>>>>> "Andre" == Andre Fachat <firstname.lastname@example.org> writes: MV> Hello everyone. I spent most of christmas day soldering in my C64 MV> and since the result was quite useful I thought I'd share it with MV> the world. My I/O expander divides the D000-D7FF area into eight MV> chunks instead of the normal two giving you plenty of space for MV> hardware expansions. I uploaded the project schematics to the CBM MV> archive at funet last night, and should appear there shortly. You MV> can find it on my homepage as well, at MV> http://www.cling.gu.se/~cl3polof/IO/ Andre> Isn't there a bug in the pin description of the 74ls138? Andre> Shouldn't it be /E1, /E2 and E3? Absolutely correct. I fixed the schematic on the web page, and I'll update the archives asap. Andre> Then the logis also is ok, because the NAND (74ls00) output is Andre> low when inactive and high when active. Andre> The schematics itself (besides this) seems to be correct. Well, it works in my machine... :) Andre> Nevertheless one has to handle the Phi2 delay issue when Andre> connecting a 6522 -- but any CBM hacker should know that Andre> already... :-) Shame on me for not knowing... :) What's the phi2 delay issue? -- ___ . + . . . Per Olofsson ._|___|_, . . . . . + . . o o-o + . + MagerValp@Goth.Org . . + + + . - . . . o + . . . " + + . http://www.cling.gu.se/~cl3polof/
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