Convert unsigned int to 2 unsigned char, upper and lower

[Zener]

In C, is there an easy way to do this? I am hoping yes...

[franklin97355]

Try "anding" with 0xf and then shift right 8.

[hjohnson]

This should work.

#define LOW_BYTE(x) = (x & 0xFF) //just the lower byte
#define HIGH_BYTE(x) = (x>>8) & 0xFF //make the higher byte the lower byte, then take just it.

See: http://www.arduino.cc/playground/Code/BitMath

[philba]

The shift and mask thing is pretty much the standard way of doing it. A bit faster in that it does no shifting or masking. (Not a big deal unless it inside a loop).

Code: Select all

int a;
char *alow = (char *)&a;
char *ahigh = (char *) &a+1;

void setup(){
    a = 0x0102;
    Serial.begin(9600);
    Serial.println((int)*ahigh);
    Serial.println((int)*alow);
}
void loop(){}


prints out
1
2

[Zener]

Yep, simple. Did this:

Code: Select all

unsigned int address = 0xBBAA;
unsigned char adrhigh = 0;
unsigned char adrlow = 0;

adrlow = address & 0xFF;
adrhigh = (address>>8) & 0xFF;


Works. I just wasn't sure the compiler would like me mixing types like that...

Thanks