I am using esp8266-01 board. It was working fine few days ago, the codes uploaded and ran successfully. But now that I upload code to it, it gets uploaded successfully but it doesn't work.

I am using arduino nano to program it. It is connected as: esp-01 arduino nano tx-------------tx rx-------------rx vcc------------3v3 ch_pd----------3v3 gpio0----------gnd gnd------------gnd

the code is basic blink code:

void setup(){
   pinMode(2, OUTPUT);
void loop(){
   digitalWrite(2, HIGH);
   digitalWrite(2, LOW);

This code gets uploaded successfully (According to IDE atleast) but it doesn't run. LED connected to gpio2 is always on. I also tried gpio0 and gpio1 but no luck.

I have already spend days trying to fix this. Please Help.

  • pull-up io 0 to run. io 0 LOW at reset always starts flashing mode. io 2 must be not LOW at startup – Juraj Jan 31 '20 at 16:09

if you are using a nodemcu, the pin numbers do not correspond to the digital pins, they correspond to the gpio pins. The digital pin 2 is the gpio 4 and the digital pin 4 is the gpio 2. Here you have a list of digital and gpio pins:

D0 = GPIO16;
D1 = GPIO5;
D2 = GPIO4;
D3 = GPIO0;
D4 = GPIO2;
D5 = GPIO14;
D6 = GPIO12;
D7 = GPIO13;
D8 = GPIO15;
D9 = GPIO3;
D10 = GPIO1;
  • the title has esp-01 – Juraj Feb 2 '20 at 5:56
  • The RST pin is high? If it is low the board resets – URROVA Feb 2 '20 at 14:25
  • with reset pin LOW upload would not work – Juraj Feb 2 '20 at 14:49
  • 1
    Thank you for answering. But I have mentioned that i am using esp01 board – BinitPoddar Feb 3 '20 at 8:11

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