ESP8266 Community Forum

- Sat Oct 03, 2015 6:03 pm #30440 So I got a RC522 wired up to the NodeMCU 0.9 like this:

SDA > D4 (GPIO02), SCK > D5 (GPIO14), MOSI > D7 (GPIO13), MISO > D6 (GPIO12), GND > GND, RST > D8 (GPIO15), 3.3V > 3.3V

https://github.com/Jorgen-VikingGod/ESP8266-MFRC522 using the sketch here but I dont get anything in serial.

Neither can I flash it when the RC522 is connected to the breadboard.

Also I have tried to solder up a second RC522 and connect it with the same issues.

Does anyone have a idea?

- Sun Oct 04, 2015 6:20 am #30461 Hi There!

Yes it does that.
I figured out that you cannot use GPIO15 for RST.
Just connect it to somewhere else (GPIO4 for example, change it in the code: #define RST_PIN 4) and it will work like a charm.
Also reading the tags works without having RST connected.
Tested this with NODEMCU 1.0 just today.

Br, Jozsef

- Tue Oct 06, 2015 2:25 pm #30685

So I got a RC522 wired up to the NodeMCU 0.9 like this:

SDA > D4 (GPIO02), SCK > D5 (GPIO14), MOSI > D7 (GPIO13), MISO > D6 (GPIO12), GND > GND, RST > D8 (GPIO15), 3.3V > 3.3V

https://github.com/Jorgen-VikingGod/ESP8266-MFRC522 using the sketch here but I dont get anything in serial.

Neither can I flash it when the RC522 is connected to the breadboard.

Also I have tried to solder up a second RC522 and connect it with the same issues.

Does anyone have a idea?

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- Wed Oct 19, 2016 3:27 pm #56796 Hello friends I'm new to developing with esp8266, I'm trying to connect both an RFID reader rc522 and screen nextion 2.4 "in a NodeMCU 1.0, using arduino IDE v 1.6.11 to read an RFID tag and display the UID in Nextion 2.4 screen ".

I managed to connect and work with each separately, but I can not make them work together.

when the connections operate separately in NodeMCU v 1.0 are the following:

Nextion 2.4 "||| MCU Node 1.0

5V-------------- 5V
RX ------------ (D7) - GPIO13 - RXD2 - HMOSI
TX ------------ (D8) - GPIO15 - TXD2 - HCS
GND ----------GND

RC522 ||| MCU Node 1.0

3.3V------ 3.3V
RST ------ (D2) - GPIO4
GND------- GND
IRQ -----
MISO -------(D6) - GPIO12 - HMISO
MOSI -------(D7) - GPIO13 - RXD2 - HMOSI
SCK --------(D5) - GPIO14 - HSCLK
SS ----------(D4) - GPIO2 - TXD1

Both devices need to use the pin D7 (RXD2), I would like to use both at the same time, I read that I use UART but do not understand how to apply.

any help is welcome
thank you very much