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The XPM may be instructed to require a transition to obey deadtime by including bit 7 (OR 1<<7) when writing to the "MsgHeader" PV.  Ordinarily, just the TransitionId is written to this PV.

Event Codes

The XPM may be configured to insert event codes 272-287 into the timing stream.  A current example for doing this is done by executing:

(ps-4.5.24) bash-4.2$ python psdaq/psdaq/seq/seqprogram.py -h
usage: seqprogram.py [-h] [--engine ENGINE] seq pv

sequence pva programming

positional arguments:
  seq              sequence script
  pv               sequence engine pv; e.g. NEH:DAQ:XPM:0

optional arguments:
  -h, --help       show this help message and exit
  --engine ENGINE  sequence engine

(ps-4.5.24) bash-4.2$ python psdaq/psdaq/seq/seqprogram.py psdaq/psdaq/seq/33k_35k.py DAQ:NEH:XPM:6

The event codes generation by an XPM may be queried via a status PV.

(ps-4.5.24) bash-4.2$ pvget DAQ:NEH:XPM:6:SEQCODES

DAQ:NEH:XPM:6:SEQCODES 2023-01-19 10:35:20.971    

EventCode  Description  Rate

      272 "33kHz base" 33164
      273 "35kHz base" 35715
      274                  0
      275                  0
      276                  0
      277                  0
      278                  0
      279                  0
      280                  0
      281                  0
      282                  0
      283                  0
      284                  0
      285                  0
      286                  0
      287                  0

Opal

NOTE: when setting up an opal, the LCLS2 timing comes in on lane 1 (counting from zero) on the second QSFP, as described here:  https://github.com/slaclab/cameralink-gateway.

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