a library to use mfrc522 with uart in esp8266 or arduino .
first add the .cpp and .h file to your library in arduino IDE. then create a MFRC522WITHUART instance in main.c then you can use the library.
I used https://github.com/miguelbalboa/rfid ,however, I just changed writeregister and read register plus a little init function but other parts remained untouched I tested it myself and I can read serial from Tag
I tested the reader module and found out that this module could not read Tag serial with baud rate less than 14400 currently i setup baud rate to 115200 but if you want to change it you have to modify the .cpp file in line 234,235 and 267,268 based on Mfrc522 datasheet section 8.1.3.2
PCD_WriteRegister(SerialSpeedReg, 0x7A);
_serialClass->begin(115200);
I used main esp8266 uart to communicate with module as uart1 cant be used because it's rx pin already been used in esp8266 module for flash so i deided to use uart1 in tx only mode to debug programm and hence all "Serial1.println" or "Serial1.print" in "MFRC522WITHUART.cpp" and "example.ino" file are used for debugging and you can comment them all without worrying about performance. just keep in mind that unplug rx and tx while you are downloading to flash because UART0 is the only way to download the flash so you may have error
I used Wemos D1 module that utilizes esp8266 and mfrc522 module Reader Module is by default working with SPI and so consider you have to do some modification in your reader module in order to use UART instead of SPI
| RC522 | Device |
|---|---|
| SDA | TX |
| MISO | RX |
| 3.3V | 3.3V |
| GND | GND |
