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Author Topic: Sun Remarketing SCSI Card Reverse-Engineering  (Read 848 times)

AlexTheCat123

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Sun Remarketing SCSI Card Reverse-Engineering
« on: February 02, 2022, 01:40:38 pm »

A few days ago, I got the idea to reverse-engineer some Lisa boards, particularly the 2/5 motherboard and the Sun SCSI card since the schematics for both of these boards are either incomplete (the motherboard) or nonexistent (the SCSI card). I want to design some replica PCBs that are as accurate to the originals as possible and release the files to everyone in the Lisa community so that it's easy and inexpensive to replace a damaged board. The motherboard is coming along really well and it's pretty easy to fill in the gaps in the schematic since I have an actual board to probe around on with the multimeter, but the SCSI card is a lot more difficult since there isn't a schematic for it and I don't actually have one of these cards, so I'm just having to follow the traces on the board around based on pictures I've found online.

It's tedious, but I've made good progress with most of the board thanks to the pictures I found on Bitsavers, the low-res but still somewhat useful picture of a blank board on the Vintagemicros site, and the pictures on this site: http://www.classic-computer-collection.de/de/neue-details/apple-lisa-2-peripherie.html. The only area of the board that I'm struggling with is the area around and underneath U4 and U6, the two logic chips right next to the 4-pin hard disk power connector. None of the pictures (other than the Vintagemicros picture, but it's way too blurry to see anything useful) show the bare board in this area and I was wondering if you guys could help me out here.

Would anybody who owns a Sun SCSI card be willing to desolder those two chips and post some pictures of that area of the board so that I can see all of the traces underneath? If not, I totally understand, but I figured that it wouldn't hurt to ask!

I'll keep you guys posted on any progress that I make with the motherboard or the SCSI card and if these projects are successful, I'm thinking about designing PCBs for the 2-port parallel card next!
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rayarachelian

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You don't know what it's like, you don't have a clue, if you did you'd find yourselves doing the same thing, too, Writing the code, Writing the code

AlexTheCat123

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Re: Sun Remarketing SCSI Card Reverse-Engineering
« Reply #2 on: February 02, 2022, 02:34:43 pm »

Thanks Ray! Those are going to be super helpful!
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patrick

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Re: Sun Remarketing SCSI Card Reverse-Engineering
« Reply #3 on: February 03, 2022, 03:25:47 am »

Attached is a schematic of the Sun Remarketing SCSI card.

I also have (redrawn) Eagle design files for the card. Twenty years ago I had built my own copy, with self-etched board and Quickboot-compatible EPROM. However, I never published the data because Sun Remarketing was still in business then. So it remained limited to personal use.

« Last Edit: February 04, 2022, 01:27:27 am by patrick »
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jamesdenton

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Re: Sun Remarketing SCSI Card Reverse-Engineering
« Reply #4 on: February 03, 2022, 11:23:26 am »


Would anybody who owns a Sun SCSI card be willing to desolder those two chips and post some pictures of that area of the board so that I can see all of the traces underneath? If not, I totally understand, but I figured that it wouldn't hurt to ask!

I'll keep you guys posted on any progress that I make with the motherboard or the SCSI card and if these projects are successful, I'm thinking about designing PCBs for the 2-port parallel card next!

I have a blank of the SCSI card if you'd like to borrow it for this project. Feel free to DM me.
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AlexTheCat123

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Re: Sun Remarketing SCSI Card Reverse-Engineering
« Reply #5 on: February 03, 2022, 04:37:50 pm »

Thanks for all of the resources guys! This is a lot more information than I was expecting to get and it will be really helpful in quickly finishing up this project!
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Lisa2

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Re: Sun Remarketing SCSI Card Reverse-Engineering
« Reply #6 on: February 03, 2022, 09:58:26 pm »

Attached is a schematic of the Sun Remarketing SCSI card.

