...card

Actually two separate cards - a 6U A32, D32 Slave card, called XL1, that fits in a standard VME crate and a 9U card, called XL2, that acts as the SNObus master.

...0

Note that VME has no A<0> line as DS0 is used to identify the odd byte.

...valid

i.e. a valid FEC cycle.

...Space).

Note that MEMREG is inverted before being put on the SNObus backplane and called RegSpace with, naturally, the inverted meaning.

...events

Calibration or Physics.

...DAQ

i.e. a board with the FIFO read pointer not equal to the write pointer

...Mask

Note that what is read from the Data Available Register is really a masked version of the state of the individual FEC board Data Available flags - a high in a given bit of the Data Available Mask Register will inhibit (mask off) the corresponding bit from ever being read as Data Available or from being recorded by the overall or of the 18 possible sources.

...J2

the FEC to High Voltage Card PMT signal connections are made via J1/J3 bypassing the backplane.

cowen@upenn5.hep.upenn.edu
Thu Dec 28 10:28:51 EST 1995