read whole response and check crc

diff --git a/lib/RFID/Serial/3M810.pm b/lib/RFID/Serial/3M810.pm
index 9a01e1b..41fd380 100644 (file)
--- a/lib/RFID/Serial/3M810.pm
+++ b/lib/RFID/Serial/3M810.pm
@@ -67,23 +67,22 @@ sub cmd {
                $r_len = $port->read(3);
        }
 
-       # FIXME sometimes, reader returns left-over junk
-       if ( ! ord(substr($r_len,0,1)) && 0xD0 ) {
-               warn "INVALID reponse ",as_hex($r_len);
-               my $c;
-               while ( $c ne "\xD6" ) {
-                       $c = $port->read(1) || return;
-                       warn "# c ",as_hex($c);
-               }
-               $r_len = $c . $port->read(2);
-               warn "FIXED ",as_hex($r_len);
-       }
-
        wait_device;
 
        my $len = ord( substr($r_len,2,1) );
        $data = $port->read( $len );
-       warn "<< ", as_hex($r_len,$data)," $len\n";
+
+       while ( length($data) < $len ) {
+               warn "# short read ", length($data), " < $len\n";
+               wait_device;
+               $data .= $port->read( $len - length($data) );
+       }
+
+       warn "<< ", as_hex($r_len,$data),
+               ' | ',
+               substr($data,-2,2) eq checksum(substr($r_len,1).substr($data,0,-2)) ? 'OK' : 'ERROR',
+               " $len bytes\n";
+
 
        $coderef->( $data ) if $coderef;