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Vintage Computers Any vintage computer systems, calculators, video games etc., but with an emphasis on 1980s and earlier equipment. |
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28th Apr 2021, 10:05 am | #1 |
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Cosmac CDP1802
Another of my old treasures has surfaced.
This is a pretty unusual processor as its CMOS, most processors of the era were NMOS. https://en.wikipedia.org/wiki/RCA_1802 None of the micros built up have yet re-surfaced (if indeed I kept them) The reason CMOS was important at the time was radiation, CMOS can take lots of it NMOS not so much so pretty handy for say a battlefield tactical communications system where nukes might be employed. It was also used in space probes due to its low power consumption and again I would guess its radiation resistance. Not intending to do anything with this at present time just a curiosity for now Some pics of some of the other items with it (there were at least 30 various processors + support chips and proms in the plastic drawer) There's an 8080, Fairchild F8, 1702 Eprom, 5203 Eprom Cheers Mike T
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28th Apr 2021, 10:23 am | #2 |
Heptode
Join Date: Jun 2019
Location: Oxfordshire
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Re: Cosmac CDP1802
The really rad hard ones were made in Silicon-on-Sapphire (SOS) as that didn't latch up like ordinary CMOS. And they cost a small fortune.
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28th Apr 2021, 10:27 am | #3 |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
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Re: Cosmac CDP1802
Believe it or not, there are people who collect old chips like those EPROMs - not to use, but just for their aesthetic appeal / appearance, much like collecting stamps or beermats.
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28th Apr 2021, 10:28 am | #4 |
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Re: Cosmac CDP1802
Nothing was too good for our boys their radios would still work while they fried
I first met this beastie in late 1976 the processor replaced a discrete CMOS processor using ALU's and half a dozen support IC's. Cheers Mike T
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28th Apr 2021, 10:30 am | #5 | |
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Re: Cosmac CDP1802
Quote:
As they come from my first full time job after college they are more than just collectables to me. Cheers Mike T
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28th Apr 2021, 12:35 pm | #6 |
Dekatron
Join Date: Jun 2015
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Re: Cosmac CDP1802
The early-ish Microwriters (text entry/storage units with a chording keyboard) used the 1802 I think. Certainly the MW4 did, I've just looked at the circuit diagram. I guess the low power consumption of the CMOS device was useful here.
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28th Apr 2021, 3:19 pm | #7 |
Dekatron
Join Date: Apr 2012
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Re: Cosmac CDP1802
I used the 1802 in the first piece of 'professional' microprocessor-based equipment I ever designed [for data-collection on highly bio-secure pig-breeding farms]. Its big attraction was its low power-consumption when compared to other microprocessors of the same era, meaning the whole thing could be built into a hermetically-sealed [IP67] immersion/UV-light-sterilisation/jet-wash-with-disinfectant-proof box and the [Mercury!] batteries would last for a year of typical use.
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28th Apr 2021, 4:09 pm | #8 |
Triode
Join Date: Feb 2021
Location: Kingston upon Thames, Greater London, UK.
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Re: Cosmac CDP1802
That's the first microprocessor I ever programmed, via switches on a homebrew COSMAC elf built by my physics teacher!
I see your location... I was a regular visitor to the Exeter and District Amateur Computer Club at the time... used to meet in the University Chemistry department... wow that was a long time ago! |
28th Apr 2021, 5:28 pm | #9 |
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Re: Cosmac CDP1802
Hi Andrew
It was a small crowd so we would have certainly met. I had moved on to Z80's and 6502's by then It was pretty active as I recall! I usually attended with one or more of the Xtal Research Guys Work commitments meant I didn't attend as often as I wanted to. Cheers Mike T
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28th Apr 2021, 8:48 pm | #10 |
Octode
Join Date: May 2018
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Re: Cosmac CDP1802
Apparently the 1802 was the only processor that was simple enough to have its circuitry 100% formally-verified for correct operation. So presumably didn't have any undocumented instructions that didn't work, and meant it was approved for space etc. applications.
However, they were very nice to program by all accounts - But maybe not much worse compared to some other oddities at the time like the F8 or even early PIC's. IIRC, Philips also used one in an old Pager-Programmer interface, I've got. Yes, White ceramic 'pre-production' / Industrial-spec CPU's are quite desirable. So when a friend found a 6502 in something, he swapped it for a standard plastic one and got £100 for the ceramic IC. Not sure if, just like the old computers, the 'stock market bubble' will eventually burst in the future, and it's best to cash in before then and but them back again later. Or whether these have all been through the large first and only crash in prices already. |
28th Apr 2021, 8:49 pm | #11 |
Pentode
Join Date: Jun 2012
Location: Bristol, UK.
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Re: Cosmac CDP1802
As well as voyaging to Jupiter in the Galileo spacecraft, the 1802 was processor of choice for early 'micromouse' builders because of the low power requirements. These 'mice' are miniature maze-solving robots competing to navigate a new labyrinth in the fastest time.
Competitions continue to this day. |
28th Apr 2021, 9:32 pm | #12 |
Heptode
Join Date: Mar 2009
Location: Portsmouth, Hampshire, UK.
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Re: Cosmac CDP1802
Another radio from Plessey Westleigh that used the 1802.
Jim |
28th Apr 2021, 9:52 pm | #13 |
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Re: Cosmac CDP1802
Nice one Jim
Yes I am not surprised Plessey like to use Government money to develop other products I think this one was after my time I certainly never saw any development models but it probably shares a great deal of Ptarmigans design and probably came from the same teams I left West Leigh in 1978 Looks as if the CDP1802 had a lot of uses. Cheers Mike T
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