In previous article, we have seen how to talk to a 8266 thru serial.
We could do the same from an arduino and therefore use this module as a slave.
But why introduce a second MCU when the ESP8266 itself is a MCU?
Our arduino IDE can actually program such a MCU (next to the atmega series).
For this you will need latest arduino ide (version 1.6.4 and up).
You will also need to add support for the ESP8266 : see here how to do this.
Once done you are ready to program your MCU.
Dont forget to pull GPIO0 down but also to reset your MCU when entering the flash phase (or else you’ll get « error: espcomm_open failed »).
Once flashed, set GPIO0 free.
See below our arduino ide flashing the blink demo.