The ESP8266(Wikipedia) chip is an affordable Ardunio compatible and WiFi enabled microprocessor. From the several modules out there this note selects the ESP8266-12 one, which features up to 12 I/O pins. Although there is a lot of information on the around the ESP8266, it was a kind of hard to figure out correct wiring for an initial setup. With the help of ESP8266 Community Wiki I ended up with the following wiring:
- GND –> GND (LOW)
- GPIO15 –> GND (LOW; this is required for the ESP-12 module)
- GPIO0 –> floating (disconnect; need pulled to GND (LOW) for reprogramming)
- RXD –> TX of the FTDI (serial to USB UART ) module
- TXD –> RX of the FTDI module
- VCC –> 3.3V (HIGH)
- CH_PD or EN –> 3.3V (HIGH)
- RST –> 3.3V (HIGH)
Most documentation refers to CH_PD pin, but that pin was labeled as EN on my board
For successful operation there is also a reliable 3.3V power source required. In my experience powering the ESP from the FTDI module did not work for me.