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Many thanks to you for taking the time to find and share the software for those cards! Having a source code example for a video device, and in particular one using a mix of assembly and C, was very helpful to the community. In my case, when I was creating my own device and drivers.

It's only the RAM (both onboard & SIMMs) that is half-width at 16 bits in the LC. The ROM is 32-bits wide, and the PDS has access to all 32-bits of data as well. It doesn't have access to all address bits though, and that's an issue. The missing address bits (and signals for the synchronous...

No, it was certified to run at up to 40 Mhz, but it will run at whatever clock it is fed. In a Mac II, it will be fedt the 16 Mhz clock of the CPU so will run at 16 MHz. Some chips have lower ratings (much less obvious than higher!) below which they can become unreliable, but I think the...

I'm not sure why the backplane would have been a problem in 1985? It was a common approach at the time (S-100, Multibus, VME, ..). I don't remember any "pretty" computer designed with any of those, though. They were all meant for machines rooms, not living rooms like this "Jonathan" was. The...

There's OpenFPGA ongoing, and they do have some integration for Skywater. The mention of the Synopsys IC Compiler II pretty much kills the idea any hobbyist wanting to have a good look at SOFA (the license costs more than a decent house, and that's yearly; licenses costs are one of - if not the...

It's annoying, isn't it? Had that happen with the MC68060 pinouts I found on the web... and then promptly made the exact same mistake creating a footprint for the MC88110! Grrrr. Can't you just the same trick and connect the /CS output of the CPLD to an input pin of the same and use that to add...

Welcome! Congratulations, it's a very nice machine and it looks to be in excellent shape. The Wombat-based systems (so Q800, Q640, C650) are also in my opinion the best 68kMac you can get. I'm going to be a pedant (and show off my newfound knowledge), and say nope. At least two companies (Arix...

Thank you! So yes, small buffers, no termination (RCD1 to 7 are not installed), as expected - but better to be certain :-)

Probably, but only Centris 650 have LC040 IIRC - Quadra 650 and 800 have full '040. I'm trying to understand the signal termination requirements of the MC68040, and it seems Apple has done it all: I can't see any termination for A/D on the Q900 schematics, it's present but labelled "for 40 MHz...

Would you have similar pictures of the back of (one of the) board(s)? I'm checking which termination packs of resistor related to the '040 are connected, and how the output buffer are set up (resistor R17{5,6,7} and R22{1,2,3}). I do have Wombats but installed in cases will all the trimmings, if...

Diamond has a free yearly license for some chips (which is not as good as ISE / Vivado, which have free-for-life licenses for some chips), but it seems the 5-V tolerant ispMACH 4000V/Z chips use another (older?) software package, ispLEVER Classic. That used to have free yearly licenses, but no...

No, they use completely different fabs. Anything new from AMD is top-of-the line, so single-digit nanometers (MI300 is using TSMC's 5nm for instance). XC9500XL are made on a 0.35um, or 350nm, process, and I think Spartan 3 are similar. That's the kind that was used for the Pentium MMX... The...

OK thanks make sense, such a complex board with just two layers seemed unlikely. The inner-for-ground-and-power setup is fairly standard, I should have guessed. So no margin for adjustment from that (6 layers is just too freaking expensive at JLCPCB, at least for now).

I've had success with the 74CB3T family, they're used in nearly all the *FPGA (NuBus needs stronger driver so uses direction-controlled level shifters, which work well but have much longer delays than the pass-through CB3T, fine for 10 MHz but might become a problem at 33+MHz). They are not true...

Dumb question - are IIci boards only 2 layers? I can only see two colors (red/green) for traces in your original picture. That would explain the quite complex routing I see on your beautiful purple boards!

i doubt they care :-( Hobbyist are a tiny fraction of the market for ICs. Keeping old chips around may have been worth it for an independent Xilinx before the supply chains disruption from Covid, but for AMD they might be more trouble than they're worth - and now they've gotten the axe. I'm...

For those designing for 5V hardware... XC95*XL are gone. Along with Spartan II and Spartan 3, plus more. https://docs.xilinx.com/v/u/en-US/XCN23009 Darn.

Or not. Darn. (the entire range is discontinued, along with more stuff like Spartan 3).

Unique for Macintoshes, and not that common elsewhere. The 68851 was late and complex and slow and expensive, and a lot of people used other solutions, mostly custom-made MMU. For instance, Sun for the sun3 range (but sun3x were 68030), HP with some of the 300 series (at least. 9000/330 and...

Another awesome piece of work :-) Pure tracing, or is there some associated schematics? Been working on those, but it's not moving very fast... I have a bombed IIci that could use one of those replacement board, if someone could do the transplant in Europe for me (I suck at soldering anything...