There’s been some exciting news about RISC-V microcontrollers recently with Gigadevice announcing GD32V, one of the first RISC-V general-purpose microcontrollers, which outperforms its Arm Cortex-M3 equivalent in terms of performance and power consumption.
The company also announced some development boards, but they are not quite that easy to purchase being listed on Tmall website in China. The good news is that Sipeed has introduced Longan Nano development board powered by GD32VF103CBT6 microcontroller, and it’s up for sale on Seeed Studio for $4.9.
- MCU – Gigadevice GD32VF103CBT6 32-bit RISC-V (rv32imac) microcontroller @ 108 MHz with 128KB Flash, 32KB SRAM
- Storage – MicroSD card slot
- Display – 0.96″ 160×80 IPS RGB LCD connected via SPI
- USB – 1x USB Type-C port for power and programming
- Expansion – 2x 16 through holes (2.54mm pitch) exposing 3x USART, 2x I2C, 3x SPI, 2x I2S, 2x CAN, 1x USBFS (OTG), 2x ADC (10 channel), 2x DAC
- Timers – 4x general-purpose 16-bit timer, 2x basic 16-bit timer, 1 x advanced 16-bit timer
- Crystals – 8MHz Passive High-Speed Crystal +32.768KHz Low-Speed RTC Crystal
- Debugging – 2x 4-pin JTAG debug interface
- Misc – Watchdog; RTC; Systick; Boot and Reset buttons
- Power Supply – 5V via USB-C port. Specs don’t mention it, but LiPo battery may be supported via VB/GND pins. It would be good, as GD32V only consumes 1/3 of Arm Cortex-M3.
- Dimensions – 46.1 x 20 mm
Longan Nano, which Sipeed also calls “Red Bill” in reference to STM32 Bluepill board, can run RT-Thread & LiteOS operating systems, and software development can be performed with tools such as the PlatformIO IDE, the Arduino IDE (soon), GCC and OpenOCD.
There are three ways to load firmware to the board: USB DFU download, UART ISP download, JTAG download. The first method just requires a USB-C cable, and the others a USB-UART debug board and a JTAG-enabled debugger (e.g. J-Link) respectively.You can find GD32V development platform for PlatformIO on Github, download software & hardware documentation and tools from an HTTP folder, and get support via Telegram. There’s also a documentation website, but at the time of writing, it’s pretty much empty.
Beside the LCD display, Longan Nano also ships with an acrylic case.
RV32 board Longan Nano Play BadApple~ pic.twitter.com/Xm9JMWbjud
— Sipeed (@SipeedIO) August 23, 2019