ESP8266 Community Forum

- Tue Dec 08, 2015 3:07 am #35954 Ok, here are my findings after having purchased a logical analyser:

On LUA mode,
- when connecting the output of my sensor to NodeMCU PIN GPIO13 (RXD2): I can see the UART signal applied on this PIN but ESP8266 is not reading it
- when connecting the output of my sensor to NodeMCU PIN GPIO3 (RXD0): I can't see the UART signal on this PIN, the voltage remains high all the time

So my conclusion: in LUA mode, since Serial.swap() is not available AFAIK, should I want to access UART information from my ESP8266, I probably have only one option: disconnect the USB cable from the ESP8266 in RUN mode. However, this would make my life a nightmare when troubleshooting, since I lose of course the printf fonctions...

As a consequence, I switched to Arduino IDE and am now using Serial.swap(). Works like a charm.

- Mon Oct 31, 2016 11:14 pm #57475 Please, could you share your code?
I have an old RDM6300 RFID module that sends tags reading through serial --- it works fine in Arduino SoftwareSerial. I would like to make NodeMCU read through serial PIN13 (?) and send in an URL http call.

Thanks,

- Wed Nov 23, 2016 6:13 am #58554 Have you successfully worked with Serial.swap()?

- Sat Feb 04, 2017 10:48 pm #62055

Ok, here are my findings after having purchased a logical analyser:

On LUA mode,
- when connecting the output of my sensor to NodeMCU PIN GPIO13 (RXD2): I can see the UART signal applied on this PIN but ESP8266 is not reading it
- when connecting the output of my sensor to NodeMCU PIN GPIO3 (RXD0): I can't see the UART signal on this PIN, the voltage remains high all the time

So my conclusion: in LUA mode, since Serial.swap() is not available AFAIK, should I want to access UART information from my ESP8266, I probably have only one option: disconnect the USB cable from the ESP8266 in RUN mode. However, this would make my life a nightmare when troubleshooting, since I lose of course the printf fonctions...

As a consequence, I switched to Arduino IDE and am now using Serial.swap(). Works like a charm.

Hi beetlejuice76, could you kindly show the code that you successfully did in Arduino? Need some help here thanks!!