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Altair 8800 Micro prototype

Vince,

I understand making a price point (and even being called Chuck, that's a new one). Even if you produced the kit with slide switches, I'd buy it. I'd also try to retrofit toggles on my own build and build a metal case too. (I've been to too many scale model shows I guess). You've met 99% of what 99% of people would want, I'd encourage you to forge ahead.

But remember, lots of people spend $400 to do a front panel for the SBC6120, which cost about $150... If/when I build a scale FP for the SBC6120, I would even build scale paddles in orange and yellow, and that wouldn't be easy, or meant for anyone without my particular version of OCD...

This is a wonderful project, and one I look forward to building. I think I've built all of your kits (except for the Apple 1 replica). Just sharing where I'd go with it, if it were available today... (I think I just customized something that doesn't exist yet!)

-Crawford
 
Submini toggle switches can be had on the retail market for less than USD$1 and probably less if ordered from a Chinese vendor (they don't make them in the US, you know).

At that price, they tend to be a lot more practical.
 
Sorry Crawford, must have been tired. So much coding lately, I'm getting a little red eyed.

@Chuck, if you can find me a link to a place, I'll check them out. I would definately prefer super small toggle switches to slide. I just couldn't find anything that fit the price/size catagory.

Ok, so today I added a feature to choose your filename to load on power up. This lets you choose what you want loaded in memory at power up. You can choose 8K, 4K, enhanced basic or some monitor program. To avoid it asking on power up, you can flip a switch on the front panel (aux) and remove the SD card before powering up. Does this sound too complex?

Vince
 
vbriel said:
@Chuck, if you can find me a link to a place, I'll check them out. I would definately prefer super small toggle switches to slide. I just couldn't find anything that fit the price/size catagory
Click to expand...

Check your PMs. We can take this offline and discuss your needs precisely. Maybe I can find something for you.
 
Probably obvious but you were talking about expansion ideas. It's probably unfeasible and I'm completely unfamiliar right now with the pinouts of the S-100 bus but I think the obvious (and coolest) expansion port if possible would be to an s-100 external bay/kit. *IF* it was possible to use some common connector to get all the data you'd need through the cable for the bus (or separate project time) but that'd probably be useful if compatible with original gear and a huge bonus if one could get it to work with your replica.

Could just be a pipe dream and certainly would take some free time away from ya.
 
Vince,

vbriel said:
Ok, so today I added a feature to choose your filename to load on power up. This lets you choose what you want loaded in memory at power up. You can choose 8K, 4K, enhanced basic or some monitor program. To avoid it asking on power up, you can flip a switch on the front panel (aux) and remove the SD card before powering up. Does this sound too complex?

Vince
Click to expand...

Actually, that sounds like an elegant approach. Beats the hell out of toggling in a couple of dozen machine language instructions! <insert grumbling about how kids have it so easy these days>

I've never seen an Altair power cycle up from cold, but you could have it do that if no SD card was installed...

-Crawford
 
vbriel said:
Ok, so today I added a feature to choose your filename to load on power up. This lets you choose what you want loaded in memory at power up. You can choose 8K, 4K, enhanced basic or some monitor program. To avoid it asking on power up, you can flip a switch on the front panel (aux) and remove the SD card before powering up. Does this sound too complex?

Vince
Click to expand...

Sounds very straight forward and a nice feature.
 
Hi! I have an N8VEM S-100 backplane that might be useful for such a project. It has six slots and active termination. I power my board with scrap laptop/printer power bricks and it works fine as a bench top unit.

It also exports all the S-100 signal pins to four 13x2 dual row headers. Assuming the micro Altair generates TTL level signals just bring them in from the backplane board and would electrically connect. The hard part would be to engage the ATMEGA/Propeller to act as a bus controller.

Thanks and have a nice day!

Andrew Lynch
 
I think if you want S100 bus, just get the N8VEM, it is geared towards that and CP/M. I haven't even considered looking at timing signals and those protocols for external expansion. Everything is internal right now. I'm not saying it is impossible to expand but I haven't even looked at it yet. On the other hand, I do have the 32K RAM connected in a format that would follow the electrical rules so it is possible.

On other points I increase speed a notch with code improvements. A 3:36 min program on Altair32 takes 4:56 to run. I'm getting closer. When I get a little closer I'm going to try a faster crystal to match the speed.

I also added a slow method to download BASIC programs if you want. While you can load/store all 32K RAM, what if you just want to send a text file with a basic program typed in? Well, now you can select a file and it will dump the text file into basic. It isn't very fast since BASIC is slow at a command prompt, but it is an easy way to load files.

