[Solved] TYWE3S (ESP8266EX) - Button press not detectable

[Update]

Solution: as ever, the problem was in front of the keyboard... I simply forgot to put a "pinMode(LED, OUTPUT);" in the setup() for the LED indicating button presses. Argh!

Hi,

I am analyzing an outdoor dual power plug currently to put my own firmware on it. It is controlled by a TYWE3S module, that is an incarnation of an ESP8266EX with 1M of flash.

I got the official TYWE3S specs from here: TUYA. The pinout names pin numbers, the corresponding GPIO names etc.

I am using the Arduino IDE to program the beast. I found that the pin numbers the TUYA page gives are not the same as in the IDE. I measured the board to find connections and looked at the traces under a microscope.

These are my findings:

So some pins are matching the specs, like 1(TUYA)=1(Arduino)=TXD0, 2(TUYA)=2(Arduino)=RXD0. 3(TUYA) is identifyable as LED port, TUYA calls it GPIO5, but on Arduino it is pin 5!

Anyway, I found all LED and relay ports finally.

The problem that remains is the button on the board. With the meter I found that the button pulls pin 12(TUYA)=GPIO14 to GND. But I was not able yet to find the Arduino pin number for it - I checked everything between 1 and 16 to no avail.

Does anyone of you have had come across this before? Any ideas of how to solve it?