RE: Repairing a SFD-1001 (8250/LP, 8050, 4040, 3040, 2040)

From: Hoffmann-Vetter, Martin <>
Date: Thu, 11 Aug 2011 15:26:07 +0200
Message-ID: <005101cc582a$3b1b5720$>
Hello Jim,

> I have been asked to run a modifed 2364 adapter that allows pin 20 to
> be inverted on non-inverted.  I used a hct86 with a jumper to ground
> on one side of the gate to alter the inversion of the line.

Okay, the 2364 has one chip select signal. So you have two states: inverted
or not.

> It looks
> like there might be value in supporting a 2332 with a similar setup.

Yes, but the 2332 has two chip select signals (see the datasheet or at
page 2-17). You can programm it via mask, so any combination are possible
(0: low aktiv, 1: high aktiv and 2: don't care). You can use both, only one
or non chip select. And all used chip select can be inverted or not.

> The 6540 adapter I have uses a hct138 to support all of the select
> lines.

Or you use a 139 (open collector) with a pullup resistor. Now you can put
one or more jumper and have a programmable wired or gate!



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Received on 2011-08-11 14:00:08

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