RE: Cinematronics multigame?

> Now I remember what I was thinking for switching games. Since a
> multigame
> will need a daughter card for ROMs, I figured a game-select latch
> could
> sit on the same card with the following things happening:
>
> 1) power-up resets it to game 0 - the menu
> 2) one address line causes a second register to load i.e. if A12 goes
> high,
> the value in A0-A3 gets loaded into this second latch.
> 3) when the person "selects" a game, the menu program stops reseting
> the
> watchdog - causeing a "soft" reset which also loads the second
> register
> into the game-select register.
>
Is A12 basically unused in all games? (I wonder since Boxing Bugs has a
big EPROM daughtercard-- but I don't know much about Cinemat hardware.)

For the Sega Multigame I just mapped a new I/O address and hang the bank
select latches off of that. Even if you don't have the ability to
memory map stuff directly, you can still use the address-line only
scheme, but it might be wise to use a GAL and have a little state
machine that handles the latch. (So something like address bus=
%101010101010 followed by %01010101xxxx results in xxxx being latched.
The odds of getting &AAA followed by &55x in "real" code seems pretty
small.)

Another thing I did on the Sega Multigame which might be useful-- I was
able to find an area of memory that was big enough for the menu system
that resided in the same place across all games (of course I only had to
get 5 games to co-operate). So, the menu system could be run, and the
banks could be switched simultaneously... That let me flip banks, and
have my next instruction jump to the cold-start entry point of the game.
(Instead of switching banks and having the menu code disappear.)

> This also leaves the game-select signals available for sound hardware.
> I don't think it'd be too hard to distinguish power-on and soft-reset
> conditions to do this, and the hardware would just be a daughter card
> plugged in the ROM sockets with an extra wire to pick up the reset
> from somewhere. Sound feasible? Zonn? Anyone?
>
Sounds feasible from what I know. (Which isn't much about Cinemat, but
I like the premise. ;-)

> BTW, I've started writing a character generator for a menu program. I
> plan
> to test it out on our emulator later this week, but I still need
> someone to
> send ROM images to for testing on the real thing. Preferably someone
> who
> can burn chips and test relatively quickly.
>
FWIW, I have a DOS (and pretty much a Windows) based vector graphics
editor running for making game graphics, fonts, whatever. Just a matter
of adding an "export" routine to format the data for a particular
hardware platform. Be happy to add a Cinemat format if you like.

I can also test your Cinemat code on real hardware now too, if you
like...

-Clay
Received on Mon Mar 16 11:16:49 1998