Dig Dug had 3 three Z80 CPU's why?

[vanwatson]

Why did Atari's Dig Dug have three 3 , Z80 CPU chips?

What was the reasons of having 3 , Z80's

[SavannahLion]

Why not 3 Z80s? Multi-CPU configurations were not unheard of, even back in those days.

My current project uses somewhere along the lines of five or six distinct CPU and MPUs. More if you count the onboard stuff. I lost track really.

[Malenko]

not for nothing, but why does it seem like every single one of your posts reads like "Why doesnt someone google this for me <insert topic> ?"

I guess the answer you want is that each CPU handled something else:
1 Z80 for the main CPU, 1 Z80 for Sound, and 1 Z80 for graphics. In layman's terms, one was the CPU, one was the GPU and one was the "sound card"

[SavannahLion]

I agree and I grow tired of these questions. Do we still have the ignore feature? I don't see it in the profile.

[Malenko]

http://forum.arcadecontrols.com/index.php?action=profile;area=lists;sa=ignore

you are welcome

[SavannahLion]

http://forum.arcadecontrols.com/index.php?action=profile;area=lists;sa=ignore

you are welcome

Many thanks.

[lilshawn]

the wikipedia article for the Z80 LITERALLY has an explanation why  "Bosconian, Dig Dug, Xevious, and Super Xevious" use three Z80 microprocessors.

source:
www.google.com

[pbj]

Yeah, van, stop wasting our precious, precious idle time.

[vanwatson]

This is all what wiki said about it

Frogger used two Z80 CPUs

Bosconian, Dig Dug, Xevious, and Super Xevious use three Z80 microprocessors running in parallel for the main CPU, graphics, and sound.

I didn't understand why they used 3 Z80's , because most arcade games just use 1 Z80 chip.

When you're using 2 or 3 , Z80 CPUS, what is the advantage? runs faster but what else?

[yotsuya]

not for nothing, but why does it seem like every single one of your posts reads like "Why doesnt someone google this for me <insert topic> ?"

I guess the answer you want is that each CPU handled something else:
1 Z80 for the main CPU, 1 Z80 for Sound, and 1 Z80 for graphics. In layman's terms, one was the CPU, one was the GPU and one was the "sound card"

I feel like I'm helping someone do their homework when I read van's questions.

[Malenko]

When you're using 2 or 3 , Z80 CPUS, what is the advantage? runs faster but what else?

Is this some sort of existential question?
One would venture that they used 3 Z80s because they.......... needed 3 Z80s? I know a combined 9mhz of CPU sounds like overkill but maybe it was required.

[vanwatson]

One would venture that they used 3 Z80s because they.......... needed 3 Z80s?

What made them need it? because of to many ROM chips and address lines , datalines?, control lines?

Most arcade games that use one Z80 had about 4 to 6 ROM chips and 4 RAM chips

So i'm guessing the arcade games that use 3 Z80's CPU chips had more ROM and RAM chips because of mode code and data

[SavannahLion]

One would venture that they used 3 Z80s because they.......... needed 3 Z80s?

What made them need it? because of to many ROM chips and address lines , datalines?, control lines?

Most arcade games that use one Z80 had about 4 to 6 ROM chips and 4 RAM chips

So i'm guessing the arcade games that use 3 Z80's CPU chips had more ROM and RAM chips because of mode code and data

Did you even read any of the earlier posts? The answer was already handed to you.

[yotsuya]

They should have just used a KADE and been done with it.

[vanwatson]

1 Z80 for the main CPU, 1 Z80 for Sound, and 1 Z80 for graphics. In layman's terms, one was the CPU, one was the GPU and one was the "sound card"

Yes this just makes it run faster and to use more ROM and RAM chips

But there must be other advantages or reasons

Because most arcade games had the same amount of code, rom, ram chips and sound chips and they only use one Z80

Did Frogger really need 2 Z80's chips, i have seen more complicated games that only used one Z80 chip
Did Dig Dug really need to use 3 Z80 chips, i have seen more complicated games that only used on Z80 chip

IT seems like there is reasons why they did it or  it was overkill

[pbj]

Z80s are cheap and games needed to be rushed out.  How many glitches are we going to document before everyone realizes that code quality control wasn't priority #1 back then...

[vanwatson]

Z80s are cheap and games needed to be rushed out.  How many glitches are we going to document before everyone realizes that code quality control wasn't priority #1 back then...

