Intermediate
30 min

Shape your signals with AD9834 and ATmega328

Frequency stimulus/waveform generation

Waveform 2 Click with Arduino UNO Rev3

Published Feb 14, 2024

Click board™

Waveform 2 Click

Dev Board

Arduino UNO Rev3

Compiler

NECTO Studio

MCU

ATmega328

Achieve sine and triangular outputs alongside frequency phase tuning and modulation with an advanced waveform generator

A

A

Hardware Overview

How does it work?

Waveform 2 Click is based on the AD9834, a 75 MHz low-power DDS device capable of producing high-performance sine/triangle/square outputs from Analog Devices. The AD9834 can have a broad range of simple and complex modulation schemes. These modulation schemes are fully implemented in the digital domain, allowing the accurate realization of complex modulation algorithms using DSP techniques. It contains a 16-bit control register accessible through the SPI serial interface that sets up the AD9834 as the user wants to operate it. The internal circuitry of the AD9834 consists of a numerically controlled oscillator (NCO), frequency and phase modulators, SIN ROM, a DAC, a comparator, and a regulator. The outputs of the AD9834 are filtered by an RC network and then amplified via THS4551, a differential amplifier that offers an easy interface from single-ended sources to the differential output required by high-precision

analog-to-digital converters from Texas Instruments.The output signal from the AD9834 follows two paths. One path is routed to an output connector labeled as Signal Out when the output waveform of the generator is sinusoidal or triangular, while the other path, routed to an output connector labeled as Square Out, is used when the output waveform of the generator is square. In addition to the positive supply voltage requirement, the THS4551 amplifier also has a negative supply voltage, achieved by the ADM8829, a charge-pump voltage inverter used to generate a negative supply from a positive input from Analog Devices. This Click board™ also has an external oscillator of 75MHz, enabled by the EN pin of the mikroBUS™ socket, and represents the maximum frequency that the AD9834 can accept. The 75MHz clock produces the cleanest possible Sine waveform at high frequencies, while the low frequencies create

errors. In addition to these features, the Waveform 2 Click also has an EEPROM memory IC the 24AA64, an i2C configurable 64K serial EEPROM from Microchip that can be used for various storage applications. The Waveform 2 Click communicates with MCU using the 3-Wire SPI serial interface compatible with standard SPI, QSPI™, and MICROWIRE™ and operates at clock rates up to 40 MHz. Besides, it possesses additional functionality such as reset function, necessary during AD9834 initialization, implemented and routed at the RST pin of the mikroBUS™ socket. This Click board™ can only be operated with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used as a reference for further development.

Waveform 2 Click top side image
Waveform 2 Click lateral side image
Waveform 2 Click bottom side 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

32

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

NC
NC
AN
Reset
PD2
RST
SPI Chip Select
PB2
CS
SPI Clock
PB5
SCK
NC
NC
MISO
SPI Data IN
PB3
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
Enable
PD6
PWM
NC
NC
INT
NC
NC
TX
NC
NC
RX
I2C Clock
PC5
SCL
I2C Data
PC4
SDA
NC
NC
5V
Ground
GND
GND
1

Take a closer look

Schematic

Waveform 2 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

After loading the code example, pressing the "DEBUG" button builds and programs it on the selected setup.

Application Output Step 1

After programming is completed, a header with buttons for various actions available in the IDE appears. By clicking the green "PLAY "button, we start reading the results achieved with Click board™.

Application Output Step 3

Upon completion of programming, the Application Output tab is automatically opened, where the achieved result can be read. In case of an inability to perform the Debug function, check if a proper connection between the MCU used by the setup and the CODEGRIP programmer has been established. A detailed explanation of the CODEGRIP-board connection can be found in the CODEGRIP User Manual. Please find it in the RESOURCES section.

Application Output Step 4

Software Support

Library Description

This library contains API for Waveform 2 Click driver.

Key functions:

  • void waveform2_set_freq ( uint32_t freq ) - Function for setting the output frequency.
  • void waveform2_sine_output ( void ) - Function for setting the sine output.
  • void waveform2_triangle_output ( void ) - Function for setting the triangle output.

Open Source

Code example

This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.

