Introduction of asymmetric pulseblaster clock ticks were not introduced in a backwards compatible fashion and has created bugs with long experiments

labscript-suite-temp / labscript_devices

Module containing labscript suite hardware compatibility, separate from the main programs. Device compatibility is implemented with a plugin architecture, for modularity and extensibility. Each file in this module contains a labscript device class, a BLACS tab class, a BLACS worker class and a runviewer parser class for a particular device. These implement functionality for the device which the programs in question call on when they encounter each device in user labscript code, hdf5 files, or connection tables.

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Introduction of asymmetric pulseblaster clock ticks were not introduced in a backwards compatible fashion and has created bugs with long experiments #16

Closed philipstarkey closed 8 years ago

philipstarkey commented 8 years ago

Original report (archived issue) by Philip Starkey (Bitbucket: pstarkey, GitHub: pstarkey).

The introduction of asymmetric clock ticks (changeset: aa9b2721a03bcc29f809492935fac9fef57d5655) has introduced a bug with long delays. It was implemented in such a way that bypasses the check for adding a LONG_DELAY opcode.

It also defaults to a clock tick of 66ns, which is extremely fast and is likely the cause of random missed triggers we've experienced in the lab for the past year.

I think it would be good to set the default behaviour (pulse_width=None keyword argument at instantiation) to use the original 50/50 high/low clock tick behaviour (thus making the change backwards compatible)

The bug with long delays should also be fixed.

philipstarkey commented 8 years ago

Original comment by Philip Starkey (Bitbucket: pstarkey, GitHub: pstarkey).

changed state from "new" to "resolved"

Restores previous symmetric clock pulses as the default behaviour for the PulseBlaster (fixes #16)

Also fixes issues with:

long delay instructions (the number of reps must be at least 2)
calculation of when to use a long delay instruction when using assymetric clock pulses
assymetric clock pulses don't make sense if it isn't used as a pseudoclock (now raises LabscriptError)

→ \<\<cset 8de5e8fb815b859102163c2cb724ac9d927dea2c>>