Internal Example, Device and Board Development

Example

Internal examples mean examples which are located in examples_int repository folder.

In this chapter, we only focus on repository example, not freestanding example.

The construction of internal examples is no different from the public examples in examples folder. Please refer Example Development chapter for more details.

Internal examples can support both public boards or internal boards. For public boards supported internal examples, they will only be developed in internal repository and won’t be public in any cases.

Device

Internal devices are located under devices_int repository folder. The construction of internal devices are no different from normal public devices. Please refer Device chapter for more details.

In the device variable.cmake located in the root of Internal devices, the device_root variable shall be set to devices_int to indicate that the device contents are located under devices_int folder:

mcux_set_variable(device_root devices_int)

For public device, the device_root value is devices.

The internal device can only be used by internal boards because either of them can or will be public.

Board

Internal boards are located under examples_int/_boards repository folder. The construction of internal boards are no different from normal public boards except the example.yml.

For public boards, the board example.yml is used to provide board level supported toolchains and build configuration targets. In each example, the example self example.yml will provide customized boards/toolchains/build configuration targets which work together with board example.yml to decide the final example boards/toolchains/build configuration targets enablement status. You can refer example.yml chapter for more details.

For internal boards, since it cannot be exposed in the public example example.yml boards data attribute to indicate they are supported by the public examples, so we introduce new rules for internal board example.yml: the supported examples will be directly listed in the internal board example.yml like

board.toolchains: 
- +armgcc@debug
- +armgcc@release
- +iar@debug
- +iar@release
- +mdk@debug
- +mdk@release

hello_world:   
  toolchains:        # optional
    - +iar@ddr_debug # add a new build configuration target
    - -mdk@debug     # reduce a build configuration target

In the above example, the hello_world example supports

• iar toolchain with debug, release and ddr_debug build configuration targets

• mdk toolchain with release build configuration target

• armgcc toolchain with debug and release build configuration targets

In this way, just with the single board example.yml, we can get all the supported examples with the toolchains and build configuration targets.

In the board variable.cmake located in the root of Internal boards, the board_root variable shall be set to examples_int/_boards to indicate that the board contents are located under examples_int/_boards folder:

mcux_set_variable(board_root examples_int/_boards)

For public board, the board_root value is examples/_boards.