7 Jan
2005
7 Jan
'05
11:51 p.m.
actually you can wire-or with diodes as long as you pay attention to the
"higher" low logic level. Naturally, the voltage is not TTL compatible, but I
have used that technique also. As for totem pole vs open collector, that is why I
mentioned reading the specs rather than getting more technical with output types. I
don't think anyone is going to whip out their TTL chips and start connecting them up
to see which one works and which one doesn't.
-----Original Message-----
From: Scott Stevens <chenmel(a)earthlink.net>
Sent: Jan 7, 2005 10:33 PM
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk(a)classiccmp.org>
Subject: Re: RTL Logic
On Fri, 7 Jan 2005 12:59:57 -0800 (PST)
Tom Jennings <tomj(a)wps.com> wrote:
On Fri, 7 Jan 2005, Steve Thatcher wrote:
Wired-OR will work fine for open-collector output TTL. It will fail
miserably with totem-pole output parts. A 'battle of the transistors'
will ensue and one output or another will win.
dirt has been known to be found in most places in
the world...
doing a wired-or and wired-and depends on reading IC specifications
for specific chips. It is what design engineers do...
Sorry for being so obtuse! Phrase meant: "wire OR/etc was very
common in RTL".
I tried wired-OR once in TTL, didn't like the results :-)