Page 1 of 7
Serial Basic Hookup Guide
Introduction
The Serial Basic is an easy to use USB to Serial adapter based on the
CH340G IC from WCH. It works with 5V and 3.3V systems and should auto
install on most operating systems without the need for additional drivers. It’s
a great lower cost option to the extremely popular FTDI Basic.
SparkFun Serial Basic Breakout - CH340G
DEV-1405 0
The Serial Basic uses the CH340G IC to quickly and easily convert serial
signals to USB. It works great with all of our products including the Arduino
Pro Mini, our GPS modules, cellular modules, and many other devices that
uses serial communication.
Suggested Reading
This is an easy board to get started with, but, if you are not sure how serial
works or have not used a terminal program before, you may want to
checkout the following tutorials.
Page 2 of 7
Serial Communication
Serial Terminal Basics
Asynchronous serial communication
concepts: packets, signal levels,
baud rates, UARTs and more!
This tutorial will show you how to
communicate with your serial
devices using a variety of terminal
emulator applications.
Serial Basic Overview
The pinout of the Serial Basic mimics the common
DTR/RX/TX/VCC/CTS/GND pinout found on hundreds of FTDI-to-USB
derivatives.
Pin Label
Input/Output
Description
DTR
Output
Data Terminal Ready, Active Low
RXI
Input
Serial Receive
TXO
Output
Serial Transmit
VCC
Supply Output
Power supply 3.3V or 5V
CTS
Input
Clear To Send, Active Low
GND
Supply Output
Ground (0V) supply
Alignment Markers
These GRN and BLK indicators are there to help you align the board
properly with products that use this same pinout.
The Serial Basic mates seamlessly with products that use the standard
serial connection. If you see a board with the BLK and GRN labels, then
you know it will be compatible with the Serial Basic.
Page 3 of 7
See the GRN and BLK labels on this nRF52832 Breakout?
Where did GRN and BLK come from? Way back in 2008, when we
created the Arduino Pro Mini, we needed to have a pinout to allow
serial bootloading. At the time, the best USB to TTL Serial device was
the FT232 Cable. Its unpolarized connector could be flipped either
way so we added the words GRN and BLK to the PCB to let folks
know how to line up the colored wires. The practice stuck! Now, many
boards use this standard.
The cable with colored wires
Voltage Selection Jumper
There is a jumper on the rear of the board that controls the output voltage
on the VCC pin. By default, the board outputs 3.3V and has 3.3V signals.
Changing this jumper to 5V will cause the board to output 5V on the VCC
pin with 5V signals.
Page 4 of 7
Jumper is default to 3.3V VCC and I/O
When the jumper is set to 3.3V, the board uses an onboard 3.3V regulator
capable of sourcing 600mA. If you attempt to pull more than 600mA, the
regulator will go into short-circuit shutdown where it will only output 150mA.
When the jumper is set to 5V, the board will source as much power as your
USB port will provide.
LEDs
There are two LEDs on the board connected to TX (Green) and RX
(Yellow). This is a quick and handy way to see the serial traffic.
Hardware Test
To connect the board to a computer, you will need a standard A to micro-B
USB cable. Plug the micro-B USB cable into a USB port on your computer
and the other end into the Serial Basic. Your computer should automatically
install the necessary drivers and create a COM port on your computer. If
you are prompted for drivers, please see the Installing Drivers section.
The quickest and easiest way to make sure everything is working is to do a
TX/RX loop-back. To do this, insert a jumper wire between TX and RX.
Anything that is transmitted from the TX pin will be echoed back to the RX
pin.
Page 5 of 7
Open your favorite terminal program. Select the COM port that the Serial
Basic is assigned to, and connect. When you type a character, you should
see each character you type echoed back in the terminal.
Success!
Which COM Port Do I Need?
Most programs will show you a description of the USB device that created
the port. Look for the port associated with CH340.
If you’re using the Arduino IDE, figuring out which COM port is the one you
want is more difficult. Here’s the quick way to figure it out: attach the Serial
Basic to your computer, and check which COM ports are listed. In the
image below, we have two ports. Now close the Tool menu by clicking on
the main Arduino IDE window.
Which COM port should I select?
Page 6 of 7
Unplug the Serial Basic, and re-open the Tools->Ports submenu. You will
see one of the serial ports is missing. That’s the one you want! Plug your
Serial Basic back in, and use that COM port.
Note: You need to close and re-open the tools menu before Arduino
will refresh the port list. If you have the tool menu open simply click on
the main window, then click back on Tools->Port.
Drivers If You Need Them
The Serial Basic has been tested on Windows 7, Windows 8.x, Windows
10, Linux Mint, and OSX Yosemite, El Capitan, and Sierra. These operating
systems have the CDC drivers pre-installed, which means you shouldn’t
need to install any extra software. However, there are a wide range of
operating systems out there, so, if you run into driver problems, you can get
drivers here.
• Windows : Driver version 3.4 (2016-09-27)
• Linux : Driver v1.4 (2015-09-12)
• Mac : Driver v1.3 (2016-09-27)
The CH340G is made by WCH. You can find the latest version of their
drivers here, but most of their pages are in Mandarin.
Resources and Going Further
Once you’ve got serial communication working, you’re ready to start playing
with serial projects. Consider connecting to a GPS module like the LS20031
(one of my favorites) and watching the serial strings roll by. Or, you can use
the Serial Basic to program and debug devices like the Arduino Pro Mini.
There are tons of devices that use serial to communicate, so go explore!
The Serial Basic programming an Arduino Pro Mini
Check out these other resources for the Serial Basic.
• Schematic
• Eagle Files
Page 7 of 7
• Hookup Guide
• Datasheet (CH340G)
• Drivers
◦ Windows
◦ Linux
◦ Mac
• GitHub
Check out these other great SparkFun tutorials.
Serial Terminal Basics
This tutorial will show you how to
communicate with your serial
devices using a variety of terminal
emulator applications.
nRF24L01+ Transceiver
Hookup Guide
A basic getting started guided to the
SparkFun Transceiver Breakout nRF24L01+
CP2102 USB to Serial
Converter Hook-Up Guide
A basic hook-up guide for the
CP2102 Breakout Board.
MIDI Tutorial
Understanding the Musical
Instrument Digital Interface.
https://learn.sparkfun.com/tutorials/serial-basic-hookup-guide?_ga=1.210804754.6480798... 2/13/2017