Bob Blick mentioned:
> The AVR32 ... uses less power while doing the same work.

Wouter van Ooijen replied:
> references please?

Are there any better benchmarks than EEMBC?

I suspect Bob is referring to this EEMBC report, which shows that the
AVR32 uses less power than other 32-bit MCUs:

http://eembc.org/
links to
"32-bit AVR MCU/DSP Core Outperforms 32-bit MCUs by As Much As 3X in
EEMBC Benchmarks"
2006-02
http://www.atmel.com/dyn/corporate/view_detail.asp?FileName=AVR32_short_2_14.html
which seems related to
http://www.atmel.com/dyn/products/view_detail.asp?FileName=AVR32bit_long_2_14.html&family_id=682

Another suprising report I've seen recently:

"Energy Benefits of 32-bit Microprocessor Wireless Sensing Systems"
http://sensoria.com/pdf/Energy_Benefits_of_32-bit_Microprocessor_Wireless_Sensing_Systems.pdf
(Written by who? Written when?)
compares 3 benchmark programs -- CRC-32 performed byte-wise on a data
packet, FIR on 32 bit data, FFT on 16 bit data.
(written in C and compiled with gcc)
says "there are significant energy advantages to using the 32-bit
Intel PXA255 Xscale processor compared to the 8-bit ATmega128L
processor. The energy measurements showed advantages ranging from 20x
to more than 70x".

That report seems to contradict earlier reports that 8 bit processors
use less energy than 32 bit processors, such as

"8-Bitters Flourish In A 32-Bit World"
by William Wong 2002
http://www.parallax.com/dl/docs/article/8BittersWong.pdf
says
"Because 8-bit processors run slower than their larger [32-bit]
counterparts, they can consume less power to provide the same
functionality."

"Reaching down: 32-bit processors aim for 8 bits"
by Robert Cravotta 2005
http://www.edn.com/article/CA502421.html
says
"comparing published statistics of power-consumption numbers for 8-
and 32-bit processors in standby mode reveals a
two-orders-of-magnitude difference in favor of the 8-bit processors."

p.s.:
While we're comparing 8 bit vs. 32 bit processors:
What is up with the
$3.15 LPC2101FBD48-S (8 Kbyte flash memory, 2000 bytes RAM, 32-bit ARM
processor)
?
Is that price just a typo at Digikey.com ?
Or can I really buy a 32 bit ARM processor, with roughly the same
amount of Flash, RAM, and 10-bit ADC inputs, for less than the price
of a PIC16F877 or a dsPIC or most Microchip PIC18F processors?

--
David Cary
http://massmind.org/techref/member/DAV-MP-E62a/

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