The trigger request lines (TREQ) are the trigger (FastOr) signals from the tracker layers to the TEM level 1 trigger (L1T). Each layer has two TREQs, one from the left side and one from the right side. These two TREQs are connected to two different readout cables. The L1T logic OR's the two signals. This is important because if one cable is not connected it's input to the OR might be high and therefore the output of the OR is always high. The OR connect to a one-shot that generates that will be used in the trigger logic. If the OR is always high the one-shot never fires and doesn't contributes to the trigger.
The lowest and top most layer of the prototype tower (btem) are y-layer, i.e.: they measure the y coordinate (the strips run parralel to x). In the documention Tracker Tower Stack Addressing the lowest and top most layers where assumed to be x-layers.
One word to the usage of left and right. We use left and right only for the kapton cable.
Looking at a side of the btem, the cable to your left is the left cable(L) and the cable to your
right is the right cable(R). :)
Early versions used left and right for the controller chips, but is not used any more.
The two controller chips on a hybrid are controller R0 and R1. Each cable is connected
to a specific type of a controller chip.
| cable | cable type | controller type | read during beamtest |
|---|---|---|---|
| 0 | L | R0 | yes |
| 1 | R | R1 | no |
| 2 | L | R1 | no |
| 3 | R | R0 | yes |
| 4 | L | R1 | no |
| 5 | R | R0 | yes |
| 6 | L | R0 | yes |
| 7 | R | R1 | no |
The following table shows the naming convention for the tracker layers and the assosiated treq signals of the TEM VME board.
| Y-layers |
|
X-layers |
|