Hit Buffer (HB) board
There is one HB for each phi wedge, 12 total
HIT is generic name: SVX hits + XTRP tracks
Receives hits and stores in Hit List Memory (HLM)
- Hit List Memory is 64K words, 21 bits each.
- allocate fixed number of words (2 or 4 or 8) to each SuperStrip in each Layer (e.g. 4 SVX hits, 1 XTRP track). Excess data is lost.
- Hit List Memory = Data Base keyed by SuperStrip
- Maps hits ? SuperStrips via VME-loaded LUT.
- LUT also defines the number of words in HLM for each SS
Receives roads and sends out hits belonging to each road
- Loops on layers with internal counter
- Maps layer,road ? SuperStrip via VME-loaded LUT
Stores input & output in Spy Buffers