Beginner
10 min

Provide wireless connectivity to your projects with ESP-WROOM-02 and ATmega328P

Empowering your IoT ecosystem with supercharged WiFi!

WiFi ESP Click with Arduino UNO Rev3

Published Feb 14, 2024

Click board™

WiFi ESP Click

Dev. board

Arduino UNO Rev3

Compiler

NECTO Studio

MCU

ATmega328P

Transform your environment into a smart oasis with our WiFi module, designed to effortlessly integrate into your projects, providing the connectivity backbone for your connected lifestyle.

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Hardware Overview

How does it work?

WiFi ESP Click is based on the ESP-WROOM-02, a fully integrated WiFi module from Espressif. It carries the well-known work-horse ESP8266EX, a highly integrated SoC solution that meets continuous demands for efficient power usage, compact design, and reliable performance in the industry. Besides the WiFi functionalities, ESP8266EX integrates an enhanced version of Tensilica’s L106 Diamond series 32-bit processor and on-chip SRAM, as well as antenna switches, RF balun, power amplifier, low noise receiver amplifier, filters, and power management modules. The module also includes 2MB of SPI flash to store a user program. With the complete and self-contained WiFi networking capabilities, it

can perform as either a standalone application (WROOM module itself) or the slave to an MCU host, which is the primary intention of the click board as a whole. So, this click board is applied to any microcontroller design as a WiFi adaptor through the UART interface (RX, TX lines on mikroBUS pin socket). The WiFi ESP Click comes with exposed 5 GPIOs of the module, which are part of the HSPI/GPIO interface of the module. The GPIO0 is used to enter the ESP8266EX’s UART download mode by shortening it with the GND just next to it. This way, you can upgrade the module’s firmware or upload a custom one. WiFi ESP Click communicates with the host MCU using the UART interface as its default communication

protocol at the 115200 baud rate. Besides standard UART RX and TX lines, the host MCU is also connected to the WiFi ESP Click with EN and RST lines. The first one turns off the module with a LOW logic state, while the latter is used to reset the ESP8266EX. You can also use the UART interface to communicate with the ESP-WROOM-O2 module by the AT commands set. This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. Also, it comes equipped with a library containing functions and an example code that can be used as a reference for further development.

WiFi ESP Click hardware overview image

Features overview

Development board

Arduino UNO is a versatile microcontroller board built around the ATmega328P chip. It offers extensive connectivity options for various projects, featuring 14 digital input/output pins, six of which are PWM-capable, along with six analog inputs. Its core components include a 16MHz ceramic resonator, a USB connection, a power jack, an

ICSP header, and a reset button, providing everything necessary to power and program the board. The Uno is ready to go, whether connected to a computer via USB or powered by an AC-to-DC adapter or battery. As the first USB Arduino board, it serves as the benchmark for the Arduino platform, with "Uno" symbolizing its status as the

first in a series. This name choice, meaning "one" in Italian, commemorates the launch of Arduino Software (IDE) 1.0. Initially introduced alongside version 1.0 of the Arduino Software (IDE), the Uno has since become the foundational model for subsequent Arduino releases, embodying the platform's evolution.

Arduino UNO Rev3 double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

AVR

MCU Memory (KB)

32

Silicon Vendor

Microchip

Pin count

28

RAM (Bytes)

2048

You complete me!

Accessories

Click Shield for Arduino UNO has two proprietary mikroBUS™ sockets, allowing all the Click board™ devices to be interfaced with the Arduino UNO board without effort. The Arduino Uno, a microcontroller board based on the ATmega328P, provides an affordable and flexible way for users to try out new concepts and build prototypes with the ATmega328P microcontroller from various combinations of performance, power consumption, and features. The Arduino Uno has 14 digital input/output pins (of which six can be used as PWM outputs), six analog inputs, a 16 MHz ceramic resonator (CSTCE16M0V53-R0), a USB connection, a power jack, an ICSP header, and reset button. Most of the ATmega328P 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 Arduino UNO board with our Click Shield for Arduino UNO, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.

Click Shield for Arduino UNO accessories 1 image

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Reset
PD2
RST
Chip Enable
PB2
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
PD0
TX
UARTRX
PD1
RX
NC
NC
SCL
NC
NC
SDA
NC
NC
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

WiFi ESP Click Schematic schematic

Step by step

Project assembly

Click Shield for Arduino UNO front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Arduino UNO Rev3 as your development board.

Click Shield for Arduino UNO front image hardware assembly
Arduino UNO Rev3 front image hardware assembly
Barometer 13 Click front image hardware assembly
Prog-cut hardware assembly
Arduino UNO Rev3 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
Arduino UNO 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 WiFi ESP Click driver.

Key functions:

  • wifiesp_send_cmd - Sends AT command to the module.

