The AHRSComms alarm will be raised whenever the OP board
is not able to communicate with the AHRS board.
The navigation software on the OP board could use this
alarm to trigger its best attempt at an emergency landing.
git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@1002 ebee16cc-31ac-478f-84a7-5cbb03baadba