Re: A little more information

[<aah@nofs.navy.mil>]

The important point is that the average datarate is 400KB/s,
within the range of standard EPP/ECP port protocols (though
outside the range of the standard parallel port).  If you really
want to get rid of the memory card, I see several directions
you could head:
  (1) figure out the race condition and repair the current card.
      This is probably the first thing to try; all other solutions
      involve considerable hardware/software.
  (2) replace the ISA card with a PCI version.  This still has
      the long cable problem.  While Tom made our cablelength
      work, it is still a construction detail that should be
      avoided.  (Though I'd love to see someone design such
      a board, as there are other groups that could use a basic
      parallel port interface onto the PCI bus.)
  (3) Drop all cards and go directly into an ECP/EPP parallel port
      DB25 interface.  Probably fairly simple from the hardware
      point of view, though a FIFO would almost definitely be needed.
      Some software development.  Still long cable.
  (4) Put an ethernet interface on a local interface (like the Stamp board)
      and do all communication over that.  Fugitsu makes such chips,
      fairly easy to work with at the 10BaseT level.  However, major
      hardware and software on the Mark IV end.
  (5) Put an embedded controller near the Mark IV, use something like
      the parallel port (I'd think of a standard 8bit I/O port on
      the controller rather than a IBM PC-style printer port), then figure
      out some method of shipping the data back to the host computer.
      Again, ethernet is the most likely, though I don't know of any
      cheap controller card with on-board ethernet.  This is probably
      the most practical path, and easiest to farm out to some list member
      who is interested in low-level programming.  The advantage here is
      that most embedded controller boards come with built-in libraries
      of functions, especially if ethernet is included, so the software
      effort decreases.  Note that a standard ISA/PCI bus computer could
      be used, but the 8bit I/O is easier done with a standalone card IMHO.
Tom loses control of some aspects of the project unless path 1 or 2 is selected.
Whatever approach is used, I highly, highly recommend that all systems are
upgraded to the same solution as soon as is practical after the first such
system is shown to work.
Arne