Reproduction micros

[Pete Turnbull]

On 20/07/2016 20:29, Paul Koning wrote:

> I don't remember the earlier ARM designs, but it was my impression
> that DEC's StrongARM was the one that made really large strides in
> low power (especially power per MHz of clock speed).  Interestingly
> enough, StrongARM was one of the few (and the first?) independent
> designs; it used the ARM architecture specification but not the
> actual logic design as others did.

That's almost right.  An ARM2 dissipates less than 2W (according to my 
data sheet, but that's maximum allowed dissipation and I think typical 
consumption is much less than 1W) with its normal 5V supply, averaging 
some 6-8 MIPS with a 12MHZ clock.  It's a 2micron CMOS process.  The 
original ARM used a 3micron process but was only used for testing and 
development; I can't remember what ARM3 used but IIRC it was a lot 
smaller though still the same core design, and it's certainly low power 
(under 1W) despite having a lot more transistors (largely for cache) and 
a higher clock speed.

StrongARM SA-110 uses roughly 450mW, but with Vcc around 1.75V it 
claimed about 100 MIPS at 100MHz, in a 0.35micron process.  It was a 
collaboration between ARM and Digital, but AIUI the hardware design was 
done mainly or perhaps completely by Digital.  Yes, it was the first 
independent design, as far as I know.  Earliest designs were done by 
Acorn and later I think by Acorn with VLSI, and ARM with Digital 
(ARM6/7).  I had access to early SA-110 development stuff for a project 
in 1996 but I had to go to Digital to get it, not Acorn/ARM.

-- 
Pete