Re: write glitch

Ed Casas (edc@ece.ubc.ca) Mon, 13 Nov 2000 15:32:18 -0800 

Date: Mon, 13 Nov 2000 15:32:18 -0800
From: Ed Casas <edc@ece.ubc.ca>
Subject: Re: write glitch



> My coputer emulatio seems to work ok until I get to instruction
> 6.  This is becuase in instruction 5 a "glitch" WRITE signal
> turns on for a very short time.  In that time the value 253 is
> written in ram[1], erasing the value '1' that was placed there
> in instruction 3.  How can I get rid of this glitch signal.

I've tried to emphasize that all your designs should be
synchronous.  This means you have only one clock driving all
flip-flops (including the ones in the RAM).

The WRITE signal is *not* a clock and a glitch on it should not
cause anything to get written.  There should be only one clock in
your design.  This clock signal's period is set long enough that
all glitches will have time to settle between rising edges.

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