Intermediate
20 min

Achieve long-range, low-power communication ideal for IoT applications with RA-08 and STM32F407VGT6

LoRa module for ultra-long distance spread spectrum communications

LR 9 Click with Clicker 4 for STM32F4

Published Apr 04, 2024

Click board™

LR 9 Click

Dev Board

Clicker 4 for STM32F4

Compiler

NECTO Studio

MCU

STM32F407VGT6

Ideal for sectors requiring long-distance, low-power communication, such as smart metering, supply chain and logistics, home automation, and security systems

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Hardware Overview

How does it work?

LR 9 Click is based on the RA-08, a LoRaWAN module from Ai-Thinker Technology. This module is made for ultra-long-range spread spectrum communication tasks powered by the ASR6601. The ASR6601, an LPWAN wireless communication system-on-chip (SoC), combines RF transceivers, modems, and a 32-bit RISC microcontroller (MCU). The embedded MCU, leveraging an ARM core, operates at a frequency of 48MHz. The RA-08 is designed to work with LoRa modulation and the conventional (G)FSK modulation within the LPWAN domain. Furthermore, it supports BPSK and (G)MSK modulation for transmission, with the receiver accommodating (G)MSK modulation. Designed for LPWAN applications, the RA-08 module delivers long-distance, ultra-low power connectivity. It finds its applications in various sectors, including smart metering, supply chain and logistics management, building automation for homes, security systems, and remote-controlled

irrigation systems. Diving deeper into the specifics, the module supports a frequency range from 410MHz to 525MHz and can transmit at a maximum power of +22dBm. It boasts embedded storage with 128KB of FLASH and 16KB of SRAM, alongside support for several sleep modes, with a deep sleep current as low as 0.9uA. Additional functionalities of the LR 9 Click include communication capabilities with the host MCU via a UART interface, set by default to a baud rate of 115200bps. A switch on the board allows the selection of the UART interface's function—either as the main serial communication port for exchanging AT commands (in the LPRX position) or as a serial port for firmware flashing (in the RX position). Moreover, for developers looking to build their software from scratch, the module also includes I2C communication capabilities. The board does not limit itself to UART and I2C interface pins; it also features pins like the RST pin for module

resetting (which can also be achieved through a RESET button) and a BT pin for firmware flashing (accessible through a BOOT button). This frees programming and software development through the SWD interface pins on the board's right side. Also, an RGB LED serves as a module status indicator and is configurable by the user. LR 9 Click also features the SMA antenna connector with an impedance of 50Ω, compatible with various antennas available from MIKROE, like the Rubber Antenna 433MHz, to enhance its connectivity. 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.

LR 9 Click hardware overview image

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.

Clicker 4 for STM32F4 double image

Microcontroller Overview

MCU Card / MCU

default

Architecture

ARM Cortex-M4

MCU Memory (KB)

10

Silicon Vendor

STMicroelectronics

Pin count

100

RAM (Bytes)

100

You complete me!

Accessories

Right angle 433MHz rubber antenna boasts a frequency range of 433MHz, ensuring optimal performance within this spectrum. With a 50Ohm impedance, it facilitates efficient signal transmission. The antenna's vertical polarization enhances signal reception in a specific orientation. Featuring a 1.5dB gain, it can improve signal strength to some extent. The antenna can handle a maximum input power of 50W, making it suitable for various applications. Its compact 50mm length minimizes spatial requirements. Equipped with an SMA male connector, it easily interfaces with compatible devices. This antenna is an adaptable solution for wireless communication needs, particularly when vertical polarization is crucial.

LR 9 Click accessories 1 image

Used MCU Pins

mikroBUS™ mapper

FW Flash
PC4
AN
Reset
PC15
RST
ID COMM
PA4
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
NC
NC
INT
UART TX
PA2
TX
UART RX
PA3
RX
I2C Clock
PB10
SCL
I2C Data
PB11
SDA
NC
NC
5V
Ground
GND
GND
1

Take a closer look

Schematic

LR 9 Click Schematic 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.

