Zone Sensor Controller
Eight of the PIC I/O lines are used as inputs. A pair of photo-transistors
at a zone boundary are connected to two lines and make one zone
sensor. This will give four zone sensors per card. The controller
responds to the following commands.
Command Function
--------- ---------------------------------
0100 0000 Poll(respond with status byte)
On a poll command it returns one of the following two status bytes.
Response Function
--------- ------------------------------------
0010 0000 Entered zone to the left
0010 0001 Entered zone to the right
0010 0010 Left zone on left
0010 0011 Left zone on right
0010 0100 Presence on zone on left detected
0010 0101 Presence on zone on right detected
0010 0110 No status change since last poll
Updated on 2 Nov 95. Feedback to