Vulcan-74... An Epic 6502 Powered Game Computer Made of 1980 Logic Parts!

Radical Brad

Garage Hacker!
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Sometimes, I enjoy hiding in my nerd cave, rewinding time!
This thread is here for those who want to follow this build.
When I make updates, you can get a notification via email from this thread.



Here is a link to the full Build Log on our DIY Tutorials Page...

Vulcan-74 Build Log
Last Update : March 31, 2019

Cheers!
Radical Brad
 
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Axedale, Victoria, Australia
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axerail.coffeecup.com
Where do you get the time from? I have a friend, when asked the same question once, who said, "It is simply the choices we make every day."
I am either not making enough choices or those that I am making are simply wrong.
I stumbled across the Cat5 cable trick many years ago. Great stuff, and solders well too.
An electronics element seems to be gathering speed on the Atomic Zombie forum.
 

Radical Brad

Garage Hacker!
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Messages
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Kakabeka Falls, Ontario, Canada
I always answer that one the same way...
  1. Don't watch TV.
  2. Only have productive hobbies.
It's amazing what can be done the same amount of time it takes to sit slack-jawed suffering through an episode of Survivor!

I am going to add a lot more tech as soon as I have the time.
Everything on my old LucidScience.com dumping ground and a bunch of new projects I never posted anywhere.
Will probably keep then in my "Hacks" section.

Brad

Where do you get the time from? I have a friend, when asked the same question once, who said, "It is simply the choices we make every day."
I am either not making enough choices or those that I am making are simply wrong.
I stumbled across the Cat5 cable trick many years ago. Great stuff, and solders well too.
An electronics element seems to be gathering speed on the Atomic Zombie forum.
 
Joined
Feb 20, 2013
Messages
172
Location
Axedale, Victoria, Australia
Website
axerail.coffeecup.com

Radical Brad

Garage Hacker!
Staff member
Joined
Mar 13, 1999
Messages
5,517
Location
Kakabeka Falls, Ontario, Canada
Yes, I remember talking to the builder way back when it first came out. I was very impressed by the data collecting he was doing. At the time, I think the bike had another name along the lines of Microship or something like that. He jammed a lot of big gear on that bike for sure!

Brad
 
Joined
Feb 20, 2013
Messages
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Location
Axedale, Victoria, Australia
Website
axerail.coffeecup.com
WinneBiko I and WinneBiko II, followed by BEHEMOTH, then came Microship (was also the name of one of his websites), and then ...
Have got to give him credit for the technology and the way he used it, and the intestinal fortitude to pedal the thing around the countryside. Must have been one hell of a task at times.
I read/viewed all I could find on the matter and it gave me a few ideas, but I don't have the resources that he did.
 
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Hi, I really appreciate the work that you have done great work to make this game. You have used all your logic and tricks to make such a creative game. Anyone who wants to get the information related to this field, they can refer to it. With such good techniques from our mind, we can do many things in this world. This post will be motivational for us to understand technical concepts. I am a Professor but my hobby is to write articles and blogs in my free time. I really appreciate (stupid spam link removed) for providing me knowledge related to writing on any topic.
 
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Radical Brad

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Sorry folks for allowing the parasite above to sneak through the registration system.
The link went to some essay writing service, and it was one of the worst I have ever seen. A real joke.
I have a new registration page to complete that will lead these idiots on a wild goose chase, but won't have time to finish it until fall time.

This is what I think of spamming losers like this one...

https://www.atomiczombie.com/spammers/
 
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Brad, your project is super cool. I'm a little surprised you don't have more of the homebrew computing scene commenting on this thread. As far as I can tell, you're undertaking the most ambitious 74xxx project I've found online.

I learned about you through the Gigatron developer's slides. They built their no-CPU-IC TTL computer after being inspired by Ben Eater's videos. While they did prototype on breadboard, they ended up producing a kit using a PCB. They apparently discovered you from your YouTube videos on bit banging VGA from TTL. You may have also inspired Ben Eater, since he's now producing a series of videos on bit banging video from TTL.

I'm currently building my second Malvino SAP-1 style computer (although moving toward a SAP-2 feature set) and I had a few questions. I may have missed the answers in your posts, so pardon me if I'm asking something you've already answered elsewhere.

1. Where do you source your clock crystals from? I ordered a 14.31818 Mhz HC-49/UA from Jameco, but don't know if it'll do what I want, yet. I have never worked with crystals, only timer ICs.

