On the web we can find differents ways to program a ESP-8266 but in this post I’ll show you what way it works for me.

Prerequisites

• You will need a TTL to USB interface (for example FTDI FT232RL) or you could use the Arduino Uno. In this post we’ll use the Arduino UNO.
• The Arduino IDE configured for working with ESP-8266. There are a lot of tutorials about this.

ESP-8266 in programing mode

Steps to connect:

1. Connect TX to RX
2. Connect RX to TX
3. Connect VCC and CH-PD to +
4. Connect GND and GPIO0 to - Run the Arduino IDE and before upload the code you must change to programming mode:
5. Connect and disconnect Reset to -. You will can see a blue light in the ESP-8266 that will indicate that you are in programming mode.

Arduino UNO

With arduino you could use the 3,3V as +, the GND as -, and the ports RX and TX for the transfer.

NOTE: It’s important that you connect permanently the reset port to - in Arduino for program the ESP-8266.

Custom Programmer

I’ve built with a board a programmer with a reset button that will ease the steps indicated before. This is the result.