The Serial Programming Guide for POSIX Operating Systems will teach you how to successfully, efficiently, and portably program the serial ports on your UNIX® workstation or PC.
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Active2 months ago
I am a little bit confused about reading and writing to a serial port. I have a USB device in Linux that uses the FTDI USB serial device converter driver. When I plug it in, it creates: /dev/ttyUSB1.
I thought itd be simple to open and read/write from it in C. I know the baud rate and parity information, but it seems like there is no standard for this?
Am I missing something, or can someone point me in the right direction?
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2 Answers
I wrote this a long time ago (from years 1985-1992, with just a few tweaks since then), and just copy and paste the bits needed into each project. Data flow diagram software free download.
The values for speed are
B115200
, B230400
, B9600
, B19200
, B38400
, B57600
, B1200
, B2400
, B4800
, etc. The values for parity are 0
(meaning no parity), PARENB|PARODD
(enable parity and use odd), PARENB
(enable parity and use even), PARENB|PARODD|CMSPAR
(mark parity), and PARENB|CMSPAR
(space parity).'Blocking' sets whether a
read()
on the port waits for the specified number of characters to arrive. Setting no blocking means that a read()
returns however many characters are available without waiting for more, up to the buffer limit.Addendum:
![Linux Linux](/uploads/1/2/4/8/124860143/863290802.png)
CMSPAR
is needed only for choosing mark and space parity, which is uncommon. For most applications, it can be omitted. My header file /usr/include/bits/termios.h
enables definition of CMSPAR
only if the preprocessor symbol __USE_MISC
is defined. That definition occurs (in features.h
) withThe introductory comments of
Gabriel Staples<features.h>
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For demo code that conforms to POSIX standard as described in Setting Terminal Modes Properlyand Serial Programming Guide for POSIX Operating Systems, the following is offered.
It's essentially derived from the other answer, but inaccurate and misleading comments have been corrected.
It's essentially derived from the other answer, but inaccurate and misleading comments have been corrected.
To make the program treat the received data as ASCII codes, compile the program with the symbol DISPLAY_STRING, e.g.
If the received data is ASCII text (rather than binary data) and you want to read it as lines terminated by the newline character, then see this answer for a sample program.
Linux Serial Port Programming C Example
sawdustsawdustLinux Serial Port Programming Example For Kids
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Linux Serial Port Programming Example
protected by user405725 Jan 24 '13 at 20:53
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