I also have (redrawn) Eagle design files for the card. Twenty years ago I had built my own copy, with self-etched board and Quickboot-compatible EPROM. However, I never published the data because Sun Remarketing was still in business then. So it remained limited to personal use.

Note while Sun Remarking is not in business, the rights to the SUN SCSI design was sold before SUN shut down, and the current owner of this IP does not want this information to be open-source at this time.  Likewise the Quickboot ROM has not been open-sourced. 
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patrick

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Re: Sun Remarketing SCSI Card Reverse-Engineering
« Reply #7 on: February 04, 2022, 04:30:32 am »

Understood. This means that this design data will continue not to be published.

For me, the DIY PCB became obsolete when I had the chance to buy an original unpopulated PCB from Sun Remarketing on ebay. And a few years later I developed my own storage solution https://john.ccac.rwth-aachen.de:8000/patrick/idefile.htm, which had the advantage that it could also be used with the "real" LisaOS. I didn't want to have a rare Lisa restored only to use it as a Macintosh.


Of course, this also means that no replica PCBs will be produced (which was the intention of the TO). Perhaps the current owner of the IP rights will decide to produce and sell a new batch of PCBs based on the existing Gerber data?
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AlexTheCat123

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Re: Sun Remarketing SCSI Card Reverse-Engineering
« Reply #8 on: February 04, 2022, 10:39:59 am »

Quote
Note while Sun Remarking is not in business, the rights to the SUN SCSI design was sold before SUN shut down, and the current owner of this IP does not want this information to be open-source at this time.  Likewise the Quickboot ROM has not been open-sourced.

I was under the impression that what I'm doing (and what Patrick did 20 years ago) is okay since I'm reverse-engineering the board myself without access to the original schematics. Of course, if I got my hands on the original files and released them to everyone online, that would be really bad and a clear violation of IP rights, but based on stuff that I've read online it seems that reverse-engineering a schematic from a PCB and making a new PCB layout from it is not IP infringement as long as you're not directly copying/referencing the original design files, which I don't even have access to.

I don't want to cause any sort of conflict over this, but I've put a lot of work into this project and it would be really upsetting if I'm not allowed to share the final product with anyone.
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patrick

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Re: Sun Remarketing SCSI Card Reverse-Engineering
« Reply #9 on: February 04, 2022, 01:08:27 pm »

PCB artwork, drawings and software code is protected by copyright law. Circuits and algorithms might be patented.

So it is legal to draw a schematic from something you own and publish it, but you must not distribute the original documents without permission from the owner.. Assuming there is no patent on the circuit you could create your own pcb artwork, but you must not copy the original one.

At least in Europe patents expire after 20 years, but copyright remains until 75 years after the death of the author.
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AlexTheCat123

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Re: Sun Remarketing SCSI Card Reverse-Engineering
« Reply #10 on: February 04, 2022, 01:46:00 pm »

Quote
PCB artwork, drawings and software code is protected by copyright law. Circuits and algorithms might be patented.

So it is legal to draw a schematic from something you own and publish it, but you must not distribute the original documents without permission from the owner.. Assuming there is no patent on the circuit you could create your own pcb artwork, but you must not copy the original one.

So it looks like it's okay to proceed, right? I'm only going to publish my reverse-engineered schematics, not the originals, and the circuit doesn't seem to be patented so it seems like I'm free to make my own PCB.
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Lisa2

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Re: Sun Remarketing SCSI Card Reverse-Engineering
« Reply #11 on: February 04, 2022, 04:19:10 pm »

So it looks like it's okay to proceed, right?
I am not cool with this.  Legal or not, copying a design chip-for-chip, net-for-net, is plagiarism.  Just because the intention is that the result may be good for all, does not alone justify it.  The owner of the Sun SCSI design has asked that this forum not to distribute this information at this time.  As a forum administrator and the owner of the LisaList2.com domain I wish to proceed with caution, respecting the rights of all the members. 
Rick
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compu_85

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Re: Sun Remarketing SCSI Card Reverse-Engineering
« Reply #12 on: February 05, 2022, 07:45:24 pm »

Who is the owner of the Sun Remarketing IP at this point? Did they buy everything, or just bits / pieces?
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Lisa2

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Re: Sun Remarketing SCSI Card Reverse-Engineering
« Reply #13 on: February 07, 2022, 04:33:58 pm »

Who is the owner of the Sun Remarketing IP at this point? Did they buy everything, or just bits / pieces?
John of VintageMicros bought the remaining inventory from SunRem many years ago and he also acquired from Bob Cook the rights to the SunRem products at that time. 

