Relay computers - test-drb@ccmp.vtda.org

24 Sep 2004

On Sep 24 2004, 15:39, Ade Vickers wrote:
...

 Additional: Hunting around for a suitable CPU to implement in relays, I
...
  came across the P8 CPU design
(http://www.rexfisher.com/P8/P8_TOC.htm).
...
  This uses a 74LS181 4-bit ALU, which I reckon would
require 149 relays to
...
  replicate. The only thing that confuzzles me is: what
use, exactly, is a
...
  1-input AND? Several of these appear on the 74LS181
schematic... 
I've not seen the specific diagram you're referring to, but are you
sure they're not NAND gates?  There are a few in the diagram I have.  A
1-input NAND is of course an inverter.  But otherwise, a 1-input gate
could be used as a buffer (there are some inverters on the LS181 inputs
for that reason) or to equalise the gate delays along some particular
path to match another.

-- 
Pete						Peter Turnbull
						Network Manager
						University of York