Ok, sory friend, so look:
This is my schematic:
And what is the problem :
ESP8266 Nodemcu V2 : RX - pin 20, TX - pin 21
ARDUINO UNO - RX pin 1, TX - pin 0
Two connection wire :
-connection one : pin 0 with pin 20
-connection two : pin 1 with pin 21
Send data from ESP8266 to UNO - working ok via connection two
Send data from UNO to ESP8266 - not working ! via connection one
When i change the wires and pins :
-connection one : pin 0 with pin 21 (tx - tx) - when i send data from UNO to ESP8266 , data send are good. IT's working
-but connection two - pin 1 with pins 20 - not working .
ALWAYS, when i use to transmit data via pins 20 on esp8266, always it isn't working...nothing
when i use a pin 21 on ESP8266, to send or receive data, it's working good... so strange .. everything is ok but no pins/port number 20 on ESP8266.
I need transmit data in both side, so i need a pin RX and TX on esp8266.. pin 21(TX) isn't enough....
I think that it is so weird, because, it can see like a broken pin RX on Esp8266, but i tried a another ESP8266 and it is the same problem...