51–60 of 127 posts
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Well, it was the predecessor :)
There was the 6809 in between. I remember BYTE magazine's cover story, "A Microprocessor for the Revolution". Well, not quite, as it turned out! :)
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> "Test condition, decrement, and branch". All in one instruction The Z80 had that too - DJNZ (Decrement and Jump if Not Zero). Standard way of writing loops.
The 8080 lacked this, but even though the 8086 was more or less based on the 8080, this probably inspired the 8086 LOOPNZ instruction. Same idea, hardcoded to use the CX register instead of B on the Z80. The unoffical nicknames for the AX, BX, CX, DX were accumulator, base, count, and data. CX was used for the count for all looping and string move instructions. Similarly, BX was special purpose for indirect operation…
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$200k sounds like such a small number, but it was the dropping of the offending chip that was the gotcha.
Well...200k in 1975 $'s. And MOS was a startup, basically. So not a trivial amount. But yeah, a big part of the initial pitch was "you can use your same hardware design but replace the $300 CPU with our $25 CPU".
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At our company we still use a MC68HC11 for an industrial device.
Be careful -- they're rapidly going obsolete. No one wants to fab old EPROM processes, and no one wants to package PLCCs anymore. If it's neither of those, I think you've got a bit more time. There are "compatibles" out there, and some of them are very good indeed, but they're not without their hassles.
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Well, it was the predecessor :)
There was the 6809 in between. I remember BYTE magazine's cover story, "A Microprocessor for the Revolution". Well, not quite, as it turned out! :)
OS-9 has an interesting history in its own right. It was ported to a wide range of subsequent architectures. All sorts of applications - Fairlight synths, Philips CD-i, most of the traffic lights in the US in the 80s and 90s to name a few.
With the optics of _compiled_ code, how do the various 8-bitters stack up? (6809/6811, 65C02, Z80, H8, ...)? One would have to account for the frequency allowed by the ISA at iso-technologies (which makes including AVR somewhat tricky). I only have experience with Z80 and 65C02 and I believe the consensus is that a 4 MHz Z80 beats a 2 MHz 65C02, but neither is a particularly nice compiler target.
IMO the Z80 is a lot nicer compiler target than the 6502, because the stack pointer is 16-bit and it's much easier to use the stack in general.
There are a couple C compilers for 6502 (like cc65 and WDC's C compiler) but they're not quite as good as SDCC, as far as I can tell. They're also not as actively maintained.
Serious question, why is this on Hacker News? is it a classic of some sort?
The 6800 definitely is a classic, yes. The classics included at least 6800, 6502, 8080, and Z80. (To some extent 8085, but as an "expanded" 8080 the Z80 dominated.) The four of them powered the most iconic systems at the start of the microprocessor "takeover" at the end of the seventies (at the same time as I entered my electronics education). The 6800 was kind of left behind by the others eventually, but was used in…
I built a small multitasking kernel with a friend with a 68000 (m68000) in college. We implemented it on breadboards, I think with 30 or so feet of jumpers [0]. I had very little prior embedded experience, so it was trial by fire. It was a wonderful introduction to how kernels work (or at least concurrency and scheduling) at their most basic level, without having to deal with the complexity of virtual address spaces,…
> [0] - https://i.imgur.com/MKD7wTv.jpg
Based on your description, I expected to see a picture of 30 feet of breadboards filled with jumpers (https://en.wikipedia.org/wiki/Jumper_(computing)), maybe used as ROM or something. Your actual project was unfortunately much less ridiculous.
With the optics of _compiled_ code, how do the various 8-bitters stack up? (6809/6811, 65C02, Z80, H8, ...)? One would have to account for the frequency allowed by the ISA at iso-technologies (which makes including AVR somewhat tricky). I only have experience with Z80 and 65C02 and I believe the consensus is that a 4 MHz Z80 beats a 2 MHz 65C02, but neither is a particularly nice compiler target.
Some of that can be gleaned from this benchmark, published in Byte, in 1981: https://en.wikipedia.org/wiki/Byte_Sieve Results for a few 8/16 bit processors are here (and on subsequent pages): https://archive.org/details/byte-magazine-1981-09/page/n193/...
21.4 seconds 5793 bytes
Which is middle of thepack for the Z80 benchmarks, but well below the 6502 ones. We're also using a slightly tweaked embedded printf written in C, so this could probably be improved somewhat there, sans any compiler changes.
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There was the 6809 in between. I remember BYTE magazine's cover story, "A Microprocessor for the Revolution". Well, not quite, as it turned out! :)
I never got to use the 6800, but did use both the 6809 and 68000 in assembler. Both were a joy to work with.
The 68000 is really a different class of CPU entirely, so I'm not sure why folks are discussing it here. Only the name is similar.
