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4G LTE 2 Click - Voice (for North America) with EasyAVR v7

Published Nov 01, 2023

Click board™

4G LTE 2 Click - Voice (for North America)

Dev.Board

EasyAVR v7

Compiler

NECTO Studio

MCU

ATmega1284P

Discover the next level of connectivity with our LTE Cat.1 multi-band solution – designed to seamlessly connect and securely elevate your business operations across North America.

A

A

Hardware Overview

How does it work?

4G LTE 2 Click - Voice (for North America) is based on the LARA-R6401, a multi-band and multi-mode module from LARA-R6 series from u-blox, supporting LTE Cat 1 FDD and LTE Cat 1 TDD radio access technology (18 LTE bands), with 3G UMTS/HSPA and 2G GSM/GPRS/EGPRS fallback providing the ideal solution for uncompromised connectivity for the North American market. This Click board™ represents a data and voice solution with global coverage and all relevant MNO certifications, offering great flexibility and the support of voice/audio applications. Versatile interfaces and features make the LARA-R6401 ideally suited for a wide range of applications that require medium data speed, seamless connectivity, superior coverage, low latency, and streaming data such as asset tracking, telematics, remote monitoring, point-of-sale terminals, and more. The LARA-R6401 module provides Voice over LTE (VoLTE) and Circuit-Switched-Fall-Back (CSFB) from LTE to 3G or 2G radio bearer for audio services users can access via an onboard 3.5mm audio jack. This audio interface is configurable through the AT commands to transfer digital audio data to/from an external device as an onboard audio codec. This module requires a

power supply of 3.8V. Therefore, the Click board™ incorporates an integrated buck (step-down DC-DC) converter, labeled as TPS7A7002 by Texas Instruments, which provides a stable 3.8V power supply, capable of mitigating voltage drops at the input when a high current peak appears (typically at the StartUp of the device). The module Ignition (Power-On) pin, labeled as PWR and routed to the RST pin on the mikroBUS™ socket, offers a switch operation to turn ON/OFF power delivery to the LARA-R6401. The LARA-R6401 communicates with MCU using the UART interface with commonly used UART RX and TX pins with the hardware flow control pins UART CTS, RTS, RI (Clear to Send, Ready to Send, and Ring Indicator). It operates at 115200 bps by default configuration to transmit and exchange data with the host MCU through AT commands that u-blox provides. Besides the UART interface, the LARA-R6401 also allows the I2C interface to act as an I2C host, which can communicate with I2C local devices following the I2C bus specifications. This Click board™ is also equipped with a USB type C connector, available for diagnostic purposes only. The module is a USB device and can be connected to any USB host with compatible drivers. Among its used

pins, this Click board™ also possesses two additional LED indicators: the yellow LED labeled as STATUS, routed both to the mikroBUS™ AN pin (STS) and the LED, used to indicate the status of the network connection visually, and a red LED labeled as TX used to tell the transmitting status of the module. The LTE cellular networks use spatial multiplexing antenna technology, allowing more than one antenna to be used for better reception of the specific frequency channel. For that reason, besides the primary TX/RX antenna, this Click board™ uses a secondary diversity RX antenna, which allows better signal reception. Alongside those SMA connectors, the 4G LTE 2 Click also has a Nano-SIM card slot that provides multiple connections and interface options alongside several test points labeled from TP1 to TP3, enabling easy reboot and testing of the module. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the VCC SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. Also, this Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used as a reference for further development.

4G LTE 2 Click - Voice (for North America) hardware overview image

Features overview

Development board

EasyAVR v7 is the seventh generation of AVR development boards specially designed for the needs of rapid development of embedded applications. It supports a wide range of 16-bit AVR microcontrollers from Microchip and has a broad set of unique functions, such as a powerful onboard mikroProg programmer and In-Circuit debugger over USB. The development board is well organized and designed so that the end-user has all the necessary elements in one place, such as switches, buttons, indicators, connectors, and others. With four different connectors for each port, EasyAVR v7 allows you to connect accessory boards, sensors, and custom electronics more

