1. Hyperterminal
2. Linux Serial Port Program

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.

Linux system generally call serial ports /dev/ttySxxx instead. To summarize, when programming for the serial interface of a Unix system it is highly advisable to provide complete configuration for the device name. May 04, 2015  In this tutorial we will see how to use the serial port on Raspberry Pi.We will use the serial port available on Raspberry with a RS232/TTL 3-5,5V adapter and a USB-serial adapter.By default the Raspberry Pi’s serial port is configured to be used for console input/output.

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?

jwwgnychis

Hyperterminal

gnychis

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.

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:

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) with

Supported OS: Windows 10, Windows 8/8.1, Windows 7, Windows Vista. The utility has been repeatedly tested and has shown excellent results. Hp deskjet 710c driver windows 7. This tool will install you the latest drivers for all devices on your computer. This utility contains the only official version for HP DeskJet 710C Driver for Windows XP/7/Vista/8/8.1/10 32-bit and 64-bit versions.

The introductory comments of <features.h> says: Hp 650 laptop drivers windows 7 64 bit.

Gabriel Stapleswallykwallyk

Linux Serial Port Program

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.

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.

sawdustsawdust

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In this tutorial we will see how to use the serial port on Raspberry Pi. We will use the serial port available on Raspberry with a RS232/TTL 3-5,5V adapter and a USB-serial adapter. By default the Raspberry Pi’s serial port is configured to be used for console input/output. This can help to fix problems during boot, or to log in to the Pi if the video and network are not available.

To be able to use the serial port to connect and talk to other devices (e.g. a modem a printer. ), the serial port console login needs to be disabled.

Here we use Raspberry Pi 2, and we connect a RS232/TTL 3-5,5V adapter to pins 4 (5V), 6 (GND) ,8 (TX),10 (RX) of Raspberry, obviously connect tx with rx and vice versa.

To search for available serial ports we use the command

The output is something like this

Last line indicates that the console is enabled on the serial port ttyAMA0, so we disable it

Run the configuration command and follow the instructions below

Reboot and try with

output now is

Now we can use the serial ttyAMA0. We connect an adapter usb / serial, then we will try to establish a communication between the two serial ports; obviously in a practical application to every serial we could connect a device, for example a modem, a printer a RFID reader etc.

After connecting the second serial port we launch the command to find the name that Raspberry gives him

The output is something like this

Ok, now we create two files, one who writes something on the ttyAMA0 port and the other that reads on the ttyUSB0 port.

serial_write.py

serial_read.py

If we run both files, serial_read.py will read what serial_write.py writes

This is just a small example but it can serve as a starting point to send a print to an old printer or read data from a router or a gps.

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