////////////////////////////////////////////////////////////////////////////////
// Name: GY-521 //
// Compass GY-273 with Honeywell HMC5883L chip //
// Platform: Arduino Uno R3 //
// Created by: HARB, June 2016, GPL copyrights //
// http://robotigs.com/robotigs/includes/parts_header.php?idpart-8 //
// Connect the GY-273 to the default SDA and SCL on your Arduino UNO board. //
// Read out the result on the serial monitor. No extra resistors are needed. //
////////////////////////////////////////////////////////////////////////////////
// SET PRECOMPILER OPTIONS *****************************************************
// Define precompiler variables ------------------------------------------------
bool ledBinVal = LOW; //You can chose HIGH-on or LOW-off
//Declare variables ------------------------------------------------------------
const int HMC5883addr = 0x1E; //I2C address of the HMC5883L, 3C becomes 1E
int16_t Xaxis, Yaxis, Zaxis, Tmp, GyX, GyY, GyZ; //Values to read from compass
///Define the needed header files for the precompiler, no charge if not used ---
#include <Wire.h> //This is a very bad I²C library, but the most compatible
//END OF PRECOMPILER OPTIONS ---------------------------------------------------
void setup() { //Setup runs once ***********************************************
Serial.begin(9600); //Nothing more needed for the Serial Monitor to function
pinMode(LED_BUILTIN, OUTPUT); //Arduino boards contain an onboard LED
Wire.begin(); //Just needed once to start I²C library
Wire.beginTransmission(HMC5883addr); //Claim the I²C bus as master
Wire.write(0x02); //Mode register
Wire.write(0); //Set Continuous Measurement Mode
Wire.endTransmission(true); //Stop session and free the I²C bus
}//--(end setup )---------------------------------------------------------------
void loop() { //KEEP ON RUNNING THIS LOOP FOREVER ******************************
Wire.beginTransmission(HMC5883addr); //Claim the I²C bus as master
Wire.write(0x03); //Start writing register 0x03 = Data Output X MSB Register
Wire.endTransmission(false); //Stop session but keep bus occupied
while (digitalRead(19) == 1){} //Wait here for DRDY to be pulled low
Wire.requestFrom(HMC5883addr, 6, true); //Request a block total of 6 registers
Xaxis = Wire.read() << 8 | Wire.read(); //0x03 = Data Output X MSB Register
Zaxis = Wire.read() << 8 | Wire.read(); //0x05 = Data Output Z MSB Register
Yaxis = Wire.read() << 8 | Wire.read(); //0x07 = Data Output Y MSB Register
Serial.print("X"); Serial.print(Xaxis);
Serial.print(" | Y"); Serial.print(Yaxis);
Serial.print(" | Z"); Serial.println(Zaxis);
toggle_ledBin(); //Toggles the default on-board LED on or off
delay(1000); //You can test your own patience here
} //End of void loop() //KEEP ON RUNNING THIS LOOP FOREVER
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void toggle_ledBin(void) { //Toggles the default on-board LED on or off ********
ledBinVal = !ledBinVal; //Toggle value
digitalWrite(LED_BUILTIN, ledBinVal); //Set Arduino boards onboard LED
} //Exit toggle_ledBin ---------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
// PIN ALLOCATIONS TABLE ARDUINO UNO //
// Board -Atmel- PIN - IDE - Function - Connection ALT //
// //
// CONNECTIONS RAILS TOP LEFT: DIGITAL PWM<~> ******************************* //
// SCL - 28 - PC5 -19/A5- ADC5/SCL/PCINT13 - White cable to GY-521 TWI //
// SDA - 27 - PC4 -18/A4- ADC4/SDA/PCINT12 - Yellow cable to GY-521 TWI //
// AREF - 21 - REF - - AREF - //
// GND - 22 - GND - - GND - //
// 13 - 19 - PB5 - 13 - SCK/PCINT5 - LED_BUILTIN Arduino SPI //
// 12 - 18 - PB4 - 12 - MISO/PCINT4 - SPI //
// ~11 - 17 - PB3 - 11 - MOSI/OC2A/PCINT3 - PWM //
// ~10 - 16 - PB2 - 10 - SS/OC1B/PCINT2 - PWM //
// ~9 - 15 - PB1 - 9 - OC1A/PCINT1 - PWM //
// 8 - 14 - PB0 - 8 - PCINT0/CLK0/ICP1 - DIO //
// //
// CONNECTIONS RAILS TOP RIGHT: DIGITAL PWM<~> ****************************** //
// 7 - 13 - PD7 - 7 - PCINT23/AIN1 - DIO //
// ~6 - 12 - PD6 - 6 - PCINT22/OCA0/AIN0 - PWM //
// ~5 - 11 - PD5 - 5 - PCINT21/OC0B/T1 - PWM //
// ~4 - 6 - PD4 - 4 - PCINT20/XCK/T0 - PWM //
// ~3 - 5 - PD3 - 3 - PCINT19/OC2B/INT1 - INT //
// ~2 - 4 - PD2 - 2 - PCINT18/INT0 - INT //
// TX->1 - 3 - PD1 - 1 - PCINT17/TXD - Serial monitor TXD //
// RX<-0 - 2 - PD0 - 0 - PCINT16/RCD - Serial Monitor RCD //
// //
// CONNECTIONS RAILS BOTTOM LEFT: POWER ************************************* //
// 5V - 7 - VCC - - VCC - Output to breadboard VCC //
// RES - 1 - RES - - PCINT14/RESET - RES //
// 3.3V - - - - - //
// 5V - - - - - //
// GND - - - - - //
// GND - - - - - //
// Vin - - - - - //
// //
// CONNECTIONS RAILS BOTTOM RIGHT: ANALOG IN ******************************** //
// A0 - 23 - PC0 -A0/14- ADC0/PCINT8 - ADC //
// A1 - 24 - PC1 -A1/15- ADC1/PCINT9 - ADC //
// A2 - 25 - PC2 -A2/16- ADC2/PCINT10 - ADC //
// A3 - 26 - PC3 -A3/17- ADC3/PCINT12 - ADC //
// A4 - 27 - PC4 -A4/18- ADC4/SDA/PCINT12 - TWI //
// A5 - 28 - PC5 -A5/19- ADC5/SCL/PCINT13 - TWI //
////////////////////////////////////////////////////////////////////////////////
// EEPROM MEMORY MAP: //
// Start End Number Description //
// 0000 0000 1 Never use this memory location to be AVR compatible //
////////////////////////////////////////////////////////////////////////////////
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