Hi,

  I am unable to come across any material that critically examines the
reasons I must go in for Microblaze or Powerpc. Is processor
obsolesence the only reason why an FPGA designer would go in for
Microblaze? Could the present PowerPC architecture could become
obsolete?

Regards,
Sandy

h...@gmail.com wrote:
> Hi,
>
>   I am unable to come across any material that critically examines the
> reasons I must go in for Microblaze or Powerpc. Is processor
> obsolesence the only reason why an FPGA designer would go in for
> Microblaze?

No. To be honest, that's probably the last reason.

> Could the present PowerPC architecture could become
> obsolete?

More chance of MicroBlaze becoming obsolete first to be honest.

If you can't think of a reason why you must choose one over the other,
then it probably doesn't matter.

Cheers,
Jon

Jon,

It is true that some soft processors have become obsolete (Nios is now
Nois II).  So you have reason to doubt that another one would be successful.

However, both MicroBlaze and PicoBlaze are doing very well, azs measured
by the thousands of downloads.  Each download may be just one person
"kicking the tires" or it may be one download that gets placed in tens
of thousands of boards, we have no way to know.

We have decided that whatever we support, Power PC, MicroBlaze, or
PicoBlaze, it can not change such that old code doesn't work!  That is
the death of any processor.  Rather, all old machines may evolve, but
they must evolve in a way that allows old code to move with the changes
(similar to Intel and the x86).

A processor needs to exist, it needs an eco-system (compilers, linkers,
loaders, debuggers, etc), it needs to meet the needs (speed, power,
cost), and it needs to last the intended length of the company that
wishes to use it (it is a printer every 6 months?  or a new network
switch every three years?  or a new spacecraft once a decade?).

Many questions.  Look up the answers,

Austin

Jon Beniston wrote:
> h...@gmail.com wrote:
> 
>>  I am unable to come across any material that critically examines the
>>reasons I must go in for Microblaze or Powerpc. Is processor
>>obsolesence the only reason why an FPGA designer would go in for
>>Microblaze?
> 
> No. To be honest, that's probably the last reason.

I agree - unless you are in a super long-lifetime industry, obsolescence 
is probably a long way down the list.

> If you can't think of a reason why you must choose one over the other,
> then it probably doesn't matter.

I think it's the old favourites price and performance/features.  If you 
really need a PPC (or MGTs, or lots of DCMs, or...), then you have to be 
prepared to pay for it.  Things may change with V5, but the price 
disparity of a V4FX vs an S3/S3E is enormous.  If you can do the job 
with a MicroBlaze in a Spartan3/3E you'll save a fortune.

You can clock the PPCs faster, so in terms of raw benchmarking MIPs 
lies^H^H^H numbers it will always look superior.  But, remember there's 
an entire FPGA sitting next to it - the performance critical stuff 
should be in hardware anyway!

Earlier this year I did some back of the envelope estimates of replacing 
a mass-produced PPC single board computer with a V4FX-based solution. In 
the 1K-10K qty we could buy the entire SBC with memory and interfaces 
for about the same price as just the V4FX25 device on its own.  The need 
for FPGA fabric wasn't really there, so we didn't proceed.

John

The 2 options are good at different things.  The
way I look at is if
your task is computationally intensive, go for the PPC because you can
clock it at hundreds of MHz and run out of on-macro cache.  If the task
is basically an I/O processor and you're plugging OPB peripherals, go
with the microblaze, its faster for that kind of stuff.


h...@gmail.com wrote:
> Hi,
>
>   I am unable to come across any material that critically examines the
> reasons I must go in for Microblaze or Powerpc. Is processor
> obsolesence the only reason why an FPGA designer would go in for
> Microblaze? Could the present PowerPC architecture could become
> obsolete?
> 
> Regards,
> Sandy