Intermediate
30 min

Turn your IoT vision into reality with BC95-G and STM32G071RB

Elevating efficiency with multiband NB technology

NB IoT Click with Nucleo 64 with STM32G071RB MCU

Published Oct 08, 2024

Click board™

NB IoT Click

Dev. board

Nucleo 64 with STM32G071RB MCU

Compiler

NECTO Studio

MCU

STM32G071RB

Reinvent connectivity, connect devices seamlessly, and achieve a new level of control and efficiency in your IoT projects

A

A

Hardware Overview

How does it work?

NB IoT Click is based on the BC95-G module from Quectel Wireless Solutions, which supports LTE NB1 technology, developed with IoT applications in mind. It supports several NB frequency bands: B1, B3, B5, B8, B20, and B28. The module supports point-to-point MO and MT messages, widely used for M2M communication. Packed with the set of protocols that allow data and SMS transfer using the NB1 technology and the ultra-low power consumption makes this module a perfect choice when it comes to building IoT applications. As mentioned before, BC95-G module is the main component of the click board and it consists of a number of internal blocks or sections, such as the RF Transceiver section, Flash SRAM section, Power Management section, and the cellular baseband processor with the peripheral interfaces. BC95 module supports several peripheral interfaces, including two UART interfaces (including the main UART and debug UART interface), USIM card interface, and GPIO interface. The main UART interface can be used for the AT command communication and data transmission. It supports baud rates of 9600 bps. The main UART interface can also be used for the firmware upgrade. In that case, a baud rate of 115200 bps is used. The Quectel BC95 module has to be powered by a clean and stable power supply. The voltage needed for the module to work properly is 4V and it is derived from the 5V mikroBUS™ rail, through the MCP1826, a 1A low drop output (LDO) regulator

from Microchip. Although the Quectel BC95 module is an ultra-low power device, its power consumption can briefly peak sometimes, so 1A LDO had to be used. The BC95 module does not have a dedicated USB interface, therefore a USB-to-UART circuit had to be added to the NB IoT click to provide USB to UART conversion. The FT230X, a highly integrated USB-UART bridge solution from FTDI is used, offering very simple integration thanks to its compact size and a small number of external components required. Two LEDs are used to signalize the data traffic through this IC: the red LED labeled as TX indicates the UART transmission, while the yellow LED labeled as RX indicates the UART reception. This Click board™ is equipped with the micro USB connector. It allows the module to be powered and configured by a personal computer. Quectel Wireless Solutions Company offers a software suite which can be used to configure the BC95 module. However, the FT230X IC requires drivers in order to work. FTDI offers drivers for all major OSes on their official driver download web page. Also, Windows OS drivers are included in the download section, below. The micro SIM card holder on the back of the Click board™ is used to install the SIM card. This device cannot be used without a valid SIM card which allows connection to the cellular network. Digital sections of the BC95 module are supplied with power by an integrated LDO regulator, so it is necessary to convert the logic

voltage level of the microcontroller (MCU) communication lines. By utilizing the LDO output (routed through the MOSFET switching circuitry), the needed reference voltage is provided for one side of the TXB0106, a 6bit bi-directional logic voltage level converter. The reference voltage for the other side of the TXB0106 is taken from the 3.3V power rail of the mikroBUS™. The small switching circuitry composed of a few signal-level MOSFETs is used to provide a way to switch off the FT230X when the Click board™ is inserted into the mikroBUS™ socket. This allows uninterrupted communication with the host MCU. The STAT pin is used to signalize the status of the device. This pin is routed both to the mikroBUS™ AN pin through the TXB0106 level translator, and the yellow LED labeled STAT, which is used to visually indicate the device status. The module can be reset by pulling the RST pin of the mikroBUS™ pin to a LOW logic level. This pin is pulled up to a HIGH level by an internal pull-up resistor. Besides the hardware reset, the module can also be reset by using the AT command. More information about the available AT commands can be found in the download section, below. However, the Click board™ comes supported by the mikroSDK library. The library contains functions which simplify the software development, integrating several AT commands into a single function call. Using mikroSDK makes the code way more readable, but more importantly - easily portable.

