1. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 1 TMB and RAT Status Report Jay Hauser University of California Los Angeles

2. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 2 TMB Hardware Since April Emu@OSU Procured all FPGAs (Xilinx X2V4000) Got fixed Virtex-2 mezzanine layout from Kan I/O pads are grouped in pairs, each pair needs to use the same clock. Made 40 X2V4000 mezzanine cards 2 remaining mezzanine card problems (there were 3 simple fixes) Made 29 working sets (TMB-base, TMB-mezz, RAT) 1 base board has a bad SCSI connector 9 sets used for full-crate tests No problems seen at FAST site Procured all parts for full production (520 sets) Still waiting for some hex switches and front-panel parts (due soon) Full-crate tests done at OSU, no problems May-June test beam problem found: ALCT inputs through RAT did not work at all. RPC inputs through RAT seemed okay (minor problems).

3. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 3 RAT-to-TMB TTL Data Xmission RAT gets everything (power, gnd, control signals) from TMB Currently no connections to the common backplane TMB RAT Backplane NC

4. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 4 RAT2003A Detail To TMB GND only RPC connectors To TMB and 3.3v, 1.8v power ALCT LVDS-TTL converters Spartan 2E FPGA for RPC ALCT SCSI connectors Mechanical Only 

5. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 5 RAT-to-TMB Ground Problem May-June test beam: Only the bottom connector on backplane 110 single-ended 80 MHz TTL signals from RAT to TMB. Reference ground and current return on 6 pins. “Typical” design used for all other modules in peripheral crate: 1 GND per row of 5 pins, i.e. 25 GNDs per 125-pin connector Ground reference close to every signal Grounded to the backplane It is not a DC current problem, it is an RF problem 40 MHz noise 80 MHz signals, edges with 1-2 ns rise times.

6. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 6 Ground Issues, cont. RPC signals seemed to work at May-June t.b. They are buffered through FPGA close to connector May have slightly better RF characteristics (N.B. no CRC available). Also a problem: layout house for TMB used very thin ground and power planes ½-oz thickness of copper Usual thickness is 1-oz or 2-oz Ground plane impedances therefore higher Bench tests show very significant ground plane noise

7. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 7 TMB Ground minus RAT Ground 100 kHz ALCT 600 mV P-P 1 MHz ALCT 700 mV P-P No ALCT triggers 300 mV P-P 40 MHz noise depends on ALCT trigger rate:

8. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 8 TMB-RAT Ground Details

9. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 9 RAT-to-TMB Ground Problem Bench investigations using CRC error checking of ALCT data: Checks for any bit errors in ~800 bytes of data. Rate of errors also seen to increase with ALCT trigger rate –Errors start when ALCT readout and triggering overlap in time –Reaches ~100% before 1 MHz. Checks signal integrity through 8-bit DAQ path (out of 50 ALCT signals), i.e. many signals not checked. UC FAST site investigations using CRC: Typically 0.5-2.0% errors seen. “New and improved” short backplane –11 GNDs added, but on a different connector than TTL signals –No observed change in the rate of CRC errors.

10. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 10 Test Beam Study of TMB-RAT Interface CRC checks that every bit of ~800 bytes is transmitted correctly. May-June test beam: TMB backplane fed GND to RAT with only 6 pins. ALCT data did not successfully go through at all. Sept-Oct test beam: TMB backplane had additional connector with 11 more GND pins. ALCT errors were found only at high rates at the Sept-Oct test beam. General observation that CRC errors increase with rate agrees with bench tests.

11. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 11 Sept. 2004 Test Beam Study High-rate CRC error test: Went up to 3.4 million muons per spill before radiation alarms went off (ahem) Otherwise, ALCT-RAT- TMB worked fine 74.5 Million ALCTs 15 CRC errors

12. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 12 Conclusions on RAT-TMB Data Transmission Tests Ground noise is quite large Level of success of tests varies dramatically: Absolutely no success at May-June beam test Errors reproduced and understood with bench tests Small rate of errors observed at UC FAST site Very very small rate of errors observed at Sept beam test Variable level of success not really surprising for a noise problem Sitting on the edge of a serious problem This situation is unacceptable for long-term CMS operation, we would like to eliminate this problem entirely

13. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 13 Remedy Make the grounding for RAT like any other board in the peripheral crate: Add one ground pin on every row of RAT pins Add backplane ground connections Requires more total pins: Replace 55-pin X3 and 125-pin X18 connectors by two 110- pin Type-A connectors 40 more pins, all “C” column pins used for grounding Also more robust alignment pins (noticed RAT alignment pins already broken before Sept beam test)

14. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 14 Implications Backplane layout needs modification ~3 months, according to Alex TMB and RAT board layouts need modification Also ~3 months, according to our estimate –Includes thickening up the 1/2-oz ground and power planes and necessary changes to details of vias, thermal reliefs, etc. –Includes “cleaning up” the data pathway from RAT to TMB. Revised “loop-back” backplane used for self-testing – will add proper RAT connection for production testing (previously RAT-TMB connectors inserted by hand, subject to bent pins) More type-A connectors and backplane shrouds need to be ordered Backplane pins have long lead-time, should be ordered immediately

15. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 15 TMB/RAT Production Schedule Mezzanine card production can begin next week No problems seen with Virtex-II mezzanine card Re-layout of RAT and TMB: RAT: 2 weeks TMB: ~10 weeks Testing loop-back backplane: 1 week Quick prototype cycle in February. Production immediately after that. Testing goes quickly, more than 4 boards per working day. Deliveries of working TMB and RAT pairs: 25% by April 30 (130 of 520 boards, including 10% spares) 50% by June 30 (260 of 520 boards) 75% by August 31 (390 of 520 boards) 100% by October 31 (all 520 boards) Boards will be shipped as soon as they are tested and acceptable space (not boxes) exists for them at CERN

16. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 16 Happier Matters Active pulsing of CFEB front ends Active pulsing of test strips DAQ error checking by CRC technique New TMB counters

17. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 17 DAQ Error Checking by CRC CRC = Cyclic Redundancy Check Special “checksum” (22 bits) added to end of data block to represent pattern of 1’s and 0’s sent This checksum can be re-calculated from the 1’s and 0’s sent, then compared to the checksum received. ALCT and TMB both create CRCs for their data. TMB also checks ALCT CRC on the fly TMB adds CRC-error bit to last ALCT trailer word. TMB counts & stores in VME register the number of CRC errors from ALCT. DDU now separates CRC errors coming from ALCT, CLCT/TMB. CRC bench test: Special ALCT firmware creates dummy buffer of 400 words and responds to external trigger CRC can be checked at arbitrary rate with pulse generator

18. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 18 TMB Counters VME registers recently added for real-time counts of 23 various interesting things: ALCTs CLCTs Matched LCTs L1 Accepts ALCT readout CLCT readout MPC accepts (muon 0, muon 1) ALCT CRC errors Etc. etc. Very useful diagnostics at test beam

19. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 19 Additional Slides Follow

20. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 20 Active Pulsing of CFEB Front Ends How it’s done: All channels have capacitors with 4 levels of charge that can be preset (0,1,2,3) within Buckeye ASIC “left half-strip” puts strip charges at ….,0,0,0,2,3,1,0,0,0… “right half-strip” puts strip charges at …,0,0,0,1,3,2,0,0,0… Single VME command to DMB pulses all channels simultaneously Patterns give e.g. 6-layer CLCTs First vary 40 MHz clock phase from TMB to comparators until patterns correctly found Then patterns can be swept across entire chamber and checked Advantages: Finds optimum phase of 40 MHz clock to comparators Checks all Buckeye, comparator, and CFEB-TMB Skewclear cable channels Test takes a few minutes No gas, HV, etc. needed

21. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 21 Active Pulsing of Test Strips How it’s done: CCB provides 500ns gate to make the ALCT test strip pulses Capacitive coupling between test strips and anode wire groups gives pulses on leading and trailing edges of 500ns pulse All channels fire on leading edge Hot wire mask on ALCT board  ALCT patterns Like CFEB, vary 40 MHz receive and send phases until optimum data transmission from TMB to and from ALCT Find optimum in 2D matrix of receive/send clock phases Scan patterns across chamber to find bad AFEB/ALCT channels Advantages: Set up phases of 80 MHz clock TMB to and from ALCT with high reliability without HV, gas, or cosmic ray data Check all AFEB, ALCT, and Skewclear channels through the system What previously took days now takes minutes

22. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 22 More on TMB and RAT Power

23. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 23 TMB Ground minus RAT Ground 100 kHz ALCT 600 mV P-P 1 MHz ALCT 700 mV P-P No ALCT triggers 300 mV P-P 40 MHz noise depends on ALCT trigger rate:

24. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 24 Other Noise Measurements RAT GND versus RAT +3.3v (okay) 100 mV/division GND vs +3.3v Clock off GND vs +3.3v Clock ON GND vs +3.3v Clock ON ALCT 1 MHz

25. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 25 Other Noise Measurements TMB GND versus TMB +3.3v (okay) 100 mV/division GND vs +3.3v Clock off GND vs +3.3v Clock ON GND vs +3.3v Clock ON ALCT 1 MHz

26. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 26 Other Noise Measurements TMB “logic 1” signal as seen at RAT, 2v per division Big noise seen, as expected from GND(TMB) – GND(RAT) measurements Logic 1 Clock off Logic 1 Clock ON Logic 1 Clock ON & ALCT 1 MHz !

27. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 27 LVTTL (from +3.3v) Logic Levels Typical outputs 0.4v low, 2.4v high, transition ~1.5v Worst case output supposed to be 0.8v low, 2.0v high Measurements show violation of that

28. Endcap Muon meeting: FNAL, Oct. 29-30, 2004 J. Hauser UCLA 28 TMB, RAT Power Supply Filtering Capacitor Design TMB base board Power sources for +3.3v and +1.8v: 2x100uF, 4x4.7uF, 1x1uF, 1x0.1uF Power destinations: hundreds of 0.1 uF capacitors across board, typically several for each driver Power sources for +3.3v and +1.5v for RAT: 1x100uF, 1x4.7uF, 1x1uF, 1x0.1uF RAT board 3x4.7uF, 12x0.1uF Many 0.1 uF capacitors distributed across board, several for each driver Virtex-II mezzanine board 2x330uF, 10x47uF, ~20x0.1uF, ~40x0.022uF distributed according to Xilinx spec. Connections to TMB base board with 56 ground pins, 19 +1.5v pins, 17 +3.3v pins Comment: looks OK