I am faced with selecting a replacement processor/uC for a re-design of 
some industrial controller/safety equipment. The technical requirements 
can be satisfied by just about any 32bit risc style uP/uC, but one key 
requirement is that since the product life is decades long, the 
particular part or at least the architecture should continue to be 
supported by the vendor for as long as possible.

This seems a pretty tough requirement. Years ago, the x86 would have 
been a good choice, but probably not today. I also think this pretty 
much rules out any Microchip or Atmel parts as their 32bit line is too 
new and they have already obsoleted their earliest parts. The latest 
architectures may be too new to say anything about longevity. I am 
leaning towards the ARM architecture or perhaps MIPs - something that 
already has a very large installed base to guarantee continued support. 
Thoughts?

On Sat, 05 Jul 2008 23:15:21 -0700, tns1 <t...@cox.net> wrote:

>I am faced with selecting a replacement processor/uC for a re-design of 
>some industrial controller/safety equipment. The technical requirements 
>can be satisfied by just about any 32bit risc style uP/uC, but one key 
>requirement is that since the product life is decades long, the 
>particular part or at least the architecture should continue to be 
>supported by the vendor for as long as possible.
>
>This seems a pretty tough requirement. Years ago, the x86 would have 
>been a good choice, but probably not today. I also think this pretty 
>much rules out any Microchip or Atmel parts as their 32bit line is too 
>new and they have already obsoleted their earliest parts. The latest 
>architectures may be too new to say anything about longevity. I am 
>leaning towards the ARM architecture or perhaps MIPs - something that 
>already has a very large installed base to guarantee continued support. 
>Thoughts?

You probably won't be able to secure the kind of stability in actual
or simulated (ASIC) hardware environments that surround the processor,
as the x86 received driven by 'compatibility' pressures of the market,
anywhere else.  But in terms of software tools used to develop the
code, the ARM7TDMI as a core has fairly broad support across a number
of vendors and is likely to continue for a while.  Peripherals will
vary, of course, and so will the memory environments and methods for
controlling all this... but the tools you use now will probably work
satisfactorily on ARM7TDMI processors a decade or two from now, with
appropriate changes in code support for peripheral differences you
won't be able to entirely avoid.

I like MIPS more than ARM7 instructions, perhaps because of having a
longer history with them (1987) if nothing else, but I suspect ARM7 is
a better gamble.

But I'm interested in hearing responses, too.

Jon

>  But in terms of software tools used to develop the
> code, the ARM7TDMI as a core has fairly broad support across a number
> of vendors and is likely to continue for a while.  Peripherals will
> vary, of course, and so will the memory environments and methods for
> controlling all this... but the tools you use now will probably work
> satisfactorily on ARM7TDMI processors a decade or two from now, with
> appropriate changes in code support for peripheral differences you
> won't be able to entirely avoid.

On the assumption your ARM7 tools also support the ARM Cortex-M3....

If you are worried about future support consider a lifetime buy of the 
components.

--
Regards,
Richard.

+ http://www.FreeRTOS.org & http://www.FreeRTOS.org/shop
17 official architecture ports, more than 6000 downloads per month.

+ http://www.SafeRTOS.com
Certified by TÜV as meeting the requirements for safety related systems.

On Sun, 06 Jul 2008 07:36:43 GMT, "FreeRTOS.org" <n...@given.com>
wrote:

><snip>
>If you are worried about future support consider a lifetime buy of the 
>components.

That isn't so easy.  Often, there are many specific parts involved,
incoming testing requirements suddenly bunched all at once, long term
storage/shrinkage issues, etc.  So there are risks in all directions.

Luckily, I'm not so concerned but I am still curious about tradeoffs.
Even if one accepts the idea that nothing remains the same for long in
this business, there is an advantage thinking about holding the
software tool chain as static when supporting products that may need
continued production and support long into the future, even if
everything else changes around it.

Jon

> Even if one accepts the idea that nothing remains the same for long in
> this business, there is an advantage thinking about holding the
> software tool chain as static when supporting products that may need
> continued production and support long into the future, even if
> everything else changes around it.

We have some long term support requirements where not only have we archived 
copies of development tools and the version of Windows used to build the 
software (this is already obsolete) but also entire PC systems on the 
assumption that the hardware on which this version of Windows is capable of 
running will also be obsolete.

--
Regards,
Richard.

+ http://www.FreeRTOS.org & http://www.FreeRTOS.org/shop
17 official architecture ports, more than 6000 downloads per month.

+ http://www.SafeRTOS.com
Certified by TÜV as meeting the requirements for safety related systems. 

tns1 wrote:
> I am faced with selecting a replacement processor/uC for a re-design of 
> some industrial controller/safety equipment. The technical requirements 
> can be satisfied by just about any 32bit risc style uP/uC, but one key 
> requirement is that since the product life is decades long, the 
> particular part or at least the architecture should continue to be 
> supported by the vendor for as long as possible.
> 
> This seems a pretty tough requirement. Years ago, the x86 would have 
> been a good choice, but probably not today.

