Establish long-distance wireless transmission with RFM75 and STM32F407VGT6

Stay connected without the hassle

Published Dec 29, 2023

Click board™

ISM Click

Dev Board

Clicker 4 for STM32F4

Compiler

NECTO Studio

MCU

STM32F407VGT6

Unleash the potential of your solution and get efficient, fast, and reliable wireless communication

Hardware Overview

How does it work?

ISM Click is based on the RFM75, a low-power, high-performance 2.4GHz GFSK transceiver operating in the worldwide ISM frequency band from 2400MHz to 2527MHz from RF Solutions. The RFM75 operates in TDD mode, either as a transmitter or as a receiver. Burst mode transmission and up to 2Mbps air data rate make it suitable for ultra-low power consumption applications. The embedded packet processing engines enable their entire operation with a simple MCU as a radio system. Auto re-transmission and auto acknowledge giving reliable link without any MCU interference. A transmitter and receiver must be programmed with the same RF channel frequency to communicate, supporting a programmable air

data rate of 250Kbps, 1Mbps, or 2Mbps. The RF channel frequency determines the center of the channel used by RFM75. The RF_CH register, in register bank 0, sets the frequency according to the following formula F0= 2400 + RF_CH (MHz), where the resolution of the RF channel frequency is 1MHz. ISM Click communicates with MCU using the standard SPI serial interface that operates at clock rates up to 8 MHz. In power-down mode, RFM75 is in Sleep mode with minimal current consumption. The SPI interface is still active in this mode, and all register values are available by the SPI interface. This Click board™ also has a yellow LED indicator routed on the INT pin of the mikroBUS™ socket (provide the user with feedback after

a successfully received package) and a chip-enable function routed on the RST pin of the mikroBUS™ which activates TX or RX mode of the RFM75. Besides, it also has two additional LED indicators, a red and blue LED routed on the AN and PWM pins of the mikroBUS™ socket. The user can use it for visual indication when sending or receiving data. 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.

Features overview

Development board

Clicker 4 for STM32F4 is a compact development board designed as a complete solution that you can use to quickly build your own gadgets with unique functionalities. Featuring an STM32F407VGT6 MCU, four mikroBUS™ sockets for Click boards™ connectivity, power management, and more, it represents a perfect solution for the rapid development of many different types of applications. At its core is an STM32F407VGT6 MCU, a powerful microcontroller by STMicroelectronics based on the high-performance

Arm® Cortex®-M4 32-bit processor core operating at up to 168 MHz frequency. It provides sufficient processing power for the most demanding tasks, allowing Clicker 4 to adapt to any specific application requirements. Besides two 1x20 pin headers, four improved mikroBUS™ sockets represent the most distinctive connectivity feature, allowing access to a huge base of Click boards™, growing on a daily basis. Each section of Clicker 4 is clearly marked, offering an intuitive and clean interface. This makes working with the

development board much simpler and, thus, faster. The usability of Clicker 4 doesn’t end with its ability to accelerate the prototyping and application development stages: it is designed as a complete solution that can be implemented directly into any project, with no additional hardware modifications required. Four mounting holes [4.2mm/0.165”] at all four corners allow simple installation by using mounting screws.

Microcontroller Overview

MCU Card / MCU

Architecture

ARM Cortex-M4

MCU Memory (KB)

Silicon Vendor

STMicroelectronics

Pin count

100

RAM (Bytes)

100

Used MCU Pins

mikroBUS™ mapper

Data Transmission Indicator

PC4

Chip Enable

PC15

RST

SPI Chip Select

PA4

SPI Clock

PA5

SCK

SPI Data OUT

PA6

MISO

SPI Data IN

PA7

MOSI

Power Supply

3.3V

Ground

GND

Data Reception Indicator

PE9

PWM

Interrupt

PD0

INT

SCL

SDA

Ground

GND

Take a closer look

Schematic

Step by step

Project assembly

Clicker 4 for STM32F4 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Clicker 4 for STM32F4 as your development board.

