Revision 1:204db61f9c8f, committed 2014-08-19

Comitter:

B50132

Date:

Tue Aug 19 15:05:55 2014 +0000

Parent:

0:7c9ab58f6af3

Commit message:

modified contents with another library doing the same thing.

Changed in this revision

--- a/MMA8451Q.cpp	Wed Jun 04 19:16:47 2014 +0000
+++ b/MMA8451Q.cpp	Tue Aug 19 15:05:55 2014 +0000
@@ -1,5 +1,4 @@
 /* Copyright (c) 2010-2011 mbed.org, MIT License
-* Copyright (c) 2014 Antonio Quevedo, UNICAMP
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
 * and associated documentation files (the "Software"), to deal in the Software without
@@ -19,57 +18,64 @@
 
 #include "MMA8451Q.h"
 
-#define ACCEL_I2C_ADDRESS 0x1D<<1
-#define REG_STATUS        0x00
-#define REG_XYZ_DATA_CFG  0x0E
 #define REG_WHO_AM_I      0x0D
-#define REG_CTRL_REG1     0x2A
-#define REG_CTRL_REG2     0x2B
-#define REG_CTRL_REG3     0x2C
-#define REG_CTRL_REG4     0x2D
-#define REG_CTRL_REG5     0x2E
+#define REG_CTRL_REG_1    0x2A
 #define REG_OUT_X_MSB     0x01
 #define REG_OUT_Y_MSB     0x03
 #define REG_OUT_Z_MSB     0x05
 
-MMA8451Q::MMA8451Q(PinName sda, PinName scl) : m_i2c(sda, scl) {
-    uint8_t data[2] = {REG_CTRL_REG1, 0x00}; // Puts acc in standby for configuring
-    writeRegs(data, 2);
-    data[0] = REG_XYZ_DATA_CFG; // Writing 00 turns off high-pass filter and sets full scale range to 2g
-    // data[1] = 0x01; for 4g
-    // data[1] = 0x02; for 8g
-    writeRegs(data, 2);
-    data[0] = REG_CTRL_REG2;
-    data[1] = 0x00; // Disable self-test, software reset and auto-sleep; operates in normal mode
-    writeRegs(data, 2);
-    data[0] = REG_CTRL_REG3; // Interrupt polarity low, push-pull output
-    writeRegs(data, 2);
-    data[0] = REG_CTRL_REG4;
-    data[1] = 0x01; // Enables interrupt for data Ready
-    writeRegs(data, 2);
-    data[0] = REG_CTRL_REG5;
-    writeRegs(data, 2); // Routes Data Ready interrupt to INT1
-    data[0] = REG_CTRL_REG1; 
-    data[1] = 0x09; // Data rate is 800Hz
+#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};
     writeRegs(data, 2);
 }
 
 MMA8451Q::~MMA8451Q() { }
 
-void MMA8451Q::getAccAllAxis(int16_t * res) {
-    uint8_t temp[6];
-    readRegs(REG_OUT_X_MSB, temp, 6);
-    res[0] = (temp[0] * 256) + temp[1];
-    res[1] = (temp[2] * 256) + temp[3];
-    res[2] = (temp[4] * 256) + temp[5];
+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() {
+    return (float(getAccAxis(REG_OUT_X_MSB))/4096.0);
+}
+
+float MMA8451Q::getAccY() {
+    return (float(getAccAxis(REG_OUT_Y_MSB))/4096.0);
+}
+
+float MMA8451Q::getAccZ() {
+    return (float(getAccAxis(REG_OUT_Z_MSB))/4096.0);
+}
+
+void MMA8451Q::getAccAllAxis(float * res) {
+    res[0] = getAccX();
+    res[1] = getAccY();
+    res[2] = getAccZ();
+}
+
+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);
+    if (acc > UINT14_MAX/2)
+        acc -= UINT14_MAX;
+
+    return acc;
 }
 
 void MMA8451Q::readRegs(int addr, uint8_t * data, int len) {
     char t[1] = {addr};
-    m_i2c.write(ACCEL_I2C_ADDRESS, t, 1, true);
-    m_i2c.read(ACCEL_I2C_ADDRESS, (char *)data, len);
+    m_i2c.write(m_addr, t, 1, true);
+    m_i2c.read(m_addr, (char *)data, len);
 }
 
 void MMA8451Q::writeRegs(uint8_t * data, int len) {
-    m_i2c.write(ACCEL_I2C_ADDRESS, (char *)data, len);
-}
\ No newline at end of file
+    m_i2c.write(m_addr, (char *)data, len);
+}

--- a/MMA8451Q.h	Wed Jun 04 19:16:47 2014 +0000
+++ b/MMA8451Q.h	Tue Aug 19 15:05:55 2014 +0000
@@ -1,5 +1,4 @@
 /* Copyright (c) 2010-2011 mbed.org, MIT License
-* Copyright (c) 2014 Antonio Quevedo, UNICAMP
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
 * and associated documentation files (the "Software"), to deal in the Software without
@@ -23,26 +22,26 @@
 #include "mbed.h"
 
 /**
-* MMA8451Q accelerometer example, 8-bit samples
+* MMA8451Q accelerometer example
 *
 * @code
 * #include "mbed.h"
 * #include "MMA8451Q.h"
 * 
+* #define MMA8451_I2C_ADDRESS (0x1d<<1)
+* 
 * int main(void) {
 * 
-* MMA8451Q acc(PTE25, PTE24);
+* MMA8451Q acc(P_E25, P_E24, MMA8451_I2C_ADDRESS);
 * PwmOut rled(LED_RED);
 * PwmOut gled(LED_GREEN);
 * PwmOut bled(LED_BLUE);
-* uint8_t data[3];
-*
-*     while (true) {
-          acc.getAccAllAxis(data);       
-*         rled = 1.0 - abs(data[0]/128);
-*         gled = 1.0 - abs(data[0]/128);
-*         bled = 1.0 - abs(data[0]/128);
-*         wait(0.4);
+* 
+*     while (true) {       
+*         rled = 1.0 - abs(acc.getAccX());
+*         gled = 1.0 - abs(acc.getAccY());
+*         bled = 1.0 - abs(acc.getAccZ());
+*         wait(0.1);
 *     }
 * }
 * @endcode
@@ -55,8 +54,9 @@
   *
   * @param sda SDA pin
   * @param sdl SCL pin
+  * @param addr addr of the I2C peripheral
   */
-  MMA8451Q(PinName sda, PinName scl);
+  MMA8451Q(PinName sda, PinName scl, int addr);
 
   /**
   * MMA8451Q destructor
@@ -64,17 +64,47 @@
   ~MMA8451Q();
 
   /**
-   * Get XYZ axis acceleration, 8-bits
+   * 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 Y axis acceleration
+   *
+   * @returns Y axis acceleration
+   */
+  float getAccY();
+
+  /**
+   * 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(int16_t * res);
+  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);
 
 };
 
-#endif
\ No newline at end of file
+#endif