Diff: main.cpp

Revision:

0:efb1550773f1

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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Fri Mar 19 21:59:25 2021 +0000
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+/* ICM20948 Basic Example Code
+ by: Kris Winer
+ date: April 1, 2014
+ license: Beerware - Use this code however you'd like. If you
+ find it useful you can buy me a beer some time.
+ Modified by Brent Wilkins July 19, 2016
+ Demonstrate basic ICM20948 functionality including parameterizing the register
+ addresses, initializing the sensor, getting properly scaled accelerometer,
+ gyroscope, and magnetometer data out. Added display functions to allow display
+ to on breadboard monitor. Addition of 9 DoF sensor fusion using open source
+ Madgwick and Mahony filter algorithms. Sketch runs on the 3.3 V 8 MHz Pro Mini
+ and the Teensy 3.1.
+ SDA and SCL should have external pull-up resistors (to 3.3V).
+ 10k resistors are on the EMSENSR-9250 breakout board.
+ Hardware setup:
+ ICM20948 Breakout --------- Arduino
+ VDD ---------------------- 3.3V
+ VDDI --------------------- 3.3V
+ SDA ----------------------- A4
+ SCL ----------------------- A5
+ GND ---------------------- GND
+ */
+
+#include "AHRSAlgorithms.h"
+#include "ICM20948.h"
+
+#define AHRS false         // Set to false for basic data read
+#define SerialDebug true  // Set to true to get Serial output for debugging
+
+
+ICM20948 myIMU;
+
+void setup()
+{
+  Wire.begin();
+  // TWBR = 12;  // 400 kbit/sec I2C speed
+  Serial.begin(115200);
+  while(!Serial) delay(10);
+    
+  pinMode(myLed, OUTPUT);
+  digitalWrite(myLed, HIGH);
+
+  // Reset ICM20948
+  myIMU.writeByte(ICM20948_ADDRESS, PWR_MGMT_1, READ_FLAG);
+  delay(100);
+  myIMU.writeByte(ICM20948_ADDRESS, PWR_MGMT_1, 0x01);
+  delay(100);
+  
+  // Read the WHO_AM_I register, this is a good test of communication
+  byte c = myIMU.readByte(ICM20948_ADDRESS, WHO_AM_I_ICM20948);
+  Serial.print(F("ICM20948 I AM 0x"));
+  Serial.print(c, HEX);
+  Serial.print(F(" I should be 0x"));
+  Serial.println(0xEA, HEX);
+
+  if (c == 0xEA) // WHO_AM_I should always be 0x71
+  {
+    Serial.println(F("ICM20948 is online..."));
+
+    // Start by performing self test and reporting values
+    myIMU.ICM20948SelfTest(myIMU.selfTest);
+    Serial.print(F("x-axis self test: acceleration trim within : "));
+    Serial.print(myIMU.selfTest[0],1); Serial.println("% of factory value");
+    Serial.print(F("y-axis self test: acceleration trim within : "));
+    Serial.print(myIMU.selfTest[1],1); Serial.println("% of factory value");
+    Serial.print(F("z-axis self test: acceleration trim within : "));
+    Serial.print(myIMU.selfTest[2],1); Serial.println("% of factory value");
+    Serial.print(F("x-axis self test: gyration trim within : "));
+    Serial.print(myIMU.selfTest[3],1); Serial.println("% of factory value");
+    Serial.print(F("y-axis self test: gyration trim within : "));
+    Serial.print(myIMU.selfTest[4],1); Serial.println("% of factory value");
+    Serial.print(F("z-axis self test: gyration trim within : "));
+    Serial.print(myIMU.selfTest[5],1); Serial.println("% of factory value");
+
+    // Calibrate gyro and accelerometers, load biases in bias registers
+    myIMU.calibrateICM20948(myIMU.gyroBias, myIMU.accelBias);
+
+    myIMU.initICM20948();
+    // Initialize device for active mode read of acclerometer, gyroscope, and
+    // temperature
+    Serial.println("ICM20948 initialized for active data mode....");
+
+    // Read the WHO_AM_I register of the magnetometer, this is a good test of
+    // communication
+    byte d = myIMU.readByte(AK09916_ADDRESS, WHO_AM_I_AK09916);
