino UNO accessories 1 image

Used MCU Pins

mikroBUS™ mapper

Analog Output
PC0
AN
NC
NC
RST
NC
NC
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
NC
NC
INT
NC
NC
TX
NC
NC
RX
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

POT Click Schematic schematic

Step by step

Project assembly

Click Shield for Arduino UNO front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Arduino UNO Rev3 as your development board.

Click Shield for Arduino UNO front image hardware assembly
Arduino UNO Rev3 front image hardware assembly
Charger 27 Click front image hardware assembly
Prog-cut hardware assembly
Charger 27 Click complete accessories setup image hardware assembly
Arduino UNO Rev3 Access MB 1 - upright/background hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
Necto image step 5 hardware assembly
Necto image step 6 hardware assembly
Arduino UNO MCU Step hardware assembly
Necto No Display image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Debug Image Necto Step hardware assembly

Track your results in real time

Application Output

1. Application Output - In Debug mode, the 'Application Output' window enables real-time data monitoring, offering direct insight into execution results. Ensure proper data display by configuring the environment correctly using the provided tutorial.

2. UART Terminal - Use the UART Terminal to monitor data transmission via a USB to UART converter, allowing direct communication between the Click board™ and your development system. Configure the baud rate and other serial settings according to your project's requirements to ensure proper functionality. For step-by-step setup instructions, refer to the provided tutorial.

3. Plot Output - The Plot feature offers a powerful way to visualize real-time sensor data, enabling trend analysis, debugging, and comparison of multiple data points. To set it up correctly, follow the provided tutorial, which includes a step-by-step example of using the Plot feature to display Click board™ readings. To use the Plot feature in your code, use the function: plot(*insert_graph_name*, variable_name);. This is a general format, and it is up to the user to replace 'insert_graph_name' with the actual graph name and 'variable_name' with the parameter to be displayed.

Software Support

Library Description

This library contains API for POT Click driver.

Key functions:

  • pot_read_an_pin_value - This function reads results of AD conversion of the AN pin

  • pot_read_an_pin_voltage - This function reads results of AD conversion of the AN pin and converts them to proportional voltage level

Open Source

Code example

The complete application code and a ready-to-use project are available through the NECTO Studio Package Manager for direct installation in the NECTO Studio. The application code can also be found on the MIKROE GitHub account.

/*!
 * \file 
 * \brief Pot Click example
 * 
 * # Description
 * Click board with the accurate selectable reference voltage output.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Performs logger and Click initialization.
 * 
 * ## Application Task  
 * Reads and displays on the USB UART the voltage level measured from AN pin.
 * 
 * \author Nemanja Medakovic
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "pot.h"

// ------------------------------------------------------------------ VARIABLES

static pot_t pot;
static log_t logger;

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    pot_cfg_t pot_cfg;  /**< Click config object. */

    /** 
     * Logger initialization.
     * Default baud rate: 115200
     * Default log level: LOG_LEVEL_DEBUG
     * @note If USB_UART_RX and USB_UART_TX 
     * are defined as HAL_PIN_NC, you will 
     * need to define them manually for log to work. 
     * See @b LOG_MAP_USB_UART macro definition for detailed explanation.
     */
    LOG_MAP_USB_UART( log_cfg );
    log_init( &logger, &log_cfg );
    log_info( &logger, " Application Init " );

    // Click initialization.
    pot_cfg_setup( &pot_cfg );
    POT_MAP_MIKROBUS( pot_cfg, MIKROBUS_1 );
    if ( ADC_ERROR == pot_init( &pot, &pot_cfg ) )
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void )
{
    float voltage = 0;
    if ( POT_OK == pot_read_an_pin_voltage ( &pot, &voltage ) ) 
    {
        log_printf( &logger, " AN Voltage : %.3f[V]\r\n\n", voltage );
        Delay_ms ( 1000 );
    }
}

int main ( void ) 
{
    /* Do not remove this line or clock might not be set correctly. */
    #ifdef PREINIT_SUPPORTED
    preinit();
    #endif
    
    application_init( );
    
    for ( ; ; ) 
    {
        application_task( );
    }

    return 0;
}

// ------------------------------------------------------------------------ END
/*!
 * \file 
 * \brief Pot Click example
 * 
 * # Description
 * Click board with the accurate selectable reference voltage output.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Performs logger and Click initialization.
 * 
 * ## Application Task  
 * Reads and displays on the USB UART the voltage level measured from AN pin.
 * 
 * \author Nemanja Medakovic
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "pot.h"

// ------------------------------------------------------------------ VARIABLES

static pot_t pot;
static log_t logger;

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    pot_cfg_t pot_cfg;  /**< Click config object. */

    /** 
     * Logger initialization.
     * Default baud rate: 115200
     * Default log level: LOG_LEVEL_DEBUG
     * @note If USB_UART_RX and USB_UART_TX 
     * are defined as HAL_PIN_NC, you will 
     * need to define them manually for log to work. 
     * See @b LOG_MAP_USB_UART macro definition for detailed explanation.
     */
    LOG_MAP_USB_UART( log_cfg );
    log_init( &logger, &log_cfg );
    log_info( &logger, " Application Init " );

    // Click initialization.
    pot_cfg_setup( &pot_cfg );
    POT_MAP_MIKROBUS( pot_cfg, MIKROBUS_1 );
    if ( ADC_ERROR == pot_init( &pot, &pot_cfg ) )
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void )
{
    float voltage = 0;
    if ( POT_OK == pot_read_an_pin_voltage ( &pot, &voltage ) ) 
    {
        log_printf( &logger, " AN Voltage : %.3f[V]\r\n\n", voltage );
        Delay_ms ( 1000 );
    }
}

int main ( void ) 
{
    /* Do not remove this line or clock might not be set correctly. */
    #ifdef PREINIT_SUPPORTED
    preinit();
    #endif
    
    application_init( );
    
    for ( ; ; ) 
    {
        application_task( );
    }

    return 0;
}

// ------------------------------------------------------------------------ END

Additional Support

Resources

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