After asking How to connect Arduino & ESP8266, I tried to build such circuit.
First I tried the code one 2 Nano's - to verify 2 MCU sending and receiving messages. After that, I started to build the following circuit:
Take1: MCU A: Arduino Micro 5V, MCU B: WEMOS mini.
Take2: MCU A: Arduino Micro 5V, MCU B: WEMOS mini.
Take3: MCU A: Arduino NANO ,MCU B: WEMOS mini.
Take4: MCU A: Arduino NANO 5V, MCU B: WEMOS mini.
Rx (no vdiv ). OK
Edit1: LCD display is connected to MCU B ( as it was tested using 2 Nano ) via I2C. Messages received are sent to LCD. PLEASE IGNORE LCD shown in not I2C
Diagram updated - GND was missing and POWER IN clarification.
LCD display is an I2C one. It shows properly WEMOS is booting up properly ( shows a boot msg ), and spits every incoming
Serialmessage from other MCU. When TAKE4 and TAKE1 were taken, setup and code worked PROPERLY.
What is done wrong?