efficiently than ever. Each part of the EasyAVR v7 development board contains the components necessary for the most efficient operation of the same board. An integrated mikroProg, a fast USB 2.0 programmer with mikroICD hardware In-Circuit Debugger, offers many valuable programming/debugging options and seamless integration with the Mikroe software environment. Besides it also includes a clean and regulated power supply block for the development board. It can use a wide range of external power sources, including an external 12V power supply, 7-12V AC or 9-15V DC via DC connector/screw terminals, and a power source via the USB Type-B (USB-B)

connector. Communication options such as USB-UART and RS-232 are also included, alongside the well-established mikroBUS™ standard, three display options (7-segment, graphical, and character-based LCD), and several different DIP sockets which cover a wide range of 16-bit AVR MCUs. EasyAVR v7 is an integral part of the Mikroe ecosystem for rapid development. Natively supported by Mikroe software tools, it covers many aspects of prototyping and development thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.

EasyAVR v7 horizontal image

Microcontroller Overview

MCU Card / MCU

default

Architecture

AVR

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

40

RAM (Bytes)

16384

You complete me!

Accessories

This multiband LTE Rubber Antenna with adjustable angle is an excellent choice for all 3G/4G LTE-based click boards from our offer, as well as other devices that require excellent throughput on all major cellular bands worldwide. The antenna has an SMA male connector, which allows it to be mounted directly on the Click board™ or the female SMA module connector. The antenna position can be adjusted in 45⁰ increments (0⁰/45⁰/90⁰).

4G LTE 2 Click - Voice (for North America) accessories image

Used MCU Pins

mikroBUS™ mapper

Module Status
PA7
AN
Power-ON
PA6
RST
UART RTS
PA5
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
Ring Indicator
PD4
PWM
UART CTS
PD2
INT
UART TX
PD1
TX
UART RX
PD0
RX
I2C Clock
PC0
SCL
I2C Data
PC1
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Schematic

4G LTE 2 Click - Voice (for North America Schematic schematic

Step by step

Project assembly

EasyAVR v7 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyAVR v7 as your development board.

EasyAVR v7 front image hardware assembly
GNSS2 Click front image hardware assembly
MCU DIP 40 hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
EasyAVR v7 Access DIP 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 Compiler Selection Step Image hardware assembly
NECTO Output Selection Step Image hardware assembly
Necto image step 6 hardware assembly
Necto DIP image step 7 hardware assembly
EasyPIC PRO v7a Display Selection Necto Step hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Necto PreFlash Image hardware assembly

Track your results in real time

Application Output

After pressing the "FLASH" button on the left-side panel, it is necessary to open the UART terminal to display the achieved results. By clicking on the Tools icon in the right-hand panel, multiple different functions are displayed, among which is the UART Terminal. Click on the offered "UART Terminal" icon.

UART Application Output Step 1

Once the UART terminal is opened, the window takes on a new form. At the top of the tab are two buttons, one for adjusting the parameters of the UART terminal and the other for connecting the UART terminal. The tab's lower part is reserved for displaying the achieved results. Before connecting, the terminal has a Disconnected status, indicating that the terminal is not yet active. Before connecting, it is necessary to check the set parameters of the UART terminal. Click on the "OPTIONS" button.

UART Application Output Step 2

In the newly opened UART Terminal Options field, we check if the terminal settings are correct, such as the set port and the Baud rate of UART communication. If the data is not displayed properly, it is possible that the Baud rate value is not set correctly and needs to be adjusted to 115200. If all the parameters are set correctly, click on "CONFIGURE".

UART Application Output Step 3

The next step is to click on the "CONNECT" button, after which the terminal status changes from Disconnected to Connected in green, and the data is displayed in the Received data field.

UART Application Output Step 4

Software Support

Library Description

This library contains API for 4G LTE 2 Click - Voice (for US) driver.

Key functions:

  • c4glte2voicena_set_power_state - This function sets a desired power state by toggling PWR pin with a specific time for high state.

  • c4glte2voicena_set_sim_apn - This function sets APN for sim card.

  • c4glte2voicena_send_sms_text - This function sends text message to a phone number.

