Arduino on $4.9 RISC-V Board

PlatformIO IDE

Sipeed Longan Nano - RISC-V GD32VF103CBT6 Development Board

RT-Thread IoT OS

Arduino IDE

<h3 >Longan Nano</h3>Sipeed Longan Nano could be the most inexpensive RISC-V development board currently available. With only <a href="https://www.seeedstudio.com/Sipeed-Longan-Nano-RISC-V-GD32VF103CBT6-Development-Board-p-4205.html">$4.9</a>, you will get 128KB Flash, 32KB RAM, 160x80 LCD, TF card slot and even an acrylic transparent case.<h3 >GD32V Series Microcontroller</h3>The main chip on the board is a GigaDevice GD32V Series microcontroller, GD32VF103CBT6. From the information provided by <a href="https://riscv.org/risc-v-cores/">RISC-V website</a>, it is a 32-bit SOC with RV32IMAC instruction set and its core named "Bumblebee".<h3 >Arduino Support</h3>Sipeed provides the basic <a href="https://github.com/sipeed/Longduino">board support for Longan Nano</a> and the board manager URL for Arduino IDE is: <code ><a href="http://bigbits.oss-cn-qingdao.aliyuncs.com/Arduino_for_GD32V/package_longduino_index.json">http://bigbits.oss-cn-qingdao.aliyuncs.com/Arduino_for_GD32V/package_longduino_index.json</a></code>Currently, the URL supports only Windows platform. For macOS or Linux, the alternative IDE is <a href="https://docs.platformio.org/en/latest/platforms/gd32v.html">PlatformIO</a>.<h3 >The Problem</h3>As I mentioned above, the board support package provides only the basic functions. There is no Serial library, no SPI library,...<h3 >The Solution</h3><a href="https://github.com/onelife/Arduino_RT-Thread">Arduino RT-Thread library</a> comes to the rescue, which supports Longan Nano board from v0.8.1.RT-Thread is an open source RTOS, however also provides various drivers and utilities.For Longan Nano, the library currently provides UART, SPI, TF card and LCD drivers. Its utilities are mostly hardware independent, e.g. FatFS, tiny shell and etc. So with the single library, you may have a lot of fun.But there is one more thing (library), <a href="https://github.com/onelife/RTT-GUI/">RTT-GUI</a>. It is a GUI library based on RT-Thread, which provides some UI widgets, BMP / JPEG decoder, fonts and more. (The new problem now will be lack of memory space.)Enable RT-ThreadFor Arduino IDE, RT-Thread library supports Longan Nano board without any configuration, as the macro, <code >BOARD_SIPEED_LONGAN_NANO</code>, is defined in the board support package.For PlatformIO, following is an example of the configuration file, "<code >platformio.ini</code>".<pre ><code >[env:sipeed-longan-nano] platform = gd32v framework = arduino board = sipeed-longan-nano debug_tool = sipeed-rv-debugger lib_deps = RT-Thread, RTT-GUI build_flags = -D BOARD_SIPEED_LONGAN_NANO monitor_port = /dev/ttyUSB1 monitor_speed = 115200 </code></pre>Enable RTT-GUIEnablethefollowinglinesin "<code >guiconfig.h</code>". (Some features may be disabled in this file to save memory.)<pre ><code >#define CONFIG_GUI_DEVICE_NAME "ST7735" // RGB565 #define CONFIG_USING_RGB565 (1) </code></pre><h3 >Next Steps</h3><ul ><li ><a href="https://create.arduino.cc/projecthub/onelife/multitasking-on-arduino-b5f216">Multitasking on Arduino</a></li></ul><ul ><li ><a href="https://create.arduino.cc/projecthub/onelife/a-better-sd-library-with-rt-thread-242130">A better SD library with RT-Thread</a></li></ul><ul ><li ><a href="https://create.arduino.cc/projecthub/onelife/arduino-app-with-rt-thread-96438f">Arduino App with RT-Thread</a></li></ul><ul ><li ><a href="https://create.arduino.cc/projecthub/onelife/arduino-gui-library-865665">Arduino GUI Library</a></li></ul>

Arduino on $4.9 RISC-V Board

Longan Nano with GD32V series MCU costs only $4.9. You then got a Arduino board with 128KB Flash, 32KB RAM, LCD and even an acrylic case.