using macros for configuration

Question

I'm writing firmware in C for an embedded processor. I want to have all the configuration information in one header file called config.h. This is causing problems with the ADC initialization, where simple #defines won't do the trick. Right now the code is like so:

config.h

#define NUMBER_OF_POTS  1
#define POT_1_CHANNEL  27

adc.c

#define MAKE_CSS(channel) _CSS##channel
#define CALL_MAKE_CSS(channel) MAKE_CSS(channel)

void initialize_adc() {
   CALL_MAKE_CSS(POT_1_CHANNEL);
}

What I want to do is not have to touch adc.c if I change config.h to:

#define NUMBER_OF_POTS  2
#define POT_1_CHANNEL  27
#define POT_2_CHANNEL  29

adc.c should just automatically add a second CALL_MAKE_CSS with some macro trickery.

I guess the question is: is there a trick that gives you for loop capability with a macro?

Thanks,

Steve.

Answer 1

I didn't test this:

// config.h

#define NUMBER_OF_POTS  2
extern int pots[];

// config.c

int pots[NUMBER_OF_POTS] = {
    27,
    29
};


// adc.c

void initialize_adc() {
    for (int i = 0; i < NUMBER_OF_POTS; i++) {
        CALL_MAKE_CSS(pots[i]);
    }
}