[En-Nut-Discussion] Microchip Pic Support

[Harald Kipp]

Hi Chris,

On 05.06.2012 15:09, Chris Nighswonger wrote: 
> Is there any chance that Ethernut will compile under the present tools
> available for Microchip pic development?
> 
> In particular I'm interested in the possibility of running Ethernut on the
> PIC32 series. The Microchip C compiler for this series is ANSI C compliant
> fwiw.

The Nut/OS source code is quite conservative in using compiler features. If the Microchip compiler doesn't require too many exceptions from C89, compiling the code shouldn't be a big problem. Porting the kernel is no big deal either. The basic requirements are the context switching routines, a system timer interrupt and the runtime initialization. The latter can be taken from existing examples, as long as they are compatible with the BSD license. Typically it takes 1 to 2 weeks to port the kernel to a new CPU.

However, Nut/OS is not just a kernel, but a full operating system. To make use of its features, a lot of I/O driver routines need to be written. It often takes several weeks until a stable state is reached.

Of course, one may simply port the kernel and a few basic I/Os, let's say Ethernet and RS232. But I'm quite sure, that potential PIC users will immediately start asking for MMC, RTC, serial Flash and may soon become disappointed by a half way port. In the end all the hard work may slowly become outdated, if there's not sufficient support. Anyway, I think I can state the following in the name of all major contributors: We like to support more platforms in order to attract more users.

I just want to point out, that it takes significantly more effort to port Nut/OS to a new CPU family than this may be the case with other tiny OSes.

Regards,

Harald