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RTOS_SensorBoard/IMU.h

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+#ifndef IMU_H
+#define IMU_H
+
+#include <stdint.h>
+
+#define I2C_ADDRESS 0x68
+
+// MPU-6050 register addresses
+#define MPU_WHO_AM_I     0x75
+#define MPU_PWR_MGMT_1   0x6B
+#define MPU_CONFIG       0x1A
+#define MPU_ACCEL_XOUT_H 0x3B
+
+// Digital low-pass filter bandwidth (CONFIG register bits [2:0]).
+//   0 = 256 Hz gyro BW (default, noisiest)
+//   1 = 188 Hz, 2 =  98 Hz, 3 = 44 Hz, 4 = 21 Hz, 5 = 10 Hz, 6 = 5 Hz
+// Lower BW = more smoothing, more lag. 3 is a good default for 50 Hz control.
+#define IMU_DLPF_CFG     0x03
+
+// Number of back-to-back samples averaged per IMU_Read call.
+// Must be power of 2 so compiler uses shift for divide.
+#define IMU_AVG_SAMPLES  4
+
+// Conversion scales
+#define ACCEL_SCALE 16384 // for 1 G
+#define GYRO_SCALE 131 // degrees/sec
+
+// Latest sensor readings, updated on each IMU_Read call.
+// Raw signed 16-bit ADC counts (big-endian from chip, assembled).
+// Default scale factors
+//   accel: 16384 LSB/g    (+/-2 g range)
+//   gyro:  131 LSB/(deg/s) (+/-250 dps range)
+//   temp:  T_C = raw/340 + 36.53
+extern volatile int16_t IMU_AccelX;
+extern volatile int16_t IMU_AccelY;
+extern volatile int16_t IMU_AccelZ;
+extern volatile int16_t IMU_Temp;
+extern volatile int16_t IMU_GyroX;
+extern volatile int16_t IMU_GyroY;
+extern volatile int16_t IMU_GyroZ;
+
+// Initialize MPU-6050.
+// Calls I2C_Init, verifies WHO_AM_I, clears SLEEP bit to wake chip.
+// Returns 0 on success, nonzero on error (see IMU.c for codes).
+int IMU_Init(void);
+
+// Burst read all 14 sensor bytes and update IMU_* globals.
+// Returns 0 on success, nonzero on error.
+int IMU_Read(void);
+
+#endif