Intermediate
20 min

Experience the future of communication with SARA U-201 and PIC18F57Q43

Your gateway to ultimate cellular networking!

3G SARA Click with Curiosity Nano with PIC18F57Q43

Published Feb 13, 2024

Click board™

3G SARA Click

Dev Board

Curiosity Nano with PIC18F57Q43

Compiler

NECTO Studio

MCU

PIC18F57Q43

Step into a world of possibilities with our cellular network communication solution, offering everything you need, from network indication to a complete TCP/UDP stack and advanced HTTP/HTTPS transfer capabilities, ensuring unparalleled connectivity and communication efficiency

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Hardware Overview

How does it work?

3G SARA Click is based on the SARA U-201, a compact 3.75G UMTS/HSPA modem from u-blox. The SARA U-201 module can be used worldwide. A complete list of frequencies and other relevant info about the module can be found in the SARA U-201 datasheet. This device is the main component of the click board, and it consists of several internal blocks or sections, such as the antenna switching section, RF transceiver section, memory, power management, and, most importantly - the cellular baseband processor. This section contains the logic necessary for managing the other sections and provides the interface to the host MCU. This interface consists of several lines that report the antenna status, SIM card status, SIM card interface lines, GPIOs, UART interface lines, USB interface lines, I2C bus lines, device control lines, and I2S bus lines. These lines are routed to the respective elements of the click board. The SARA U-201 module has to be powered by a clean and stable power supply. The voltage needed for the module to work properly is about 4V, and it is derived from the 5V mikroBUS™ rail through the MCP1826, a 1A low drop output (LDO) regulator from Microchip. Although the SARA U-201 is a low-power device, the cellular network modules, in general, are notorious for their high power consumption, so the 1A LDO had to be used. Digital sections of the SARA U-201 are internally supplied by 1.8V, so it is necessary to condition the communication bus lines that

connect the host MCU with the module. For this reason, another small LDO is used, providing a needed reference voltage for one side of the TXB0106, a 6-bit bidirectional level shifting and voltage translator with automatic direction sensing from Texas Instruments. The reference voltage for the other side of the level shifter is taken from the onboard SMD jumper, labeled as PWR SEL. This jumper selects between 3.3V and 5V from the mikroBUS™, depending on the used MCU type and its logic voltage level requirements. The UART bus of the SARA U-201 module is connected to one side of the level shifter, while the other side (shifted) is connected to the respective mikroBUS™ UART pins. However, the  SARA U-201 module is designed as the traditional DCE device (Data Communication Equipment), offering the full UART pin count, including the hardware flow control pins (CTS, RTS). These pins are routed to the mikroBUS™ CS (RTS) and the INT pin (CTS) and can be used in the MCU software if the hardware flow control is needed. The RI pin is the ringing indicator routed to the mikroBUS™ PWM pin. The STAT pin is used to signal the network connection status. This pin is routed to the mikroBUS™ AN pin through the level shifter, and the yellow LED is used to indicate the network connection's status visually. The transmitting status is indicated by the red TX LED next to the STAT LED. The PWRKEY pin is routed to the mikroBUS™ RST pin and used during the

power-up sequence. A low pulse on this pin will power the device if a valid supply voltage is provided. To properly detach from the network and store the working parameters in its non-volatile memory, the module should be safely powered off either by issuing the AT+CPWROFF command or by a low pulse on the PWRKEY pin for at least 1 second before disconnecting the power source. As mentioned, SARA U-201 offers the I2S interface, mainly used for digital audio. The MAX9860, a 16-bit mono audio voice CODEC IC from Maxim Integrated, provides the 3G SARA click board with voice communication. This IC uses the I2S and I2C interfaces to communicate with the SARA U-201 module. It is also powered with 1.8V from the LDO, so no level shifting is required. This IC provides a clean and audible analog interface for connecting the headset, with one audio output channel and one microphone input channel. The headset can be connected via the onboard 3.5mm audio jack. SARA 3G click is equipped with a micro USB connector. It allows the module to be powered and configured by a personal computer (PC). u-blox company offers a software suite that can be used to configure the SARA U-201 module. The Micro SIM card holder on the back of the click board™ is used to install a SIM card. This device can not be used without a valid SIM card, which allows connection to the cellular network. Both 1.8V and 3V SIM card types are supported.

3G SARA Click hardware overview image

Features overview

Development board

PIC18F57Q43 Curiosity Nano evaluation kit is a cutting-edge hardware platform designed to evaluate microcontrollers within the PIC18-Q43 family. Central to its design is the inclusion of the powerful PIC18F57Q43 microcontroller (MCU), offering advanced functionalities and robust performance. Key features of this evaluation kit include a yellow user LED and a responsive

mechanical user switch, providing seamless interaction and testing. The provision for a 32.768kHz crystal footprint ensures precision timing capabilities. With an onboard debugger boasting a green power and status LED, programming and debugging become intuitive and efficient. Further enhancing its utility is the Virtual serial port (CDC) and a debug GPIO channel (DGI

GPIO), offering extensive connectivity options. Powered via USB, this kit boasts an adjustable target voltage feature facilitated by the MIC5353 LDO regulator, ensuring stable operation with an output voltage ranging from 1.8V to 5.1V, with a maximum output current of 500mA, subject to ambient temperature and voltage constraints.

