CH340

CH340G USB-to-Serial Adapter

The CH340G is a low-cost USB-to-Serial (UART) bridge chip developed by WCH (Nanjing QinHeng Microelectronics). It enables communication between USB-equipped computers and devices with UART interfaces, such as embedded systems and microcontrollers. Widely used in development boards like Arduino clones, the CH340G is favored for its affordability and reliability.

Features

• 🔌 USB 2.0 Full-Speed Interface: Supports data transfer rates up to 12 Mbps.
• ⚡ Voltage Compatibility: Operates at both 3.3V and 5V (configurable), accommodating various logic levels.
• 🧰 Minimal External Components: Requires only a crystal oscillator and a few capacitors for operation.
• 💾 Driver Support: Compatible with Windows, macOS, and Linux operating systems.
• 🔄 Standard UART Interface: Provides TXD, RXD, RTS, and CTS signals for serial communication.
• 🧱 Compact Package: Available in SOP-16 package, suitable for space-constrained applications.

Pinout

Pin Number	Name	Description
1	VCC	Power supply input (3.3V or 5V)
2	GND	Ground
3	TXD	Transmit data output
4	RXD	Receive data input
5	RTS	Request to send output
6	CTS	Clear to send input
7	DTR	Data terminal ready output
8	DSR	Data set ready input
9	RI	Ring indicator input
10	DCD	Data carrier detect input
11	XI	Crystal oscillator input
12	XO	Crystal oscillator output
13	UD+	USB D+ signal
14	UD-	USB D- signal
15	RESET	Reset input
16	NC	No connection

Applications

• 🛠️ Firmware Uploading: Used to program microcontrollers via UART bootloaders.
• 🖥️ Serial Debugging: Facilitates communication with serial consoles for debugging purposes.
• 🔧 Device Modding: Enables interfacing with UART ports on various hardware for customization.
• 📡 Sensor Data Logging: Collects data from serial-output sensors for analysis.

Driver Installation

• Windows: Requires installation of the CH340 driver from the manufacturer's website.
• macOS: Compatible with macOS 10.9 and later; driver installation may be necessary.
• Linux: Supported natively by most distributions; the `ch341` kernel module handles the device.

Troubleshooting Tips

• 🔌 Connection Issues: Ensure correct wiring of TXD and RXD lines; they should be cross-connected.
• ⚠️ Driver Conflicts: Uninstall conflicting drivers that may interfere with CH340G operation.
• 🔁 Loopback Test: Short TXD and RXD to test the adapter's functionality by checking for echoed data.

External Resources

• [Official CH340G Datasheet (PDF)](https://www.alldatasheet.com/view.jsp?Searchword=CH340G)
• [WCH Official Website](http://wch.cn)
• [CH340G Driver Downloads](http://www.wch.cn/downloads/CH341SER_EXE.html)