Hello mbed world,

I believe I need your help once again. I am continuing a project I conducted last year for my science fair (check out http://www.intel.com/education/isef/profiles.htm#Dylan for info.) and I need to decide on a better processor (I was using the Arduino before) to process a whole lot of data. Let's say 2 640x480 colour images along with intensive processing (hue colour space conversion + blob detection + binocular distance calculation) at hopefully around 15 fps (as long as it's higher that 5 fps, I'm good).

So far I have come down to two final products, the mbed (it's a bit slow for my project so I'll almost definitely have to go to a different MCU probably along the lines of a 266 Mhz LPC or a SAM7/9 of similar or greater quality) or a low-cost Spartan 3E dev board (I was thinking that Digilent's Nexys2 with its student discount has the best bang for its buck, but I'm up for directing my attention to a new board or a new FPGA entirely). Unfortunately, I know very little about FPGAs (0 experience) and how they compare to MCUs especially. I'm not too worried about learning a HDL (hopefully like C or even C#) though.

Therefore, any help into the right direction would be wonderful.

Hi Dylan,

Sounds like an excellent project!

Perhaps you could get the best of both worlds?:

• http://www.actel.com/products/SmartFusion/

This is an ARM Cortex-M3 and FPGA fabric in a single chip. Might be exactly what you are looking for?

Simon

Thanks for the reply Simon!

I checked out SmartFusion and it definitely seems like an awesome chip, but there's a catch to it.  After looking at the dev kit that Actel had, I was pretty impressed though it did not have a VGA port or PS/2 port which would be necessary for human interaction and output display.  Yet, once I looked at the price ($999, almost 3 times my entire budget!), it was obvious that it wasn't going to give the best bang for my buck.  Even the eval kit (priced at $99; big price jump) just didn't seem like what I needed for my project.  I love Actel's concept in making the SmartFusion (I don't think any other chip series has FPGA and Cortex-M3 integrated), but for my budget, it doesn't quite seem like the best choice.

So, I guess I'll just keep searching for the right choice, though Digilent's Spartan 3E board is looking pretty high and mighty right now, since I don't need to purchase right away.  By the way, is there anyway exactly to compare a FPGA and a MCU for speed and program size or does it all just depend on how well the program is in parallel on the FPGA?

Sincerely,
Dylan Dalrymple

Dylan,

I think you'll have trouble fitting your design in a Spartan 3E - maybe a Spartan 6. Best bet is to call the Xilinx rep (or Avnet) and give them a brief overview of your requirements. Deciding on a hardware platform is difficult for FPGAs if you're starting from 0. The size measurements given by the manufacturers are hard to compare across vendors. If this is for a class project you probably want to stick with a processor or a processor with FPGA fabric.  Good luck and keep us posted.

Pat

Actually, I did the math and figured out that a mini ITX motherboard with a 1.6 ghz dual core Intel Atom processor along with all of the necessary parts that I need for it costs about the same if not less than my other solutions (FPGA, Beagleboard, mbed-similar device, etc.) while being about 3 times more powerful (not to forget the dual core part which would be really nice for working with two images at once).  From this motherboard, I can just use 2 webcams (or the minoru) through usb along with other inputs and send serial messages to an mbed or arduino for it to control motors.  This way I would definitely have a little overkill (especially if I used a minimalistic OS) to make sure just how much power I need to make a finished product.

Thank you all for your help (and I'm definitely going to post my question to the Xilinix reps either way, Pat), and I will definitely post a link to my completed projects page whenever I finish for everyone to see.

Dylan Dalrymple