The read-out driver for the ATLAS MDT muon precision chambers

Some 200 MDT read out drivers (MRODs) will be built to read out the 1200 MDT precision chambers of the muon spectrometer of the ATLAS experiment at the LHC. The MRODs receive event data via optical links (one per chamber, up to 8 per MROD), build event fragments at a maximum rate of 100 kHz, output these to the ATLAS data-acquisition system and take care of monitoring and error checking, handling and flagging. The design of the MROD-1 prototype (a 9U VME64 module in which this functionality is implemented using FPGAs and ADSP-21160 digital signal processors programmed in C++) is described, followed by a presentation of results of performance measurements. Then the implications for the production version (called MROD-X) and the experience with pre-production modules of the MROD-X are discussed.