Low-cost USB to UART bridge. Found on Arduino clone boards, needs CH340 driver.
| Pin | Name | Function | Type |
|---|---|---|---|
| 1 | GND | Ground | GND |
| 2 | TXD | UART transmit output | BUS |
| 3 | RXD | UART receive input | BUS |
| 4 | V3 | Internal 3.3V for USB | PWR |
| 5 | UD+ | USB D+ differential | BUS |
| 6 | UD- | USB D- differential | BUS |
| 7 | XI | Crystal input | I/O |
| 8 | XO | Crystal output | I/O |
| 9 | CTS | Clear to send | I/O |
| 10 | DSR | Data set ready | I/O |
| 11 | RI | Ring indicator | I/O |
| 12 | DCD | Data carrier detect | I/O |
| 13 | DTR | Data terminal ready | I/O |
| 14 | RTS | Request to send | I/O |
| 15 | VCC | 5V supply | PWR |
| 16 | GND | Ground | GND |
The CH340G is a low-cost USB-to-UART bridge IC by WCH. It creates a virtual COM port and is the USB chip used on many cheap Arduino clones and USB-to-serial adapters. Requires driver installation on some systems.