QUEST SUPERELF: ONE OF THE FIRST PERSONAL COMPUTERS
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- čas přidán 19. 06. 2020
- Back in the 70's integrated circuits got to the point where a whole CPU could fit onto a single chip. Soon there was an explosion of companies offering a new class of personal (or micro) computers....
This example, the Quest Superelf, was a good example... it takes it's design cues from the mini-computers that preceded it. The 1st user interface is a console which allow code to be written in assembly and directly entered into the memory of the computer.
More details on my blog at electronupdate.blogspot.com/2... - Věda a technologie
First time I have seen a particle wood case for a computer. Thanks for an interesting video.
Awesome! Thank you, so many good memories building my first computer in 1979 before saving enough for an Apple ][+. You are right, learning assembler served me well through out my software/engineering career.
This computer is almost twice as old as me , Beautiful machine.
Had one of these back in 1982. Wish I'd kept it.
I did run the pong program for this into a black and white T.V. Yeah, 256 bytes of memory is not going to get you a deluxe pong game. The video chip dumps the who memory to screen, so the program in memory is actually displayed on half the screen (top half, if I remember correctly), and the pong game is played on the other (lower) half.
If I remember correctly, that 'Q' pin was what was used to feed a general-purpose output. I ran it into a mini-amp with speaker, and programmed it to play a song, all in 256 bytes.
I opted for the Super Elf because of the hex pad. The predecessor, the Elf, was programmed by an array of toggle switches, each representing a bit. Imagine having to flip up to 8 switches for each byte of code you'd need to enter.
A bit late for a reply, but it brings back good memories. I bought the Super Elf as a kit when it was released. Sadly I cannot really remember how much I payed for it, but it must be around 390 Dutch Guilders (the Euro was not even an concept at that time). As I was studying electronics around that time I was using a soldering iron on a daily base, so putting the kit together was a breeze. I have spend many hours in programming that device, and it was a big help in learning machine code.
I still have that kit, and it is in perfect working order. I also have lots of documentation (and programming sheets) stored with it too. It was not actually my first computer, but it was the first that worked flawlessly. Before the Super Elf I had a contraption that was made from TTL logic (SN7400 series), but I never got that working in a reliable way. The computer that came after the Super Elf was the Acorn Atom (also a kit), that I am restoring to full working order at this moment.
This reminds me of a small Z80 project I did in school in the mid 80's called the BIT24 (the 24 standing for C and H respectively) All wire-wrapped. 4 or 6 toggle switches and a 4x4 keypad with 4 seven segment displays. From that device I learned a lot about assembly language programming of the Z80, 8080, and the 6502, all of those had command sets small enough to memorize. Thanks for sharing.
I was just a bit too late for these machines... I came along in the age of "plastic home computers with BASIC built in"... I used to dream of owning a machine with a hexadecimal keypad.
memories.... blinking an LED was a one night high... bit bashing serial to a KSR33 or DECvt102 terminal made me feel like a god .
Don't say anything bad about the CDP1861 graphics chip. It comes from a time when you still could not buy computers in a store. You had to build them yourself and these computers usually had no graphics at all. Getting graphics by simply hooking up a single IC to the processor's bus was a small wonder at the time. No separate graphics memory is needed, because it is designed to use the CDP1802's somewhat unique way to handle DMA. If you want to make a video about the Elf's graphics, you might look for the 'starship' program we traditionally used to test the graphics after assembling the computer. It works with the 1/4 k unexpanded memory. And you might also explain how interrupts and DMA are used here to bring the pixels onto the screen. That was almost the first thing I ever did on a computer, right after letting the Q LED blink.
Did a quick fact check. Per Wikipedia, Radio Shack's TRS-80 came out in 1977 (as an example of a pre-assembled computer) and the CDP1861 was released in the mid 70's. With that approximation for the CDP1861, can't exactly count how many years they were apart, but it was clearly less than five. Either way, you point is supported. I was just curious, because I got my Super Elf around 1980/81, and I sold TRS-80's in the late 70's. Yeah, Radio Shack was my after school job in high school. I never saw (or just don't remember) the 'starship' program. But, I did get the pong program running, with half the screen populated by the program code itself, and the other half showing game play. The only real program I ever created myself for it played music out the Q pin into a tiny amplifier and speaker.