Anybody know of a simple monitor program or assembler in a bin file for the Altair? I'd like to try one out and see how it works.

Vince
 
I have another question. Is it possible to add a connector for standart vintage terminals? I know it's kinda useless, but it'd be interesting still.
(I guess it'd be possible if there would be expansion slots ;) ).
 
NsMn said:
I have another question. Is it possible to add a connector for standart vintage terminals? I know it's kinda useless, but it'd be interesting still.
(I guess it'd be possible if there would be expansion slots ;) ).
Click to expand...

It's possible, and I'm considering it. I've made the built in PockeTerm play a larger roll though. Right now, it loads/stores all programs and I'd have to work out the details but I think it is possible to shut down the terminal I/O section. I'll look into it. It will be difficult though because of all the features it does now:

Loads startup program (BASIC)
loads/stores memory
soon it will be able to update firmware from SD card


I'm working on a bootloader for the firmware now that will allow you to update the firmware from a file on the SD card. This will make any firmware updates/fixes really easy, no sending in chips to get programmed!

Saving memory - right now you can backup and restore all 32K RAM in about 30 seconds, not too bad. Still need to work on total overal CPU speed and look at enhanced basic to see what's going on there with math functions. Waiting on some toggle switches to arrive to see if they are small enough to fit without looking too large on the panel.

Vince
 
Just a little update on the project. I have the flash update section finished. Now any code changes just requires the user to download the update and place it in a SD card. I'm working on the front panel redo now. Going to change from the tiny slide switches to toggle switches. I can sit the switches deep enough that only the paddle portion will stick out so they won't look too large. I'm having a new front bezel made now and next week I'll order a new panel pcb. After that it's beta testing time! Roll out target is June. I'll have more info on that when the time gets closer to rollout. I'm really happy that I found switches that were the right price and the right fit. They are a little tight but will work. I'll update pics when everything comes in.

Vince
 
Vince,

Personally I think the toggle switches will make this awesome kit more awesome (awesomer?). Anyway, great job, and thanks for listening. This kit officially "goes to eleven"!

The flash updates sound great, as well as the alternate boot modes. Will you publish the source code for us code junkies that may want to extend or modify bits?

-Crawford
 
I more than likely will publish all the work. I try to so people can learn from what I've done. What's funny is this is a rather large project and I go back to make changes in some areas and I have to remember what I did. I make lots of notes so it usually is easy to figure things out. On the NTSC option of the terminal, you will get full color text. That means you can place characters on the screen in any of ~20 different colors. This makes it a simple color computer now.

Even though you can backup RAM in about 30 seconds to SD card, I'm probably going to add a battery to the design. This will just make it easier to power and go right to work. I'm doing the reworked layout on the mainboard now and will probably put in to have prototypes made next week. I should hopefully have a final prototype in a couple of weeks. Beta testing will happen while I write a manual. That might end up being over 100 pages.

I also put a 40 pin header with standard bus signals on it. I haven't done any testing on the signals to see how they look but if RAM works, I must be close to within timing specs. When I get a chance, I'll fire up an older HP logic analyzer I've got laying around and see how the timing signals look. I'll also have to make some tweaks to the firmware for external RAM/ROM or I/O to be connected. Right now, it always attempts to access the 32K. I need to mod the code so if above $7FFF in memory, it won't activate RAM.

Vince
 
Vince, you're making it too easy! You need to add some additional "realism" to the thing, such as mysteriously corrupting memory when simulating the MITS 4K DRAM card! Or a 300 bps interface with a slow audio cassette recorder that takes 5 tries to load a program without error.

Seriously, good job!
 
Ok, so I got the new front board prototype in today and started building. So far so good. Just as I suspected, the switches really fill out the front panel. Here's a couple of pics of the new setup. The proto front overlay has some errors but they will be cleaned up before production.

altair_new_0.jpg


and here's one so you can see how the switches stick out, not too bad. The momentary step, exam and deposit switches are just the right touch to make it more like the real thing.

altair_new1.jpg


The final mainboard prototype is due in Friday or Monday and I'll start right in on that. Let me know what you think now.

Vince
 
The first one looked good, but those switches are the icing on the cake. Very nice!

How did they affect the price in the end?
 
Beautiful! You do indeed do nice work, Vince.

Of course you can tell from the LEDs and the switches, but it'd be nice to have a picture with something else in it to give a reference for size and scale.

Also, I assume there's room for a holder inside for enough batteries to make it portable?
 
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