> (added AVR and PIC tag -- I think it will be more like PIC vs. AVR  
> story :-))

No, not again.  Besides, multiple tags are a no-no.  (Back to just  
[avr])

>> These days I was studying the AVR Xmega MCUs for prospective use in a
>> new product. When I learned their capabilities I freaked out!

I'd be more impressed if the initial devices hadn't been over a year  
late hitting the distributers.  There have already been manufacturers  
complaining that their projects died because the chips weren't  
available in time.  Before you start using one, you might want to make  
sure that that exact chip is in-stock at SOME distributer.

>>
>> e) 4 DMA channels capable of transferring between any combination of
>> RAM/port/peripheral and the most amazing: external DMA requests  
>> available!
>>
>
> First of all, as you may know MIPS also known as Meaningless Indicator
> of Processor Speed.   [more rants about pic vs avr architecture.]

This isn't about PIC (or PIC24) vs AVR, which has long since become a  
pointless discussion.  The architectures ARE different, in ways that  
make it unclear which will perform better in any particular  
circumstance at any particular clock frequency, but they're both  
clearly quite capable of lots of things...

This is about AVR vs the new XAVR architecture.  In the latter, Atmel  
has added a lot of interesting features (DMA/etc) to the IO pieces of  
the hardware.  And lots of peripherals that are somewhat uncommon on  
microcontrollers of this size (5 or more UARTS.  Woot!)  Many are  
apparently capable of doing useful things without any CPU intervention  
at all.  The XAVRs ARE interesting...


> There are many nice thing in AVR though ,but GCC and WinAVR is not
> really one of them. The compiled code is just acceptable

Which free PIC compiler are you comparing it against?  I haven't found  
avr-gcc to be all that bad in general; some of the weirdness in  
produced code is due to those odd bits about the AVR architecture you  
mentioned (some registers not being all that "general purpose" as  
Atmel would have you believe.)

>
> with PIC architecture so overall it is faster than 8 bit AVR for sure.

Nothing is that "for sure."  If all you care about is performance, you  
can get boards with 1GHz+ x86 architectures (and a host of desktop- 
like IO) for about the same price
(~$100) as a fancy dsPIC or xAVR board.  (Thanks to mass production,  
obsolescence, and etc.  I call it "the $100 paradox")

BillW

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