PIC18F57Q43 Curiosity Nano double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

48

RAM (Bytes)

8196

You complete me!

Accessories

Curiosity Nano Base for Click boards is a versatile hardware extension platform created to streamline the integration between Curiosity Nano kits and extension boards, tailored explicitly for the mikroBUS™-standardized Click boards and Xplained Pro extension boards. This innovative base board (shield) offers seamless connectivity and expansion possibilities, simplifying experimentation and development. Key features include USB power compatibility from the Curiosity Nano kit, alongside an alternative external power input option for enhanced flexibility. The onboard Li-Ion/LiPo charger and management circuit ensure smooth operation for battery-powered applications, simplifying usage and management. Moreover, the base incorporates a fixed 3.3V PSU dedicated to target and mikroBUS™ power rails, alongside a fixed 5.0V boost converter catering to 5V power rails of mikroBUS™ sockets, providing stable power delivery for various connected devices.

Curiosity Nano Base for Click boards accessories 1 image

Rubber Antenna GSM/GPRS Right Angle is the perfect companion for all GSM Click boards™ in our extensive lineup. This specialized antenna is designed to optimize your wireless connectivity with impressive features. With a wide frequency range spanning 824-894/1710-1990MHz or 890-960/1710-1890MHz, it can handle various frequency bands, ensuring a seamless and reliable connection. The antenna boasts an impedance of 50 Ohms and a gain of 2dB, enhancing signal reception and transmission. Its 70/180MHz bandwidth provides flexibility for diverse applications. The vertical polarization further enhances its performance. With a maximum input power capacity of 50W, this antenna ensures robust communication even under demanding conditions. Measuring a compact 50mm in length and featuring an SMA male connector, the Rubber Antenna GSM/GPRS Right Angle is a versatile and compact solution for your wireless communication needs.

3G SARA Click accessories image

Used MCU Pins

mikroBUS™ mapper

Network Status
PA0
AN
PowerKey
PA7
RST
UART RTS
PD4
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
UART RI
PB0
PWM
UART CTS
PA6
INT
UART TX
PC3
TX
UART RX
PC2
RX
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Schematic

3G SARA Click Schematic schematic

Step by step

Project assembly

Curiosity Nano Base for Click boards front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Curiosity Nano with PIC18F57Q43 as your development board.

Curiosity Nano Base for Click boards front image hardware assembly
Charger 27 Click front image hardware assembly
PIC18F47Q10 Curiosity Nano front image hardware assembly
Prog-cut hardware assembly
Charger 27 Click complete accessories setup image hardware assembly
Curiosity Nano with PICXXX 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
PIC18F57Q43 Curiosity 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 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.

DEBUG_Application_Output

Software Support

Library Description

This library contains API for 3G SARA Click driver.

Key functions:

  • c3gsara_set_sim_apn - This function sets APN for sim card

  • c3gsara_send_sms_text - This function sends text message to a phone number

  • c3gsara_send_sms_pdu - This function sends text message to a phone number in PDU mode

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 3G SARA 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, tests the communication by sending "AT" command, and after that restarts the device.
 *
 * ## Application Task
 * Application task is split in few stages:
 *  - C3GSARA_CONFIGURE_FOR_NETWORK:
 * Sets configuration to device to be able to connect to the network.
 *
 *  - C3GSARA_WAIT_FOR_CONNECTION:
 * Waits for the network registration indicated via CREG URC event and then checks
 * the connection status.
 *
 *  - C3GSARA_CONFIGURE_FOR_EXAMPLE:
 * Sets the device configuration for sending SMS or TCP/UDP messages depending on the selected demo example.
 *
 *  - C3GSARA_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 c3gsara_clear_app_buf ( void )
 * - static err_t c3gsara_process ( void )
 * - static void c3gsara_error_check( err_t error_flag )
 * - static void c3gsara_log_app_buf ( void )
 * - static err_t c3gsara_rsp_check ( uint8_t *rsp )
 * - static err_t c3gsara_configure_for_connection( void )
 * - static err_t c3gsara_check_connection( void )
 * - static err_t c3gsara_configure_for_messages( void )
 * - static err_t c3gsara_send_message( 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 "c3gsara.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                             ""              // 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                     "3G SARA click board - demo example."

