Sliding Windows to Global Chip Data Transfer in the TAB

updated: 13-Jul-04

Data Format

Notes

1. Cluster Data Format
   Only SW chips (1-8) send out cluster information. Cluster types and positions are given in the format: Type(eta,phi) [for example EM(4,1)], where:
   • Type = EM, Jet, Tau
   • eta = relative eta index of cluster sent out from this chip (0-8 - note only 2-5 are output)
   • phi = relative phi index of cluster sent out from this chip (0-8 - note only 2-5 are output)
   The highest threshold passed by EM, Jet and Tau clusters is encoded as in 3-bits as follows:

   3-bit Value	Meaning
   0	This cluster is not a local maximum
   1-7	This cluster is a local maximum Value = indes of highest Et threshold passed

   
   
2. Sums
   Constructed of EM+H TT Et's summed over all 40 eta bins in a phi-slice.
   • Sum(EM Et) outputs, present in the Run IIa L1Cal, but not used in any triggers have been suppressed. No use for these is foreseen in the current L1Cal trigger.
3. L2/L3 Data
   Each SW chip buffers its unique 4x4 (in eta x phi) region of EM and H input TT's on each BC. It sends the data from the appropriate BC to the Global chip on the TAB for each L1 Accept at 90 MHz. Data is multiplexed onto 2 output lines.
   • Time required for transfer:
     1(em/h) x 4(eta) x 4(phi) x 8-bits x 11ns/bit / 2-lines = 0.7 us
     (not taking into account any framing bits)