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 4G LTE 2 Voice-NA Click Example.
 *
 * # Description
 * Application example shows device capability of connecting to the network and
 * sending SMS or TCP/UDP messages using standard "AT" commands.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver, restarts the module and tests the communication.
 *
 * ## Application Task
 * Application task is split in few stages:
 *  - C4GLTE2VOICENA_CONFIGURE_FOR_NETWORK:
 * Sets configuration to device to be able to connect to the network.
 *
 *  - C4GLTE2VOICENA_WAIT_FOR_CONNECTION:
 * Waits for the network registration indicated via CREG URC event and then checks the connection status.
 *
 *  - C4GLTE2VOICENA_CONFIGURE_FOR_EXAMPLE:
 * Sets the device configuration for sending SMS or TCP/UDP messages depending on the selected demo example.
 *
 *  - C4GLTE2VOICENA_EXAMPLE:
 * Depending on the selected demo example, it sends an SMS message (in PDU or TXT mode) or TCP/UDP message.
 *
 * By default, the TCP/UDP example is selected.
 *
 * ## Additional Function
 * - static void c4glte2voicena_clear_app_buf ( void )
 * - static err_t c4glte2voicena_process ( void )
 * - static void c4glte2voicena_error_check( err_t error_flag )
 * - static void c4glte2voicena_log_app_buf ( void )
 * - static err_t c4glte2voicena_rsp_check ( void )
 * - static err_t c4glte2voicena_cfg_for_network( void )
 * - static err_t c4glte2voicena_check_connection( void )
 * - static err_t c4glte2voicena_cfg_for_example( void )
 * - static err_t c4glte2voicena_example( void )
 *
 * @note
 * In order for the examples to work, user needs to set the APN and SMSC (SMS PDU mode only)
 * of entered SIM card as well as the phone number (SMS mode only) to which he wants to send an SMS.
 * Enter valid values for the following macros: SIM_APN, SIM_SMSC and PHONE_NUMBER_TO_MESSAGE.
 * Example:
    SIM_APN "internet"
    SIM_SMSC "+381610401"
    PHONE_NUMBER_TO_MESSAGE "+381659999999"
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "c4glte2voicena.h"
#include "generic_pointer.h"
#include "conversions.h"

// Example selection macros
#define EXAMPLE_TCP_UDP                     0               // Example of sending messages to a TCP/UDP echo server
#define EXAMPLE_SMS                         1               // Example of sending SMS to a phone number
#define DEMO_EXAMPLE                        EXAMPLE_TCP_UDP // Example selection macro

// SIM APN config
#define SIM_APN                             "internet"      // Set valid SIM APN

// SMS example parameters
#define SIM_SMSC                            ""              // Set valid SMS Service Center Address - only in SMS PDU mode
#define PHONE_NUMBER_TO_MESSAGE             ""              // Set Phone number to message
#define SMS_MODE                            "1"             // SMS mode: "0" - PDU, "1" - TXT

// TCP/UDP example parameters
#define REMOTE_IP                           "77.46.162.162" // TCP/UDP echo server IP address
#define REMOTE_PORT                         "51111"         // TCP/UDP echo server port

// Message content
#define MESSAGE_CONTENT                     "4G LTE 2 Voice-NA click board - demo example."

// Application buffer size
#define PROCESS_BUFFER_SIZE                 300

/**
 * @brief Example states.
 * @details Predefined enum values for application example state.
 */
typedef enum
{
    C4GLTE2VOICENA_CONFIGURE_FOR_NETWORK = 1,
    C4GLTE2VOICENA_WAIT_FOR_CONNECTION,
    C4GLTE2VOICENA_CONFIGURE_FOR_EXAMPLE,
    C4GLTE2VOICENA_EXAMPLE

} c4glte2voicena_example_state_t;

static c4glte2voicena_t c4glte2voicena;
static log_t logger;

/**
 * @brief Application example variables.
 * @details Variables used in application example.
 */
static char app_buf[ PROCESS_BUFFER_SIZE ] = { 0 };
static int32_t app_buf_len = 0;
static int32_t app_buf_cnt = 0;
static err_t error_flag;
static c4glte2voicena_example_state_t example_state;

/**
 * @brief Clearing application buffer.
 * @details This function clears memory of application
 * buffer and reset its length and counter.
 */
static void c4glte2voicena_clear_app_buf ( void );

/**
 * @brief Data reading function.
 * @details This function reads data from device and
 * appends it to the application buffer.
 * @return @li @c  0 - Some data is read.
 *         @li @c -1 - Nothing is read.
 * See #err_t definition for detailed explanation.
 */
static err_t c4glte2voicena_process ( void );