If they were cheap then why wasn't every arcade game using 3 Z80's , this can't be the reasons

[Malenko]

they did it to piss you off. and they were right.

[JDFan]

Reasons could be argued about for days but there is no way to know why they did what they did unless you can ask the people that did the layout -- so what good does it do to keep asking the question over and over and then argue about the answer you are given ??

Could be a simple as the designer had those parts sitting around when he built the thing and wanted to use up old inventory rather than buy new parts to use - In the end all that matters is that is what was used in the design and it worked for the purpose so was built that way 

[vanwatson]

I'm not here to fight or argue , i'm just trying to figure out way , we are brainstorming together , maybe someone might know the answer

[SavannahLion]

they did it to piss you off. and they were right.

No... they foresaw the existence of a group of enthusiasts building their own arcade cabinets using an emulator to run their code. It's an attempt to slow our builds down with asinine questions. Right now, those engineers are sitting in their retirement homes reading what is written here laughing their asses off.

Next thing you know the bot is going to ask why arcade boards don't have North or South bridges or why the clock speed isn't a multiple of 33.33 MHz. 

[yotsuya]

van-

I suggest you sign up for KLOV and ask these questions there as well. You might get more satisfactory answers.

[Malenko]

van-

I suggest you sign up for KLOV and ask these questions there as well. You might get more satisfactory answers.

While I agree he should just go over to KLOV, he'll get pretty much the same answers over there.

[yotsuya]

van-

I suggest you sign up for KLOV and ask these questions there as well. You might get more satisfactory answers.

While I agree he should just go over to KLOV, he'll get pretty much the same answers over there.

Yeah, but 90% of the dudes here are MAMErs who don't deal with original boards. I'm just thinking there might be more chipheads there.

[SavannahLion]

I'm not here to fight or argue , i'm just trying to figure out way , we are brainstorming together , maybe someone might know the answer

You're going about it wrong then. Three Z80's in Dig Dug exists. It is to be accepted. It is not ones place to ask why lest you find yourself in purgatory.

[Malenko]

totes more chip guys over there, still going to be the same answer to this question.

[SavannahLion]

totes more chip guys over there, still going to be the same answer to this question.

Which, under no circumstances,  will it understand or care. It will continue to bull forward with the questions, learning nothing... it must be a teenager...

[vanwatson]

i will start a new subject thread since this one isn't going well

[SavannahLion]

Read this before you do.
http://www.catb.org/esr/faqs/smart-questions.html

[yotsuya]

i will start a new subject thread since this one isn't going well

Please don't. A new thread isn't going to give you a different answer.

[yotsuya]

Oh, what gives....... you signed up at arcaderestoration.com to ask the same questions? 



Aren't there repair professionals there in Burbank that can assist you?

[yotsuya]

And Aussie Arcade?



OK, what gives?

[chopperthedog]

I'm shocked it took you guys this long to get annoyed. I was done at his 20th post.



good day.

[yotsuya]

I'm shocked it took you guys this long to get annoyed. I was done at his 20th post.



good day.

At first I thought it was genuine curiousity.... now it feels like someone prepping for a test... 

[SavannahLion]

Yeah I didn't even notice his crap until just recently.

[yotsuya]

What's funny is on the "Reset on Logic Boards" topic, Arcadenut, who is the site owner and most knowledgeable guy I know in this hobby, is like "Well, it depends. What game?" only to get a lot of the same "Well, in general..." from van in reply. I know Arcadenut is probably going like  right now.

[vanwatson]

just looking for some help on this stuff , not playing any game on you guys

[yotsuya]

just looking for some help on this stuff , not playing any game on you guys

I hear you. The amount of questions and their specificity just seem... odd. Most guys are like, "Hey, I got a non-working <insert game here> and I need help. 

[vanwatson]

It mostly out of arcade manuals i have read and other things I have ran across tying to fix random arcade games at friends houses.

I'm not playing any games or trying to start a fight

littleshawn and ed has been very helpful and has helped me out a lot on these things

[SavannahLion]

If that's true then your excitement needs to be tempered just a wee bit.

You seriously can't expect to have every single one of your questions answered across so many forums without receiving any sort of backlash from the community.  Your questions will have more value if you learn to research them beforehand and learn howto ask specific questions. And no, why Dig Dug has 3 Z80's isn't what I mean.

