2 The CDF Experiment at Fermilab Contents - Harvard University ...

Section 2: DAQ for the Silicon Vertex Detector 23
passes them on to the FIBs its crate, and also collects the errors from the FIBs and
passes them on back to the SRC. On the SRC end, all logic that deals with four FIB
Fanouts is isolated into the SRC Transition Module, so, as far as the SRC is concerned,
there is only one FIB Fanout.
Error logging: the production SRC collects the error signals from VRB Fanouts and
FIB Fanouts, counts them and logs them.
Error handling: as the controller of the SVX DAQ system, the SRC is in charge of
how the system must respond to errors, both fatal and non-fatal, following the so-called
\Halt-Recover-Run" sequence. During the commissioning of the DAQ and the SVX II
detector, most errors will be fatal and we will investigate them individually. But once
the data taking commences, non-fatal errors will be logged, and fatal errors will be
handled in `auto-recover' mode. Here the interaction between the SRC and the Trigger
Supervisor is crucial, and it depends on whether the error is caused by the SVX system
or not, since in the former case it must take corrective action.
The necessary modications to the SRC schematics were mostly made by Felt and postdoc
Petar Maksimovic in the spring of 1998, along with the design of the SRC Transition
Module. The SRC and the SRC Transition Module printed circuit boards have been laid
out by Felt. The rst production SRC printed circuit boards were delivered in September
1998. One SRC was stued at Harvard and tested, block by block, by Felt, Maksimovic,
and graduate student Stephen Bailey, who began spending a signicant portion of his time
on the hardware side of the project. The majority of the SRC logic is implemented with
Xilinx Field Programmable Gate Arrays (FPGAs) which allows changes and new features
to be added even after the nal hardware has been assembled.
The communication between SRC and Trigger Supervisor (TS) was partially tested in
November. The rst production SRC was brought to Fermilab in November { the rst
production board in the SVX DAQ system { and the testing with the nal prototypes of
other SVX boards (FIB Fanout, FIB, VRB Fanout and VRB) began in earnest. After minor
tuning, in early December we were able to read out the SVXIII chip using the SVX DAQ
driven by the new SRC.
After that, other eight SRCs were submitted for assembly, while the SRC transition
modules were stued at Harvard. Several pairs of SRCs and their transition modules were
delivered to Fermilab in January 1999. The pilot (\pre-production") versions of VRBs and