Hi
RTL is 3.6V. You could get by with CMOS but
not TTL, directly. Of course, you could run two
power rails. The signal levels of RTL and TTL are
somewhat compatable.
Dwight
From: "Cini, Richard"
<RCini(a)congressfinancial.com>
OK, this might sound like a stupid question, but being somewhat ignorant
of
RTL logic in comparison to TTL and other designs, what, if anything, can
be
substituted for RTL logic chips?
For example, if I wanted to build one of Don's devices and I wasn't
concerned with using "vintage" chips, could I do it "plug-and-play"
using
current TTL?
Rich
-----Original Message-----
From: cctalk-bounces(a)classiccmp.org
[mailto:cctalk-bounces@classiccmp.org]On Behalf Of Michael Holley
Sent: Friday, January 07, 2005 12:08 AM
To: cctalk(a)classiccmp.org
Subject: RTL Logic
I have acquired some Don Lancaster designs that use RTL logic and I am
looking for spare parts. The MC789 hex inverter is used in all of them and
I
have 2 chips. Does anyone have a reasonable source for the MC789, I can
get
all I want for $20 a chip.
I also have 2 MC799 buffers that are use in the Microlab. I have found two
each of these (MC725, MC778, MC785, MC792, MC853, MC855) that I will part
with.
SWTPC Digital Logic Microlab
http://www.swtpc.com/mholley/PopularElectronics/Apr1970/PE_Apr1970.htm
Early SWTPC keyboard
http://www.swtpc.com/mholley/PopularElectronics/Apr1974/PE_Apr1974.htm
I think that Don Lancaster's TIC TAC TOE machine from 1971 is a very
clever
design. It uses 5 ICs and 60 diodes to play the game. I may build one.
http://www.swtpc.com/mholley/RadioElectronics/Dec1971/RE_Dec1971.htm
Michael Holley
www.swtpc.com/mholley