Hi Folks,
I've been pinging on people individually about different ways to use a
digital sound board on standard Cinematronics hardware (goal is put all game
code and sounds on a couple or really big EPROMs)
Anyway, rather than continually forward messages around, I created a mailing
list, similar to the one I maintain for folks interested in hacking Williams
hardware to be switchable between 8 different games ( for
those who may be interested). This list has been very successful in helping
discuss ideas, coordinate projects and tasks, all while maintaining an
extremely high signal to noise ratio.
Currently mail to gets forwarded to:
(let me know about additions and deletions, since I maintain the list by hand)
Anyway, my current tact is to explore the possibility of interfacing a
Williams sound board with the Cinematronics hardware (when all you have is a
hammer... ;-) Since most of the sound signals are digital enable/disable
signals, this should be straight forward (note I did not say easy ;-),
assuming we can figure out how to program the sounds for the Wlms sound board.
Even if we can't we can always just digitize the entire waveform and use
write a small 6800 program to play them on the sound board (thanks to Sean
Riddle for the idea) EPROM space is a lot cheaper today than it was in 1982,
so this is a reasonable option.
Unfortunately, there are some signals that are not straight enable/disable
that need to be dealt with.
Here are the simple signals for the two games I have (and have docs for):
Star Castle
-----------
J4-12 Loud explosion
J4-13 Soft explosion
J4-14 Laser sound
Rip Off
-------
J4-14 Torpedo
J4-15 Laser
J4-16 Explosion
All the other sounds are encoded into a serial stream that is clocked into an
8 line shift register, then clocked into a latch (obviously a way to try and
get more signals to the sound board) Each game uses one line for serial data,
one clock line to the shift register, and one line for a load pulse to the
latch.
Here are the gooey details:
Rip Off
-------
J4-11 Serial data
J4-12 Shift clock
J4-13 Latch load pulse
Latch signals:
Background frequency and pitch control (3 select lines)
Background enable
Beep
Motor 1
Star Castle
-----------
J4-11 Latch load pulse
J4-15 Shift clock
J4-16 Serial data
Latch signals:
Background frequency and pitch control (3 select lines)
Background enable
Thrust enable
Star enable
Shield enable
Fireball enable
Not too bad to deal with. A couple 4066s in between the cpu board and the
new sound board should be able to move the input control signals so that they
can share the same serial->parallel circuit, then only enable/disable signals
can be sent to the new sound board, right? Tricky part is the multiple
encoding lines for the frequency/pitch of the background sounds, but a big
enough EPROM could solve that problem.
Things are starting to get complex, but still manageable. Of course, the
scheme only accomadates 2 games so far, so I'm fearful it will collapse under
its own weight.
Questions for you folks:
How do the sound signals to the Armor Attack and Solar Quest sound boards look like?
How about Space Wars, Warrior, and Tail Gunner? (or any other games you may
be interested in?)
I want to get a handle on the scope of the problem before trying to devise a
real general purpose solution.
Thanks
--- Ray Ghanbari Mayo Foundation
