#!/usr/bin/perl
# Jesper's MiniDDS for Linux
$serial="/dev/ttyS0";	# serial port minidds is connected to
$crystal=14318180;	# Crystal oscillator that's being used.  Note this requires a new firmware in the AVR to change because it affects serial port rate.
$resolution=$crystal/9/16777216;	# Constant used often in program...
$debug=0;		# debug mode.
$delay=0.01;
$script=$0;
$script=~s/^.*\///;

use Getopt::Std;
use Device::SerialPort;

getopts("hf:t:l:wd");

if ($opt_h) {
print "Usage: $script [-h] [-f frequency] [-t type] [-l serialline]\n";
exit 1;
}

if ($opt_d) {
$debug=1;
}

if ($opt_l) {
	$serial = $opt_l;
}

$port = Device::SerialPort->new($serial) or die "Can't open serial port: $!\n";
$port->baudrate(9600) or die "cannot set baud rate on $serial";
$port->parity("none");
$port->databits(8);
$port->stopbits(1);
$port->handshake("none");

$port->user_msg(ON);

$port->write_settings;
$port->lookclear;
print "writing spaces\n" if $debug;
($out)=$port->write("  ");
print "sent $out chars\n" if $debug;

print "reading a char\n" if $debug;

sub getachar {
my $gotchar="";
until ($gotchar ne "") {
$gotchar=$port->lookfor; # poll for data
die "no data received\n" unless (defined $gotchar);
select(undef, undef, undef, $delay);
}
return $gotchar;
}

$saw=&getachar; $l=length $saw;
print "saw '$saw' - $l characters ...\n" if $debug;
$saw=~s/^F//;
$acc=unpack "N", $saw; $freq=$acc*$resolution;
print "Current Accumulator is $acc for $freq Hz\n";
if ($opt_t =~ m/^[0-7]$/) {
print "changing waveform type\n";
($out)=$port->write($opt_t);
print "sent $out bytes\n" if $debug;
select(undef, undef, undef, $delay);
} else {
print "invalid waveform type (0-7)\n" if $opt_t;
}
if ($opt_f) {
die "Error: can't use 0 as frequency" if ($opt_f == 0);
$acc=int ($opt_f/$resolution);
$got=$acc*$resolution;
$error=int ( 100000*(($opt_f-$got)/$opt_f))/1000;
$saw=pack "N",$acc;
print "sending new accumulator value '$saw' " if $debug;
print "-> Setting want=$opt_f got=$got error=$error%\n";
($out)=$port->write("s$saw");
print "sent $out bytes\n" if $debug;
if ($opt_f > ($crystal/9/16)) {
print "WARNING: frequency exceeds resolution, WAVEFORM WILL BE JITTERY\n"
} elsif ($opt_f > ($crystal/9/64)) {
print "warning: frequency exceeds resolution, waveform is very degraded\n"
} elsif ($opt_f > ($crystal/9/256)) {
print "warning: frequency exceeds resolution, waveform will have missing samples\n"
}
}

if ($opt_w) {
### custom for my minidds
print "writing into eeprom\n";
($out)=$port->write("w");
}