Re: [avr-libc-dev] Determine defined port

[E. Weddington]

Harald Kipp wrote:

> Hi all,
>
> I stumbled over the following pre-processor problem.
>
> Somewhere in an include file there's a macro
>
>   #define MY_PORT  PORTC
>
> User's should be able to adapt the program to their hardware
> be simply changing this include file.
>
> To make the code independent from the specified port,
> I need something like
>
>   #if (MY_PORT == PORTC)
>   /* Do something PORTC specific, like disabling XMEM */
>   #endif
>   sbi(MY_PORT, 7);
>
> Obviously this won't work, because PORTC is an already dereferenced
> volatile pointer. No chance to retrieve the pointer address, right?
Actually you *can* retrieve the pointer address. The register names can 
be used as variables, so you can take the address of it like so:

&PORTC

HTH
Eric