esp-idf-rc522

C library for interfacing ESP32 with MFRC522 RFID card reader.

Library currently just reads serial number of RFID tags, which is enough for most applications.

How to use

This directory is an ESP-IDF component. Clone it (or add it as submodule) into components directory of the project.

Example

This is basic example of scanning RFID tags.

#include <esp_log.h>
#include <inttypes.h>
#include "rc522.h"

static const char* TAG = "rc522-demo";
static rc522_handle_t scanner;

static void rc522_handler(void* arg, esp_event_base_t base, int32_t event_id, void* event_data)
{
    rc522_event_data_t* data = (rc522_event_data_t*) event_data;

    switch(event_id) {
        case RC522_EVENT_TAG_SCANNED: {
                rc522_tag_t* tag = (rc522_tag_t*) data->ptr;
                ESP_LOGI(TAG, "Tag scanned (sn: %" PRIu64 ")", tag->serial_number);
            }
            break;
    }
}

void app_main()
{
    rc522_config_t config = {
        .spi.host = VSPI_HOST,
        .spi.miso_gpio = 25,
        .spi.mosi_gpio = 23,
        .spi.sck_gpio = 19,
        .spi.sda_gpio = 22,
    };

    rc522_create(&config, &scanner);
    rc522_register_events(scanner, RC522_EVENT_ANY, rc522_handler, NULL);
    rc522_start(scanner);
}

FAQ

How to use I2C instead of SPI?

Set the property .transport of the config structure to RC522_TRANSPORT_I2C and choose GPIOs for data (.i2c.sda_gpio) and clock (.i2c.scl_gpio):

rc522_config_t config = {
    .transport = RC522_TRANSPORT_I2C,
    .i2c.sda_gpio = 18,
    .i2c.scl_gpio = 19,
};

How to use halfduplex in SPI transport?

Set the .spi.device_flags property of the config to SPI_DEVICE_HALFDUPLEX. Other device flags (SPI_DEVICE_*) can be set here as well by chaining them with bitwise OR (|) operator.

rc522_config_t config = {
    .spi.host = VSPI_HOST,
    .spi.miso_gpio = 25,
    .spi.mosi_gpio = 23,
    .spi.sck_gpio = 19,
    .spi.sda_gpio = 22,
    .spi.device_flags = SPI_DEVICE_HALFDUPLEX,
};

How to attach RC522 to existing SPI bus?

Let's say that spi bus VSPI_HOST has been already initialized, and rc522 needs to be attached to that bus. That can be accomplished with the next configuration. Property .spi.bus_is_initialized is required to be set to true in order to inform library to not initialize spi bus again.

NOTE: Property .spi.bus_is_initialized will be deprecated in the future once when this issue is resolved.

rc522_config_t config = {
    .spi.host = VSPI_HOST,
    .spi.sda_gpio = 22,
    .spi.bus_is_initialized = true,
};

Author

GitHub: abobija
Homepage: abobija.com

License

MIT