Andrew "bunnie" Huang Prepares the "dabao," a Dev Board for Baochip's "Mostly-Open" X1 RISC-V MCU
Built atop Vexriscv and PicoRV32, this 22nm microcontroller is "mostly open" to the RTL level — and a low-cost dev board is on the way.
Noted maker Andrew "bunnie" Huang is preparing a crowdfunding campaign for the dabao, a compact development board designed as an evaluation board for the Baochip-1x — a microcontroller built around a core of "mostly-open" hardware design.
"The Baochip-1x is a mostly open RTL [Register Transistor Logic] RISC-V based MCU [Microcontroller Unit] fabricated in TSMC [Taiwan Semiconductor] 22nm," Huang explains of the chip which has caught his eye for the project. "Its Vexriscv CPU runs at 350MHz, and it integrates 2MB of RAM, 4MB of RRAM [resistive RAM] (similar to flash), USB 2.0 HS [High Speed], and a quad-core I/O [Input/Output] accelerator based on the PicoRV32 clocking at 700MHz. The 'dabao' is the first-generation development board for the Baochip-1x. It aims to be an affordable, easy way for developers to get familiar with the Baochip-1x."
The specifications of the Baochip-1x might not seem terribly stand-out, bar perhaps that quad-core accelerator that runs at twice the speed of the single-core CPU at the board's heart, but it's how the parts got there that is interesting: the chip is built atop the Vexriscv and PicoRV32 projects, both of which offer free and open source implementations of the open RISC-V instruction set architecture. While not all the underlying logic of the Boachip-1x is likewise open, it's considerably more accessible than proprietary alternatives from Arm, Espressif, and the like.
In addition to the main CPU running at 350MHz and the quad-core IO accelerator running at 700MHz, the chip includes a security subsystem running at 175MHz and including accelerators for common cryptographic and hashing operations plus a true random number generator (TRNG). Peripherals include the aforementioned USB High Speed controller and PHY plus two UART, three I2C, and two SPI buses, a camera input, SecureDigital Input/Output (SDIO), and general-purpose input/output (GPIO) connectivity including an analog to digital converter (ADC) and four-channel pulse-width modulation (PWM) support. The dabao brings these features out to breadboard-friendly castellated pin headers on a gumstick-format board with USB Type-C for power and data connectivity.
The source files for the open parts of the Baochip-1X are available on the Baochip GitHub repository under the weakly reciprocal version of the CERN Open Hardware License 2; those interested in picking up a dabao can sign up to Huang's Crowd Supply page to be notified when the campaign goes live.