+    Serial.print("AK8963 ");
+    Serial.print("I AM 0x");
+    Serial.print(d, HEX);
+    Serial.print(" I should be 0x");
+    Serial.println(0x09, HEX);
+
+    if (d != 0x09)
+    {
+      // Communication failed, stop here
+      Serial.println(F("Communication with magnetometer failed, abort!"));
+      Serial.flush();
+      abort();
+    }
+
+    // Get magnetometer calibration from AK8963 ROM
+    myIMU.initAK09916();
+    // Initialize device for active mode read of magnetometer
+    Serial.println("AK09916 initialized for active data mode....");
+    
+    /*
+    if (SerialDebug)
+    {
+      //  Serial.println("Calibration values: ");
+      Serial.print("X-Axis factory sensitivity adjustment value ");
+      Serial.println(myIMU.factoryMagCalibration[0], 2);
+      Serial.print("Y-Axis factory sensitivity adjustment value ");
+      Serial.println(myIMU.factoryMagCalibration[1], 2);
+      Serial.print("Z-Axis factory sensitivity adjustment value ");
+      Serial.println(myIMU.factoryMagCalibration[2], 2);
+    }
+    */
+
+    // Get sensor resolutions, only need to do this once
+    myIMU.getAres();
+    myIMU.getGres();
+    myIMU.getMres();
+
+    // The next call delays for 4 seconds, and then records about 15 seconds of
+    // data to calculate bias and scale.
+    myIMU.magCalICM20948(myIMU.magBias, myIMU.magScale);
+    Serial.println("AK09916 mag biases (mG)");
+    Serial.println(myIMU.magBias[0]);
+    Serial.println(myIMU.magBias[1]);
+    Serial.println(myIMU.magBias[2]);
+
+    Serial.println("AK09916 mag scale (mG)");
+    Serial.println(myIMU.magScale[0]);
+    Serial.println(myIMU.magScale[1]);
+    Serial.println(myIMU.magScale[2]);
+    delay(2000); // Add delay to see results before serial spew of data
+  } // if (c == 0x71)
+  else
+  {
+    Serial.print("Could not connect to ICM20948: 0x");
+    Serial.println(c, HEX);
+
+    // Communication failed, stop here
+    Serial.println(F("Communication failed, abort!"));
+    Serial.flush();
+    abort();
+  }
+}
+
+void loop()
+{
+  // If intPin goes high, all data registers have new data
+  // On interrupt, check if data ready interrupt
+  if (myIMU.readByte(ICM20948_ADDRESS, INT_STATUS_1) & 0x01)
+  {
+    myIMU.readAccelData(myIMU.accelCount);  // Read the x/y/z adc values
+
+    // Now we'll calculate the accleration value into actual g's
+    // This depends on scale being set
+    myIMU.ax = (float)myIMU.accelCount[0] * myIMU.aRes; // - myIMU.accelBias[0];
+    myIMU.ay = (float)myIMU.accelCount[1] * myIMU.aRes; // - myIMU.accelBias[1];
+    myIMU.az = (float)myIMU.accelCount[2] * myIMU.aRes; // - myIMU.accelBias[2];
+
+    myIMU.readGyroData(myIMU.gyroCount);  // Read the x/y/z adc values
+
+    // Calculate the gyro value into actual degrees per second
+    // This depends on scale being set
+    myIMU.gx = (float)myIMU.gyroCount[0] * myIMU.gRes;
+    myIMU.gy = (float)myIMU.gyroCount[1] * myIMU.gRes;
+    myIMU.gz = (float)myIMU.gyroCount[2] * myIMU.gRes;
+
+    myIMU.readMagData(myIMU.magCount);  // Read the x/y/z adc values
+
+    // Calculate the magnetometer values in milliGauss
+    // Include factory calibration per data sheet and user environmental
+    // corrections
+    // Get actual magnetometer value, this depends on scale being set
+    myIMU.mx = (float)myIMU.magCount[0] * myIMU.mRes - myIMU.magBias[0];
+    myIMU.my = (float)myIMU.magCount[1] * myIMU.mRes - myIMU.magBias[1];
+    myIMU.mz = (float)myIMU.magCount[2] * myIMU.mRes - myIMU.magBias[2];
+  } // if (readByte(ICM20948_ADDRESS, INT_STATUS) & 0x01)
+
+  // Must be called before updating quaternions!
