FreeBASIC provides the experimental nuttx-riscv32 compiler target, a NuttX runtime, low-memory gfxlib2 support, sfxlib integration, examples, compatibility patches, and host workflow tools. The compiler emits C that is compiled inside the matching Apache NuttX application or loadable-module build.

The source tree does not vendor NuttX. The helpers clone or reuse an external nuttx/ and apps/ workspace so the NuttX version, board, and configuration remain explicit.

The freebasic-nuttx Debian package installs the runtime source SDK and these commands:

Use each command's --help output and installed manual page for its complete option list.

The shortest end-to-end compiler and runtime check is:

It prepares the workspace, builds the default FreeBASIC example into a RISC-V NuttX image, runs qemu-system-riscv32, and checks the console result. Use --bas program.bas to select a program, --prepare-only to stop after workspace setup, and --with-gfxlib to link the NuttX graphics support.

Firmware preparation is separate from application deployment:

The firmware command builds the configured NuttX image. The application command builds a loadable module, transfers it to /data/fb or /mnt/sd0/fb, and can start it through a telnet or serial NSH console. --no-upload keeps the operation local.

The RP2350-PiZero helper builds an ELF intended for /mnt/sd0/bin. A separate PowerShell YMODEM helper can transfer it through an already configured NSH console. Rebuilding one program does not require reflashing the firmware.

Small boards impose real limits on framebuffer pages, heap, thread stacks, media decoders, and network buffers. DVI, USB host, SD, Ethernet, serial, GPIO, and audio paths need the matching physical board. QEMU can prove compiler, runtime, filesystem, and network paths but cannot replace those hardware checks.