Hi, I`ve just started experimenting with LV on Arduino and run into difficulties reading the heading from an HMC6352 breakbout board.
I can read the device no problem using the following Arduino code:
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#include <Wire.h>
int HMC6352Address = 0x42;
// This is calculated in the setup() function
int slaveAddress;
int ledPin = 13;
boolean ledState = false;
byte headingData[2];
int i, headingValue;
void setup()
{
// Shift the device's documented slave address (0x42) 1 bit right
// This compensates for how the TWI library only wants the
// 7 most significant bits (with the high bit padded with 0)
slaveAddress = HMC6352Address >> 1; // This results in 0x21 as the address to pass to TWI
Serial.begin(9600);
pinMode(ledPin, OUTPUT); // Set the LED pin as output
Wire.begin();
}
void loop()
{
// Flash the LED on pin 13 just to show that something is happening
// Also serves as an indication that we're not "stuck" waiting for TWI data
ledState = !ledState;
if (ledState) {
digitalWrite(ledPin,HIGH);
}
else
{
digitalWrite(ledPin,LOW);
}
// Send a "A" command to the HMC6352
// This requests the current heading data
Wire.beginTransmission(slaveAddress);
Wire.send("A"); // The "Get Data" command
Wire.endTransmission();
delay(10); // The HMC6352 needs at least a 70us (microsecond) delay
// after this command. Using 10ms just makes it safe
// Read the 2 heading bytes, MSB first
// The resulting 16bit word is the compass heading in 10th's of a degree
// For example: a heading of 1345 would be 134.5 degrees
Wire.requestFrom(slaveAddress, 2); // Request the 2 byte heading (MSB comes first)
i = 0;
while(Wire.available() && i < 2)
{
headingData = Wire.receive();
i++;
}
headingValue = headingData[0]*256 + headingData[1]; // Put the MSB and LSB together
Serial.print("Current heading: ");
Serial.print(int (headingValue / 10)); // The whole number part of the heading
Serial.print(".");
Serial.print(int (headingValue % 10)); // The fractional part of the heading
Serial.println(" degrees");
delay(500);
}
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But I keep getting a 5003 error when trying to read it using the attached sketch, would appreciate and advice.
James