+  myIMU.updateTime();
+
+  // Sensors x (y)-axis of the accelerometer is aligned with the y (x)-axis of
+  // the magnetometer; the magnetometer z-axis (+ down) is opposite to z-axis
+  // (+ up) of accelerometer and gyro! We have to make some allowance for this
+  // orientationmismatch in feeding the output to the quaternion filter. For the
+  // ICM20948, we have chosen a magnetic rotation that keeps the sensor forward
+  // along the x-axis just like in the LSM9DS0 sensor. This rotation can be
+  // modified to allow any convenient orientation convention. This is ok by
+  // aircraft orientation standards! Pass gyro rate as rad/s
+  MahonyQuaternionUpdate(myIMU.ax, myIMU.ay, myIMU.az, myIMU.gx * DEG_TO_RAD,
+                         myIMU.gy * DEG_TO_RAD, myIMU.gz * DEG_TO_RAD, myIMU.my,
+                         myIMU.mx, myIMU.mz, myIMU.deltat);
+
+  if (!AHRS)
+  {
+    myIMU.delt_t = millis() - myIMU.count;
+    if (myIMU.delt_t > 500)
+    {
+      if(SerialDebug)
+      {
+        // Print acceleration values in milligs!
+        Serial.print("X-acceleration: "); Serial.print(1000 * myIMU.ax);
+        Serial.print(" mg ");
+        Serial.print("Y-acceleration: "); Serial.print(1000 * myIMU.ay);
+        Serial.print(" mg ");
+        Serial.print("Z-acceleration: "); Serial.print(1000 * myIMU.az);
+        Serial.println(" mg ");
+
+        // Print gyro values in degree/sec
+        Serial.print("X-gyro rate: "); Serial.print(myIMU.gx, 3);
+        Serial.print(" degrees/sec ");
+        Serial.print("Y-gyro rate: "); Serial.print(myIMU.gy, 3);
+        Serial.print(" degrees/sec ");
+        Serial.print("Z-gyro rate: "); Serial.print(myIMU.gz, 3);
+        Serial.println(" degrees/sec");
+
+        // Print mag values in degree/sec
+        Serial.print("X-mag field: "); Serial.print(myIMU.mx);
+        Serial.print(" mG ");
+        Serial.print("Y-mag field: "); Serial.print(myIMU.my);
+        Serial.print(" mG ");
+        Serial.print("Z-mag field: "); Serial.print(myIMU.mz);
+        Serial.println(" mG");
+
+        myIMU.tempCount = myIMU.readTempData();  // Read the adc values
+        // Temperature in degrees Centigrade
+        myIMU.temperature = ((float) myIMU.tempCount) / 333.87 + 21.0;
+        // Print temperature in degrees Centigrade
+        Serial.print("Temperature is ");  Serial.print(myIMU.temperature, 1);
+        Serial.println(" degrees C");
+      }
+
+      myIMU.count = millis();
+      digitalWrite(myLed, !digitalRead(myLed));  // toggle led
+    } // if (myIMU.delt_t > 500)
+  } // if (!AHRS)
+  else
+  {
+    // Serial print and/or display at 0.5 s rate independent of data rates
+    myIMU.delt_t = millis() - myIMU.count;
+
+    // update LCD once per half-second independent of read rate
+    if (myIMU.delt_t > 500)
+    {
+      if(SerialDebug)
+      {
+        Serial.print("ax = ");  Serial.print((int)1000 * myIMU.ax);
+        Serial.print(" ay = "); Serial.print((int)1000 * myIMU.ay);
+        Serial.print(" az = "); Serial.print((int)1000 * myIMU.az);
+        Serial.println(" mg");
+
+        Serial.print("gx = ");  Serial.print(myIMU.gx, 2);
+        Serial.print(" gy = "); Serial.print(myIMU.gy, 2);
