Re: [openrisc] Microprocessor or Microcontroller

["Jim Dempsey" <dempsey@northnet.net>]

I've written a few operating systems for the PDP-8 minicomputer.
One can think of that as one of the grandfathers of RISC processors.
These operating systems were multi-user with real-time functionality
having user/kernel modes, networking, multiprocessors and such.
Although the PDP-8 series of computers were an assemblage of
IC's (usually 7400 series) Intercill and Harris produced this processor
as a single chip microprocessor.

If you lined up all the microprocessors, microcontrollers, microsequencers
state machines from end to end there would be no fine lines dividing them.

If I were to state which is what I would tend to say something like

    A (micro)state machine is a component of a microsequencer
    A microsequencer is a component of a microprocessor
    A microprocessor is a component of a microcontroller

Where "micro" implies an embodiement partly or in whole as an integrated
circuit (e.g. silicon). You can have state machines, sequencers, processors
and controllers using mechanical parts e.g. contacts in washing machine
timing motor or paper music rolls and vacuum lines for a player piano.

Because members of this forum are generally programming PLD's all of
these terms are abstractions. A librarian might want to classify them for
ease of reference. For this I would classify the Microcontroller as

    That which is applied to a particular purpose.
    e.g. the logic inside a Microwave Oven.

The Microprocessor being but one of components of the Microcontroller.

Off the subject

I haven't done a hardware project yet and am looking at the
Altera Excalibur (Nios) Development system. I am on a shoe-string
budget. Has anyone have anything good or bad to say about this
system?

Also, what else might I need to setup a low budget development shop
to breadboard a project. I've looked at many prototyping systems
and boards. The Altera Excalibur (Nios) Development System has
the configuration needed for development excepting for some connectors.
I was thinking about using the PMC connectors to go to a Mezzanine
breadboard daughter card. The daughter card would not be a PCI
type device. The PMC connectors has oodles of I/O pin connections
and seem better to use than the other square peg headers on the board.
Does anyone make a PMC breadboard daughter card for the connector
layout as found on this proto-typing card?

Thanks in advance

Jim Dempsey



----- Original Message -----
From: "Sam Gladstone" <samg@t-and-t.com>
To: <openrisc@opencores.org>
Sent: Thursday, November 08, 2001 8:07 PM
Subject: [openrisc] Microprocessor or Microcontroller


> Does anyone here have a idea on the classification of microprocessor vs.
> microcontroller?
> I wonder if at some point it might be prudent to separate the projects
into
> microcontrollers and
> microprocessors?  I consider microprocessors to be very general purpose
with
> advanced memory address handling, user/kernel mode and other high level
> features useful for running
> advanced operating systems. Microcontrollers, for the most part do not
need
> these features.
> A microwave SOC does not need thread control or a user/kernel mode.  I
think
> that this is
> an important distinction because it guides the design goals and feature
list
> for a processor.
>
> I welcome comments and people's experience.
>
> Regards,
>   Sam Gladstone
>
>
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