As FPGAs get cheaper and more capable, cost is no longer an issue. I can
now get an ECP2, Spartan, or Cyclone for the same price as a 21262 or C67.
Thus, IMHO when to choose one over the other.
Choose a DSP if
1) You have many different (low MIPS) algorithms to run. If the
algorithms are very different, you will have use LUTs for each individual
function, forcing a large FPGA.
2) You have control/IO code to run. If you need a TCP/IP stack or USB it
is probably easier to get a DSP to perform these functions on the side.
Otherwise, you will probably have to add a processor to support this stuff.
Choose an FPGA if
1) You have a small number of high MIPS algorithms to run.
2) You don't need any control/IO, or you already have an independent
processor to perform these functions.
Remember, that the MIPs of an algorithm is based on the sampling rate of
the data. An 8192 pt FFT doesn't take much processing power if the
points
are sampled at a 1 sec rate.
Good luck programming the C67. I lost all my hair doing assembly language
on the C67, with it's fully exposed variable length pipeline (just on
the
instructions that are in the C67 and not in the C62).
FPGA vs DSP
Started by ●October 12, 2007
Reply by ●October 16, 20072007-10-16
I suspect that if you took a particular algorithm implemented it on a DSP
and in an FPGA, you will find that the power consumption is similar.
However, both of them have much higher power consumption then an ASIC,
which is why alot of the functionality in a cell phone is implemented with
ASICs.
That being said, alot of places using ASICs, cell phone or otherwise, use
FPGAs for development and then make an ASIC when their RTL has been tested
in the FPGA.
FPGAs are not going to supplant DSPs, but some designs that in the past
would be done with DSPs may in the future be implemented in FPGAs instead.
This is why I had wrote down reasons for using one or the other.
Dan
mouli
com> cc:
Subject: Re: [fpgadsp] FPGA vs DSP
10/13/2007 05:51
PM
hi daniel,
I have a small query, as in even if the cost of FPGAs is less do you notice
FPGAs penetrating into the endproducts and replacing the DSPs(i guess power
dissipation might be issue). I mean i just am looking at the future of
FPGAs(not just being used for prototyping the ASIC design functionality) as
replacement of DSPs.
I have worked on some Ti dsps. C55x, DM270, DM320. Then felt i had enough
of assembly coding and came to college to do some RTL design. But I am a
bit concerned if its a logically correct step and am i in sync with the
technological developments.
BDTI seems to be claiming the prominence of FPGAs. but I am not yet
convinced if an FPGA can replace programmable DSP processors in a low power
DSP devices like ... Cellphones...
regards
mouli.
On 10/12/07, d...@mksinst.com
wrote:
As FPGAs get cheaper and more capable, cost is no longer an issue. I can
now get an ECP2, Spartan, or Cyclone for the same price as a 21262 or C67.
Thus, IMHO when to choose one over the other.
Choose a DSP if
1) You have many different (low MIPS) algorithms to run. If the
algorithms are very different, you will have use LUTs for each individual
function, forcing a large FPGA.
2) You have control/IO code to run. If you need a TCP/IP stack or USB it
is probably easier to get a DSP to perform these functions on the side.
Otherwise, you will probably have to add a processor to support this stuff.
Choose an FPGA if
1) You have a small number of high MIPS algorithms to run.
2) You don't need any control/IO, or you already have an independent
processor to perform these functions.
Remember, that the MIPs of an algorithm is based on the sampling rate of
the data. An 8192 pt FFT doesn't take much processing power if the points
are sampled at a 1 sec rate.
Good luck programming the C67. I lost all my hair doing assembly language
on the C67, with it's fully exposed variable length pipeline (just on the
instructions that are in the C67 and not in the C62).
--
To save the world is the simplest thing in the world. All one has to do is
think. Leonard Peikoff
vijay chandra mouli N.
ECE department,
NC state univeristy,
Raleigh,NC-27606.
and in an FPGA, you will find that the power consumption is similar.
However, both of them have much higher power consumption then an ASIC,
which is why alot of the functionality in a cell phone is implemented with
ASICs.
That being said, alot of places using ASICs, cell phone or otherwise, use
FPGAs for development and then make an ASIC when their RTL has been tested
in the FPGA.
FPGAs are not going to supplant DSPs, but some designs that in the past
would be done with DSPs may in the future be implemented in FPGAs instead.
This is why I had wrote down reasons for using one or the other.
Dan
mouli
com> cc:
Subject: Re: [fpgadsp] FPGA vs DSP
10/13/2007 05:51
PM
hi daniel,
I have a small query, as in even if the cost of FPGAs is less do you notice
FPGAs penetrating into the endproducts and replacing the DSPs(i guess power
dissipation might be issue). I mean i just am looking at the future of
FPGAs(not just being used for prototyping the ASIC design functionality) as
replacement of DSPs.