2. Are you familiar with Johnson & Graham's book "High Speed Digital Design" ? Roughly, what problems of that class do you run into / have to tackle at the 14 Mhz scale on a breadboard? (Talking about things like line reflection, cross-talk, etc.) My previous computer ran at sub 1khz, so moving to NTSC speeds is daunting. The concept space gets quite a lot larger, as well. Maybe your answer can help me prioritize what to think about when I run into trouble. (Running into trouble is good, for me, since debugging a problem is how I learn. I was never good learning equations off a textbook without applying them to a problem.)

3. Is there any particular debugging gear you recommend, such as a particular logic analysis tool?

4. I notice you're using 74HC ICs. I'm currently working with 74HCT - which is the 74LS compatible CMOS variants. Is there a particular advantage to HC over HCT? Are you running 5V into your boards? I notice that HC has a lower bound on operating voltage than HCT.

5. Where do you source your metal for the baseplate? I assume given your bikes/trike builds that you have the tools to cut this yourself?

Your SRAMs are wild - lots of effort going into those - but they look like a work of art when completed.
 

Radical Brad

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Hey thanks for the comments!
I should probably feel lucky that this thread hasn't exploded yet, but once Hackaday picks it back up it probably will.
My original V74 thread here went over the top a few times...

http://forum.6502.org/viewtopic.php?f=4&t=3329&sid=bf93658bb128b01314bd32ccaba3dffa

128,000 views, which completely surprised me actually. Must still be some interest in the old iron!

Now that farming has taken my time, V74 is on vacation until this fall, but then I intend to keep it evolving as planned.
I am very close to laying down the video system, which will be my most complex and powerful one to date (it if works)!

I look forward to seeing your work, hope you start a thread for it right here in "Tech Talk". Yours would be the first besides this one.

Here are some answers to your questions...

1) I get almost everything from Digikey or Mouser. What you want is a clock oscillator IC unless you intend to roll your own oscillator circuit.
This is the type I use on all of my video based projects...

https://www.digikey.ca/product-detail/en/cts-frequency-controls/MXO45HS-3C-14M31818/CTX752-ND/1801867

These are rock solid, and will not drift. Can be used to clock TTL or CMOS, and also available in 3.3v.

2) I have several similar books, and when I do something "proper", I follow the rules and guidelines of such wisdom.
Having said that, I break all of the rules in my own lab, especially with these massive high speed boards.
No doubt, you have heard what I have... nothing over 1MHz ever works on a breadboard.

False!

There are things you can do to make your life easier on a breadboard, such as placing subsystems together, keeping paired all bus lines the same length, and knowing all worst case propagation delays for all of your ICs. I read the propagation delay parameters before anything else on the datasheet. When you run too close the bleeding edge of acceptable propagation, rethink your circuit, perhaps with a 74HC574 data register in there to realign all signals on the next clock cycle. I do that a lot as well.

Crosstalk isn't so bad usually, and ground bounce or reflections can be kept under control by planning your IC city carefully. HC logic is a good choice because it has a slow slew rate and ringing is minimal. Add even one 74AC gate though, and you are up the creek!

That massive board of mine works great, and the original V74 was running at 40MHz without any problems at all. It actually pulled 640x480 VGA in the first version.

3) I only own a basic oscilloscope.
If something fails, I prefer to look at it and figure out why rather than letting a tool do it for me. I have learned most of what I know that way.
I have never owned or used a hardware or software debugger for any project, not microcontroller or FPGA.
if my code fails, and I really get stumped, I walk away and go sit with a pen and paper. That always does the trick!

Keep in mind that my life is based on doing as much as possible with as little as possible, so it may not be the sane way to do things!

4) 74HCT is a level translator that allows the lower voltage that TTL delivers to live well with modern HC logic.
Unless you have real TTL talking to CMOS, you only need HC logic, not HCT.
I do use HCT on my VIC-20 to FPGA project though becasue TTL is often just below the proper CMOS level.
This one also used HCT logic between the 6502 (TTL) and modern HC logic...


Another good variant is 74LVC, which will allow 5v TTL to interface with 3.3v CMOS. I am also using that on a "secret" VIC-20 project.

5) The 1/4" thick aluminum plate was just scrap, but any steel supplier could get you small pieces like that.
I cut it with a hand held angle grinder and then just drilled the holes with a hand drill.
Don't cheap out on the breadboard panels. Twin Industries all the way!

Those SRAMs were so fun to make! Did them when I had the flu and had to sit on the couch all day.
Hope to have them on the V74 board before the end of this year.

Cheers!
Brad
 
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