hkz

Some bodging to rectify my fuckup and...
The MiSCUSI (#Apple2 #SCSI card) works!!!

Which means that I just need some minor rerouting and I can get ready for a rev.1 release. And then for a 53C80 (MUCH easier to obtain) release too!

Apr 8 at 9:13pmWeb
Show threadhkz3d ago

The MiSCUSI and its bigger brother: the FoxSCSI by @DosFox

They're fundamentally the same card.
I have to say, I still like THT cards better for an #apple2 , but the MiSCUSI should be cheaper if someone wants it assembled in fab. Might have to look into replacing the 74LS133. It's expensive.

Show thread🇺🇦 haxadecimal 🚫👑16h ago
@hkz @DosFox
I've been sad for a long time that the 74LS133 was discontinued. It was great for Apple II cards to detect access to $CFFF to reset their expansion ROM enable flip-flop.
Show threadhkz16h ago

@brouhaha @DosFox yeah... You can use an ALS133, that seems to be still in production.
But still expensive.

And the thing that bothers me is that I did not find a solution using jellybean logic that takes less than 3 ICs.

I could use a PLD, but then we get into ridiculous territory.

Show threadDosFox8h ago

@hkz @brouhaha if you use a 74ls10 and a 74ls21, you could build an 11 input NAND, which would be enough for the apple ii SCSI card.

The apple ii is also slow enough that propagation delay might not be an issue

Show threadhkz8h ago
@DosFox @brouhaha true! I'll design a variant with that. In any case I could switch one to an 'F
Show threadDosFox8h ago
@hkz @brouhaha ah that's true! Could always knock one together on some Veroboard, and stick it into the FoxSCSI
Show threadhkz8h ago
@DosFox @brouhaha or one could tweak the cap at the output. It's there to delay the output I guess.
Show threadDosFox8h ago
@hkz @brouhaha hah of course!
Show threadzl2tod15h ago

@brouhaha

Alibaba *might* sell you small quantities of SN74LS133ML1 in an SMD package, though their listing looks almost identical to the Digikey one. Digikey will sell you 1,010 at ~30c each.

@hkz @DosFox

Show threadgloriouscow3d ago

@hkz

Seequa Corporation: Hey, you need a job?

Show threadhkz3d ago
@gloriouscow hmmm :)