/**
 * @brief Check for errors.
 * @details This function checks for different types of
 * errors and logs them on UART or logs the response if no errors occured.
 */
static void c4glte2voicena_error_check( err_t error_flag );

/**
 * @brief Logs application buffer.
 * @details This function logs data from application buffer.
 */
static void c4glte2voicena_log_app_buf ( void );

/**
 * @brief Response check.
 * @details This function checks for response and
 * returns the status of response.
 * @return @li @c  0 - OK response.
 *         @li @c -2 - Timeout error.
 *         @li @c -3 - Command error.
 *         @li @c -4 - Unknown error.
 * See #err_t definition for detailed explanation.
 */
static err_t c4glte2voicena_rsp_check ( void );

/**
 * @brief Configure device for connection to the network.
 * @details Sends commands to configure and enable
 * connection to the specified network.
 * @return @li @c  0 - OK response.
 *         @li @c -2 - Timeout error.
 *         @li @c -3 - Command error.
 *         @li @c -4 - Unknown error.
 * See #err_t definition for detailed explanation.
 */
static err_t c4glte2voicena_cfg_for_network( void );

/**
 * @brief Wait for connection signal.
 * @details Wait for connection signal from CREG URC.
 * @return @li @c  0 - OK response.
 *         @li @c -2 - Timeout error.
 *         @li @c -3 - Command error.
 *         @li @c -4 - Unknown error.
 * See #err_t definition for detailed explanation.
 */
static err_t c4glte2voicena_check_connection( void );

/**
 * @brief Configure device for example.
 * @details Configure device for the specified example.
 * @return @li @c  0 - OK response.
 *         @li @c -2 - Timeout error.
 *         @li @c -3 - Command error.
 *         @li @c -4 - Unknown error.
 * See #err_t definition for detailed explanation.
 */
static err_t c4glte2voicena_cfg_for_example( void );

/**
 * @brief Execute example.
 * @details This function executes SMS or TCP/UDP example depending on the DEMO_EXAMPLE macro.
 * @return @li @c  0 - OK response.
 *         @li @c -2 - Timeout error.
 *         @li @c -3 - Command error.
 *         @li @c -4 - Unknown error.
 * See #err_t definition for detailed explanation.
 */
static err_t c4glte2voicena_example( void );

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    c4glte2voicena_cfg_t c4glte2voicena_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.
    c4glte2voicena_cfg_setup( &c4glte2voicena_cfg );
    C4GLTE2VOICENA_MAP_MIKROBUS( c4glte2voicena_cfg, MIKROBUS_1 );
    if ( UART_ERROR == c4glte2voicena_init( &c4glte2voicena, &c4glte2voicena_cfg ) )
    {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );
        for ( ; ; );
    }
    c4glte2voicena_set_power_state ( &c4glte2voicena, C4GLTE2VOICENA_POWER_STATE_OFF );
    c4glte2voicena_set_power_state ( &c4glte2voicena, C4GLTE2VOICENA_POWER_STATE_ON );
    c4glte2voicena_process( );
    c4glte2voicena_clear_app_buf( );
    app_buf_len = 0;
    app_buf_cnt = 0;

    // Check communication
    c4glte2voicena_send_cmd( &c4glte2voicena, C4GLTE2VOICENA_CMD_AT );
    error_flag = c4glte2voicena_rsp_check( );
    c4glte2voicena_error_check( error_flag );

    log_info( &logger, " Application Task " );
    example_state = C4GLTE2VOICENA_CONFIGURE_FOR_NETWORK;
}

void application_task ( void )
{
    switch ( example_state )
    {
        case C4GLTE2VOICENA_CONFIGURE_FOR_NETWORK:
        {
            if ( C4GLTE2VOICENA_OK == c4glte2voicena_cfg_for_network( ) )
            {
                example_state = C4GLTE2VOICENA_WAIT_FOR_CONNECTION;
            }
            break;
        }
        case C4GLTE2VOICENA_WAIT_FOR_CONNECTION:
        {
            if ( C4GLTE2VOICENA_OK == c4glte2voicena_check_connection( ) )
            {
                example_state = C4GLTE2VOICENA_CONFIGURE_FOR_EXAMPLE;
            }
            break;
        }
        case C4GLTE2VOICENA_CONFIGURE_FOR_EXAMPLE:
        {
            if ( C4GLTE2VOICENA_OK == c4glte2voicena_cfg_for_example( ) )
            {
                example_state = C4GLTE2VOICENA_EXAMPLE;
            }
            break;
        }
        case C4GLTE2VOICENA_EXAMPLE:
        {
            c4glte2voicena_example( );
            break;
        }
        default:
        {
            log_error( &logger, " Example state." );
            break;
        }
    }
}

