Serial Programming

References

• Serial Programming HOWTO
• Serial Programming Guide for POSIX Operating System
• Serial Port Programming in Windows and Linux

How-To

Flush Serial Buffers

Use constant TCSAFLUSH for function tcsetattr (see [1] and [2]):

Constants for tcsetattr

Constant	Description
TCSANOW	Make changes now without waiting for data to complete
TCSADRAIN	Wait until everything has been transmitted
TCSAFLUSH	Flush input and output buffers and make the change

This can be done even on a serial port that is already configured:

  struct termios  options;
  tcgetattr(fd, &options);                   // Get current configuration of this port
  cfsetispeed(&options, B115200);            // Configure some port options (e.g. baud rate...)
  ...
  tcsetattr(fd, TCSANOW, &options);          // Apply the new settings immediately 
  ...                                        // Read / Write to the port...                       
  tcsetattr(fd, TCSAFLUSH, &options);        // Flush IO buffer

Tools

Minicom

Minicom (wikipedia) is a text-based modem control and terminal emulation program for Linux.

It can be used to debug / test serial connections, but unfortunately it is only ascii based and does not allow to send / receive easily data in hexadecimal format (except via sending / receiving files).

Cutecom

Cutecom is a handy and easy graphic tool to test/debug embedded devices controlled via serial link. This tool allows sending / receiving data in hexadecimal format.