| 1 | RST | Reset (Active Low) |
| 2 | ADC (A0) | Analog Input (0–1V) |
| 3 | EN (CH_PD) | Chip Enable (Pull High for Normal Operation) |
| 4 | GPIO16 | Wake from Deep Sleep, General Purpose I/O |
| 5 | GPIO14 | SPI_CLK, General Purpose I/O |
| 6 | GPIO12 | SPI_MISO, General Purpose I/O |
| 7 | GPIO13 | SPI_MOSI, General Purpose I/O |
| 8 | VCC | 3.3V Power Supply |
| 9 | GND | Ground |
| 10 | GPIO15 | SPI_CS, Boot Mode Selection (Pull Low for Normal Operation) |
| 11 | GPIO2 | Boot Mode Selection, General Purpose I/O |
| 12 | GPIO0 | Boot Mode Selection (Pull Low for Flash Mode) |
| 13 | GPIO4 | I²C SDA, General Purpose I/O |
| 14 | GPIO5 | I²C SCL, General Purpose I/O |
| 15 | RXD (GPIO3) | UART0 RX, General Purpose I/O |
| 16 | TXD (GPIO1) | UART0 TX, General Purpose I/O |