  • wifiesp_generic_write - Generic write function.

  • wifiesp_generic_read - Generic read 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 wifiesp Click example
 * 
 * # Description
 * This example connects to the desired WiFi network and then
 * creates web server on the IP address assigned to the click board.
 * The user can connect to the server via web browser.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes driver and wifi communication, then connects to the desired WiFi network
 * and creates web server on the IP address assigned to the click board.
 * 
 * ## Application Task  
 * Waits for the client request (paste IP address in your web browser and 
 * refresh to send a request).
 * The click board will respond by sending a page content to the client.
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "wifiesp.h"
#include "string.h"
#include "conversions.h"

#define APP_SSID                            "MikroE Public"
#define APP_PASSWORD                        "mikroe.guest"

#define PROCESS_BUFFER_SIZE                 610

// ------------------------------------------------------------------ VARIABLES

uint8_t page[ ] = "<a href=\"https://www.mikroe.com/\">MikroElektronika</a>\
<h1 style=\"color:red;\">WiFi ESP click board</h1>";
uint8_t page_len[ 10 ] = { 0 };
uint8_t send_buf[ 10 ] = { 0 };
static uint8_t link_id[ 2 ] = { 0 };

static wifiesp_t wifiesp;
static log_t logger;

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

static err_t app_error_flag;

// ------------------------------------------------------- ADDITIONAL FUNCTIONS

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

static void wifiesp_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 wifiesp_process ( void )
{
    uint8_t rx_buf[ PROCESS_BUFFER_SIZE ] = { 0 };
    int32_t rx_size = 0;
    rx_size = wifiesp_generic_read( &wifiesp, rx_buf, PROCESS_BUFFER_SIZE );
    if ( rx_size > 0 ) 
    {
        int32_t buf_cnt = app_buf_len;
        if ( ( ( app_buf_len + rx_size ) > PROCESS_BUFFER_SIZE ) && ( app_buf_len > 0 ) ) 
        {
            buf_cnt = PROCESS_BUFFER_SIZE - ( ( app_buf_len + rx_size ) - PROCESS_BUFFER_SIZE );
            memmove ( app_buf, &app_buf[ PROCESS_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 < PROCESS_BUFFER_SIZE )
                {
                    app_buf_len++;
                }
            }
        }
        return WIFIESP_OK;
    }
    return WIFIESP_ERROR;
}

static err_t wifiesp_rsp_check ( char * response )
{
    uint32_t timeout_cnt = 0;
    uint32_t timeout = 120000;
    wifiesp_clear_app_buf( );
    wifiesp_process( );
    while ( ( 0 == strstr( app_buf, response ) ) &&
            ( 0 == strstr( app_buf, WIFIESP_RSP_ERROR ) ) )
    {
        wifiesp_process( );
        if ( timeout_cnt++ > timeout )
        {
            wifiesp_clear_app_buf( );
            return WIFIESP_ERROR_TIMEOUT;
        }
        Delay_ms( 1 );
    }
    Delay_ms( 5 );
    wifiesp_process( );
    if ( strstr( app_buf, response ) )
    {
        return WIFIESP_OK;
    }
    else if ( strstr( app_buf, WIFIESP_RSP_ERROR ) )
    {
        return WIFIESP_ERROR_CMD;
    }
    return WIFIESP_ERROR_UNKNOWN;
}

static void wifiesp_error_check( err_t error_flag )
{
    switch ( error_flag )
    {
        case WIFIESP_OK:
        {
            wifiesp_log_app_buf( );
            break;
        }
        case WIFIESP_ERROR:
        {
            log_error( &logger, " Overflow!" );
            break;
        }
        case WIFIESP_ERROR_TIMEOUT:
        {
            log_error( &logger, " Timeout!" );
            break;
        }
        case WIFIESP_ERROR_CMD:
        {
            log_error( &logger, " CMD!" );
            break;
        }
        case WIFIESP_ERROR_UNKNOWN:
        default:
        {
            log_error( &logger, " Unknown!" );
            break;
        }
    }
    log_printf( &logger, "\r\n-----------------------------------\r\n" );
    Delay_ms( 500 );
}

void wifi_communication_init( void )
{
    wifiesp_process( ); // dummy read
    wifiesp_clear_app_buf( );
    
    wifiesp_send_cmd( &wifiesp, WIFIESP_CHECK, NULL );
    app_error_flag = wifiesp_rsp_check( WIFIESP_RSP_OK );
    wifiesp_error_check( app_error_flag );
    
    wifiesp_send_cmd( &wifiesp, WIFIESP_RESTORE, NULL );
    app_error_flag = wifiesp_rsp_check( WIFIESP_RSP_OK );
    wifiesp_error_check( app_error_flag );
    uart_clear ( &wifiesp.uart );
    
