Re: Porting to Cortex-M0+


Piotr Mienkowski <Piotr.Mienkowski@...>
 

Hi,

I have the same problem. I would like to add support for Atmel SAM E70 chip (Cortex-M7) and was thinking that using the header files provided by Atmel as part of their ASF would make the job much, much easier.

Euan, did you already add files to ext/hal/ folder? Have you talked to Maureen Helm, the ARM architecture maintainer? Should we agree on folder structure so support for future Atmel chips can be easily added?

My thoughts:
I think we should only add header files that define register access and do not add any device drivers. While header files are valuable the Atmel implementation of device drivers looks low quality, at least the SAM E70 package. The way API is written is not directly useful for any serious development, neither it follows CMSIS standard. While some drivers look good, some are incomplete and some are buggy. We would need to fix them and cooperate with Atmel to push changes upstream. I reckon using third party source code which is not maintained in open source model is not a viable long term solution. Not mentioning the fact that device drivers will have to be tightly integrated with Zephyr kernel. I believe it's easier to write our own drivers from scratch. Anyway, that's only my opinion.

The text of SAM Software Package License included in the source code (and header files) looks actually very permissive but IANAL, also the ext/hal/ folder has already a selection of proprietary code with similar licenses. In any case we should probably get an official green light from someone.

Cheers,
Piotr

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