// Application buffer size
#define APP_BUFFER_SIZE                     256
#define PROCESS_BUFFER_SIZE                 256

/**
 * @brief Example states.
 * @details Predefined enum values for application example state.
 */
typedef enum
{
    C3GSARA_CONFIGURE_FOR_NETWORK = 1,
    C3GSARA_WAIT_FOR_CONNECTION,
    C3GSARA_CONFIGURE_FOR_EXAMPLE,
    C3GSARA_EXAMPLE

} c3gsara_example_state_t;

static c3gsara_t c3gsara;
static log_t logger;

/**
 * @brief Application example variables.
 * @details Variables used in application example.
 */
static uint8_t app_buf[ APP_BUFFER_SIZE ] = { 0 };
static int32_t app_buf_len = 0;
static err_t error_flag;
static c3gsara_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 c3gsara_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 c3gsara_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.
 * @param[in] error_flag  Error flag to check.
 */
static void c3gsara_error_check ( err_t error_flag );

/**
 * @brief Logs application buffer.
 * @details This function logs data from application buffer.
 */
static void c3gsara_log_app_buf ( void );

/**
 * @brief Response check.
 * @details This function checks for response and
 * returns the status of response.
 * @param[in] rsp  Expected 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 c3gsara_rsp_check ( uint8_t *rsp );

/**
 * @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 c3gsara_configure_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 c3gsara_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 c3gsara_configure_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 c3gsara_example ( void );

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    c3gsara_cfg_t c3gsara_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.
    c3gsara_cfg_setup( &c3gsara_cfg );
    C3GSARA_MAP_MIKROBUS( c3gsara_cfg, MIKROBUS_1 );
    if ( UART_ERROR == c3gsara_init( &c3gsara, &c3gsara_cfg ) )
    {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );
        for ( ; ; );
    }
    
    c3gsara_set_power_state ( &c3gsara, C3GSARA_POWER_STATE_ON );
    
    c3gsara_process( );
    c3gsara_clear_app_buf( );

    // Check communication
    c3gsara_send_cmd( &c3gsara, C3GSARA_CMD_AT );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    c3gsara_error_check( error_flag );
    
    // Restart device
    #define RESTART_DEVICE "1,1"
    c3gsara_send_cmd_with_par( &c3gsara, C3GSARA_CMD_CFUN, RESTART_DEVICE );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    c3gsara_error_check( error_flag );
    
    log_info( &logger, " Application Task " );
    example_state = C3GSARA_CONFIGURE_FOR_NETWORK;
}

void application_task ( void )
{
    switch ( example_state )
    {
        case C3GSARA_CONFIGURE_FOR_NETWORK:
        {
            if ( C3GSARA_OK == c3gsara_configure_for_network( ) )
            {
                example_state = C3GSARA_WAIT_FOR_CONNECTION;
            }
            break;
        }
        case C3GSARA_WAIT_FOR_CONNECTION:
        {
            if ( C3GSARA_OK == c3gsara_check_connection( ) )
            {
                example_state = C3GSARA_CONFIGURE_FOR_EXAMPLE;
            }
            break;
        }
        case C3GSARA_CONFIGURE_FOR_EXAMPLE:
        {
            if ( C3GSARA_OK == c3gsara_configure_for_example( ) )
            {
                example_state = C3GSARA_EXAMPLE;
            }
            break;
        }
        case C3GSARA_EXAMPLE:
        {
            c3gsara_example( );
            break;
        }
        default:
        {
            log_error( &logger, " Example state." );
            break;
        }
    }
}

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 c3gsara_clear_app_buf ( void )
{
    memset( app_buf, 0, app_buf_len );
    app_buf_len = 0;
}

static err_t c3gsara_process ( void )
{
    uint8_t rx_buf[ PROCESS_BUFFER_SIZE ] = { 0 };
    int32_t rx_size = 0;
    rx_size = c3gsara_generic_read( &c3gsara, rx_buf, PROCESS_BUFFER_SIZE );
    if ( rx_size > 0 ) 
    {
        int32_t buf_cnt = app_buf_len;
        if ( ( ( app_buf_len + rx_size ) > APP_BUFFER_SIZE ) && ( app_buf_len > 0 ) ) 
        {
            buf_cnt = APP_BUFFER_SIZE - ( ( app_buf_len + rx_size ) - APP_BUFFER_SIZE );
            memmove ( app_buf, &app_buf[ APP_BUFFER_SIZE - buf_cnt ], buf_cnt );
        }
        for ( int32_t rx_cnt = 0; rx_cnt < rx_size; rx_cnt++ ) 
        {
            if ( rx_buf[ rx_cnt ] ) 
            {
                app_buf[ buf_cnt++ ] = rx_buf[ rx_cnt ];
                if ( app_buf_len < APP_BUFFER_SIZE )
                {
                    app_buf_len++;
                }
            }
        }
        return C3GSARA_OK;
    }
    return C3GSARA_ERROR;
}

static err_t c3gsara_rsp_check ( uint8_t *rsp )
{
    uint32_t timeout_cnt = 0;
    uint32_t timeout = 120000;
    c3gsara_clear_app_buf( );
    c3gsara_process( );
    while ( ( 0 == strstr( app_buf, rsp ) ) &&
            ( 0 == strstr( app_buf, C3GSARA_RSP_ERROR ) ) )
    {
        c3gsara_process( );
        if ( timeout_cnt++ > timeout )
        {
            c3gsara_clear_app_buf( );
            return C3GSARA_ERROR_TIMEOUT;
        }
        Delay_ms ( 1 );
    }
    Delay_ms ( 100 );
    c3gsara_process( );
    if ( strstr( app_buf, rsp ) )
    {
        return C3GSARA_OK;
    }
    else if ( strstr( app_buf, C3GSARA_RSP_ERROR ) )
    {
        return C3GSARA_ERROR_CMD;
    }
    else
    {
        return C3GSARA_ERROR_UNKNOWN;
    }
}

