Reply by Al Clark May 8, 20092009-05-08
-jg <Jim.Granville@gmail.com> wrote in news:f85bd7c4-841b-45fd-848b-
6e7db0cf36ed@a5g2000pre.googlegroups.com:

> On Mar 25, 2:11&#2013266080;am, "zhj1985" <zhanghaojun1...@hotmail.com> wrote: >> Generally, the most popular DSP archetecture which focused on complex >> digital signal processing is based on DSP +FPGA. FPGA is often used as a >> coprocessor for a DSP because those PowerPC 440 cores aren't as fast as
D
> SP >> and those algorithms which are developed by C language can be developped >> more easily than those developed by Verilog or VHDL language. >> >> However, as the time goes, FPGA has developped fast in recent years. I >> want to ask that whether those complex digital system which was based on >> DPS+FPGA can be replaced by FPGA now. And if it is, then how can I do
tha
> t? >> I know Xilinx has developed those software such as system generator, but > I >> don't know whether it can work out. Does anybody know where I can get
mor
> e >> information about those things(By the way, I use Xilinx products)?
Thanks
> . > > It's a moving target, and depends on your application, and data > bandwidths. > DSPs are falling in price, and include things you will NEVER find on a > FPGA, > like 12 bit 4MSPS ADCs > > DSPs also have the memory built in, often FLASH, and also have uA > region > power down modes, and commonly simple, single supply operation. > > So IF you can find what you need in a commercial DSP, it is always > likely to be > cheaper, and lower power, than the incremental cost of adding that to > a FPGA.. > > FPGAs come into their own, when you cannot find the 'mix' you need in > a DSP > > -jg >
I think that in most cases an FPGA & DSP are good complements. We make a dspblok module with a SHARC DSP and and a Cyclone III DSP. http://www.danvillesignal.com/dspblok/dspblok-21369+fpga-analog-devices- adsp-21369-altera-cyclone-iii-dsp-fpga-modules.html Al Clark Danville Signal Processing, Inc.
Reply by -jg May 8, 20092009-05-08
On Mar 25, 2:11=A0am, "zhj1985" <zhanghaojun1...@hotmail.com> wrote:
> Generally, the most popular DSP archetecture which focused on complex > digital signal processing is based on DSP +FPGA. FPGA is often used as a > coprocessor for a DSP because those PowerPC 440 cores aren't as fast as D=
SP
> and those algorithms which are developed by C language can be developped > more easily than those developed by Verilog or VHDL language. > > However, as the time goes, FPGA has developped fast in recent years. I > want to ask that whether those complex digital system which was based on > DPS+FPGA can be replaced by FPGA now. And if it is, then how can I do tha=
t?
> I know Xilinx has developed those software such as system generator, but =
I
> don't know whether it can work out. Does anybody know where I can get mor=
e
> information about those things(By the way, I use Xilinx products)? Thanks=
. It's a moving target, and depends on your application, and data bandwidths. DSPs are falling in price, and include things you will NEVER find on a FPGA, like 12 bit 4MSPS ADCs DSPs also have the memory built in, often FLASH, and also have uA region power down modes, and commonly simple, single supply operation. So IF you can find what you need in a commercial DSP, it is always likely to be cheaper, and lower power, than the incremental cost of adding that to a FPGA.. FPGAs come into their own, when you cannot find the 'mix' you need in a DSP -jg
Reply by glen herrmannsfeldt May 8, 20092009-05-08
Flemming@Sundance <Flemming.C@sundance.com> wrote:
 