NB IoT Click hardware overview image

Features overview

Development board

Nucleo-64 with STM32G071RB 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 STM32G071RB MCU double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

ARM Cortex-M0

MCU Memory (KB)

128

Silicon Vendor

STMicroelectronics

Pin count

64

RAM (Bytes)

36864

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

LTE Flat Rotation Antenna is a versatile choice for boosting the performance of 3G/4G LTE devices. With a wide frequency range of 700-2700MHz, it ensures optimal connectivity on major cellular bands worldwide. This flat antenna features an SMA male connector, making it easy to attach directly to your device or SMA module connector. One of its standout features is its adjustable angle, which can be set in 45⁰ increments (0⁰/45⁰/90⁰), allowing you to fine-tune the antenna's orientation for maximum signal reception. With an impedance of 50Ω and a VSW Ratio of <2.0:1, this antenna ensures a reliable and efficient connection. Its 5dB gain, vertical polarization, and omnidirectional radiation pattern enhance signal strength, making it suitable for various applications. Measuring 196mm in length and 38mm in width, this antenna offers a compact yet effective solution for improving your connectivity. With a maximum input power of 50W, it can handle the demands of various devices.

NB IoT Click accessories image

Used MCU Pins

mikroBUS™ mapper

Network Status
PC0
AN
Module Reset
PC12
RST
NC
NC
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
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

NB IoT 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 STM32G071RB 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 NB IoT Click driver.

Key functions:

  • nbiot_send_cmd - Send command function

  • nbiot_power_on - NB IoT module power on

  • nbiot_generic_write - NB IoT data writing function

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 
 * \brief NbIot Click example
 * 
* # Description
 * This example reads and processes data from NB IoT Clicks.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes driver, wake-up module and sets default configuration 
 * for connecting device to network.
 * 
 * ## Application Task  
 * Waits for device to connect to network and then checks the signal quality 
 * every 5 seconds. All data is being logged on USB UART where you can track their changes.
 * 
 * ## Additional Function
 * - static void nbiot_clear_app_buf ( void )
 * - static void nbiot_error_check( err_t error_flag )
 * - static void nbiot_log_app_buf ( void )
 * - static void nbiot_check_connection( void )
 * - static err_t nbiot_rsp_check ( void )
 * - static err_t nbiot_process ( void )
 * 
 * @note 
 * In order for the example to work, a valid SIM card needs to be entered.
 * 
 * @author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "nbiot.h"

#define APP_OK                              0
#define APP_ERROR_DRIVER                    -1
#define APP_ERROR_OVERFLOW                  -2
#define APP_ERROR_TIMEOUT                   -3

#define RSP_OK                              "OK"
#define RSP_ERROR                           "ERROR"

#define PROCESS_BUFFER_SIZE                 500

#define WAIT_FOR_CONNECTION                 0
#define CONNECTED_TO_NETWORK                1

static nbiot_t nbiot;
static log_t logger;

static char app_buf[ PROCESS_BUFFER_SIZE ]  = { 0 };
static int32_t app_buf_len                  = 0;
static int32_t app_buf_cnt                  = 0;

static uint8_t app_connection_status        = WAIT_FOR_CONNECTION;

static err_t app_error_flag;

/**
 * @brief NB IoT clearing application buffer.
 * @details This function clears memory of application buffer and reset its length and counter.
 * @note None.
 */
static void nbiot_clear_app_buf ( void );

/**
 * @brief NB IoT data reading function.
 * @details This function reads data from device and concats data to application buffer.
 * 
 * @return @li @c  0 - Read some data.
 *         @li @c -1 - Nothing is read.
 *         @li @c -2 - Application buffer overflow.
 *
 * See #err_t definition for detailed explanation.
 * @note None.
 */
static err_t nbiot_process ( void );

/**
 * @brief NB IoT check for errors.
 * @details This function checks for different types of errors and logs them on UART.
 * @note None.
 */
static void nbiot_error_check( err_t error_flag );

/**
 * @brief NB IoT logs application buffer.
 * @details This function logs data from application buffer.
 * @note None.
 */
static void nbiot_log_app_buf ( void );

