How to choose the best FPGA chip?

[Z80]

best fpga

Hello

I'm facing this problem. I'm new to FPGA, learned some Verilog so I can get going, but now I don't know how to choose the right chip. There is Altera, Xilinx, and who knows what else, and each have such a broad range of chips, with so wide ranges of prices and it is confusing for a newbie. I want to build a chip that will incorporate an ATA controller beside other things. After considering the idea of using a TI DSP because I need speed I thought that it doesn't make too much sense to use such a complex chip only because I need speed, because I don't need a very complex arithmetic core, I will only do multiplications in the worst case, and I won't need to perform them fast, not to mention that the learning curve with DSP's, especially the ones from TI, is kinda steep, at least so I've been told.
The next option is FPGA but how do I know what chip will have enough gates and speed?

Please tell me, how do you solve this problem? How do you choose your FPGA chip when faced with a new project?

 

[farhada]

choosing an fpga

Hi,
First of all, if you want to access ATA device, then you need some sofisticated program to access the informaiton, to understand the file format etc. For that, I think FPGA's are not that good.

If price is an issue for you, I would look into a smal 8-bit u-controller+FPGA to make your design small and cheap. Even using an internal soft-core CPU can makes thing easier than trying to have full ATA support in Verilog or VHDL.

Anyway, it all depends on what you want to do, how much space do you need, your budget for this prject and how much the end product should cost!

Anyway, choosing the FPGA depends highly on your special needs, with todays prices and amazing large sizes of FPGAs, they are very attractive and can be used in many different ways. And a lot of times, it is a matter of taste to choose between Altera and Xilinx.

On the side of these ideas, if you do not need much power, have you looked into using ARM7 based u-controller? A lot of them have enought I/O to connect it to a ATA device easily and have internal flash memory as well, pricewise they are cheaper than u-controller+FPGA solution.

BR,
/Farhad

 

[rudenia]

how to choose fpga

hi
selection of fpga depends on some factor such as how big ur design is,what is maximum clock freuency,will u using pll or not,how much memory u want and more important the cost.

 

[Z80]

fpga best

Hi farhada

I guess you're right, FPGA alone is not too good an option. What I need is not speed but a lot of throughput. With this kind of stuff you need to take an error margin and I estimate that I'll need around 50 MIPS. What speed do ARM7 devices run at?
An earlier option was a MCU from Cygnal but they're too expensive. There are TI DSP's at 160 MIPS that cost around $10 / unit and that's a real bargain but they're way to complex for this king of app I think. A fast MCU would be perfect if it was cheap, maybe combined with a FPGA for the ATA interfacing part.

 

[bibo1978]

beste fpga

Hi,
If this is your last choice then I guess you can do what you want with a Spartan FPGA only "lowest price".

 

[farhada]

choose fpga

Hi Z80,
It will be really difficult to find a solution for less than $10.

I am using Analog Devices AD7026 which is an ARM7 based unit running at 40MHz (45 mips), but the price is pretty high ($26 in 100s). It has everything I need plust a small PLD that I use to controll the logic to connect a Compact Flash to it directly.
**broken link removed**

**broken link removed**

And to be honest with you, I don't think the learning curve for a FPGA based project is much less than a TI DSP, but the startup cost for your project will be much less since most of the FPGA companies are giving away their tools for free (limited edition).

One option is the use of DSPIC units, I am not sure how much they cost, but you will have enough horsepower as well as I/O to handle the ATA interface.

BR,
/Farhad

 

[Z80]

which is best fpga

As a matter of fact dsPIC was an early option but I was worried aboiut the speed (30 MIPS last time I checked). The good thing about those devices is that they're very well documented, nice SW tools (HI-TECH rules), but I wish they were faster.

 

[eltonjohn]

how to choose fpga board

Hey Farhada !
Are you using the analog devices already ? Are you running code on the chip ? .I talked to their support people and they told me that the chip has problems . What are your experience with it so far !

 

[farhada]

fpga chip

Hi Eltonjohn,
I got samples of their components, the 7020 and 7026. I am waiting for my board to arrive so I can start using the ICs.

The only thing I didn't like about this chip is that the PWM can not be used if you use an external memory. With only 8kWord of memory, I really needed to add extra SRAM to it, but then I was unable to use the PWM instead. It is kind of silly, and I have already told our AD reps about it.

I let you know when I got the board and start using it.

BR,
/Farhad

 

[eltonjohn]

best fpga boards

So you ordered the eval board for the microconverter?

I posted the support site a while back :
**broken link removed**

you can dowload here the PLA tool and other examples ..etc

 

[farhada]

best fpga board

Hi,
Actually no, I am working on a project to create a small modular design based on AD micro converter family. There are other quys working on the SW part, I am just writing some minor test code to make sure the HW works. and on the next design, to make sure the FPGA/7026 communication work well and the boot loader inside the 7026 can download the configuration of the FPGA from a Compact flash and start the application.

Z80
I am not sure if you can find anything "simple" for that kind of speed. 50 Mips is a lot of hourse power for a controller. Most of the devices in that category are very sofisticated and advanced units like Motorola digital DNA devices, they cost about $30 in 1000s, but the initial cost of working with them is pretty high. But on the other hand you get a 300mips floating point unit with almost everything you ever need inside the chip, the they are only available in BGA package and they cost 3-400 US$ in samples.

And when you talk about MIPS, what do you mean with it? Is it your datarate or is it the actual computing power you need? Because MIPS really doesn't mean anything other than a marketing BS from the companies (IMHO anyway).

Best regards,
/Farhad

 

[Z80]

choosing fpga

I guess you're right, MIPS is kinda bullshit, they never tell you that the advertized MIPS is best-case. If you are willing to bare with me some more I can give you more details about the project, maybe you can recommend a better solution that I was able to come up with.

 

[farhada]

how to choose the right fpga

No problem,
Send me a PM and we take it from there if you feel more comfortable. I have a lot of time on my hand right now, until next week then I will be busy and will not be so active on the board any more.

BR,
/Farhad