An Integration-Friendly Linux CPU: The PLUS1 SP7021
A brief look at the appealing features of the PLUS1 SP7021 Linux CPU.
For those of us that enjoy spinning our own development boards, an exciting and under-marketed little chip that was most recently showcased on the Banana Pi BPI-F2S single board computer gives reason for pause. The Banana Pi BPI-F2S SBC was featured as a project on Hackster back in early November of last year as an industrial-grade board.
The PLUS1 Application CPU from Tibbo Technology is an SoC with the horsepower to compete with other industrial Linux CPUs, while integrating with the same simplicity as a microcontroller chip.
At $20 per chip, the PLUS1 is not going to be the cheapest part on your BOM but it will save you some time and money in a few different areas such as power management and PCB layout which might make it worth the splurge.
For the exhaustive list of the specifications for the SP7021, check out the link to Tibbo Technology's website here. The features that caught my eye in particular start with the multitude of processor core options the chip has. Starting with a quad-core 1GHz ARM Cortex-A7 (CA7) processing unit, followed by a 202MHz A926 core for executing real-time code, and a low-power 202MHz/32KHz 8051 core for system management (including in low-power standby mode). Bonus: the GPIO lines are routed such that all cores of the chip can access them, which is huge.
As I'm dreading the layout of DDR memory on one of my other boards, the built-in DDR3 DRAM on the PLUS1 made me question my life choices. For those of you that know the struggle, I don't need to explain why this is appealing. There are currently two options for 512MB or 128MB. The 512MB option chip is the $20 chip, but I couldn't find where to buy the 128MB option. I can only assume the 128MB would be slightly cheaper.
Tibbo's feature list also claims that only a few passive need to be added externally for the chip's power other than the single 3.3V input due to built-in 1.5V, 1.2V, and 0.9V regulators. This makes PCB layout and power management drastically easier with this chip as well.
It's obvious that the PLUS1 is targeted toward the IoT applications market based these few features I've mentioned, and looking at the sample block diagram it really puts it in frame that you can layout any IoT or SBC board to your exact needs with it.
Tibbo's website mentions that there is a custom Yocto-based Linux image for the PLUS1 chip that is "modern" in the sense that it uses the latest kernels and C libraries available for the embedded Linux platform. I haven't been able to find any repositories for it yet however, so hopefully that will be made available at some point. This is also a huge bonus to get up and running quickly as creating an embedded Linux image from scratch is not a trivial task by any stretch of the imagination.