[Elphel-support] Older camera and still images - NC323-2

[support-list]

Hi Mitch,

KAI-11002 maybe is the largest CCD sensor with "electronic shutter" (and that was the reason to use those sensors for the original NC323 applications), but it may be only sub-optimal for the long exposure time astronomical applications.

Changing exposure limits should be possible, but at room temperature I do not think you can get above 30-60 seconds.
All the CCD timing is controlled by a sort of a program for the FPGA sequencer and it is run-time modifiable.

Here is the script that runs in the camera to setup analog parameters and loads the program:
http://elphel.cvs.sourceforge.net/viewvc/elphel/camera323/apps/ccd/ccd_pgseq?view=markup
Exposure is implemented by 2 nested loops (due to limit on the counter width) around the line 223

And here are the 2 Verilog files that describe the sequencer:
http://elphel.cvs.sourceforge.net/viewvc/elphel/camera323/fpga/x324/ccd_seq.v?view=markup
http://elphel.cvs.sourceforge.net/viewvc/elphel/camera323/fpga/x324/seq_cpu.v?view=markup

Web interface writes directly to the program memory location (127?) that defines the loop duration, and you probably need to modify the other location(126?) , the one that defines the other of the two nested loops (each counter seems to be 12 bit, so 4095 is the max)

This is a backend program used by the web interface (current 353 cameras just use php for that):

http://elphel.cvs.sourceforge.net/viewvc/elphel/camera323/apps/ccd/ccd.c?revision=1.10&view=markup

Andrey






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