Em 22/7/2010 12:00, Matt Rhys-Roberts escreveu:
> Please can someone faimilar with C kindly help clear up my confusion here?
>
> I'm declaring a couple of SPI function prototypes, see below. Not =

> wishing to waste too much time testing awkward things, shouldn't the =

> common variables (sync_mode, bus_mode etc.) be specified more uniquely =

> for each SPI channel? Will the following, although it compiles ok, cause =

> ambiguity when it comes to execution? I can't tell whether prototyping a =

> function is the same as declaring a variable by name, nor how it's =

> allocating the names following "unsigned char".
>
> Many thanks,
> Matt
>
>
>
> void OpenSPI1
> (
> unsigned char sync_mode,
> unsigned char bus_mode,
> unsigned char smp_phase
> );
> unsigned char WriteSPI1(unsigned char data_out );
>
> void OpenSPI2
> (
> unsigned char sync_mode,
> unsigned char bus_mode,
> unsigned char smp_phase
> );
> unsigned char WriteSPI2(unsigned char data_out );
>
> void Open1USART
> (
> unsigned char config,
> unsigned int spbrg
> );

Why don't you pass the port as an argument to the functions?
Instead of duplicating a lot of code, just duplicate and select between
the code that access the hardware?

Or you could do as in desktop systems, OpenSPI takes the port number and
returns a handle which must be passed to the other functions or -1 if it
fails?

This way you could share the SPI ports between threads (if you are using
a RTOS). I do it this way in my designs, for SPI, USART, etc.


Isaac

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