Open Source software has been around for decades. Over these decades, Open Source software has been the driving force behind most of the Internet, and all of the top-500 supercomputers. The product of the Open Source software movement is perhaps more important than Gutenberg’s press. But hardware has not yet fully embraced this super-charging effect of openness. Being able to simply buy an open source CPU, free of all proprietary bits and NDAs is impossible.
Now, this is finally changing. OnChip, a startup from a group of doctoral students at the Universidad Industrial de Santander in Colombia, have been working on mRISC-V, an open 32-bit microcontroller based on the RISC-V instruction set. It’s now a crowdfunding campaign, and yes, you can simply buy an open source chip.
We’ve taken a look at onchip’s Open microcontroller project before. The team has made significant progress of moving from something that can run on an FPGA to the tapeout of a real, physical chip. The onchip twitter timeline is a flurry of activity, with real silicon and a prediction that 50% of low-end microcontrollers will be running RISC-V in a decade.
If you want to get your hands on one of these open microcontrollers, the Crowd Supply campaign is actually fairly reasonable, considering this is custom silicon. $49 USD gets you a first-run mRISC-V in a QFN-32 package. $99 gets you the mRISC-V dev board with an SD card slot, USB, regulators, and of course the micro itself.
This chip’s capabilities are almost on par with a low-power ARM Cortex M0. The chip itself runs at 160MHz, has SPI, I2C, SDIO, and JTAG, as well as a 10-bit 10MS/s ADC and a 12-bit DAC. There are 16 GPIO pins on mRISC-V. You won’t be able to build a smartphone or laptop with this chip, but you will be able to build an Internet of Things gizmo.
While OnChip’s efforts won’t result in a completely open source smartphone, there are other projects in the works that will bring an Open Source core to more powerful devices. lowRISC is a project to bring a Linux-capable System on Chip to production, and various people smarter than us have brought GCC, LLVM, and QEMU to the architecture.
Most of the efforts to bring the RISC-V architecture, and indeed most Open Source processors, have focused on the big chips — full CPUs and SoCs. Onchip’s mRISC-V goes the other direction to create a small, open microcontroller. If you’re looking to create an ecosystem of Open processors, this makes a lot of sense; there are more Honda Civics on the road than Lamborghinis, and Microchip and TI ship far more microcontrollers every year than Intel ships CPUs.