Download - Current FED Tester Status
04/22/23 James Leaver
Current FED Tester Status
04/22/23 James Leaver
Software Status• FED Tester software is in a
fairly refined state
• Universal Toolbox class enables full calibration, configuration and initialisation of system with a single function call
• Toolbox configures and provides access to:
– FED Testers
– FED
– FED Kit
– Frame data generator
– FED event wrapper which transparently enables readout though Slink or VME
• Forms the core of several testing programs, which could easily be used at RAL
• Entire FED Tester Software package: 31,563 physical lines of code so far…
TrimDAC
Calibration FTE AOH
Calibration FED Timing
Calibration
Calibrator
Configurator
Allow User To
Make Changes Initialise Device
Descriptions
Initialiser
Toolbox
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To Devices
Provide Access
To Descriptions
Initialise
Devices
04/22/23 James Leaver
TrimDAC & AOH Calibration
• TrimDAC calibration:
– FED Tester output disabled
– FED TrimDACs calibrated (Fed9UDevice method)
– TrimDAC values increased to shift baseline below FED ADC range – ensures efficient use of ADC range when optical input from FED Testers is present
• AOH calibration:
– FED Testers output alternate digital high / digital low signals to each FED channel
– FED Tester AOH bias currents and gains are adjusted for each FED channel to optimise use of FED input ADC range
04/22/23 James Leaver
TrimDAC & AOH Calibration: Results
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FED ADC range (digital low → digital high) post TrimDAC and AOH calibration:
04/22/23 James Leaver
FED Timing Calibration
• FED Testers send tick marks to FED
• All FED coarse and fine delay settings are scanned through
• Appropriate FED delay settings for each FED channel are found, to ensure optimal data sampling points
04/22/23 James Leaver
FED Timing Calibration: Results
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Positions of calibrated sampling points on a tick mark for FE Unit 0:
04/22/23 James Leaver
FED Inter-Channel Crosstalk
• Wanted to measure the effects of crosstalk between FED channels
• Will show two sets of results here:
– ‘Worst Case’:
• 11 of 12 FE Unit channels carry a ‘noise’ signal, look at crosstalk on remaining channels
– ‘Nearest (& Next Nearest) Neighbour’:
• 1 of 12 FE Unit channels carry a ‘noise’ signal, look at crosstalk on neighbouring channels
04/22/23 James Leaver
Crosstalk: Worst Case: Setup
• Sent typical frame to FE Unit channel 5
• Sent similar frame to other FE Unit channels, but added a delay of 10 clock cycles
– (Repeated for each FE Unit)
• Used FED Testers to simultaneously phase shift all frames relative to FED sampling point, from 0 to ~25 ns in ~100 ps steps
– By capturing Scope Mode data from the FED at each phase step, can build up a high resolution image of signal seen by FED
04/22/23 James Leaver
Crosstalk: Worst Case: Results
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Simple Crosstalk Measurement (offset_frame)
********************* Gener al Set t i ngs ********************* *** Cur r ent FED set t i ngs: FED - Read Rout e = FED9U_ROUTE_SLI NK64 FED - DAQ Mode = FED9U_MODE_SCOPE FED - Scope Lengt h = 512 FED - Test Regi st er = NORMAL *** Cur r ent FTE set t i ngs: FTE - Tr i gger St at e = REPETI TI VE FTE - L1A Per i od = 39900 FTE - L1A Low Rat e Per i od = 39900 FTE - L1A Random Rat e = 164 FTE - Mi ni mum Tr i gger Spaci ng = 36 *** Cur r ent FTE FM set t i ngs: FTE FM - Cl ust er Defi ni t i on = MULTI _STRI P FTE FM - Cl ust er Wi dt hs Fi l e = FTeFr ameMaker Fi l es/ FTe_Cl uWi dt hDi st r _Si mul at i on. t xt FTE FM - Gaussi an Noi se Level = 0 ###################################################################### I ni t i al set t i ngs: *** Fr ame Number i ng: Fr ame 0 = ' Level ' f r ame Fr ame 1 = ' Pul se' f r ame Phase shi f t f r ame 0 : TRUE Phase shi f t f r ame 1 : TRUE Fr ame 1 f r ame del ay = 10 Fr ame 1 pedest al val ue = 1200 Fr ame 1 hi t val ue = 2000 Fr ame 1 hi t posi t i on = 60 Fr ame 1 hi t wi dt h = 1 Fr ame t o FE Uni t channel mappi ng: Channel : 0 1 2 3 4 5 6 7 8 9 10 11 Fr ame: 1 1 1 1 1 0 1 1 1 1 1 1 ######################################################################
FE Unit 0: A view of the overlapping frame digital headers - All channels apart from 5 see the blue input signal
