Draft 0.1

			SVT to Level 3 Trigger

		       Interface Specification

			    Aug 1, 1997


This is the crudest of sketches of what the Level 3 SVT based
code would like to receive from the SVT ROMs.  The SVT based
L3 algorithm is still being formulated, and the requirements below
are not yet justified, or even demonstrated to be feasible given
expected processing power or bandwidth in the SVT ROMs.

Minimal data content to be transmitted
______________________________________


Additional data derived in the ROM
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Cluster finding for phi and Z clusters.

The Level 3 SVT algorithm works in terms of clusters rather than
digitizations.  I would like to investigate the possibility of doing
some fast cluster finding in the ROM where "fast" may mean attempts
to reduce either computation burden, e.g., doing integer rather than
floating-point computation of the cluster location, transmission
burden, e.g., by reporting cluster location to nearest strip or
inter-strip half point, or calibration burden, e.g., by ignoring
wiring corrections or small alignment corrections.  The intention is
simply to make use of computing power in the ROMs to reduce the load
on the L3 node, and to avoid unpacking the full SVT data.

Minimal data for a cluster would be position and time (time stamp
corrected for time walk, using time over threshold).  The precision
on the time shall be roughly 70ns.

Formatting
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Name			Format		Unit

phi cluster list	-		-
z cluster list		-		-


Order of packing may make a difference in speed of unpacking.