void main ( void )
{
    application_init( );

    for ( ; ; )
    {
        application_task( );
    }
}

static void c4glte2voicena_clear_app_buf ( void )
{
    memset( app_buf, 0, app_buf_len );
    app_buf_len = 0;
    app_buf_cnt = 0;
}

static err_t c4glte2voicena_process ( void )
{
    int32_t rx_size;
    char rx_buff[ PROCESS_BUFFER_SIZE ] = { 0 };
    rx_size = c4glte2voicena_generic_read( &c4glte2voicena, rx_buff, PROCESS_BUFFER_SIZE );
    if ( rx_size > 0 )
    {
        int32_t buf_cnt = 0;
        if ( ( app_buf_len + rx_size ) > PROCESS_BUFFER_SIZE )
        {
            c4glte2voicena_clear_app_buf(  );
            return C4GLTE2VOICENA_ERROR;
        }
        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 C4GLTE2VOICENA_OK;
    }
    return C4GLTE2VOICENA_ERROR;
}

static err_t c4glte2voicena_rsp_check ( void )
{
    uint32_t timeout_cnt = 0;
    uint32_t timeout = 120000;
    err_t error_flag = c4glte2voicena_process( );
    if ( ( C4GLTE2VOICENA_OK != error_flag ) && ( C4GLTE2VOICENA_ERROR != error_flag ) )
    {
        return error_flag;
    }
    while ( ( 0 == strstr( app_buf, C4GLTE2VOICENA_RSP_OK ) ) &&
            ( 0 == strstr( app_buf, C4GLTE2VOICENA_RSP_ERROR ) ) )
    {
        error_flag = c4glte2voicena_process( );
        if ( ( C4GLTE2VOICENA_OK != error_flag ) && ( C4GLTE2VOICENA_ERROR != error_flag ) )
        {
            return error_flag;
        }
        if ( timeout_cnt++ > timeout )
        {
            c4glte2voicena_clear_app_buf( );
            return C4GLTE2VOICENA_ERROR_TIMEOUT;
        }
        Delay_ms( 1 );
    }
    if ( strstr( app_buf, C4GLTE2VOICENA_RSP_OK ) )
    {
        return C4GLTE2VOICENA_OK;
    }
    else if ( strstr( app_buf, C4GLTE2VOICENA_RSP_ERROR ) )
    {
        return C4GLTE2VOICENA_ERROR_CMD;
    }
    else
    {
        return C4GLTE2VOICENA_ERROR_UNKNOWN;
    }
}

static void c4glte2voicena_error_check( err_t error_flag )
{
    switch ( error_flag )
    {
        case C4GLTE2VOICENA_OK:
        {
            c4glte2voicena_log_app_buf( );
            break;
        }
        case C4GLTE2VOICENA_ERROR:
        {
            log_error( &logger, " Overflow!" );
            break;
        }
        case C4GLTE2VOICENA_ERROR_TIMEOUT:
        {
            log_error( &logger, " Timeout!" );
            break;
        }
        case C4GLTE2VOICENA_ERROR_CMD:
        {
            log_error( &logger, " CMD!" );
            break;
        }
        case C4GLTE2VOICENA_ERROR_UNKNOWN:
        default:
        {
            log_error( &logger, " Unknown!" );
            break;
        }
    }
    c4glte2voicena_clear_app_buf(  );
    Delay_ms( 500 );
}

static void c4glte2voicena_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 err_t c4glte2voicena_cfg_for_network( void )
{
    err_t func_error = C4GLTE2VOICENA_OK;
    // Deregister from network
    #define DEREGISTER_FROM_NETWORK "2"
    c4glte2voicena_send_cmd_par( &c4glte2voicena, C4GLTE2VOICENA_CMD_COPS, DEREGISTER_FROM_NETWORK );
    error_flag = c4glte2voicena_rsp_check();
    func_error |= error_flag;
    c4glte2voicena_error_check( error_flag );
    
