57 lines
1.2 KiB
Perl
57 lines
1.2 KiB
Perl
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# A little input demo
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use Comedi qw( :Functions :Constants :Ioctls ) ;
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use Comedi::Trigger;
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use Comedi::Lib;
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use constant AI_DEV => 0;
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use constant AI_SUB => 0;
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use constant AO_DEV => 0;
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use constant AO_SUB => 1;
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use constant N_SAMPLES => 100;
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$fn = '/dev/comedi0';
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# create a channel list
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#
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@ch = ( CR_PACK(0, 0, AREF_GROUND),
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CR_PACK(1, 0, AREF_GROUND) );
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$d = comedi_open($fn) || die "Can't open '$fn': " . comedi_error();
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$fd = comedi_fileno($d);
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open(COMDEV, "<&$fd") || die "Can't get filehandle from fd $fd: $!";
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$freq = $opt_f || 1000;
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comedi_loglevel(4);
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# convert the requested frequency into a timer value
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#
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($ret = comedi_get_timer($d, AI_SUB, $freq, $ticks, $actual_freq)) == 0 ||
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die "Can't get timer: " . comedi_strerror($ret);
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$buf = pack('S*', 100..(100+N_SAMPLES-1));
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# create a trigger object
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#
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$it = new Comedi::Trigger(
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mode => 2,
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chanlist => \@ch,
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n => 20,
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data => \$buf,
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major => $ticks,
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minor => 20);
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die "Analog input trigger error ($ret): " . comedi_strerror(comedi_errno())
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if (($ret = comedi_trigger($d, $it)) < 0);
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($ret = sysread(COMDEV, $buf, 2*N_SAMPLES)) || die "Read error ($ret): $!";
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foreach (unpack('s*', $buf)) {
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printf("%d\n", $_);
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}
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