I don't yet know which ARM SoC (system on a chip) I'm going to use for the TuxedoBoard. Cost and features both weigh heavily on my mind when looking at what different vendors have to offer. I wrote an email spewing some of my thoughts on this topic yesterday and I'd like to share an edited version:
Due to my desired price point of about $100 for assembled and tested TuxedoBoards and because I expect the first build's volume to be about 100 boards, I'm looking to keep the SoC cost to under $8 each.
So far, I've not had success finding Cortex-A8 devices in the $8 range when purchased in quantities of about 100 units, regardless of vendor or features. There's quite a good variety of ARM9 parts in the $6 range that include all the features I think I'm interested in. I would prefer to use a Cortex-A8 part but if the cost is too high, ARM9 will get the job done and allow my price point.
BGA packages seem to be the only package offered for all Cortex-A8 and many ARM9 parts. That's OK with me as I've realized that selling an assemble-it-yourself kit isn't as important as making everything open so others can utilize the design. I'd prefer 1mm BGA ball pitch to allow for easy and cheap assembly but 0.8mm is second choice and would work fine. Pitch smaller than 0.8mm is a real turnoff to me because assembly tolerances get very tight and some assembly houses can't promise good yields. As I'm not looking to make the board into a mobile phone, or other space constrained device, physical size of the package isn't as important as ease and cost of assembly.
I'm not that excited about package-on-package (POP) memory, like used on the BeagleBoards. I get the impression that a good number of assembly houses aren't yet comfortable with POP and that the BeagleBoard team went through some issues with manufacturing yield at first. My first manufacturing run will only be around 100 boards, having yield issues would be very bad and ruin the finance side of things.
Freescale makes a very nice looking ARM9 core in the i.MX253. The i.MX253 prices out in the $6 range at Digi-Key. TI makes a competing ARM9 part in the AM1802 but I'm not clear on the pricing or features yet, still have to look into that.