Intermediate
30 min

Shape your signals with AD9834 and STM32F091RC

Frequency stimulus/waveform generation

Waveform 2 Click with Nucleo-64 with STM32F091RC MCU

Published Feb 26, 2024

Click board™

Waveform 2 Click

Dev. board

Nucleo-64 with STM32F091RC MCU

Compiler

NECTO Studio

MCU

STM32F091RC

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

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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

Nucleo-64 with STM32F091RC MCU offers a cost-effective and adaptable platform for developers to explore new ideas and prototype their designs. This board harnesses the versatility of the STM32 microcontroller, enabling users to select the optimal balance of performance and power consumption for their projects. It accommodates the STM32 microcontroller in the LQFP64 package and includes essential components such as a user LED, which doubles as an ARDUINO® signal, alongside user and reset push-buttons, and a 32.768kHz crystal oscillator for precise timing operations. Designed with expansion and flexibility in mind, the Nucleo-64 board features an ARDUINO® Uno V3 expansion connector and ST morpho extension pin

headers, granting complete access to the STM32's I/Os for comprehensive project integration. Power supply options are adaptable, supporting ST-LINK USB VBUS or external power sources, ensuring adaptability in various development environments. The board also has an on-board ST-LINK debugger/programmer with USB re-enumeration capability, simplifying the programming and debugging process. Moreover, the board is designed to simplify advanced development with its external SMPS for efficient Vcore logic supply, support for USB Device full speed or USB SNK/UFP full speed, and built-in cryptographic features, enhancing both the power efficiency and security of projects. Additional connectivity is

provided through dedicated connectors for external SMPS experimentation, a USB connector for the ST-LINK, and a MIPI® debug connector, expanding the possibilities for hardware interfacing and experimentation. Developers will find extensive support through comprehensive free software libraries and examples, courtesy of the STM32Cube MCU Package. This, combined with compatibility with a wide array of Integrated Development Environments (IDEs), including IAR Embedded Workbench®, MDK-ARM, and STM32CubeIDE, ensures a smooth and efficient development experience, allowing users to fully leverage the capabilities of the Nucleo-64 board in their projects.

Nucleo 64 with STM32F091RC MCU double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

ARM Cortex-M0

MCU Memory (KB)

256

Silicon Vendor

STMicroelectronics

Pin count

64

RAM (Bytes)

32768

You complete me!

Accessories

Click Shield for Nucleo-64 comes equipped with two proprietary mikroBUS™ sockets, allowing all the Click board™ devices to be interfaced with the STM32 Nucleo-64 board with no effort. This way, Mikroe allows its users to add any functionality from our ever-growing range of Click boards™, such as WiFi, GSM, GPS, Bluetooth, ZigBee, environmental sensors, LEDs, speech recognition, motor control, movement sensors, and many more. More than 1537 Click boards™, which can be stacked and integrated, are at your disposal. The STM32 Nucleo-64 boards are based on the microcontrollers in 64-pin packages, a 32-bit MCU with an ARM Cortex M4 processor operating at 84MHz, 512Kb Flash, and 96KB SRAM, divided into two regions where the top section represents the ST-Link/V2 debugger and programmer while the bottom section of the board is an actual development board. These boards are controlled and powered conveniently through a USB connection to program and efficiently debug the Nucleo-64 board out of the box, with an additional USB cable connected to the USB mini port on the board. Most of the STM32 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 STM32 Nucleo-64 board with our Click Shield for Nucleo-64, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.

Click Shield for Nucleo-64 accessories 1 image

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Reset
PC12
RST
SPI Chip Select
PB12
CS
SPI Clock
PB3
SCK
NC
NC
MISO
SPI Data IN
PB5
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
Enable
PC8
PWM
NC
NC
INT
NC
NC
TX
NC
NC
RX
I2C Clock
PB8
SCL
I2C Data
PB9
SDA
NC
NC
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

Waveform 2 Click Schematic schematic

Step by step

Project assembly

Click Shield for Nucleo-64 accessories 1 image hardware assembly

Start by selecting your development board and Click board™. Begin with the Nucleo-64 with STM32F091RC MCU as your development board.

Click Shield for Nucleo-64 accessories 1 image hardware assembly
Nucleo 64 with STM32F401RE MCU front image hardware assembly
LTE IoT 5 Click front image hardware assembly
Prog-cut hardware assembly
LTE IoT 5 Click complete accessories setup image hardware assembly
Nucleo-64 with STM32XXX MCU Access MB 1 Mini B Conn - 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
Clicker 4 for STM32F4 HA 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 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

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 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

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