Macintosh Portable SRAM card: Schematics available?

[Gorgonops]

Yay! GALs are truly magical.

 

[LaPorta]

It works! Truly

amazing to me who has no knowledge of how any of this works whatsoever!

 

[Stephen_Usher]

It's mostly electronic logic Lego really.

 

[Stephen_Usher]

Yay! GALs are truly magical.

Indeed, but most of the heavy lifting is being done by the 74HC154 to be honest. The GAL is just doing bus arbitration/flow control.

 

[LaPorta]

No matter how it works, you guys are amazing. Where did you learn all this stuff? What sort of degrees do you have?

 

[Stephen_Usher]

I just picked it up over the years. Most of it actually in the last few fixing old computers and reading up on-line, helped by Google.

My first degree is in Geology. ;-)

 

[Gorgonops]

Indeed, but most of the heavy lifting is being done by the 74HC154 to be honest. The GAL is just doing bus arbitration/flow control.

That's the important part. Isn't the GAL's fault that this board has that ridonkulous number of RAM chips. If you had fewer larger ones it'd do the job all by itself.

 

[trag]

Very nice work.  Congratulations.

 

[Gorgonops]

Where did you learn all this stuff? What sort of degrees do you have?

I had one of those Radio Shack Science Fair 150-in-1 things with the springs when I was a kid, that's probably my most relevant qualification.