Speaker
Description
Summary
XFEST is a test bench designed to control the FE boards production after the
burn-in phase. Its basic idea is to inject realistic 14-bits digital patterns into
several boards in parallel at a 40 MHz clock frequency and to compare their outputs
to the ones of a "reference".
XFEST is organized in three main subsystems:
- The pattern generator used to inject the signals to the FE boards is an old
prototype of FE board working in a reverse mode (producing 25 outputs in
place of inputs), in which FPGAs have been reprogrammed for this purpose
(more details are given by another contribution to this conference).
- The data corresponding to 25 channels are then distributed to four FE boards
positioned on a XFEST motherboard. The different boards are linked through
a token ring, providing the clock and the trigger information. In order to test
a large number of FE boards during a sufficient time (10^12 different patterns
are compared per hour), we consider for the final production test the possibility
to use three motherboards.
- The two optical outputs (trigger and data streams) of the FE boards are sent
to the TCC-24 board, which is a prototype of the Trigger Concentrator Card
(TCC) developed at Laboratoire Leprince-Ringuet. This prototype used as a
comparator for this project can treat 2x12 input channels, which allows to test
up to 12 FE boards simultaneously. Any discrepancy at the bit level between one
or several boards and the reference increments the error counters.
A user web interface allows the control of the whole test bench. In a first
phase, the results of the TCC comparisons are checked with ChipScope; in a
second phase, it will be done via a VME interface.
This contribution will describe the system and report the results of the
measurements as well as mention the encountered problems.
