Embrace the future of potentiometers with AD5206 and ATmega328P

Simplify voltage adjustments

Published Feb 14, 2024

Click board™

DIGI POT 8 Click

Dev. board

Arduino UNO Rev3

Compiler

NECTO Studio

MCU

ATmega328P

From audio equipment to industrial automation, our digital potentiometers offer an electronic means to finely tune parameters, enhancing overall system performance and accuracy

Hardware Overview

How does it work?

DIGI POT 8 Click is based on the AD5206, 6-channel 256-position digitally controlled device that performs the same electronic adjustment function as a potentiometer or variable resistor from Analog Devices. Each channel of the AD5206 contains a fixed resistor with a wiper contact that taps the fixed resistor value of 100kΩ at a point determined by a digital code loaded into the SPI-compatible serial-input register. The resistance between the wiper and either endpoint of the fixed resistor varies linearly concerning the digital code transferred into the variable resistor (VR) latch. The AD5206 also has an internal Power-On preset that places the wiper in a preset midscale condition at the Power-On state. The AD5206 communicates with MCU through the 3-wire

SPI serial interface with a maximum frequency 10MHz. Each VR has its VR latch that holds its programmed resistance value. These VR latches are updated from an internal serial-to-parallel shift register loaded from a standard 3-wire SPI serial-input digital interface. Eleven bits make up the data word clocked into the serial input register. The first three bits are decoded to determine which VR latch is loaded with the last eight bits of the data word when the CS pin of the SPI serial interface returns to a logic high state. In addition to the AD5206 present on the DIGI POT 8, this Click board™ has four 2x3 male headers. Three of them, under the labels A, W, and B, with the appropriate number, represent the corresponding DIGI POT terminal of the AD5206, while

the fourth header, with the label VCC and GND, represents an additional power supply output. Wiper terminal number 6, labeled as W6, also can be used as an auxiliary wiper output, routed to the AN pin of the mikroBUS ™ socket if the wiper back to the mikroBUS™ is required. This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. Also, it comes equipped with a library containing functions and an example code that can be used, as a reference, for further development.

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.

Microcontroller Overview

MCU Card / MCU

Architecture

AVR

MCU Memory (KB)

Silicon Vendor

Microchip

Pin count

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.

Used MCU Pins

mikroBUS™ mapper

Wiper Output

PC0

RST

SPI Chip Select

PB2

SPI Clock

PB5

SCK

MISO

SPI Data IN

PB3

MOSI

Power Supply

3.3V

Ground

GND

PWM

INT

SCL

SDA

Ground

GND

Take a closer look

Click board™ 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.

Arduino UNO Rev3 front image hardware assembly

Charger 27 Click front image hardware assembly

Charger 27 Click complete accessories setup image hardware assembly

Arduino UNO Rev3 Access MB 1 - upright/background hardware assembly

Necto No Display image step 8 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 DIGI POT 8 Click driver.

Key functions:

digipot8_write_data - DIGI POT 8 write data function
digipot8_set_wiper_1 - DIGI POT 8 set wiper 2 function
digipot8_set_wiper_2 - DIGI POT 8 set wiper 3 function

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 main.c
 * @brief DIGIPOT8 Click example
 *
 * # Description
 * This example demonstrates the use of DIGI POT 8 Click board.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and makes an initial log.
 *
 * ## Application Task
 * Iterates through the entire wiper range and sets all wipers to 
 * the iterator value each second. 
 * The current wiper position will be displayed on USB UART.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "digipot8.h"

static digipot8_t digipot8;
static log_t logger;

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    digipot8_cfg_t digipot8_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.

    digipot8_cfg_setup( &digipot8_cfg );
    DIGIPOT8_MAP_MIKROBUS( digipot8_cfg, MIKROBUS_1 );
    err_t init_flag  = digipot8_init( &digipot8, &digipot8_cfg );
    if ( init_flag == SPI_MASTER_ERROR ) 
    {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }

    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    for ( uint8_t cnt = DIGIPOT8_WIPER_POSITION_MIN; cnt < DIGIPOT8_WIPER_POSITION_MAX; cnt += 5 )
    {
        digipot8_set_wiper_1 ( &digipot8, cnt );
        digipot8_set_wiper_2 ( &digipot8, cnt );
        digipot8_set_wiper_3 ( &digipot8, cnt );
        digipot8_set_wiper_4 ( &digipot8, cnt );
        digipot8_set_wiper_5 ( &digipot8, cnt );
        digipot8_set_wiper_6 ( &digipot8, cnt );
        log_printf( &logger, " * All wipers position set to %d *\r\n", ( uint16_t ) cnt );
        
        Delay_ms( 1000 );
    }
}

void main ( void ) 
{
    application_init( );

    for ( ; ; ) 
    {
        application_task( );
    }
}

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