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1

Hi,
I'm using Max31865 and Mega and would like to have the MAX31865_2WIRE, MAX31865_3WIRE and
MAX31865_4WIRE a variable in arduino sketch. This is to read jumper pins and then start the max with
the jumper vales.
program staement: max.begin(MAX31865_4WIRE);
would like to use variable
JMP_WIRE : max.begin(JMP_WIRE);

How to define JMP_WIRE in arduino code?

I'm using Adafruit MAX31865 and in the Header file MAX31865_4WIRE is
typedef enum max31865_numwires {
MAX31865_2WIRE = 0,
MAX31865_3WIRE = 1,
MAX31865_4WIRE = 0
} max31865_numwires_t;

I tried a few things in failure, need better understanding of C

How can I use a variable name in arduino to represent MAX31865_[4,3,2]WIRE ?
Thanks,
Keith

2

Define the variable as:

max31865_numwires_t num_wires = MAX31865_2WIRE;

Then you can call the begin method this way:

max.begin(num_wires);
3

OK, thanks. Will try it. I'm confused though what is the variable type num_wires ?
Also how does arduino know that I'm referencing max with:
max31865_numwires_t num_wires = MAX31865_2WIRE;

do I need to use max.max31865_numwires_t num_wires = MAX31865_2WIRE;

the max is instantiated: Adafruit_MAX31865 max = Adafruit_MAX31865(53, 51, 50, 52);

Thanks for the quick answer and your patience,
Keith

4

typedef enum max31865_numwires {
MAX31865_2WIRE = 0,
MAX31865_3WIRE = 1,
MAX31865_4WIRE = 0
} max31865_numwires_t;

This defines a type max31865_numwires_t. The _t at the end is a clue to tell you that it's a type. (The compiler doesn't care.)

So just the same as int i; creates an integer called i, max31865_numwires_t z creates a numwires called z.

You don't put max. in front of it as this is defined outside of the class.

5

Tell us what you are REALLY trying to do. Those values affect how the code is compiled as well as the run-time behavior. You can't change them at run time.