I'm glad to hear the project is still ongoing, ie, not dead! The homesteading sounds very attractive too. We have one other member I know of who's doing that now too.

Have you actually measured the propagation delays on the ICs? (They'll change with temperature and load capacitance too.) The delays you list are less than what's in my National Semiconductor data book. Even the typicals listed are more than you list. There's no minimum specified though.

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

Thanks!
It's a good life for sure. Everything I have is worth so much more now, especially my free time.

Yes, I have studied the datasheets for all of my ICs, and I usually take the typical rating at 5 volts.
I know that this is not guaranteed, and for sure I have been victim to this at one point or another.

With my new asynchronous design, it will no longer matter the value, just the predictability.

I am expecting that a handful of buffers all marked with the same TC74HC245APF-ND manufacturing code to give me the same 10ns typical delay. If this delay is longer, then I expect all of them to be the same.

If I do find that there is say a variance of half a nanosecond through all 32 of the same exact make and model of gate, then I can buffer the signal at the very end using one last clocked register set and a properly synced clock signal.

I have used this design in the past, and I called it "3 in the pipe" as I was feeding a signal through a circuit so quickly that there were 3 sets of data in transit at one time before making it to the other end.

What was interesting about this test design was that I could pump a 50ns SRAM at it's maximum rated frequency of 20MHz, and get perfect video out the other end. Total propagation through the entire circuit was a whopping 400 nanoseconds, and it was fully asynchronous. I used only gates form the same manufacturing run so I could control the propagation.

I will be considering the placement of all ICs and wire length in this new design as well.
It should be a fun exercise in making a breadboard reach the next impossible goal.

Brad

I realize it's been a while since I posted any updates on this project.
The project is still very active, but it has "evolved" somewhat.

Everything up to this point was mainly testing on the Audio and Video Hardware, and I have finally settled on the general design, which is 400 x 600 resolution with 4096 simultaneous colors.

I have also had the chance to test the 65C02 IO decoding system, which worked very well. So I now have a powerful 6502 powered computer system built with nothing but 1980's era logic gates and simple static RAM.

The challenge now became... how do I develop code, assemble, save, and load?

The original idea was to just drop in a PS2 keyboard and SD card, or some kind of USB host chip like the Vinculum II.
Something about relying on modern hardware didn't feel right to me.
It would be like dropping a 57 Chevy on top of an Impala frame... not my kind of Hotrod!

So I have recently rediscovered my favorite computer of all time, The Immortal VIC-20!
I have decided to rename the Vulcan-74 System to The VIC-2000 Expansion System.

This entire system will become an Expansion Cartridge for my stock VIC-20!

The VIC will handle the Operating System and IDE / Assembler, and the 65C02 on the board will run the code, talking directly to the logic board. This way, I am staying "retro", and can start to enjoy the first computer I ever owned again. The VIC will remain completely stock, and talk to the new hardware only through the Expansion Port. All 6502 code will be developed on the VIC-20 screen, and the 65C02 on the board will display its output from the assembled code on a separate VGA monitor. Yep, dual display VIC-20 in charge of 16MB of SRAM!

Because of this course alteration, I have continued my build log over at the VIC-20 forum "Denial" here...

http://sleepingelephant.com/ipw-web/bulletin/bb/viewtopic.php?f=11&t=8734

I'm sure some of you are members there as well, and it is a great wealth of VIC-20 knowledge for me.

This entire project will be re-posted on my own site in much greater detail when it is done "some year", but for now you can continue following the trials and tribulation on the link above.

Here are some highlights as I reacquaint myself with the inner workings of the VIC-20...


VIC-20 Draws 400 x 300 color bars in Basic.


Initializing the SyncGen Hardware and Code Memory.


Quick video showing the test setup...

https://youtu.be/R1eGVoCmE5k


VIC-20 (top section) merges with Vulcan-74 (lower section).

Thanks for all the comments and suggestions during this part of my design phase.
I will pop back in here once and a while when this project reaches new milestones.



Looking forward to using my VIC-20 as my main computer again.
Having that second 65C02 and VGA output is going to be fun.

Cheers!
Radical Brad

43 pages , no single schematic or code .... or anything !
What is the point ? .

There isn't one.
I did this because it was fun.

The new blog I started will probably have hundreds of pages.
But again, there will be no point.

Hope that clears it up.

Brad

It reminds me of the summer our younger son was 16 or 17 and rode bike 1300 miles (2100 km) in one month, and did four rides of 100 miles or more in one week. A family member asked him, "What was your goal? You don't do that kind of thing without a goal." Daniel replied, "Well, I had a lot of fun!"

