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SE/30 logicboard recreation


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I'm 100% an end-user and lack hardware-engineering skills, so please believe me when I say HOLY CRAP YOU DID IT :D :D :D 

 

Not even kidding, if / when you make these boards available to purchase I'll absolutely be in line to buy at least one, likely two.

 

Just astounding, incredible work, @Bolle. I jumped off my chair when I scrolled down to the pic of your SE/30 booting from the new board!

 

Huxley

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Man, I'm insanely jealous of your guys' technical skill.  I wish I had gone into electronics, but a few things got in the way ... like math.

 

@Bolle  I know you're busy with all these cool things, but, have you considered designing a new custom Mac motherboard layout just for fun? A truly new "prototype" Mac would be awesome.  Like a desktop variant SE/30 board with 3 PDS slots (Workgroup Server 30).  Or a 3 or 4 NuBUS slot variant of the Quadra 700 (Workgroup Server 750? :))

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21 hours ago, olePigeon said:

Man, I'm insanely jealous of your guys' technical skill.  I wish I had gone into electronics, but a few things got in the way ... like math.

 

@Bolle  I know you're busy with all these cool things, but, have you considered designing a new custom Mac motherboard layout just for fun? A truly new "prototype" Mac would be awesome.  Like a desktop variant SE/30 board with 3 PDS slots (Workgroup Server 30).  Or a 3 or 4 NuBUS slot variant of the Quadra 700 (Workgroup Server 750? :))

 

LOL that would be hilarious. in an ATX form-factor too! because why not? 

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heh I do indeed like the idea of this interesting project too

 

this is just my own somewhat wild opinion but....

if we were to start putting custom features on I'm wondering if there is anything difficult stopping it from willingly recognizing a single 128KB or larger vram chip instead of the original-design 64KB?

I mean a variation of this board with different rear port positions especially re the extra vram going to a DA15 port instead of internal display would give us a drop-in replacement board for the LC series cases abit we would probably have to sell them with the warning that they are compatible with a SE PDS card rather than the more usual LC PDS card tho (least anyone tried put an ex-lc475 asante ethernet card onto this 'new' board!)

 

I know that sourcing DA15 instead of DE15 may not be as easy but its only because I'm not so sure DE15 would easily fit into unmodified cases that is

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On 3/17/2021 at 2:10 PM, olePigeon said:

Man, I'm insanely jealous of your guys' technical skill.  I wish I had gone into electronics, but a few things got in the way ... like math.

I understand.  I'm very apprehensive about it myself, but I'll get through it eventually!

 

c

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On 3/18/2021 at 1:24 AM, rplacd said:

Out of curiosity, what's the socketed accelerator you've cloned there? Not the PDS one sitting on your desk – although I'm now pretty curious about that too ;)

 

He's cloned both the Carerra 040 and the Daystar Turbo 040.

 

Edit:  Oh, I see what you mean.  Looks like the socketed Daystar accelerator. :)  Apparently he's cloned that one, too. :shocked:

 

Edited by olePigeon
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On 3/18/2021 at 9:24 AM, rplacd said:

Out of curiosity, what's the socketed accelerator you've cloned there? Not the PDS one sitting on your desk – although I'm now pretty curious about that too

 

That's indeed a clone of the socketed Daystar SE/30 PowerCache. I've built clones of the P33 and P34 Universal PowerCache as well as the SE/30 DiiMO with PDS passthrough and IIci DiiMO (which I couldn't get to work  yet in the IIci for some reason - but it does work in the SE/30 with an adapter :rolleyes:)

 

...and Turbo040 and Carrera040 have already been named.

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No, because it doesn't make sense to distribute something that's not yet gone through all the testing I want to put it through ;)

 

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20 hours ago, Bolle said:

Who can spot what's going on here?

It looks like you've replaced several of the original SE/30 (video?) chips with modern Atmel Microcontrollers!

 

This project is so amazing -keep up the good work! :)

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Posted (edited)
20 hours ago, davidg5678 said:

It looks like you've replaced several of the original SE/30 (video?) chips with modern Atmel Microcontrollers!

Correct. Was going to say to @pcamen the fact that there's Atmel chips on there is noteworthy on its own already :)

 

Spent the last 3 days writing equations to match the behavior of the original PALs. One was easy, as the original from one of my spare boards was not protected at all and I could just read out the fusemap.

The other 5 were protected so I had to observe their behavior and rewrite equations to mimic it. A few of them were quite easy because the schematics already make it obvious what they do.

I did underestimate the 16L8s though. Being purely combinatorial makes you think it's going to be easier than figuring out a registered PAL - that's not true as soon as there are latches implemented.

Those are next to impossible to detect through automated dumping/state analysis.

Most of the time I spent trying to figure out what appears to be the VRAM controller in UE6 and UE7 with its refresh statemachine. The equations just wouldn't minimize to fit into the 8 product terms that you're limited to on 16(L,R,V)8 devices.

Took forever and a lot of manual trial to rule out "don't care" conditions and error to get there.

 

What I got now seems to be working fine, I'll go through some more testing though to see if it's stable. The PALs are responsible for generating sync signals for the CRT... if something goes wrong and you send a wrong vsync signal there is the chance to grill your analogboard/flyback/HOT...

 

Encountered a few interesting errors along the way...

 

There were slight artifacts whenever the contents on the screen changed when write and refresh cycles overlapped sometimes, because the condition to enter a refresh cycle was not specific enough:

https://imgur.com/KOjbQYc

 

And this is what happens when /vsync isn't timed correctly:

 

IMG_6264.thumb.jpg.e8ff3216b4c32b93499388abbbfce625.jpg

 

 

 

20 hours ago, codyNC90 said:

The bus speed doubled?

 

This is an interesting idea... Will have to look into that.

Edited by Bolle
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