Best Practices for Assembling Suitable sdk_config.h for a Project?

[chrisgr99]

I've read everything I can find in the documentation and on the forum about sdk_config.h.  I also installed the CMSIS configuration wizard.  However I'm still not clear what is the recommended way to assemble an sdk_config.h for for a project that needs a given set of peripherals and libraries.

Every example project has a custom version of sdk_config.h and then the master project has an sdk_config.h with everything defined.

I'm trying to merge the timer_pca1056 (timer blinking LEDs) project and the usbd_cdc_asm_pca10056 (USB UART) projects to use a timer to periorically send messages to the host.  I'm adding the timer code to the usbd_cdc_asm_pca10056 project.  However it did not build because timer symbols are not defined in sdk_config.h.

I carefully found the section in sdk_config.h of timer_pca1056 that defined the timer and pasted it into sdk_config.h of my new project, and now it builds correcty.

However this is tedious and very prone to error.

My question is, when one is defining a new project that uses specific peripherals and libraries, is the recommeneded practise to find the relevant sections of the master project sdk_config.h and assemble a custom sdk_config.h for the new project?  That would be a LOT of work.  How does one know what the relevant sections from the main project sdk_config.h are?  Is there any better way?

I saw a recommendation to include the entire master project sdk_config.h and then use app_config.h for all non-default settings.  Where is app_config.h and how does one add non-default settings to it?  Can anyone refer me to an example project that does it this way?

Also, I see that from looking at master project sdk_config.h with CMSIS that all the peripherals are marked as enabled.  Does this mean that they would be included in a build even if they are not needed?  If not, then what determines if a peripheral's code is included in the build?

What seems to be lacking is an overview of how to use the available tools to create a new project.  How do you experienced users of the SDK do it?

[tesc]

Hi,

Unfortunately the sdk_config.h files are not complete, and so you do need to copy sections manually when merging functionality from different examples. This is a known SDK bug. Yes, this is tedious and error prone, although the resulting configuration errors typically are easily discovered and easily fixed.

I saw a recommendation to include the entire master project sdk_config.h and then use app_config.h for all non-default settings.  Where is app_config.h and how does one add non-default settings to it?  Can anyone refer me to an example project that does it this way?

You just need to create a file named app_config.h and include it at the beginning of sdk_config.h. All defines in sdk_config.h are guarded by ifndefs so that a define is only set if it has not been set previously. That means, you can override anything in sdk_config.h by defining it before sdk_config.h is included. (Or, by defining it in app_config.h and include app_config.h at the very beginning of sdk_config.h.)

Also, I see that from looking at master project sdk_config.h with CMSIS that all the peripherals are marked as enabled.  Does this mean that they would be included in a build even if they are not needed?  If not, then what determines if a peripheral's code is included in the build?

What code is included or not is determined by what c files are part of the project. That means you must both add configuration and add the c files for the functionality that you need.

Regards,
Terje

[chrisgr99]

Thanks, that's very helpful.  One other question:

What is the best way to know the dependencies of a given feature?  i.e. If I include some library or peripheral how can I know what other libraries or peripherals need to be included?   I suppose one option would be to include everything in the example project for a given feature.  Are feature dependencies documented anywhere else?

[tesc]

Hi,

I am afraid those dependencies are not explicitly documented. Usually they are easily discovered, though, as you get compile time error messages for not finding include files and for undefined symbols. Then you can search for the missing functions/variables/other among the library folders of the SDK, to find what c files should be included in the project.

Regards,
Terje

[chrisgr99]

OK thanks.  Not as convenient as one might like, but at least I'll know the best way to handle it.

I'll mark these questions as answered.