Re: difference between I/O ports and memory

Ed Casas (edc@ece.ubc.ca) Wed, 6 Dec 2000 10:29:41 -0800 

Date: Wed, 6 Dec 2000 10:29:41 -0800
From: Ed Casas <edc@ece.ubc.ca>
Subject: Re: difference between I/O ports and memory



> How do we know if we are writing to memory or writing to an I/O
> port?

Address decoders look at the address bus and enable individual
I/O or memory chips.

The address the CPU puts out (based on the address supplied to
the peek() or poke() functions) and the the design of the address
decoder determine whether you are going to read (or write) to an
I/O chip or a memory chip.

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