[ukvac] [Tech] Dual game roms
As in a previous post, i'm considering burning a set of Wild Ride roms to go
on a Do Run Run board.
I can think of a way to piggy back the new roms onto the old ones, lift the
+5v pins on all the roms and wire them to some kind of switch device, but
that would mean a major spaghetti junction style wiring job to go round all
the roms and color proms.
I'm pretty sure i've had discussions about this in the past that i didn't
quite grasp, where there were much more elegant solutions involved - one
that was mentioned was double size roms where the address lines were
switched(?), or something like that.
I can vaguely remember about inverting the high bit on the address bus via a
dip switch so the CPU never actually knows that where it's reading it's rom
data from is not actually where it thinks it's getting it from, but how you
would physically do this in terms of wires and chips is another matter.
Anyone care to elaberate on a possible (and preferably neat) way of doing
this - on or off-list?
If i'm talking out of my arse then feel free to tell me to shut up :O)
Cheers,
Guddler.
---------------------------------------------------
Martin White
Coming real soon...
http://www.guddler.btinternet.co.uk
Yet another arcade site(!) with info on games owned, repair logs (as and
when), projects and more.
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
As in a previous post, i'm considering burning a set of Wild Ride roms to go
on a Do Run Run board.
I can think of a way to piggy back the new roms onto the old ones, lift the
+5v pins on all the roms and wire them to some kind of switch device, but
that would mean a major spaghetti junction style wiring job to go round all
the roms and color proms.
I'm pretty sure i've had discussions about this in the past that i didn't
quite grasp, where there were much more elegant solutions involved - one
that was mentioned was double size roms where the address lines were
switched(?), or something like that.
I can vaguely remember about inverting the high bit on the address bus via a
dip switch so the CPU never actually knows that where it's reading it's rom
data from is not actually where it thinks it's getting it from, but how you
would physically do this in terms of wires and chips is another matter.
Anyone care to elaberate on a possible (and preferably neat) way of doing
this - on or off-list?
If i'm talking out of my arse then feel free to tell me to shut up :O)
Cheers,
Guddler.
---------------------------------------------------
Martin White
Coming real soon...
http://www.guddler.btinternet.co.uk
Yet another arcade site(!) with info on games owned, repair logs (as and
when), projects and more.
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/