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TDCB Status report

TDCB Status report. Bruno Angelucci , Stefano Venditti. NA62 meeting, 14/12/2011. Outline. Delivery of 11 TDCBs (last meeting) Firmware improvements TDC windows: a non-problem solved First tests on rates and cross-talk Future plans. TDCBs delivery.

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TDCB Status report

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  1. TDCB Status report Bruno Angelucci, Stefano Venditti NA62 meeting, 14/12/2011

  2. Outline • Delivery of 11 TDCBs (last meeting) • Firmwareimprovements • TDC windows: a non-problemsolved • First tests on rates and cross-talk • Future plans

  3. TDCBs delivery 11 TDCBsdeliveredtoallgroupswhorequestedthem • Mountingproblems on theTDCBs: • Oneboard’s RAM mountedupside-down (back to the firm) • Glue on oneboard’s PP connector (scratchedaway) • Some componentsadded (connectors, pins, resistances) • Firmwaretestedstep-by-step (TDC-TDCB-PP exchangetokens, wordslossespatched) and installed on eachof the TDCBs • TDCB manualupdated: severalpointsmadeclearer, manymistakescorrected • VHDL/Tell1/TDCB startupsession at CERN with at leastonepersonfromeachinterestedgroup (18/10/2011)

  4. Firmwareimprovements • The first issueaddressedafter the last meeting was the long-time “recompiling” problem(unstablefirmwareafterrecompilation, loss ofwords and/or tokens). • The problemhas (probably) beentraced back to some signalsused in the TDCB logic, whose clock wasthatfrom the TDCs. Firmwarerecompilingwasalwayssuccessfulsincethesecorrectionswereintroduced • not a proof, but a strong hint! • FIRMWARE CONVERSION TO MENTOR HDL DESIGNER • TDCB firmwareconversionfromQuartus II toMentorstartedby Marco • severalblocksmadeclearer/lesscumbersome • the conversionisalmostcompleted, the “new” firmwarewillbetested in the nextweeks

  5. TDC & TDCB functioning • 1 TDCB → 4 TDCs→ 128 channels • TDCs output: leading and trailingwords (info on TDC index, channelnumber, timemeasurement at ~100 ps resolution) • Words go into a 4 word-deepderandomizer, then in a 256 word deep L1 buffer (through a round-robinof the 8 ch. group) • Eventsfrom the 4 L1 buffers are passedto the readout FIFO ld/tr. (0x4/5) TDC channel(32) 01010100010111010101100100010101 eventtime (19 bit) TDC number & board (4x4) • TDCBsgetwordsfromTDCs end deliversthemtoPPsthrough a tokenexchangemechanism (no hand-shaking) • A time-stamp (rollover ~107 s) and a word counter (#lead+#trail+time-stamp) are attachedto the bunchreceivedfromone TDC followingone trigger

  6. TDC windows The secondissueaddressedis the optimalconfigurationfor the TDC time windows (set through the TDC configurationstring) TRIGGER OFFSET (TROFF): trigger latencyforeachincoming trigger REJECT OFFSET (REJOF): rejectlatencyforeachincoming trigger MATCHING WINDOW(MAWIN): timeinterval in whichwords are taken SEARCHING WINDOW(SEWIN):timeinterval in whichwords are searched Whenrunning in trigger mode the matching windows MUST cover all the acquisitiontime (and possiblyavoidrepetitions) • timeinterval are in 25ns steps • MAWIN= N = (N+1) x 25 ns • REJOF at least 1 c.c. > TROFF • SEWIN at least 8 c.c. > MAWIN

  7. Anatomyof a non-error In orderto look forpossible data loss we set the acquisition system asfollow: • 12.8 µs cyclic pattern from pattern generator, 1 LVDS 25 nssignal/channel, 32 channelsfired; • Trigger to TELL1 sent by the pattern generatoritself at the end of the pattern, using the TRIGOUT port TDC windows settings: 32 CH. PATTERN TROFF: 0xE00 (-12.8µs) REJOF: 0xDF0 (-13,05µs) MAWIN: 0x1FF (12.775µs) SEWIN: 0x209(13.025µs) TDCB TDCB TDCB TDCB TELL-1 PG The idea wastohave a whole pattern from the PG in each TDCB trigger, making the searchforpossible data loss easier. ETHERNET LTU TRIGGER

  8. Anatomyof a non-error Aftercollecting ~1M data, about 0.1 % eventswith 1 missingleading/trailingwereobserved. POSSIBLE EXPLANATION: a “blindspace” betweentwocontiguous windows If so, increasing the TROFF and/or MAWIN windows shouldleadtoaninclusionofallwords in the packet (and severalrepetitions, curable via software) . A simple C++ programwaswrittento eliminate repetitions in contiguousevents, and several ~1M eventpacketswerecollectedvarying the windows (TROFF up to -13µs, MAWIN up to 12.825µs) However once the repetitionswereeliminated the samepercentageofmissingleading/trailingscame out Moreoverthe packets sent by the ethernet portswerenottime-ordered: thiscaused mixing betweendifferentpackets and furtherconfusion. SOLUTION: only 1 ethernet usedfor the tests (SL registermodified)

  9. Anatomyof a non-error In the end the “non-problem” wasspottedtobe due to the slightlydifferentdurationof the PG pattern wrt the TDC matchingwindow: ...... ...... 12,8+ε µs 1 “loss” Right # events 12,8 µs ONLY the numberof total wordscomparedto the numberoftriggersshouldbeconsidered, disregarding the numberofwords in the single packet. Sending the TELL1 clock to the PG wouldallowfor a pattern lastingexactlylike the TDC window, butwedidn’t manageto do this so far.

  10. First rate tests After fixing all the problems, some first rate testswereperformed: • Data collectedusinganinternal trigger for the TELL1 (ratherthansendingitfrom the PG) and sending a knownnumberofeventsfrom the PG; • At higherrates the useof 1 ethernet cableonlylimits the output MORE RATE TESTS SOON CROSS-TALK: one single channelwaspulsed at 80 KHz and masked in the acquisition. No signals in the other TDC channelsafter ~2h datataking MORE CROSS-TALK TESTS SOON

  11. Conclusions and outlook • The acquisition system isreadytoperformsystematictestsofrates and cross-talk, tobepresentedduring the next meeting • Eachgroupisinvitedtoaskforspecifictests in case ofneed • The firmwaretranspositionto HDL Designer willbefinalizedassoonaspossible

  12. Spare slide: PP & SL dataflow

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