static void c3gsara_error_check ( err_t error_flag )
{
    switch ( error_flag )
    {
        case C3GSARA_OK:
        {
            c3gsara_log_app_buf( );
            break;
        }
        case C3GSARA_ERROR:
        {
            log_error( &logger, " Overflow!" );
            break;
        }
        case C3GSARA_ERROR_TIMEOUT:
        {
            log_error( &logger, " Timeout!" );
            break;
        }
        case C3GSARA_ERROR_CMD:
        {
            log_error( &logger, " CMD!" );
            break;
        }
        case C3GSARA_ERROR_UNKNOWN:
        default:
        {
            log_error( &logger, " Unknown!" );
            break;
        }
    }
    Delay_ms ( 500 );
}

static void c3gsara_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 c3gsara_configure_for_network ( void )
{
    err_t func_error = C3GSARA_OK;
#if ( ( DEMO_EXAMPLE == EXAMPLE_TCP_UDP ) || ( DEMO_EXAMPLE == EXAMPLE_SMS ) )
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    // Deregister from network
    #define DEREGISTER_FROM_NETWORK "2"
    c3gsara_send_cmd_with_par( &c3gsara, C3GSARA_CMD_COPS, DEREGISTER_FROM_NETWORK );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_error_check( error_flag );
    
    // Set SIM APN
    c3gsara_set_sim_apn( &c3gsara, SIM_APN );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_error_check( error_flag );

    // Enable full functionality
    #define FULL_FUNCTIONALITY "1"
    c3gsara_send_cmd_with_par( &c3gsara, C3GSARA_CMD_CFUN, FULL_FUNCTIONALITY );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_error_check( error_flag );

    // Enable network registartion
    #define ENABLE_REG "2"
    c3gsara_send_cmd_with_par( &c3gsara, C3GSARA_CMD_CREG, ENABLE_REG );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_error_check( error_flag );
    
    // Automatic registration
    #define AUTOMATIC_REGISTRATION "0"
    c3gsara_send_cmd_with_par( &c3gsara, C3GSARA_CMD_COPS, AUTOMATIC_REGISTRATION );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_error_check( error_flag );
#endif
    return func_error;
}

static err_t c3gsara_check_connection ( void )
{
#if ( ( DEMO_EXAMPLE == EXAMPLE_TCP_UDP ) || ( DEMO_EXAMPLE == EXAMPLE_SMS ) )
    #define CONNECTED "+CREG: 2,1"
    c3gsara_send_cmd_check ( &c3gsara, C3GSARA_CMD_CREG );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    c3gsara_error_check( error_flag );
    if ( strstr( app_buf, CONNECTED ) )
    {
        Delay_ms ( 100 );
        c3gsara_process( );
        c3gsara_log_app_buf( );
        log_printf( &logger, "\r\n" );
        c3gsara_clear_app_buf( );
        // Check signal quality
        c3gsara_send_cmd( &c3gsara, C3GSARA_CMD_CSQ );
        error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
        c3gsara_error_check( error_flag );
        return error_flag;
    }
    Delay_ms ( 1000 );
    return C3GSARA_ERROR;
#endif
    return C3GSARA_OK;
}

static err_t c3gsara_configure_for_example ( void )
{
    err_t func_error = C3GSARA_OK;
#if ( DEMO_EXAMPLE == EXAMPLE_TCP_UDP )
    #define ACTIVATE_PDP_CONTEXT "1,1"
    c3gsara_send_cmd_with_par( &c3gsara, C3GSARA_CMD_CGACT, ACTIVATE_PDP_CONTEXT );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_error_check( error_flag );
    #define ACTIVATE_PDP_PROFILE "1,3"
    c3gsara_send_cmd_with_par( &c3gsara, C3GSARA_CMD_UPSDA, ACTIVATE_PDP_PROFILE );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_error_check( error_flag );
#elif ( DEMO_EXAMPLE == EXAMPLE_SMS )
    c3gsara_send_cmd_with_par( &c3gsara, C3GSARA_CMD_CMGF, SMS_MODE );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_error_check( error_flag );
#else
    #error "No demo example selected"
#endif
    return func_error;
}

static err_t c3gsara_example ( void )
{
    err_t func_error = C3GSARA_OK;
#if ( DEMO_EXAMPLE == EXAMPLE_TCP_UDP )
    uint8_t cmd_buf[ 100 ] = { 0 };
    uint8_t 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"
    c3gsara_send_cmd_with_par ( &c3gsara, C3GSARA_CMD_USOCR, TCP_PROTOCOL );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    socket_num_buf = strstr( app_buf, RSP_USOCR ) + strlen ( RSP_USOCR );
    tcp_socket_num[ 0 ] = *socket_num_buf;
    c3gsara_error_check( error_flag );

