Revision 0:6149091f755d, committed 2012-10-11

Comitter:

emilmont

Date:

Thu Oct 11 10:54:16 2012 +0000

Child:

1:d2630136d51e

Commit message:

Package samux acceleromiter library;

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MMA8451Q.cpp	Thu Oct 11 10:54:16 2012 +0000
@@ -0,0 +1,63 @@
+#include "MMA8451Q.h"
+
+#define REG_WHO_AM_I       0x0D
+#define REG_CTRL_REG_1     0x2A
+#define REG_OUT_X_MSB     0x01
+#define REG_OUT_Y_MSB     0x03
+#define REG_OUT_Z_MSB     0x05
+
+#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};
+    write_regs(data, 2);
+}
+
+MMA8451Q::~MMA8451Q() { }
+
+uint8_t MMA8451Q::getWhoAmI() {
+    uint8_t who_am_i = 0;
+    read_regs(REG_WHO_AM_I, &who_am_i, 1);
+    return who_am_i;
+}
+
+int16_t MMA8451Q::getAccX() {
+    return getAccAxis(REG_OUT_X_MSB);
+}
+
+int16_t MMA8451Q::getAccY() {
+    return getAccAxis(REG_OUT_Y_MSB);
+}
+
+int16_t MMA8451Q::getAccZ() {
+    return getAccAxis(REG_OUT_Z_MSB);
+}
+
+void MMA8451Q::getAccAllAxis(int16_t * res) {
+    res[0] = getAccX();
+    res[1] = getAccY();
+    res[2] = getAccZ();
+}
+
+int16_t MMA8451Q::getAccAxis(uint8_t addr) {
+    int16_t acc;
+    uint8_t res[2];
+    read_regs(addr, res, 2);
+
+    acc = (res[0] << 6) | (res[1] >> 2);
+    if (acc > UINT14_MAX/2)
+        acc -= UINT14_MAX;
+
+    return acc;
+}
+
+void MMA8451Q::read_regs(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::write_regs(uint8_t * data, int len) {
+    m_i2c.write(m_addr, (char *)data, len);
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MMA8451Q.h	Thu Oct 11 10:54:16 2012 +0000
@@ -0,0 +1,70 @@
+#ifndef MMA8451Q_H
+#define MMA8451Q_H
+
+#include "mbed.h"
+
+//!Library for the MMA8451Q motion sensor.
+class MMA8451Q
+{
+public:
+  //!Creates an instance of the class.
+  /*
+  * Connect module at I2C address addr using I2C port pins sda and scl.
+  * MMA8451Q
+  * \param sda SDA pin
+  * \param sdl SCL pin
+  * \param addr addr of the I2C peripheral
+  */
+  MMA8451Q(PinName sda, PinName scl, int addr);
+
+  /*
+  * Destroys instance.
+  */
+  ~MMA8451Q();
+
+  /*
+   * 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
+   */
+  int16_t getAccX();
+
+  /*
+   * Get Y axis acceleration
+   *
+   * \returns Y axis acceleration
+   */
+  int16_t getAccY();
+
+  /*
+   * Get Z axis acceleration
+   *
+   * \returns Z axis acceleration
+   */
+  int16_t getAccZ();
+
+  /*
+   * Get XYZ axis acceleration
+   *
+   * \param res array where acceleration data will be stored
+   */
+  void    getAccAllAxis(int16_t * res);
+
+  I2C m_i2c;
+
+private:
+  int m_addr;
+  void read_regs(int addr, uint8_t * data, int len);
+  void write_regs(uint8_t * data, int len);
+  int16_t getAccAxis(uint8_t addr);
+
+};
+
+#endif