FRITZ: a Universal Fastbus - VME Interface

Paper: 155
Session: B (poster)
Presenter: Honscheid, Klaus, Ohio State University, Columbus
Keywords: data acquisition systems, special architectures

FRITZ: a Universal Fastbus - VME Interface

K. Honscheid, C. Gwon, J. Lorenc, R. Wanke, A. Wolf
Ohio State University
174 W 18th Avenue
Columbus, Ohio 43210}

E. Lipeles, A. Shapiro, A. Weinstein, F. Würthwein
California Institute of Technology

A. Bean, D. Coppage, C. Darling, B. Forrest, T. Noor
University of Kansas

C. Strohman
Cornell University

V. Fadeyev, J. Staeck, I Volobouev
Southern Methodist University

CLEO Collaboration

The front-end electronics for several detector components of the new CLEO III
experiment will be implemented in the Fastbus standard.
Fastbus is far less popular than VME and consequently
the market for Fastbus crate controllers is small. None of the existing modules
provides sufficient performance to read-out the CLEO components.
In such a situation it is typically decided to start a new
design hoping it will not be obsolete and out-performed by the time it is finally done.
Our simpler and more satisfying solution is to make Fastbus look like VME:
FRITZ - A Fastbus Read-Out Interface with data Translation and Zero - suppression.

FRITZ consists of a standard size
Fastbus printed circuit board containing not only the Fastbus interface logic an
d ECL drivers but also a complete VME interface including a 2-slot VME backplane.
A regular VME CPU module plugged into one of the VME slots acts as
Fastbus controller.
The advantages of this approach over conventional solutions include:

Easy upgrades. As soon as a higher performance CPU module becomes available for
VME it can be used as a Fastbus controller as well.

Only one type of CPU module is needed for both VME and Fastbus crates.

A single real-time operating system and
development package (compiler, debugger...).

The same interface to the Event-Builder can be used for VME and Fastbus crates.

The same trigger interface can be used for VME and Fastbus crates.

Read-out and monitoring software is more or less identical.

Besides the basic Fastbus Controller functionality FRITZ contains a list driven
sequencer which in combination with a VME master interface copies data from the
Fastbus modules directly into the memory of the VME CPU board.
As an additional feature, memory look-up tables are included in the data path to
perform pedestal suppression and channel tagging. Optionally, header words can be
removed from the data stream.
The poster describes the architecture of the FRITZ Fastbus-VME interface.
Details of the programmed I/O, DMA, VME master/slave and data processing
submodules are discussed. Results of performance measurements are presented.