Updated examples

Author: oclyke

examples/MPU9250BasicAHRS_I2C/MPU9250BasicAHRS_I2C.ino

@@ -49,12 +49,12 @@ Adafruit_PCD8544 display = Adafruit_PCD8544(9, 8, 7, 5, 6);
 int intPin = 12; // These can be changed, 2 and 3 are the Arduinos ext int pins
 int myLed = 13; // Set up pin 13 led for toggling
 
-#define I2C_clock 400000
-#define I2C_port Wire
+#define I2Cclock 400000
+#define I2Cport Wire
 #define MPU9250_ADDRESS MPU9250_ADDRESS_AD0 // Use either this line or the next to select which I2C address your device is using
 //#define MPU9250_ADDRESS MPU9250_ADDRESS_AD1
 
-MPU9250 myIMU(MPU9250_ADDRESS, I2C_port, I2C_clock);
+MPU9250 myIMU(MPU9250_ADDRESS, I2Cport, I2Cclock);
 
 void setup()
 {

examples/MPU9250BasicAHRS_SPI/MPU9250BasicAHRS_SPI.ino

@@ -42,7 +42,17 @@ Adafruit_PCD8544 display = Adafruit_PCD8544(9, 8, 7, 5, 6);
 #define AHRS true // Set to false for basic data read
 #define SERIAL_DEBUG true // Set to true to get Serial output for debugging
 
-MPU9250 myIMU = MPU9250(2); // Using digital pin to for chip select in demo
+#define SPIport SPI
+#define CSpin 2
+#define SPIrate 1000000
+MPU9250 myIMU = MPU9250(CSpin, SPIport, SPIrate); // Using digital pin to for chip select in demo
+
+
+// Because of the way this library is written you still need to send SOME address - 
+// but in SPI mode it is not used, so I chose over 9000 - By the way if you look closely
+// there will be a truncation warning during compilation because 9001 is too large for 
+// the parameter's type.
+#define MPU9250_ADDRESS 9001
 
 void setup()
 {

src/MPU9250.cpp

@@ -5,7 +5,7 @@
 //====== and temperature data
 //==============================================================================
 
-MPU9250::MPU9250( int8_t csPin, SPIClass &spiInterface )
+MPU9250::MPU9250( int8_t csPin, SPIClass &spiInterface, uint32_t spi_freq )
 {
 // Use hardware SPI communication
  // If used with sparkfun breakout board
@@ -17,6 +17,8 @@ MPU9250::MPU9250( int8_t csPin, SPIClass &spiInterface )
 _spi = &spiInterface;
 _wire = NULL;
 
+_interfaceSpeed = spi_freq;
+
  _spi->begin();
  pinMode(_csPin, OUTPUT);
  deselect();
@@ -27,10 +29,12 @@ MPU9250::MPU9250( uint8_t address, TwoWire &wirePort, uint32_t clock_frequency )
 _wire = &wirePort;
 _spi = NULL;
 
+_interfaceSpeed = clock_frequency;
+
 _csPin = NOT_SPI;// Used to tell the library that the sensor is using I2C
 
 _wire->begin();
-_wire->setClock(clock_frequency);
+_wire->setClock(_interfaceSpeed);
 }
 
 void MPU9250::getMres()
@@ -612,8 +616,8 @@ void MPU9250::magCalMPU9250(float * bias_dest, float * scale_dest)
  uint16_t ii = 0, sample_count = 0;
  int32_t mag_bias[3] = {0, 0, 0},
  mag_scale[3] = {0, 0, 0};
- int16_t mag_max[3] = {0x8000, 0x8000, 0x8000},
- mag_min[3] = {0x7FFF, 0x7FFF, 0x7FFF},
+ int16_t mag_max[3] = {-32768, -32768, -32768},// Wrote out decimal (signed) values to remove a conversion warning
+ mag_min[3] = {32767, 32767, 32767},
  mag_temp[3] = {0, 0, 0};
 