Dig Dug is done. The engineers have moved on. The answer you seek is inside the code and schematics itself, something you can find on your own. Anything else such as why they did X instead of Y is pure conjecture.

[ed12]

SavannahLion
correct
if the @ would olny ask 1 question at a time
get the answer and move on to the next,then fine
but to answer a statment with a question and or question's
is at best tireing..
van we are here to help
but best advice we can give is do some leg work..

ed

[Ken Layton]

I'm shocked it took you guys this long to get annoyed. I was done at his 20th post.



Good day.

It's like he needs to take Electronics 101 class first.

[Ken Layton]

van-

I suggest you sign up for KLOV and ask these questions there as well. You might get more satisfactory answers.

Yes, you should.

[chopperthedog]

I'm shocked it took you guys this long to get annoyed. I was done at his 20th post.



Good day.

It's like he needs to take Electronics 101 class first.

That's the thing though. His counters seem to include some knowledge, but maybe from a different type of theory and background of application.


good day.

[lilshawn]

I'm shocked it took you guys this long to get annoyed. I was done at his 20th post.



Good day.

It's like he needs to take Electronics 101 class first.

That's the thing though. His counters seem to include some knowledge, but maybe from a different type of theory and background of application.


good day.

copy paste responses from another forum?

why does knowing exactly how 2 different types of power supplies regulate the power rails and why they use this that or the other thing going to help you with your system? it doesn't. if your 5 volt is off, adjust, fix, or replace it.

having a game you are trying to fix is one issue... asking question after question after question about the idiosyncrasies of game board engineering is a little ridiculous. I get that some people need to understand how something works to figure out why something doesn't (hell i'm one of those people.) but this is a little overboard. "in general" questions aren't going to help you with your SPECIFIC case. at the time, most game makers custom made all their hardware. A likely fix for one game probably won't translate to another even though they are similar.

things iv'e gotten from your multiple multiple multiple threads.

you have a game board that doesn't boot properly (likely scrambled video image) with a monitor that doesn't quite display as it should.

reseat the socketed chips, replace the power supply, and recap the electrolytic capacitors in the monitor. this machine is damn near 30 years old. it's going to need some work. 

also in the future you can just start ONE thread (IE: "having an issues with galaga game - need major help") and post all your questions in there. that way your info isn't scattered all over hell's half acre.

good luck. You'll need it.



as for your original question about 3 CPU's...

why waste gameplay CPU cycles having to deal with video and audio when you can have a separate CPUs deal with it. if there was only 1 CPU the game would have to sacrifice game quality to be maintained centrally or be insanely slow. by separating the systems you can have great gameplay mechanic, fluid video processing, and multi voice sound all happening concurrently, processed separately and being merged together at the end for the user to experience.

[leapinlew]

The real question is why was Dig Dug, if that even is his/her name, is underground in the first place.

[vanwatson]

why waste gameplay CPU cycles having to deal with video and audio when you can have a separate CPUs deal with it. if there was only 1 CPU the game would have to sacrifice game quality to be maintained centrally or be insanely slow. by separating the systems you can have great gameplay mechanic, fluid video processing, and multi voice sound all happening concurrently, processed separately and being merged together at the end for the user to experience.

Yes i know this , this is common sense

My question is why was dig dug, frogger, etc.

They don't see like very hard and difficult game

The only thing i can think of is that they used higher quality Video ROM chips and higher quality sound chips is these games which you needed to use a CPU for each to drive them

Does Dig Dug and Frogger use different VIDEO ROM chips and SOUND chips compared to other arcade games?

[ed12]

this has been explained to u serveal time's
here is shawn's reply to u,follow it and treat it as the bible when u come
across multi processer unit's

>as for your original question about 3 CPU's...

why waste gameplay CPU cycles having to deal with video and audio when you can have a separate CPUs deal with it. if there was only 1 CPU the game would have to sacrifice game quality to be maintained centrally or be insanely slow. by separating the systems you can have great gameplay mechanic, fluid video processing, and multi voice sound all happening concurrently, processed separately and being merged together at the end for the user to experience.<

ed

[SavannahLion]

They don't see like very hard and difficult game

Stop right there. The above statement alone will put you squarely in the moron camp with no hope of return.

It's already obvious you don't understand any of this. But it's now patently obvious that you have no business even messing around with any computer of any type on any level if you have that mentality.

