Cannot perform UART - Communication using ESP8266


If you are asking a question, please follow this template:

  1. My goal is: Using esp32 and selecting the UART interface 1, I can do successfully communicate with another UART device.

  2. My actions are: The Same I am not able to do it using ESP8266. Tried using UART1 and UART2 interfaces of ESP8266, My UART code is the same for both ESP32 and ESP8266, I am just building for different platforms and selecting different UART interfaces of the microcontrollers.

  3. The result I see is: My other UART enabled device is not performing as per the same UART instruction when I try to communicate using ESP8266 but the same UART device will perform as per instruction when I use ESP32 with UART interface 1.

  4. My expectation & question is: How do I achieve this using ESP8266.

side note: My UART connections are alright.

If anyone knows please let me know how to achieve it.


Only UART0 has rx and tx on ESP8266. UART1 has only tx and UART2 does not exist.


@nliviu Thank you for your replay, Yes I am able to do UART communication (Using UART Interface 1), but I want to know what is RXD2 (GPIO 16, on development board represented as D7) and TXD2 (GPIO 17, on development board represented as D8), because of these I thought ESP8266 has three UART interfaces.


Lokesh CJ


Did you check your specific board datasheet for the proper definition of those names and which pin they are routed to in the board; and then the ESP8266 chip datasheet for the proper definition of those pins and the GPIO routing capabilities ?