Mark Gottscho
A compilation of some hardware sensors and their shared programming interfaces.
Diff: MMA8451Q.h
- Revision:
- 0:8d34cc2ff388
diff -r 000000000000 -r 8d34cc2ff388 MMA8451Q.h
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/MMA8451Q.h Sun Mar 16 01:48:59 2014 +0000
@@ -0,0 +1,286 @@
+/* MMA8451Q.h
+ * Tested with mbed board: FRDM-KL46Z
+ * Author: Mark Gottscho
+ * mgottscho@ucla.edu
+ */
+
+#ifndef MMA8451Q_H
+#define MMA8451Q_H
+
+#include "mbed.h"
+#include "I2CSensor.h"
+#include "PeriodicSensor.h"
+#include "SleepableSensor.h"
+
+/**
+ * This class allows for easy control of an MMA8451Q accelerometer IC.
+ */
+class MMA8451Q : public I2CSensor, public PeriodicSensor, public SleepableSensor {
+ public:
+ /**
+ * Enumeration of allowed output data sampling rates.
+ */
+ typedef enum {
+ HZ800,
+ HZ400,
+ HZ200,
+ HZ100,
+ HZ50,
+ HZ12_5,
+ HZ6_25,
+ HZ1_56
+ } smpl_rate_t;
+
+ /**
+ * Enumeration of allowed dynamic ranges (full scale) of the accelerometer data.
+ * G2: +/- 2G (0.25 mg/level at 14b, 15.6 mg/level at 8b)
+ * G4: +/- 4G (0.5 mg/level at 14b, 31.25 mg/level at 8b)
+ * G8: +/- 8G (1.0 mg/level at 14b, 62.5 mg/level at 8b)
+ */
+ typedef enum {
+ G2,
+ G4,
+ G8
+ } scale_t;
+
+ /**
+ * @param sda the pin identifier for SDA I2C signal
+ * @param scl the pin identifier for SCL I2C signal
+ * @param i2c_addr the 8-bit I2C address for this device. Note that LSB is a don't care.
+ */
+ MMA8451Q(PinName sda, PinName scl, int i2c_addr);
+
+ /**
+ */
+ ~MMA8451Q();
+
+ /**
+ * Self-initialization to some nice preset. You must ensure the device is first deactivated using setActive().
+ */
+ void selfInit();
+
+ /**
+ * Does a soft reset of the device.
+ */
+ void reset();
+
+ //I2C specific methods
+
+ /**
+ * Implements the pure virtual method of the parent I2CSensor class.
+ * @returns the 8-bit device identifier.
+ */
+ uint8_t whoAmI();
+
+ //Device-specific methods
+
+ /**
+ * @returns true if the device is active
+ */
+ bool isActive();
+
+ /**
+ * @param activate if true, enables the device, else disables it
+ */
+ void setActive(bool activate);
+
+ /**
+ * @returns the 8-bit system mode status
+ */
+ uint8_t getSystemMode();
+
+ /**
+ * @returns true if the device is generating 14b resolution data, otherwise 8b
+ */
+ bool is14bDataEnabled();
+
+ /**
+ * @param enable if true, sets 14b data, otherwise 8b data
+ */
+ void set14bData(bool enable);
+
+ /**
+ * @returns an enumerated value corresponding to the current output data sample rate
+ */
+ smpl_rate_t getOutputDataRate();
+
+ /**
+ * @param the enumerated value corresponding to the output data sample rate to use
+ */
+ void setOutputDataRate(smpl_rate_t rate);
+
+ /**
+ * @returns an enumerated value corresponding to the full scale (range) of the output data
+ */
+ scale_t getScale();
+
+ /**
+ * @param scale sets the sample scale via the enumerated value
+ */
+ void setScale(scale_t scale);
+
+ /**
+ * Enables an interrupt output signal from the device whenever data (XYZ) is generated.
+ * @param enable Enables/disables interrupt
+ * @param pinSelect if false, INT2. if true, INT1
+ */
+ void enableDataReadyInterrupt(bool enable, bool pinSelect);
+
+
+ //Device-specific data retrieval methods
+ /**
+ * @param sampleNow if true, queries the device for the sample and returns it. if false, gets the last queried value.
+ * The latter is preferred if this object is set up to sample using interrupts.
+ * @returns a 14-bit value representing the latest data sample for the X dimension, centered at 0.
+ */
+ int16_t getX(bool sampleNow);
+
+ /**
+ * @param sampleNow if true, queries the device for the sample and returns it. if false, gets the last queried value.
