1. Download and install toolchain

$ curl https://github.com/hpmicro/riscv-gnu-toolchain/releases/tag/2022.05.15

2. Download and install openocd

Download hpmicro sdk_env, openocd in the path: sdk_env/tools/openocd

3. Configure and build NuttX

$ mkdir ./nuttxspace $ cd ./nuttxspace $ git clone https://github.com/apache/nuttx.git nuttx $ git clone https://github.com/apache/nuttx-apps.git apps $ cd nuttx $ make distclean $ ./tools/configure.sh hpm6750evk2:nsh $ make menuconfig $ make V=1

Note: make menuconfig to config toolchain ================== To switch GNU riscv64 toolchain to GNU riscv32 toolchain, the following option must be selected:

System Type  --->
    Toolchain Selection   --->
        [ ] Generic GNU RV64 toolchain
        [x] Generic GNU RV32 toolchain

Make sure HPMicro GNU riscv32 toolchain have been installed and be found in PATH.

4. Debug the nuttx with openocd and run

$ picocom -b 115200 /dev/ttyACM0

When using fireDAP, command as follows. Those cfg files in the path: sdk_env/hpm_sdk/boards/openocd. $ openocd -f probes/cmsis_dap.cfg -f soc/hpm6750-single-core.cfg -f boards/hpm6750evk2.cfg

$ riscv32-unknown-elf-gdb ./nuttx (gdb) target extended-remote [ip_addr]:3333 (gdb) load (gdb) c