Re: Mark IV Electronics Design

[Chris Albertson <chris@topdog.pas1.logicon.com>]

Tom Droege wrote:
> 
> Dan, Chris,
> 
> Neither of you seem to be addressing the problem.  How do you interface a data
> source that *must* put out a large bolck of data at a fixed rate?  It seems
> to me
> there needs to be a buffer somewhere.

You are right.  I had forgotten that you wanted to read out
the CCD at a fixed pixel per second rate.  I can see why you
need that.  The Mk III driver ties to do the same thing.  It
reads pixels at a fixed 8Khz.

You do need a buffer.  The question is size.  If you were
going to mass produce Mk IV camera then a few dollars
saved in the buffer RAM would pay off.  I was a bit surprized
that you did not find a FIFO chip.  I would expect that
you could buy them but have never looked.  I do know
that they make external printer buffers but a chip must be
cheaper.  

I agree that buffer design is a minor detail.  I had thought
that you could use a standard pin out cable at no extra cost
or effort.  But if you are sending synchronus data then I
doubt you do have the requied signals, so pinout does not
matter.

--Chris Albertson

  chris@topdog.logicon.com                Voice:  818-351-0089  X127
  Logicon RDA, Pasadena California          Fax:  818-351-0699