+ * The latter is preferred if this object is set up to sample using interrupts.
+ * @returns a 14-bit value representing the latest data sample for the Y dimension, centered at 0.
+ */
+ int16_t getY(bool sampleNow);
+
+ /**
+ * @param sampleNow if true, queries the device for the sample and returns it. if false, gets the last queried value.
+ * The latter is preferred if this object is set up to sample using interrupts.
+ * @returns a 14-bit value representing the latest data sample for the Z dimension, centered at 0.
+ */
+ int16_t getZ(bool sampleNow);
+
+ /**
+ * @param sampleNow if true, queries the device for the sample and returns it. if false, gets the last queried value.
+ * The latter is preferred if this object is set up to sample using interrupts.
+ * Returns the latest X data reading as a float in Gs
+ */
+ float getFloatX(bool sampleNow);
+
+ /**
+ * @param sampleNow if true, queries the device for the sample and returns it. if false, gets the last queried value.
+ * The latter is preferred if this object is set up to sample using interrupts.
+ * Returns the latest Y data reading as a float in Gs
+ */
+ float getFloatY(bool sampleNow);
+
+ /**
+ * @param sampleNow if true, queries the device for the sample and returns it. if false, gets the last queried value.
+ * The latter is preferred if this object is set up to sample using interrupts.
+ * Returns the latest Z data reading as a float in Gs
+ */
+ float getFloatZ(bool sampleNow);
+
+ virtual void sleep();
+
+ virtual void wake();
+
+ private:
+ /**
+ * Interrupt service routine for fetching accelerometer data from the device.
+ */
+ virtual void __sample_data_ISR();
+
+ ///////////////// CONSTANTS /////////////////////
+
+ //Device register addresses
+ static const uint8_t STATUS = 0x00;
+ static const uint8_t F_STATUS = 0x00;
+ static const uint8_t OUT_X_MSB = 0x01;
+ static const uint8_t OUT_X_LSB = 0x02;
+ static const uint8_t OUT_Y_MSB = 0x03;
+ static const uint8_t OUT_Y_LSB = 0x04;
+ static const uint8_t OUT_Z_MSB = 0x05;
+ static const uint8_t OUT_Z_LSB = 0x06;
+ static const uint8_t F_SETUP = 0x09;
+ static const uint8_t TRIG_CFG = 0x0A;
+ static const uint8_t SYSMOD = 0x0B;
+ static const uint8_t INT_SOURCE = 0x0C;
+ static const uint8_t WHO_AM_I = 0x0D;
+ static const uint8_t XYZ_DATA_CFG = 0x0E;
+ static const uint8_t HP_FILTER_CUTOFF = 0x0F;
+ static const uint8_t PL_STATUS = 0x10;
+ static const uint8_t PL_CFG = 0x11;
+ static const uint8_t PL_COUNT = 0x12;
+ static const uint8_t PL_BF_ZCOMP = 0x13;
+ static const uint8_t P_L_THS_REG = 0x14;
+ static const uint8_t FF_MT_CFG = 0x15;
+ static const uint8_t FF_MT_SRC = 0x16;
+ static const uint8_t FF_MT_THS = 0x17;
+ static const uint8_t FF_MT_COUNT = 0x18;
+ static const uint8_t TRANSIENT_CFG = 0x1D;
+ static const uint8_t TRANSIENT_SRC = 0x1E;
+ static const uint8_t TRANSIENT_THS = 0x1F;
+ static const uint8_t PULSE_CFG = 0x21;
+ static const uint8_t PULSE_SRC = 0x22;
+ static const uint8_t PULSE_THSX = 0x23;
+ static const uint8_t PULSE_THSY = 0x24;
+ static const uint8_t PULSE_THSZ = 0x25;
+ static const uint8_t PULSE_TMLT = 0x26;
+ static const uint8_t PULSE_LTCY = 0x27;
+ static const uint8_t PULSE_WIND = 0x28;
+ static const uint8_t ASLP_COUNT = 0x29;
