Sizing an FPGA

[Altera_Forum]

I'm looking at picking an FPGA for a design, but don't want to go too far in overkill on the size/complexity of the FPGA. The core functionality that I would like for it to have: 

• DRAM memory interface (16 bit data bus, no more than 64MB needed), SDRAM is preferred 
• 2 16-bit counters 
• Logic circuitry to gate certain events to occur at certain timer values. 

  I'm familiar with CPLD's, but have only used FPGA's for a limited number of projects.

[Altera_Forum]

It sounds like a simple design. Basically I suggest putting the logic together and building it.. 

 Your DRAM controller will be the most complex piece of logic and what ever state-machine you have controlling it.  The MAX10 family is definitely capable of handling this requirement, but it's brand new so only the 8K LE and 50K LE devices are really available at this time. (The rest of the family will come out over the next year)  I guess the real question is what are you doing with the SDRAM. Are you planning on putting a small CPU in the FPGA? or are you gathering data from some other source? If so, how are you getting the data out?  If you can get the design to build, you can then target the various FPGA's and see how much space it really takes.  Then pick a family and device accordingly. Otherwise, pick the device you think it will fit it, go one size up for feature creep, and make sure you have one more size up available in the same package just in case.  Putting different sized devices in the same package is not always one-to-one. So before you layout the board, Double check all the pinouts to make sure device migration doesn't have any issues with the layout.  Pete

[Altera_Forum]

Does cost come into your equation here for device selection? For your requirements I'd recommend you consider Cyclone IV E (over Cyclone V). Cyclone IV is a very widely available family with many device size and package options. 

 As Pete suggested MAX10 has limited availability and, because it's relatively new, you're still paying a premium. Low end Cyclone IV parts, which will do everything you want, are cheaper than MAX10 at present. Cyclone IV proved to be one of Altera's more popular families too. So, it's not going to go away any time soon (if you're concerned about longevity). I'd be tempted to suggest MAX10 has greater 'complexity' than Cyclone IV E anyway...  Quartus is free for these families. So, you have all the tools you need at your disposal. Put a design together and let Quartus choose the part for you. Then play around with the device settings - changing families and packages - until you find a balance of device size/complexity/price that suits you.  Cheers, Alex

[Altera_Forum]

Hi, perhaps you can refer to Altera Product Catalogue for the requirement that you are looking for 

https://www.altera.com/content/dam/altera-www/global/en_us/pdfs/literature/sg/product-catalog.pdf

[Altera_Forum]

--- Quote Start ---  I'm looking at picking an FPGA for a design, but don't want to go too far in overkill on the size/complexity of the FPGA. The core functionality that I would like for it to have: 

• DRAM memory interface (16 bit data bus, no more than 64MB needed), SDRAM is preferred 
• 2 16-bit counters 
• Logic circuitry to gate certain events to occur at certain timer values. 

  I'm familiar with CPLD's, but have only used FPGA's for a limited number of projects.  --- Quote End ---    You can also refer to the product selector tool (https://www.altera.com/products/product-selector-guide.html) to assist in part selection.

[Altera_Forum]

I appreciate all of the responses so far. I am intrigued by the possiblity of implementing the whole design in an FPGA. Cost is certainly an issue, but it is one thing that isn't set in concrete. A flexible design would allow programmability and upgrades a lot easier, which would reduce future costs. I'm just not as familiar with what can be done in a modern FPGA versus the decade or so old ones.

[Altera_Forum]

Hi mdavister, 

 Just wonder if you know your local FAE contact. Generally I would get their help in selecting the part that suit my application.