ansi C unions on arduino
After some time of googling, i found interesting solution, how to get and set pins as bits in arduino
union myunion {
struct {
unsigned int b7: 1;
unsigned int b6: 1;
unsigned int b5: 1;
unsigned int b4: 1;
unsigned int b3: 1;
unsigned int b2: 1;
unsigned int b1: 1;
unsigned int b0: 1;
};
unsigned int num;
} mu;
with this union with struct, we can read pins to 1 big number invidual bits and display it on for example - led's in binary.
mu.b0 = digitalRead(2);
mu.b1 = digitalRead(3);
mu.b2 = digitalRead(4);
mu.b3 = digitalRead(5);
mu.b4 = digitalRead(6);
mu.b5 = digitalRead(7);
mu.b6 = digitalRead(8);
mu.b7 = digitalRead(9);
and vuola, now we can get number with "mu.num" depending on HIGH pinsĀ
Serial.println(mu.num);
and in reverse, we can set "mu.num = 127" and write individual bits to pins.
digitalWrite(mu.b0);
digitalWrite(mu.b1);
digitalWrite(mu.b2);
digitalWrite(mu.b3);
digitalWrite(mu.b4);
digitalWrite(mu.b5);
digitalWrite(mu.b6);
digitalWrite(mu.b7);
whole program:
// parallel to serial
// serial to parallel
union mu1 {
struct {
unsigned int b7: 1;
unsigned int b6: 1;
unsigned int b5: 1;
unsigned int b4: 1;
unsigned int b3: 1;
unsigned int b2: 1;
unsigned int b1: 1;
unsigned int b0: 1;
};
unsigned int num;
} mu;
void setup() {
Serial.begin(9600);
}
void loop() {
mu.b0 = digitalRead(2); // switch 1
mu.b1 = digitalRead(3); // switch 2
mu.b2 = digitalRead(4); // switch 3
mu.b3 = digitalRead(5); // switch 4
mu.b4 = digitalRead(6); // switch 5
mu.b5 = digitalRead(7); // switch 6
mu.b6 = digitalRead(8); // switch 7
mu.b7 = digitalRead(9); // switch 8
Serial.println(mu.num);
delay(5000);
}
thats it. union acts as "shift in" and "shift out" register, if you set mu.num than you can read individual bits(pins) if you set pins you can read mu.num and it works then like shift in register.