15may03

List of questions for the Princeton/NIST folk

-What are the parameters you can control through the interface
(detector bias voltages, squid bias currents, predictor/corrector
parameters, parameters controlling number of samples to avg/integrate,
etc)?  How do you write these parameters (what string do you send to
the device...)

-What are the data you read back? how are they packaged and how often
do they come (must some be asked for; do some come with a
[specifiable?]  period; ...)

  -subquestion: Are there "housekeeping/diagnostic" type data that
  also come back or do you only get the detector readout?

-What of the above data comes from where? (some is through the DFB;
some may be through what we think is a plain vanilla serial line; etc)
ditto for the commands. A block diagram could be helpful here. How do
you read these data, at a level more detailed than "with the DFB"?
some may require queries; some may generate interrupts when they have
data ready; etc

-What sorts of things will we routinely have to do to calibrate or set
parameters for observations and how do we do them? (eg: set detector
voltage biases; set squid operating point; etc) How do we know when we
have to do this? that is how, often might we expect to do it, and if
we fail to do it as often as needed, what is the behavior?

-Are there diagnostic procedures you can (or must) run to check on the
electronics themselves and how is this done?  Is it likely we'll want
to reload the FPGA program (eg as a reset, or after a power failure or
glitch) and how would this be done?

-We are thinking of associating timestamps with the data in the
computer which reads out the DFB and other electronics. Is that the
right place to associate timestamps? (it's not, say, possible to do it
in the electronics themselves?)

-Can you check parameters through the interface once you've set them,
or is it a one-way (write and forget) interface? the answers may be
different for different parameters...

-What drivers do we need, and what OS's are supported? Are there any
other known hardware supports, eg, chipsets that are known to cause
problems?

-Any documentation is great

-A "dataprocessing" type question: are the data we get back "DC
coupled" in the sense that we actually get total power information?
many bolometer arrays are AC coupled (eg bolocam) and you don't get
that.


RANDOM NOTES

-Our OS doesn't support dual processors