Quest SuperElf: an early personal computer - Page 1
Forum section: electronics / general

author: electronupdate
author_rank: Regular Contributor
timestamp: June 20, 2020, 11:58:05 am
content: I dusted off my very first computer and powered it back up.... still works great after 43 years. A video on what hobbyist computing looked like in mid 1970's.There was lots of variety of CPU chips back then. This one used the 1802 which was fairly unique. No dedicated program counter (any one of 16 general purpose registers could be configured to be the counter on the fly), no pop-push instructions (i.e. no stack). Dedicated instructions for setting a pin.https://youtu.be/eH8RhX2Veog

author: jfiresto
author_rank: Frequent Contributor
timestamp: June 20, 2020, 06:26:11 pm
content: The 1802 may not have an explicit stack pointer, but any one of the other sixteen registers that is not being used as the program counter can serve – or that perhaps is being used.You just set X(SEX)to the register pointing to your stack (or one of your stacks) and off you go.You can then pop withLDXAand push withSTXD, and all the logic and arithmetic instructions can use the X-pointed-to-register (i.e., your stack), to provide an operand. The 1802's solitary, hideous wart, IMHO, was that STore via X and Decrement(STXD)should have beenDSTX.I use present tense because the 1802 is still being made.EDIT: I liked your video. It rekindles the spirit of programming the simple machines from back then.

author: floobydust
author_rank: Super Contributor
timestamp: June 21, 2020, 09:22:21 pm
content: How do you program it without an address displayIt's missing the DM9368 IC's, FND500 LED displays and extra voltage regulator for them. I still have my Quest SuperElf but could not afford the enclosure, so it's just a bare board.Video output was super cool. I have the books for it somewhere.

author: jfiresto
author_rank: Frequent Contributor
timestamp: June 22, 2020, 10:50:39 am
content: Quote from: floobydust on June 21, 2020, 09:22:21 pmI think for most that was not a great issue. What I wondered about were the folks who keyed in their programs in binary using toggle switches. They knew and felt each bit, intimately.

author: floobydust
author_rank: Super Contributor
timestamp: June 23, 2020, 01:25:26 am
content: Toggle switch computers have LEDs showing the address- so you could step through and examine memory. Because one byte entered wrong would usually scramble an entire program and you would have to re-enter it, which was no fun at all.pic taken fromhttps://skrolli.fi/2016/06/40-vuotta-altair-8800-mikrotietokoneajan-airut/

author: rrinker
author_rank: Super Contributor
timestamp: June 23, 2020, 06:29:38 pm
content: Also my first computer. When I first bought it, I did save up enough to get the high and low address display options with the main unit (why the high address on a computer with only 256 BYTES of RAM, I'm not sure...). The following year I got the Super Expansion board with 4K and all the options, and the metal case. Still have it all, still works. I was planning to fully expand it, so I even have the big monster power supply that goes in the case, complete with massive transformer and giant beer can Sprague capacitor. Things were changing rapidly in those days and I pretty much moved on before I added all the real goodies like the color video board, a keyboard, or more memory to run BASIC.There's still an active group, was on Yahoo, now on groups.io where not only are the old machines talked about (Netronics and their Elf II was another contemporary - I can remember poring over the ads in Popular Electronics comparing features to determine which one I wanted to get. Sent away for catalogs - wish I still had the Quest catalog. After much agonizing and writing down a comparison chart (which I found stuffed in one of the manuals), I decided on the Super Elf. Saved up my grass cutting money (I was only 13) and had my Mom send away a check. Not like Amazon today - it was at least a week across the US, PA to CA, and then 6 weeks to wait for the check too clear, then another 2 weeks or so shipping. Carefully put it together and - it didn't work. I don't recall exactly where I had gone wrong, but I think I had some bad logic bits - luckily in those days there was an RCA dealer across from the library we frequented who stocked many of the common 4000 series logic.Quest had their own user newsletter , when I bought the computer, or maybe when I bought the expansion, I got the bound edition of the first volume, which had a lot of learning articles. Eventually I came up with couple of ideas, one a light pen I built with a CdS cell and the guts of the old Radio Shack pocket microscope (looked like a fat pen). I typed up both these articles, on an old manual typewriter, and sent them in. Never heard anything. A few years ago, I came across this 1802 group on Yahoo and immediately joined. They have lots of reference material, including scanned copies of all the newsletters. Imagine my surprise when I opened one of them and there was my article I sent in! Published author at 13!Another thing I did was modify a portable TV I had for a video display. I bought an RF modulator kit they sold with the computer, but could never get it to work. No matter what, never saw anything close to what was supposed to be displayed. So on a whim, I opened up the TV I was using, and when I looked at it, I thought, there's no way it can be this easy. But it was. The tuner board was on one side of the bottom, and on the other side was the video driver - and they were connected by a coax cable with RCA plugs on each end. I disconnected it, and with some trepidation, attached the video out from my computer to the supposed video in on the TV - and it worked! Nothing blew up. So I made it 'fancy' with a simple SPDT toggle and an extra RCA socket - one way connected the tuner board, the other connected the socket, where I plugged in the computer. A pretty dodgy setup - the socket I got wasn't panel mount, so it just hung out the back of the TV case. I did drill a hole and attach the toggle switch.Sheesh - memories of an old man. That was all nearly 40 years ago.

author: floobydust
author_rank: Super Contributor
timestamp: June 24, 2020, 03:05:10 am
content: This thing was expensive! $USD 116 is $431 today plus shipping, taxes and customs/exchange. No wonder I was broke. Computers were a massive money pit back then.Tiny BASIC existed for it, $10 on cassette ($35 today) and $38 ROM ($134 in today's dollars).Super BASIC came out Oct. 1979 but $40 on cassette ($141) for 12KB OUCH.It (Super Elf) climaxed after a year, in 1980 and then fizzled out in 1981, a loser in the personal computer microprocessor wars.The Q-port was kinda neat, I hooked up an SPO256 and had it talking. But assembler was a bit tough for a kid to figure out. I have the RF modulator and the on-screen clock and Star Trek Enterprise program. Someday I'll put that in an EPROM lol.

author: rrinker
author_rank: Super Contributor
timestamp: June 24, 2020, 09:30:17 pm
content: I sort of had it figured out before I bought the computer. The first thing that turned me on to the 1802 was actually a Radio-Electronics article on the predecessor 1801 MicroTutor. I think the issue was from 1976, but I picked it up around 1978. It went over both the hardware and many of the opcodes - I rear that article over and over again until i understood it. 1802's machine language is well organized and pretty easy to pick up.I had a lot of 'dream' systems picked out from magazine ads, but most of those were a thousand dollars or more back then. The $106 I paid for the Super Elf seemed cheap - a TRS-80 or Apple 2 was close to $1000 as well. Considering one just sold for $1280 (just the base system with the address displays!) and there is another listed for $700, and just the power supply like the one I have listed for $135 - I think I made out pretty good. I learned a lot building and operating that system, and the 1802 assembly/machine code still remains my favorite and easiest to use 8 bit assembly - I had to write an assembly routine for my BASIC program on an Apple II in high school and I absolutely cannot stand the 6502 architecture. All the C64 fanboys drive me nuts.One I do kind of want is one of those 8085 Intel boards like Dave recently did a video on. I always thought it was a neat SBC, even if Intel's instruction set aligns better with Octal than it does with Hex. But they are also going for crazy money, and no way would I get an unassembled one to just sit on a shelf, i would have to build it. I do have a TRS-80 Model 100 if I want to play with an 8085.