/*!
 * @file main.c
 * @brief Waveform2 Click example
 *
 * # Description
 * This is an example that demonstrates the use of the Waveform 2 Click board.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initialize the communication interface, preforming hardware reset, and configure the click board.
 *
 * ## Application Task
 * Predefined characters are inputed from the serial port.
 * Depending on the character sent the signal frequency, waveform or amplitude
 * will be changed.
 *
 * - Command:
 * [ + ] - Increase frequency
 * [ - ] - Decrease frequency
 * [ t ] - Triangle-shaped signal
 * [ s ] - The signal in the form of a sinusoid
 * 
 * - Additional Functions :
 * aprox_freq_calculation( float freqency ) - This function is used to calculate the aproximate 
 * value that will be written to the frequency set register.
 *
 * @author Stefan Ilic
 *
 */

#include "board.h"
#include "log.h"
#include "waveform2.h"

static waveform2_t waveform2;
static log_t logger;

float value = 100000;
char demo_rx_buf[ 10 ];
char demo_tx_buf[ 10 ] = "MikroE";

/**
 * @brief Aproximate frequency calculation function.
 * @details This function is used to calculate the aproximate value that will be 
 * written to the frequency set register..
 */
uint32_t aprox_freq_calculation ( float freqency );

void application_init ( void ) {
    log_cfg_t log_cfg;  /**< Logger config object. */
    waveform2_cfg_t waveform2_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.
    waveform2_cfg_setup( &waveform2_cfg );
    WAVEFORM2_MAP_MIKROBUS( waveform2_cfg, MIKROBUS_1 );
    err_t init_flag  = waveform2_init( &waveform2, &waveform2_cfg );
    if ( ( I2C_MASTER_ERROR == init_flag ) || ( SPI_MASTER_ERROR == init_flag ) ) {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }
    waveform2_default_cfg ( &waveform2 );

    log_printf( &logger, "---- EEPROM test ----\r\n " );
    log_printf( &logger, ">> Write [MikroE] to address 0x0123\r\n " );
    waveform2_eeprom_write_string( &waveform2, 0x0123, demo_tx_buf, 6 );
    waveform2_eeprom_read_string ( &waveform2, 0x0123, demo_rx_buf, 6 );
    log_printf( &logger, ">> Read data: %s  from address 0x0123.... \r\n ", demo_rx_buf );
    Delay_ms( 1000 );
    waveform2_hw_reset( &waveform2 );
    Delay_ms( 1000 );
    
    log_printf( &logger, "---- Waveform set freqency ----\r\n" );
    int32_t freqency;
    freqency = aprox_freq_calculation( value );
    waveform2_set_freq( &waveform2, freqency );
    waveform2_triangle_output( &waveform2 );
    Delay_ms( 1000 );
    log_info( &logger, " Application Task " );
}

void application_task ( void ) {
    char rx_data;
    uint32_t freq_data;

    if ( log_read( &logger, &rx_data, 1 ) ) {
        switch ( rx_data ) {
            case '+': {
                if ( value > 200000 ) {
                    value = 0;
                }
                value += 100000;
                freq_data = aprox_freq_calculation( value );
                waveform2_set_freq( &waveform2, freq_data );
                log_printf( &logger, ">> Increasing the frequency \r\n " );
                break;
            }

            case '-': {
                if ( value < 200000 ) {
                    value = 400000;
                }
                value -= 100000;
                freq_data = aprox_freq_calculation( value );
                waveform2_set_freq( &waveform2, freq_data );
                log_printf( &logger, ">> Decreasing the frequency \r\n " );
                break;
            }

            case 't': {
                waveform2_triangle_output( &waveform2 );
                log_printf( &logger, ">> Triangle output \r\n " );
                break;
            }

            case 's': {
                waveform2_sine_output( &waveform2 );
                log_printf( &logger,  ">> Sinusoid output \r\n " );
                break;
            }
        }
    }
}

void main ( void ) {
    application_init( );

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

uint32_t aprox_freq_calculation ( float freqency ) {
    uint32_t calculation;
    float WAVEFORM_OSC_FREQ = 50000000.0;
    float WAVEFORM_CONSTANT = 268435456.0; 

    calculation = freqency * ( WAVEFORM_CONSTANT / WAVEFORM_OSC_FREQ );

    return calculation;
}

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

Additional Support

Resources