Caught me online, so you get a quick response. The original Elf was published in Popular Electronics in June 1976 and the 1861 was added as a small expansion (just adding the chip and a small modification to the computer's clock) in a later issue, let's say early 1977. Kits like the Super Elf and the Elf II already included it when they appeared. As simple as they were, the Elves had one big advantage: They were cheap and did not need an expensive serial terminal, nor did they need complicated graphics hardware built with TTL logic like the TRS-80 or Apple II.
I would not have gotten started back then. A TRS-80 or Apple would have been far to expensive. I was still a kid with a monthly 'income' of 20$. But I could talk my parents into getting me an Elf II and scraped together some expansions. A good investment. I still have it and it still works.
Awesome video.
I love bragging that my first computer had only 256 bytes - about a tweet and a half! I would love to have another of these...
I remember seeing the Elf at an electronics store in Anchorage, AK and lusted after it but thankfully it was also Apple II time and my entry into personal computers. I had the same "de-capping" thought as another viewer had below!
Now comes the decap...... 😈
The 1802 was quite the processor for its time -- rad hardened, etc.
Do you think it is finally time you graced this with proper address decoders/displays?
In days gone by Technical Educational institutes had similar devices, two per class. You had to write programs to send hello world over UART.... while a second class mate wrote the receive version.... I don't miss these at all!
Doug Demuros Dad?
Great video as always.
At the time I used a CDP1802 for a project simply because it was quirky. Nothing else I knew of that had DMA built into the processor chip. I was also fascinated by the TI TMS9900 with no CPU registers but it was so horribly slow I could never find an application.
Christ... for a moment there I thought you were going to start de-capping.. phew :)
A quick check on ebay shows that these are now antiques and command premium pricing to almost a $1000.00 I think I will not decap :)
All before my time (I grew up with a 386) but still very cool. Any chance we can get an update on the subterranean Raspberry Pi? I have this crazy idea to repurpose a MagSafe connection to keep it powered, or maybe roll my own with some magnets. Also, that iron ring is looking fancy mon ami! did you go to UBC?
Did this on 6809 trainers in...about 2002 😂
It's fun for a short time, but then the tediousness of it quickly becomes apparent. It does definitely give an appreciation for what's going on inside, but in an actual education system it probably shouldn't be stuck with for too long - in my opinion once that appreciation has been gained it's time to move onto learning a lot more newer and realistic stuff before someone's attention span is lost.
👍
Damn I'm old :/
Did you ever acquire the low and high address option parts?
Nope, too expensive
Also, cosmacelf.com/forumarchive/files/Quest%20Super%20Elf%20Documentation/SUPER_ELF.pdf has some nice drawings of the board from figure 13 on, and assembly instructions for the board (physical assembly, not "assembly code"! E.g. "F. Install the two transistors Q1 and Q2. They should stand approximately 1/8 inch off the board. SOLDER")
Of course, the whole document is amazing to read.
So once you've "written" your program (as you just did) is it stored in some sort of ram that gets erased when the machine goes off? (like my TRS-80?) Or how did you store offline and load on this? Thanks!
I think there was a battery backed RAM option... in those days storage was a paper binder full of programs and quick fingers to re-load them.... one nice thing about a 256 byte sized memory
from the SUPER_ELF.pdf I mentioned in an earlier comment, on page 5:
> ... Starting at the upper left-hand corner
> and going to the right, the BAT pair of connections are used for the 2.4V
> standby Ni-Cad battery included in the memory saver option. Next are the
> SW1 connections used to connect the battery to the RAMS (also used in the
> memory saver option)
From the catalog, it seems the "Super Expansion Board" let you use cassettes to load programs. cosmacelf.com/forumarchive/files/Quest%20Super%20Elf%20Documentation/Quest%20Catalog.pdf
> The Super Expansion Board comes with 4K of low power RAM fully addressable anwhere in 64K with built-in memory protect and the hardware for a cassette interface. The cassette feature runs on regular tape using srandard recorders.