04/22/23 James Leaver
Crosstalk: Worst Case: Results(2)
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Simple Crosstalk Measurement (offset_frame)
********************* Gener al Set t i ngs ********************* *** Cur r ent FED set t i ngs: FED - Read Rout e = FED9U_ROUTE_SLI NK64 FED - DAQ Mode = FED9U_MODE_SCOPE FED - Scope Lengt h = 512 FED - Test Regi st er = NORMAL *** Cur r ent FTE set t i ngs: FTE - Tr i gger St at e = REPETI TI VE FTE - L1A Per i od = 39900 FTE - L1A Low Rat e Per i od = 39900 FTE - L1A Random Rat e = 164 FTE - Mi ni mum Tr i gger Spaci ng = 36 *** Cur r ent FTE FM set t i ngs: FTE FM - Cl ust er Defi ni t i on = MULTI _STRI P FTE FM - Cl ust er Wi dt hs Fi l e = FTeFr ameMaker Fi l es/ FTe_Cl uWi dt hDi st r _Si mul at i on. t xt FTE FM - Gaussi an Noi se Level = 0 ###################################################################### I ni t i al set t i ngs: *** Fr ame Number i ng: Fr ame 0 = ' Level ' f r ame Fr ame 1 = ' Pul se' f r ame Phase shi f t f r ame 0 : TRUE Phase shi f t f r ame 1 : TRUE Fr ame 1 f r ame del ay = 10 Fr ame 1 pedest al val ue = 1200 Fr ame 1 hi t val ue = 2000 Fr ame 1 hi t posi t i on = 60 Fr ame 1 hi t wi dt h = 1 Fr ame t o FE Uni t channel mappi ng: Channel : 0 1 2 3 4 5 6 7 8 9 10 11 Fr ame: 1 1 1 1 1 0 1 1 1 1 1 1 ######################################################################
Level shift of ~4 ADC counts
when blue frame goes low (power issue?)
Level shift of ~4 ADC counts
when blue frame goes low (power issue?)
Spikes of ~10 ADC counts in amplitude
Spikes of ~10 ADC counts in amplitude
04/22/23 James Leaver
Crosstalk: Nearest Neighbour: Setup
• Send typical empty frame to all FE Unit channels apart from 5
• Send a frame to FE Unit channel 5 which has a 2-strip wide ‘pulse’ in the centre of the payload
– (Repeated for each FE Unit)
• Use FED Testers to phase shift frames sent to channel 5 (keep constant phase for other channels) – build up high resolution signal images as before
• Repeat with 3 pulse heights:
– Pulse 1: Pedestal to digital high
– Pulse 2: Pedestal to (2/3) * (digital high)
– Pulse 3: Pedestal to (1/3) * (digital high)
04/22/23 James Leaver
Crosstalk: Nearest Neighbour: Results
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• FE Unit 2: All channels apart from 5 see the blue input signal
• With maximum ‘noise’ pulse height:– Nearest neighbour crosstalk
amplitude: ~3.5 ADC counts
– Next nearest neighbour crosstalk amplitude: negligible
04/22/23 James Leaver
Crosstalk: Nearest Neighbour: Results(2)
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04/22/23 James Leaver
FED Channel Noise
• Simple noise measurement:
– Disabled FED Tester output and set appropriate FED TrimDAC / OptoRx values (constant across all channels)
– Captured a Scope Mode event for each FED channel (Scope Length = 1020)
– Found mean and standard deviation of signal at each channel:
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FTE opt i cal out put s : DI SABLEDFED DAQ Mode = FED9U_MODE_SCOPEFED Scope Lengt h = 1020FED Test Regi st er = NORMALFED Opt o Rx i nput off set = 0x5FED Opt o Rx out put off set = 0x3FED Tr i m DAQ off set = 0xa0
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FTE opt i cal out put s : DI SABLEDFED DAQ Mode = FED9U_MODE_SCOPEFED Scope Lengt h = 1020FED Test Regi st er = NORMALFED Opt o Rx i nput off set = 0x5FED Opt o Rx out put off set = 0x3FED Tr i m DAQ off set = 0xa0
04/22/23 James Leaver
FED Hit Check
• Wanted to check that the numbers / locations of hits input to the FED match the numbers / locations of hits output by the FED in Zero Suppressed Mode.