Clicker 4 for STM32F4 front image hardware assembly
LTE IoT 5 Click front image hardware assembly
LTE IoT 5 Click complete accessories setup image hardware assembly
Clicker 4 STM32F4 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
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

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 LR 9 Click driver.

Key functions:

  • lr9_send_data_frame - This function sends the desired data frame by using the UART serial interface

  • lr9_inquire_command - Using the UART serial interface, this function writes the desired query command with or without the included equals symbol

  • lr9_write_command - This function writes a desired command and parameter by using the UART serial interface

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 LR 9 Click Example.
 *
 * # Description
 * This example demonstrates the use of LR 9 click board by processing
 * the incoming data and displaying them on the USB UART.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and performs a hardware reset of the device.
 *
 * ## Application Task
 * Depending on the selected mode, the application demo 
 * receives and processes all incoming data or sends the LoRa packet demo string.
 * Results are being sent to the UART Terminal, where you can track their changes.
 *
 * ## Additional Function
 * - static void lr9_clear_app_buf ( void )
 * - static void lr9_log_app_buf ( void )
 * - static void lr9_log_receiver ( void )
 * - static void lr9_log_response ( void )
 * - static err_t lr9_process ( lr9_t *ctx )
 *
 * @author Nenad Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "lr9.h"
#include "conversions.h"

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

// Default RF configuration
#define LR9_RF_CFG_DEFAULT_TX       "433000000,1,1,1,22,1"
#define LR9_RF_CFG_DEFAULT_RX       "433000000,1,1,1,1"
#define LR9_DEMO_STRING             "MikroE"

// Receiver string sequences
#define PROCESS_START_RECEIVE       "Recv:"
#define PROCESS_ATDTRX              "AT"

// Response timeout
#define RESPONSE_TIMEOUT            100000

// Application buffer size
#define APP_BUFFER_SIZE             500
#define PROCESS_BUFFER_SIZE         200

static lr9_t lr9;
static log_t logger;

static uint8_t app_buf[ APP_BUFFER_SIZE ] = { 0 };
static int32_t app_buf_len = 0;

/**
 * @brief LR 9 clearing application buffer.
 * @details This function clears memory of application buffer and reset its length.
 * @note None.
 */
static void lr9_clear_app_buf ( void );

/**
 * @brief LR 9 log application buffer.
 * @details This function logs data from application buffer to USB UART.
 * @note None.
 */
static void lr9_log_app_buf ( void );

/**
 * @brief LR 9 log receiver data.
 * @details This function logs data from receiver application buffer to USB UART.
 * @note None.
 */
static void lr9_log_receiver ( void );

/**
 * @brief LR 9 log response.
 * @details This function reads data from device and 
 * concatenates and logs data to application buffer to USB UART.
 * @note None.
 */
static void lr9_log_response ( void );

/**
 * @brief LR 9 data reading function.
 * @details This function reads data from device and concatenates data to application buffer. 
 * @param[in] ctx : Click context object.
 * See #lr9_t object definition for detailed explanation.
 * @return @li @c  0 - Read some data.
 *         @li @c -1 - Nothing is read.
 * See #err_t definition for detailed explanation.
 * @note None.
 */
static err_t lr9_process ( lr9_t *ctx );

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    lr9_cfg_t lr9_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.
    lr9_cfg_setup( &lr9_cfg );
    LR9_MAP_MIKROBUS( lr9_cfg, MIKROBUS_1 );
    if ( UART_ERROR == lr9_init( &lr9, &lr9_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    lr9_hw_reset( &lr9 );
    Delay_ms( 500 );

    lr9_inquire_command( &lr9, LR9_CMD_CTXADDRSET, LR9_EQUAL_ENABLE );
    lr9_log_response( );
    Delay_ms( 500 );

    lr9_inquire_command( &lr9, LR9_CMD_CADDRSET, LR9_EQUAL_ENABLE );
    lr9_log_response( );
    Delay_ms( 500 );

