Recent content by Melkhior

Absolutely. The '040 had a lot of improvement over the '030, including the caches and faster/better bus interface. The computational part was also a bit refined over a clock-doubled '030, as mentioned in the extract I posted. Unfortunately, most of Motorola's academic communication on the...

Mmmm, Wikipedia insists that my memory has failed me and it was 3x33 and 2x50, but no 4x. And Wikipedia happens to be correct - though it's too late to fix my post. Here's the evidence from the '486 DX4 datasheet: I guess it was the 25 and 33 MHz motherboard that were shared; as I mentioned...

It can do both, the fastest ones (DX4-100) could do either 25x4 or 33x3. They usually ended up doing 25x4 because same chip, same marketing, cheaper board, and you could do 25x3 with the slower variant (DX4-75) on the same motherboard. You wanted them to do 3x at nominal speed as that meant a...

Not really a scam. Marketing needs and all-around misunderstanding of how CPU works I'd say. WayWayTL;DR: That, and see the last few paragraphs, after all the long historical and near-technical ramblings. It's the same issue as the whole "that's an 8-bits computer and that's a 16-bits computer...

There was support added, as documented in "Designing PCI Cards and Drivers for Power Macintosh Computers" (p513). However, I have never seen the relevant status/control codes called on any 68K version of the system I've tried :-( Similar to X11; the Mac is much more simple - an application can...

"True" hardware cursor, in the style of Brooktree, don't rely on a blitter - do you use what I would describe as an "offscreen cursor" ? (stored in additional VRAM beyond the picture, perhaps alongside a copy of the area it replaces?) In the Brooktree style, the cursor bitmap is stored directly...

Indeed there is no support for hardware cursor in 6/7/8. I also have the hardware cursor (albeit smaller at IIRC 32x32, a clone of what available in Brooktree DACs in SPARCstations, also with a limited number of colors) but it's only useful in X11. At that size, if the sprite is full-color (same...

I think it's the issue is skills for now - having people involved that know how to do all the steps "after" HDL design - DFT, verification, etc., all the way to the packaging and package testing. Even when some of those steps are done by a professional house, you still need knowledgeable people...

Yes, FPGA feels a lot more like hardware than software emulation. And things like PiStorm and other feel a bit off to me - when going SW, might as well go into it fully like QEmu or MAME. I am in the semiconductor industry as well, on the design side - waiting for a chip back from TSMC at the...

Hehe, me too. Much more fun to be able to fix/update/improve/extend the design even after the hardware is done :-) Neat. Is it purely for your own stuff or di you open-source it ? My design is less efficient - it's essentially a CPU-less soft-SoC using Litex, with a bridge from the original bus...

Dedicated chip(s) for video and/or acceleration, or are you using a FPGA for everything ? The rendering show quite a small chips for a FPGA (... but then I went a bit overkill :-) I could probably get two Full HD output if I really wanted to... ). @zigzagjoe has a SE.30 video board with a...

One document that can be enlightening is the "Guide to the Macintosh® Family Hardware, Second Edition", which is available from vintageapple.com ; it describes a lot of the pre-'040 hardware. Alongside it is "Designing Cards and Drivers for the Macintosh Family, 3rd Edition"; with both of them...

Probably, but beware the behavior of MLCC capacitors. Voltage derating with DC bias can be really bad. Here's a cheap 50V, 100nF 0805 datasheet (JLCPCB 'basic' so great for cheap projects!): https://yageogroup.com/products/Capacitors/part/CC0805KRX7R9BB104 Select "Capacitance change vs. voltage...

Mmm, never looked at the serial port in details. But AFAIK, if you're lucky, they will all be in the same place in the memory space - they are all going to be the same hardware in any cases (or at least SW-compatible as they might have reimplemented some of the Z80C30 in their homegrown chip)...

Even limiting yourself to '040-based system, video can't be reliably determined, as Macs are perfectly fine when not using the onboard video (which is model-dependent) but a NuBus or PDS card instead. E.g., my Quadra 650 is perfectly happy with no internal video connected and my custom...