[docs] clarify "customization" section of BSP page

[WasabiFan]

Minor updates. I did make a change to the actual meaning of the instructions by changing a path, so please make sure I didn't make a mistake. I see:

• Break one step into two, and clarify the wording of the first half
• Correct path to copy files from: there isn't an extra path segment after the "board" directory

[salkinium]

Thanks, this is clearer!

[WasabiFan]

Ya know... I think this needs more steps. Because if you follow it as stated, due to #285, you get this:

(modm) D:\kaeli_000\Source\Repos\modm-test-project\modm-test-project>scons build
scons: Reading SConscript files ...
scons: done reading SConscript files.
scons: Building targets ...
�[;0;32mCompiling C++·· �[;0;33mbuild\modm-test-project\release\main.o�[;0;0m
Compiling C++·· build\modm-test-project\release\modm\src\modm\architecture\driver\atomic\flag.o
Compiling C++·· build\modm-test-project\release\modm\src\modm\board\board.o
Compiling C++·· build\modm-test-project\release\modm\src\modm\platform\clock\rcc.o
Compiling C++·· build\modm-test-project\release\modm\src\modm\platform\clock\systick_timer.o
Compiling C++·· build\modm-test-project\release\modm\src\modm\platform\core\assert.o
Compiling C++·· build\modm-test-project\release\modm\src\modm\platform\core\delay.o
Compiling C++·· build\modm-test-project\release\modm\src\modm\platform\core\heap_newlib.o
Compiling C···· build\modm-test-project\release\modm\src\modm\platform\core\startup.o
Compiling C···· build\modm-test-project\release\modm\src\modm\platform\core\startup_platform.o
Compiling C···· build\modm-test-project\release\modm\src\modm\platform\core\vectors.o
Compiling C++·· build\modm-test-project\release\modm\src\modm\platform\gpio\enable.o
Compiling C++·· build\modm-test-project\release\modm\src\modm\platform\spi\spi_master_5.o
Create Library· build\modm-test-project\release\modm\libmodm.a
Linking········ build\modm-test-project\release\test.elf
d:/tools/gnu tools arm embedded/8 2019-q3-update/bin/../lib/gcc/arm-none-eabi/8.3.1/../../../../arm-none-eabi/bin/ld.exe: build\modm-test-project\release\modm\libmodm.a(board.o): in function `modm_abandon':
D:\kaeli_000\Source\Repos\modm-test-project\modm-test-project/modm\src\modm\board/board.cpp:19: multiple definition of `modm_abandon'; build\modm-test-project\release\custom-boards\stm32f411e-disco\board.o:D:\kaeli_000\Source\Repos\modm-test-project\modm-test-project/custom-boards\stm32f411e-disco/board.cpp:19: first defined here
collect2.exe: error: ld returned 1 exit status
scons: *** [build\modm-test-project\release\test.elf] Error 1
scons: building terminated because of errors.

[salkinium]

Thanks, this is clearer!

I need to go get some sleep.

[WasabiFan]

we should also clarify this while we're at it... if I figure out what it means I'll update the PR

[salkinium]

Since you're using a custom board config, you cannot extend the modm config anymore, or there would be conflicts. Technically you now need to manually merge the board.xml into your project.xml.

[salkinium]

And then obviously modify the config to your needs.

[WasabiFan]

The part I'm unsure about is "copy the pre-defined options into your own config". I clearly need to copy in the module dependencies, but then now I presumably need to do something to replace:

modm/src/modm/board/disco_f429zi/module.lb

Line 40 in 22e9b60

env.collect(":build:openocd.source", "board/stm32f429discovery.cfg");

And I am not sure what that is yet.

And then I need a target option set, which is listed in another repo (e.g. here).

[salkinium]

Yes, that depends on your board. There's probably no predefined openoce config, you'll need to provide your own (see https://modm.io/reference/module/modm-build/#openocdsource).
You can also lbuild discover -n :target for the target, but you should already know the identifier.

[asmfreak]

I'm using my own custom BSP copied over from modm with some added quality-of-life stuff like logging and fault handler included in BSP and several assumptions on board usage.

[salkinium]

This has been clarified in the new guide: https://modm.io/guide/custom-project/#using-a-board-support-package