04/22/23 James Leaver
FED Hit Check: Setup• Ran with 100 kHz random triggers, FED in Zero Suppressed Mode
• Used randomly generated events with simulated CMS cluster distribution (2% Tracker occupancy)
• Set FED strip high & low thresholds to 50
• Set the hit height in our randomly generated frames to vary (almost) between pedestal and digital high
– i.e. from just below the FED strip threshold to near the top of the FED ADC range
• Generated 1024 events (FED Tester capacity), read them out through the FED, generated another 1024 events, repeated 100 times
• Compared every input hit ADC value with every output hit ADC value; expect a linear scatter graph of non-zero values if FED detects every input hit correctly
04/22/23 James Leaver
FED Hit Check: Results
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Hit Value Output by FED Vs Hit Value Input by FTE
FED Channel 0: Graph contains data from ~5 x 105 hits
04/22/23 James Leaver
FED Hit Check: Results(2)
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Close-up of linear region
04/22/23 James Leaver
FED Hit Check: Results(3)
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Extreme close-up of linear region
04/22/23 James Leaver
FED Hit Check: Results(4)
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A close-up of the region around the FED strip threshold:The FED appears to detect a small fraction of hits that occur below the strip threshold!
04/22/23 James Leaver
FED Hit Check: Results(5)
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A scatter plot of the same data shows the effect more clearly:
‘Hits’ below FED threshold
‘Hits’ below FED threshold
‘Hits’ detected when input
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‘Hits’ detected when input
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04/22/23 James Leaver
FED Hit Check: Unexpected Non-Zero ADC Values
Cluster 1
Event Data
Cluster 2
Noise
Why does the FED return non-zero ADC values for strips that do not contain valid hits?
→ Due to data packaging format:
i.e. 1 Cluster
FED Strip Threshold
1 Value Below Threshold
2 clusters separated by 1 strip:
• Transmitted as 1 cluster
• Read out noise level at the strip in-between, instead of zero
• Non-zero ADC value = ‘false hit’
OR
1 cluster with 1 strip below threshold:
• Transmitted as 1 cluster
• Read out below-threshold hit level, instead of zero
• Non-zero ADC value = ‘invalid hit’
04/22/23 James Leaver
FED Hit Check: Unexpected Non-Zero ADC Values(2)
• The non-zero ADC values transmitted due to data formatting might be intentional…
– Or perhaps the Fed9UEvent class could filter them out with a threshold cut…
• To work around the issue, the FED Hit Check was repeated using randomly generated frames containing only single strip clusters, separated by more than 1 strip
– Reduced Tracker occupancy to 1% to account for increased data volume
04/22/23 James Leaver
FED Hit Check: Single Hit Results
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All invalid ‘hits’ have vanished
All invalid ‘hits’ have vanished
Result: FED is correctly identifying all input hits
04/22/23 James Leaver
FED Hit Check: Single Hit Results(2)
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Results from all 96 FED channels:
04/22/23 James Leaver
FED Efficiency Test
• Wanted to test that FED operates correctly with:
– 100 kHz random triggers
– High Tracker occupancy
– Slink readout
– FED throttling system in place
• Also wanted to test FED efficiency (fraction of events lost vs. Tracker occupancy) predictions made by Emlyn
