On Mon, 03 Sep 2007 15:41:19 -0700, NickNitro
<NickHolby@googlemail.com> wrote:

>Hi,
>
>When a company chooses a CPU to be embedded, why are the typical
>choices PowerPC, ARM etc... Why not something like an AMD Athlon. On a
>similar vein to AMD processors, they seem to have embedded processors
>and the general consumer processors, why the difference? Finally,
>getting hold of the general CPUs is not an issue they're available
>everywhere, but how can a hobbyist get hold of a MIPS CPU, PowerPC CPU
>or an ARM CPU to use in a homebrew project?
>
>Many thanks,
>Nick.
>

Basically it's the cost. For instance I can get an ARM Cortex M3 for
less than US$6. Also it's very easy (relatively) to design with
embedded processors -- designing with an Athlon would lead to a very
complex PCB layout.

If you're talking about one-off homebrew, then you can't go past a
discarded PC motherboard. You'll even find them on the footpath when
people throw them out.

If you want to use an ARM (for instance), then you'll have to go to a
local distributor. The best value is to get an evaluation board but
even these aren't cheap. A STM32 (Cortex M3) Evaluation Board from
STMicroelectronics cost me US$250. It has:
- STM32 --  Cortex M3 core
- USB slave
- SD (MMC) card interface
- TFT Colour Graphics LCD
- Lots of I/O
- Simple keypad and joystick (lever)
- IAR Demo Compiler (limited to 32K) & IDE
- IAR J-Link JTAG Debugger

Alternatively you can order development boards from
http://www.olimex.com/ --- I know they're in Bulgaria. But a few
friends of mine have ordered their developments boards and are happy
with them.


+====================================+
I hate junk email. Please direct any 
genuine email to: kenlee at hotpop.com

On Sep 6, 12:48 am, Petter Gustad <newsmailco...@gustad.com> wrote:
> larwe <zwsdot...@gmail.com> writes:
> > In general you don't see many fully custom x86-based designs because
> > the only legitimate reason for designing in x86 is if you need to
> > run a GP PC OS. This means you're designing a PC. There is a great
>
> Some years ago I ported Xfree86 to an embedded PowerPC platform. The
> colors and bitmap text was all wrong due to big/little-endian
> ordering.

You should have run that PowerPC in little endian then. You are aware
of course that the PowerPC, like the ARM that came after it, can
execute in both big and little endian modes?

larwe <zwsdotcom@gmail.com> writes:

> In general you don't see many fully custom x86-based designs because
> the only legitimate reason for designing in x86 is if you need to
> run a GP PC OS. This means you're designing a PC. There is a great

Some years ago I ported Xfree86 to an embedded PowerPC platform. The
colors and bitmap text was all wrong due to big/little-endian
ordering. In theory I don't think it would have been more difficult to
design a VIA based platform than than the PowerPC one, assuming VIA
provide decent reference designs and support.

Petter
-- 
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?

larwe wrote:

> On Sep 5, 3:08 am, Petter Gustad <newsmailco...@gustad.com> wrote:
> 
> 
>>I'm aware of that, but from the local industry I don't see any designs
>>based upon VIA CPU's. I see ARM's, PowerPC, FreeScale, etc.
> 
> 
> In general you don't see many fully custom x86-based designs because
> the only legitimate reason for designing in x86 is if you need to run
> a GP PC OS. This means you're designing a PC. There is a great deal of
> domain-specific knowledge in such a task, and so it's carried out by
> specialists.
> 

Indeed, it has been awhile since I've seen new special-purpose x86
hardware, but it used to be more common, especially using the 8088 and
8086.  Examples of '386 and higher special-purpose designs include the
Netblazer routers (which most assuredly are not canonical PCs) and the
Netmon SNMP controller.

Regards,

Michael

On Sep 5, 3:08 am, Petter Gustad <newsmailco...@gustad.com> wrote:

> I'm aware of that, but from the local industry I don't see any designs
> based upon VIA CPU's. I see ARM's, PowerPC, FreeScale, etc.

In general you don't see many fully custom x86-based designs because
the only legitimate reason for designing in x86 is if you need to run
a GP PC OS. This means you're designing a PC. There is a great deal of
domain-specific knowledge in such a task, and so it's carried out by
specialists.

"slebetman@yahoo.com" <slebetman@gmail.com> writes:

> > I have several VIA mini-ITX based computers at home and I've been
> > wondering why I don't see more VIA CPU's in embedded designs?
> 
> Your experience is actually the exact reverse of reality. This is to
> be expected because the embedded world, being embedded, runs quietly
> in the background without the world noticing.

I'm aware of that, but from the local industry I don't see any designs
based upon VIA CPU's. I see ARM's, PowerPC, FreeScale, etc.

> > Don't they sell the bare CPU's and supporting chip-sets?
> >

> Typically embedded systems developers would buy them pre-soldered to
> motherboards. Even for non-x86 CPUs like the ARM or PowerPC. If you're
> looking for very small form factor motherboards (think credit card
> sized) check out Advantech.

I know that some designers/applications use mini/nano/pico-itx
motherboards in their designs, but I was thinking about the
availability of bare CPUs for design-in PCBs.

Does anybody know any ditributor in Scandinavia which carry VIA CPU's
and chipsets?

Petter
-- 
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?

NickNitro wrote:

>When a company chooses a CPU to be embedded, why are the typical
>choices PowerPC, ARM etc... Why not something like an AMD Athlon.

Imagine you are building a toy with the following attributes:

One Button

One speaker

Two aaa batteries.

Push the button, it says prase one. Push it again for 
phrase two.  Repeat until bored.

100 million units to be put on the shelves by Christmas.

Would you choose a 10 cent microcontroller or an Athlon?

-- 
Guy Macon
<http://www.guymacon.com/>

>Many people wrote:
<snip>

Thank you everybody for your informative answers. :)

Nick.

Petter Gustad wrote:

> NickNitro <NickHolby@googlemail.com> writes:
> 
> 
>>When a company chooses a CPU to be embedded, why are the typical
>>choices PowerPC, ARM etc... Why not something like an AMD Athlon. On
> 
> 
> I have several VIA mini-ITX based computers at home and I've been
> wondering why I don't see more VIA CPU's in embedded designs? Don't
> they sell the bare CPU's and supporting chip-sets?

VIA seem to be ramping their efforts in this area.
http://www.via.com.tw/en/resources/pressroom/pressrelease.jsp?press_release_no=1467

I suspect Intel are about to follow into the same power-envelope, as 
Intel recently sold off a chunk of their XScale business - the x86 stuff 
in the labs, will be more than power competitive.
Looks like something of a resurgance of x86 into embedded, as for a 
while there, they chased the GHz at all costs, and Watts were secondary.
Blade Servers, and ultra-mobile apps have pushed that along.

-jg

NickNitro wrote:
> On 4 Sep, 00:16, DJ Delorie <d...@delorie.com> wrote:
> <snip>
> 
> Thanks for the fast reply! Also, I'm curious, with RISC processors
> costing just as much and in some cases more than a PLD (such as a FPGA
> or CPLD), why don't companies go with a PLD and just get the cores
> they require?

  Because they do not actually cost 'as much, and in some cases more'.
If you do your maths right, you'll find Microcontrollers + peripherals + 
Code memory, come in cheaper than FPGA. The FPGA makes sense only
in special (lower volume) cases. Such as a special combination of 
peripherals, or a special memory mapping of HW, or FPGA as FPU etc.
  It will always be cheaper to use sandard silicon, if that silicon is
able to do the task.

-jg