Beginner
10 min

Add RFID reader/writer capabilities to your project with CR95HF and STM32F031K6

RFID (Radio Frequency Identification) multi-protocol contactless transceiver

RFid Click with Nucleo 32 with STM32F031K6 MCU

Published Oct 01, 2024

Click board™

RFid Click

Dev. board

Nucleo 32 with STM32F031K6 MCU

Compiler

NECTO Studio

MCU

STM32F031K6

Achieve communication with RFID tags and supports various applications such as tracking, security systems, and identification

A

A

Hardware Overview

How does it work?

RFid Click is based on the CR95HF, a multi-protocol contactless transceiver from STMicroelectronics. This board supports ISO/IEC 14443 type A and B, ISO/IEC 15693, and ISO/IEC 18092 communication protocols (tags). In addition, it also supports the detection, reading, and writing of NFC forum type 1, 2, 3, and 4 tags with incorporated internal antenna. The CR95HF integrates an Analog Front End to provide the 13.56MHz Air Interface. It manages frame coding and decoding in Reader mode for standard applications such as near-field communication (NFC), proximity, and vicinity standards. The CR95HF has two operating modes: Wait for Event

(WFE) and Active Mode of operation. In Active mode, the CR95HF communicates actively with a tag or an external host. The WFE mode includes four low-consumption states: Power-up, Hibernate, Sleep, and Tag Detector, allowing the transceiver to switch from one mode to another. All states except Power-Up are software-accessible. While the CR95HF is in any of these, communication with the MCU is impossible. For normal communication, the transceiver must be woken up first. RFid Click can communicate with the host MCU using UART or SPI serial interfaces over the mikroBUS™ socket. This Click board™ comes with A and B jumpers with which the function of two multiplex pins is

selected. Depending on their position, the pins can be used as UART or interrupt (input and output) pins (interrupt by default). These jumpers must be set to the B position for use with the UART interface, thus losing the interrupt function pins. The SSSI0 and SSI1 pins serve for communication interface selection based on their logic states. This Click board™ can only be operated with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used as a reference for further development.

RFid Click hardware overview image

Features overview

Development board

Nucleo 32 with STM32F031K6 MCU board provides an affordable and flexible platform for experimenting with STM32 microcontrollers in 32-pin packages. Featuring Arduino™ Nano connectivity, it allows easy expansion with specialized shields, while being mbed-enabled for seamless integration with online resources. The

board includes an on-board ST-LINK/V2-1 debugger/programmer, supporting USB reenumeration with three interfaces: Virtual Com port, mass storage, and debug port. It offers a flexible power supply through either USB VBUS or an external source. Additionally, it includes three LEDs (LD1 for USB communication, LD2 for power,

and LD3 as a user LED) and a reset push button. The STM32 Nucleo-32 board is supported by various Integrated Development Environments (IDEs) such as IAR™, Keil®, and GCC-based IDEs like AC6 SW4STM32, making it a versatile tool for developers.

Nucleo 32 with STM32F031K6 MCU double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

ARM Cortex-M0

MCU Memory (KB)

32

Silicon Vendor

STMicroelectronics

Pin count

32

RAM (Bytes)

4096

You complete me!

Accessories

Click Shield for Nucleo-32 is the perfect way to expand your development board's functionalities with STM32 Nucleo-32 pinout. The Click Shield for Nucleo-32 provides two mikroBUS™ sockets to add any functionality from our ever-growing range of Click boards™. We are fully stocked with everything, from sensors and WiFi transceivers to motor control and audio amplifiers. The Click Shield for Nucleo-32 is compatible with the STM32 Nucleo-32 board, providing an affordable and flexible way for users to try out new ideas and quickly create prototypes with any STM32 microcontrollers, choosing from the various combinations of performance, power consumption, and features. The STM32 Nucleo-32 boards do not require any separate probe as they integrate the ST-LINK/V2-1 debugger/programmer and come with the STM32 comprehensive software HAL library and various packaged software examples. This development platform provides users with an effortless and common way to combine the STM32 Nucleo-32 footprint compatible board with their favorite Click boards™ in their upcoming projects.

Click Shield for Nucleo-32 accessories 1 image

RFID tag operating at 13.56MHz adheres to the ISO14443-A standard, ensuring high-frequency communication. This proximity card technology, often exemplified by MIFARE cards, facilitates secure and contactless interactions in applications like access control, public transport, and payment systems. The ISO14443-A standard defines the communication protocol, incorporating anti-collision mechanisms for simultaneous card handling. These RFID tags possess variable memory capacities, ranging from a few bytes to kilobytes, catering to diverse application needs. Ensuring data security, the standard integrates features such as encryption and authentication. These tags, exemplified by MIFARE technology, are widely used for their efficiency and are vital in enhancing convenience and security in diverse identification and access scenarios.

