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Contributor
Contributor
7,433 Views
Registered: ‎05-17-2009

why use a processor based system

hi all,

 

can you please give some sound reasons for using a processor based system. i mean that i have seen some people that have entire design written in verilog without using any processor. so if all that cna be done why should we shift to processor based design because we are comprimisng on performance in a way that we have shifted from parrallel to sequential execution. please do help

 

 

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7 Replies
7,409 Views
Registered: ‎08-21-2008

Re: why use a processor based system

Hello.

One of the answer to your question can be like this.

You must have implemented a simple counter in VHDL but have you ever seen its RTL level block. Have a look at it.

the use of processor reduces the complexity.

Also If there are interrupts then you cannot handle them in VHD. It will be very difficult.

You cannot do multi-threading in VHD which is very important aspect.

Also you cannot use Operating system to handle multi-threading.

In bigger applications you need to have a processor to reduce complexity.

Count <= Count+1; in VHD and count=count+1; in C are highly different.

Guess what could have been the size of your motherboard had there been no INTEL processors in the existing world.

Message Edited by prateek_bhatt on 10-05-2009 02:44 AM
Best of luck.
--
Unlimited in my Limits.
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7,399 Views
Registered: ‎07-15-2008

Re: why use a processor based system

Sure,

 

it’s all about accessibility and flexibility………

 

 How many competent VHDL engineers do you know?

 

Ok now how many competent software engineers do you know?

 

Now how many competent microprocessor engineers do you know?

 

An FPGA engineer that uses VHDL is much like the guy who designs microprocessors. It’s all about circuit design.

 

Again how many software engineers do you know?

 

Xilinx are building an excellent “hardware operating system” much like Microsoft built an excellent operating system for the x86 (lol I remember it and couldn’t see the point at the time)…..

 

I see the point now!

 

 

 Intel will go down the pan, tomorrows technology leader will be the re-configurable logic manufacturer. Xilinx has taken the approach that the majorities get cheap almost free technology, this make their insanely complex devices accessible.

 

Why use a processor based system???? because someone else has done the hard work so that you’ll buy their silicon. And because everyone is buying their silicon they can get the price down, so now even more people buy their silicon

 

Altera caught onto this idea a little later, that’s why Xilinx is in the lead right now. If these two giants put their heads together, well you can forget the 286, 386, 486, 486-dx, the 486-dx2, PI, PII, PIII PIV, PIV-HT (which was cool) the multi core and the 64 yadi ya it will be the XA-1.

 

 Doubting this will happen I’ll put money on the Xilinx-1 and the age of re-configurable computing just as soon as the Xilinx hardware OS (for want of a better expression) is truly embraced..

 

All Xilinx need to do now is drop petalogic and develop an actual free software OS that will make their devices truly accessible to the software community. Linux and petalogic simply don’t mix, they did once because once it was freely available. Either that or exceptional quality at a very very very low cost, peta don’t offer this!

 

 

Bob

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Historian
Historian
7,390 Views
Registered: ‎02-25-2008

Re: why use a processor based system


ahs23 wrote:

hi all,

 

can you please give some sound reasons for using a processor based system. i mean that i have seen some people that have entire design written in verilog without using any processor. so if all that cna be done why should we shift to processor based design because we are comprimisng on performance in a way that we have shifted from parrallel to sequential execution. please do help

 

 


Some applications make more sense done using a traditional sequential-execution microprocessor.

 

Some make more sense done using application-specific logic, however it might be implemented.

 

The engineer must understand the pros and cons of each and choose the best implementation for the problem at hand.

----------------------------Yes, I do this for a living.
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Explorer
Explorer
7,370 Views
Registered: ‎04-06-2009

Re: why use a processor based system

 

Well explained by Bob/Prateek/Bassman. Especially Bob has explained using good examples.

