--- 3m-810.pl	2008/09/28 14:06:59	3
+++ 3m-810.pl	2008/09/28 15:59:38	4
@@ -7,6 +7,8 @@
 use Data::Dump qw/dump/;
 use Carp qw/confess/;
 
+my $debug = 0;
+
 my $response = {
 	'd500090400110a0500027250'				=> 'version?',
 	'd60007fe00000500c97b'					=> 'no tag in range',
@@ -75,19 +77,22 @@
 #$port->stty_inpck(1);
 #$port->stty_istrip(1);
 
-cmd( 'D5 00  05  04   00   11                 8C66', 'hw version?',
-     'D5 00  09  04   00   11   0A 05 00 02   7250', 'hw 10.5.0.2', sub {
+# initial hand-shake with device
+
+cmd( 'D5 00  05   04 00 11                 8C66', 'hw version?',
+     'D5 00  09   04 00 11   0A 05 00 02   7250', 'hw 10.5.0.2', sub {
 	my ( $len, $payload, $checksum ) = @_;
 	assert( 0, 3 );
 	print "hardware version ", join('.', unpack('CCCC', substr($payload,3,4))), "\n";
 });
 
-cmd( 'D6 00  0C  13   04   01 00  02 00  03 00  04 00   AAF2','stats?' );
-#     D6 00  0C  13   00   02 01 01 03 02 02 03  00   E778
+cmd( 'D6 00  0C   13  04  01 00  02 00  03 00  04 00   AAF2','stats?',
+     'D6 00  0C   13  00  02 01 01 03 02 02 03  00     E778','FIXME: unimplemented', sub { assert( 0 ) } );
 
-cmd( 'D6 00  05  FE     00  05  FA40', "XXX scan $_",
-     'D6 00  07  FE  00 00  05  00  C97B -- no tag' ) foreach ( 1 .. 10 );
+# start scanning for tags
 
+cmd( 'D6 00  05  FE     00  05      FA40', "XXX scan $_",
+     'D6 00  07  FE  00 00  05  00  C97B', 'no tag' ) foreach ( 1 .. 10 );
 #     D6 00  0F  FE  00 00  05  01  E00401003123AA26  941A	 # seen
 
 cmd( 'D6 00  0D  02      E00401003123AA26   00   03     1CC4', 'read offset: 0 blocks: 3' );
@@ -155,7 +160,7 @@
 		$data .= $b;
 	}
 	$desc ||= '?';
-	warn "#< ", as_hex($data), "\t$desc\n";
+	warn "#< ", as_hex($data), "\t$desc\n" if $debug;
 	return $data;
 }
 
@@ -164,6 +169,8 @@
 sub assert {
 	my ( $from, $to ) = @_;
 
+	$to = length( $assert->{expect} ) if ! defined $to;
+
 	my $p = substr( $assert->{payload}, $from, $to );
 	my $e = substr( $assert->{expect},  $from, $to );
 	warn "EXPECTED ",as_hex($e), " GOT ", as_hex($p), " [$from-$to] in ",dump( $assert ), "\n" if $e ne $p;