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SE/30 Xceed greyscale adapter cloning thread


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Starting this thread to discuss the possibility of creating cloned versions of the Xceed greyscale adapter for the SE/30. 

 

I'd be willing to throw in some money to help get this off the ground.  My interest would just be getting my capital back, if possible, not making any profit. 

Edited by pcamen
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Bring in comments from the eBay Finds Thread

 

@Bolle said:

 

3 hours ago, jessenator said:

Micron Exceed schematics

I think those are available on the net already. At least I got a copy flying around here somewhere I thought.

Also buzzed out my card for mostly complete schematics before I knew those were already out there.

 

3 hours ago, jessenator said:

(presumably) code for all the custom chips

Make that one custom chip. If those documents really contained the hardware description of the main video controller that could easily be converted to some modern FPGA.  The four GALs are very similar to the XCeed 306-48 judging from the signals that are present.

 

@maceffects said:

 

@pcamen I think the market is larger based on my experience. This is something more people would want than just a accelerator.  I would suspect $250-$350 is appropriate. With a market size of around 200-250 (sold within a 1 year period).   

 

If you are serious about this, there is a place that makes the rear video adapter and harness. I suspect this would be a good project.  Unfortunately, given the various projects I’m involved with the savings is running low on my end. But I’d be happy to facilitate this.  I have tons of contacts in China and have basic Mandarin skills.  

 

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I'd be interested as well.

 

Wasn't there a development thread for this? Not that a renewed spark of interest would hurt anything :)

 

Is this something the spearheader would want to be kept under their supervision (funding) or something to take to a crowdsourcing medium?

 

I wonder, too, if this could be a BYOadapter situation. There are kits for the yoke already at least. Personally, I'm not too interested in an external monitor connection, but I might be in the minority.

Edited by jessenator
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I'd be interested in this as a buyer of it. I don't have many skills that would help with the creation of it I'm afraid.

 

Ideally a single card that provides internal greyscale, external colour + Ethernet on a single card would be neat, but I'm sure that would add a lot of complexity to this project.

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As I mentioned over in the eBay thread, the biggest impediment to getting a project like this off the ground is the inevitable project creep.  There was a discussion about creating an accelerator for the SE/30 that ultimately went nowhere, and I'd wager that a major part of that was because it was too ambitious a project:

 

 

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I think we should design a card that has WiFi, processor upgrade, and video all in one!  Just kidding, though I wish it was possible.  Scope creep should be my middle name.  But realistically, if we find an electrical engineer who is also familar with Macs I think we can do this.  I know I can have a board sent to a place I know in China for reasonable reverse engineering including some of the chips.  But, it would result in the card sent being a sacrificial lamb. 

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5 minutes ago, maceffects said:

I know I can have a board sent to a place I know in China for reasonable reverse engineering including some of the chips.  But, it would result in the card sent being a sacrificial lamb. 

Maybe not feasible (too bleeding edge?), but I heard on GamersNexus HW recap about this: https://www.electronicsweekly.com/news/business/non-destructive-way-2019-10/
non-destructive means is interesting. 

 

I for one, am perfectly content for "recreate the Color 30" straightforward approach. No creep :) 

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2 minutes ago, maceffects said:

I think we should design a card that has WiFi, processor upgrade, and video all in one!  Just kidding, though I wish it was possible.

That's not really impossible, but move the WiFi to a 10bT dongle and forget about Video Out, that one is definitely feature creep IMO. [}:)]

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On 10/15/2019 at 8:38 PM, pcamen said:

I'd love an external monitor connection that could do more than 640x480, in addition to the internal greyscale.

Yes! And accelerated graphics would be great! I would back an SE/30 Xceed greyscale adapter cloning project. :-) 

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On 10/15/2019 at 2:18 PM, Trash80toHP_Mini said:

That's not really impossible, but move the WiFi to a 10bT dongle and forget about Video Out, that one is definitely feature creep IMO. [}:)]

Doesn't the original card have external video? I'd absolutely pay for a device that simply gave grayscale ability to the SE/30, but if the original had color video out then I'm not sure it's feature creep. I think grayscale is the most important though, if we could just do that it'd be nice.

