Svenska ElektronikForumet

Kod: Markera allt

*/
#include <math.h> // (no semicolon)
//// VARS
byte CLK_pin = 8;
byte EN_pin = 9;
byte DIO_pin = 10;

int X_Data = 0;
int Y_Data = 0;
int angle;

//// FUNCTIONS

void ShiftOut(int Value, int BitsCount) {
for(int i = BitsCount; i >= 0; i--) {
digitalWrite(CLK_pin, LOW);
if ((Value & 1 << i) == ( 1 << i)) {
digitalWrite(DIO_pin, HIGH);
//Serial.print("1");
}
else {
digitalWrite(DIO_pin, LOW);
//Serial.print("0");
}
digitalWrite(CLK_pin, HIGH);
delayMicroseconds(1);
}
//Serial.print(" ");
}

int ShiftIn(int BitsCount) {
int ShiftIn_result;
ShiftIn_result = 0;
pinMode(DIO_pin, INPUT);
for(int i = BitsCount; i >= 0; i--) {
digitalWrite(CLK_pin, HIGH);
delayMicroseconds(1);
if (digitalRead(DIO_pin) == HIGH) {
ShiftIn_result = (ShiftIn_result << 1) + 1;
//Serial.print("x");
}
else {
ShiftIn_result = (ShiftIn_result << 1) + 0;
//Serial.print("_");
}
digitalWrite(CLK_pin, LOW);
delayMicroseconds(1);
}
//Serial.print(":");

// below is difficult to understand:
// if bit 11 is Set the value is negative
// the representation of negative values you
// have to add B11111000 in the upper Byte of
// the integer.
// see: http://en.wikipedia.org/wiki/Two%27s_complement
if ((ShiftIn_result & 1 << 11) == 1 << 11) {
ShiftIn_result = (B11111000 << 8) | ShiftIn_result;
}


return ShiftIn_result;
}

void HM55B_Reset() {
pinMode(DIO_pin, OUTPUT);
digitalWrite(EN_pin, LOW);
ShiftOut(B0000, 3);
digitalWrite(EN_pin, HIGH);
}

void HM55B_StartMeasurementCommand() {
pinMode(DIO_pin, OUTPUT);
digitalWrite(EN_pin, LOW);
ShiftOut(B1000, 3);
digitalWrite(EN_pin, HIGH);
}

int HM55B_ReadCommand() {
int result = 0;
pinMode(DIO_pin, OUTPUT);
digitalWrite(EN_pin, LOW);
ShiftOut(B1100, 3);
result = ShiftIn(3);
return result;
}


void setup() {
Serial.begin(115200);
pinMode(EN_pin, OUTPUT);
pinMode(CLK_pin, OUTPUT);
pinMode(DIO_pin, INPUT);

HM55B_Reset();
}

void loop() {
HM55B_StartMeasurementCommand(); // necessary!!
delay(40); // the data is 40ms later ready
Serial.print(HM55B_ReadCommand()); // read data and print Status
Serial.print(" ");
X_Data = ShiftIn(11); // Field strength in X
Y_Data = ShiftIn(11); // and Y direction
Serial.print(X_Data); // print X strength
Serial.print(" ");
Serial.print(Y_Data); // print Y strength
Serial.print(" ");
digitalWrite(EN_pin, HIGH); // ok deselect chip
angle = 180 * (atan2(-1 * Y_Data , X_Data) / M_PI); // angle is atan( -y/x) !!!
Serial.print(angle); // print angle
Serial.println("");

}