SOC vs. Microcontroller vs. Microprocessor

I have always liked to distinguish a microprocessor from a
microcontroller based on whether or not there are integrated
peripherals on the same chip or just a CPU. There are some companies
that seem to refer to what I traditionally thought of as
microcontrollers by the term du jour, System-on-a-Chip. Are these two
terms synonymous? Furthermore, sometimes these SOCs are referred to in
the same documentation as processors. Isn't this a bit imprecise, and
wouldn't calling them microcontrollers be better since they are a
processor + a bunch of integrated peripherals and memories?

Thanks.

In article <1181441274.468076.40490@w5g2000hsg.googlegroups.com>, joshc 
says...
> I have always liked to distinguish a microprocessor from a
> microcontroller based on whether or not there are integrated
> peripherals on the same chip or just a CPU. There are some companies
> that seem to refer to what I traditionally thought of as
> microcontrollers by the term du jour, System-on-a-Chip. Are these two
> terms synonymous? Furthermore, sometimes these SOCs are referred to in
> the same documentation as processors. Isn't this a bit imprecise, and
> wouldn't calling them microcontrollers be better since they are a
> processor + a bunch of integrated peripherals and memories?

I think you are expecting a precision in the language that just isn't 
there.  All definitions three terms have as much to do with marketing as 
real distinctions, and the distinctions were not that cut and dried to 
begin with.

Although I do expect a spate of definitions to pop up with a theological 
discussion on how many  micros can dance on the head of a pin now ;)

BTW the distinction I always heard between microcontroller and 
microprocessor was the microcontroller did not have an external bus and 
the microprocessor did.

SOC seems to be, or have quickly become, almost entirely a marketing 
term from what I can see.  

Robert

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On Jun 9, 7:07 pm, joshc <josh.cu...@gmail.com> wrote:
> I have always liked to distinguish a microprocessor from a
> microcontroller based on whether or not there are integrated
> peripherals on the same chip or just a CPU. There are some companies
> that seem to refer to what I traditionally thought of as
> microcontrollers by the term du jour, System-on-a-Chip. Are these two
> terms synonymous? Furthermore, sometimes these SOCs are referred to in
> the same documentation as processors. Isn't this a bit imprecise, and
> wouldn't calling them microcontrollers be better since they are a
> processor + a bunch of integrated peripherals and memories?
>
> Thanks.

SOC are more integrated then microcontrollers (e.g., the portalplayers
are a good example) multi cpu's, built in charge pumps (multi
regulators), specialized media processors, integration of different
dies for analog and digital (DAC+ audio amps for headphones), built in
Li-Ion chargers, none of which are seen in your standard
microcontrollers.

Robert Adsett wrote:

> BTW the distinction I always heard between microcontroller and 
> microprocessor was the microcontroller did not have an external bus and 
> the microprocessor did.

Which of course makes a dog's ear out of any chip that can be configured 
to either have one or not.

In article <f4hq72$5jf$03$4@news.t-online.com>, Hans-Bernhard Br&#4294967295;ker 
says...
> Robert Adsett wrote:
> 
> > BTW the distinction I always heard between microcontroller and 
> > microprocessor was the microcontroller did not have an external bus and 
> > the microprocessor did.
> 
> Which of course makes a dog's ear out of any chip that can be configured 
> to either have one or not.
> 

Yep, or at least of the definition.  I'm clearly not the only one used 
to that distinction though.

http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=
1406&dDocName=en027867

http://people.msoe.edu/~welch/courses/cs391/cs391-02.pdf

Which brings us back to pin heads which seems to have sparked an 
unexpected chord.

Robert

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On Sun, 10 Jun 2007 02:07:54 -0000, joshc <josh.curtz@gmail.com>
wrote:

>I have always liked to distinguish a microprocessor from a
>microcontroller based on whether or not there are integrated
>peripherals on the same chip or just a CPU. There are some companies
>that seem to refer to what I traditionally thought of as
>microcontrollers by the term du jour, System-on-a-Chip. Are these two
>terms synonymous? Furthermore, sometimes these SOCs are referred to in
>the same documentation as processors. Isn't this a bit imprecise, and
>wouldn't calling them microcontrollers be better since they are a
>processor + a bunch of integrated peripherals and memories?
>
>Thanks.

Whilst i do like wine, I musch prefer beer. Sometimes i drink cider
too. I guess the are all the same.