# Minimalist Cortex-A9 design

Does anyone know of a good basic Cortex-A9 design? Something with just enough to run with power and ethernet? I'm looking for something as a starting point and maybe with eagle files.

edit: While this isn't my first time designing something. I do think I'm in way over my head still. I'm looking for something with a lot of horsepower, +1GHz. I really like the Panda board, and this would be my first choice. The only problem with it is the extras, the video, sound just use extra power and won't be used. The M3 is close in design, ie loadable via USB (SD card would be nice too). I really just looking for horsepower. I also didn't have a chip picked out, I wanted to leave that open, but was looking at the OMAP4430.

Thanks for all the input. I will likely just use a panda board unless some knows of a better design. I think the cost of eagle (full version) will put this project out of my range to prototype.

• you don't want to design for a BGA with that many balls with eagle, its really not designed to handling blind/buried vias very well. – Mark Oct 27 '10 at 0:32
• I don't have much trouble with blind or buried vias with Eagle; the interface works as well as any other system I've used, although I think you might have to have some German blood in you in order to really "grok" the way Eagle does some things. :-) I will admit that working with boards dense enough to require them makes me go cross-eyed. :-) – akohlsmith Feb 1 '11 at 2:24

Are you sure you need an A9? These are not "minimalist" or "basic" chips in any way.

The PandaBoard uses an OMAP4430 Cortex-A9 chip from TI, which has 547 balls and 216 pads on a 0.4mm pitch. Can you solder this chip, and/or create a layout for it? No, the 2-layer freeware version of Eagle won't cut it, no matter how hard you try.

I don't want to discourage you on your first question, but it looks like you've jumped in over your head. I'd suggest that you do one of the following:

• Look at using a simpler chip, like an M0 or M3. The ARM tag is a great place to start.
• Purchase a PandaBoard ($174 US) or similar dev board if you really want the A9. • Let us know that you're familiar with the challenges of using complex chips like this, and give us a part number you were considering. In this case, I'll shut up. Some additional information about your project would be helpful. If you think the Cortex M3 and A9 are "close in design" you may want to do some more research. Sure they share an ISA, but the types of products and complexity of boards that would be built with an M3 MCU vs. OMAP are worlds apart. We are talking, 50MHz vs. 1GHz+, < 1MB RAM vs. 128MB+, no GPU vs. PowerVR SGX, etc. I'm not a real EE, but I have done a PCB for an M3 part, and while that was relatively easy and doable with a few weeks of learning Eagle and going over M3 evaluation board schematics, I would not seriously consider doing an OMAP board for a startup/homebrew type project. If you think M3 is close but want more horsepower, maybe check out the newer Cortex M4 parts? They are buffed M3s, some have hardware FPU, VFPU and DSP features bolted on, they tend to run at higher clock rates, but again nowhere near the power of an OMAP. If you want OMAP horsepower but not all the peripherals, or want to do a custom board design for your own peripherals, there are a few companies that make OMAP system-on-modules that are packaged as a 200-pin SO-DIMM. You can make a custom daughterboard that has an SO-DIMM socket, power supply, and breaks out the IO lines you need at a much lower level of complexity than doing the whole system design. I don't think I've heard of any with Ethernet jacks but they are available with Wi-Fi and likely have Ethernet support that can be broken out on your daughterboard. Compared to Beagle or Panda they are more expensive, not sure about bare modules but kits with some accessories (a Panda-like daughterboard, touchscreen LCD, etc.) are in the$200-400 range.

Here is an example, there are several manufacturers that offer similar product lines: http://www.technexion.com/index.php/arm/ti-omap3530

If you just want an ARM with Ethernet, get an mbed.

• -1: The mbed has no Ethernet magnetics or jack onboard. There are dozens of other dev kits which include Ethernet functionality out-of-the box, but the mbed only has USB. – Kevin Vermeer Oct 26 '10 at 22:28
• +1 adding a magjack is not hard (there are also cheap breakout boards available) – Toby Jaffey Oct 26 '10 at 23:12
• Actually, you can just cut a cable and connect the bare wires. Magnetics are important if you plan to deploy on untested networks/use PoE, but it's not required for development. – Igor Skochinsky Nov 5 '10 at 16:01
• +1, the tour video shows the guys adding an rj45 right on the breadboard mbed.org/handbook/Tour – Matt Williamson Feb 1 '11 at 6:39

Is it the 1GHz you are looking for or the Cortex-A9 specifically (ethernet, etc.)? Have you looked at the open-rd.org boards or plug computers from Marvell? They are in the 1.2GHz range but are not Cortex-A9, I don't think. Hawkboard and Beagleboard have ethernet. All so far are similar price range of the Pandaboard. I like the open-rd because you can plug a laptop SATA hard drive right into it and not have to deal with flash based media (except for the initial boot).

• I really like the plug computers. – krapht Feb 1 '11 at 7:57

The Beagle Board is a pretty nice looking ARM setup too. It also has extras like A/V, but it's a little cheaper than the Panda at $149 vs.$174.

 it looks like you need to bring your own USB ethernet adapter though.