– However, the assumptions used in earlier predictions have changed:
• Emlyn used 2 bytes per hit (strip position, ADC value)
• Now have cluster finding (cluster position, cluster width, ADC values)
• Emlyn used back-to-back frames
– Could reproduce Emlyn’s conditions, with fixed 2 strip wide clusters and back-to-back frames…
– … But our goal is to replicate CMS, so more realistic conditions were used (FED efficiency prediction should still be reasonably accurate)
04/22/23 James Leaver
FED Efficiency: Buffering in ZS Mode
• Large buffers: 80 MB/s FE-BE link dominates
• Occupancy reaches ~9% before events are lost
Front-End @ 140 kHz (b2b frames) Back-End @ 140 kHz (b2b frames)
• Large buffers: slink dominates
• Events lost when:
– Occupancy ~1.4% at 100 MB/s
– Occupancy ~2.8% at 200 MB/s
Emlyn’s predictions:
→ → Slink data rate determines FED efficiencySlink data rate determines FED efficiency
04/22/23 James Leaver
FED Efficiency: Experimental Setup
• Random 100 kHz triggers
• FED in Zero Suppressed mode
• Readout rate through Slink limited to maximum of 200 MB/s
• Sent randomly generated frames with simulated CMS cluster distribution
• Increased simulated Tracker occupancy of generated frames and recorded fraction of events vetoed by FED
04/22/23 James Leaver
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FED Efficiency: Cluster Distribution
Mean = 2.96 strips per cluster
Average size of hit = 1.91 bytes
(Emlyn’s average hit size = 2 bytes)
Mean = 2.96 strips per cluster
Average size of hit = 1.91 bytes
(Emlyn’s average hit size = 2 bytes)
Simulated cluster distribution was generated from the plots in Figure 4 of Ian Tomalin’s CMS-IN 2005/025 Note:
Note: Would clusters of this size really exist?
04/22/23 James Leaver
FED Efficiency: Results
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L1As Vetoed Vs Tracker Occupancy (200_sim1)
********************* Gener al Set t i ngs ********************* *** Cur r ent FED set t i ngs: FED - Read Rout e = FED9U_ROUTE_SLI NK64 FED - DAQ Mode = FED9U_MODE_ZERO_SUPPRESSED FED - Scope Lengt h = 6 FED - Test Regi st er = NORMAL *** Cur r ent FTE set t i ngs: FTE - Tr i gger St at e = RANDOM FTE - L1A Per i od = 400 FTE - L1A Low Rat e Per i od = 40000 FTE - L1A Random Rat e = 164 FTE - Mi ni mum Tr i gger Spaci ng = 36 *** Cur r ent FTE FM set t i ngs: FTE FM - Cl ust er Defi ni t i on = MULTI _STRI P FTE FM - Cl ust er Wi dt hs Fi l e = FTeFr ameMaker Fi l es\ FTe_Cl uWi dt hDi st r _Si mul at i on. t xt FTE FM - Gaussi an Noi se Level = 0 ################################################################################ I ni t i al set t i ngs: Number of t r i gger s t o send per t est = 10000000 I ni t i al Tr acker occupancy per cent = 0 Tr acker occupancy st ep = 0. 05 Number of Tr acker occupancy per cent ages t o t est = 400 Maxi mum r eadout r at e ( MB/ s) = 200 ################################################################################
Events lost when occupancy exceeds ~2.8% with 200 MB/s readout rate
04/22/23 James Leaver
FED Efficiency: CRC Errors
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Numbers of Errors Vs Tracker Occupancy (200_sim1)
