The Apple Lisa Inside an FPGA!

[joevt]

Do you have a reference for the Z8530 implementation? I know of a VHDL one in the Suska project (which I've successfully used to emulate the SCC used in a Sun-3), but it's interesting to have an alternate implementation, in particular in Verilog. But I can't find the original and the file itself doesn't include a license.

What Z8530 implementation are you referring to? The first post has a picture showing an AMD Z8530 outside of the FPGA.

 

[Melkhior]

What Z8530 implementation are you referring to? The first post has a picture showing an AMD Z8530 outside of the FPGA.

Pictures lie Quoting the GitHub readme:

Rev. 3 of the board also contains a socket for a real 8530 SCC chip for controlling the serial ports. This is because a SystemVerilog SCC core didn't exist at the time at which the board was designed. But one exists now, so the socket is empty on Rev. 3 boards and nonexistent on subsequent revisions!

The implementation is here.

 

[joevt]

Pictures lie Quoting the GitHub readme:

The implementation is here.

It looks like it's missing many SCC features. There's enough for normal asynchronous receive/transmit but not LocalTalk? LocalTalk uses FM0 instead of NRZ and it uses SDLC.

 

[shirsch]

How can I determine if I'm on the pre-order list? I *think* I remember registering but can find no way to verify that fact.

 

[AlexTheCat123]

Do you have a reference for the Z8530 implementation? I know of a VHDL one in the Suska project (which I've successfully used to emulate the SCC used in a Sun-3), but it's interesting to have an alternate implementation, in particular in Verilog. But I can't find the original and the file itself doesn't include a license.

Somebody (who I believe wishes to remain anonymous) reached out to me on LisaList2 when they heard about my predicament with the fake SCC chips and offered to help write an SCC while I worked on other aspects of getting the boards running. This is what he came up with, and it works great in all of the testing that I've done, but we didn't bother implementing much of anything outside of asynchronous transmit and receive because we figured that this was what the vast majority of Lisa users would be using. But the nice thing about FPGAs is that, if there ends up being demand for something like LocalTalk, we can always just add support, release an update, and get people to flash it to their boards!

How can I determine if I'm on the pre-order list? I *think* I remember registering but can find no way to verify that fact.

You're most likely not; everyone who was on the preorder list already responded to the emails we sent out about a week ago and purchased a board. The list you're probably thinking of is the "notify me" list, where I'll send you a notification when they go on sale to the general public here in a few days.

 

[shirsch]

Ok, thanks for the clarification. I guess I never saw a notice about the preorder list and confused the "notify me" page with it.

 

[Melkhior]

Somebody (who I believe wishes to remain anonymous) (...) and offered to help write an SCC (...) This is what he came up with

And it looks great; in particular having the option of multiple clocks. The Suska implementation is purely pclk-based, and while it does work for me in the Sun-2/Sun-3, it does require some specific relationship between the CPU clock and the baud rate, as in the original hardware - which is a pain. This SCC implementation could remove that limitation. Now to find the time to try it...

If you're still in contact with the original author, could you get them to specify a license and add that to the file? (or in jurisdiction that allows it, they can just release it to the public domain). It will make reuse easier in other projects, and I'm fairly sure a multi-clock implementation of the 8530 is something that will be reused in other projects! Also thanks to this person

Now if only we could do the same with the 8380 (SCSI) (the Temlib reimplementation of a SPARCstation 5 has the SCC, 5380 and AM7990 "Lance" Ethernet, but the original license was an issue [the author kindly relicensed his AM7990 for my Sun-3 project] and they are using a homegrown bus interface for efficiency rather than the original chip interface.).

 

[AlexTheCat123]

Yeah, the multi-clock thing is really nice here because in the Lisa, Serial A was always clocked from the 4MHz PCLK, but Serial B could be clocked from an external 3.672MHz crystal. So this allows us to perfectly simulate that!

Sure, I'll message him and see what sort of license he would like to go with. His help was a real lifesaver since I was so busy with other aspects of getting all 50 boards working! He needed an SCC implementation for a project that he was working on and so did I, so it ended up being a great deal for both of us.

 

[bmwcyclist]

GoFundMe would be a way to collect donations.