18 years between posts? That must be some kind of record!
Yeah... :? Years ago (many years ago) I did a lot of 6502 stuff. I'm retired now, but I still do hobby projects with both old and new parts.
For "old", my fav is the DEC T-11 (I worked for DEC), and also 6800-series (such as 68701, with ...

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My KIM-1 stuff is for sale on e*ay, item 233868439598.

Pete

Just got an AIM-65 system which is packaged under the name "Cybex Data Reduction Computer". It has a plastic case that includes a power supply. The AIM board is plugged into a 'backplane' that includes 12KB of static RAM, and another board with a D/A on it. It was made in about 1983.

Pete

[ I meant to reply this to "ALL", but I couldn't find a way to do that... If someone knows how to modify this reply to be 'ALL', then please do so. ]

I recently finished my first 6800-based project. It's a vintage-style microcomputer, with the following features:
- 6800 running at 1 Mhz.
- S-100 ...

If it helps:
A surplus dealer, Fair Radio, has VIC-20 boards, which include an original NMOS 6502A, and two NMOS 6522's, and the VIC chip, etc. I bought several of these boards a few years ago, and most were functional. Most had the major chips in sockets - a couple had them soldered in, I think ...

I recently got things working on this project:
- It implements 18 'words' so far, including a do-while loop.
- It's mounted in a briefcase, with a battery, etc., so I can sit it on my lap while I implement more 'words'.
- One thing I changed related to earlier discussion: I'm not storing a length ...

To elaborate a little on what I said in .2:
In the VIC-20, and probably lots of similar machines, the video chip is really a CPU of sorts, and it generates the timing used by the real CPU. On alternate half-cycles, the VIC chip and the 6502 access the same RAM (namely the video memory). Tri-state ...

I think your statements in .1 are all correct (Garth may need to correct me...).
You may get some hints by looking at the schematics for something like a VIC-20 - the "VIC chip" shares RAM with the 6502 in a way similar to what you describe.

One cool feature of the original 6800 CPU was that it has ...

I don't have all the C64 details at hand, but here are some guidelines:

- Programs load into RAM, not ROM. ROM is "Read Only", so whatever the C64 has in ROM is 'static'.
- If a C64 is running from a plug-in cartridge, then that cartridge consists of additional ROM.
- If the program is in BASIC ...

Here's a whacky idea:
Get an old 386, 486, or slow Pentium PC box - anything that supports the video card you want to use (maybe an old laptop?).
Connect your 6502 SBC to the PC via the serial or parallel port.
Write SW on the PC to process "requests" from the SBC to update the video. Note that you ...

I think I agree with pretty much everything you said in .7.
You make a good point about the value of indirect addressing as an alternative (superior?) to a 16-bit index register.

Perhaps one convenience of the 6800 is that you could also store 2-byte vectors in RAM; then when you need to increment ...

I did a little checking this morning.

First let me start by saying that I'm looking at the original 6502 vs the original 6800. It's safe to say that in later generations of both, the features improved quickly. As I mentioned before, I have a 'historical' interest in this stuff, not necessarily a ...

As you pointed out right up front, it's easier to compare the modern versions of each... I agree, but then I must point out that many of your counter-points are 6800 vs 65816, not 68HCxxx vs 65816.
I think of the 6502 and 6800 as 'historic', and I was comparing them as such. I'll do a more detailed ...

...And I forgot to mention that the 6800 has 2 8-bit accumulators, which makes up for having only one index register (although it's 16-bit - yay!). The follow-on CPUs to the 6800, such as the 6803, added instructions for combining the two accumulators into a single 16-bit accumulator, thus allowing ...

I've recently gotten interested in the 6800 processor. Has anyone ever used one in a project?

I haven't used one yet, but from reading the books, I see several nice features:
- Tri-state address bus. With a 6502, to do any sort of "DMA" activity, you'll have to use separate tri-state buffers, since ...