Why not ?  PC104 and variants are long life, and the new Intel Atom
runs x86 code fine.
You can expect the form factor to change quite quickly on x86, but the
code base/software is very stable.
Another advantage, is the tools can be Native, not cross-tools.

You could even archive the Tools.Compiler.Build INSIDE each shipped
unit :)

> I also think this pretty 
> much rules out any Microchip or Atmel parts as their 32bit line is too 
> new and they have already obsoleted their earliest parts. The latest 
> architectures may be too new to say anything about longevity.

You seem to be confusing architecture with device: to be fully SW binary 
compatible, the 'Architecture' umbrella has to include peripherals and 
pinouts. As soon as you lose that, you have to recompile and redesign
parts of the system.

> I am 
> leaning towards the ARM architecture or perhaps MIPs - something that 
> already has a very large installed base to guarantee continued support. 
> Thoughts?

How many Decades, exactly ?
You are right that is a tough call. Even ARM7 is now 'trailing edge',
and tagged 'not for new designs' - they have moved on to Cortex M3.

How long will the Cortex M3 last ?

If you want field-longevity, one way is to design at the PCB level,
for replacement. Very like the PC104 system does.
USB is another physical standard, that will have very long legs.

That also means you are not stuck with a truly ancient system
in 15 years time.

How important is price, and power consumption ?

-jg

On Sat, 05 Jul 2008 23:15:21 -0700, tns1 <t...@cox.net> wrote:

>I am faced with selecting a replacement processor/uC for a re-design of 
>some industrial controller/safety equipment. The technical requirements 
>can be satisfied by just about any 32bit risc style uP/uC, but one key 
>requirement is that since the product life is decades long, the 
>particular part or at least the architecture should continue to be 
>supported by the vendor for as long as possible.

You might consider using softcores in FPGAs. That means that the cpu and all
peripherials are coded in VHDL or Verilog and compiled into logic that can
be loaded into an FPGA. If a silicon gets unavailable, you just recompile
your source for another one. Ok, it'll be a bit more work than just
recompiling, but much less then changing the system architecture.

Mit freundlichen Grüßen

Frank-Christian Krügel

tns1 wrote:
> I am faced with selecting a replacement processor/uC for a re-design of 
> some industrial controller/safety equipment. The technical requirements 
> can be satisfied by just about any 32bit risc style uP/uC, but one key 
> requirement is that since the product life is decades long, the 
> particular part or at least the architecture should continue to be 
> supported by the vendor for as long as possible.
> 
> This seems a pretty tough requirement. Years ago, the x86 would have 
> been a good choice, but probably not today. I also think this pretty 
> much rules out any Microchip or Atmel parts as their 32bit line is too 
> new and they have already obsoleted their earliest parts. The latest 
> architectures may be too new to say anything about longevity. I am 
> leaning towards the ARM architecture or perhaps MIPs - something that 
> already has a very large installed base to guarantee continued support. 
> Thoughts?

Motorola/FreeScale has a good reputation for the parts longevity as well 
as the reliability. The ColdFire will probably last for quite some time; 
  MPC family could be the choice also.


Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com

Jonathan Kirwan wrote:
> On Sun, 06 Jul 2008 07:36:43 GMT, "FreeRTOS.org" <n...@given.com>
> wrote:
> 
>> <snip>
>> If you are worried about future support consider a lifetime buy of the 
>> components.
> 
> That isn't so easy.  Often, there are many specific parts involved,
> incoming testing requirements suddenly bunched all at once, long term
> storage/shrinkage issues, etc.  So there are risks in all directions.

Automotive companies are good at it- the airbag ECU, for example, has to 
be serviceable in 15 years or so. And you have to have exactly the same 
unit because of software dependency on car frame characteristics etc. 
As far, as my memory serves, they use ARM7. If you *really* want a part, 
that will be around in 15 years, go for automotive. They might be not 
the fanciest parts, though.

M.W.

On 6 Jul, 07:15, tns1 <t...@cox.net> wrote:
> I am faced with selecting a replacement processor/uC for a re-design of
> some industrial controller/safety equipment. The technical requirements
> can be satisfied by just about any 32bit risc style uP/uC, but one key
> requirement is that since the product life is decades long, the
> particular part or at least the architecture should continue to be
> supported by the vendor for as long as possible.
>
> This seems a pretty tough requirement. Years ago, the x86 would have
> been a good choice, but probably not today. I also think this pretty
> much rules out any Microchip or Atmel parts as their 32bit line is too
> new and they have already obsoleted their earliest parts. The latest
> architectures may be too new to say anything about longevity. I am
> leaning towards the ARM architecture or perhaps MIPs - something that
> already has a very large installed base to guarantee continued support.
> Thoughts?

Microchip tends to keep parts in production. The new PIC32 (MIPS core)
might be a good choice.

Leon