Differences between DSP and FPGA/CPLD

[kostbill]

Hello.

I have red some threads and there are some people saying that
DSPs are more powerful in complex mathematical functions than
FPGAs, while, others say the opposite.

For example, a while ago, there was a thread for a mp3 player and
many people suggested that a DSP would be more appropriate,
can anyone explain why is that? FPGAs are not quick or powerful
enough?

Thanks.

Added after 2 hours 15 minutes:

Hello again!!!

I did not see the other post on DSP/FPGAs and that's why I post
my question.

I will just sit quit and watch the other thread.

Sorry.

 

[cedance]

Re: DSP or FPGA/CPLD

hi,

there is always a confusion between the two. i did my final year project on reconfigurable FPGAs only( not able 2 implement though). I was told that it would have been better if i had implemented on a DSP processor.

The reasons i found was that, first thing, choosing the application and the field. If there are goinf to be high degree of math, would be more related to signal processing, it s wiser to choose DSP processors the obvious reaso beeing, its was they have designed for. But if there should be a compromise for the cost at a very considerably low freqeuncy of operation, then we go for FPGA. If we could configure the architecture, then we save in terms of Area also. that ll be more advnatageous. It all depends on the application u are using. Supose u are designing the application for a medical use, u couldnt just compromise for speed.. as its very essential along with accuracy.. Its obvious abt the difficulty in implementation of complex or floating point in vhdl... and so better and efficient way would be a dsp processor and the speeds have crossed 1.2 Ghz.. so we have to choose.

hope this owuld add some light to get the answer.

/cedance

 

[shafee001]

DSP or FPGA/CPLD

hi;

DSP is for complex applications based upon digital signal processing like image processing, voice processing, recognation or compression and so on, DSP provides with built in complex mathematical functions ready to be used in your application,
FBGA is building from scratch, you have noting but your code, so it's so difficult to use it in Digital signal processing applications -even it's possible-

thanks

 

[billjoy]

DSP or FPGA/CPLD

I think the key is multiply
if your algorithm need many multipliers
choose DSP(normally DSP embedded a powerful MCU)
otherwise , choose FPGA .
because * , / always is a big problem in H/W implement , (even in FPGA) .

 

[echo47]

DSP or FPGA/CPLD

A DSP is basically a microprocessor with fast convenient multiply-accumulate and looping instructions.

Five years ago I built beamforming and image processing systems containing hundreds of DSP chips to do the required number-crunching.

Now I look back at those days and just laugh. I'm now doing four times that much processing in one FPGA chip.

 

[suryakant]

Re: DSP or FPGA/CPLD

DSP has got its dedicated hardware for signal processing functions like Transforms,

In CPLD to implement this hardware, it would take lot of Macro cells. Also depending on how much u r good at optimised coding, performance of the code will be there. So thinking of CPLD for signal processing field, I think, is bad choice.

So if u r going for signal processing or complex mathematical applications, use DSP, that will save ur time.

 

[kostbill]

Re: DSP or FPGA/CPLD

Hello.

From all you said, I get the following, that the DSP is already assinged
to do certain tasks that the FPGA cannot. This is OK, I know that,

What I am asking is if the FPGA has the power to do these things BETTER
than the DSP no matter the difficutly of the code. If we have the gates,
we can built the multipliers etc... But then of course, it is a matter of the
used frequency of the IC. DSPs operate in higher frequencies than FPGAs?
Why?

echo47 said that FPGAs are more powerful, yet in a post about an mp3
player implemented in a FPGA, amost everyone said that it could be better
with a DSP. Why?

I am sorry if I bored you.

Thank you.

 

[fpga_man]

Re: DSP or FPGA/CPLD

in fact
fpga are for architecture developpers (hardware!)
and dsp for soft developpers!

it is not the same approach!
Aniway, NOW, embedded mac in fpga make them more efficient and powerfull than dsp!
also they can do // computation, (not possible in dsp)


BUT...
you must know how to build your dsp architecture in your fpga!
You need tools and language knowlage (vhdl, verilog...)

in FPGA you can implement dsp computation AND others control inside the same chip!

 

[nemolee]

Re: DSP or FPGA/CPLD

There are several powerful FPGA now. They include embedded DSP blocks and some convenient function. If the function you'd like to use is not in it, you can built this new function by youself coding. Anyway, FPGA is good for any job. FPGA with High performance and large functions have higher unit price.

 

[echo47]

DSP or FPGA/CPLD

Take a look at this:
https://www.xilinx.com/products/virtex4/capabilities/xtremedsp.htm

I don't know what's in an MP3 player, but it doesn't require much number crunching. An old Windows computer can do it just fine. Seems like a modern FPGA would be massive overkill.

 

[irashid007]

Re: DSP or FPGA/CPLD

Well you must be knowing the concept of Software Radios these days, those are based on DSP processors and the main advantages it has is the adaptation required by todays radio, we have different standards like AMPS, GSM, CDMA etc and we require dual and tri band sets, so it is easy to configure an existing architecture on DSP for Transciever. Similarly, DSP imlementation is easier to modify whereas an FPGA desgin will require more hectic transformations. This is my personal opinion and people may disagree. But I feel that in DSP we would change few modules of a software to adapt it for other applications whereas FPGA will take more programming amendments and effort.

 

[Black Jack]

Re: DSP or FPGA/CPLD

Hi!
Read this. I think this article can help you.

"Choosing DSP or FPGA for your Application"
http://www.hunteng.co.uk/dsp-fpga.htm

-- Good Luck