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Hardware UART Chip

Hardware: Use with easy microcontroller arduino

  • only need to connect
module serial TX pin -> arduino serial RX pin, which is arduino D0 pin
also connect the common ground.

Hardware: Use with USB-TTL Debugger: get a USB-TTL debugger here

  • recommand CP2102, CH340 or FT232.
  • Same connect the target module TX (send) pin to USB-TTL debugger RX (receive) pin. Connect debuger USB to PC, use software SSCOM to read it.
  • Recommand software SSCOM51, please find in github.

Software: Use with SSCOM

  • Switch to english version, supported
  • Please double check baudrate, stop bits, etc. For example, HLW8032 is 4800bps, EL125 is 9600bps
  • click "AddCrLF" depends on the target

Monitor Tool


SSCOM Serial USB-TTL testing tool please find here.

The rest


Check here to see the definition of UART in wikipedia.

Type Features Compatiblity Link/Datasheet Driver Price
PL2303HX - Not compatible WIN7 x
PL2303HXD (rev. D) - Compatible WIN7 7.5-10.5
PL2303TA - Compatible WIN7-10, autoupdate 4.5-7.5
CP2102 QFN28 (5x5mm) - 6-8.5
  • OTP one time program
  • QFN24 (4x4mm)
  • cheaper than CP2102,
  • 5V compatible
  • RS-485 supported
  • GPIO
- 5-7.5
  • Baudrate ~ 2M
Compatible WIN10, online install 1.5-2.5
Holtek HT42B534
  • Baudrate ~ 3M
  • VDDIO supports 1.8~5.5V for DSP
  • integrated crystal+EEPROM to store VID, etc
  • support from XP to WIN10, android 4.0+IOS
WIN10, IOS, Linux Driver free link, Datasheet 1-2

Generate Compare

USB - UART/RS-232/RS-485/RS-422

Header text Manufacturer Interface Rate Package
PL2303HX / PL2303HXD /PL2303TA USB <> 1x UART/RS-232 Example
CP2102 /CP2104 SI USB <> 1x UART/RS-232
CP2105 SI USB <> 2x UART/RS-232
CH330N WCH USB <> 1x UART 2Mbps SOP8
CH340C / CH340E / CH340G WCH USB <> 1x UART/RS-232/RS-485
CH9340 WCH USB <> 1x UART/RS-232/RS-485
CH9342 WCH USB <> 2x UART
CH9344 WCH USB <> 1x UART/RS-232 + 3x UART
CH341A WCH USB <> 1x UART / Parallel / SPI / I2C / etc
FT232RL FTDI USB <> 1x UART/RS-232/RS-485/RS-422
FT2232RL FTDI USB <> 2x UART/RS-232/RS-485/RS-422
FT4232RL FTDI USB <> 4x UART/RS-232/RS-485/RS-422
HT42B534 Holtek USB <> 1x UART/RS-232

Parallel / Serial SPI - UART/RS-232/RS-485/RS-422

  • CH438
  • CH432 || WCH || USB <> 2x UART

Serial Voltage level


Switch RS232 UART

Linux (Raspberry PI)

  • sudo raspi-config -> 选择Interfacing Options -> Serial,关闭shell访问,打开硬件串口
  • sudo nano /boot/config.txt


ISP Serial Auto download Circuits Design

  • RTS#:信号输出,初始状态为高电平,表示芯片接收数据已经准备就绪,下载程序时会变成低电平。
  • DTR#:信号输出,初始状态为高电平,下载程序时会变成低电平(但是,是在RTS变为低电平之后才为低)。

Working method for STM32 DL

Header text Normal Beginning Start Writing Finiash Writing Normal
DTR 1 1 0 0 1
RTS 1 0 0 1 1

Auto download esp

DTR 1 1 0 0
RTS 1 0 0 1
ESP8266 RST 1 0 1 1
ESP8266 GPIO0 1 1 1 0

Pulse to auto reset ciruits DTR

Arduino Serial

Hardware Serial

  • Simply flashed a sketch who does not use the hardware serial D0 / D1
  • Do not connect external device during upload sketch
  • Connect Target TXD to arduino D1, Target RXD to arduino D0
  • Open serial monitor to read data

Pages in category "Serial"

The following 5 pages are in this category, out of 5 total.