Anyone else ever used a 6829 MMU (meant for the 6809) with a 6502? I've just built a new board, and a preliminary test (LEDs flashing from a 6522) seems to be working


(The 6829 is the one between the EPROM and the CPU- it only says 6829 on the bottom for some reason.)

If I can see it working, I might believe you. Post a vid, otherwise: BULLOCKS! You have a datasheet on that 6829?

Edit:Sorry mate, I was in abit of a fit, not over your post though. I was in an all around bad mood.

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65Org16:https://github.com/ElEctric-EyE/verilog-6502

What exactly is the point of that comment?

Do you have some reason to believe it can't work?

If he did post a video of a board with some LEDs flashing
what would that prove?

As to the datasheet, try Google

The 6829 is real.
Datasheet
Also mentioned here.

As bogax said, flashing LEDs (one 3-pin LED with a red and a green part actually) wouldn't prove much.

Edit: I can, however, provide a schematic. Some pin numbers may differ. The actual board, as you can see, isn't finished yet- I wanted to make sure first that the SC67476 chips are actually what the eBay seller said they are. (SC means special/custom.)

Nobody said it wasn't real. I recall the 6829 from about 25 years ago, back when a 2 MHz eight bit part was a screamer.

Be that as it may, why bother with such an ancient and constricted piece of silicon? Aside from the difficulty of trying to find parts, the thing is dog-slow by today's (even yesterday's) standards and would require some fiddling to correctly interface it with a 65C02. You have to synthesize the Q clock signal, since there's no analog for it in the the 'C02 (or the MC6800—the 6829 was designed for use with the 6809). Adding insult to injury, the 6829 is an HMOS part, power-hungry and, as I said, dog-slow. Plus it's limited to four protected tasks. Why bother?

With a little more work, you can achieve much better functionality with a PLD and a little aptness of thought. When you were done, you'd have an MMU with low nanosecond prop time and no funky clock requirements. You can then run your 65C02 as fast as you want.

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x86?  We ain't got no x86.  We don't NEED no stinking x86!

The schematic is practically unreadable. Why does everyone have to use color? Old guys like me with partial color-blindness are left in the cold.

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x86?  We ain't got no x86.  We don't NEED no stinking x86!

Looks like a great project to me!

For a monochrome picture, see

It is big, so you'll have to find a way to view it full size. Any down-scaling is likely to have trouble with the single-pixel widths.

Thanks for the mono version. I imported the drawing into DeltaCad, which makes displaying and printing it fairly easy.

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x86?  We ain't got no x86.  We don't NEED no stinking x86!

Nice thing! basically an extension of my 74LS610 based MMU approach (4 -> 8 address bits, plus some special purpose bits like write protect and no-execute) -> http://www.6502.org/users/andre/csa/

I like the "task" approach. would help a lot for my multitasking operating system, but IIRC I'd need 8 tasks (which the 6829 obviously can do with stacking multiple MMUs) for the current setup.

Great work!
André

I see you are using Cadsoft's Eagle to create the schematics, right?

I know there's a lot of personal taste in it, but you can use busses to reduce the number of single traces on the schematics, and I haven't seen a named signal yet.

Email me if you have some questions I've done a lot with Eagle already (see http://www.6502.org/users/andre/csa/ )

André

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http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

I only started using Eagle fairly recently, because I wanted proper PCBs made for a couple of ROM cartridges. Before that my schematics would be scribbled on paper, or worked out in my head.

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http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

can anyone reverse the 6829 to a VHDL version for any of us dreamer types for future designs?

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"My biggest dream in life? Building black plywood Habitrails"

I'm actually finding it far more worth my time to think in terms of starting out with a PCB layout, and then creating a schematic, if needed, from that. The problem with starting with a schematic first is that your pin numbers almost never line up the way you need them to. For example, as long as you're consistent about it, D0 on the CPU needn't map to D0 on a RAM chip. Likewise with a ROM chip. Of course, when programming the ROM, you need to fudge the binary image accordingly. But, if you can do that, you may find a drastic reduction in the number of vias needed to hook everything up in an otherwise "sane" design, and might even reduce the need for multiple layers all-together (which results in enormous savings).