Revision 5:d813fe6c0c70, committed 2013-03-14

Comitter:

SomeRandomBloke

Date:

Thu Mar 14 21:57:04 2013 +0000

Parent:

4:c4d879a39775

Child:

6:e8bacad228f6

Commit message:

Work on an updated MMA8451Q Accelerometor library

Changed in this revision

--- a/MMA8451Q.cpp	Fri Oct 12 11:35:07 2012 +0000
+++ b/MMA8451Q.cpp	Thu Mar 14 21:57:04 2013 +0000
@@ -18,6 +18,38 @@
 
 #include "MMA8451Q.h"
 
+#define MMA_845XQ_CTRL_REG1 0x2A
+#define MMA_845XQ_CTRL_REG1_VALUE_ACTIVE 0x01
+#define MMA_845XQ_CTRL_REG1_VALUE_F_READ 0x02
+
+#define MMA_845XQ_CTRL_REG2 0x2B
+#define MMA_845XQ_CTRL_REG2_RESET 0x40
+
+#define MMA_845XQ_PL_STATUS 0x10
+#define MMA_845XQ_PL_CFG 0x11
+#define MMA_845XQ_PL_EN 0x40
+
+#define MMA_845XQ_XYZ_DATA_CFG 0x0E
+#define MMA_845XQ_2G_MODE 0x00 //Set Sensitivity to 2g
+#define MMA_845XQ_4G_MODE 0x01 //Set Sensitivity to 4g
+#define MMA_845XQ_8G_MODE 0x02 //Set Sensitivity to 8g
+#define MMA_845XQ_HPF_OUT 0x10 //Set High pas filter out
+
+
+#define MMA_845XQ_FF_MT_CFG 0x15
+#define MMA_845XQ_FF_MT_CFG_ELE 0x80
+#define MMA_845XQ_FF_MT_CFG_OAE 0x40
+
+#define MMA_845XQ_FF_MT_SRC 0x16
+#define MMA_845XQ_FF_MT_SRC_EA 0x80
+
+#define MMA_845XQ_PULSE_CFG 0x21
+#define MMA_845XQ_PULSE_CFG_ELE 0x80
+
+#define MMA_845XQ_PULSE_SRC 0x22
+#define MMA_845XQ_PULSE_SRC_EA 0x80
+
+// Original
 #define REG_WHO_AM_I      0x0D
 #define REG_CTRL_REG_1    0x2A
 #define REG_OUT_X_MSB     0x01
@@ -26,56 +58,115 @@
 
 #define UINT14_MAX        16383
 
-MMA8451Q::MMA8451Q(PinName sda, PinName scl, int addr) : m_i2c(sda, scl), m_addr(addr) {
-    // activate the peripheral
-    uint8_t data[2] = {REG_CTRL_REG_1, 0x01};
+MMA8451Q::MMA8451Q(PinName sda, PinName scl, int addr, bool highres, uint8_t scale) : m_i2c(sda, scl), m_addr(addr)
+{
+    _highres = highres;
+    _scale = scale;
+    _step_factor = (_highres ? 0.0039 : 0.0156); // Base value at 2g setting
+    if( _scale == 4 )
+        _step_factor *= 2;
+    else if (_scale == 8)
+        _step_factor *= 4;
+
+    // Set parameters
+    uint8_t data[2] = {REG_CTRL_REG_1, 0x04};
     writeRegs(data, 2);
+
+    // Activate
+    data[1] = 0x05;
+    writeRegs(data, 2);
+
+  data[0] = MMA_845XQ_XYZ_DATA_CFG;
+  if (_scale == 4 || _scale == 8)
+    data[1] = (_scale == 4) ? MMA_845XQ_4G_MODE : MMA_845XQ_8G_MODE;
+  else // Default to 2g mode
+    data[1] = (uint8_t)MMA_845XQ_2G_MODE;
+    
+//  data[1] |= MMA_845XQ_HPF_OUT;
+  writeRegs(data, 2);
 }
 
 MMA8451Q::~MMA8451Q() { }
 
-uint8_t MMA8451Q::getWhoAmI() {
+uint8_t MMA8451Q::getWhoAmI()
+{
     uint8_t who_am_i = 0;
     readRegs(REG_WHO_AM_I, &who_am_i, 1);
     return who_am_i;
 }
 
-float MMA8451Q::getAccX() {
+float MMA8451Q::getAccX()
+{
+//    return (getAccAxis(REG_OUT_X_MSB));
     return (float(getAccAxis(REG_OUT_X_MSB))/4096.0);
 }
 
-float MMA8451Q::getAccY() {
+float MMA8451Q::getAccY()
+{
+//    return (getAccAxis(REG_OUT_Y_MSB));
     return (float(getAccAxis(REG_OUT_Y_MSB))/4096.0);
 }
 
-float MMA8451Q::getAccZ() {
+float MMA8451Q::getAccZ()
+{
+//    return (getAccAxis(REG_OUT_Z_MSB));
     return (float(getAccAxis(REG_OUT_Z_MSB))/4096.0);
 }
 
-void MMA8451Q::getAccAllAxis(float * res) {
+void MMA8451Q::getAccAllAxis(float * res)
+{
     res[0] = getAccX();
     res[1] = getAccY();
     res[2] = getAccZ();
 }
 
