[Gb-ccb] suggested changes to ccb library

[John Ford]

Brian Mason writes:

  < Big Snip > 

 >  c) possibly, we would like to use the "scan control bit" which is
 >  in the device interface, to control scans. We currently have
 >  proposed a somewhat awkward mechanism in which the manager secretly
 >  starts a scan just before a real scan (outlined in draft form in
 >  the use cases Melinda and I wrote some time ago). Currently i believe this
 >  bit is not accessible via the server, ie, the server interface hides
 >  this bit and manipulates it itself (possibly for very good reasons:
 >  we don't know, and would like to discuss it). Don't go off and think
 >  about this for hours, as Melinda and I still need to look into this
 >  some more with the documents you've provided to see if we think we
 >  are on to anything here.

Is there a scheme for time-tagging the data?  It seems like using the
1 PPS or equal hardware signal is needed to get it right.  The
spectrometers use the 1 PPS for a "go" signal, in that the software
arms the hardware before the one PPS, and then the 1 PPS triggers the
hardware to start the integration.  If extreme (20 millisecond-level
or better) timing is needed, then hardware augmentation of NTP timed,
RPC delivered go commands is needed.

FWIW.  I haven't been keeping up with the requirements...

John