ESP8266 Community Forum

- Thu Nov 07, 2019 3:19 pm #84463 How RC522 can be connected to ESP8266 using UART instead of using SPI. SPI requires more pin which can be done using nodemcu board. But in case of ESP01 which has only 2 IO pin, cannot be connected to RC522. Please help if anyone has solution.

Note that I made RC522 work with nodemcu using SPI. I also worked with RDM6300 RFID reader with UART. But I need UART for RC522 RFIF module.

- Fri Nov 08, 2019 8:12 am #84478 An ESP8266 has 2 UARTs: one complete one (UART0), and another you can only use the TX of (UART1).

On the ESP-01 UART0 is available on pins 4 (RX) and 5 (TX): they're the exact ones you use to flash an ESP, but can also be used in your projects to communicate to other UARTs (at 3.3V level).

Assumption is the mother of all f*ckups. At least: that's what I'm assuming.