$newvalue = join(',', (unpack('H*', $value) =~ /(..)/g))

##</code><code>##

($newvalue = $value) =~ s/(.)/sprintf('%02x,', ord($1))/ge;
chop($newvalue);

##</code><code>##

$newvalue = join(',', map { unpack('H*', $_) } split(//, $value));