/**
 * @brief NB IoT response check.
 * @details This function checks for response and returns the status of response.
 * 
 * @return application status.
 * See #err_t definition for detailed explanation.
 * @note None.
 */
static err_t nbiot_rsp_check ( void );

/**
 * @brief NB IoT chek connection.
 * @details This function checks connection to the network and 
 *          logs that status to UART.
 * 
 * @note None.
 */
static void nbiot_check_connection( void );

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    nbiot_cfg_t nbiot_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 " );
    Delay_ms ( 1000 );
    
    // Click initialization.
    nbiot_cfg_setup( &nbiot_cfg );
    NBIOT_MAP_MIKROBUS( nbiot_cfg, MIKROBUS_1 );
    err_t init_flag  = nbiot_init( &nbiot, &nbiot_cfg );
    if ( init_flag == UART_ERROR )
    {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }
    
    log_info( &logger, " Power on device... " );
    nbiot_power_on( &nbiot );
    // dummy read
    app_error_flag = nbiot_rsp_check(  );
    nbiot_error_check( app_error_flag );
    
    // AT
    nbiot_send_cmd( &nbiot, NBIOT_CMD_AT );
    app_error_flag = nbiot_rsp_check( );
    nbiot_error_check( app_error_flag );
    Delay_ms ( 500 );
    
    // ATI - product information
    nbiot_send_cmd( &nbiot, NBIOT_CMD_ATI );
    app_error_flag = nbiot_rsp_check(  );
    nbiot_error_check( app_error_flag );
    Delay_ms ( 500 );
    
    // CGMR - firmware version
    nbiot_send_cmd( &nbiot, NBIOT_CMD_CGMR );
    app_error_flag = nbiot_rsp_check(  );
    nbiot_error_check( app_error_flag );
    Delay_ms ( 1000 );
    
    // COPS - deregister from network
    nbiot_send_cmd_with_parameter( &nbiot, NBIOT_CMD_COPS, "2" );
    app_error_flag = nbiot_rsp_check(  );
    nbiot_error_check( app_error_flag );
    Delay_ms ( 1000 );
     
    // CFUN - full funtionality
    nbiot_send_cmd_with_parameter( &nbiot, NBIOT_CMD_CFUN, "1" );
    app_error_flag = nbiot_rsp_check(  );
    nbiot_error_check( app_error_flag );
    Delay_ms ( 500 );
    
    // COPS - automatic mode
    nbiot_send_cmd_with_parameter( &nbiot, NBIOT_CMD_COPS, "0" );
    app_error_flag = nbiot_rsp_check(  );
    nbiot_error_check( app_error_flag );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    
    // CEREG - network registration status
    nbiot_send_cmd_with_parameter( &nbiot, NBIOT_CMD_CEREG, "2" );
    app_error_flag = nbiot_rsp_check(  );
    nbiot_error_check( app_error_flag );
    Delay_ms ( 500 );
    
    // CIMI - request IMSI
    nbiot_send_cmd( &nbiot, NBIOT_CMD_CIMI );
    app_error_flag = nbiot_rsp_check(  );
    nbiot_error_check( app_error_flag );
    Delay_ms ( 500 );
    
    app_buf_len = 0;
    app_buf_cnt = 0;
    app_connection_status = WAIT_FOR_CONNECTION;
    log_info( &logger, " Application Task " );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
}

void application_task ( void )
{  
    if ( app_connection_status == WAIT_FOR_CONNECTION )
    {
        // CGATT - request IMSI
        nbiot_send_cmd_check( &nbiot, NBIOT_CMD_CGATT );
        app_error_flag = nbiot_rsp_check(  );
        nbiot_error_check( app_error_flag );
        Delay_ms ( 500 );
        
        // CEREG - network registration status
        nbiot_send_cmd_check( &nbiot, NBIOT_CMD_CEREG );
        app_error_flag = nbiot_rsp_check(  );
        nbiot_error_check( app_error_flag );
        Delay_ms ( 500 );
        
