Looking for a suitable SbC candidate, my search turned up a few options, each with their own caveats. For example the OSD335x from Octavo Systems, which is quite costly at £40, and while the ball pitch is very forgiving (1.27mm) it is still nonetheless a BGA, which was a higher assembly difficulty compared to, for example, the iMX233.

Another option would be something like the iMX6 PoP (Package-on-Package), which is essentially two BGAs sandwiched together, one being the processor and the other being the SDRAM. This option is also cost prohibitive and is significantly more complex in assembly terms than either of the previous choices.

I also found an interesting little module from Allwinner, the R8M. This is the module found on the original “$9 computer” C.H.I.P SBC, which gained a lot of media attention during its kickstarter campaign in 2015. Really though, I felt like I was “cheating” already by looking for integrated SDRAM, and the R8M felt even more like cheating due to it being a complete module. It is also unfortunately about as available as unicorn poo (at least outside of China).

I had put the project on hold at this point, until about a month ago when I discovered the Allwinner V3s, a 1.2GHz ARM Cortex-A7 with integrated 512Mbit (64M) DDR2 and various peripherals such as ethernet PHY, USB OTG, LCD output, MIPI interface, etc. This SoC is primarily aimed at the dashcam market but it works just as well as a generic Linux system, which can be integrated pretty easily into any project. Plus, it costs just $5 and it’s in a 0.4mm pitch QFP package! Easy!

I purchased by V3s from eBay UK, but it is also available on Aliexpress.