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

I hope it still is. I have fun following along, even though the chance of me copying or buying any of your creations is extremely low.

Please let us know when you're ready to share. I definitely want to check it out. I am envious of your broad range of skills and your creative energy.

Crystal clear. Thank you, sincerely.

Mike B.

Thanks!
Glad my ramblings have been good for at least entertainment value to others as well!

I posted the link to my blog continuation in one of the above posts.
Here it is again...

http://sleepingelephant.com/ipw-web/bulletin/bb/viewtopic.php?f=11&t=8734

Brad

It's a hobby, so there doesn't have to be a goal, point, or purpose, for that matter. If there is any point, it is that he could do it.

_________________
x86?  We ain't got no x86.  We don't NEED no stinking x86!

Great work, Brad.

One thing that struck me was how few columns there are on the text screen. I don't remember the VIC-20, and the only 6502 machines I used back in the day were 40 column.

How does it feel using such a narrow display for coding? No secret POKE to get into 80 columns?

Thanks!

Yes, the VIC only has 22 x 23 characters!
You can expand that to up to 26 x 32, but being NTSC, it draws in the over-scan area, which means many monitors will clip the image.
I tried.

It's actually not so bad when you consider an assembly editor.
Instructions are so short, that I will probably still have too much white-space in my listings.
Add that to the fact that I my eyes are 11 years older than the vintage VIC... it's actually good to have big text!

Brad

Just wanted to say that the Spirit of Vulcan-74 is still alive and well, and most what was designed in this thread is now being used in my "final" 6502 project called VIC-2000...

http://sleepingelephant.com/ipw-web/bulletin/bb/viewtopic.php?f=11&t=8734&start=135

The reason I decided to attach the entire system to the VIC-20 expansion port is to allow all 6502 coding to be done on an age appropriate platform. The 6502 / Logic based GPU system will still be blazing fast, but I will be coding and assembling on a 1981 computer rather than some cheaply made PC of the day!

The Vulcan core has actually grown up a bit as well, and now features a 12 bit color data bus as well as increased VGA resolution. I still have a few years of development to go, but have at least settled on the final specs and goals.

I also intend to install a secondary 65C02 in this system so that the VIC-20 has a companion processor!
This site is still a great wealth of info for me on this project, so thanks again for keeping it alive.

Oh, and something that was discussed earlier was how I found a 65C02 to be "noisy" in my video system as compared to AVR, PIC, ARM, FPGA, CPLD, and some other processors using the same design. The 65C02 put out noise that was visible as faint lines on my video.

Just to report back... the NMOS 6502A in the VIC-20 also does this!
I am looking at special filtering at my DAC section to reduce this issue now.

Cheers!
Radical Brad

Not sure if it is cool to be updating this while it continues on a different site?
I was never one to really understand web manners, so here it goes anyhow.

I finally broke the 640 x 480 x 4096 barrier!!!

This is something I have wanted to do (and tried) since day one of this project.
At 25MHz and 16 bits of data, it almost seemed that I hit the breadboard barrier.
But last night and a total rewire (again), I finally did it.
Totally stable all the way.

http://sleepingelephant.com/ipw-web/bulletin/bb/viewtopic.php?f=11&t=8734&p=99284#p99284

Most of the original Vulcan-74 hardware posted here will be included in this VIC-20 project, but it has been enhanced to support 640 x 480 using a 16 bit data bus for 4096 colors. I also have plans for true multitasking (extra 65C02), and a dedicated MOD-like player, all done in 7400 logic.

So this project is still an official 65C02 project (because of the dual CPU), but it is being made as a dedicated VIC-20 expansion system.
The only reason I am posting on the other site is because the VIC-20 is really the reason for the project now.

I still lurk around here (a lot) to see other cool projects and learn more about the 6502 as I hack away at this.

Cheers,
Brad

Hey, look what my VIC-20 drew today!...



https://youtu.be/EIghk1BUG98

The full post...

http://sleepingelephant.com/ipw-web/bulletin/bb/viewtopic.php?f=11&t=8734&p=99426#p99426

Brad

Just doppin' in to say that I am still kickin' and my VIC-20 project is still on the go.
I have been super busy with Homesteading work and my day job.

Had all kinds of hosting issues as well, so when I have time I will try to get the photos back up.
I will be posting something new again... maybe this winter.

Cheers!
Brad