RFid Click accessories image

Used MCU Pins

mikroBUS™ mapper

Interface Selection
PA0
AN
Interface Selection
PA11
RST
SPI Chip Select
PA4
CS
SPI Clock
PB3
SCK
SPI Data OUT
PB4
MISO
SPI Data IN
PB5
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
Interrupt Output
PA8
PWM
Interrupt Output
PA12
INT
UART TX
PA10
TX
UART RX
PA9
RX
NC
NC
SCL
NC
NC
SDA
NC
NC
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

RFid Click Schematic schematic

Step by step

Project assembly

Click Shield for Nucleo-144 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Nucleo 32 with STM32F031K6 MCU as your development board.

Click Shield for Nucleo-144 front image hardware assembly
Nucleo 144 with STM32L4A6ZG MCU front image hardware assembly
Stepper 22 Click front image hardware assembly
Prog-cut hardware assembly
Stepper 22 Click complete accessories setup image hardware assembly
Nucleo-32 with STM32 MCU 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
STM32 M4 Clicker HA MCU/Select 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 RFID Click driver.

Key functions:

  • rfid_select_communication_interface - Select communication interface

  • rfid_get_tag_uid - Get RFID tag uid function

  • rfid_get_device_id - RFID get device id 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 main.c
 * @brief RFID Click example
 *
 * # Description
 * This example demonstrates the use of RFID Click board 
 * by reading MIFARE ISO/IEC 14443 type A tag UID.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver, selects the communication interface and performs
 * the click default configuration.
 *
 * ## Application Task
 * If there's a tag detected, it reads its UID and displays it on USB UART.
 *
 * @note
 * It is recommended to tie SSI_0, SSI_1 to VCC/GND at power-up, depending on 
 * the communication interface selection by A and B on-board jumpers. 
 * SSI_0 - UART: 0 SPI: 1
 * SSI_1 - UART: 0 SPI: 0
 * 
 * Only tags with 4-byte or 7-byte UIDs are compatible with this example.
 * We recommend MIKROE-1475 - an RFiD tag 13.56MHz compliant with ISO14443-A standard.
 * 
 * 
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "rfid.h"

static rfid_t rfid;
static log_t logger;

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    rfid_cfg_t rfid_cfg;  /**< Click config object. */

    /** 
     * Logger initialization.
     * Default baud rate: 115200
     * Default log level: LOG_LEVEL_DEBUG
     * @note If USB_UART_RX and USB_UART_TX 
     * are defined as HAL_PIN_NC, you will 
     * need to define them manually for log to work. 
     * See @b LOG_MAP_USB_UART macro definition for detailed explanation.
     */
    LOG_MAP_USB_UART( log_cfg );
    log_init( &logger, &log_cfg );
    log_info( &logger, " Application Init " );
    Delay_ms( 100 );

    // Click initialization.

    rfid_cfg_setup( &rfid_cfg );
    RFID_MAP_MIKROBUS( rfid_cfg, MIKROBUS_1 );
    err_t error_flag = rfid_init( &rfid, &rfid_cfg );
    if ( error_flag != RFID_OK ) 
    {
        log_error( &logger, " Please, run program again... " );
        for ( ; ; );
    }
    
    log_printf( &logger, " Selecting communication interface... \r\n" );
    error_flag = rfid_select_communication_interface ( &rfid, RFID_SPI );
    if ( error_flag != RFID_OK ) 
    {
        log_error( &logger, " Please, run program again... " );
        for ( ; ; );
    }
    
    log_printf( &logger, " Configuring the device... \r\n" );
    error_flag = rfid_default_cfg ( &rfid );
    if ( error_flag != RFID_OK ) 
    {
        log_error( &logger, " Please, run program again... " );
        for ( ; ; );
    }
    
    log_printf( &logger, " The device has been configured! \r\n" );
}

void application_task ( void ) 
{
    uint8_t tag_uid[ 20 ] = { 0 };
    uint8_t tag_len = rfid_get_tag_uid( &rfid, RFID_ISO_14443A, tag_uid );
    if ( tag_len > 0 )
    {
        log_printf( &logger, " TAG UID: " );
        for ( uint8_t cnt = 0; cnt < tag_len; cnt++ )
        {
            log_printf( &logger, "0x%.2X ", ( uint16_t ) tag_uid[ cnt ] );
        }
        log_printf( &logger, "\r\n----------------------------------\r\n" );
        Delay_ms( 1000 );
    }
}

void main ( void ) 
{
    application_init( );

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

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

Additional Support

Resources

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