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Overview of CH340 USB Converter Chip

CH340 is a USB bus convert chip. It allows the USB to be converted to serial interface, serial signals to USB etc. This article mainly covers datasheet, pinout, circuit, diagram, application, and other details about the CH340 USB driver converter chip. Furthermore, there is a huge range of semiconductors, capacitors, resistors, and Ics in stock. Welcome your RFQ!

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Sep 19, 2021

Theodore Benson

Driver CH340 | USB to Serial

 

CH340 is a USB bus convert chip. It allows the USB to be converted to serial interface, serial signals to USB etc. This article mainly covers datasheet, pinout, circuit, diagram, application, and other details about the CH340 USB driver converter chip. Furthermore, there is a huge range of semiconductors, capacitors, resistors, and Ics in stock. Welcome your RFQ!

CH340G

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CH340 Pinout

CH340 Pinout

Pin   Number Pin Name Description
1 CKO Clock output
2 ACT Negative phase clock   output
3 TXD Serial data output
4 RXD Serial data input
5 V3 External 3.3V supply
6 UD+ USB data positive
7 UD- USB data negative
8 GND IC ground reference
9 XI External crystal pin
10 XO External crystal pin
11 CTS Clear to send signal   pin
12 DSR Data set ready pin
13 RI Ring indicator pin
14 DCD Data carrier detect   pin
15 DTR Data terminal ready   pin
16 RTS Request to send pin
17 NC Not connected
18 R232 RS232 enable
19 VCC Power input
20 NOS Forbid USB device   suspending pin

What is CH340?

CH340 is a USB bus convert chip that can convert USB to serial, USB to IrDA infrared, or USB to printer interface.

In serial interface mode, the CH340 provides a common MODEM liaison signal, which can be used to expand a computer's asynchronous serial interface or immediately upgrade a common serial device to the USB bus. Please refer to the second manual CH340DS2 for more information on the USB convert to printer interface.

In infrared mode, a USB infrared adapter can be created by adding an infrared transceiver to the CH340, allowing for SIR infrared communication.

CH340 Features

  • Full speed USB 2.0

  • Emulates standard serial interface, can be used to upgrade older equipment to USB

  • Baud rate from 50bps to 2Mbps

  • 5V and 3.3V power

  • SSOP-20 package

  • CH340 Applications

  • USB to UART conversion

  • Upgrading old devices to USB

  • Programming microcontrollers

 

Specifications

WCH(Jiangsu Qin Heng) CH340G technical specifications, attributes, parameters and parts with similar specifications to WCH(Jiangsu Qin Heng) CH340G.

CH340G Tech Specifications

WCH(Jiangsu Qin Heng) CH340G technical specifications, attributes, parameters and parts with similar specifications to WCH(Jiangsu Qin Heng) CH340G.

Product Attribute Attribute Value
Package / CaseSOP-16_150mil
PackagingTube-packed
TypeTransceiver
Product Attribute Attribute Value
Supply Voltage3.3V 5V
Data Rate2Mbps
ProtocolUSB 2.0
Product Attribute Attribute Value
RoHS StatusRoHS Compliant
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CH340 Applications

  • USB to UART conversion

  • Upgrading old devices to USB

  • Programming microcontrollers

CH340 Equivalents

FT232, CH340G

How to use CH340

The CH340 is a simple USB to serial IC that converts USB signals to UART, which is used to interface with older appliances and microcontrollers.

Because the ATMega329P utilized in these boards does not have built-in USB functionality, it communicates with a computer via a UART interface, which is translated to USB using the CH340.

CH340 Circuit

The data connections on the UART side are provided by connecting the TX and RX serial pins to pins PD0 and PD1 of the microcontroller, respectively. Another noteworthy feature is that the DTR pin is connected to the reset pin via a capacitor, which resets the microcontroller whenever a serial connection or USB connector is plugged in. On the USB side, the D+ and D- pins are linked to the USB connector's respective pins. A USB clock is also provided by a 12MHz crystal (together with its load capacitors). The CH340 can be used as a simple USB to serial interface with this simple circuit setup.

 

CH340 vs. CP2102

The biggest difference is the USB interface. The real one uses a CP2102 USB to UART Bridge. The copy uses a CH340G chip. The CH340G is notoriously unstable and liable to die at a moment’s notice.

 

CH340 Dimension

CH340 Manufacturer

Nanjing Qinheng Microelectronics Co., Ltd., formed in 2004, is a business that specializes in RF and high-speed digital-analog mixed Integrated Circuit design, as well as MCU core research. Ethernet, Bluetooth wireless network, USB, and PCI interface chips, as well as MCU + microcontroller integrated with the above interfaces, are all available from us. ADC/PGA and other analog detection, MCU smart control and driving algorithm, HID human-computer interaction, Ethernet/Bluetooth-LE and other network communications, UART/USB/USB PD/PCIE/CAN/SerDes and other interface communications, data security, IoT protocol, and cloud service are all part of our technology.

 

Frequently Asked Questions

What is CH340?
To put it simply, Ch340 is a USB bus convert chip. It allows the USB to be converted to serial interface, serial signals to USB, etc. You can even think of Ch340 as a trader of some sort!
What is CH340 used for?
CH340 can be used to upgrade the former serial interface peripheral equipment or add an extra serial interface for the computer via the USB bus. Supply RS232, RS485, RS422, and another interface via adding a level change device.
What is Arduino Nano CH340?
The key studio Nano CH340 is a small, complete, and breadboard-friendly board based on the ATmega328P-AU. Compared with ARDUINO NANO, the USB-to-serial port chip used in key studio Nano is CH340G, so that the using method is the same except for the driver installation file.
FAQ
What is CH340?
To put it simply, Ch340 is a USB bus convert chip. It allows the USB to be converted to serial interface, serial signals to USB, etc. You can even think of Ch340 as a trader of some sort!
What is CH340 used for?
CH340 can be used to upgrade the former serial interface peripheral equipment or add an extra serial interface for the computer via the USB bus. Supply RS232, RS485, RS422, and another interface via adding a level change device.
What is Arduino Nano CH340?
The key studio Nano CH340 is a small, complete, and breadboard-friendly board based on the ATmega328P-AU. Compared with ARDUINO NANO, the USB-to-serial port chip used in key studio Nano is CH340G, so that the using method is the same except for the driver installation file.

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