I have worked on some Ti dsps. C55x, DM270, DM320. Then felt i had enough
of assembly coding and came to college to do some RTL design. But I am a
bit concerned if its a logically correct step and am i in sync with the
technological developments.
BDTI seems to be claiming the prominence of FPGAs. but I am not yet
convinced if an FPGA can replace programmable DSP processors in a low power
DSP devices like ... Cellphones...
regards
mouli.
On 10/12/07, d...@mksinst.com
wrote:
As FPGAs get cheaper and more capable, cost is no longer an issue. I can
now get an ECP2, Spartan, or Cyclone for the same price as a 21262 or C67.
Thus, IMHO when to choose one over the other.
Choose a DSP if
1) You have many different (low MIPS) algorithms to run. If the
algorithms are very different, you will have use LUTs for each individual
function, forcing a large FPGA.
2) You have control/IO code to run. If you need a TCP/IP stack or USB it
is probably easier to get a DSP to perform these functions on the side.
Otherwise, you will probably have to add a processor to support this stuff.
Choose an FPGA if
1) You have a small number of high MIPS algorithms to run.
2) You don't need any control/IO, or you already have an independent
processor to perform these functions.
Remember, that the MIPs of an algorithm is based on the sampling rate of
the data. An 8192 pt FFT doesn't take much processing power if the points
are sampled at a 1 sec rate.
Good luck programming the C67. I lost all my hair doing assembly language
on the C67, with it's fully exposed variable length pipeline (just on the
instructions that are in the C67 and not in the C62).
--
To save the world is the simplest thing in the world. All one has to do is
think. Leonard Peikoff
vijay chandra mouli N.
ECE department,
NC state univeristy,
Raleigh,NC-27606.
Reply by ●December 28, 20072007-12-28
Hai,
Your write up isinteresting and thought provoking.Have you done some work in Wireless areas using FPGA/VHDL xilik soft ware.any thing interesting to read or work with.I started gathering as I am teaching cellular and mobile communications this semester
>As FPGAs get cheaper and more capable, cost is no longer an issue. I can
>now get an ECP2, Spartan, or Cyclone for the same price as a 21262 or C67.
>
>Thus, IMHO when to choose one over the other.
>
>Choose a DSP if
>1) You have many different (low MIPS) algorithms to run. If the
>algorithms are very different, you will have use LUTs for each individual
>function, forcing a large FPGA.
>2) You have control/IO code to run. If you need a TCP/IP stack or USB it
>is probably easier to get a DSP to perform these functions on the side.
>Otherwise, you will probably have to add a processor to support this stuff.
>
>Choose an FPGA if
>1) You have a small number of high MIPS algorithms to run.
>2) You don't need any control/IO, or you already have an independent
>processor to perform these functions.
>Remember, that the MIPs of an algorithm is based on the sampling rate of
>the data. An 8192 pt FFT doesn't take much processing power if the points
>are sampled at a 1 sec rate.
>
>Good luck programming the C67. I lost all my hair doing assembly language
>on the C67, with it's fully exposed variable length pipeline (just on the
>instructions that are in the C67 and not in the C62).
>
Your write up isinteresting and thought provoking.Have you done some work in Wireless areas using FPGA/VHDL xilik soft ware.any thing interesting to read or work with.I started gathering as I am teaching cellular and mobile communications this semester
>As FPGAs get cheaper and more capable, cost is no longer an issue. I can
>now get an ECP2, Spartan, or Cyclone for the same price as a 21262 or C67.
>
>Thus, IMHO when to choose one over the other.
>
>Choose a DSP if
>1) You have many different (low MIPS) algorithms to run. If the
>algorithms are very different, you will have use LUTs for each individual
>function, forcing a large FPGA.
>2) You have control/IO code to run. If you need a TCP/IP stack or USB it
>is probably easier to get a DSP to perform these functions on the side.
>Otherwise, you will probably have to add a processor to support this stuff.
>
>Choose an FPGA if
>1) You have a small number of high MIPS algorithms to run.
>2) You don't need any control/IO, or you already have an independent
>processor to perform these functions.
>Remember, that the MIPs of an algorithm is based on the sampling rate of
>the data. An 8192 pt FFT doesn't take much processing power if the points
>are sampled at a 1 sec rate.
>
>Good luck programming the C67. I lost all my hair doing assembly language
>on the C67, with it's fully exposed variable length pipeline (just on the
>instructions that are in the C67 and not in the C62).
>
