Sipeed Teases a $40 Single-Board Computer with Fully-Ratified RISC-V Vector Extensions

Boasting a Kendryte coprocessor, two heterogeneous cores, and support for running User-mode 32-bit code, Sipeed's next SBC is unusual.

Sipeed has posted images teasing a new single-board computer based on a RISC-V processor boasting the ratified RISC-V Vector Extension 1.0 — something which should give a considerable boost to on-device machine learning and artificial intelligence workloads.

"What about [a] 1.6GHz RISC-V C908 chip with RVV1.0," Sipeed posted to its official Twitter account this week, referring to Alibaba's T-Head XuanTie C908 RISC-V core design. "Do you want a C908 SBC [Single-Board Computer] $30~$40?"

What makes the chip showcased by Sipeed interesting is that it's primary core, which runs at 1.6GHz, includes the RISC-V Vector Extension (RVV) 1.0 — the fully-ratified version, rather than the earlier pre-ratification 0.7.1 release which at the time of writing was the only version to have made its way into commercially available silicon. As a result, the chip should boast a big boost in performance for applications which can make use of vector acceleration — like on-device machine learning workloads.

Sipeed has been unusually silent on precise details surrounding the chip on which it plans to build a single-board computer, but a partially-redacted block diagram released by the company suggests it's an as-yet unannounced Canaan Kendryte chip — complete with Kendryte Processing Unit (KPU), a dedicated machine-learning accelerator with 2MB of static RAM (SRAM).

The block diagram also reveals a second processor core, running at 800MHz and without the RVV extensions, a security subsystem with true random number generator (TRNG), a power management system, a multimedia subsystem with 3D depth engine and 2.5D graphics processor, support for DDR3L,LPDDR3, and LPDDR4 memory, an image signal processor (ISP) block, and two USB 2.0 ports, two SD/eMMC peripherals, SPI, I2C, UART, and up to 64 general-purpose input/output (GPIO) pins including six pulse-width modulation (PWM) channels and a 12-bit analog to digital converter (ADC).

In a post to Reddit, former SiFive developer Bruce Hoult revealed another trick up the chip's sleeve: "[It] supports running RV32 [32-bit] code in User mode (only) on an RV64 [64-bit] core," he claims. "This is common on x86 and Arm but I don't know of any other RISC-V core that can do this. Arm, btw, has dropped this feature from their 2023 and on Armv9-A cores. No question, I'll be first in line to plonk down $30-$40 for such a machine!"

Sipeed has not yet offered a launch schedule for the new board, with interested parties advised to follow the company's Twitter account for more information when it's available.

Gareth Halfacree
Freelance journalist, technical author, hacker, tinkerer, erstwhile sysadmin. For hire:
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