While working on my recent ESP8266 project I discovered that it's pretty hard to find a breadboard adapter that has all the pins from ESP-12 E / F modules available. I really needed the SPI interface but common cheap adapters do not allow to use it.
After some research I decided to design a new adapter myself. My goal was not only access all the ESP-12 E / F pins on a regular breadboard but also to improve overall breadboard adapter experience. Therefore:
- Adapter allows to access every single pin of ESP-12 module. That includes SPI interface and GPIO9 / GPIO10 available on ESP-12 E and F versions.
- It’s ready for optional THT pull-up / pull-down resistors for RESET, CH_PD, GPIO0, GPIO2 and GPIO15 pins. That saves space on a breadboard for the part of the design that is unique also making reset and flash mode switches circuits as easy as possible. If you choose not to use pull-ups / pull-downs then the pins are simply directly broken out to the breadboard. THT (Through-Hole Technology) was chosen for resistors to make DIY soldering easier.
- Small size - only 16 rows of breadboard is occupied.
- All signals are available at uncovered breadboard tie points. As a result you don’t need to route all signals before plugging adapter into breadboard or remove adapter to route a new signal.
After some consideration I also decided what should not be included onboard:
- No voltage regulator since you probably can’t choose one voltage regulator for all your future designs.
- No FTDI like interface since you probably won’t include this in your final design - it’s more economical to use one serial port interface for all your designs.
The result is (IMHO) a fully featured breadboard adapter that includes only components usually present across all ESP designs (but even these are optional) and puts absolutely no constrains on your project.
I created full documentation for my project. It's available at: http://www.cielecki.pl/docs/esp12-breadboard-adapter/
My design turned into real thing using professional PCB service. Since you cannot order one board only I have some spare PCBs. I listed these items on eBay so if some is interested please visit:
https://www.ebay.com/itm/164350746552 (new listing from August 2020: last 3 adapters)
(eBay offer includes PCB, pull-up / pull-down resistors and pinheaders for soldering)
I attached some pictures of the board, adapter with all the elements soldered and diagrams of the pin layouts.
If you have same questions and comments about my design don't hesitate to write here.