18.01.06J. Jones (Imperial College London), Alt. GCT Mini-Meeting GCT Source Card

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Transcript of 18.01.06J. Jones (Imperial College London), Alt. GCT Mini-Meeting GCT Source Card

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18.01.06J. Jones (Imperial College London), Alt. GCT Mini-Meeting GCT Source Card Slide 2 J. Jones (Imperial College London), Alt. GCT Mini-Meeting2 18.01.06 Overview Source Card Tasks Separate e/ from jets Condense 2x68-way SCSI (RCT) 4x1.6Gbit/s optical fibre BC0 sync. checking (compare TTC with BC0 embedded in data) Autocalibrated delay to phase match data on different channels (if required) USB 2.0 interface for diagnostic/testing (borrowed from IDAQ-APVE) Swtiches data between channels to provide split information to leaf cards Extra features On-board temperature/status monitoring Read out either during gaps in data (via concentrator card)or via USB Data capture from RCT (for debugging) Internal test pattern generation (up to 1024BX) for testing leaf cards, etc Can (in theory) scale to 2 x required bandwidth (pin-compatible part) Slide 3 J. Jones (Imperial College London), Alt. GCT Mini-Meeting3 18.01.06 6/8-layer 6U VME form factor USB 2.0 (Cypress SX2) TTCrx & QPLL 2xVHDCI SCSI for RCT input 4xOptical SFP output & SerDes Linear supplies for fast components Switch-mode (TI) for logic Either: 2 x XC3S1000-4FT256 (~80) Simpler design Longer latency Or: 1 x Xilinx Spartan 3 4-8 x Xilinx Coolrunner-II CPLD More complex design Lower Latency Board Layout (Preliminary) 2 3 4 4 5 5 6 7 7 Slide 4 J. Jones (Imperial College London), Alt. GCT Mini-Meeting4 18.01.06 Functional Issues (To Be Discussed) Clock Distribution Direct from QPLL Split by dedicated clock buffer (made by TI) No PLL in splitter to minimise jitter Max skew ~500ps (OK for 80MHz) SerDes TLK2501 seems like a good choice with bandwidth margin ECL Termination Scheme Have a version done, but would like to discuss with Wisconsin first Similar to Bristol IM, with a few extra tweaks / options Use same buffers (they have wide common-mode range, +5V to -4V) Slide 5 J. Jones (Imperial College London), Alt. GCT Mini-Meeting5 18.01.06 Source Card Latency RCT->Leaf (Maximum Limit) Madison Cable (quoted from datasheet) 1.5ns/ft Assume 5ft max. length => 1.5x5 = 7.5ns delay ECL Buffers 2.5ns-6ns (4ns typical) FPGA/CPLD FPGA (XC3S1000): 5ns in IOBs, at a guess >5ns trace delay = 10ns CPLD (Coolrunner-II): 3.8ns-7.1ns total delay SerDes 38 bit-times@1.6GHz (625ps) = 23.75nsbit-times@1.6GHz PCB Tracking Assume 10-inch@300ps/inch = 3ns Optical Fibre (20m) 50ns-75ns? Estimated Total: 7.5+6+(3.8 10)+23.75+3 = 44.05ns-50.25ns ~ 2BX + 2-3BX Slide 6 J. Jones (Imperial College London), Alt. GCT Mini-Meeting6 18.01.06 Source Card Skew (Maximum Limit) Madison Cable (quoted from datasheet) 0.025ns/ft maximum Assume 5ft max. length => 0.025x5 = 0.175ns skew ECL Buffers 1ns max. (part-part) FPGA/CPLD Negligible skew (can be controlled) SerDes N/A PCB Tracking Can (will) be controlled Estimated Total: 0.175+1 = 1.75ns J. Jones (Imperial College London), Alt. GCT Mini-Meeting10 18.01.06 Build Plan & Price (Guess) Schematic J. Jones (IC) Layout S. Greenwood (IC) Power supplies currently be laid out Manufacture (awaiting quote from Cemgraft) Have checked, theyre not very busy a.t.m. Cemgraft (assembly/parts) ExceptionPCB (PCB manufacture) Good experience with complex high-speed boards in the past 18 RCT crates x 6 cables / 2 => 54 cards Should be ~60,000 for 60 required (with spares) Slide 11 J. Jones (Imperial College London), Alt. GCT Mini-Meeting11 18.01.06 Schedule Schematic (1-2 months) Currently 60-70% complete Aim to finalise by end of February Layout (2 months) End of February, possibly mid-March Parts (2 months, may be 3 if delayed) Critical parts ordered by end of January (avoiding specialised ones) Aim to get prototype parts by submission date Firmware (2 months) J. Jones & A. Rose USB software & firmware already written Major component left is clocking / calibration firmware for data path March/April is contingency (leaf card is probably not available until the end of April?)