        // CSQ - signal quality
        nbiot_send_cmd( &nbiot, NBIOT_CMD_CSQ );
        app_error_flag = nbiot_rsp_check(  );
        nbiot_error_check( app_error_flag );
        Delay_ms ( 1000 );
        Delay_ms ( 1000 );
        Delay_ms ( 1000 );
        Delay_ms ( 1000 );
        Delay_ms ( 1000 );
    }
    else
    {
        log_info( &logger, "CONNECTED TO NETWORK" );
        
        log_info( &logger, "CHECKING SIGNAL QUALITY" );
        nbiot_send_cmd( &nbiot, NBIOT_CMD_CSQ );
        app_error_flag = nbiot_rsp_check(  );
        nbiot_error_check( app_error_flag );
        Delay_ms ( 1000 );
        Delay_ms ( 1000 );
        Delay_ms ( 1000 );
        Delay_ms ( 1000 );
        Delay_ms ( 1000 );
    }
}

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;
}

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

static err_t nbiot_process ( void )
{
    err_t return_flag = APP_ERROR_DRIVER;
    int32_t rx_size;
    char rx_buff[ PROCESS_BUFFER_SIZE ] = { 0 };
    
    rx_size = nbiot_generic_read( &nbiot, rx_buff, PROCESS_BUFFER_SIZE );

    if ( rx_size > 0 )
    { 
        int32_t buf_cnt = 0;
        return_flag = APP_OK;

        if ( app_buf_len + rx_size >= PROCESS_BUFFER_SIZE )
        {
            nbiot_clear_app_buf(  );
            return_flag = APP_ERROR_OVERFLOW;
        }
        else
        {
            buf_cnt = app_buf_len;
            app_buf_len += rx_size;
        }

        for ( int32_t rx_cnt = 0; rx_cnt < rx_size; rx_cnt++ )
        {
            if ( rx_buff[ rx_cnt ] != 0 ) 
            {
                app_buf[ ( buf_cnt + rx_cnt ) ] = rx_buff[ rx_cnt ];
            }
            else
            {
                app_buf_len--;
                buf_cnt--;
            }
        }
    } 

    return return_flag;
}

static err_t nbiot_rsp_check ( void )
{
    uint16_t timeout_cnt = 0;
    uint16_t timeout = 20000;
    
    err_t error_flag = nbiot_process(  );
    
    if ( ( error_flag != 0 ) && ( error_flag != -1 ) )
    {
        return error_flag;
    }
    
    while ( ( strstr( app_buf, RSP_OK ) == 0 ) && ( strstr( app_buf, RSP_ERROR ) == 0 ) )
    {
        error_flag = nbiot_process(  );
        if ( ( error_flag != 0 ) && ( error_flag != -1 ) )
        {
            return error_flag;
        }
        
        timeout_cnt++;
        if ( timeout_cnt > timeout )
        {
            while ( ( strstr( app_buf, RSP_OK ) == 0 ) && ( strstr( app_buf, RSP_ERROR ) == 0 ) )
            {
                nbiot_send_cmd( &nbiot, NBIOT_CMD_AT );
                nbiot_process(  );
                Delay_ms ( 100 );
            }
            nbiot_clear_app_buf(  );
            return APP_ERROR_TIMEOUT;
        }
        
        Delay_ms ( 1 );
    }
    
    nbiot_check_connection();
    
    nbiot_log_app_buf();
    
    log_printf( &logger, "-----------------------------------\r\n" );
    
    return APP_OK;
}

static void nbiot_error_check( err_t error_flag )
{
    if ( ( error_flag != 0 ) && ( error_flag != -1 ) )
    {
        switch ( error_flag )
        {
            case -2:
                log_error( &logger, " Overflow!" );
                break;
            case -3:
                log_error( &logger, " Timeout!" );
                break;
            default:
                break;
        }
    }
}

static void nbiot_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 ] );
    }
    log_printf( &logger, "\r\n" );
    nbiot_clear_app_buf(  );
}

static void nbiot_check_connection( void )
{
    #define CONNECTED "+CGATT:1"
    
    if ( strstr( app_buf, CONNECTED ) != 0 )
    {
        app_connection_status = CONNECTED_TO_NETWORK;
    }
}

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

Additional Support

Resources

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