Re: Cinematronics multigame?

In message "Cinematronics multigame?", vectorlist@spies.com writes:

>
> 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.

Sounds ok, but may be prone to race conditions where unexpected code is
executed. On my board I use the JPP instruction to latch the pre-loaded
bank selection register and force a "soft" reset by loading the program
counter with zero.

> This also leaves the game-select signals available for sound hardware.

Yes, it also leaves them available for per/game dip switch settings.

> 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?

Not only is it feasible, it's already working!

> 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.

Cool, I'm using boxes and circles at the moment, characters would be nice!
I can test your ROMs, just send them down, god knows I've burned enough of 'em
for this particular platform!

Later-
Mark
Received on Mon Mar 16 18:48:25 1998