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Thread: IIfx RAM


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Permlink Replies: 67 - Pages: 5 [ Previous | 1 2 3 4 5 | Next ] - Last Post: Apr 13, 2019 10:02 AM Last Post By: wanbuilder Threads: [ Previous | Next ]
bbraun


Posts: 493
Registered: 7/25/12
Re: IIfx RAM
Posted: Aug 3, 2015 1:40 PM   in response to: trag in response to: trag
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I did!
dougg3

Posts: 190
Registered: 8/13/12
Re: IIfx RAM
Posted: Aug 3, 2015 7:15 PM   in response to: trag in response to: trag
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Yeah, I think that was bbraun. Osmond looks pretty cool! Honestly though, I don't use OS X on my main workstation. I'm still not really happy with any of the PCB design software options. Eagle gives me the most familiarity, but KiCad seems like a good future choice. KiCad still feels a little flaky, but I know it's improving a ton.
fraveydank

Posts: 73
Registered: 4/23/15
Re: IIfx RAM
Posted: Aug 3, 2015 8:02 PM   in response to: dougg3 in response to: dougg3
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I've used Osmond, both back in the Classic days and after the OS X update. It wasn't bad, though it didn't offer many advanced features (no impedance control, had to route and length-match differential lines by hand, etc.) and it was slow as a dog on anything larger than very simple designs, even on a dual 1 GHz G4 (fast back then). On the plus side, it has text-based file formats that we're easy to manipulate both by hand and by script; I made a Perl script to extract pick/place data from the raw PCB file (which was good, because there wasn't an option to export it).

These days I use KiCAD. It's not the best; it specifically lacks a lot of export options and any back annotation capabilities from layout to schematic. It's reasonably stable, though (I've used a lot of $10k+ commercial packages that crashed a lot more). And unlike Osmond (unless this has been added since about 2008), it has a schematic editor, which actually turns out reasonably pretty schematics (they can only be hierarchical, though, which can be a pain for things that only need to be a few pages). Only problem is that its OS X port sucks really bad; it's completely put me off ever using wxWidgets for anything, ever. It's way faster running under XP in a VM on my Mac, though I usually just use my Windows machine for it.

I've done some reasonably complex projects with KiCAD and I'm happy to recommend it. I also hear good things about the gEDA schematic/layout tools, though I've only played with those a bit.
bbraun


Posts: 493
Registered: 7/25/12
Re: IIfx RAM
Posted: Aug 3, 2015 9:25 PM   in response to: fraveydank in response to: fraveydank
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As a beginner with PCB layout, I think OsmondPCB has more gotchas than most. I've found the default hole size when using the builtin DIP and header libraries to be too small for through hole components, where things like Eagle default to a reasonable hole size for through hole components, when using through hole library bits. It also defaults to labeling things like U1, U2, etc, but doesn't include a font, so everything gets rendered as "- -" out of the box.
I do like the text file representation, I've started to script some checks of my design for things I've gotten wrong in the past, to prevent making the same mistakes again. Regression testing for my brain, sorta.
Now that I've got things setup, and have done a few designs, I'm getting the hang of it a little more.
fraveydank

Posts: 73
Registered: 4/23/15
Re: IIfx RAM
Posted: Aug 4, 2015 8:40 AM   in response to: bbraun in response to: bbraun
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Osmond wasn't bad as things go. It mostly takes practice to know in your head that most through-hole parts like 35-mil holes; I suppose that could be the fault of the tool for not having it as a default, but layout is just one of those things you learn by doing. I will say that Osmond has one of the nicer "rubber band" point dragging tools out there; manipulating already-drawn lines in KiCAD is laborious and occasionally nightmarish.

Neither of them feature an autorouter, but I'm inclined to see that as a Good Thing; autorouters usually turn out garbage and by the time you've tweaked their output to be even somewhat acceptable, you've spent as much time as you would have doing it correctly by hand.
techknight

Posts: 110
Registered: 10/13/12
Re: IIfx RAM
Posted: Aug 18, 2015 9:20 PM   in response to: fraveydank in response to: fraveydank
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Are there any schematic/PCB layout software for the 68K macintosh, or early PPC? Just curious. As a heavy Eagle user, it would be kind of unique/fun to design a board on a classic machine.
fraveydank

Posts: 73
Registered: 4/23/15
Re: IIfx RAM
Posted: Aug 18, 2015 10:46 PM   in response to: techknight in response to: techknight
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Well, there's Douglas' CAD system. Older versions ran on 68k. It doesn't generate Gerbers unless you paid for the "plus" version (the regular version was $25 but only worked with their own system, but you could pay $500 for one that spat out Gerbers too). It's a little primitive, but not bad, but I also don't know if they still support the old system and, if so, what their pricing is. They were the best deal around in the '80s and early '90s, especially if you lived in the SF Bay area.