    // Create UDP socket
    #define UDP_PROTOCOL "17"
    c3gsara_send_cmd_with_par ( &c3gsara, C3GSARA_CMD_USOCR, UDP_PROTOCOL );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    socket_num_buf = strstr( app_buf, RSP_USOCR ) + strlen ( RSP_USOCR );
    udp_socket_num[ 0 ] = *socket_num_buf;
    c3gsara_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 );
    c3gsara_send_cmd_with_par( &c3gsara, C3GSARA_CMD_USOCO, cmd_buf );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_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 );
    c3gsara_send_cmd_with_par ( &c3gsara, C3GSARA_CMD_USOCO, cmd_buf );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_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, "\"" );
    c3gsara_send_cmd_with_par ( &c3gsara, C3GSARA_CMD_USOWR, cmd_buf );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_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 ( ; ; )
    {
        c3gsara_process( );
        uint8_t * __generic_ptr start_response_buf = strstr( app_buf, urc_buf );
        if ( start_response_buf )
        {
            Delay_ms ( 100 );
            c3gsara_process( );
            uint8_t response_len_buf[ 5 ] = { 0 };
            uint8_t * __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 );
            c3gsara_log_app_buf( );
            c3gsara_clear_app_buf( );
            c3gsara_send_cmd_with_par ( &c3gsara, C3GSARA_CMD_USORD, cmd_buf );
            error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
            func_error |= error_flag;
            c3gsara_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, "\"" );
    c3gsara_send_cmd_with_par( &c3gsara, C3GSARA_CMD_USOWR, cmd_buf );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_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 ( ; ; )
    {
        c3gsara_process( );
        uint8_t * __generic_ptr start_response_buf = strstr( app_buf, urc_buf );
        if ( start_response_buf )
        {
            Delay_ms ( 100 );
            c3gsara_process( );
            uint8_t response_len_buf[ 5 ] = { 0 };
            uint8_t * __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 );
            c3gsara_log_app_buf( );
            c3gsara_clear_app_buf( );
            c3gsara_send_cmd_with_par ( &c3gsara, C3GSARA_CMD_USORF, cmd_buf );
            error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
            func_error |= error_flag;
            c3gsara_error_check( error_flag );
            break;
        }
        if ( timeout_cnt++ > timeout )
        {
            break;
        }
        Delay_ms ( 1 );
    }
    
    // Close TCP socket
    c3gsara_send_cmd_with_par ( &c3gsara, C3GSARA_CMD_USOCL, tcp_socket_num );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_error_check( error_flag );
    
    // Close UDP socket
    c3gsara_send_cmd_with_par ( &c3gsara, C3GSARA_CMD_USOCL, udp_socket_num );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_error_check( error_flag );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
#elif ( DEMO_EXAMPLE == EXAMPLE_SMS )
    // Check SMS mode
    #define CMGF_PDU "+CMGF: 0"
    #define CMGF_TXT "+CMGF: 1"
    c3gsara_send_cmd_check( &c3gsara, C3GSARA_CMD_CMGF );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_error_check( error_flag );
    if ( strstr( app_buf, CMGF_PDU ) )
    {
        // Send SMS in PDU mode
        c3gsara_send_sms_pdu( &c3gsara, SIM_SMSC, PHONE_NUMBER_TO_MESSAGE, MESSAGE_CONTENT );
        error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
        func_error |= error_flag;
        c3gsara_error_check( error_flag );
    }
    else if ( strstr( app_buf, CMGF_TXT ) )
    {
        // Send SMS in TXT mode
        c3gsara_send_sms_text ( &c3gsara, PHONE_NUMBER_TO_MESSAGE, MESSAGE_CONTENT );
        error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
        func_error |= error_flag;
        c3gsara_error_check( error_flag );
    }
    // 30 seconds delay
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
#else
    #error "No demo example selected"
#endif
    return func_error;
}

// ------------------------------------------------------------------------ END
/*!
 * @file main.c
 * @brief 3G SARA 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, tests the communication by sending "AT" command, and after that restarts the device.
 *
 * ## Application Task
 * Application task is split in few stages:
 *  - C3GSARA_CONFIGURE_FOR_NETWORK:
 * Sets configuration to device to be able to connect to the network.
 *
 *  - C3GSARA_WAIT_FOR_CONNECTION:
 * Waits for the network registration indicated via CREG URC event and then checks
 * the connection status.
 *
 *  - C3GSARA_CONFIGURE_FOR_EXAMPLE:
 * Sets the device configuration for sending SMS or TCP/UDP messages depending on the selected demo example.
 *
 *  - C3GSARA_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 c3gsara_clear_app_buf ( void )
 * - static err_t c3gsara_process ( void )
 * - static void c3gsara_error_check( err_t error_flag )
 * - static void c3gsara_log_app_buf ( void )
 * - static err_t c3gsara_rsp_check ( uint8_t *rsp )
 * - static err_t c3gsara_configure_for_connection( void )
 * - static err_t c3gsara_check_connection( void )
 * - static err_t c3gsara_configure_for_messages( void )
 * - static err_t c3gsara_send_message( 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 "c3gsara.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                             ""              // 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                     "3G SARA click board - demo example."

