ESP8266 Community Forum

- Wed Oct 19, 2016 5:09 pm #56807 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

- Fri Dec 02, 2016 2:44 pm #59020 Hello, in order to use many devices with SPI you can use same hardware MOSI MISO CLK...
You need to define different SS for each device.

Should work, i'm using SSD1306 + RC522 at the same time both with SPI on ESP8266