A bare metal system for the 32-bit RISC-V processor using the Longan Nano development board (GD32VF103).

riscv-collab/riscv-gnu-toolchain

According to the instructions, configure and compile the GCC toolchain and integrate it into the environment. Ensure that the toolchain supports rv32imac/ilp32 with the following specifications: @march=rv32imac and @mabi=ilp32.

$ riscv64-unknown-elf-gcc -print-multi-lib
.;
rv32i/ilp32;@march=rv32i@mabi=ilp32
rv32im/ilp32;@march=rv32im@mabi=ilp32
rv32iac/ilp32;@march=rv32iac@mabi=ilp32
rv32imac/ilp32;@march=rv32imac@mabi=ilp32
rv32imafc/ilp32f;@march=rv32imafc@mabi=ilp32f
rv64imac/lp64;@march=rv64imac@mabi=lp64
rv64imafdc/lp64d;@march=rv64imafdc@mabi=lp64d

1. Use GD32_MCU_Dfu_Tool. (only for Windows)
2. Use JTAG debugger with OpenOCD.
   • RV-Link / Jlink / FT2232H module / ...

• RISC-V spec.
  • Volume 1, Unprivileged Specification version 20191213
  • Volume 2, Privileged Specification version 20211203
• Core IP spec.
  • Nuclei Bumblebee Core - N200 (RISC-V ISA v2.2 RV32IMAC)
• Chip spec.
  • GigaDevice GD32VF103 RISC-V 32-bit MCU Datasheet
  • GigaDevice GD32VF103 RISC-V 32-bit MCU User Manual
    • RISC-V little-endian RV32IMAC (with 32GPRs).
    • 2-stage pipeline.
    • Support Machine (M) / User (U) privilege level.
• Development Board spec.
  • Longan Nano document
  • Longan Nano schematic