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Altair 8800 Micro prototype

V

vbriel

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Ok, I've been working on a new project, a clone of the Altair 8800. Since Grant has already done an exact replica, I thought I would do something different. I pulled out my shrink ray gun and made a reduced size replica I call the Altair 8800 micro (catchy huh?) It is 10X3 by 9" deep and fits in your hand.

ALTAIR2S.JPG


The project is based on a ATMEL AVR microcontroller as the heart of the Altair. I wrote my own emulation of the 8080 CPU and 6850 serial controller. The front panel is also simulated and you can exam deposit run/stop all from the front panel. Included onboard is the pocketerm terminal so you have VGA and PS/2 ports for I/O. Right now I have the BAUD rate set at 9600 but will be bumping that up soon too. The CPU speed is only about 60% of the actual Altair for the moment. I am working on speed enhancements now and should have it to 100% shortly.

ALTAIR3S.JPG


Recently I got the CPU section working where I can load and run both 4K and 8K BASIC and it appears to be bug free but there is still a lot of debug testing to do. I will attempt an expansion port but I'm not going to promise exact timing specs. It would be cool to make it expandable! To make it better I would need to create an I/O port pin that indicates access is being attempted to an I/O port and the RD/WR signal would indicate if it is attempting a read or write from that port.

More project info along with pictures are here:

http://www.brielcomputers.com/wordpress/?cat=11

I have a video up on youtube but it didn't turn out so I'm going to redo that this weekend. I should have these available by this summer! Other variations will follow including a full sized front panel.

Let me know what you guys think, this is my first attempt at CPU emulation.

Vince
 
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Nice work, Vince!

Why the 6850 UART, though? My recollection is that the MITS 8800 serial card used one of the dedicated UART chips (TR1602 or equivalent). 9600 I believe, was pretty much the top speed--it was the top speed for most terminals of the time at any rate.
 
This is possibly one of the nicest idea for a clone!

It's, seriously, quite... cute. Looks like something you could buy as a souvenir... "Revive the Altair 8800 with this new, full-functional clone..."
Just, awesome.
 
Just hope you'll offer a keyring attachment. :)

Nice job as usual, Vince.
 
Now I wonder how long it takes until someone builds a mini replica of the ADM-3 for this thing.

Anyway, it'd be interesting to see some kind of USB port to use a modern PC as a terminal.
 
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@Chuck - The SIO2 used a pair of 6850's. This was the most common card that I'm aware of for the Altair's. Reconfiguring the BAUD rate on the fly with the AVR is no easy task so I'll need to decide on a set speed to make things easier. I know whatever speed I choose, somebody won't like it :)

@NsMn - Even my wife thought it was cute, so I knew I was onto something. Get this, I've had this idea in my head for 5 years now. I've been trying to put it into hardware form for a while. I'm really glad I decided to bite the bullet and do it with emulation. When I first got the front panels in, I didn't have my boards yet, I couldn't wait to get one built. Very fun. Keep in mind I put my PockeTerm design onboard as well so there is actually a built in terminal like the ADM-3! I'm considering a disable terminal jumper feature and adding a serial port so you can use a PC as a terminal. They make serial-USB cables for about $5 on ebay.

@ahm - I'll try and do something smaller next time :) I'm going to try and make it out for the next VCF east for people to see in person. If things work out, I'll have some ready by summer.

@kyeakel - Kits are probably going to be $199, assembled and tested around $249~ The kits will include the case, front panel, rear panel, PCB and all components. You will just need to add your power supply, keyboard and monitor. I've done everything I could to keep the concept affordable.

Vince
 
vbriel said:
@Chuck - The SIO2 used a pair of 6850's. This was the most common card that I'm aware of for the Altair's. Reconfiguring the BAUD rate on the fly with the AVR is no easy task so I'll need to decide on a set speed to make things easier. I know whatever speed I choose, somebody won't like it :)
Click to expand...

