The Last 8008 and 8080's?

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I am embarking on building single board computers based on the famous 8008 and 8080a microprocessors, the ancestors of the processors found in modern PC's, used in the early to mid 1970's. They are hand wire wrapped, and mounted on plaques. They have full LED alphanumeric displays describing the history of the chips. I can't believe that many more, if any, of these will ever be built. Here is my "sales pitch" for the boards:

I got the idea to start building these after seeing that people were spending well into four figures on difficult to maintain 70's computers like the Altair and Imsai that might not do anything but take up space, power, blink their LED's, and make a lot of noise. Some of them even have common 8085's or Z-80's with the original 8080 board and processor gone. Here is a newly designed and built 8080 single board computer utilizing vintage design, parts, and period hand wire-wrap prototyping techniques. The computer hardware and firmware were even designed by a period geek! It is very presentable as a piece of working technological art that you can live with.

With a whopping 2048 bytes of EPROM and 1024 bytes of RAM, the board displays its CPU, UVEPROM, and RAM tests, then scrolls a short description of the 8080 processor, utilizing vintage design "not very smart" HP medical/avionics 7x5 LED displays. The displays have no character generator or processor of their own and the 8080 must refresh them many times a second from UV-erasable read-only memory. The board uses the 8080 and real 8080 machine code to run the display - this does not use a hidden modern processor or non-vintage smart LED/LCD display technology. The highest quality gold inlaid machined pin wire wrap sockets have been utilized. A proper 8224 two phase clock chip, crystal controlled, clocks the processor (the Altair did not originally have a monolithic clock chip, which led to much grief). Processor status LED's and signals are also available via an 8212. Although many parts on the board are newer than 1980 (someone familiar can read the date codes), I believe that all components and/or technologies used in building this piece were available in the mid to late 1970's and utilized in computers of that era (for example, no green LED's, charge pumps, monolithic caps, 32K UVEPROMS, flash, etc.). This board looks and operates very much like a prototype of an 8080 based product built in the mid to late 70's would.

I have a small supply of 8080 chips, support circuitry, and displays to build these with, and each "prototype" will be unique with unique firmware and chip selections. Definitely not mass-produced (my eyesight might not last as long as my parts supply), each board takes about 12 hours to hand wire wrap and debug, and never mind the hardware/firmware design.

Each unit, serialized in UVEPROM, is mounted on a wooden plaque and comes with a UL-approved "wall wart" power supply. All have been "burned in" for 168 hours at elevated temperature. Instructions and a description of the unit are always available on the 'Net.. A custom message can be burned into UVEPROM for presentations or museums at no or a very small additional cost before shipment. Schematics, source and object code can be provided to the owner on a gold/gold CD-ROM for $5.00 additional upon signing an NDA (seriously!). Although some of the parts on the board are more than 20 years old, and these units are built as works of art and not as computing devices, I offer a limited warranty.

8080 chips of this type and condition alone are rare; a working 8080 system that does something useful is rare indeed and a great demonstration of technological history. Right now, I have boards with National gold/ceramic 8080's, Intel 8224's and Intel ceramic RAM and ROM, and even a ceramic 9080 "clone" by AMD, overclocked, of course, with fantastic selected ceramic GTE (yes, GTE) RAM and AMD eprom for AMD fans.

I got the idea to start building these after seeing people spending well into four figures on unmaintainable 70's computers that didn't do anything but take up a lot of room and power, blink their lights, and make a lot of noise. Here is a newly built (and certainly among the very last built in this century, or ever, for that matter) 8008 computer, the predecessor of the 8080 that powered the Altair and Imsai, utilizing vintage design, parts, and period wire-wrap techniques using high quality gold inlaid machined pin sockets. The computer hardware and firmware was also designed/written by a period geek! This processor was utilized in the famous "Mark-8" computer in Radio/Electronics, the Scelbi, and the early Martin Research "Mike" computers, upon which this design is based. Most of these machines are in museums, and there were darned few made and fewer still in existence. With a whopping 2K of EPROM and 256 bytes of RAM, the board displays its CPU, ROM, and RAM tests, then scrolls a short description of the 8008 processor. No matter how hard I tried I could not get "dumb" displays to refresh fast enough, so a more modern (like, 15 years old) smart red 7x5 eight- character LED display is utilized. Again, the board uses the 8008 and real 8008 machine code to perform the tests and run the display - this does not use a modern processor on the back!. Status LED's are also on board. The 8008 (compared to the 8080) was extremely difficult to get running and to interface with - the 18 pin package doesn't have all the signals to run a system and these must be recreated by external TTL logic. This is why 8008 systems involved some "voodoo" to design back then (and now...). For example, the 8008 chip has no "reset"; the reset is an interrupt to an address forced by TTL logic. Crude, but did you know that you could give the 8008 NEW instructions with external hardware?