Douglas is still around, but I don't know in what capacity. They still seem to be selling their CAD system, though: http://www.douglas.com/index.php/circuit_board_design_software/

I think early versions of Osmond might have had a 68k version, but I don't know if I have any of those kicking around.

In either case, they're only layout software; you still need an external schematic capture package, or you need to do the netlist by hand (which is actually not that bad for small designs).
yuhong

Posts: 2
Registered: 8/15/15
Re: IIfx RAM
Posted: Feb 4, 2016 12:05 AM   in response to: dougg3 in response to: dougg3
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It seems there is enough room for at least 350 mil chips mounted the same way, right? I wonder what about 400 mil that early 16Mbit DRAM chips used.
Trash80toHP_Mini

Posts: 45
Registered: 10/19/12
Re: IIfx RAM
Posted: Feb 14, 2016 11:44 AM   in response to: yuhong in response to: yuhong
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Fab projects guys! If wider parts are problematic there might be a solution. I don't know if it's really feasible, but a while back I suggested a way to toaster process double sided boards and someone knowledgeable thought it was a good idea. There appears to be enough working temperature differential between leaded and non-leaded solder pastes to "toast" the second/top side without reflowing the first/underside?
fraveydank

Posts: 73
Registered: 4/23/15
Re: IIfx RAM
Posted: Feb 14, 2016 11:50 AM   in response to: Trash80toHP_Mini in response to: Trash80toHP_Mini
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It's definitely doable; I've done it. However, there's usually more cleanup involved, and I lost my leaded toaster oven in a move about five years ago. I have a rework heat plate (Puhui T8280, cheap but not terrible) and a hot air rework station (Xtronic 4040, same story) which do the job a lot more precisely and also work for removing things if you need to. But the overall investment in those was about $250, whereas the toaster oven cost me $20 used (and its toast cycle turned out to be usable for most soldering purposes, so I never even installed a temperature controller).

I do tend to stay away from lead-free solder, though. It's really terrible in a lot of ways, except for the environmental ones (and probably a few of those, too, if maybe not as much as lead).
fraveydank

Posts: 73
Registered: 4/23/15
Re: IIfx RAM
Posted: Feb 14, 2016 11:51 AM   in response to: fraveydank in response to: fraveydank
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Bear in mind that if your board isn't too cramped, you can either avoid SMT parts entirely on the back, or restrict it to small passives (e.g. 0804 or smaller) which will stay on with just solder surface tension. That's really the best strategy.
LittleBlackDuck

Posts: 1
Registered: 7/2/15
Re: IIfx RAM
Posted: Apr 29, 2016 1:44 AM   in response to: fraveydank in response to: fraveydank
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Hi all,

Has been a while since the last post to this thread... have there been any updates at all? Anybody selling these completed modules anywhere?

Cheers

Ducky
fraveydank

Posts: 73
Registered: 4/23/15
Re: IIfx RAM
Posted: Aug 1, 2016 2:38 PM   in response to: LittleBlackDuck in response to: LittleBlackDuck
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I wish. I have a sack of PCBs, a 1000-pc reel of RAM chips, a hot-air rework station and absolutely zero time (because I have two jobs and two young children). I'm hoping to make some progress on this soon; I did solder up a test unit, but I found that I've forgotten how to make the solder paste flow smoothly from a hand plunger. Been frustratingly slow movement. I'm inclined to sell kits at cost, though ($12.50 per SIMM for PCBs, RAM chips and capacitors) once I've actually managed to get a quad of them built up so I can guarantee that the RAM chips weren't counterfeit.
joethezombie

Posts: 2
Registered: 1/25/16
Re: IIfx RAM
Posted: Jan 22, 2017 1:39 PM   in response to: fraveydank in response to: fraveydank
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A semiannual inquiry: Any movement on these? I'd be interested in some (even untested) kits.
fraveydank

Posts: 73
Registered: 4/23/15
Re: IIfx RAM
Posted: Jan 22, 2017 5:33 PM   in response to: joethezombie in response to: joethezombie
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I gotta get my act together and assemble them. I just went from two jobs down to one, plus got a better hot air station, so I'm hoping I'll have the time soon.

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