  // Make sure resolution has been calculated
@@ -715,7 +719,7 @@ uint8_t MPU9250::writeByteSPI(uint8_t registerAddress, uint8_t writeData)
 {
  uint8_t returnVal;
 
- _spi->beginTransaction(SPISettings(SPI_DATA_RATE, MSBFIRST, SPI_MODE));
+ _spi->beginTransaction(SPISettings(_interfaceSpeed, MSBFIRST, SPI_MODE));
  select();
 
  _spi->transfer(registerAddress);
@@ -733,12 +737,14 @@ uint8_t MPU9250::writeByteSPI(uint8_t registerAddress, uint8_t writeData)
 uint8_t MPU9250::writeByteWire(uint8_t deviceAddress, uint8_t registerAddress,
  uint8_t data)
 {
- _wire->beginTransmission(deviceAddress); // Initialize the Tx buffer
- _wire->write(registerAddress); // Put slave register address in Tx buffer
- _wire->write(data); // Put data in Tx buffer
- _wire->endTransmission(); // Send the Tx buffer
- // TODO: Fix this to return something meaningful
- return NULL;
+_wire->setClock(_interfaceSpeed);// Reset to the desired speed, in case other devices required a slowdown
+	_wire->beginTransmission(deviceAddress); // Initialize the Tx buffer
+	_wire->write(registerAddress); // Put slave register address in Tx buffer
+	_wire->write(data); // Put data in Tx buffer
+	_wire->endTransmission(); // Send the Tx buffer
+ // TODO: Fix this to return something meaningful
+ // return NULL; // In the meantime fix it to return the right type
+ return 0;
 }
 
 // Read a byte from given register on device. Calls necessary SPI or I2C

src/MPU9250.h

@@ -180,7 +180,6 @@
 #define READ_FLAG 0x80
 #define NOT_SPI -1
 #define SPI_DATA_RATE 1000000 // 1MHz is the max speed of the MPU-9250
-//#define SPI_DATA_RATE 1000000 // 1MHz is the max speed of the MPU-9250
 #define SPI_MODE SPI_MODE3
 
 class MPU9250
@@ -212,9 +211,14 @@ class MPU9250
  M_100HZ = 0x06 // 100 Hz continuous magnetometer
  };
 
- uint8_t _I2Caddr = MPU9250_ADDRESS_AD0;// Use AD0 by default
- SPIClass * _spi;// Allows for use of different SPI ports
+ 
  TwoWire * _wire;// Allows for use of various I2C ports
+ uint8_t _I2Caddr = MPU9250_ADDRESS_AD0;// Use AD0 by default
+
+	SPIClass * _spi;// Allows for use of different SPI ports
+ int8_t _csPin; // SPI chip select pin
+
+ uint32_t _interfaceSpeed;// Stores the desired I2C or SPi clock rate
 
  // TODO: Add setter methods for this hard coded stuff
  // Specify sensor full scale
@@ -226,8 +230,8 @@ class MPU9250
  // 2 for 8 Hz, 6 for 100 Hz continuous magnetometer data read
  uint8_t Mmode = M_8HZ;
 
- // SPI chip select pin
- int8_t _csPin;
+ 
+ 
 
  uint8_t writeByteWire(uint8_t, uint8_t, uint8_t);
  uint8_t writeByteSPI(uint8_t, uint8_t);
@@ -270,7 +274,7 @@ class MPU9250
  int16_t accelCount[3];
 
  // Public method declarations
- MPU9250( int8_t _csPin, SPIClass &spiInterface = SPI);
+ MPU9250( int8_t _csPin, SPIClass &spiInterface = SPI, uint32_t spi_freq = SPI_DATA_RATE);
  MPU9250( uint8_t address = MPU9250_ADDRESS_AD0, TwoWire &wirePort = Wire, uint32_t clock_frequency = 100000 );
  void getMres();
  void getGres();