Add RFID reader/writer capabilities to your project with CR95HF and STM32F071VB
RFID (Radio Frequency Identification) multi-protocol contactless transceiver
Published Jun 19, 2023
Click board™
RFid Click
Dev Board
UNI Clicker
Compiler
NECTO Studio
MCU
STM32F071VB
Achieve communication with RFID tags and supports various applications such as tracking, security systems, and identification
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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.
Features overview
Development board
UNI Clicker is a compact development board designed as a complete solution that brings the flexibility of add-on Click boards™ to your favorite microcontroller, making it a perfect starter kit for implementing your ideas. It supports a wide range of microcontrollers, such as different ARM, PIC32, dsPIC, PIC, and AVR from various vendors like Microchip, ST, NXP, and TI (regardless of their number of pins), four mikroBUS™ sockets for Click board™ connectivity, a USB connector, LED indicators, buttons, a debugger/programmer connector, and two 26-pin headers for interfacing with external electronics. Thanks to innovative manufacturing technology, it allows you to build
gadgets with unique functionalities and features quickly. Each part of the UNI Clicker development kit contains the components necessary for the most efficient operation of the same board. In addition to the possibility of choosing the UNI Clicker programming method, using a third-party programmer or CODEGRIP/mikroProg connected to onboard JTAG/SWD header, the UNI Clicker board also includes a clean and regulated power supply module for the development kit. It provides two ways of board-powering; through the USB Type-C (USB-C) connector, where onboard voltage regulators provide the appropriate voltage levels to each component on the board, or using a Li-Po/Li
Ion battery via an onboard battery connector. All communication methods that mikroBUS™ itself supports are on this board (plus USB HOST/DEVICE), including the well-established mikroBUS™ socket, a standardized socket for the MCU card (SiBRAIN standard), and several user-configurable buttons and LED indicators. UNI 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.
Microcontroller Overview
MCU Card / MCU
Type
8th Generation
Architecture
ARM Cortex-M0
MCU Memory (KB)
128
Silicon Vendor
STMicroelectronics
Pin count
100
RAM (Bytes)
16384
You complete me!
Accessories
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.
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the UNI Clicker as your development board.
Track your results in real time
Application Output
After loading the code example, pressing the "DEBUG" button builds and programs it on the selected setup.
After programming is completed, a header with buttons for various actions available in the IDE appears. By clicking the green "PLAY "button, we start reading the results achieved with Click board™.
Upon completion of programming, the Application Output tab is automatically opened, where the achieved result can be read. In case of an inability to perform the Debug function, check if a proper connection between the MCU used by the setup and the CODEGRIP programmer has been established. A detailed explanation of the CODEGRIP-board connection can be found in the CODEGRIP User Manual. Please find it in the RESOURCES section.
Software Support
Library Description
This library contains API for RFID Click driver.
Key functions:
rfid_select_communication_interface- Select communication interfacerfid_get_tag_uid- Get RFID tag uid functionrfid_get_device_id- RFID get device id function
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 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