Rotary O 2 Click front image hardware assembly

Clicker 4 STM32F4 MB 1 - upright/background hardware assembly

Clicker 4 for STM32F4 HA MCU Step hardware assembly

Necto No Display image step 8 hardware assembly

Debug Image Necto Step hardware assembly

Track your results in real time

Application Output via Debug Mode

1. Once the code example is loaded, pressing the "DEBUG" button initiates the build process, programs it on the created setup, and enters Debug mode.

2. After the programming is completed, a header with buttons for various actions within the IDE becomes visible. Clicking the green "PLAY" button starts reading the results achieved with the Click board™. The achieved results are displayed in the Application Output tab.

Software Support

Library Description

This library contains API for ISM Click driver.

Key functions:

ism_cfg_setup - Config Object Initialization function.
ism_init - Initialization function.
ism_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 Ism Click example
 *
 * # Description
 * This library contains API for the ISM Click driver.
 * This example transmits/receives and processes data from ISM clicks.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes driver and performs the default configuration. 
 *
 * ## Application Task
 * Transmitter/Receiver task depends on uncommented code.
 * Receiver logging each received byte to the UART for data logging,
 * while transmitter send messages every 1 second.
 *
 * @author Nenad Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "ism.h"

// Comment out the line below in order to switch the application mode to receiver
#define DEMO_APP_TRANSMITTER

static ism_t ism;
static log_t logger;

static uint8_t demo_message_1[ 9 ] = { 'M', 'i', 'k', 'r', 'o', 'E', 13, 10, 0 };
static uint8_t demo_message_2[ 12 ] = { 'I', 'S', 'M', ' ', 'C', 'l', 'i', 'c', 'k', 13, 10, 0 };

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    ism_cfg_t ism_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.
    ism_cfg_setup( &ism_cfg );
    ISM_MAP_MIKROBUS( ism_cfg, MIKROBUS_1 );
    if ( SPI_MASTER_ERROR == ism_init( &ism, &ism_cfg ) ) 
    {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );
        for ( ; ; );
    }

    ism_default_cfg ( &ism );
    Delay_ms ( 100 );
    
#ifdef DEMO_APP_TRANSMITTER
    ism_switch_tx_mode( &ism );
    log_printf( &logger, " Application Mode: Transmitter\r\n" );
#else
    ism_switch_rx_mode( &ism );
    log_printf( &logger, " Application Mode: Receiver\r\n" );
#endif
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
#ifdef DEMO_APP_TRANSMITTER
    ism_transmit_packet( &ism, ISM_CMD_W_TX_PAYLOAD_NOACK, demo_message_1, 9 );
    log_printf( &logger, "  Tx : %s", demo_message_1 );
    Delay_ms ( 1000 );

    ism_transmit_packet( &ism, ISM_CMD_W_TX_PAYLOAD_NOACK, demo_message_2, 12 );
    log_printf( &logger, "  Tx : %s", demo_message_2 );
    Delay_ms ( 1000 );
#else
    uint8_t rx_buf[ ISM_MAX_PACKET_LEN ] = { 0 };

    ism_receive_packet( &ism, &rx_buf[ 0 ] );

    if ( rx_buf[ 0 ] ) 
    {
        log_printf( &logger, "  Rx : %s", rx_buf );
    }
#endif
}

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 main.c
 * @brief Ism Click example
 *
 * # Description
 * This library contains API for the ISM Click driver.
 * This example transmits/receives and processes data from ISM clicks.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes driver and performs the default configuration. 
 *
 * ## Application Task
 * Transmitter/Receiver task depends on uncommented code.
 * Receiver logging each received byte to the UART for data logging,
 * while transmitter send messages every 1 second.
 *
 * @author Nenad Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "ism.h"

// Comment out the line below in order to switch the application mode to receiver
#define DEMO_APP_TRANSMITTER

static ism_t ism;
static log_t logger;

static uint8_t demo_message_1[ 9 ] = { 'M', 'i', 'k', 'r', 'o', 'E', 13, 10, 0 };
static uint8_t demo_message_2[ 12 ] = { 'I', 'S', 'M', ' ', 'C', 'l', 'i', 'c', 'k', 13, 10, 0 };