Later John transferred the rights to the SunSCSI product to another person.  That person is the one who contacted me.

I want it to be clear that I am not John or the current owner of the SunSCSI design.  Nor do I have any interest in VintageMicros, business or otherwise.
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stepleton

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Re: Sun Remarketing SCSI Card Reverse-Engineering
« Reply #14 on: February 07, 2022, 06:28:24 pm »

I hope I won't cause offence with the following --- it's not intended!

Is it known whether the current IP owner intends to sell more of these devices? I know you can get the bare boards from VintageMicros, but the ROM is useful for booting the Lisa, and if that's not for sale, then you'll have to boot MacWorks Plus II some other way. I'm also not sure how easy it is to source the L5380 SCSI controller IC. Incidentally, I found this technical post (by James MacPhail I assume) interesting. It looks like you only need two bytes in the ROM to allow MacWorks to use the card, provided you have some other way of booting MacWorks, like a floppy disk.

(ETA: The ROM situation described in the post is an interesting one. I wonder how easy it is for the IP owner to make working ROM/PAL hybrid assemblies these days.)

I can understand misgivings about copying the PCB net (regardless of legality, which I think permits it for the reasons Patrick said, although I'm no lawyer!). I don't think this is plagiarism: Alex is not trying to say that the card is their own invention.

But if reverse-engineering and copying the net isn't fair play for other reasons, then we can abide by that, especially on this forum. Suppose instead you identified the "theory of operation" of the card and built some kind of replacement that MacWorks could use in the same way --- would this be all right?

It seems pretty likely that the card is the L5380 IC and some glue logic, and that basically MacWorks talks to the L5380 pretty directly. One of the chips on the card is a flip-flop, so there's a little additional state, but the rest is buffers and logic gates from what I can tell. Some of the glue logic may be for switching between the way the Lisa expects to talk to the ROM (using 16-bit 68000 peripheral interfacing) and how the MacWorks software might talk to the L5380 (which would be different if it uses 8-bit 6800 peripheral interfacing). The AppleNet card does the same thing.

The L5380 datasheet can be found on pages 424-447 of this PDF. I would bet MacWorks might only use a subset of the L5380's features, and you might be able to guess what they are by looking at the card's wiring or by examining MacWorks itself. From that knowledge you could make a new, compatible card, maybe one that makes use of modern ICs and a microcontroller that wouldn't be too hard to source. There's a lot of open-source activity these days in creating disk-emulating devices like BlueSCSI, so it may be possible to reuse some of that work here to recreate an L5380-based computer SCSI interface.

Alternatively, suppose you did have access to some L5380s, plus knowledge of what the support chips are doing (some logic function plus some state). You got this knowledge by understanding what the SCSI card logic does and/or by reverse-engineering MacWorks. You think you can probably replicate that same logic with a couple of GALs and some buffers, which you also have to hand, or maybe with your own 74-series design, or maybe with some other kind of programmable device.

Would either of these options be possible to discuss here? I promise I'm not trying to play games by asking. These alternative routes to a MacWorks-compatible SCSI card are ones that Alex or someone else might enjoy, and that bystanders like me would probably find enjoyable and educational to read about and discuss. If it's allowable on the premier Apple Lisa forum on the internet, then it's good to know it's an option. If not, there's always other projects.
« Last Edit: February 07, 2022, 06:48:43 pm by stepleton »
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