Package sers offers serial port access for the Go programming language. It is a stated goal of this project to allow for configuration of non-traditional bit rates as the may be useful in a wide range of embedded projects.
Primarily the library provides an implementation of the SerialPort interface
for the supported platforms. For every serial port, you get the functionality
of an io.ReadWriteCloser as well as methods to set and query various
parameters. Secondarily it helps you communicate with the users of your
programs through the use of mode strings that represent the data than can be
written and read with {Get,Set}Mode.
The SetMode() and GetMode() methods allow setting and retrieving key
parameters such as baud rate, number of data bits, number of stop bits and the
used parity scheme. As far as the underlying platforms support it, SetMode
allows you to set arbitrary, non-traditional baud rate. The generation of
break conditions is supported through the SetBreak() method. The behavior
of the Read() method can be fine tuned with the SetReadParams() method.
The library offers the concept of mode strings like 9600,7e1 or
57600,8n1,rtscts. These can be parsed by ParseModestring into an internal
representation that can be set through SetModeStruct. The mode string is quite
flexible and allows omission of certain parts. Mode strings are easily read and
written by humans. This makes the user interface of programs that use serial
ports easier to create and use: programs do not need to provide a plethora
of command line switches, but can accept one string and delegate handling
to sers.
Due to backwards compatibility there is a difference in data representation
between SetMode and GetMode.
sers has been successfully used on Mac OS X, Linux and Windows.
The following known restrictions apply.
cgois needed to compilesers- Using non-traditional baud rates may not work. This depends on whether the
system headers have correct definitions for
struct termios2. Traditional baud rates use traditional termios baud rate setting methods via defines such asB1200etc. The author is successfully using non-traditional baud rates on Linux, though.
- Calling
GetModebefore having calledSetModewill result in an error. cgois needed to compilesers
- Only
NO_HANDSHAKEis supported.
Compilation for Linux and OS X involved use of cgo and thus a C compiler.
This makes cross compilation harder for every user of sers.
If all necessary definitions for serial port handling can be expressed in Go, it is conceivable to make a pure-Go version for both these operation systems.
Adding deadline methods, SetDeadline as well as Set{Read,Write}Deadline.
On termios platforms this relatively easy as we can let the runtime netpoller do the heavy lifting. On Windows I do not yet understand the most promising path to implementation.
Building on deadlines, {Local,Remote}Addr methods would enable a SerialPort
to implement net.Conn. This makes it easy to plug a SerialPort into various
network protocol implementations that build on byte streams.
With a working deadline implementation, the wart of SetReadParams could be
dropped or, at least, relegated to platform specific support. {Get,Set}Mode
can be made to both take a Mode struct. Representation of parity, stop bit
and handshake settings will be move to their own type to prevent mixups.
These changes would mean a new major version as they imply modifications that are not backwards compatible.
- add
GetMode()toSerialPort - add modestrings,
ParseModestring - add
Modestruct - add a more detailed
README.md
- termios platofrms: make
Close()unblock readers
- use our own definition of
struct termios2as the headers on a number of linux distributions are wrong. - add
verification/setbaudrate
sers appears in the primordial soup.