Second Sight SVGA Board Tech Info

[jpenne@ee.ualberta.ca (Jerry Penner)]

I would like to know if there is going to be some preliminary
information available about such technical issues as memory management
on the SS VGA board (from what I understand there is no VRAM, just
DRAM), limitations on how fast bits can be pushed around on the screen
(general case, specific cases), if this Z180 CPU was chosen for any
special reason, or just because the designer was familiar with it and
it costs little.

More specifically, has a organizational scheme been implemented that
allows developers from all over the place to cooperate with regards to
downloaded software routines on the board?  Is there firmware on the Z180
side that takes care of ugly stuff like setting video modes while
checking for illegal modes based on the current monitor?  Is this
firmware written in such a way that new routines can be added without
breaking existing (downloadable) code?  Is Z180 code in general
relocatable, so that if my program has downloaded some stuff and your
program also downloads some, they won't conflict?

I don't know anything about the Z180 (but it sounds an awful lot like
a Z80 that's somehow had a bus/instruction set upgrade), so I would
like to know why it was chosen.  TMS34010's are quite cheap now and do
memory cycles in 4 CPU cycles, which is what I have been reading is
the same operation as the Z180.  The 34010, however, can do logical
pixel operations like Add with Saturate, etc, that would take a bunch
of instructions on a general purpose CPU to emulate.  Maybe 5 MB/s is
enough video bandwidth, but not if it takes the CPU 10 cycles to
figure out what to stuff onto the screen.  Does the Z180 have an
instruction cache?

Lots of questions.  A nice reasonably complete technical summary would
be nice, since if I buy this board, I do believe I'm going to have to
program it myself for the most part.  I would really like to have a
good idea of what I'm buying before I lay down the cash.
--
Jerry Penner   jpenne@ee.ualberta.ca   or   jjp@myrias.ab.ca