XFEL C+C HARDWARE : REQUIREMENTS 1) To receive, process and store Timing Signals from TR ( Timing Receiver ) in same crate : - 5 MHz Bunch CLOCK - Bunch train TRIGGER - Event Number = TRAIN ID - BUNCH PATTERN or Bunch PATTERN ID 2) To receive BUNCH VETO from Veto Hardware 3) To receive STATUS / ERROR ( and possibly Busy ?? ) from each FEE 4) To distribute to each FEE three fast lines : MHz un-interrupted clock, phase-locked to 5 MHz Bunch Clock - START pulse, followed by TRAIN ID, followed by PATTERN ID, followed by STOP signal - BUNCH VETO signal 5) To process any BUSY information from crate controller to stop the following START pulse 6) To generate all Timing Signals in Stand-Alone mode without TR 7) To synchronise to other light sources Timing Systems, i.e. to accept external CLOCK and possibly TRIGGER at different frequencies 8) To provide diagnostic and visual indication of CLOCK, TRIGGER, etc. performance and presence / absence of any FEE

t1 T1 T2 T1+T2 5 MHz clock in TRIGGER in 100 MHz clock out TRIGGER out VETO out INPUTS AND OUTPUTS – TIMING RELATIONSHIP D2 D1 VETO in

XFEL C+C HARDWARE : MORE INFORMATION / QUESTIONS -1- 1) TRIGGER Telegram from TR : - same line / different lines for TRIGGER, Train ID, Bunch Pattern ?? - Bunch Pattern or Pattern ID ? ( Pattern ID look-up table on C+C ?? ) 2) FEE feedback line : Status only ( e.g.. Normally floating high, pulled low by FEE when powered ), or will contain information ( e.g.. go high when busy or error ) ?? 3) External clock input at other test sites : - 20 MHz range ?? - Always use internal 100 MHz clock or PLL to different clock ?? 4) Bunch Veto signal – how fast / latency ?? 5) Calibration Pattern ?? ( pre-loaded into a memory on C+C ?? ) 6) Veto Disable Pattern ?? 7) 100 MHz clock output : - max. jitter ?? - programmable delay / step size ?? 8) Output Clock / Start/Stop pulses phase relationship : - only adjustable on C+C Master, i.e. same for all FEEs ?? - same cable length for all FEEs ?? - or individual delay adjustments on each C+C FanOut => more complex FanOuts ??

XFEL C+C HARDWARE : MORE INFORMATION / QUESTIONS -2- 9) Connection between C+C Master and FanOuts : - on custom backplane all signals / FEE feedbacks only ?? - use single or double FanOut layer ?? 10) C+C FanOut cards : - separate power on backplane => not TCA-intelligent cards ?? - separate dumb FanOut cards and crate ?? - on / near detector => fewer cables ?? 11) LVDS connectors : - RJ45 – bulky, 4-pairs only, but can use 2x LEDs - Double-stack RJ45 – availability / height ?? - HDMI - size / more signal pairs / more grounds/shielding ?? - Double stack HDMI - size ?? - mini-HDMI ?? 12) Is there any C&C System interface to MPS ( Machine Protection System ) ??