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maceffects

Mac SE/30 PDS & Power Questions

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As some of you know I'm working with an engineer on making a functional replacement for the Micron Xceed with internal grayscale functionality.  Given the increased BOM for FPGA/DAC I decided that I would go with a SoM to allow the project to be open-source and software guys can make use of the USB/ethernet/WiFi/Bluetooth.  Thus far we have a concept that will allow the Mac SE/30 to have the Xceed internal grayscale functionality and allow the Mac SE/30 to be switched to run Ubuntu with a dual-core Cortex A9 667mhz processor.  The output would go to the SE/30's display at 256 grays. 

 

Anyway, a lot more development work is needed, however, I would like to know (if anyone knows) the unused power supply on the 12v system on the SE/30.  Our design appears to use around 300mA.  I'm thinking of having an Molex connector on the card to draw in since I doubt the PDS slot would be happy about this.  Is the SE/30 power supply sufficient for this task?  Also, does the SE/30 PDS have any ability to interface with the ADB system?  If not, we will have to have a loop-back cable which would not have the best appearance. 

 

General feedback is also welcome. 

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Interesting project. So is the Cortex processor going to be present on all variants or is it an add-in sort of thing? Personally I'd only be interested in the grayscale adapter part; I wouldn't use most of the rest of it.

 

As for Ubuntu, has anyone tried to see how usable it would be at that resolution? Most modern installs give me fits if trying to run on anything under 1024x768@24bpp, so I can't imagine it would be happy with 512x384@8bpp. 

 

PDSes were different from machine to machine, some with pass-throughs for additional signals such as sound and others having (or missing) lines to control cache or FPU presence. I don't think ADB was ever available at any PDS though. You'd probably have to build a Y-cable with one end going to the SE/30's ADB port and the other to your expansion card's ADB input which you could build into the external slot interface. It wouldn't ruin the aesthetic too much.

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8 hours ago, Franklinstein said:

Interesting project. So is the Cortex processor going to be present on all variants or is it an add-in sort of thing? Personally I'd only be interested in the grayscale adapter part; I wouldn't use most of the rest of it.

 

As for Ubuntu, has anyone tried to see how usable it would be at that resolution? Most modern installs give me fits if trying to run on anything under 1024x768@24bpp, so I can't imagine it would be happy with 512x384@8bpp. 

 

PDSes were different from machine to machine, some with pass-throughs for additional signals such as sound and others having (or missing) lines to control cache or FPU presence. I don't think ADB was ever available at any PDS though. You'd probably have to build a Y-cable with one end going to the SE/30's ADB port and the other to your expansion card's ADB input which you could build into the external slot interface. It wouldn't ruin the aesthetic too much.

The Cortex A9 will be on all variants as it is included on a SoM that already has the FPGA system built-in.  That said in the base configuration it wouldn't be used as it wouldn't include ADB loop-back and such, thus it would be cheaper.  The problem is that the FPGA solution requires many I/O for the PDS.  There is a pre-packaged board that will be attached to our PCB to use Xilinx XC7Z020 which has enough capability.  This has 106 user I/Os which is what we need, also DAC is involved on the board.  My goal is to have a Grayscale only card be around $350 and the Linux compatibility version be around $395.  The benefit of a SoM is that future additions of Ethernet, USB, etc simply require FPGA update and Mac OS driver functionality.  Since the final project will be be open source enough it will allow others to make the software side of things work. 

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Oooooo I have dreamed about somewhat of a similar concept for many years, but nothing that ever came to fruition. But looks like your working on it in a way. 

 

So, why not take it a step further... Use the ARM as a co-processor to the Mac. It could crunch the javascript heavy rendering engine of a web browser. While the "chrome" runs on the System 6/7 Side. this would give the authentic look and feel of the browser running under the MacOS, but be able to handle a modern website. Especially if the ARM is also part of the video card circuitry, it can "frame up" the output of the rendering engine to be within the window of the chrome, making it seemless. Or, even playing youtube videos. since the video playback would be written into the framebuffer with the underlying linux kernel. 

 

Getting carried away, I know. But hey. 

Edited by techknight

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8 hours ago, techknight said:

Oooooo I have dreamed about somewhat of a similar concept for many years, but nothing that ever came to fruition. But looks like your working on it in a way. 

 

So, why not take it a step further... Use the ARM as a co-processor to the Mac. It could crunch the javascript heavy rendering engine of a web browser. While the "chrome" runs on the System 6/7 Side. this would give the authentic look and feel of the browser running under the MacOS, but be able to handle a modern website. Especially if the ARM is also part of the video card circuitry, it can "frame up" the output of the rendering engine to be within the window of the chrome, making it seemless. Or, even playing youtube videos. since the video playback would be written into the framebuffer with the underlying linux kernel. 

 

Getting carried away, I know. But hey. 

Interesting concept, I like it!  Sounds like 90% of that is heavy lifting from a software prospective.  That is something neither my engineer nor I have the skill set for.  However, if anyone is interested in joining the project...  Let me know :)

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And thats why the project never came to fruition. I am a hardware guy, not a software guy. 

