The 68000 was allegedly named for its (approximately) 68k transistors, and to imply some sort of relation to Motorola’s first microprocessor, the 6800.
But then how did Motorola pick the name “6800”?
asked Jun 26, 2022 at 0:09
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4Not the transistor count. It seems to have had about 4,100 transistors in its original version.– John DallmanCommented Jun 26, 2022 at 9:58
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3The whole ecosystem was called the M6800 Microcmputer System and contained a lot of chips, such as 6850 UART, 6870 clock generator, 6830 ROM, 6810 RAM and 6820 PIA. The 6800 and later 680X chips (6801, 6805, 6809) were the microprocessors or microcontrollers of the ecosystem. So everything was named after a common numbering system. But good question is where does the name and numbering system come from. An the C in the MC6800.– JustmeCommented Jun 26, 2022 at 10:16
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2@Justme I always thought "MC" stood for "Motorola Corporation".– Brian HCommented Jun 26, 2022 at 13:01
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1At a guess, it is just the next one in their product series. There is probably a product list somewhere where in Motorola HQ. 6000 and 6600 are portable radios, 6100 is a walkie-talkie, 6200 tv transmitters, 6400 is networking equipment, 6500 is a radio. It is possible that failed products have their numbers reused. 6700 is a mobile phone.– cupCommented Jun 26, 2022 at 19:30
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@BrianH Not really, if at all, MC may be read as "Motorola Component". In contrast to M alone naming a family.– RaffzahnCommented Jun 26, 2022 at 21:35
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1 Answer
Maybe not an a direct answer, but a few hints about Motorola naming conventions where preceding symbols distinguish between families, devices, implementation and technology.
Examples are:
- M6800 is the 6800 family designator, while
- MC6800 is the 6800 CPU
During the early 1970s this system was way more detailed with tons of additional letters and numbers. Including different meaning for the same symbol when it's about discrete semiconductors or integrated ones, linear or TTL.
For the purpose of microprocessors it's simply M* when it's about a generic/family like when talking about the M6800-Bus or the M6805 I/O and MC* when it's about a specific device like the MC6802 controller (*1). The rest (*2) can be usually ignored. A notable exception was the prefix `*14 for CMOS - at least when they were new
- MC146805 being a 6805 CPU in CMOS
Oh, and there's the 'M' for memories, leading to the fun addition that the 128 Byte (1 KiBit) RAM of the M6800 family isn't named MC like all other devices but MCM6810 :))
Motorola also never had a consistent scheme for the numbers to follow. Not for semiconductors and even less for the company at whole. There are in fact several unrelated duplicates. Of course this helps to integrate second sourced components, like the F8 being simply named MC3850.
On a side note, the claim about being named for its 68k transistors is more of a marketing tag added as afterthought. The 'name' was already fixed way before the they had an idea how many transistors it will be. Not to mention that it's easy to scale the value by including or not including certain types of 'transistors'.
*1 - While M is almost certainly meaning Motorola, there is no consistent meaning for C, although reading it as Semiconductor-Device usually works.
*2 - An added C (like MCC*) usually marks a chip, while the same with a W added (MCW*) is a wafer.
answered Jun 26, 2022 at 21:34
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4Reading the CHM’s 68000 Oral History right now, and they mentioned there were also about 68000 employees at Motorola at the time! Commented Jun 26, 2022 at 23:59
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1Is "waver" a typo or is it a term I should know but I'm just ignorant. Google isn't helping. I can only think of "wafer" but that doesn't make sense I think. Commented Jun 27, 2022 at 2:36
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1The MC6802 is not a microcontroller, if that's what you meant by "controller," it's just a CPU. The 6801 was a microcontroller. For your answer, a better example might be the MC6820 PIA (which might be considered an I/O "controller"), which clarifies that the "C" part was not just about CPUs or components containing CPUs.– cjsCommented Jun 27, 2022 at 6:34
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1@hippietrail Jup, it's a type, meant to spell wafer. Tell me, why wouldn't that make sense?– RaffzahnCommented Jun 27, 2022 at 9:21
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1@hippietrail Not your fault. Just imagine that a manufacturer has to track of products during production, that will of course include wafers, wouldn't it? Now, 'WAFER OF MC6800' makes a real bad item number within the inventory system tracking them, wouldn't it? Also, you're right, they also sold (like many others) wafers as whole, usually for others to integrate them in carrierless design, but as well for second source. Buying a waver is a lot cheaper, but bearing the risk of an unknown number of defects. As well a common practice.– RaffzahnCommented Jun 27, 2022 at 13:56