🚀 go-pugleaf

     Dang! I miss all the fun! In reply to Bob and others, a short
recap of CoCoIO.....
     This idea is extremely ancient- I even displayed a
schematic, etc way way back at last Chi fest. At that time, the
16553 was coming 'real soon now'- National had data sheets and
even pricing and samples! Well, things went downhill from there.
     There ain't no such chip, at least from National- and there
may never be one. And I though vaporware was an 80's kinda thing.
There are a few options left. The easiest for me is really weird-
apparantly some other chip makers cloned the 553 from the data
sheet. They forgot to include the bugs that killed 16553, and
although it appears that a few makers discontinued their product
since the expected market never appeared, what with the parent
product never released, a few are left. Thats a guess from
prelim info, since I haven't even seen full data sheets for these
chips.
     The upside is, the decoder part is a done deal. Since these
modern UARTs are timed to an ISA buss and require tons of I/O
space, thats not a trivial thing- and there is always the option
of dropping 2 16550's into the card as an easy out. The decoder
has room for 2 more. I'm shooting for Chicago again. Starting to
look pretty vaporish myself, so this is a real conservative
timeline, and may well be beat.
     Original pricing was based on what I was quoted for the not
insignificant cost of the duart/pport chip itself, and was set at
$130. This may bounce around a bit depending on part pricing from
alternate makers. As a benchmark, a dual 550 would be $10-$20
cheaper. Extra sockets, holes, and square inches of board space
cut the savings, since that moves from a 68 pin plcc (gime
package) to dual 40 pin dips.
     We ain't dead yet!
                              rickuland@delphi.com
                                    CoNect