// Application buffer size
#define APP_BUFFER_SIZE                     256
#define PROCESS_BUFFER_SIZE                 256

/**
 * @brief Example states.
 * @details Predefined enum values for application example state.
 */
typedef enum
{
    C3GSARA_CONFIGURE_FOR_NETWORK = 1,
    C3GSARA_WAIT_FOR_CONNECTION,
    C3GSARA_CONFIGURE_FOR_EXAMPLE,
    C3GSARA_EXAMPLE

} c3gsara_example_state_t;

static c3gsara_t c3gsara;
static log_t logger;

/**
 * @brief Application example variables.
 * @details Variables used in application example.
 */
static uint8_t app_buf[ APP_BUFFER_SIZE ] = { 0 };
static int32_t app_buf_len = 0;
static err_t error_flag;
static c3gsara_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 c3gsara_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 c3gsara_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.
 * @param[in] error_flag  Error flag to check.
 */
static void c3gsara_error_check ( err_t error_flag );

/**
 * @brief Logs application buffer.
 * @details This function logs data from application buffer.
 */
static void c3gsara_log_app_buf ( void );

/**
 * @brief Response check.
 * @details This function checks for response and
 * returns the status of response.
 * @param[in] rsp  Expected 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 c3gsara_rsp_check ( uint8_t *rsp );

/**
 * @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 c3gsara_configure_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 c3gsara_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 c3gsara_configure_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 c3gsara_example ( void );

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    c3gsara_cfg_t c3gsara_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.
    c3gsara_cfg_setup( &c3gsara_cfg );
    C3GSARA_MAP_MIKROBUS( c3gsara_cfg, MIKROBUS_1 );
    if ( UART_ERROR == c3gsara_init( &c3gsara, &c3gsara_cfg ) )
    {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );
        for ( ; ; );
    }
    
    c3gsara_set_power_state ( &c3gsara, C3GSARA_POWER_STATE_ON );
    
    c3gsara_process( );
    c3gsara_clear_app_buf( );

    // Check communication
    c3gsara_send_cmd( &c3gsara, C3GSARA_CMD_AT );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    c3gsara_error_check( error_flag );
    
    // Restart device
    #define RESTART_DEVICE "1,1"
    c3gsara_send_cmd_with_par( &c3gsara, C3GSARA_CMD_CFUN, RESTART_DEVICE );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    c3gsara_error_check( error_flag );
    
    log_info( &logger, " Application Task " );
    example_state = C3GSARA_CONFIGURE_FOR_NETWORK;
}

void application_task ( void )
{
    switch ( example_state )
    {
        case C3GSARA_CONFIGURE_FOR_NETWORK:
        {
            if ( C3GSARA_OK == c3gsara_configure_for_network( ) )
            {
                example_state = C3GSARA_WAIT_FOR_CONNECTION;
            }
            break;
        }
        case C3GSARA_WAIT_FOR_CONNECTION:
        {
            if ( C3GSARA_OK == c3gsara_check_connection( ) )
            {
                example_state = C3GSARA_CONFIGURE_FOR_EXAMPLE;
            }
            break;
        }
        case C3GSARA_CONFIGURE_FOR_EXAMPLE:
        {
            if ( C3GSARA_OK == c3gsara_configure_for_example( ) )
            {
                example_state = C3GSARA_EXAMPLE;
            }
            break;
        }
        case C3GSARA_EXAMPLE:
        {
            c3gsara_example( );
            break;
        }
        default:
        {
            log_error( &logger, " Example state." );
            break;
        }
    }
}

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 c3gsara_clear_app_buf ( void )
{
    memset( app_buf, 0, app_buf_len );
    app_buf_len = 0;
}

static err_t c3gsara_process ( void )
{
    uint8_t rx_buf[ PROCESS_BUFFER_SIZE ] = { 0 };
    int32_t rx_size = 0;
    rx_size = c3gsara_generic_read( &c3gsara, rx_buf, PROCESS_BUFFER_SIZE );
    if ( rx_size > 0 ) 
    {
        int32_t buf_cnt = app_buf_len;
        if ( ( ( app_buf_len + rx_size ) > APP_BUFFER_SIZE ) && ( app_buf_len > 0 ) ) 
        {
            buf_cnt = APP_BUFFER_SIZE - ( ( app_buf_len + rx_size ) - APP_BUFFER_SIZE );
            memmove ( app_buf, &app_buf[ APP_BUFFER_SIZE - buf_cnt ], buf_cnt );
        }
        for ( int32_t rx_cnt = 0; rx_cnt < rx_size; rx_cnt++ ) 
        {
            if ( rx_buf[ rx_cnt ] ) 
            {
                app_buf[ buf_cnt++ ] = rx_buf[ rx_cnt ];
                if ( app_buf_len < APP_BUFFER_SIZE )
                {
                    app_buf_len++;
                }
            }
        }
        return C3GSARA_OK;
    }
    return C3GSARA_ERROR;
}