If you have any hope of understanding anything at all about any of this, that line of thinking needs to go away.

[lilshawn]

compared to modern day computers, yes, digdug could be ran on a single CPU solution. even a crappy atmel AVR could run it.

but at the time the z80 was basically IT. and you were very limited on resources with said processor.

take this for comparison.

if you've ever played space invaders... you know how as you kill off the enemies it starts going faster and faster? it's not because it's programmed that way... it's because the CPU has less and less sprites to move. the speed increase is a happenstance.

The CPU that space invaders used (the 8080) was replaced by the Z80 because as games got more complicated, CPU's needed to improve. eventually the z80 wasn't good enough to do EVERYTHING, so multiples were used to spread the load out over multiple units.

[Ken Layton]

"Dig Dug had 3 three Z80 CPU's why?"

Ok, I'm going to say it and shout:

WHO THE ---fudgesicle--- CARES?

I've had enough of this troll. Let's stop feeding it. Time to use the "ignore" feature of the forum.

[SavannahLion]

even a crappy atmel AVR could run it.

With or without an AD723 or AD725?

You can certainly try with the Uzebox 

[vanwatson]

The CPU that space invaders used (the 8080) was replaced by the Z80 because as games got more complicated

The only difference between an 8080 and a Z80 was the clock frequency limit

The 8080 was an 8bit processor
The Z80 is an 8 bit processor

The only difference is the clock frequency limit on the 8080 was at 2MHZ

The Z-80 had different clock frequency limits from Wiki
For the original NMOS design, the specified upper clock frequency limit increased successively from the introductory 2.5 MHz, via the well known 4 MHz (Z80A), up to 6 (Z80B) and 8 MHz (Z80H).[12][13] A CMOS version was also developed with specified frequency limits ranging from 4 MHz up to 20 MHz for the version sold today. The CMOS version also allowed a low-power sleep with internal state retained (having no lower frequency limit). The fully compatible derivatives HD64180/Z180[14][15] and eZ80 are currently specified for up to 33 and 50 MHz respectively.

[Malenko]

if you're an expert, why are you asking us anything?

[SavannahLion]

if you're an expert, why are you asking us anything?

The next step is he's going to call us a bunch of morons, then present oodles of information supporting his, "parallel port is better than USB" argument.

He kind of skipped ahead to the, "I'm not listening to you," stage, but that's alright.

Afterall, he is the blazing expert on 8080 and Z80 architecture, having never actually programmed or designed anything for those chips. Far more so than any of us that actually made the effort to read and understand the design documents.

Which reminds me, did I ever get that Z80 compiler? I better go check, I got distracted programming that ARM CPU.

[ed12]

well at least the @ is reading.....
abit to fast for his own good..imho...but he is doing it,which in-it's-self is a hudge step,again imho

8080 was 1 of the first cpu's
z80 is a few year's behind it
ie 8080/8081 first,3year's maybe 4
then the die tech caught up to cmos/nmos
hence z80 and up
now u really want a wacker,there is a reason they went away from nmos..
read up on the fact why they did,and u will better understand the design's
and before u even chime in speed i will tell u that is not the reason >period<
there is a tech reason,read away..it will expose it's self

ed

[vanwatson]

So it has nothing to do with the clock frequency limit?

It's all about Nmos compared to Cmos?

Because the 8080 and Z80 are both 8bit , 8 data lines, 16 address lines
The 8080 doesn't have a NMI input
The only different I see is the clock frequency limit

if you're an expert, why are you asking us anything?

I'm not an expert, that is why i'm asking, i'm not here to fight just to understand more about arcade logic boards

[ed12]

ok so far so good
now find the reason

>It's all about Nmos compared to Cmos?<

ed

[vanwatson]

NMOS Disadvantages
1.) Slow Transition from low to high
2.) High in Noise
3.) High Power Consumption
4.) Higher Leakage

At one of my jobs they used NMOS Eprom chips but switched to CMOS chips because of these problems i listed

[lilshawn]

soooooo....

...

...for those reasons they changed the architecture.

the increase in operating frequency was a happenstance of the change to faster switching CMOS.

[SavannahLion]

At one of my jobs they used NMOS Eprom chips but switched to CMOS chips because of these problems i listed

And you couldn't put two and two together?

I struggle to believe you.

[vanwatson]

for those reasons they changed the architecture.