    wifiesp_send_cmd( &wifiesp, WIFIESP_CHECK_FIRMWARE, NULL );
    app_error_flag = wifiesp_rsp_check( WIFIESP_RSP_OK );
    wifiesp_error_check( app_error_flag );
    
    wifiesp_send_cmd( &wifiesp, WIFIESP_SET_MODE, "1" );
    app_error_flag = wifiesp_rsp_check( WIFIESP_RSP_OK );
    wifiesp_error_check( app_error_flag );
    
    wifiesp_clear_app_buf( );
    strcpy ( app_buf, "\"" );
    strcat ( app_buf, APP_SSID );
    strcat ( app_buf, "\",\"" );
    strcat ( app_buf, APP_PASSWORD );
    strcat ( app_buf, "\"" );
    app_buf_len = strlen ( app_buf );
    wifiesp_send_cmd( &wifiesp, WIFIESP_CONNECT, app_buf );
    wifiesp_clear_app_buf ( );
    app_error_flag = wifiesp_rsp_check( WIFIESP_RSP_OK );
    wifiesp_error_check( app_error_flag );
    
    wifiesp_send_cmd( &wifiesp, WIFIESP_SET_MULTIPLE_CONNECTION, "1" );
    app_error_flag = wifiesp_rsp_check( WIFIESP_RSP_OK );
    wifiesp_error_check( app_error_flag );
    
    wifiesp_send_cmd( &wifiesp, WIFIESP_SET_AS_SERVER, "1,80" );
    app_error_flag = wifiesp_rsp_check( WIFIESP_RSP_OK );
    wifiesp_error_check( app_error_flag );
    
    wifiesp_send_cmd( &wifiesp, WIFIESP_GET_IP, NULL );
    app_error_flag = wifiesp_rsp_check( WIFIESP_RSP_OK );
    wifiesp_error_check( app_error_flag );
}

static void wifiesp_str_cut_chr ( uint8_t *str, uint8_t chr )
{
    uint16_t cnt_0 = 0;
    uint16_t cnt_1 = 0;
    for ( cnt_0 = 0; cnt_0 < strlen( str ); cnt_0++ )
    {
        if ( str[ cnt_0 ] == chr )
        {
            for ( cnt_1 = cnt_0; cnt_1 < strlen( str ); cnt_1++ )
            {
                str[ cnt_1 ] = str[ cnt_1 + 1 ];
            }
        }
    }
}

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

void application_init ( void )
{
    log_cfg_t log_cfg;
    wifiesp_cfg_t cfg;
    
    /** 
     * 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.
    wifiesp_cfg_setup( &cfg );
    WIFIESP_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    wifiesp_init( &wifiesp, &cfg );
    wifiesp_default_cfg( &wifiesp );
    Delay_ms( 1000 );
    
    // Communication initialization
    wifi_communication_init( );
    
    uint16_to_str ( strlen( page ), page_len );
    wifiesp_str_cut_chr ( page_len, ' ' );
    
    log_info( &logger, "Please connect to the IP address listed above.\r\n" );
}

void application_task ( void )
{
    if ( WIFIESP_OK == wifiesp_rsp_check( WIFIESP_RECEIVE ) ) 
    {
        link_id[ 0 ] = *( strstr( app_buf, WIFIESP_RECEIVE ) + 5 );
        strcpy ( send_buf, link_id );
        strcat ( send_buf, "," );
        strcat ( send_buf, page_len );
        wifiesp_str_cut_chr ( send_buf, ' ' );
        wifiesp_log_app_buf( );
        wifiesp_clear_app_buf( );
        Delay_ms( 100 );
        wifiesp_process( );
        wifiesp_log_app_buf( );
        wifiesp_send_cmd( &wifiesp, WIFIESP_SEND, send_buf );
        app_error_flag = wifiesp_rsp_check( WIFIESP_RSP_READY_FOR_SEND );
        wifiesp_log_app_buf( );
        Delay_ms( 100 );
        wifiesp_generic_write( &wifiesp, page, strlen( page ) );
        app_error_flag = wifiesp_rsp_check( WIFIESP_RSP_SEND_OK );
        wifiesp_error_check( app_error_flag );
        wifiesp_send_cmd( &wifiesp, WIFIESP_CLOSE, link_id );
        app_error_flag = wifiesp_rsp_check( WIFIESP_RSP_OK );
        wifiesp_error_check( app_error_flag );
        wifiesp_clear_app_buf( );
        
        wifiesp_process( );
        wifiesp_log_app_buf( );
        wifiesp_clear_app_buf( );
        uart_clear ( &wifiesp.uart );
        Delay_ms( 100 );
    }
}

void main ( void )
{
    application_init( );
    
    for ( ; ; )
    {
        application_task ( );
    }
}


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

Additional Support

Resources

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