Re: Lab 5 Pal Again

Ed Casas (edc@ece.ubc.ca) Thu, 16 Nov 2000 23:03:44 -0800 

Date: Thu, 16 Nov 2000 23:03:44 -0800
From: Ed Casas <edc@ece.ubc.ca>
Subject: Re: Lab 5 Pal Again



> I had better rephrase the question about pin 11 to read ...Why
> did I, as well as many others, have to hook pin 11 to ground
> (in addition to hooking pin 10 to ground)? Pleases see previous
> message same date as well as response.

Looking at the data sheet it appears that pin 11 is automatically
configured as an active-low output enable signal if you use any
registered outputs (which will be the case for this lab).

An input which is not connected (is left "floating") may be seen
as a 0 or 1 depending on the way the chip is made and other
factors.  I guess I was lucky (or unlucky, perhaps) when I did
the lab and my particular chip treated this pin as high.

You should connect pin 11 to ground to make sure your outputs are
enabled.

-- 
Ed Casas   edc@ece.ubc.ca   http://casas.ece.ubc.ca   +1 604 822-2592