RTL Logic

From: Steve Thatcher <melamy_at_earthlink.net>
Date: Sat Jan 8 07:51:45 2005

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_at_earthlink.net>
Sent: Jan 7, 2005 10:33 PM
To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk_at_classiccmp.org>
Subject: Re: RTL Logic

On Fri, 7 Jan 2005 12:59:57 -0800 (PST)
Tom Jennings <tomj_at_wps.com> wrote:

> On Fri, 7 Jan 2005, Steve Thatcher wrote:
> > 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 :-)

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.
Received on Sat Jan 08 2005 - 07:51:45 GMT

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:37:43 BST