Development tools for Zephyr on STM32Workbench for Zephyr: VS Code extension to set up, build, flash and debug Zephyr applications on STM32.Devicetree manager: browse, edit and visualize Zephyr devicetree, STM32CubeMX-like for Zephyr.
Hi, usually the __IO is defined in the core_cm0.h file located in the
...\STM32Cube_FW_L0_VX.X.X\Drivers\CMSIS\Include folder.
Are you using this file/path?