+        Serial.print(" gz = "); Serial.print(myIMU.gz, 2);
+        Serial.println(" deg/s");
+
+        Serial.print("mx = ");  Serial.print((int)myIMU.mx);
+        Serial.print(" my = "); Serial.print((int)myIMU.my);
+        Serial.print(" mz = "); Serial.print((int)myIMU.mz);
+        Serial.println(" mG");
+
+        Serial.print("q0 = ");  Serial.print(*getQ());
+        Serial.print(" qx = "); Serial.print(*(getQ() + 1));
+        Serial.print(" qy = "); Serial.print(*(getQ() + 2));
+        Serial.print(" qz = "); Serial.println(*(getQ() + 3));
+      }
+
+// Define output variables from updated quaternion---these are Tait-Bryan
+// angles, commonly used in aircraft orientation. In this coordinate system,
+// the positive z-axis is down toward Earth. Yaw is the angle between Sensor
+// x-axis and Earth magnetic North (or true North if corrected for local
+// declination, looking down on the sensor positive yaw is counterclockwise.
+// Pitch is angle between sensor x-axis and Earth ground plane, toward the
+// Earth is positive, up toward the sky is negative. Roll is angle between
+// sensor y-axis and Earth ground plane, y-axis up is positive roll. These
+// arise from the definition of the homogeneous rotation matrix constructed
+// from quaternions. Tait-Bryan angles as well as Euler angles are
+// non-commutative; that is, the get the correct orientation the rotations
+// must be applied in the correct order which for this configuration is yaw,
+// pitch, and then roll.
+// For more see
+// http://en.wikipedia.org/wiki/Conversion_between_quaternions_and_Euler_angles
+// which has additional links.
+      myIMU.yaw   = atan2(2.0f * (*(getQ()+1) * *(getQ()+2) + *getQ()
+                    * *(getQ()+3)), *getQ() * *getQ() + *(getQ()+1)
+                    * *(getQ()+1) - *(getQ()+2) * *(getQ()+2) - *(getQ()+3)
+                    * *(getQ()+3));
+      myIMU.pitch = -asin(2.0f * (*(getQ()+1) * *(getQ()+3) - *getQ()
+                    * *(getQ()+2)));
+      myIMU.roll  = atan2(2.0f * (*getQ() * *(getQ()+1) + *(getQ()+2)
+                    * *(getQ()+3)), *getQ() * *getQ() - *(getQ()+1)
+                    * *(getQ()+1) - *(getQ()+2) * *(getQ()+2) + *(getQ()+3)
+                    * *(getQ()+3));
+      myIMU.pitch *= RAD_TO_DEG;
+      myIMU.yaw   *= RAD_TO_DEG;
+
+      // Declination of SparkFun Electronics (40°05'26.6"N 105°11'05.9"W) is
+      //    8° 30' E  ± 0° 21' (or 8.5°) on 2016-07-19
+      // - http://www.ngdc.noaa.gov/geomag-web/#declination
+      myIMU.yaw  -= 8.5;
+      myIMU.roll *= RAD_TO_DEG;
+
+      if(SerialDebug)
+      {
+        Serial.print("Yaw, Pitch, Roll: ");
+        Serial.print(myIMU.yaw, 2);
+        Serial.print(", ");
+        Serial.print(myIMU.pitch, 2);
+        Serial.print(", ");
+        Serial.println(myIMU.roll, 2);
+
+        Serial.print("rate = ");
+        Serial.print((float)myIMU.sumCount / myIMU.sum, 2);
+        Serial.println(" Hz");
+      }
+
+      myIMU.count = millis();
+      myIMU.sumCount = 0;
+      myIMU.sum = 0;
+    } // if (myIMU.delt_t > 500)
+  } // if (AHRS)
+}
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