> The argument of getting a FPGA to replace a DSP is similar to the > ?Chicken & Egg? story. Not worth having!
> I have on many occasion been involved with potential customers that > were ?sold? the idea that a FPGA could do everything and a DSP was not > needed. Similar, the DSP semiconductors suppliers, like TI, Analog > Device, etc. has been praising the level of integration that can be > found on ?Generic? DSP device and stated that a FPGA is surplus to > requirement.
If the DSP can't do everything, and you need an FPGA, and the FPGA with a soft processor can do what is needed, then the FPGA is likely a good choice.
> My general feeling is that a DSP + FPGA offers everything. The DSP is > cheap, easy to program, runs cool and offers a lot of integration,
I won't disagree, though not so obvious.
> whereas the FPGAs are expensive,
The prices are coming down pretty fast for the smaller ones.
> hard to program (compared to a processor)
Well, you can design a simple (or not so simple) processor into the FPGA and then program that. There are a few specifically designed for efficient FPGA implementation.
> but offer much faster performance, support for any kind > of I/O interface, re-programmable, etc. ? and if you really have a > high-quantity product, then you would surely want to prototype on a > DSP + FPGA, before moving to a custom ASIC device.
FPGAs offer much higher performance if you can do many operations in parallel. That is often easier in an FPGA, but it is not automatic. The actual clock rate is likely slower in the FPGA, but if you can do many more operations per clock cycle the throughput can be very high.
> A number of suppliers can be found on the Web that offers development > boards with DSP + FPGAs and a growing number of software package can > be bought that makes it possible to use Model-based design for BOTH > the FPGA and the DSP.
-- glen
Reply by Flem...@Sundance May 8, 20092009-05-08
Hi,

The argument of getting a FPGA to replace a DSP is similar to the
=93Chicken & Egg=94 story. Not worth having!

I have on many occasion been involved with potential customers that
were =91sold=92 the idea that a FPGA could do everything and a DSP was not
needed. Similar, the DSP semiconductors suppliers, like TI, Analog
Device, etc. has been praising the level of integration that can be
found on =91Generic=92 DSP device and stated that a FPGA is surplus to
requirement.

My general feeling is that a DSP + FPGA offers everything. The DSP is
cheap, easy to program, runs cool and offers a lot of integration,
whereas the FPGAs are expensive, hard to program (compared to a
processor) =96 but offer much faster performance, support for any kind
of I/O interface, re-programmable, etc. =96 and if you really have a
high-quantity product, then you would surely want to prototype on a
DSP + FPGA, before moving to a custom ASIC device.

A number of suppliers can be found on the Web that offers development
boards with DSP + FPGAs and a growing number of software package can
be bought that makes it possible to use Model-based design for BOTH
the FPGA and the DSP.

 I suggest some R&D and watching YouTube clips.

Happy reading

Rgds

Flemming Christensen


Reply by May 7, 20092009-05-07
Anybody has an idea?
Reply by Benjamin Couillard March 24, 20092009-03-24
On 24 mar, 10:11, "zhj1985" <zhanghaojun1...@hotmail.com> wrote:
> Generally, the most popular DSP archetecture which focused on complex > digital signal processing is based on DSP +FPGA. FPGA is often used as a > coprocessor for a DSP because those PowerPC 440 cores aren't as fast as DSP > and those algorithms which are developed by C language can be developped > more easily than those developed by Verilog or VHDL language. > > However, as the time goes, FPGA has developped fast in recent years. I > want to ask that whether those complex digital system which was based on > DPS+FPGA can be replaced by FPGA now. And if it is, then how can I do that? > I know Xilinx has developed those software such as system generator, but I > don't know whether it can work out. Does anybody know where I can get more > information about those things(By the way, I use Xilinx products)? Thanks.
Sure they can, it depends on your application. There are no easy answers, though. System Generator is a good tool, it's incomplete for signal processing development imo. Synplify DSP or Accel DSP are better tools (more expensive though). If your processing requirements can be met with a DSP or even a general purpose processor, I recommend you use one. If you need more power, then yes an FPGA might be better.
Reply by zhj1985 March 24, 20092009-03-24
Generally, the most popular DSP archetecture which focused on complex
digital signal processing is based on DSP +FPGA. FPGA is often used as a
coprocessor for a DSP because those PowerPC 440 cores aren't as fast as DSP
and those algorithms which are developed by C language can be developped
more easily than those developed by Verilog or VHDL language.

However, as the time goes, FPGA has developped fast in recent years. I
want to ask that whether those complex digital system which was based on
DPS+FPGA can be replaced by FPGA now. And if it is, then how can I do that?
I know Xilinx has developed those software such as system generator, but I
don't know whether it can work out. Does anybody know where I can get more
information about those things(By the way, I use Xilinx products)? Thanks.