USB to TTL - CH340

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Operating system
| Windows Linux Operating system

USB to TTL - CH340

Introduction

在某宝买了一个 USB 转 TTL 模块，芯片型号是 CH340，芯片厂家是南京沁恒微电子股份有限公司。 产品介绍，驱动程序，技术手册和原理图页面位于USB转串口芯片:CH340。

USB to Serial Port Chips

USB 转串口芯片

Interface conversion expert

接口转换专家

Linux

进入 Linux 系统，将这个 USB 转 TTL 模块插入 USB A 口后自动识别。

dmesg

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$ dmesg -w
[  160.990615] usb 2-6: new full-speed USB device number 4 using xhci_hcd
[  161.139926] usb 2-6: New USB device found, idVendor=1a86, idProduct=7523, bcdDevice= 2.64
[  161.139932] usb 2-6: New USB device strings: Mfr=0, Product=2, SerialNumber=0
[  161.139934] usb 2-6: Product: USB Serial
[  161.165466] usbcore: registered new interface driver usbserial_generic
[  161.165513] usbserial: USB Serial support registered for generic
[  161.167670] usbcore: registered new interface driver ch341
[  161.167684] usbserial: USB Serial support registered for ch341-uart
[  161.167703] ch341 2-6:1.0: ch341-uart converter detected
[  161.168611] usb 2-6: ch341-uart converter now attached to ttyUSB0

lsusb

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$ lsusb
Bus 001 Device 002: ID 8087:8000 Intel Corp.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 002 Device 004: ID 1a86:7523 QinHeng Electronics HL-340 USB-Serial adapter
Bus 002 Device 003: ID 0c45:64d2 Microdia Integrated Webcam
Bus 002 Device 002: ID 1d57:0008 Xenta 2.4G Wireless Optical Mouse
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

udev rules

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udev /dev/ttyCH340

KERNEL=="ttyUSB*",\
    ATTRS{idVendor}=="1a86",\
    ATTRS{idProduct}=="7523",\
    GROUP="dialout",\
    MODE="0660",\
    RUN+="/bin/ln -sf %k /dev/ttyCH340"

terminal emulation program

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$ sudo screen /dev/ttyUSB0 115200

$ sudo busybox microcom -t 5000 -s 115200 -X /dev/ttyUSB0

$ sudo tio -b 115200 -t /dev/ttyUSB0

$ sudo picocom -b 115200 /dev/ttyUSB0

$ sudo minicom -b 115200 -8 -D /dev/ttyUSB0

pySerial

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$ sudo apt-get install -y python3-serial

$ sudo python3 -m serial.tools.list_ports
/dev/ttyUSB0
1 ports found

$ sudo python3
Python 3.8.5 (default, Jul 28 2020, 12:59:40)
[GCC 9.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import serial
>>>
>>> ser = serial.Serial('/dev/ttyUSB0', 115200)
>>> ser.timeout = 3
>>> ser.write(b'xyz123abc')
9
>>> ser.read(8)
b'xyz123ab'
>>> ser.read(8)
b'c'
>>>
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import serial
from serial.tools import list_ports

ports = list_ports.comports()
for port in ports:
    print(port)

ser = serial.Serial('/dev/ttyUSB0', 115200)
ser.timeout = 3
ser.write(b'xyz123abc')
ser.read(8)

Windows

驱动程序

在USB转串口芯片:CH340页面，厂家提供了 WHQL 驱动下载，支持主流 Windows 系统。

进入 Windows 系统，将这个 USB 转 TTL 模块插入 USB A 口，安装厂家提供的驱动程序。然后在设备管理器中的**端口(COM 和 LPT)**设备分类下，可以看到设备 **USB-SERIAL CH340 (COM11)**。

查看这个设备的属性，可以发现驱动程序是由 Microsoft Windows Hardware Compatibility Publisher 签名，提供商是 wch.cn，驱动程序日期是 2019/1/30，版本是 3.5.2019.1，驱动程序文件是 C:\Windows\System32\Drivers\CH341S64.SYS。

设备信息

在设备的详细信息页面中，可以看到如下在 USB-IF 注册的属性：

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QinHeng Electronics HL-340 USB-Serial adapter
USB-SERIAL CH340
USB\VID_1A86&PID_7523\5&3B489C26&0&6
USB\VID_1A86&PID_7523&REV_0264
USB\VID_1A86&PID_7523

pySerial

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PS C:\> python -m pip install pyserial
PS C:\> python -m serial.tools.list_ports
COM11
1 ports found

PS C:\> python -m serial.tools.list_ports -v
COM11
    desc: USB-SERIAL CH340 (COM11)
    hwid: USB VID:PID=1A86:7523 SER=5 LOCATION=1-6
1 ports found

PS C:\> python -m serial.tools.miniterm -h
PS C:\> python -m serial.tools.miniterm COM11 115200
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PS C:\> python
Python 3.8.6 (tags/v3.8.6:db45529, Sep 23 2020, 15:52:53) [MSC v.1927 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import serial
>>> from serial.tools import list_ports
>>> ports = list_ports.comports()
>>> for port in ports:
...     print(port)
...
COM11 - USB-SERIAL CH340 (COM11)
>>> with serial.Serial('COM11', 19200, timeout=1) as ser:
...     ser.write(b'hello')
...     ser.read(5)
...
5
b'hello'
>>>
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import serial
from serial.tools import list_ports

ports = list_ports.comports()
for port in ports:
    print(port)

with serial.Serial('COM11', 19200, timeout=1) as ser:
    ser.write(b'hello')
    ser.read(5)