4 ms·

OK folks, here it is, the IEEE Spectrum article where Bill Mensch says, directly, that the 6502 was intended to compete with the Intel 4040 for low-cost embedde

OK folks, here it is, the IEEE Spectrum article where Bill Mensch says, directly, that the 6502 was intended to compete with the Intel 4040 for low-cost embedded applications and says, again directly, that it was not intended to compete with the 8080 and 6800.

rasz 3y ago
>not intended to compete with the 8080 and 6800 Clearly, as evidenced by 6501 drop in pin compatibility followed by Motorola lawsuit settled for $200K and pin configuration change.
- systems_glitch 3y ago
  Supposedly the drop-in compatibility was so they didn't have to also design a development board right out the gate. I don't know what one could want for a more direct, firsthand account of what it was or wasn't designed to compete with -- Bill Mensch is the guy who did the silicon tape-up for the thing!
klelatti 3y ago
Thanks for sharing this - it's a great interview. I do think there is a subtlety about the 'wasn't intended to compete with the 6800' line though. Chuck Peddle recognised the market for a much cheaper version of the 6800 which Motorola refused to make, possibly because they couldn't make it that cheaply with the contact lithography process they were using. So Peddle went off to MOS Technology (taking lots of Motorola engineers with him including Mensch) to make the cheaper version. To achieve that goal, they had to cut down on some of the 6800's features. Reducing the size of the stack pointer, only one accumulator, and so on. As it turns out, the end result - the 6501/2 - was actually very competitive with the 6800. So whilst the original intention wasn't to compete with the 6800, in the end it did compete with it very successfully in some important markets. Of course, in addition MOS Technology didn't have the resources of Motorola and so also couldn't compete with them in terms of support, peripherals and so on. Note: I wrote the original post on the 6800 that led to the discussion [1] and I'm now deep in the writing of Part 2 of the 6800 story. (So I've now provided spoilers for Part 2!) [1] https://news.ycombinator.com/item?id=38616591 https://news.ycombinator.com/item?id=38616591
- systems_glitch 3y ago
  The 6502 absolutely did evolve to compete (and overtake, in some fields) the 6800, no doubt about it! The motivation of competing on the embedded market (whether you see that in Bill Mensch's IEEE interview quote, or Chuck Peddle's lamenting that customers didn't like the $300 tag on the 6800) explains a lot of the design choices though, especially when considering support chips like the 6530 mask-programmed RRIOT. Thanks for a great 6800 writeup, and I look forward to the follow-up! I feel like the 6800 does not get the love it deserves from the current generation of hackers.
  - klelatti 3y ago
    Thanks so much! There is so much to cover in Part 2 so it might take a little while. Completely agree that the 6800 needs more love. It was a really important design. PS I'd not seen Mensch's comment that Peddle's intention was to raid Motorola for engineers before - that's an interesting angle!!
    - systems_glitch 3y ago
      Yeah I'm sure the corporate raid had something to do with Motorola dropping the hammer on them over the 6501 pinout. Bill Mensch has said really it was just so they didn't need to design a development system right out the gate, and that they figured other engineers would appreciate that. Seems like it alone wouldn't have been enough to get Motorola mad, especially since they must've known they were just bogging MOS down, and that the pinout wasn't legally defensible reasoning to stop production (MOS and second sources later continued with the 6512, which is effectively 6800 pinout with very, very minor changes).
- RetroTechie 3y ago
  > As it turns out, the end result - the 6501/2 - was actually very competitive with the 6800. So whilst the original intention wasn't to compete with the 6800, in the end it did compete with it very successfully in some important markets. Another subtlety: the ecosystem. Obviously a cheaper cpu encourages usage in more places. Read: more users & more designers working with it. Over time, that means more tools (including better ones), more OSes to run on it, more application software, more code examples, more existing systems that can be used to kick-start a new design, more knowledge in the field to work around quirks, etc. Often that ecosystem weighs heavier than cpu features, price or performance. Yeah a 'nicer' cpu will drop in price. But by then it's late to the party.

rasz 3y ago

>not intended to compete with the 8080 and 6800 Clearly, as evidenced by 6501 drop in pin compatibility followed by Motorola lawsuit settled for $200K and pin configuration change.

systems_glitch 3y ago
Supposedly the drop-in compatibility was so they didn't have to also design a development board right out the gate. I don't know what one could want for a more direct, firsthand account of what it was or wasn't designed to compete with -- Bill Mensch is the guy who did the silicon tape-up for the thing!

klelatti 3y ago

Thanks for sharing this - it's a great interview. I do think there is a subtlety about the 'wasn't intended to compete with the 6800' line though. Chuck Peddle recognised the market for a much cheaper version of the 6800 which Motorola refused to make, possibly because they couldn't make it that cheaply with the contact lithography process they were using. So Peddle went off to MOS Technology (taking lots of Motorola engineers with him including Mensch) to make the cheaper version. To achieve that goal, they had to cut down on some of the 6800's features. Reducing the size of the stack pointer, only one accumulator, and so on. As it turns out, the end result - the 6501/2 - was actually very competitive with the 6800. So whilst the original intention wasn't to compete with the 6800, in the end it did compete with it very successfully in some important markets. Of course, in addition MOS Technology didn't have the resources of Motorola and so also couldn't compete with them in terms of support, peripherals and so on. Note: I wrote the original post on the 6800 that led to the discussion [1] and I'm now deep in the writing of Part 2 of the 6800 story. (So I've now provided spoilers for Part 2!) [1] https://news.ycombinator.com/item?id=38616591 https://news.ycombinator.com/item?id=38616591

systems_glitch 3y ago
The 6502 absolutely did evolve to compete (and overtake, in some fields) the 6800, no doubt about it! The motivation of competing on the embedded market (whether you see that in Bill Mensch's IEEE interview quote, or Chuck Peddle's lamenting that customers didn't like the $300 tag on the 6800) explains a lot of the design choices though, especially when considering support chips like the 6530 mask-programmed RRIOT. Thanks for a great 6800 writeup, and I look forward to the follow-up! I feel like the 6800 does not get the love it deserves from the current generation of hackers.
- klelatti 3y ago
  Thanks so much! There is so much to cover in Part 2 so it might take a little while. Completely agree that the 6800 needs more love. It was a really important design. PS I'd not seen Mensch's comment that Peddle's intention was to raid Motorola for engineers before - that's an interesting angle!!
  - systems_glitch 3y ago
    Yeah I'm sure the corporate raid had something to do with Motorola dropping the hammer on them over the 6501 pinout. Bill Mensch has said really it was just so they didn't need to design a development system right out the gate, and that they figured other engineers would appreciate that. Seems like it alone wouldn't have been enough to get Motorola mad, especially since they must've known they were just bogging MOS down, and that the pinout wasn't legally defensible reasoning to stop production (MOS and second sources later continued with the 6512, which is effectively 6800 pinout with very, very minor changes).
RetroTechie 3y ago
> As it turns out, the end result - the 6501/2 - was actually very competitive with the 6800. So whilst the original intention wasn't to compete with the 6800, in the end it did compete with it very successfully in some important markets. Another subtlety: the ecosystem. Obviously a cheaper cpu encourages usage in more places. Read: more users & more designers working with it. Over time, that means more tools (including better ones), more OSes to run on it, more application software, more code examples, more existing systems that can be used to kick-start a new design, more knowledge in the field to work around quirks, etc. Often that ecosystem weighs heavier than cpu features, price or performance. Yeah a 'nicer' cpu will drop in price. But by then it's late to the party.