static err_t c3gsara_rsp_check ( uint8_t *rsp )
{
    uint32_t timeout_cnt = 0;
    uint32_t timeout = 120000;
    c3gsara_clear_app_buf( );
    c3gsara_process( );
    while ( ( 0 == strstr( app_buf, rsp ) ) &&
            ( 0 == strstr( app_buf, C3GSARA_RSP_ERROR ) ) )
    {
        c3gsara_process( );
        if ( timeout_cnt++ > timeout )
        {
            c3gsara_clear_app_buf( );
            return C3GSARA_ERROR_TIMEOUT;
        }
        Delay_ms ( 1 );
    }
    Delay_ms ( 100 );
    c3gsara_process( );
    if ( strstr( app_buf, rsp ) )
    {
        return C3GSARA_OK;
    }
    else if ( strstr( app_buf, C3GSARA_RSP_ERROR ) )
    {
        return C3GSARA_ERROR_CMD;
    }
    else
    {
        return C3GSARA_ERROR_UNKNOWN;
    }
}

static void c3gsara_error_check ( err_t error_flag )
{
    switch ( error_flag )
    {
        case C3GSARA_OK:
        {
            c3gsara_log_app_buf( );
            break;
        }
        case C3GSARA_ERROR:
        {
            log_error( &logger, " Overflow!" );
            break;
        }
        case C3GSARA_ERROR_TIMEOUT:
        {
            log_error( &logger, " Timeout!" );
            break;
        }
        case C3GSARA_ERROR_CMD:
        {
            log_error( &logger, " CMD!" );
            break;
        }
        case C3GSARA_ERROR_UNKNOWN:
        default:
        {
            log_error( &logger, " Unknown!" );
            break;
        }
    }
    Delay_ms ( 500 );
}

static void c3gsara_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 c3gsara_configure_for_network ( void )
{
    err_t func_error = C3GSARA_OK;
#if ( ( DEMO_EXAMPLE == EXAMPLE_TCP_UDP ) || ( DEMO_EXAMPLE == EXAMPLE_SMS ) )
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    // Deregister from network
    #define DEREGISTER_FROM_NETWORK "2"
    c3gsara_send_cmd_with_par( &c3gsara, C3GSARA_CMD_COPS, DEREGISTER_FROM_NETWORK );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_error_check( error_flag );
    
    // Set SIM APN
    c3gsara_set_sim_apn( &c3gsara, SIM_APN );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_error_check( error_flag );

    // Enable full functionality
    #define FULL_FUNCTIONALITY "1"
    c3gsara_send_cmd_with_par( &c3gsara, C3GSARA_CMD_CFUN, FULL_FUNCTIONALITY );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_error_check( error_flag );

    // Enable network registartion
    #define ENABLE_REG "2"
    c3gsara_send_cmd_with_par( &c3gsara, C3GSARA_CMD_CREG, ENABLE_REG );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_error_check( error_flag );
    
    // Automatic registration
    #define AUTOMATIC_REGISTRATION "0"
    c3gsara_send_cmd_with_par( &c3gsara, C3GSARA_CMD_COPS, AUTOMATIC_REGISTRATION );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_error_check( error_flag );
#endif
    return func_error;
}

static err_t c3gsara_check_connection ( void )
{
#if ( ( DEMO_EXAMPLE == EXAMPLE_TCP_UDP ) || ( DEMO_EXAMPLE == EXAMPLE_SMS ) )
    #define CONNECTED "+CREG: 2,1"
    c3gsara_send_cmd_check ( &c3gsara, C3GSARA_CMD_CREG );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    c3gsara_error_check( error_flag );
    if ( strstr( app_buf, CONNECTED ) )
    {
        Delay_ms ( 100 );
        c3gsara_process( );
        c3gsara_log_app_buf( );
        log_printf( &logger, "\r\n" );
        c3gsara_clear_app_buf( );
        // Check signal quality
        c3gsara_send_cmd( &c3gsara, C3GSARA_CMD_CSQ );
        error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
        c3gsara_error_check( error_flag );
        return error_flag;
    }
    Delay_ms ( 1000 );
    return C3GSARA_ERROR;
#endif
    return C3GSARA_OK;
}

static err_t c3gsara_configure_for_example ( void )
{
    err_t func_error = C3GSARA_OK;
#if ( DEMO_EXAMPLE == EXAMPLE_TCP_UDP )
    #define ACTIVATE_PDP_CONTEXT "1,1"
    c3gsara_send_cmd_with_par( &c3gsara, C3GSARA_CMD_CGACT, ACTIVATE_PDP_CONTEXT );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_error_check( error_flag );
    #define ACTIVATE_PDP_PROFILE "1,3"
    c3gsara_send_cmd_with_par( &c3gsara, C3GSARA_CMD_UPSDA, ACTIVATE_PDP_PROFILE );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_error_check( error_flag );
#elif ( DEMO_EXAMPLE == EXAMPLE_SMS )
    c3gsara_send_cmd_with_par( &c3gsara, C3GSARA_CMD_CMGF, SMS_MODE );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_error_check( error_flag );
#else
    #error "No demo example selected"
#endif
    return func_error;
}

