Blink Manual Flash


This will be the first example. Let’s start with an easy one.
Let’s blink a led.

This Example explains blink. By using a USB-TTL connector that only can send and retrieve (have only RX and TX). If your USB-TTL connector support DTR and Reset (RST) than use this example. It reduces the example with 2 buttons and makes the upload (flash) much easier.

Shopping list
– 1 ESP8266 (for example version ESP01)
– 1 led (I use a red one)
– 1 USB to TTL (I use FT232RL)
– 2 push buttons
– 10 wires
– 1 breadboard
– a 3.3V power source (I use an battery in this example, power from your USB TTL will most likely might NOT work)

TTL to ESP01 blink upload and reset button


+3.3V — CH_PD
pushbutton — GPI0
resetbutton — RST
battery – — GND
battery + — VCC
led,longleg — GPIO2
led,shortleg — GND

Actually this is the same example as you may find in Files->Examples->01 Basics-> Blink.
ledPin = 2 means that we are using GPIO2.

int ledPin = 2;
void setup() {
pinMode(ledPin, OUTPUT);

void loop() {
digitalWrite(ledPin, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(ledPin, LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second


Press reset button while holding flash button pressed. In other words. Press flash button, keep the flash button pushed while you once click on reset. You may now release the flash button. The ESP8266 is now in flash mode. You are able to upload the sketch.
Press upload in the Arduino IDE, arduino will compile and upload. After the sketch is uploaded, the led will blink for one second on and off.

When you have uploaded the sketch, you may remove all the wires required for uploading.
This is what is left.

ESP8266 ESP01 blink

10 thoughts on “Blink Manual Flash

  1. If you would like to use your arduino UNO to upload your sketch, when you do not have a USB-TTL. It is possible, Just connect RX to RX and TX to TX. (instead of RX to TX and TX to RX)

    1. I tried to use arduino UNO to upload the sketch, by the ide gives me the error espcomm_open failed.
      I tried different programmer modes and different speeds without any result. hints?

    2. Hi admin, i used your method without USB-TTL and connecting rx to rx, and the file could upload, but the led did not blink using the blink sketch, it just stay litted up, what should i do?

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