Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!uw-beaver!ubc-cs!alberta!calgary!ctycal!ingoldsb
From: ingoldsb@ctycal.COM (Terry Ingoldsby)
Newsgroups: comp.sys.m6809
Subject: Re: Funny key presses
Summary: 6809 speed
Message-ID: <433@ctycal.UUCP>
Date: 17 Aug 89 19:12:26 GMT
References: <430@ctycal.UUCP>
Organization: The City of Calgary, Ab
Lines: 23

In article <430@ctycal.UUCP>, ingoldsb@ctycal.COM (Terry Ingoldsby) writes:
> Has anyone fixed the keyboard driver for COCO3 OS9 Level II?  The

My apologies, that was supposed to go to comp.os.os9.

I know that there are some higher speed versions of the 6809 available.
Does anyone know if these are just fast clock speed versions of the
ordinary MC6809, or do they reduce the number of cycles for the longer
instructions.  The former is not desirable in many cases since memory
has to be faster to keep up with the chip.  Since many implementations
do the memory access in half a cycle, this can put quite a load on
memory components (ie. they have to be fast).

In some of the longer 6809 instructions memory lies idle.  A fast clocked
6809 will require fast memory that does nothing part of the time.  Not
an efficient use of resources!  On the other hand, making instructions
that spend a lot of their time doing things internally (not using the
external buses) faster would allow direct replacement of existing 6809s.
I think this was done with 8088s.
-- 
  Terry Ingoldsby                       ctycal!ingoldsb@calgary.UUCP
  Land Information Systems                           or
  The City of Calgary         ...{alberta,ubc-cs,utai}!calgary!ctycal!ingoldsb