What's cool about this is that we're at the point where a committed hobbyist can pull something like this off.
I don't know what's in the FPGA, and I honestly don't know that much about FPGAs, but I imagine it's a pretty much "drag and drop" of the Lisa logic board schematic rendered in whatever FPGA language is used, while leveraging as many, stock, "off the shelf" cores as necessary.
It's telling that they externalized the UART, since they couldn't find a core to use, and weren't comfortable creating one from scratch. Otherwise it's likely a 68000 core, and a bunch of logic gates, or higher level combinatorial logic ICs (directly rendered into FPGA language, or, perhaps, they drag and dropped a, e.g. shift-register IC core).
But the point is that FPGAs are that accessible today.
Add to that the board manufacture. This is no hobbyist through hole exercise. Get the board, break out the soldering iron. No, this was built in a modern electronic assembly facility. Cheap enough to do one off boards, vs runs of 10s or 100s.
Available to the every man.
Impressive achievement for the developer, but impressive we're in a place that this is a practical thing to try and do.
> But the point is that FPGAs are that accessible today.
They've been accessible for a lot longer than most people think. The original Minimig project (an FPGA recreation of the Amiga chipset, coupled with a real 68000 CPU) started in 2005 - more than 20 years ago! And 15 years ago there was already a complete Amiga core (chipset and CPU) running on the Terasic DE1 development board, the C-One FPGA computer, and the Turbo Chameleon 64 cartridge.
Today's FPGAs are certainly more affordable and more capacious (especially in terms of DSP and RAM blocks) but the biggest shift is that, as you say, it's now possible and affordable to have the complete PCB assembled in short runs, which is a real blessing given that so many FPGAs come in BGA packages.
I really like having usable, cycle-accurate reimplementations of classic hardware (not to mention modern hardware such as RISC-V). It's the next best thing to running the real hardware, but with minimal storage space and maintenance overhead.
Cycle-accurate software emulators are great (for example people have made drop-in "hardware" CPUs [1,2] which are actually implemented in software on a microcontroller) but FPGA-based implementations are interesting not only in that they create a very realistic and usable version of the hardware, but also because an RTL implementation shows how the logic design could be implemented in hardware.
And modern FPGAs have tons of gates, more than enough to implement an entire system from the 1980s.
Xenix is the best operating system Microsoft ever shipped, but they gave up on it because there was no way they could use their PC leverage to corner the Unix market.
Interesting. I used Apple II's in elementary school (early 1980's) and then some Macs but I had never even seen a Lisa in person until going to a computer museum about 5 years ago.
It was a fascinating idea - programs were hidden behind a document template metaphor. It was not as neat as Windows “New” menu and its templates folder.
I don't know what's in the FPGA, and I honestly don't know that much about FPGAs, but I imagine it's a pretty much "drag and drop" of the Lisa logic board schematic rendered in whatever FPGA language is used, while leveraging as many, stock, "off the shelf" cores as necessary.
It's telling that they externalized the UART, since they couldn't find a core to use, and weren't comfortable creating one from scratch. Otherwise it's likely a 68000 core, and a bunch of logic gates, or higher level combinatorial logic ICs (directly rendered into FPGA language, or, perhaps, they drag and dropped a, e.g. shift-register IC core).
But the point is that FPGAs are that accessible today.
Add to that the board manufacture. This is no hobbyist through hole exercise. Get the board, break out the soldering iron. No, this was built in a modern electronic assembly facility. Cheap enough to do one off boards, vs runs of 10s or 100s.
Available to the every man.
Impressive achievement for the developer, but impressive we're in a place that this is a practical thing to try and do.
They've been accessible for a lot longer than most people think. The original Minimig project (an FPGA recreation of the Amiga chipset, coupled with a real 68000 CPU) started in 2005 - more than 20 years ago! And 15 years ago there was already a complete Amiga core (chipset and CPU) running on the Terasic DE1 development board, the C-One FPGA computer, and the Turbo Chameleon 64 cartridge.
Today's FPGAs are certainly more affordable and more capacious (especially in terms of DSP and RAM blocks) but the biggest shift is that, as you say, it's now possible and affordable to have the complete PCB assembled in short runs, which is a real blessing given that so many FPGAs come in BGA packages.
Cycle-accurate software emulators are great (for example people have made drop-in "hardware" CPUs [1,2] which are actually implemented in software on a microcontroller) but FPGA-based implementations are interesting not only in that they create a very realistic and usable version of the hardware, but also because an RTL implementation shows how the logic design could be implemented in hardware.
And modern FPGAs have tons of gates, more than enough to implement an entire system from the 1980s.
[1] https://microcorelabs.com
[2] https://eaw.app/picoz80/