'sonar example program.
dist    var     word            'sonar distance var.
redled  con     10
speaker con     9
                                'sonar pins.
init    con     4               'change these for different pins.
binh    con     6
echo    con     5


output init                     'sonar init.
output binh                     'sonar binh.
output speaker                  'speaker output.
output redled                   'red led.
input echo                      'echo pin.

                                'setup for sonar.
low init                        'init pin.
low binh                        'binh pin.

low speaker                     'turn off speaker.
low redled                      'turn on red led.

test
        gosub sonar             'get sonar reading.
        debug dec ? dist        'print it to serial port.
        pause 1000              'pause 1 sec.
goto test                       'loop back.



sonar
        high init               'hit transducer.
        pause 1                 'pause for ringing.
        high binh               'raise inhibit.

        rctime echo,0,dist      'wait for echo.

        dist=dist/73+9          'dist has number of inches.
                                'offset for ringing is 9 inches.
                                'sound travels 1 inch in about 73us.
                                'rctime increments in 2us increments.

        pause 40                'give it a rest.
        low init                'reset sonar stuff.
        low binh
return                          'done.