static err_t c3gsara_example ( void )
{
    err_t func_error = C3GSARA_OK;
#if ( DEMO_EXAMPLE == EXAMPLE_TCP_UDP )
    uint8_t cmd_buf[ 100 ] = { 0 };
    uint8_t 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"
    c3gsara_send_cmd_with_par ( &c3gsara, C3GSARA_CMD_USOCR, TCP_PROTOCOL );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    socket_num_buf = strstr( app_buf, RSP_USOCR ) + strlen ( RSP_USOCR );
    tcp_socket_num[ 0 ] = *socket_num_buf;
    c3gsara_error_check( error_flag );

    // Create UDP socket
    #define UDP_PROTOCOL "17"
    c3gsara_send_cmd_with_par ( &c3gsara, C3GSARA_CMD_USOCR, UDP_PROTOCOL );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    socket_num_buf = strstr( app_buf, RSP_USOCR ) + strlen ( RSP_USOCR );
    udp_socket_num[ 0 ] = *socket_num_buf;
    c3gsara_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 );
    c3gsara_send_cmd_with_par( &c3gsara, C3GSARA_CMD_USOCO, cmd_buf );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_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 );
    c3gsara_send_cmd_with_par ( &c3gsara, C3GSARA_CMD_USOCO, cmd_buf );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_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, "\"" );
    c3gsara_send_cmd_with_par ( &c3gsara, C3GSARA_CMD_USOWR, cmd_buf );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_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 ( ; ; )
    {
        c3gsara_process( );
        uint8_t * __generic_ptr start_response_buf = strstr( app_buf, urc_buf );
        if ( start_response_buf )
        {
            Delay_ms ( 100 );
            c3gsara_process( );
            uint8_t response_len_buf[ 5 ] = { 0 };
            uint8_t * __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 );
            c3gsara_log_app_buf( );
            c3gsara_clear_app_buf( );
            c3gsara_send_cmd_with_par ( &c3gsara, C3GSARA_CMD_USORD, cmd_buf );
            error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
            func_error |= error_flag;
            c3gsara_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, "\"" );
    c3gsara_send_cmd_with_par( &c3gsara, C3GSARA_CMD_USOWR, cmd_buf );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_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 ( ; ; )
    {
        c3gsara_process( );
        uint8_t * __generic_ptr start_response_buf = strstr( app_buf, urc_buf );
        if ( start_response_buf )
        {
            Delay_ms ( 100 );
            c3gsara_process( );
            uint8_t response_len_buf[ 5 ] = { 0 };
            uint8_t * __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 );
            c3gsara_log_app_buf( );
            c3gsara_clear_app_buf( );
            c3gsara_send_cmd_with_par ( &c3gsara, C3GSARA_CMD_USORF, cmd_buf );
            error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
            func_error |= error_flag;
            c3gsara_error_check( error_flag );
            break;
        }
        if ( timeout_cnt++ > timeout )
        {
            break;
        }
        Delay_ms ( 1 );
    }
    
    // Close TCP socket
    c3gsara_send_cmd_with_par ( &c3gsara, C3GSARA_CMD_USOCL, tcp_socket_num );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_error_check( error_flag );
    
    // Close UDP socket
    c3gsara_send_cmd_with_par ( &c3gsara, C3GSARA_CMD_USOCL, udp_socket_num );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_error_check( error_flag );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
#elif ( DEMO_EXAMPLE == EXAMPLE_SMS )
    // Check SMS mode
    #define CMGF_PDU "+CMGF: 0"
    #define CMGF_TXT "+CMGF: 1"
    c3gsara_send_cmd_check( &c3gsara, C3GSARA_CMD_CMGF );
    error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
    func_error |= error_flag;
    c3gsara_error_check( error_flag );
    if ( strstr( app_buf, CMGF_PDU ) )
    {
        // Send SMS in PDU mode
        c3gsara_send_sms_pdu( &c3gsara, SIM_SMSC, PHONE_NUMBER_TO_MESSAGE, MESSAGE_CONTENT );
        error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
        func_error |= error_flag;
        c3gsara_error_check( error_flag );
    }
    else if ( strstr( app_buf, CMGF_TXT ) )
    {
        // Send SMS in TXT mode
        c3gsara_send_sms_text ( &c3gsara, PHONE_NUMBER_TO_MESSAGE, MESSAGE_CONTENT );
        error_flag = c3gsara_rsp_check( C3GSARA_RSP_OK );
        func_error |= error_flag;
        c3gsara_error_check( error_flag );
    }
    // 30 seconds delay
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
#else
    #error "No demo example selected"
#endif
    return func_error;
}

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

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