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Yeah - but the Z80 was a clear winner over the 8080, because it only needed +5V instead of +5, -5, and +12V. 
I mostly used the Z180 / HD64180 versions, because they had the onboard MMU and USARTS, so could access 1MB (not that I had that much) and two serial ports directly. Happy days!
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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For the 40th birthday of the CDP1802 this year I'm building a slightly more powerful version. Up to nine CDP1802BCE at 5 MHz (Really good for a CPU from 1976 at 5V, there were even versions with 6.4 MHz at 10V). Also, I already have worked out a 4 mb memory board, of which it can have four for a total of 16 mb. 
The language is JavaScript. that of Mordor, which I will not utter here
This is Javascript. If you put big wheels and a racing stripe on a golf cart, it's still a f***ing golf cart.
"I don't know, extraterrestrial?"
"You mean like from space?"
"No, from Canada."
If software development were a circus, we would all be the clowns.
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Parallel processing, or multi threaded tasking?
What are you planning on doing with it (because that's going to take a while to program!)
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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9 separate processors, 1 'master' and eight 'workers'. Some will be dedicated to a specific task, like giving the graphics chip (probably going to be a MC6847) something to do. The master uploads graphics data and commands, the worker executes them.
I already have a nice stack of graphics routines for my old computer. Also, there are places where I can get great stuff from other projects, like ATA interfaces, the driver routines to control it and even a OS with a proper file system. from the old days we also have programming languages like FORTH. FORTH is great for self built computers because it doubles as OS.
And from there? perhaps a GUI? I do want to add PS/2 connectors for mouse and keyboard.
The language is JavaScript. that of Mordor, which I will not utter here
This is Javascript. If you put big wheels and a racing stripe on a golf cart, it's still a f***ing golf cart.
"I don't know, extraterrestrial?"
"You mean like from space?"
"No, from Canada."
If software development were a circus, we would all be the clowns.
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That's a lot of work! I'm seriously impressed - worth an article (or more likely a series) at the end?
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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Would there be much interest? It's not unlike today's projects with the Raspberry Pi or Arduino. Everything is slightly bigger and perhaps a little slower, but the problems and their solutions are almost the same.
I spent the last week with digging out routines for bit banging a simple RS232 interface. I will need them for the master processor prototype. It will not have any I/O yet, so a RS232 and an old notebook with terminal emulation will help a lot.
The old routines were for (even then) very conservative 300 baud. I already have modified them up to 1200 baud. The emulator does not give any plausible results for higher clock frequencies, but there are people who claim to have reached 4800 baud at 2 MHz. 9600 baud could be within reach at 5 MHz.
The language is JavaScript. that of Mordor, which I will not utter here
This is Javascript. If you put big wheels and a racing stripe on a golf cart, it's still a f***ing golf cart.
"I don't know, extraterrestrial?"
"You mean like from space?"
"No, from Canada."
If software development were a circus, we would all be the clowns.
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Maybe among people who understand this stuff: the "new kids on the block" don't seem to realise that all of this stuff is still there, deep down, hidden where they can't see it to "protect them" from having to work with more basic structures than a List of references to objects. Heck, some of them work with serial ports and can't understand why a short message might take several seconds to be transferred. 
And it would be a pity to let that knowledge slip silently into the night...
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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Not all is lost. There are still some who build an Elf[^] or one of its descendants.[^]
By the way: My new version is not going to be named 'Elf'. We already had so many variations, like Elf II, Super Elf or Elf 2k. I think I'm going to call it 'Zwölf'.
The language is JavaScript. that of Mordor, which I will not utter here
This is Javascript. If you put big wheels and a racing stripe on a golf cart, it's still a f***ing golf cart.
"I don't know, extraterrestrial?"
"You mean like from space?"
"No, from Canada."
If software development were a circus, we would all be the clowns.
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Why "12"?
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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Elf = Pointy eared tree hugger, shoots arrows when angry.
It's also the German word for eleven.
We have been saying that for a long time already, especially in connection with a pointy eared character from the Lord of the Rings.
The language is JavaScript. that of Mordor, which I will not utter here
This is Javascript. If you put big wheels and a racing stripe on a golf cart, it's still a f***ing golf cart.
"I don't know, extraterrestrial?"
"You mean like from space?"
"No, from Canada."
If software development were a circus, we would all be the clowns.
