30 min

Build a various waveform signal generator with AD9837 and TM4C123GH6PZ

Waves of Fun

Waveform 3 Click with UNI Clicker

Published May 27, 2023

Click board™

Waveform 3 Click

Development board

UNI Clicker


NECTO Studio



Design and develop a waveform generator that produces specific waveforms to simulate sensor inputs for testing and validation purposes



Hardware Overview

How does it work?

Waveform 3 Click is based on the AD9837, a fully integrated direct digital synthesis (DDS) device capable of producing high-performance sine and triangular wave outputs from Analog Devices. It also has an internal comparator that allows the creation of a square wave for clock generation. With 28-bit wide frequency registers, the output frequency and phase are software-programmable, allowing easy tuning. The AD9837 is capable of a broad range of complex and straightforward modulation schemes fully implemented in the digital domain, allowing the accurate and precise realization of complex modulation algorithms using DSP techniques. The internal circuitry of the AD9837 consists of a numerically controlled oscillator (NCO), frequency and phase modulators, SIN

ROM, a DAC, a comparator, and a regulator. Also, it has a high-performance, onboard 16MHz trimmed general oscillator that can serve as the master clock for the AD9837 achieving a resolution of 0.06Hz. The AD9837 offers a variety of outputs available from an onboard output SMA connector. The various output options (sine, triangular, and square wave) from the AD9837 make this Click board™ suitable for various applications, including modulation applications. It is also ideal for signal generator applications, and with its low current consumption, it is also suitable for applications in which it can serve as a local oscillator. The Waveform 3 Click communicates with MCU using the 3-Wire SPI serial interface compatible with standard SPI, QSPI™, MICROWIRE™, and DSP interface

standards and operates at clock rates up to 40MHz. Besides, it possesses additional functionality, such as a programmable Sleep function that allows external control of the Power-Down mode and Reset function, which resets the appropriate internal registers to 0 to provide an analog output of mid-scale. Remembering that the reset function does not reset the phase, frequency, or control registers is essential. 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 3 Click top side image
Waveform 3 Click lateral side image
Waveform 3 Click bottom side image

Features overview

Development board

UNI Clicker is a compact development board designed as a complete solution that brings the flexibility of add-on Click boards™ to your favorite microcontroller, making it a perfect starter kit for implementing your ideas. It supports a wide range of microcontrollers, such as different ARM, PIC32, dsPIC, PIC, and AVR from various vendors like Microchip, ST, NXP, and TI (regardless of their number of pins), four mikroBUS™ sockets for Click board™ connectivity, a USB connector, LED indicators, buttons, a debugger/programmer connector, and two 26-pin headers for interfacing with external electronics. Thanks to innovative manufacturing technology, it allows you to build

gadgets with unique functionalities and features quickly. Each part of the UNI Clicker development kit contains the components necessary for the most efficient operation of the same board. In addition to the possibility of choosing the UNI Clicker programming method, using a third-party programmer or CODEGRIP/mikroProg connected to onboard JTAG/SWD header, the UNI Clicker board also includes a clean and regulated power supply module for the development kit. It provides two ways of board-powering; through the USB Type-C (USB-C) connector, where onboard voltage regulators provide the appropriate voltage levels to each component on the board, or using a Li-Po/Li

Ion battery via an onboard battery connector. All communication methods that mikroBUS™ itself supports are on this board (plus USB HOST/DEVICE), including the well-established mikroBUS™ socket, a standardized socket for the MCU card (SiBRAIN standard), and several user-configurable buttons and LED indicators. UNI Clicker is an integral part of the Mikroe ecosystem, allowing you to create a new application in minutes. Natively supported by Mikroe software tools, it covers many aspects of prototyping thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.

UNI clicker double image

Microcontroller Overview

MCU Card / MCU



8th Generation


ARM Cortex-M4

MCU Memory (KB)


Silicon Vendor

Texas Instruments

Pin count


RAM (Bytes)


Used MCU Pins

mikroBUS™ mapper

SPI Chip Select
SPI Clock
Power Supply

Take a closer look


Waveform 3 Click Schematic schematic

Step by step

Project assembly

UNI Clicker front image hardware assembly

Start by selecting your development board and Click board™. Begin with the UNI Clicker as your development board.

UNI Clicker front image hardware assembly
GNSS2 Click front image hardware assembly
SiBRAIN for STM32F745VG front image hardware assembly
Prog-cut hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
UNI Clicker 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
Necto image step 7 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 3 Click driver.

Key functions:

  • waveform3_cfg_setup - Config Object Initialization function.
  • waveform3_init - Initialization function.
  • waveform3_default_cfg - Click Default Configuration function.

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 Waveform3 Click example
 * # Description
 * This demo app shows the basic capabilities of Waveform 3
 * click board. First, the sinusoidal wave is incremented
 * to targeted frequency for visually pleasing introduction
 * after which it changes between 4 modes of output.
 * The demo application is composed of two sections :
 * ## Application Init
 * Application initializes the UART LOG and SPI drivers,
 * resets the device and sets frequency and phase shift to
 * default values. In the end, the mode is set with the 
 * preferred freq and phase channel.
 * ## Application Task
 * Task commences with the start frequency rising up to
 * the targeted one. When it reaches desired frequency,
 * the mode changes every 5 seconds which includes: 
 * sinusoidal, triangular, DAC divided by 2 and DAC
 * outputs respectively.
 * *note:*
 * Waveform 3 click might not provide a high enough peak to peak signal on higher frequencies.
 * The user can freely implement custom buffer for the output stage.
 * Special thanks to my esteemed co-worker Nenad Filipovic for support during firmware development.
 * @author Stefan Nikolic

#include "board.h"
#include "log.h"
#include "waveform3.h"

static waveform3_t waveform3;
static log_t logger;

static uint32_t start_frequency = 100;
static uint32_t rising_factor = 10;
static uint32_t target_frequency = 10000;

void application_init ( void ) {
    log_cfg_t log_cfg;              /**< Logger config object. */
    waveform3_cfg_t waveform3_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.

    waveform3_cfg_setup( &waveform3_cfg );
    WAVEFORM3_MAP_MIKROBUS( waveform3_cfg, MIKROBUS_1 );
    err_t init_flag  = waveform3_init( &waveform3, &waveform3_cfg );
    if ( init_flag == SPI_MASTER_ERROR ) {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );

    waveform3_default_cfg( &waveform3 );
    Delay_ms( 500 );
    log_info( &logger, " Application Task " );

void application_task ( void ) {
    uint8_t cfg_mode_switch;
    if ( start_frequency < target_frequency ) {
        if ( start_frequency / rising_factor < 100 ) {
            start_frequency += rising_factor;
            waveform3_set_freq( &waveform3, start_frequency, WAVEFORM3_CFG_FREQ_REG0 );
            Delay_ms( 5 );
        } else {
            rising_factor += 10;
    } else {
        for ( cfg_mode_switch = 0 ; cfg_mode_switch < 4 ; cfg_mode_switch++ ) {
        waveform3_set_mode( &waveform3, cfg_mode_switch, WAVEFORM3_CFG_FREQ_REG0, WAVEFORM3_CFG_PHASE_REG0 );
        Delay_ms( 5000 );

void main ( void ) {
    application_init( );

    for ( ; ; ) {
        application_task( );

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

Additional Support