#ifdef DEMO_APP_TRANSMITTER
    log_printf( &logger, " > Transmitter < \r\n" );
    lr9_write_command( &lr9, LR9_CMD_CTX , LR9_RF_CFG_DEFAULT_TX );
    lr9_log_response( );
    Delay_ms( 500 );
#else
    log_printf( &logger, " > Receiver < \r\n" );
    lr9_write_command( &lr9, LR9_CMD_CRXS , LR9_RF_CFG_DEFAULT_RX );
    lr9_log_response( );
    Delay_ms( 500 );
#endif

    lr9_log_response( );
    Delay_ms( 500 );
}

void application_task ( void ) 
{
#ifdef DEMO_APP_TRANSMITTER
    lr9_send_data_frame( &lr9, LR9_DTRX_CONFIG_DATA, LR9_NB_TRIALS_2, LR9_DEMO_STRING );
    lr9_log_response( );
    Delay_ms( 2000 );
#else
    lr9_log_receiver( );
#endif
}

int main ( void ) 
{
    application_init( );

    for ( ; ; ) 
    {
        application_task( );
    }
    
    return 0;
}

static void lr9_clear_app_buf ( void ) 
{
    memset( app_buf, 0, app_buf_len );
    app_buf_len = 0;
}

static void lr9_log_app_buf ( void )
{
    for ( int32_t buf_cnt = 0; buf_cnt < app_buf_len; buf_cnt++ )
    {
        log_printf( &logger, "%c", app_buf[ buf_cnt ] );
    }
}

static void lr9_log_receiver ( void )
{
    uint32_t timeout_cnt = 0;
    lr9_clear_app_buf( );
    lr9_process( &lr9 );
    while ( 0 == strstr( app_buf, PROCESS_START_RECEIVE ) )
    {
        lr9_process( &lr9 );
        if ( timeout_cnt++ > RESPONSE_TIMEOUT )
        {
            lr9_clear_app_buf( );
            log_printf( &logger, " Timeout\r\n" );
            break;
        }
        Delay_ms( 1 );
    }
    lr9_process( &lr9 );
    if ( strstr( app_buf, PROCESS_ATDTRX ) )
    {
        log_printf( &logger, " Receive: " );
        for ( int32_t buf_cnt = 15; buf_cnt < 15 + strlen( LR9_DEMO_STRING ); buf_cnt++ )
        {
            log_printf( &logger, "%c", app_buf[ buf_cnt ] );
        }
        log_printf( &logger, "\r\n" );
    }
    lr9_clear_app_buf( );
}

static void lr9_log_response ( void )
{
    if ( LR9_OK == lr9_process( &lr9 ) ) 
    {
        lr9_log_app_buf( );
        lr9_clear_app_buf( );
    }
}

static err_t lr9_process ( lr9_t *ctx ) 
{
    uint8_t rx_buf[ PROCESS_BUFFER_SIZE ] = { 0 };
    int32_t overflow_bytes = 0;
    int32_t rx_cnt = 0;
    int32_t rx_size = lr9_generic_read( ctx, rx_buf, PROCESS_BUFFER_SIZE );
    if ( ( rx_size > 0 ) && ( rx_size <= APP_BUFFER_SIZE ) ) 
    {
        if ( ( app_buf_len + rx_size ) > APP_BUFFER_SIZE ) 
        {
            overflow_bytes = ( app_buf_len + rx_size ) - APP_BUFFER_SIZE;
            app_buf_len = APP_BUFFER_SIZE - rx_size;
            memmove ( app_buf, &app_buf[ overflow_bytes ], app_buf_len );
            memset ( &app_buf[ app_buf_len ], 0, overflow_bytes );
        }
        for ( rx_cnt = 0; rx_cnt < rx_size; rx_cnt++ ) 
        {
            if ( rx_buf[ rx_cnt ] ) 
            {
                app_buf[ app_buf_len++ ] = rx_buf[ rx_cnt ];
            }
        }
        return LR9_OK;
    }
    return LR9_ERROR;
}

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

Additional Support

Resources