Programming the Open-V Open Source CPU on the Web

openriscv_webYou can now program the Open-V on the web, and see the results in real time. The code is compiled in the web IDE and then flashed to a microcontroller which is connected to a live YouTube live stream. It’s pretty neat to flash firmware on a microcontroller thousands of miles away and see the development board blink in response.

We’ve covered the Open-V before, and the crowd funding campaign they have going. The Open-V is an open hardware implementation of the RISC-V standard. And is designed to offer Cortex M0-class capabilities.

This feels like a create way to play around with some real hardware and get a taste of what a future where we can expect Arduino-like boards, open source down to the transistor level.

For a closer look at why open silicon matters, check out [Brian Benchoff’s] hands-on review of the HiFive, an Arduino form-factor board built around an open hardware RISC-V microcontroller.

HiFive1: RISC-V In An Arduino Form Factor

The RISC-V ISA has seen an uptick in popularity as of late — almost as if there’s a conference going on right now — thanks to the fact that this instruction set is big-O Open. This openness allows anyone to build their own software and hardware. Of course, getting your hands on a RISC-V chip has until now, been a bit difficult. You could always go over to opencores, grab some VHDL, and run a RISC-V chip on an FPGA. Last week, OnChip released the RISC-V Open-V in real, tangible silicon.

Choice is always a good thing, and now SiFive, a fabless semiconductor company, has released the HiFive1 as a crowdfunding campaign on CrowdSupply. It’s a RISC-V microcontroller, completely open source, and packaged in the ever so convenient Arduino form factor.

The heart of the HiFive1 is SiFive’s FE310 SoC, a 32-bit RISC-V core running at 320+ MHz. As far as peripherals go, the HiFive1 features 19 digital IO pins, one SPI controller, 9 PWM pins, an external 128Megabit Flash, and five volt IO. Performance-wise, the HiFive1 is significantly faster than the Intel Curie-powered Arduino 101, or the ARM Cortex M0+ powered Arduino Zero. According to the crowdfunding campaign, support for the Arduino IDE is included. A single HiFive1 is available for $59 USD.

Since this is an Open Source chip, you would expect everything about it to be available. SiFive has everything from the SDK to the RTL available on GitHub. This is an impressive development in the ecosystem of Open Hardware, and something we’re going to take a look at when these chips make it out into the world.

Open-V, The First Open Source RISC-V Microcontroller

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.

A render of the Open-V dev board

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.