Link errors - implementing TouchGFX with MbedOS

[George Journeaux]

I've been attempting to get TouchGFX running with MbedOS. I've got the program compiling but I'm getting some consistent link errors. Any suggestions on this?

Using ARMC6 (6.13) I get the following:

```

[Warning] @0,0: L3912W: Option 'legacyalign' is deprecated.

[Error] @0,0: L6218E: Undefined symbol touchgfx::HAL::instance (referred from BUILD/DISCO_F746NG/ARMC6/Middlewares/ST/touchgfx/framework/source/touchgfx/containers/CacheableContainer.o).

[Error] @0,0: L6218E: Undefined symbol touchgfx::Bitmap::dynamicBitmapGetAddress(unsigned short) (referred from BUILD/DISCO_F746NG/ARMC6/Middlewares/ST/touchgfx/framework/source/touchgfx/containers/CacheableContainer.o).

...

...

Finished: 0 information, 1 warning and 164 error messages.

```

All 164 errors are consistent undefined symbols coming from touchgfx files.

Correct me if I'm wrong, but this seems to be down to static members of a class not being defined in a .cpp that they are used in (Defining these members seems to fix the error)

(Like this: https://stackoverflow.com/questions/185844/how-to-initialize-private-static-members-in-c)

Is there any way other than correcting this in the 164 occurrences? (I'd rather not do this every time the touchgfx libraries are updated)

I've also tried using GCC ARM (9-2019-q4-major) as I thought it may be more compatible and I get the following:

```

[ERROR] c:/program files (x86)/gnu tools arm embedded/9 2019-q4-major/bin/../lib/gcc/arm-none-eabi/9.2.1/../../../../arm-none-eabi/bin/ld.exe: cannot find -lchgfx_core

c:/program files (x86)/gnu tools arm embedded/9 2019-q4-major/bin/../lib/gcc/arm-none-eabi/9.2.1/../../../../arm-none-eabi/bin/ld.exe: cannot find -lchgfx_core_release

c:/program files (x86)/gnu tools arm embedded/9 2019-q4-major/bin/../lib/gcc/arm-none-eabi/9.2.1/../../../../arm-none-eabi/bin/ld.exe: cannot find -lchgfx_core

c:/program files (x86)/gnu tools arm embedded/9 2019-q4-major/bin/../lib/gcc/arm-none-eabi/9.2.1/../../../../arm-none-eabi/bin/ld.exe: cannot find -lchgfx_core_release

c:/program files (x86)/gnu tools arm embedded/9 2019-q4-major/bin/../lib/gcc/arm-none-eabi/9.2.1/../../../../arm-none-eabi/bin/ld.exe: cannot find -lchgfx_core

c:/program files (x86)/gnu tools arm embedded/9 2019-q4-major/bin/../lib/gcc/arm-none-eabi/9.2.1/../../../../arm-none-eabi/bin/ld.exe: cannot find -lchgfx_core_release

collect2.exe: error: ld returned 1 exit status

```

Any ideas?

Thanks!

[Martin KJELDSEN]

In the last case, for arm-gcc, the linker path has to be wrong in your makefile. How did you create this project?

/Martin

[George Journeaux]

@Martin KJELDSEN​ , thanks for the quick response!

I started from a demo project from the TouchGFX designer and took the files I needed. From reading through the touchGFX support documentation I suspected that it was something to do with the linker path, but I have no experience in linkers - probably something worth me reading up on if anyone can recommend anything? - I'll give this a go and let you know!

@LTimm.1​, sounds like you've done this in a similar way.

If you don't use CubeMX, are you setting up the peripherals using the Mbed library functions? - I'd be interested in doing this to have a MbedOSxTouchGFX template that is somewhat compatible with any MbedOS compatible boards.

If you could share a bit more detail on how you set up your project that'd be super helpful!

[Martin KJELDSEN]

Okay, let me know! :) It should be pretty apparent from the Makefile. You just have to locate the library in your project folder

/Martin

[LTimm.1]

Martin beat me to it. :)

We are also using TouchGFX together with Mbed-OS, so can confirm that it's doable and working :)

I haven't tried the ARMC6 compiler though, we are using GCC....

[Martin KJELDSEN]

Great to hear, @LTimm.1​ ! :) Just out of curiosity, any interesting issues getting this to work? Seeing that CubeMX only supports FreeRTOS /CMSIS OS and the TouchGFX Generator therefor is only able to provide OS Wrapper/Driver for that.

/Martin

[LTimm.1]

Mbed-os is cmsis compatible, so we just used the provided OSWrapper_cmsis.cpp. Can't remember if we needed to do any tweaks. It was minimal if any.

We don't use CubeMX or TouchGFX generator. We started our project before those came along. I started with the STM32L4 demo project that the Designer can generate, and then took the elements I needed from that.

We still use the Designer for all UI updates though.

[Martin KJELDSEN]

E.g. here's the linker path in our arm-gcc Makefiles (/gcc/Makefile - in the root of an appliation created from an Application Template with the designer)

library_include_paths := $(touchgfx_path)/lib/core/$(platform)/gcc

Where touchgfx_path points to the touchgfx folder, most often in Middleware/ST.

/Martin