Thread
Macintosh Classic II, FPU / Math Card (Picture)
Posting this only because i have never seen one yet, until now.
Oooh - very nice! Any pictures of the other side?
nope just the one picture 
I'm not going to lie, The little kid in me wants that all for my self, that is why i did not post the ebay link.
I think my 2 year old is rubbing off on me ;-)
I think my 2 year old is rubbing off on me ;-)
by the way, the seller is a cool dude.
He shot a pic of the rear for me
He shot a pic of the rear for me
Well that is interestingly simple, no?
With a classic memory module an fpu and some time could you recreate it?
2 caps, some wire wrap, and a FPU and one could re create it.
interestingly simple, Yes.
interestingly simple, Yes.
So ill send you a memory and fpu and you can make it happen after you buy it?
haha, i dunno
from the seller, Info on the 2 caps on there.
A little info on those caps.
http://www.picaxeforum.co.uk/showthread.php?15901-K5M-104-Capacitor-Polarity
http://www.picaxeforum.co.uk/showthread.php?15901-K5M-104-Capacitor-Polarity
Still need to know what's going on under the chip, and the connector.
Buy it and dissect it!
Buy it and dissect it!
Some bidder sniped it and won it for a dollar over my max bid.
My max bid was 41 bucks. I did not want to pay over that,
I already have the wire wrap, I have those caps in-stock, I have a 16mhz FPU.
I will solder the wires right to the header on the motherboard.
maybe get a little hobby pcb from the shack, to set the FPU on.
I don't have the time to do this now, but it appears less complicated then the InternalHardDriveinaPluShAcK™lol
My max bid was 41 bucks. I did not want to pay over that,
I already have the wire wrap, I have those caps in-stock, I have a 16mhz FPU.
I will solder the wires right to the header on the motherboard.
maybe get a little hobby pcb from the shack, to set the FPU on.
I don't have the time to do this now, but it appears less complicated then the InternalHardDriveinaPluShAcK™lol
FWIW, the ClassicII dev note has the pinout of the connector. It's pretty much just directly throwing the 68882 on the bus, with the only trick being the 16 bit bus, so doubling up the data lines and using the /DSACK 0 & 1 signals.
I've put some labels on those pictures, to illustrate. For the most part, the labeling refers to the 68882 pins, not necessarily the Classic2's connector. For instance, D16 on the Classic2's connector goes to D0 on the 68882, and I've labeled it D0:
You can also put a ROM in that socket, up to 3MB worth.
I've put some labels on those pictures, to illustrate. For the most part, the labeling refers to the 68882 pins, not necessarily the Classic2's connector. For instance, D16 on the Classic2's connector goes to D0 on the 68882, and I've labeled it D0:
You can also put a ROM in that socket, up to 3MB worth.
you are the F'in man!
So, you could put a little 7.x boot image in ROM and do the Classic trick in a Classic II?
I'm really not sure about that. I haven't looked at the ClassicII ROM in particular. There's a good chance it has the EDisk driver, which is what the Classic used to boot (also RAM disk driver, and pcmcia flash card in laptops). That driver looks over some set of addresses (I don't recall how it determines that), for a valid header. So, it might be possible you could put a valid EDisk driver's ROM disk image into ROM there and have it automagically bootable.
I managed to locate images for a Classic II FPU of a non-socketed design:
Nice, how many layers is that board?
Did you guys noodle out the PCB puzzle yet? I doesn't look too bad, especially now with two different layouts to match each other against the documented pinouts of the Memory Slot and the FPU.
Nice graphic, mcd!
Did you guys noodle out the PCB puzzle yet? I doesn't look too bad, especially now with two different layouts to match each other against the documented pinouts of the Memory Slot and the FPU.
Nice graphic, mcd!
no, but i am still slightly motivated to make one!!!!!!!!!!!!!!!!!!!!!
! don't know why either. maybe only because there is very few classic II's out there with a FPU installed??
! don't know why either. maybe only because there is very few classic II's out there with a FPU installed??
If you make one, I'll buy it.
i'm thinking of soldering wires right to the rom/fpu pins from the FPU?
and maybe gooping the fpu upside down to the rom's or something?
and maybe gooping the fpu upside down to the rom's or something?
Oh, I thought you meant an actual card.
nope, care if i experiment on your classic ii?
I don't have mine any more, ben needed it more then me.
I don't have mine any more, ben needed it more then me.
It's no problem with me. Hopefully once you get it open it will be up to the task. It needs some TLC.
I'm always glad to contribute to the gestalt of Mac 68k knowledge.
lol just kidding, your classic II is just gettin a cap job, I wouldn't be all soldering wires from your rom/fpu slot
Meh. You're a professional. I'd trust you to restore the FPU slot/ROM connections to their original state when you were done.
If somebody came up with a basic but reliable "ROM socket + FPU" card for Classic IIs (even if it were just an FPU socket instead of the actual chip), I'd buy one right away... assuming the cost were reasonable, of course. A board that small shouldn't cost too much to make even in small runs, thanks to the various prototyping services that have sprung up. I bet the worst part would be finding that weird-ass expansion-header connector for a reasonable price. Would a card like that even need any passives on the board, beyond maybe a decoupling cap or two?