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Ah!
My German is very basic - all courtesy of a girlfriend who worked for CERN for a few years, before she emigrated to the USA. Most of it (when I used it enough to remember it) consisted of food and beer ordering ... 
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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Elf Bier, bitte! Oder doch besser gleich zwölf? 
The language is JavaScript. that of Mordor, which I will not utter here
This is Javascript. If you put big wheels and a racing stripe on a golf cart, it's still a f***ing golf cart.
"I don't know, extraterrestrial?"
"You mean like from space?"
"No, from Canada."
If software development were a circus, we would all be the clowns.
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At Swiss prices? 
The most I ever ordered was "Vier Bier, bitte!" 
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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Right, we did not have that yet!
The language is JavaScript. that of Mordor, which I will not utter here
This is Javascript. If you put big wheels and a racing stripe on a golf cart, it's still a f***ing golf cart.
"I don't know, extraterrestrial?"
"You mean like from space?"
"No, from Canada."
If software development were a circus, we would all be the clowns.
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Whoa - that takes me back. I used to work for a company which marketed a desktop financial calculator. The number crunching was done in with an 8088 but that drew too much power to be battery powered, so the main calculator ran on an 1802 and it powered up the 8088 when it needed to do any calculating then powered it down again.
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That was the 1802's greatest strength and one of the reasons why it still exists. It it draws power in the µW to mW range and can run for months on normal batteries.
The language is JavaScript. that of Mordor, which I will not utter here
This is Javascript. If you put big wheels and a racing stripe on a golf cart, it's still a f***ing golf cart.
"I don't know, extraterrestrial?"
"You mean like from space?"
"No, from Canada."
If software development were a circus, we would all be the clowns.
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You can probably guess from the fact that an 8088 was used that this was back in the early 80's. So parts were still pricey, and to keep costs down we only used 4 bits width of 1802 memory. Which meant some unusual gymnastics in the 1802's software (which, thankfully, I didn't have to write).
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Programming the 1802 is a pleasure. It's an early RISC design, but I think you got that with the 4 bits wrong. I can't think of any usable set of instructions that used only four data bits and has the others pulled up or down to a constant value.
Could it be that it used only a 8 bit address bus? The 1802 mutiplexed its address lines and small computers (including the original Elf) omitted the latch for the upper address bits and used only the lower address bits with a 256 byte RAM. That's also why my old computer has three different latches for the upper address bits on various expansion boards.
The language is JavaScript. that of Mordor, which I will not utter here
This is Javascript. If you put big wheels and a racing stripe on a golf cart, it's still a f***ing golf cart.
"I don't know, extraterrestrial?"
"You mean like from space?"
"No, from Canada."
If software development were a circus, we would all be the clowns.
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The ROM was 8 bits wide, the RAM was definitely only 4 bits wide - it was a 2114
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That explains it then. The actual program was in the ROM and the RAM was only used to save some (obviously) 4 bit values. This may be a little awkward, but it would not be hard to do. The better question would be, wether or not the savings were worth the trouble.
The language is JavaScript. that of Mordor, which I will not utter here
This is Javascript. If you put big wheels and a racing stripe on a golf cart, it's still a f***ing golf cart.
"I don't know, extraterrestrial?"
"You mean like from space?"
"No, from Canada."
If software development were a circus, we would all be the clowns.
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Exactly so. I made one or two small changes to the code once it was in production, but didn't really get involved with the software until our next desktop calculator which was mains powered and ran completely on an 8088 (later a V20).
But I(we) digress
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Firmly on my list of things to try!
I wanna be a eunuchs developer! Pass me a bread knife!
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The old 4164 DRAM has 64 kilobits, so it must be an array of 256 x 256 bits. Not exactly high resolution, but the DRAM should be easy to get. Please don't use the ones in my old Ataris and C64s.
you did see this link?[^]
The language is JavaScript. that of Mordor, which I will not utter here
This is Javascript. If you put big wheels and a racing stripe on a golf cart, it's still a f***ing golf cart.
"I don't know, extraterrestrial?"
"You mean like from space?"
"No, from Canada."
If software development were a circus, we would all be the clowns.
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CDP1802 wrote: you did see this link?[^]
Looks like the kind of info I want -- but it also looks like it would take me a year and a half to read it!
I wanna be a eunuchs developer! Pass me a bread knife!
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