freertos_blinky¶

Reference NSX application that runs the optional nsx-freertos module on the boards declared in nsx.yml, spanning Cortex-M4F and Cortex-M55 targets. It creates a single FreeRTOS task that prints a tick counter (and the vendored kernel version) once every 500 ms, then starts the scheduler.

This is the canonical integration example for the FreeRTOS enablement work: it demonstrates the nsx::freertos_config contract, application-owned hooks, and both FreeRTOS port paths exercised by NSX today: Cortex-M55 (ARM_CM55_NTZ) on Apollo510 and Cortex-M4F (ARM_CM4F) on Apollo4P.

The manifest is also a multi-target proving ground: a single lean nsx.yml declares a targets: block for the supported boards and layers the optional nsx-freertos module via the top-level modules: list on each board's derived <board>_minimal profile.

How FreeRTOS is wired in¶

The nsx-freertos module deliberately does not ship a FreeRTOSConfig.h. Kernel configuration is application policy, so the app publishes it through the nsx::freertos_config interface target. This example does that in examples/freertos_blinky/CMakeLists.txt before nsx_bootstrap_app() adds the module:

add_library(app_freertos_config INTERFACE)
target_include_directories(app_freertos_config INTERFACE
    ${CMAKE_CURRENT_LIST_DIR}/config)
add_library(nsx::freertos_config ALIAS app_freertos_config)

The kernel config lives in examples/freertos_blinky/config/FreeRTOSConfig.h (seeded from the module template). On ARMv8-M the kernel's strong SVC_Handler, PendSV_Handler, and SysTick_Handler override the startup's weak vectors automatically. On Cortex-M4F, nsx-freertos provides strong shim handlers that route those vectors to FreeRTOS' vPortSVCHandler, xPortPendSVHandler, and xPortSysTickHandler entry points. No application handler remapping is needed in either path.

The application also provides the hooks the config enables (vApplicationMallocFailedHook, vApplicationStackOverflowHook) in examples/freertos_blinky/src/main.c.

Build & Run¶

# Default board (apollo510_evb)
nsx configure --app-dir .
nsx build     --app-dir .
nsx flash     --app-dir .      # requires JLink + Apollo510 EVB
nsx view      --app-dir .      # opens SWO viewer

# Another supported board
nsx build     --app-dir . --board apollo4p_blue_kxr_evb

Expected Output¶

freertos_blinky: starting scheduler
freertos_blinky: tick 0 (kernel V11.1.0)
freertos_blinky: tick 1 (kernel V11.1.0)
freertos_blinky: tick 2 (kernel V11.1.0)
...

Messages repeat roughly twice per second. If you see only the starting scheduler line, the scheduler failed to start — check that the SoC's NSX_SOC_RTOS_PORT_GENERIC resolves to ARM_CM55_NTZ on Apollo510 or ARM_CM4F on Apollo4P, and that the shared application-owned FreeRTOSConfig.h stays aligned with the current SDK template.