More FED FE Testing Results

Mathew Pearson & Gareth Rogers

Plan for testing FE(status at last FED meeting)

• AIM:– Test the FE firmware.

– Test processed raw data mode.

– Test zero suppression mode.

• This involves:– Loading pedestal registers in FED, and reading back.

– Loading cluster threshold registers, and reading back.

– Loading common mode median registers and reading back.

– Re-ordering and pedestal subtraction (processed raw mode)

– Common mode median calculation and subtraction (zero suppression mode).

– Common mode median override (zero suppression mode).

– Disable strip function (zero suppression mode).

– Cluster finding (zero suppression mode).

– Complement data word (frame finding).

– FED error flags.

Plan for testing FE(current status)

• AIM:– Test the FE firmware.

– Test processed raw data mode.

– Test zero suppression mode.

• This involves:– Loading pedestal registers in FED, and reading back.

– Loading cluster threshold registers, and reading back.

– Loading common mode median registers and reading back.

– Re-ordering and pedestal subtraction (processed raw mode)

– Common mode median calculation and subtraction (zero suppression mode).

– Common mode median override (zero suppression mode).

– Disable strip function (zero suppression mode). –Partly tested. Small problem.

– Cluster finding (zero suppression mode).

– Complement data word (frame finding). –Small problem.

– FED error flags.

Cluster finding

Clustering algorithm:

1. All hits above threshold 1 (T1) are accepted, except single channel clusters which must be above threshold 2 (T2). T2>T1.

2. All clusters must be at least two strips away from every other cluster. Any clusters violating this must be joined together.

Example:

4 clusters 2 clusters

Using step 1 only Using both step 1 & 2

T2

T1

Cluster findingTesting Procedure:

• Run FED in zero suppression mode.

• Set pedestals to zero.

• Enable CM calculation and subtraction.

• Set T1 and T2, where T2>T1.

• Send various hit patterns into FED from FED tester.

• Vary T1 and T2 to see effect on clusters.

The hit pattern used for these tests:

T2

T1

T1=50 T2=60

T1=50 T2=200

T1=100 T2=110

T1=100 T2=200

T1=100 T2=250

T1=160 T2=170

T1=0 T2=250 Not expected! T2 has no effect if T1=0.

T1=255 T2=255

Setting both T1 and T2 to 255 (max possible)excludes those strips from cluster finding.(expected from documentation).

In fact, one only needs to set T2 to 255 to excludestrips from cluster finding.

Cluster finding

• Conclusions:– Cluster finding algorithm working as expected.– Setting T2=255 exclude strips from cluster finding (even if T1=0).

• Observations:– T2 has no effect if T1=0 (except when T2=255). – Inter-APV cluster finding does not exist in FED. But we can lower thresholds at

APV edge if we want to cater for this (for example, in ORCA cluster finding).

– Gareth has implemented some restrictions in the Fed9USoftware (in Fed9UVmeDevice) which prevent users making undefined choices:

• Both T1 and T2 must be non-zero, or,

• Both T1 and T2 must be zero.

• T2>T1

Disable strip function

•This function will allow us to ignore a silicon strip.•Any disabled strips will be excluded from:

•cluster finding.•common mode calculation.

Initial testing procedure:•Run FED in zero suppression mode.•Set pedestals=0, cluster thresholds=0, disable CM calculation.•Send in flat data (in effect one big cluster).•Disable strips.

Then:•Set cluster thresholds to non-zero (low<high).•Send in hit pattern. •Disable strips and see if they are excluded from clusters.(sorry, no plots of this).

Disable strips

• Results:– Can disable groups of neighbouring strips. – The disabled strips are excluded from cluster finding.– Can disable the 1st and 128th strip on an APV (with no neighbouring strips).– Unable to disable any other isolated strip (from 2nd to 127th).

• Not an urgent problem, but does need to be fixed. Disabling isolated strips is something we need to be able to do.

• Conclusions and To-Do:– Disable strip function is working only for continues groups of strips.– Not yet established if common mode calculation is affected by disabling strips.

Complement Data Word• This command complements the 10-bit data word in frame finding mode 0->1 and 1->0

(has no effect in scope mode).• This will be needed if we turn off the APV inverter.

• Conclusions:– Complement is working, but....– Problem with channel ordering: The channel actually set is not the one we intended to set!

(not sure if problem is software or firmware – only discovered yesterday).

To-Do

• Find out where channel ordering error is for complement command.

• See if disable strip excludes strips from common mode calculation.– Will need to re-test this command from scratch anyway once the problem with

single strips is fixed.

• Test the FED error bits.– Skew clocks on 1 (or a few) channels so APV frame arrives too late/early.– Send in wrong APV pipeline address.– Send in APV error bits.

• Any more testing ideas very welcome!