Re: How to compare computing power of microcontrollers?
- From: Grant Edwards <grante@xxxxxxxx>
- Date: Tue, 30 Aug 2005 15:55:05 -0000
On 2005-08-30, Chris Carlen <crcarleRemoveThis@xxxxxxxxxxxxxxx> wrote:
> Michael J. Noone wrote:
>> Hi - I'm trying to choose a microcontroller for a project I'm working
>> on. Originally I had been thinking about using a 20Mhz Atmel AVR, such
>> as an ATMEGA168, but I became worried about the raw computing power of
>> the AVR, as one of the main roles of this chip will be to do alot of 16
>> bit multiplication and trig at a fairly high speed. So I've been
>> looking at using an ARM - specifically the Atmel AT91SAM7A3 looks very
>> interesting to me. It's clocked 3 times as fast as the ATMEGA168, but I
>> expect that isn't a good way at all to compare it's ability to handle
>> this task to the AVR's. Is there any good way to make a comparison for
>> this application without benchmarking the chips? Thanks,
>>
>> -Michael J. Noone
>
>
> ARM is also a 32 bit CPU, vs. 8 bits for the AVR. So for instance, to
> do 32 bit arithmetic operations on AVR takes 4 instructions/clocks,
> while the ARM will do a 32 bit operation in one instruction/clock.
>
> For floating point stuff, things are more complicated, but still the
> advantage goes to the 32-bit CPU.
>
> So for 32-bit integer arithmetic anyway, a 60MHz ARM would be roughly 12
> times faster than an AVR.
At least. Rember the ARM has a barrel-shifter that can be used
in "parallel" with an arithmetic operation. IOW,
A = A + B<<3;
Is a single instruction on an ARM. If A and B are 32-bit ints,
I doubt that can be translated into to 4 AVR instructions.
--
Grant Edwards grante Yow! I just remembered
at something about a TOAD!
visi.com
.
- References:
- How to compare computing power of microcontrollers?
- From: Michael J. Noone
- Re: How to compare computing power of microcontrollers?
- From: Chris Carlen
- How to compare computing power of microcontrollers?
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