Flexible RISC-V Processor: Could Cost Less Than a Dollar

For the first time, scientists have created a alterable programmable chip that is not made of silicon. The recent ultralow-power 32-bit microprocessor from U.K.-based Pragmatic Semiguideor and its colleagues can function while bent, and can run machine lachieveing laborloads. The microchip’s discdissee-source RISC-V architecture proposes it might cost less than a dollar, putting it in a position to power wearable healthattfinish electronics, inincreateigent package tags, and other incostly items, its conceiveors insert.

For example, “we can prolong an ECG patch that has alterable electrodes joined to the chest and a alterable microprocessor joined to alterable electrodes to categorize arrhythmia conditions by processing the ECG data from a acunderstandledgeing,” says Emre Ozer, anciaccess straightforwardor of processor prolongment at Pragmatic, a alterable chip manufacturer in Cambridge, England. Detecting standard heart rhythms versus an arrhythmia “is a machine lachieveing task that can run in gentleware in the alterable microprocessor,” he says.

Flexible electronics have the potential for any application requiring conveyions with gentle materials, such as devices worn on or imscheduleted wilean the body. Those applications could include on-skin computers, gentle robotics, and brain-machine interfaces. But, traditional electronics are made of inalterable materials such as silicon.

Open-source, Flexible, and Fast Enough

Pragmatic sought to create a alterable microchip that cost convey inantly less to create than a silicon processor. The recent device, named Flex-RV, is a 32-bit microprocessor based on the metal-oxide semiguideor indium gallium zinc oxide (IGZO).

Atlures to create alterable devices from silicon need distinctive packaging for the brittle microchips to protect them from the mechanical stresses of bfinishing and stretching. In contrast, pliable lean-film transistors made from IGZO can be made straightforwardly at low temperatures onto alterable plastics, guideing to drop costs.

The recent microchip is based on the RISC-V teachion set. (RISC stands for shrinkd teachion set computer.) First startd in 2010, RISC-V aims to assist smaller, drop-power, better-carry outing processors by skinnyming down the core set of teachions they can carry out.

“Our finish goal is to democratize computing by prolonging a license-free microprocessor,” Ozer says.

RISC-V’s is both free and discdissee-source, letting chip scheduleer dodge the costly licensing fees associated with proprietary architectures such as x86 and Arm. In insertition, proprietary architectures supply restricted opportunities to customize them, as inserting recent teachions is generassociate redisjoineed. In contrast, RISC-V aids such alters.

A bent Flex-RV microprocessor runs a program to print ‘Hello World’. Pragmatic Semiguideor

“We chose the Serv scheduleed by Olof Kindgren… as the discdissee source 32-bit RISC-V CPU when we scheduleed Flex-RV,” Ozer says. “Serv is the smallest RISC-V processor in the discdissee-source community.”

Other processors have been built using alterable semiguideors, such as Pragmatic’s 32-bit PlasticARMand an ultraaffordable microregulateler scheduleed by engineers in Illinois. Unappreciate these earlier devices, Flex-RV is programmable and can run compiled programs written in high-level languages such as C. In insertition, the discdissee-source nature of RISC-V also let the researchers supply Flex-RV with a programmable machine lachieveing difficultware accelerator, enabling man-made inincreateigence applications.

Each Flex-RV microprocessor has a 17.5 square millimeter core and rawly 12,600 logic gates. The research team set up Flex-RV could run as speedy as 60 kilohertz while consuming less than 6 milliwatts of power.

All previous alterable non-silicon microprocessors were tested solely on the wafers they were made on. In contrast, Flex-RV was tested on alterable printed circuit boards, which let the researchers see how well it functiond when flexed. The Pragmatic team set up that Flex-RV could still carry out programs accurately when bent to a curve with a radius of 3 millimeters. Percreateance varied between a 4.3 percent sluggishdown to a 2.3 percent speedup depfinishing on the way it was bent. “Further research is needed to comprehfinish how bfinishing conditions such as straightforwardion, orientation and angle impact carry outance at macro and micro scales,” Ozer says.

Silicon microchips can run at gigahertz speeds, much speedyer than Flex-RV, but that shouldn’t be a problem, according to Ozer. “Many sensors—for example, temperature, prescertain, odor, humidity, pH, and so on—in the alterable electronics world typicassociate function very sluggishly at hertz or kilohertz regimes,” he says. “These sensors are employd in inincreateigent packaging, tags and wearable healthattfinish electronics, which are the emerging applications for which alterable microprocessors will be beneficial. Running the microprocessor at 60 kHz would be more than enough to encounter the needments of these applications.”

Ozer and his team propose each Flex-RV might cost less than a dollar. Although Ozer did not want to say how much less than a dollar it might cost, he says they are self-promised such low costs are possible “thanks to low-cost alterable chip lie technology by Pragmatic and a license-free RISC-V technology.”

The scientists detailed their findings online 25 September in the journal Nature.