-int16_t MMA8451Q::getAccAxis(uint8_t addr) {
+float MMA8451Q::getAccAxisF(uint8_t addr)
+{
     int16_t acc;
+    float facc;
     uint8_t res[2];
     readRegs(addr, res, 2);
 
     acc = (res[0] << 6) | (res[1] >> 2);
     if (acc > UINT14_MAX/2)
         acc -= UINT14_MAX;
+return (acc * 4096.0);
+/*    
+    if(_highres)
+    {
+      acc = (int16_t)(res[0] << 8) + res[1];
+      facc = (acc / 64) * _step_factor;
+    }
+    else
+    {
+      facc = (float)((int16_t)(res[0] * _step_factor) * 1.0);
+    }
+    return acc;
+*/
+}
 
+int16_t MMA8451Q::getAccAxis(uint8_t addr)
+{
+    int16_t acc;
+    uint8_t res[2];
+    readRegs(addr, res, 2);
+
+//    acc = (res[0] << 6) | (res[1] >> 2);
+    acc = (res[0] << 8) | (res[1]);
+    acc = acc >> 2;
+//    if (acc > UINT14_MAX/2)
+//        acc -= UINT14_MAX;
     return acc;
 }
 
-void MMA8451Q::readRegs(int addr, uint8_t * data, int len) {
+void MMA8451Q::readRegs(int addr, uint8_t * data, int len)
+{
     char t[1] = {addr};
     m_i2c.write(m_addr, t, 1, true);
     m_i2c.read(m_addr, (char *)data, len);
 }
 
-void MMA8451Q::writeRegs(uint8_t * data, int len) {
+void MMA8451Q::writeRegs(uint8_t * data, int len)
+{
     m_i2c.write(m_addr, (char *)data, len);
 }

--- a/MMA8451Q.h	Fri Oct 12 11:35:07 2012 +0000
+++ b/MMA8451Q.h	Thu Mar 14 21:57:04 2013 +0000
@@ -27,17 +27,17 @@
 * @code
 * #include "mbed.h"
 * #include "MMA8451Q.h"
-* 
+*
 * #define MMA8451_I2C_ADDRESS (0x1d<<1)
-* 
+*
 * int main(void) {
-* 
+*
 * MMA8451Q acc(P_E25, P_E24, MMA8451_I2C_ADDRESS);
 * PwmOut rled(LED_RED);
 * PwmOut gled(LED_GREEN);
 * PwmOut bled(LED_BLUE);
-* 
-*     while (true) {       
+*
+*     while (true) {
 *         rled = 1.0 - abs(acc.getAccX());
 *         gled = 1.0 - abs(acc.getAccY());
 *         bled = 1.0 - abs(acc.getAccZ());
@@ -49,61 +49,65 @@
 class MMA8451Q
 {
 public:
-  /**
-  * MMA8451Q constructor
-  *
-  * @param sda SDA pin
-  * @param sdl SCL pin
-  * @param addr addr of the I2C peripheral
-  */
-  MMA8451Q(PinName sda, PinName scl, int addr);
+    /**
+    * MMA8451Q constructor
+    *
+    * @param sda SDA pin
+    * @param sdl SCL pin
+    * @param addr addr of the I2C peripheral
+    */
+    MMA8451Q(PinName sda, PinName scl, int addr, bool highres, uint8_t scale);
 
-  /**
-  * MMA8451Q destructor
-  */
-  ~MMA8451Q();
+    /**
+    * MMA8451Q destructor
+    */
+    ~MMA8451Q();
 
-  /**
-   * Get the value of the WHO_AM_I register
-   *
-   * @returns WHO_AM_I value
-   */
-  uint8_t getWhoAmI();
+    /**
+     * Get the value of the WHO_AM_I register
+     *
+     * @returns WHO_AM_I value
+     */
+    uint8_t getWhoAmI();
 
-  /**
-   * Get X axis acceleration
-   *
-   * @returns X axis acceleration
-   */
-  float getAccX();
+    /**
+     * Get X axis acceleration
+     *
+     * @returns X axis acceleration
+     */
+    float getAccX();
 
-  /**
-   * Get Y axis acceleration
-   *
-   * @returns Y axis acceleration
-   */
-  float getAccY();
+    /**
+     * Get Y axis acceleration
+     *
+     * @returns Y axis acceleration
+     */
+    float getAccY();
 
-  /**
-   * Get Z axis acceleration
-   *
-   * @returns Z axis acceleration
-   */
-  float getAccZ();
+    /**
+     * Get Z axis acceleration
+     *
+     * @returns Z axis acceleration
+     */
+    float getAccZ();
 
-  /**
-   * Get XYZ axis acceleration
-   *
-   * @param res array where acceleration data will be stored
-   */
-  void getAccAllAxis(float * res);
+    /**
+     * Get XYZ axis acceleration
+     *
+     * @param res array where acceleration data will be stored
+     */
+    void getAccAllAxis(float * res);
 
 private:
-  I2C m_i2c;
-  int m_addr;
-  void readRegs(int addr, uint8_t * data, int len);
-  void writeRegs(uint8_t * data, int len);
-  int16_t getAccAxis(uint8_t addr);
+    I2C m_i2c;
+    int m_addr;
+    void readRegs(int addr, uint8_t * data, int len);
+    void writeRegs(uint8_t * data, int len);
+    int16_t getAccAxis(uint8_t addr);
+    float getAccAxisF(uint8_t addr);
+    uint8_t _scale;
+    float _step_factor;
+    bool _highres;
 
 };