GPIO14 pin (D5) not working

[anidh1997]

Hi everyone,

I am using NodeMCU Amica. It has UART communication with GPS sensor, pin D5(Rx) is connected the GPS_TX and getting data with SoftwareSerial library. The problem coming is, If I connect the power to NodeMCU when the UART pin is connected, the data does not comes. But if the UART pin is connected after connecting the power to NodeMCU, the data comes. This problem is not at the other pins of NodeMCU (Eg. D2). Are there some specifications related to D5 pin?

The pin-name of D5 is MTMS as given in NodeMCU ESP8266 datasheet.

I checked the schematic "NODEMCU_DEVKIT_V1.0.PDF" in this GitHub page and found MTMS written in red (please see the attached picture) but unable to understand what it means.

If anyone knows about the above problem please help.

[jcallano]

You can read this article that investigates the state and behavior of each GPIO on boot:

https://rabbithole.wwwdotorg.org/2017/03/28/esp8266-gpio.html