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Macintosh Portable Card ID

Posted by: Canby Fat Mac on 2017-02-28 21:32:58 Came across this card inside a 5120. Can't find much of anything online about it. Anyone know what it is?

Posted by: rsolberg on 2017-02-28 22:49:51 It's a RAM expansion card. Those eight parallel black components are the RAM ICs. They're in the fairly unusual ZIP (rather than DIP) packaging. I recognized that much, and a search for "Macintosh Portable"+Xilinx yielded this: https://www.reddit.com/r/VintageApple/comments/4scwil/got_4_macintosh_portables_for_100_what_is_this/

Posted by: techknight on 2017-03-01 05:24:06 Would be cool if that xilinx chip was readable. as that is acting not only as an address decoder, but an SRAM to DRAM converter, as DRAM is muuuuch cheaper than SRAM these days. The 1Mhz crystal serves as the refresh clock.

Posted by: rsolberg on 2017-03-01 15:41:49 That's pretty slick. The 3020 was a pretty common FPGA for a number of years, so I imagine there's development boards and software out there somewhere.

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