BBC BASIC Programmers' Reference

This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong.

=====Sending a serial break=====

//by Richard Russell, July 2007//\\ \\  Occasionally you may wish to send a **break** condition on a serial port output line. For example this may be needed to 'wake up' a remote device such as a modem. You can easily do that using the following code:\\ \\ 
<code bb4w>
        SYS "SetCommBreak", @hfile%(com1%)
        WAIT 50
        SYS "ClearCommBreak", @hfile%(com1%)
</code>
Here **com1%** is the value returned from [[http://www.bbcbasic.co.uk/bbcwin/manual/bbcwinf.html#openport|OPENUP]] when the serial port was opened. In this example the **break** condition is maintained for about 0.5 seconds (50 centiseconds).\\ \\  For completeness here is a self-contained program which opens the port, sends the break, and then closes the port:\\ \\ 
<code bb4w>
        com1% = OPENUP("COM1:9600,n,8,1")
        IF com1% = 0 ERROR 100, "Couldn't open serial port COM1"

        SYS "SetCommBreak", @hfile%(com1%)
        WAIT 50
        SYS "ClearCommBreak", @hfile%(com1%)

        CLOSE #com1%
</code>