esp-idf-rc522

C library for interfacing ESP32 with MFRC522 RFID card reader, packaged as ESP-IDF component.

Note

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