+ static const uint8_t CTRL_REG1 = 0x2A;
+ static const uint8_t CTRL_REG2 = 0x2B;
+ static const uint8_t CTRL_REG3 = 0x2C;
+ static const uint8_t CTRL_REG4 = 0x2D;
+ static const uint8_t CTRL_REG5 = 0x2E;
+ static const uint8_t OFF_X = 0x2F;
+ static const uint8_t OFF_Y = 0x30;
+ static const uint8_t OFF_Z = 0x31;
+
+ //Register masks
+ static const uint8_t XYZ_DATA_CFG_HPF_OUT_MASK = 0x10; //b0001 0000
+ static const uint8_t XYZ_DATA_CFG_FS_MASK = 0x03; //b0000 0011
+ static const uint8_t CTRL_REG1_ASLP_RATE_MASK = 0xC0; //b1100 0000
+ static const uint8_t CTRL_REG1_DR_MASK = 0x38; //b0011 1000
+ static const uint8_t CTRL_REG1_LNOISE_MASK = 0x04; //b0000 0100
+ static const uint8_t CTRL_REG1_F_READ_MASK = 0x02; //b0000 0010
+ static const uint8_t CTRL_REG1_ACTIVE_MASK = 0x01; //b0000 0001
+ static const uint8_t CTRL_REG2_ST_MASK = 0x80; //b1000 0000
+ static const uint8_t CTRL_REG2_RST_MASK = 0x40; //b0100 0000
+ static const uint8_t CTRL_REG2_SMODS_MASK = 0x18; //b0001 1000
+ static const uint8_t CTRL_REG2_SLPE_MASK = 0x04; //b0000 0100
+ static const uint8_t CTRL_REG2_MODS_MASK = 0x03; //b0000 0011
+ static const uint8_t CTRL_REG3_FIFO_GATE_MASK = 0x80; //b1000 0000
+ static const uint8_t CTRL_REG3_WAKE_TRANS_MASK = 0x40; //b0100 0000
+ static const uint8_t CTRL_REG3_WAKE_LNDPRT_MASK = 0x20; //b0010 0000
+ static const uint8_t CTRL_REG3_WAKE_PULSE_MASK = 0x10; //b0001 0000
+ static const uint8_t CTRL_REG3_WAKE_FF_MT_MASK = 0x08; //b0000 1000
+ static const uint8_t CTRL_REG3_IPOL_MASK = 0x02; //b0000 0010
+ static const uint8_t CTRL_REG3_PP_OD_MASK = 0x01; //b0000 0001
+ static const uint8_t CTRL_REG4_INT_EN_ASLP_MASK = 0x80; //b1000 0000
+ static const uint8_t CTRL_REG4_INT_EN_FIFO_MASK = 0x40; //b0100 0000
+ static const uint8_t CTRL_REG4_INT_EN_TRANS_MASK = 0x20; //b0010 0000
+ static const uint8_t CTRL_REG4_INT_EN_LNDPR_MASK = 0x10; //b0001 0000
+ static const uint8_t CTRL_REG4_INT_EN_PULSE_MASK = 0x08; //b0000 1000
+ static const uint8_t CTRL_REG4_INT_EN_FF_MT_MASK = 0x04; //b0000 0100
+ static const uint8_t CTRL_REG4_INT_EN_DRDY_MASK = 0x01; //b0000 0001
+ static const uint8_t CTRL_REG5_INT_CFG_ASLP_MASK = 0x80; //b1000 0000
+ static const uint8_t CTRL_REG5_INT_CFG_FIFO_MASK = 0x40; //b0100 0000
+ static const uint8_t CTRL_REG5_INT_CFG_TRANS_MASK = 0x20; //b0010 0000
+ static const uint8_t CTRL_REG5_INT_CFG_LNDPRT_MASK = 0x10; //b0001 0000
+ static const uint8_t CTRL_REG5_INT_CFG_PULSE_MASK = 0x08; //b0000 1000
+ static const uint8_t CTRL_REG5_INT_CFG_FF_MT_MASK = 0x04; //b0000 0100
+ static const uint8_t CTRL_REG5_INT_CFG_DRDY_MASK = 0x01; //b0000 0001
+
+ //Mapping of sensor values
+ static const float G2_DIV = 0.00024414; // in Gs/level, 1/4096
+ static const float G4_DIV = 0.00048828; // in Gs/level, 1/2048
+ static const float G8_DIV = 0.00097656; // in Gs/level, 1/1024
+
+
+ ////////////// VARIABLES /////////////////
+
+ //MMA8451Q state ("cached" from the values actually on the device)
+ volatile int16_t __x;
+ volatile int16_t __y;
+ volatile int16_t __z;
+
+ bool __active;
+ bool __14b_data_enabled;
+ smpl_rate_t __output_data_rate;
+ scale_t __scale;
+ float __div; //current sensor mapping
+};
+
+#endif
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