MEAM.Design - ESP8266 - Board Pinout & Functionality
"Pinout of ESP8266 from alexbloggt.com
Left Side
| A0 | ADC0 | Analog to Digital Converter |
| TOUT | pin-change interrupt, channel 0 | |
| RSV | Reserved | Unused pin |
| RSV | Reserved | Unused pin |
| SD3 | GPIO10 | General Purpose Input/Output 10 |
| SDD3 | ||
| SD2 | GPIO 9 | General Purpose Input/Output 10 |
| SDD2 | ||
| SD1 | MOSI | SPI Master Out Slave In |
| SDD1 | ||
| CMD | CS | SPI Chip Select |
| SDCMD | ||
| SD0 | MISO | SPI Master In Slave Out |
| SDD0 | ||
| CLK | SCLK | SPI Clock |
| SDCLK | ||
| GND | GND | Ground |
| 3V3 | 3.3V | Regulated 3.3V Source |
| EN | EN | |
| RST | RST | Reset |
| GND | GND | Ground |
| Vin | Vin | Power for the board, usually 5V (when connected to USB, you should disconnect this power source) |
Right Side
| D0 | GPIO16 | General Purpose Input/Output 16 |
| USER | ||
| WAKE | ||
| D1 | GPIO5 | General Purpose Input/Output 5 |
| D2 | GPIO4 | General Purpose Input/Output 4 |
| D3 | GPIO0 | General Purpose Input/Output 0 |
| FLASH | analog-to-digital converter, channel 4 | |
| D4 | GPIO2 | General Purpose Input/Output 2 |
| TXD1 | ||
| 3V3 | 3.3V | Regulated 3.3V out |
| GND | GND | Ground |
| D5 | GPIO14 | General Purpose Input/Output 14 |
| HSCLK | ||
| D6 | GPIO12 | General Purpose Input/Output 12 |
| HMISO | H Master In Slave Out | |
| D7 | GPIO13 | General Purpose Input/Output 13 |
| HMOSI | H Master Out Slave In | |
| RXD2 | Receive 2 | |
| D8 | GPIO15 | General Purpose Input/Output 15 |
| HCS | H Chip Select | |
| TXD2 | Transmit 2 | |
| Rx | GPIO3 | General Purpose Input/Output 3 |
| RXD0 | Receive 0 | |
| Tx | GPIO1 | General Purpose Input/Output 1 |
| TXD0 | Transmit 0 | |
| GND | GND | Ground |
| 3V3 | 3.3V | Regulated 3.3V out |