    // Set SIM APN
    c4glte2voicena_set_sim_apn( &c4glte2voicena, SIM_APN );
    error_flag = c4glte2voicena_rsp_check();
    func_error |= error_flag;
    c4glte2voicena_error_check( error_flag );

    // Enable full functionality
    #define FULL_FUNCTIONALITY "1"
    c4glte2voicena_send_cmd_par( &c4glte2voicena, C4GLTE2VOICENA_CMD_CFUN, FULL_FUNCTIONALITY );
    error_flag = c4glte2voicena_rsp_check();
    func_error |= error_flag;
    c4glte2voicena_error_check( error_flag );

    // Automatic registration
    #define AUTOMATIC_REGISTRATION "0"
    c4glte2voicena_send_cmd_par( &c4glte2voicena, C4GLTE2VOICENA_CMD_COPS, AUTOMATIC_REGISTRATION );
    error_flag = c4glte2voicena_rsp_check();
    func_error |= error_flag;
    c4glte2voicena_error_check( error_flag );

    // Enable network registartion
    #define ENABLE_REG "2"
    c4glte2voicena_send_cmd_par( &c4glte2voicena, C4GLTE2VOICENA_CMD_CREG, ENABLE_REG );
    error_flag = c4glte2voicena_rsp_check();
    func_error |= error_flag;
    c4glte2voicena_error_check( error_flag );
    return func_error;
}

static err_t c4glte2voicena_check_connection( void )
{
    #define CONNECTED "+CREG: 1"
    c4glte2voicena_process( );
    if ( strstr( app_buf, CONNECTED ) )
    {
        Delay_ms( 100 );
        c4glte2voicena_process( );
        c4glte2voicena_log_app_buf( );
        log_printf( &logger, "\r\n" );
        c4glte2voicena_clear_app_buf( );
        // Check signal quality
        c4glte2voicena_send_cmd( &c4glte2voicena, C4GLTE2VOICENA_CMD_CSQ );
        error_flag = c4glte2voicena_rsp_check( );
        c4glte2voicena_error_check( error_flag );
        return error_flag;
    }
    return C4GLTE2VOICENA_ERROR;
}

static err_t c4glte2voicena_cfg_for_example( void )
{
    err_t func_error = C4GLTE2VOICENA_OK;
#if ( DEMO_EXAMPLE == EXAMPLE_TCP_UDP )
    #define ACTIVATE_PDP_CONTEXT "1,1"
    c4glte2voicena_send_cmd_par( &c4glte2voicena, C4GLTE2VOICENA_CMD_CGACT, ACTIVATE_PDP_CONTEXT );
    error_flag = c4glte2voicena_rsp_check( );
    func_error |= error_flag;
    c4glte2voicena_error_check( error_flag );
#elif ( DEMO_EXAMPLE == EXAMPLE_SMS )
    c4glte2voicena_send_cmd_par( &c4glte2voicena, C4GLTE2VOICENA_CMD_CMGF, SMS_MODE );
    error_flag = c4glte2voicena_rsp_check( );
    func_error |= error_flag;
    c4glte2voicena_error_check( error_flag );
#else
    #error "No demo example selected"
#endif
    return func_error;
}

static err_t c4glte2voicena_example( void )
{
    err_t func_error = C4GLTE2VOICENA_OK;
#if ( DEMO_EXAMPLE == EXAMPLE_TCP_UDP )
    char cmd_buf[ 100 ] = { 0 };
    char urc_buf[ 20 ] = { 0 };
    uint16_t timeout_cnt = 0;
    uint16_t timeout = 30000;
    uint8_t * __generic_ptr socket_num_buf = 0;
    uint8_t tcp_socket_num[ 2 ] = { 0 };
    uint8_t udp_socket_num[ 2 ] = { 0 };

    // Create TCP socket
    #define RSP_USOCR "+USOCR: "
    #define TCP_PROTOCOL "6"
    c4glte2voicena_send_cmd_par( &c4glte2voicena, C4GLTE2VOICENA_CMD_USOCR, TCP_PROTOCOL );
    error_flag = c4glte2voicena_rsp_check( );
    func_error |= error_flag;
    socket_num_buf = strstr( app_buf, RSP_USOCR ) + strlen ( RSP_USOCR );
    tcp_socket_num[ 0 ] = *socket_num_buf;
    c4glte2voicena_error_check( error_flag );