Yes, that's it for the basic kit. I never got the adapter to save to audio cassette. I did buy an ASCII keyboard, but never got the UART for that. I was enlisted in the service, just out of high school. I was not making the money for the extras.
@@zenithparsec can confirm above worked... source: I built one.
Very nice.
Can we see the other side of the board?
And there is a typo in the source beside "3A 0E"; it should say BNZ 0x0E, not BNZ 0x10. (I think either you changed the code, or accidentally put the address of the instruction in the mnemonic, instead of the destination address.
Machine code programming FTW!!
The other side of the board isn't too dramatic. If I remember correctly, it's just single layer, with old style solder pads. Nothing like the surface mount stuff we have today.
Room there fro another 2 7805 regulators, just in case you had an expansion card that got you past the point the single wimpy heatsink would keep the regulator out of thermal shutdown. Probably at around 0.5A of current, as your AC input was likely 8VAC, so the regulator dissipated more power than the actual computer itself used
Even more so because the 1802 was one of the first CMOS processors. The logic ICs on the board also were 40XX series or 74CXX series CMOS devices where ever possible. If you can get rid of the LEDs (and probably the LED display drivers) and the voltage regulators, you could run an Elf on batteries for quite some time.
The extra regulators are for:
1) 16 bits of Address Decoding and 4 7-Seg LED’s.
2) Backup Nicad batteries for the ram so you don’t loose the contents of your precious 1/4 K program.
I’ve got several Super ELF’s and the single 7805 will support my custom 32k RAM / 32k EPROM, Real Time Clock, Serial connection and Compact Flash “hard drive” for running ELF/OS but if you chose to install the period correct Quest Super Expansion board, you will need a more rugged power supply and you’d disconnect the original 10v AC adapter.
that really is basic. Nice to look back at some old kit. 👍👍
And he just keeps touching it while it's running.
The chips run very low voltage. 5 volts maybe less. You can get a shock from 24 volts but you need to have sweaty hands. Note personnel experience I have been shocked before and it doesn’t affect me at all affect me at all affect me at all.
@@djwmunro This board has two 2101 static CMOS RAM chips, which are very static sensitive. Definitely wouldn't want to zap one of those by touching it. They're something like $4 each.
@@revengefrommarsNah… These things are extremely rugged. I grew up in the days of non clamped CMOS chips that would fry if you looked at them the wrong way but the parts used in these machines are extremely durable. I’ve handled hundreds of the RCA COSMAC chips and I’ve only fried a single 1802 chip which was absolutely my fault. I’ve done dumb, absent minded things with others that haven’t so much as paused. Handling that machine the way he is, should be fine because he’s away from the address and data lines. The worst thing that would happen is he crashes the program or alters some program memory. No big deal at all.
Wow a bizarre computer with a hex keypad and no Wikipedia page
Well, there is a page for the original Cosmac Elf. But even in that, there's no mention of the Super Elf. There was a fairly substantial mail order supply for these, though. I had the Super Elf and splurged for the special columnar form paper to facilitate writing code, as well as a couple other goodies.
These were advertised in every electronics magazine from about 1976 - 1982. I bought the Netronics ELF II for $99. This one was $107 or $109 if I recall correctly.
Where is the video output?
It looks like it's on the left, slightly down where the gray cable coming out is below the blue capacitor. (This is based on the board schematics -- page 40 of the SUPER_ELF.pdf I referenced earlier, rotate counter-clockwise and it's in the top left, like in the video.)
zenith parsec that’s what I was thinking; the gray cable is the video output. Was initially looking for a RCA plug.
Gad my memory is going. I was sure there was an RCA socket, but none of what I find with a Google image search is jogging my memory. The gray cable is a fair be though. The wires up at the big cap are surly the power connection. BTW, the power supply was not a switching supply and it was massive. Laptop users should kneel down in things to the god of tech for switching power supplies.