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Oh, I see. Considering the SE is portable, I imagine duplicating the video it has would be more useful than giving it new, more varied video output abilities for the purpose of tying it down to a second monitor. And as far as I know a way already exists for duplicating the internal video, so it's a comparatively short hop.

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SE/30 PDS has three interrupt lines, so could support an internal grayscale only video card, an external output video card and a network card. The limitation is that the PDS is is only (capable?) spec'd for driving two TTL inputs as opposed to the three needed for such a combination which would be further complicated by acceleration.

 

A baseline graycsale card for internal monitor support only would be the first step as I see it. Output to drive an external display in color would be the second step, whether done in the XCEED A/B switch method with its limited 640x480 resolution or by implementing two nearly identical setups for driving both at the same time as an added feature.

 

XCEED card's external refresh rate is the sticking point as I see it. If it's not 60Hz, I'd go the second route after first developing the internal grayscale card. More and better pixels compatible with a modern panel would be the way to go. The wider 640p standard scales perfectly to 720p and the 1080p common denominator of current panels.

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We definitely need to control feature creep. That is what ends up making projects like this DOA, because the creator(s) end up trying to do too many things at once, and inevitably get overwhelmed.

 

I, for one, would hate to see that happen here, because I've wanted an Xceed for some time now, but the prices just keep going up, and my budget isn't getting any larger anytime soon, and it would be super neat if I could get a clone of one for a much more affordable price.

 

Keep it simple, and it will have a very good chance of getting somewhere!

 

c

Edited by CC_333
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What I'm saying is feature creep would be anything more complex than getting a clone of just its internal grayscale function up and running. Anything aside from that singular basic function is feature creep. Sending any signal outside the box is a second step and is certainly is not the EXCEED card's strong suit. 680x480@8bit is pathetic, not really worth pursuing on its own IMO. If what's wanted is a "real" copy of that card, that would be another thing.

 

KISS, get the internal grayscale part done first and worry about the rest  .  .  .  if and when. :approve:

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@Trash80toHP_Mini Agreed totally!

 

In this day and age, having a semi proprietary external monitor hookup which can only drive an ancient and very difficult to find monitor at a relatively low resolution isn't worth bothering with at this point.

 

Get the internal grayscale circuits copied *first*, then go from there.

 

One minor feature that could be nice to have (at some point!) is to build in a fast QuickDraw accelerator, but something like that may end up happening inadvertently nevertheless, simply because it'd be a side effect of using modern components, which I'd imagine tend to be inherently faster than the older equivalents used on the original Xceed.

 

c

Edited by CC_333
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No expert here, but I don't think so. May need to disable a hardware check or tweak the driver to default to internal?

 

You're still cloning the "entire" card, but simplifying the implementation by removing a sizeable portion of the schematic, hence traces, gates and cable drivers for the external display. That can be picket up at later date in the original form as a second step. Dunno if an 8-bit RAMDAC is even available as a new part, so it might be necessary to substitute a far more capable part.

 

I think the notion could be most clearly illustrated by graying out much of that cable mess needed to support the external monitor. It might be reduced to just a triangle or even a simple V, dunno, the wiring harness is a separate schematic.

 

edit: if a 24 bit RAMDAC capable of supporting something on the order of 720p fallback part is needed as a substitute. Adding more VRAM to support higher resolutions or even the original's 640x480 in 24-bit becomes a possibility.

Edited by Trash80toHP_Mini
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46 minutes ago, Trash80toHP_Mini said:

if a 24 bit RAMDAC capable of supporting something on the order of 720p fallback part is needed as a substitute. Adding more VRAM to support higher resolutions or even the original's 640x480 in 24-bit becomes a possibility.

But only *AFTER* a working clone of the card gets created first!* Only THEN can extra features be considered.

 

c

 

*I don't mean to harp on this, but it's of utmost importance to tightly control feature creep by prioritizing getting a working clone developed first, or else this project will end up being a train wreck.

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