    // Create UDP socket
    #define UDP_PROTOCOL "17"
    c4glte2voicena_send_cmd_par( &c4glte2voicena, C4GLTE2VOICENA_CMD_USOCR, UDP_PROTOCOL );
    error_flag = c4glte2voicena_rsp_check( );
    func_error |= error_flag;
    socket_num_buf = strstr( app_buf, RSP_USOCR ) + strlen ( RSP_USOCR );
    udp_socket_num[ 0 ] = *socket_num_buf;
    c4glte2voicena_error_check( error_flag );

    // Connect TCP socket to remote IP and port
    strcpy( cmd_buf, tcp_socket_num );
    strcat( cmd_buf, ",\"" );
    strcat( cmd_buf, REMOTE_IP );
    strcat( cmd_buf, "\"," );
    strcat( cmd_buf, REMOTE_PORT );
    c4glte2voicena_send_cmd_par( &c4glte2voicena, C4GLTE2VOICENA_CMD_USOCO, cmd_buf );
    error_flag = c4glte2voicena_rsp_check( );
    func_error |= error_flag;
    c4glte2voicena_error_check( error_flag );

    // Connect UDP socket to remote IP and port
    strcpy( cmd_buf, udp_socket_num );
    strcat( cmd_buf, ",\"" );
    strcat( cmd_buf, REMOTE_IP );
    strcat( cmd_buf, "\"," );
    strcat( cmd_buf, REMOTE_PORT );
    c4glte2voicena_send_cmd_par( &c4glte2voicena, C4GLTE2VOICENA_CMD_USOCO, cmd_buf );
    error_flag = c4glte2voicena_rsp_check( );
    func_error |= error_flag;
    c4glte2voicena_error_check( error_flag );

    // Get message length
    uint8_t message_len_buf[ 5 ] = { 0 };
    uint16_t message_len = strlen( MESSAGE_CONTENT );
    uint16_to_str( message_len, message_len_buf );
    l_trim( message_len_buf );
    r_trim( message_len_buf );

    // Write message to TCP socket
    strcpy( cmd_buf, tcp_socket_num );
    strcat( cmd_buf, "," );
    strcat( cmd_buf, message_len_buf );
    strcat( cmd_buf, ",\"" );
    strcat( cmd_buf, MESSAGE_CONTENT );
    strcat( cmd_buf, "\"" );
    c4glte2voicena_send_cmd_par( &c4glte2voicena, C4GLTE2VOICENA_CMD_USOWR, cmd_buf );
    error_flag = c4glte2voicena_rsp_check( );
    func_error |= error_flag;
    c4glte2voicena_error_check( error_flag );

    // Read response message from TCP socket
    #define URC_READ_SOCKET_DATA_TCP "+UUSORD: "
    strcpy( urc_buf, URC_READ_SOCKET_DATA_TCP );
    strcat( urc_buf, tcp_socket_num );
    for ( ; ; )
    {
        c4glte2voicena_process( );
        uint8_t * __generic_ptr start_response_buf = strstr( app_buf, urc_buf );
        if ( start_response_buf )
        {
            Delay_ms( 100 );
            c4glte2voicena_process( );
            uint8_t response_len_buf[ 5 ] = { 0 };
            char * __generic_ptr start_response_len = strstr( start_response_buf, "," ) + 1;
            memcpy ( response_len_buf, start_response_len, app_buf_len - ( start_response_len - app_buf ) );
            strcpy( cmd_buf, tcp_socket_num );
            strcat( cmd_buf, "," );
            strcat( cmd_buf, response_len_buf );
            c4glte2voicena_log_app_buf( );
            c4glte2voicena_clear_app_buf( );
            c4glte2voicena_send_cmd_par( &c4glte2voicena, C4GLTE2VOICENA_CMD_USORD, cmd_buf );
            error_flag = c4glte2voicena_rsp_check( );
            func_error |= error_flag;
            c4glte2voicena_error_check( error_flag );
            break;
        }
        if ( timeout_cnt++ > timeout )
        {
            break;
        }
        Delay_ms( 1 );
    }
    timeout_cnt = 0;

