Draft: Self trigger studies and implementation

Use the new self trigger capabilities of FW 3.2.1 (and up).

Self trigger on the KCU can be enabled with

kcu.write_node("READOUT_BOARD_0.TRIG_ENABLE", 1)

Trigger masks can be applied through the TRIG_ENABLE_MASK_{i} register (to be studied).

The ETROC has to be set into dual port mode, with not merging trigger data -> separate data and trigger links

etroc.wr_reg("singlePort", 0)
etroc.wr_reg("mergeTriggerData", 0)
etroc.wr_reg("triggerGranularity", 4)  # should give us 8 bits of trigger data

This only works on module board v0b because the trigger data is expected to be on the second lpGBT.

What needs to be done:

• find the proper L1A delay so that we get the actual hit that triggered the event
• get an estimate for the noise trigger rate, and understand how the thresholds impact this rate