Change what architecture? 8 bit is 8 bit

What do you mean by changing the architecture

the increase in operating frequency was a happenstance of the change to faster switching CMOS.

Yes true, NMOS has a slow switching response time

NMOS needs a higher +VCC power operating point, NMOS draws more current
CMOS doesn't draw much current 

NMOS Eprom have issues with keeping storage and memory stored

[lilshawn]

you know not the difference between nmos and cmos technology?

http://bit.ly/1IQAXWu

[ed12]

i will throw 1 out there for u
see if u can find the reason beside's

>NMOS Disadvantages
1.) Slow Transition from low to high
2.) High in Noise
3.) High Power Consumption
4.) Higher Leakage
<
and the logic its-self
            ^^^  clue there

ed

[vanwatson]

well the logic threshold levels are different and plus there is a "voltage drop" going through an NMOS chip

[ed12]

freg u are so colse,i can taste it

>well the logic threshold levels are different and plus there is a "voltage drop" going through an NMOS chip <

ok a bone here..last 1..and u should have it

nmos is what logic ? cmos is what logic  ?
                    ^^^                       ^^^        clue

btw i am not beening mean i just want u to learn

ed

[ed12]

my z80 specific handbook is mia for the sec.?,but my master handbook of
micoprocessor is beside me

zilog/intel came with 2 dif z80's  there was a die error >intel-side<
and olny happened to the frist lot..hence nmos/cmos >they were to be all cmos<


u can tell spec's by seeing if they go tristate >z80/80a< do..
..they did recall the frist lot..but not fast enough..

handbook by >tab 1299<..if u can find it
it is written by charles k. adams
blue ridge summit
my print is 1981

this hand book cover's
from 4004 to tms9900

ed

[vanwatson]

NMOS
1.) N-type metal-oxide-semiconductor logic
2.) MOSFET 

CMOS
1.) Complementary metal–oxide–semiconductor
2.) CMOS uses complementary and symmetrical pairs of p-type and n-type metal oxide semiconductor field effect transistors (MOSFETs) for logic

An advantage of CMOS over NMOS is that both low-to-high and high-to-low output transitions are fast since the pull-up transistors have low resistance when switched on, unlike the load resistors in NMOS logic.

NMOS logic is Negative Logic
PMOS logic is Positive logic
CMOS logic is Both Positive and Negative logic 

[ed12]

congrads 
now understand it..
and it explains your clock
 aNMOS
1.) N-type metal-oxide-semiconductor logic
2.) MOSFET 

CMOS
1.) Complementary metal–oxide–semiconductor
2.) CMOS uses complementary and symmetrical pairs of p-type and n-type metal oxide semiconductor field effect transistors (MOSFETs) for logic

An advantage of CMOS over NMOS is that both low-to-high and high-to-low output transitions are fast since the pull-up transistors have low resistance when switched on, unlike the load resistors in NMOS logic.

NMOS logic is Negative Logic
PMOS logic is Positive logic
CMOS logic is Both Positive and Negative logic  lso<

also it explains your tristate
think it this way,when cmos is turned off it is >off< >tristate<
as to 1 of your question's that is the answer



ed

>

[vanwatson]

True the clock signal has to be slower for NMOS because of the switching response of the NMOS transistor

That's why I said the only difference between an 8080 compared to a Z80 is the clock frequency limit

also it explains your tristate
think it this way,when cmos is turned off it is >off< >tristate<
as to 1 of your question's that is the answer

True, NMOS and PMOS don't have a tri state or OFF , there is always current flowing even in the idle or off state

I think this caused address line busses errors , data lines busses errors , control line buss errors Because it was sinking and draining the current and voltage from the buss lines back into the NMOS chip pin to ground

[ed12]

and ---steaming pile of meadow muffin--- it also answered your 11 amp question...u thunk ?
again thk u for reading...
now i move u back a seat or 2 and let another person in for classe's
as u now know how to study...frist persent the question at hand..
and olny 1..do not answer a answer with a question..it is rude and pee's most
@'s off...i did my time teaching so i can see it better...

basic theory for microproesser's state's the lower the current the faster we can switch
>clock</>clk<,oh ---steaming pile of meadow muffin--- i have head room,why do we shove a gate or to in here.?
hum wait home's,i want 3 interrupt's..ok u can have 3
show me the :machine: code and we will make er happen

logic

ed