That's pretty surprising to discover, Vince! I was under the impression that the SIO1 would have been the dominant card, at least for the original 8800. Remember that MITS included it in the $1000 "special deal" package--(1 SIO, 2 4K DRAM, CPU) for the 4-slot 8800. Now, if you include the 8800B, that could be a very different story. (I still have my SIO1, BTW).
 
Vince,

First - Amazing, great work. I love your kits. Emulation is an interesting idea.

Second - Could toggle switches be used for the front panels (they look like slides to me)? And a custom metal case would be really nice :)

Third - Will you have one at the Vintage Computer Festival East in September ?

-Crawford
 
Wow, I tried to post and it just didn't go through, I'm gonna try again here...

Crawford, been a while! I'm going out to electronic surplus today, should be fun! I choose emulation because it fit what I wanted to do. Every other option just added too many components or I had other issues. This option keeps the price low and the components to a reasonable level.

The toggle switches on this little case really stuck out and were just too big. Even mini toggles were just huge. Yes, I'm using slide switches, it was a tough decision but one I think gave it the best appeal. Not sure if I've found the final ones I'm going to use, I have pages on pages of catalogs to go through first. I plan to offer a full sized panel in the near future (this year) that will have the standard Altair style toggle switches. This way, you can have the realistic feel or the fun micro version.

I really want to show it at the VCF east this year, a lot depends on the economy, job, etc. As long as things remain the same, I can be there!

@Tez - Thanks!

Vince
 
If I had enough money I'd buy one of those micro replicas; it's done really well from what I can see of the pictures.
 
Looks like I have to be a little child and get a "toy" for my birthday again.
 
Well, that enthusiasm is what keeps me going on this stuff. That was the same feeling I had towards kits in the late 70's early 80's.
 
I have to say.... I somehow prefer the gray case and the sliding switches. But maybe just because there isn't a real "original style" case with toggle switches. Also, I think operating toogle switches would be far more annoying to operate if they're mounted to a thin piece of plastic or metal like in this case.
 
Vince,

OK, I'll take it as a challenge to find not only small toggles, but really really tiny toggles! I think you're on the right track, though with the small front panel. I still want to make a scale FP for the SBC6120.

What is the scale of the mini-Altair? 3/10ths or something like that?

Anyway, please don't take my question about the switches as criticism, it is still truly awesome!

-Crawford
 
Wow, thanks for the help guys. I should have done a shout out for this a while ago. Chuck, I have to look at the size a little closer but they look close to what would be needed. The real issue is the price. Even in qty those are $3-4 each. We're talking about $75 just in switches which really jacks up the total cost of the unit.

Criticism is what I need Chuck, it's how I work out the final details. The switches are definately an issue I have to resolve one way or another. To put things in perspective, the slide switches are about $.35 each. I might hit the target price still if the switches are under $1 each. If you are going to do a FP for the SBC6120 look at how much the paddle switches will cost! The switches are always why front panels cost so much. People don't realize how much switches cost.

Vince
 
Vince, the switches weren't cheap when the Altair was new! Let me dig around a bit and see if I can locate a good deal in some of the surplus markets--you never know. But genuine toggle switches seem to be going the way of the dodo in the commercial world--everyone wants buttons.
 
vbriel said:
Wow, thanks for the help guys. I should have done a shout out for this a while ago. Chuck, I have to look at the size a little closer but they look close to what would be needed. The real issue is the price. Even in qty those are $3-4 each. We're talking about $75 just in switches which really jacks up the total cost of the unit.
Vince
Click to expand...

When I was looking for switches for the USB Altair front panel Howard and I designed, ISTR that Future Electronics had the best price for the C&K toggles I used. Having said that, they were still about $2.50 +/- per switch @25 units. A large-quantity purchase would make some sense to drive the unit cost down, or look to Hong Kong suppliers like Futurlec (which is different than Future Electronics.

Great job, Vince. It's an awesome project.
 
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