Intermediate
30 min

Create contactless access control systems with PIC32MX470F512H

NFC Extend: Your tags, your way, with endless antenna possibilities

NFC Extend Click with 6LoWPAN clicker

Published Oct 18, 2023

Click board™

NFC Extend Click

Dev. board

6LoWPAN clicker

Compiler

NECTO Studio

MCU

PIC32MX470F512H

With NFC Extend, you have the power to shape your NFC experience with custom antennas, allowing you to personalize and adapt your tags to fit unique requirements

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Hardware Overview

How does it work?

NFC Extend Click is based on the ST25DV16K, a compact NFC tag IC from STMicroelectronics. The Click board™ itself has a reasonably small number of components because most of the interface and EEPROM memory circuitry is already integrated on the ST25DV16K IC. The I2C / SMBus compatible serial interface lines, along with the GPO pin, which also works in the open drain configuration, are pulled up by the on-board resistors. The 2-Wire lines are routed to the respective I2C lines of the mikroBUS™ (SCK and SDA), while the GPO pin of the main IC is routed to the INT pin of the mikroBUS™. Depending on the application requirements various shapes and sizes of 13.56 MHz external antenna can be used by connecting them to CN1 (male U.FL) connector. This Click can utilize new antennas that we have recently

released. The ST25DV16K uses the I2C/SMBus compatible communication interface, offering a fast transfer mode (FTM), to achieve a fast link between RF and contact worlds, via a 256 byte buffer called Mailbox. This mailbox dynamic buffer of 256 byte can be filled or emptied via either RF or I2C. There is also the INT pin available, which indicates incoming event to the contact side, like RF Field changes, RF activity in progress, RF writing completion or Mailbox message availability. The built in energy harvesting element can deliver µW of power when external conditions make it possible. The integrated RF management allows the NFC Extend Click to ignore RF requests. All these features can be programmed by setting static and/or dynamic registers of the ST25DV16K. The ST25DV16K can be partially customized

using configuration registers located in the E2 system area. More information about all the registers can be found in the ST25DV16K datasheet. However, provided library contains functions that simplify the use of the NFC Extend Click. The included application example demonstrates their functionality and it can be used as a reference for custom design. 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.

NFC Extend Click top side image
NFC Extend Click bottom side image

Features overview

Development board

6LoWPAN Clicker is a compact starter development board that brings the flexibility of add-on Click boards™ to your favorite microcontroller, making it a perfect starter kit for implementing your ideas. It comes with an onboard 32-bit PIC microcontroller, the PIC32MX470F512H from Microchip, a USB connector, LED indicators, buttons, a mikroProg connector, and a header for interfacing with external electronics. Along with this microcontroller, the board also contains a 2.4GHz ISM band transceiver, allowing you to add wireless communication to your target application. Its compact design provides a fluid and immersive working experience, allowing access anywhere

and under any circumstances. Each part of the 6LoWPAN Clicker development kit contains the components necessary for the most efficient operation of the same board. In addition to the possibility of choosing the 6LoWPAN Clicker programming method, using USB HID mikroBootloader, or through an external mikroProg connector for PIC, dsPIC, or PIC32 programmer, the Clicker board also includes a clean and regulated power supply module for the development kit. The USB Micro-B connection can provide up to 500mA of current for the Clicker board, which is more than enough to operate all onboard and additional modules, or it can power

over two standard AA batteries. All communication methods that mikroBUS™ itself supports are on this board, including the well-established mikroBUS™ socket, reset button, and several buttons and LED indicators. 6LoWPAN Clicker is an integral part of the Mikroe ecosystem, allowing you to create a new application in minutes. Natively supported by Mikroe software tools, it covers many aspects of prototyping thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.

6LoWPAN clicker double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC32

MCU Memory (KB)

512

Silicon Vendor

Microchip

Pin count

64

RAM (Bytes)

131072

You complete me!

Accessories

Circular NFC R35 Antenna is a circular-shaped PCB antenna designed to be used as an extension of development boards and placed remotely on desired places such as plastic casing, existing products, or even under displays. The antenna is designed in a circular shape with a diameter of 35mm (35x42mm WxL) and seven coil turns. It's also important to mention that this antenna can be used for NFC and RFID applications that work on 13.56MHz frequency.

NFC Extend Click accessories 1 image

UMCC - Ultraminiature Coax Connector is an ultra-low profile 1.37mm diameter coax female-to-female interconnect solution that meets the ever-growing demand for miniaturization in next-generation wireless applications. Crafted as double-ended jumpers and inter-series assemblies, the UMCC cable also offers PCB jack receptacles for seamless board mount applications. With a length (L) of 200mm, a 2.5mm mated height (H), and a 50 Ohm characteristic impedance, the UMCC Connector Type III ensures optimal performance across a broad frequency range from DC to 6 GHz.

