How to prepare your ESP8266 (ESP-12) for flashing

The use of an ESP version of the ESP8266 (e.g. ESP-12e, ESP-12f, ESP-12s, …) offers some advantages over the developer boards like the NodeMCU or the WeMos D1 Mini (and many other compatible boards). With this tutorial you will see how to wire the ESP8266 in order to program (flash) it.

Here are the two most important ones:

  • The ESP12 is more compact and more affordable
  • It has a lower power consumption (even in normal operation), due to the missing extra components, which are often not needed in daily operation – such as the USB to serial converter or the 5V to 3.3V voltage regulator.

Of course, this does not only mean advantages: To install firmware on it you need a USB to serial adapter (e.g. this one here), and some resistors (depending on the variant 2 or 5 pieces with about 10kΩ) to get the chip into the right operating mode.

But then you will be rewarded with completely new possibilities, e.g. the option to operate the chip in “Deep Sleep Mode” – whereby you reduce the power consumption significantly, and thus enable a satisfactory battery-powered operation.

Original ESP-12 without adapter board

How to flash program an ESP8266 (ESP-12) without adapter board
In this drawing you can see the ESP-12 chip (by the way: variants of it like the ESP-07 with antenna connector often have the same pin assignment), and how it is prepared with the help of 5x 10kΩ resistors for normal operation, as well as the flash mode.

If you want to install the Sensate firmware on the chip, you just have to close the switch (you can realize it with a jumper or a wire bridge) and disconnect the power supply of the ESP-12. Alternatively you can also install a reset switch (from RST to ground).

Once you have done this, the ESP is in flash mode, and can now be played as described in Firmware-Guide.

Original ESP-12 on adapter board

How to flash program an ESP8266 (ESP-12) on an adapter board
In this drawing you can see the ESP-12 chip (by the way: variants like the ESP07 with antenna connector often have the same pin assignment), which was soldered to an adapter board. Since the adapter is already equipped with some resistors, you only need two 10kΩ resistors for normal operation and flash mode.

If you want to install the Sensate firmware on the chip, you just have to close the switch (you can realize it with a wire bridge or a jumper) and disconnect the power supply of the ESP-12. Alternatively you can also install a reset switch (from RST to ground).

Once you have done this, the ESP is in flash mode, and can now be played as described in Firmware-Guide.

NodeMCU, WeMos D1 Mini (and others)

These developer boards already have everything necessary on their board and can therefore be connected directly to the computer with a Micro-USB cable. Switching to flash mode is not necessary here, the electronics of these boards do this automatically.

And now…?

Check out our Tutorials, some of them use exactly these chips!