********************* Gener al Set t i ngs ********************* *** Cur r ent FED set t i ngs: FED - Read Rout e = FED9U_ROUTE_SLI NK64 FED - DAQ Mode = FED9U_MODE_ZERO_SUPPRESSED FED - Scope Lengt h = 6 FED - Test Regi st er = NORMAL *** Cur r ent FTE set t i ngs: FTE - Tr i gger St at e = RANDOM FTE - L1A Per i od = 400 FTE - L1A Low Rat e Per i od = 40000 FTE - L1A Random Rat e = 164 FTE - Mi ni mum Tr i gger Spaci ng = 36 *** Cur r ent FTE FM set t i ngs: FTE FM - Cl ust er Defi ni t i on = MULTI _STRI P FTE FM - Cl ust er Wi dt hs Fi l e = FTeFr ameMaker Fi l es\ FTe_Cl uWi dt hDi st r _Si mul at i on. t xt FTE FM - Gaussi an Noi se Level = 0 ################################################################################ I ni t i al set t i ngs: Number of t r i gger s t o send per t est = 10000000 I ni t i al Tr acker occupancy per cent = 0 Tr acker occupancy st ep = 0. 05 Number of Tr acker occupancy per cent ages t o t est = 400 Maxi mum r eadout r at e ( MB/ s) = 200 ################################################################################
FED Efficiency Test yields unexplained distribution of CRC errors at high Tracker occupancies…
04/22/23 James Leaver
FED Efficiency: Theoretical Vs Measured Data Rates
• Theoretical data rate from CMS Note 2002/047:
– TIB1 ‘Full’ FED (180 of 192 APVs)
– Zero Suppressed, 100 kHz triggers, Occupancy of 2.8 - 2.9%
→ Data rate = 109.5 MB/s109.5 MB/s
• Measured data rate at occupancy of 2.9% = 217.8 MB/s217.8 MB/s
• Reason for discrepancy?
– Current ‘formatting’ information (non-data) = 816 bytes / event
– CMS Note ‘formatting’ information (non-data) = 112 bytes / event
– Assume current average data padding = 32 bytes / event
– Scale by FED fill factor of 180 / 192
• ‘Corrected’ measured data rate = 139 MB/s139 MB/s
04/22/23 James Leaver
FED Efficiency: Theoretical Vs Measured Data Rates(2)
• ‘Corrected’ measured data rate = 139 MB/s139 MB/s
• Can use average cluster width of generated frames to estimate expected data rate:
→ 132 MB/s 132 MB/s (good agreement)
• Calculate average of 1.55 bytes / hit for Ian’s data:
– Implies large number of clusters with 4 or more hits
– TIB1 cluster distribution in CMS Note must be different to that used in measurement - should account for remaining discrepancy…
• Conclusion:
– A true data rate comparison would require more accurate cluster distribution data for the frame generator
– Results show some agreement with Emlyn’s prediction, but cannot demonstrate FEDs performance in final system until we have accurate cluster distribution information and the FED Zero Suppressed ‘Lite’ mode
• i.e. Current data rates are significantly higher than those expected at CMS
04/22/23 James Leaver
Summary
• FED Crosstalk:FED Crosstalk:
– Unpleasant effects when a single frame arrives at the FED out of sync with the others…
– …But crosstalk caused by ‘hit’ features is small and should only impact nearest neighbours
• FED Channel Noise:FED Channel Noise:
– Average noise is less than 1 ADC count, with no significant variation from channel to channel
• FED Hit Check:FED Hit Check:
– FED correctly identifies hits in Zero Suppressed mode (for a 2% Tracker occupancy)
• FED Efficiency:FED Efficiency:
– FED vetoes triggers at high data rates in a similar manner to that predicted by Emlyn, but Zero Suppressed ‘Lite’ mode required for genuine CMS performance characterisation
– Measured data rates show reasonable agreement with theory, but a more accurate cluster distribution is required
04/22/23 James Leaver
Unresolved FED Problems…
• FED still randomly produces a small fraction of events with CRC errors (~1 in 1-10 million events, depending upon Tracker occupancy)
– Possibly a timing issue due to transition to new FPGA tools…?
04/22/23 James Leaver
What Do We Test Now?
• Still need to investigate:
– Pedestal variations
– Pipeline addresses
– Use of TTC
– etc.
• Need to prioritise remaining tests, and check that all important areas are included…