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    ism_cfg_t ism_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.
    ism_cfg_setup( &ism_cfg );
    ISM_MAP_MIKROBUS( ism_cfg, MIKROBUS_1 );
    if ( SPI_MASTER_ERROR == ism_init( &ism, &ism_cfg ) ) 
    {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );
        for ( ; ; );
    }

    ism_default_cfg ( &ism );
    Delay_ms ( 100 );
    
#ifdef DEMO_APP_TRANSMITTER
    ism_switch_tx_mode( &ism );
    log_printf( &logger, " Application Mode: Transmitter\r\n" );
#else
    ism_switch_rx_mode( &ism );
    log_printf( &logger, " Application Mode: Receiver\r\n" );
#endif
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
#ifdef DEMO_APP_TRANSMITTER
    ism_transmit_packet( &ism, ISM_CMD_W_TX_PAYLOAD_NOACK, demo_message_1, 9 );
    log_printf( &logger, "  Tx : %s", demo_message_1 );
    Delay_ms ( 1000 );

    ism_transmit_packet( &ism, ISM_CMD_W_TX_PAYLOAD_NOACK, demo_message_2, 12 );
    log_printf( &logger, "  Tx : %s", demo_message_2 );
    Delay_ms ( 1000 );
#else
    uint8_t rx_buf[ ISM_MAX_PACKET_LEN ] = { 0 };

    ism_receive_packet( &ism, &rx_buf[ 0 ] );

    if ( rx_buf[ 0 ] ) 
    {
        log_printf( &logger, "  Rx : %s", rx_buf );
    }
#endif
}

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 main.c
 * @brief Ism Click example
 *
 * # Description
 * This library contains API for the ISM Click driver.
 * This example transmits/receives and processes data from ISM clicks.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes driver and performs the default configuration. 
 *
 * ## Application Task
 * Transmitter/Receiver task depends on uncommented code.
 * Receiver logging each received byte to the UART for data logging,
 * while transmitter send messages every 1 second.
 *
 * @author Nenad Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "ism.h"

// Comment out the line below in order to switch the application mode to receiver
#define DEMO_APP_TRANSMITTER

static ism_t ism;
static log_t logger;

static uint8_t demo_message_1[ 9 ] = { 'M', 'i', 'k', 'r', 'o', 'E', 13, 10, 0 };
static uint8_t demo_message_2[ 12 ] = { 'I', 'S', 'M', ' ', 'C', 'l', 'i', 'c', 'k', 13, 10, 0 };

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    ism_cfg_t ism_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.
    ism_cfg_setup( &ism_cfg );
    ISM_MAP_MIKROBUS( ism_cfg, MIKROBUS_1 );
    if ( SPI_MASTER_ERROR == ism_init( &ism, &ism_cfg ) ) 
    {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );
        for ( ; ; );
    }

    ism_default_cfg ( &ism );
    Delay_ms ( 100 );
    
#ifdef DEMO_APP_TRANSMITTER
    ism_switch_tx_mode( &ism );
    log_printf( &logger, " Application Mode: Transmitter\r\n" );
#else
    ism_switch_rx_mode( &ism );
    log_printf( &logger, " Application Mode: Receiver\r\n" );
#endif
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
#ifdef DEMO_APP_TRANSMITTER
    ism_transmit_packet( &ism, ISM_CMD_W_TX_PAYLOAD_NOACK, demo_message_1, 9 );
    log_printf( &logger, "  Tx : %s", demo_message_1 );
    Delay_ms ( 1000 );

    ism_transmit_packet( &ism, ISM_CMD_W_TX_PAYLOAD_NOACK, demo_message_2, 12 );
    log_printf( &logger, "  Tx : %s", demo_message_2 );
    Delay_ms ( 1000 );
#else
    uint8_t rx_buf[ ISM_MAX_PACKET_LEN ] = { 0 };

    ism_receive_packet( &ism, &rx_buf[ 0 ] );

    if ( rx_buf[ 0 ] ) 
    {
        log_printf( &logger, "  Rx : %s", rx_buf );
    }
#endif
}

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