uC versus DSP, any new trends?

Ok, folks, I did ask a similar question before but that was long ago. 
Meantime I have read articles such as one about a VoIP phone designed 
without DSP. Made me wonder: Why were they touting that absence of a DSP?

Anyway, recently I went over the DSP offerings. Again. Not much new 
stuff to write home about. Prices are still $3 and up for the low end. 
Power consumption is still high. Some will go down to a few ten uA in 
sleep or idle (well above what many uCs can do) but then they often must 
run at 50MHz or higher when awake, meaning lots of milliamps. A modern 
1.2V core doesn't make a battery application exactly easy. In the uC 
world there are powerful ARMs but they do not fare too well either in 
the consumption domain, often requiring two supply voltages. Then there 
are "more normal" 16 bitter uC with and without HW multiplier such as 
the MSP430. Almost ideal in battery apps but very low "real" clock rates 
when allowing for battery droop, and not that much horsepower to begin with.

Where does the trend go? Towards uC?

-- 
Regards, Joerg

http://www.analogconsultants.com

Joerg <notthisjoergsch@removethispacbell.net> wrote:
> Ok, folks, I did ask a similar question before but that was long ago. 
> Meantime I have read articles such as one about a VoIP phone designed 
> without DSP. Made me wonder: Why were they touting that absence of a DSP?

Single-chip solution, probably based around an ARM9 I'd guess ;)

> Where does the trend go? Towards uC?

Convergence. Devices like Blackfin, Tricore, ARM9E and PIC30 all
offer a mix of 32-bit micro and fixed-point DSP.

There'll always be tasks that demand a honking great "proper" DSP, but I
think most run-of-the-mill work will end up being done on controllers
offering the best of both worlds.

pete
-- 
pete@fenelon.com "That is enigmatic. That is textbook enigmatic..." - Dr Who
                 "There's no room for enigmas in built-up areas." - N Blackwell

Hello Pete,

> 
>>Ok, folks, I did ask a similar question before but that was long ago. 
>>Meantime I have read articles such as one about a VoIP phone designed 
>>without DSP. Made me wonder: Why were they touting that absence of a DSP?
> 
> Single-chip solution, probably based around an ARM9 I'd guess ;)
> 
>>Where does the trend go? Towards uC?
> 
> Convergence. Devices like Blackfin, Tricore, ARM9E and PIC30 all
> offer a mix of 32-bit micro and fixed-point DSP.
> 

I hope so, too. But so far it hasn't really happened. DSP are too 
expensive for many consumer apps and also too inefficient in power 
handling for battery gear. And there still seems to be a hole. It's like 
having an 8-cylinder on the DSP side and a moped on the uC side but no 
4-6 cylinders. On one app I am actually thinking about placing two 
MSP430 to handle the workload.


> There'll always be tasks that demand a honking great "proper" DSP, but I
> think most run-of-the-mill work will end up being done on controllers
> offering the best of both worlds.
> 

Microchip seems to go in that direction. But others like TI appear to be 
going another route. So far none of their 430F2xx parts comes with a HW 
multiplier, they took them away. That precludes a lot of audio DSP apps, 
it can't stomach the workload. A Blackfin would laugh about it but slurp 
up the battery in no time.

-- 
Regards, Joerg

http://www.analogconsultants.com