NFC Extend Click accessories 2 image

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
NC
NC
RST
NC
NC
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
Interrupt
RD0
INT
NC
NC
TX
NC
NC
RX
I2C Clock
RD10
SCL
I2C Data
RD9
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

NFC Extend Click Schematic schematic

Step by step

Project assembly

PIC32MZ clicker front image hardware assembly

Start by selecting your development board and Click board™. Begin with the 6LoWPAN clicker as your development board.

PIC32MZ clicker front image hardware assembly
GNSS2 Click front image hardware assembly
Prog-cut hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
Board mapper by product7 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
Flip&Click PIC32MZ 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 NFC Extend Click driver.

Key functions:

  • nfcextend_i2c_set - This function writes data to the chip.

  • nfcextend_i2c_get - This function reads data from the chip.

  • nfcextend_digital_read_int - This function reads the digital signal from the INT pin.

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 NfcExtend Click example
 * 
 * # Description
 * This example showcases how to configure and use the NFC Extend Click. The Click is an NFC tag 
 * interface which uses the I2C serial interface and an RF link interface in order to communicate.
 * The example requires the ST25 NFC Tap application which can be downloaded to your phone.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * This function initializes and configures the logger and Click modules.
 * 
 * ## Application Task  
 * This function waits for the interrupt signal, after which it expects data transfers. Once
 * some data has been detected it will open a communication channel with the device transmitting
 * it and show the received data in the UART console.
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "nfcextend.h"

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

static nfcextend_t nfcextend;
static log_t logger;

uint8_t default_password[ NFCEXTEND_PASSWORD_LEN ] = { 0 };

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

void wait_for_interrupt ( )
{
    uint8_t int_pin_flag;
    uint16_t timer_counter;

    int_pin_flag = nfcextend_digital_read_int( &nfcextend );
    timer_counter = 0;
    
    while ( ( int_pin_flag == 1 ) && ( timer_counter <= 300 ) )
    {
        Delay_ms ( 1 );
        timer_counter++;
        int_pin_flag = nfcextend_digital_read_int( &nfcextend );
    }

    if ( timer_counter <= 300 )
    {
        int_pin_flag = nfcextend_digital_read_int( &nfcextend );

        while ( int_pin_flag == 0 )
        {
            int_pin_flag = nfcextend_digital_read_int( &nfcextend );
        }
    }

    timer_counter = 0;
}

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

void application_init ( )
{
    log_cfg_t log_cfg;
    nfcextend_cfg_t cfg;

    uint8_t init_status_flag;

    /** 
     * 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.

    nfcextend_cfg_setup( &cfg );
    NFCEXTEND_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    nfcextend_init( &nfcextend, &cfg );

    nfcextend_password_present( &nfcextend, default_password );
    Delay_ms ( 100 );

    init_status_flag = nfcextend_default_cfg( &nfcextend );
    Delay_ms ( 100 );

    if ( 1 == init_status_flag )
    {
        log_printf( &logger, " * App init failed. *\r\n" );
    }
    else if ( 0 == init_status_flag ) 
    {
        log_printf( &logger, " * App init done. *\r\n" );
    }
    log_printf( &logger, "-----------------------\r\n" );
}

void application_task ( )
{
    nfcextend_block_t block;

    uint8_t temp_buf[ 258 ];
    uint16_t message_len;
    uint16_t cnt;

    block.memory_area = NFCEXTEND_MEMORY_DYNAMIC;
    block.reg_addr = NFCEXTEND_DYNAMIC_REG_MB_CTRL;
    block.data_buf = temp_buf;
    block.len = 1;

    wait_for_interrupt( );
    nfcextend_i2c_get( &nfcextend, &block );

    if ( ( temp_buf[ 0 ] & 0x04 ) == 0x04 )
    {
        block.reg_addr = NFCEXTEND_DYNAMIC_REG_MB_LEN;
        block.data_buf = &temp_buf[ 0 ];

        wait_for_interrupt( );
        nfcextend_i2c_get( &nfcextend, &block );

        message_len = temp_buf[ 0 ] + 1;

        block.memory_area = NFCEXTEND_MEMORY_MAILBOX;
        block.reg_addr = NFCEXTEND_MAILBOX_REG_BYTE_0;
        block.data_buf = &temp_buf[ 0 ];
        block.len = message_len;

        wait_for_interrupt( );
        nfcextend_i2c_get( &nfcextend, &block );

        log_printf( &logger, " ** Message length:  %u Bytes**\r\n", message_len);
        
        log_printf( &logger, " ------------------------------\r\n" );
        log_printf( &logger, " ** Message START **\r\n" );

        for ( cnt = 0; cnt < message_len; cnt++ )
        {
            log_printf( &logger, " %u : 0x%x\r\n", cnt, ( uint16_t ) temp_buf[ cnt ] );
        }

        log_printf( &logger, " ** Message END **\r\n" );
        log_printf( &logger, " ------------------------------\r\n" );
    }
}

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;
}

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

Additional Support

Resources

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