    // Write message to UDP socket
    strcpy( cmd_buf, udp_socket_num );
    strcat( cmd_buf, "," );
    strcat( cmd_buf, message_len_buf );
    strcat( cmd_buf, ",\"" );
    strcat( cmd_buf, MESSAGE_CONTENT );
    strcat( cmd_buf, "\"" );
    c4glte2voicena_send_cmd_par( &c4glte2voicena, C4GLTE2VOICENA_CMD_USOWR, cmd_buf );
    error_flag = c4glte2voicena_rsp_check( );
    func_error |= error_flag;
    c4glte2voicena_error_check( error_flag );

    // Read response message from UDP socket
    #define URC_READ_SOCKET_DATA_UDP "+UUSORD: "
    strcpy( urc_buf, URC_READ_SOCKET_DATA_UDP );
    strcat( urc_buf, udp_socket_num );
    for ( ; ; )
    {
        c4glte2voicena_process( );
        uint8_t * __generic_ptr start_response_buf = strstr( app_buf, urc_buf );
        if ( start_response_buf )
        {
            Delay_ms( 100 );
            c4glte2voicena_process( );
            uint8_t response_len_buf[ 5 ] = { 0 };
            char * __generic_ptr start_response_len = strstr( start_response_buf, "," ) + 1;
            memcpy ( response_len_buf, start_response_len, app_buf_len - ( start_response_len - app_buf ) );
            strcpy( cmd_buf, udp_socket_num );
            strcat( cmd_buf, "," );
            strcat( cmd_buf, response_len_buf );
            c4glte2voicena_log_app_buf( );
            c4glte2voicena_clear_app_buf( );
            c4glte2voicena_send_cmd_par( &c4glte2voicena, C4GLTE2VOICENA_CMD_USORD, cmd_buf );
            error_flag = c4glte2voicena_rsp_check( );
            func_error |= error_flag;
            c4glte2voicena_error_check( error_flag );
            break;
        }
        if ( timeout_cnt++ > timeout )
        {
            break;
        }
        Delay_ms( 1 );
    }
    
    // Close TCP socket
    c4glte2voicena_send_cmd_par( &c4glte2voicena, C4GLTE2VOICENA_CMD_USOCL, tcp_socket_num );
    error_flag = c4glte2voicena_rsp_check( );
    func_error |= error_flag;
    c4glte2voicena_error_check( error_flag );
    
    // Close UDP socket
    c4glte2voicena_send_cmd_par( &c4glte2voicena, C4GLTE2VOICENA_CMD_USOCL, udp_socket_num );
    error_flag = c4glte2voicena_rsp_check( );
    func_error |= error_flag;
    c4glte2voicena_error_check( error_flag );
    Delay_ms( 5000 );
#elif ( DEMO_EXAMPLE == EXAMPLE_SMS )
    // Check SMS mode
    #define CMGF_PDU "+CMGF: 0"
    #define CMGF_TXT "+CMGF: 1"
    c4glte2voicena_send_cmd_check( &c4glte2voicena, C4GLTE2VOICENA_CMD_CMGF );
    error_flag = c4glte2voicena_rsp_check( );
    func_error |= error_flag;
    if ( strstr( app_buf, CMGF_PDU ) )
    {
        c4glte2voicena_error_check( error_flag );
        // Send SMS in PDU mode
        c4glte2voicena_send_sms_pdu( &c4glte2voicena, SIM_SMSC, PHONE_NUMBER_TO_MESSAGE, MESSAGE_CONTENT );
        error_flag = c4glte2voicena_rsp_check( );
        func_error |= error_flag;
    }
    else if ( strstr( app_buf, CMGF_TXT ) )
    {
        c4glte2voicena_error_check( error_flag );
        // Send SMS in TXT mode
        c4glte2voicena_send_sms_text ( &c4glte2voicena, PHONE_NUMBER_TO_MESSAGE, MESSAGE_CONTENT );
        error_flag = c4glte2voicena_rsp_check( );
        func_error |= error_flag;
    }
    c4glte2voicena_error_check( error_flag );
    Delay_ms( 10000 );
    Delay_ms( 10000 );
    Delay_ms( 10000 );
#else
    #error "No demo example selected"
#endif
    return func_error;
}

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

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