ESp8266 ESP-12-E
The ESP-12E has a ESP8266 core processor, with a module of 4MB of flash memory. Also it has 22 pins and a on board printed antenna. It also has a built-in LED which is directly connected to the UART TX line. You can use the TX pin as GPIO1 to control the LED, but only if you don't use UART.
ESP8266 Bootloader Modes
The bootloader can go into a number of modes depending on the state of GPIOs 0, 2 and 15. The two useful modes are the UART download mode (for flashing new firmware) and the flash startup mode (which boots from flash).
| Mode | GPIO0 | GPIO2 | GPIO15 |
|---|---|---|---|
| UART Download Mode (Programming) | 0 | 1 | 0 |
| Flash Startup (Normal) | 1 | 1 | 0 |
| SD-Card Boot | 0 | 0 | 1 |
CH_PD (or EN) Chip enable. Should be high for normal operation.
Wiring the ESP8266 Chip
Dev Boards
| Board | Info | Layout |
|---|---|---|
ESP8266 Thing Dev | https://www.sparkfun.com/products/13711 PROS: External antenna connection. Serial Driver: Cost: $15 US |
|
| WeMos D1 Mini | https://wiki.wemos.cc/products:d1:d1_mini PROS: Shields available Serial Driver: CH34x Cost: $3.25 US |
|
| Node MCU Lolin | https://frightanic.com/iot/comparison-of-esp8266-nodemcu-development-boards/ PROS: Exposes extra pins. Serial Driver: Cost: $3.30 US |
|
References
| Reference | URL |
|---|---|
| ESP-12E | https://github.com/lvidarte/esp8266/wiki/ESP%E2%80%9012E |
ESP8266 Thing Development Board Hookup Guide | https://learn.sparkfun.com/tutorials/esp8266-thing-development-board-hookup-guide/all |