 

I just started dabbling into 68K code writing very recently. But not mac related. All bare metal stuff. 

Edited by techknight

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Yeah, but I'm hoping the project will be open-source and serve as a platform for others to do fun things with as they please.  I just hope the Mac SE/30 is an interesting enough platform for people to want to work with.

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Hey, this is a different take on a project I was considering taking on! My main focus was to output color to a modern external display rather than provide grayscale to the internal one, but this still sounds very interesting, and I definitely don't have any engineering experience in my project. :)

 

I was hesitating about including an FPGA in my project, because I feel like it should be possible to go without it, and leaving it off would definitely lower the price. But more power to you if you have the resources to handle that. Any chance your SoM has an exposed HDMI port we can try and get working post-launch?

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19 hours ago, techknight said:

And thats why the project never came to fruition. I am a hardware guy, not a software guy.

Yeah I'm pretty sure at least 3/4 of the vintage computer people (myself included) are more on the hardware side than software. I mean if you only want to use old Mac software you'll just download mini vMac or Basilisk or Sheepshaver or whatever emulator, not futz around with ancient finicky mounds of increasingly brittle plastic and metal that take up loads of space and require regular maintenance to continue operating and that cost tons of money to fix when they inevitably break (or if you want something like an original XCeed card, for which most people would have to sell one or more children for medical experiments to be able to afford). So here we sit, heads filled with grand ideas and fully realized hardware mods and nobody to write anything that uses it. Tragic. Good programmers are hard to find.

 

19 hours ago, maceffects said:

I just hope the Mac SE/30 is an interesting enough platform for people to want to work with.

People love these old things but so far they've basically been limited to the original mid-80s experience (read: slow and monochrome) or a mod (several people have gutted classic Macs to use the cases to house iPads or minis with small LCDs). Once this project is released an unintended side-effect may be to drive up the cost of SE/30s since now you'd be able to do modern things at a reasonable speed, all in the comfort of your authentic vintage Mac. I'm just glad that I bought six of them before your case project was released to the world.

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On 6/1/2020 at 11:15 AM, techknight said:

Oooooo I have dreamed about somewhat of a similar concept for many years, but nothing that ever came to fruition. But looks like your working on it in a way. 

 

So, why not take it a step further... Use the ARM as a co-processor to the Mac. It could crunch the javascript heavy rendering engine of a web browser. While the "chrome" runs on the System 6/7 Side. this would give the authentic look and feel of the browser running under the MacOS, but be able to handle a modern website. Especially if the ARM is also part of the video card circuitry, it can "frame up" the output of the rendering engine to be within the window of the chrome, making it seemless. Or, even playing youtube videos. since the video playback would be written into the framebuffer with the underlying linux kernel. 

 

Getting carried away, I know. But hey. 

Ha! If this ever happens, I look forward to one-upping all of my friends with Amiga PPC accelerators with some casual web browsing ;)

 

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@cheesestraws does some 68k programming so may be able to help, possibly.

 

There was also the guy who wrote some 68k software so that he could add Wifi functionality to System 7?

 

In terms of this matching the Micron Xceed functionality, will it also provide support for an external colour display?

 

@maceffects Sign me up for the non-Linux version, I am primarily interested in getting the Micon Xceed functionality at a reasonable price.

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On 6/4/2020 at 4:48 AM, joshc said:

@cheesestraws does some 68k programming so may be able to help, possibly.

Kind of you to think of me, but unfortunately I'm nowhere near competent enough at the kind of low-level programming this would require.  Aside from some dilettante dabbling, I'm most comfortable firmly in application space :-)

 

That said, definitely sign me up for a Linux version (modulo financial disaster).  I'd love to have a go at getting the "split world" stuff going (someone hacked rootless mode into Basilisk a while back, I was wondering if using the same approach but in reverse might work to allow handing over parts of the Mac desktop to the Linux side to draw...)

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So is the Linux mode of this board supposed to supplement or supplant the host? While the former would be neat it would be very software-intensive in both classic Mac OS and Linux. However you may be able to build a version of this board that takes over the SE/30's logic board entirely: the upgrade board would just ignore the SE/30's CPU and memory subsystem and basically only use the original ports to allow connectivity to external devices including your ADB keyboard and mouse. The A9 would run Linux, possibly with a Mac OS emulator to allow any version of Mac OS to run, including PPC versions if you have Sheepshaver (or not; I'm not sure what the performance level of this chip really is). Or you could do everything natively in Linux, potentially including light web browsing, on your 512x384 screen. Or you could reboot and, via either software control or a physical switch, select the option to run as just an SE/30 with a Micron XCeed clone. I'd prefer a physical switch, myself, because it would be a quick and clear setting. 

 

While we're dreaming, how about a flash-based storage module as an option that's accessible by the host Mac? Perhaps it could be added, along with other future ideas, via an expansion header in Arduino or Pi style. If you're replacing the hard drive with flash anyway you'd likely get much better performance with your storage attached to the 32-bit 16MHz SE/30 PDS rather than the 8-bit SCSI-1 controller on the logic board, and this may be cheaper to implement than a ~$100 SCSI2SD drive. The SE/30's ROM may need modified to boot from it though.

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