I have a very, very small and irreplaceable supply of parts to build these with. Each "prototype" will be unique. Definitely not mass-produced, each board takes about 15 hours to hand wire wrap (and never mind the hardware/firmware design...). Because 8008 software development tools are a little hard to come by, an assembler and simulator were written from 25 year old documentation for the singular purpose of developing these boards.

Bare Intel 8008 processors in any condition, working or not, are quite rare; a working, "prototype" 8008 system with a running program is fantastically rare.

Built as art and not as a computing device, the units, serialized in UVEPROM, are mounted on nice wall plaques and come with a UL-approved "wall wart" power supply. All have been "burned in" for 168 hours at elevated temperature. Instructions and a description of the unit and how they were built are available on the 'Net. A custom message can be burned into EPROM for presentations or museums. Schematics and source code can be provided upon signing an NDA(!). Although some of the parts on the board are more than 20 years old, I offer a limited warranty.

The rear of an LC-8008 board. Keep in mind that this actually works - and there is still one production computer that comes to mind that is still wire-wrapped - the Space Shuttle's IBM computers. The reason for this is that wire-wrap is more reliable in immunity to vibration, I've been told (ordinary PCB's can crack).

Shown are a minty Tek 464 100 Mhz analog storage scope with tricked-out HP logic probe/pulser on the side with power supply, 30-year old HP logic clip, quaint HP 5326b counter/DVM (with Nixie tubes and all options), EPROM blower (I highly, highly recommend Transtronic's blower - it is inexpensive (~USD130.00), works well, and the extra cost options for burning PIC's, etc., don't cost that much extra. It can blow 32-pin EPROM's (like 4 MB chips) with no extra-cost accessories. I had looked at used burners on Ebay and they were very expensive and unsupported junk - and many of them will only blow up to 512K chips. Before you buy a "big name" EPROM blower for development, check with the manufacturer to see if it is supported at all - and if it is, how expensive it is to repair. You will be shocked. I am a cheap b_____ but I could not justify building my own and writing the UI after seeing the Transtronic.

Tektronix 1230 100 Mhz Logic Analyzer, P6444 variable-threshold pods, and training board. A lucky find, this cost over $8000 fully loaded in the late 80's /early 90's and is still very usable. I also have a spare with no probes. This particular unit has 4 probes, all wiring (some I made) and clips, serial and parallel printout (to a quaint Epson RX-80) capability. This device helped me a lot with the two-phase clocks of the 4004 and 8008.

The EPROM emulator built for this project, with only TWO chips (not counting the voltage regulator)! Beat this!! Cost to build - about USD13.00 in parts. More here.

The download software for the EPROM emulator. Callable in batch, the emulator and downloader tools are wonderful for my "burn and learn" development style.

The incredible, 3 by 2 inch dual (yes, dual) Scenix SX-28 based 8-bit bus analyzer/front panel, reconfigurable to display addresses/instructions on vintage HP 7-segment displays scanned by a Scenix (directly driven!) in hex. Compiler problems stopped me from doing the actual 8008 mnemonics. Programmable to support any 8-bit/64K addressable uP (at least the first 16K of it), this device is probably the epitome' of wire-wrap technology. It was horrible to build, and, no, neither it nor its design are for sale.

I used the quirky (but getting better), and unbeatably-priced C2C compiler, a PIC burner, the wonderful and free MPLAB, and Parallax's in-circuit debugger. Although the Parallax ICD was, and is, an absolute steal, I have seen Windows software written by casual programmers for their own use better designed and thought out. If they would make the emulator specs available, I swear I could have something better in two weeks. It is God-awful, believe me.Yet, it's worth having.

Would you believe that I have an English degree and usually do Oracle DBA work for a living? I interviewed with a company for a full-time firmware job but they couldn't believe anyone with an English degree could do this stuff. Their loss.