 

In few words I just want to say one decade back FPGA was not that popular....And most of the design were Processor based. Say today some one asks to redesign the same in limited time frame where one focus is t reduce the board size - The best answer to me is to use Embedded system inside the FPGA. Use the Processor Core - Reuse the firmware written in C as it is already tested functionally -Make your own Peripherals using HDL - Or one may use a standard IP available in the market - Just do the fine tuning required in the firmware - Do the testing and validation - And your design is ready. 

 

Prateek has given an example of Counter. To visualize it more easily I'll prefer to give the example of a Serial Communication using UART. It is more easy to write a code in C for serial communication using a standard structure like Header/Packet Length/Body/Footer and much more flexible. So just write the HDl Code for UART or use the IP of UART with the Processor core and write the firmware of serial communication according to your requirement and preferably as a Interrupt Service Routine.

 

The best part of using Embedded system inside the FPGA is parallelism. Also the best part is, you can use your own Hardware Accelerator short of things. Say you need to do some Multiplication - you can make your peripherals using dedicated multiplier which will independently perform the multiplication and pass on the product value to the processor  - hence reducing the overhead of the processor.

 

According to me try make your design as simple as you can and hats of to the FPGA as it has given us that platform.

Shantanu Sarkar
http://www.linkedin.com/pub/shantanu-sarkar/0/33a/335
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Contributor
Contributor
7,338 Views
Registered: ‎06-12-2009

Re: why use a processor based system

My last couple of projects were fairly big VHDL-only designs that did signal processing and message parsing, no CPU.  My current design uses the MicroBlaze for message parsing in C, and does signal processing in a couple of custom VHDL peripherals.

 

I am a fan of the VHDL-only approach because of the complexities in integrating CPU / peripherals. And everything is in one language so I do not have to go back and forth between C and VHDL.  And need to use only one tool, like ISE.

 

But I have found the MicroBlaze approach has a few advanteges -

  - The CPU is a better fit for sequential nature of message parsing 

  - It is easier to write and understand C code for message parsing

  - It is faster to re-build C code and start debug, like 30 seconds versus 15 minutes

  - Probably more engineers know C than VHDL/Verilog so code may be easier to maintain

 

Jim

 

 

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Highlighted
7,249 Views
Registered: ‎10-21-2009

Re: why use a processor based system

Hello Bob,

bobster_the_lobster wrote:

 

All Xilinx need to do now is drop petalogic and develop an actual free software OS that will make their devices truly accessible to the software community. Linux and petalogic simply don’t mix, they did once because once it was freely available. Either that or exceptional quality at a very very very low cost, peta don’t offer this!

 


It's John Williams here, PetaLogix CEO/CTO.

 

Can you explain a little further your comments?  You can go to www.petalogix.com today and download PetaLinux, without paying a cent, as you have been able to do for many years now. 

 

We do require a valid, non-"webmail" email address for registration, because we think that it's reasonable we know who our users are.  If you don't like that condition, then you are free to roll your own Linux solution based on the mainline Linux kernel sources (MicroBlaze pushed to the public trees by PetaLogix BTW), the Xilinx toolchain source package download, then grab busybox, write some root filesystem builder scripts, then test and validate it, and off you go. 

 

Or, you could use PetaLinux, and instead spend your time building great products.

 

When I was last at Xilinx I continued my lobbying from the CTO down, to actively embrace open source and start pushing all of the GNU sources to mainline repositories, and there has been significant progress on that front since then.  PetaLogix did it with the kernel, the GCC tools are on their way to the FSF mainline trees, and so on.

 

Vendors exist because they add value (if they don't, they won't be around for long).  I believe that PetaLogix has added, and continues to add, tremendous value around what is available for free for Linux on MicroBlaze. So too, apparently, do thousands of our users, worldwide across all industries and sectors.

 

Regards,

 

John

 

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Explorer
Explorer
7,224 Views
Registered: ‎04-06-2009

Re: why use a processor based system

One good news for we all........ 

 

XILINX AND ARM ANNOUNCE DEVELOPMENT COLLABORATION

 

 

Shantanu Sarkar
http://www.linkedin.com/pub/shantanu-sarkar/0/33a/335
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