Revision 3:3514575d4f86, committed 2014-07-23

Comitter:

mjr

Date:

Wed Jul 23 17:53:28 2014 +0000

Parent:

2:c174f9ee414a

Child:

4:02c7cd7b2183

Commit message:

Conversion to interrupt-based sampling of the accelerometer working

Changed in this revision

--- a/MMA8451Q/MMA8451Q.cpp	Tue Jul 22 04:33:47 2014 +0000
+++ b/MMA8451Q/MMA8451Q.cpp	Wed Jul 23 17:53:28 2014 +0000
@@ -57,12 +57,29 @@
 #define DR_6_HZ           0x30
 #define DR_1_HZ           0x38
 
+#define CTRL_REG3_IPOL_MASK  0x02
+#define CTRL_REG3_PPOD_MASK  0x01
+
+#define INT_EN_DRDY       0x01
+#define INT_CFG_DRDY      0x01
+
 
 MMA8451Q::MMA8451Q(PinName sda, PinName scl, int addr) : m_i2c(sda, scl), m_addr(addr) 
 {
     // go to standby mode
     standby();
     
+#if 0
+    // reset all registers to power-on reset values
+    uint8_t d0[2] = { REG_CTRL_REG_2, 0x40 };
+    writeRegs(d0,2 );
+    
+    // wait for the reset bit to clear
+    do {
+        readRegs(REG_CTRL_REG_2, d0, 1);
+    } while ((d0[0] & 0x40) != 0);
+#endif
+    
     // read the curent config register
     uint8_t d1[1];
     readRegs(XYZ_DATA_CFG_REG, d1, 1);
@@ -79,10 +96,10 @@
     uint8_t d4[2] = {REG_CTRL_REG_2, (d3[0] & ~MODS_MASK) | MODS1_MASK};
     writeRegs(d4, 2);
     
-    // set 100 Hz mode
+    // set 800 Hz mode
     uint8_t d5[1];
     readRegs(REG_CTRL_REG_1, d5, 1);
-    uint8_t d6[2] = {REG_CTRL_REG_1, (d5[0] & ~DR_MASK) | DR_100_HZ};
+    uint8_t d6[2] = {REG_CTRL_REG_1, (d5[0] & ~DR_MASK) | DR_800_HZ};
     writeRegs(d6, 2);
     
     // enter active mode
@@ -91,6 +108,37 @@
 
 MMA8451Q::~MMA8451Q() { }
 
+void MMA8451Q::setInterruptMode(int pin)
+{
+    // go to standby mode
+    standby();
+
+    // set IRQ push/pull and active high
+    uint8_t d1[1];
+    readRegs(REG_CTRL_REG_3, d1, 1);
+    uint8_t d2[2] = {
+        REG_CTRL_REG_3, 
+        (d1[0] & ~CTRL_REG3_PPOD_MASK) | CTRL_REG3_IPOL_MASK
+    };
+    writeRegs(d2, 2);
+    
+    // set pin 2 or pin 1
+    readRegs(REG_CTRL_REG_5, d1, 1);
+    uint8_t d3[2] = { 
+        REG_CTRL_REG_5, 
+        (d1[0] & ~INT_CFG_DRDY) | (pin == 1 ? INT_CFG_DRDY : 0)
+    };
+    writeRegs(d3, 2);
+    
+    // enable data ready interrupt
+    readRegs(REG_CTRL_REG_4, d1, 1);
+    uint8_t d4[2] = { REG_CTRL_REG_4, d1[0] | INT_EN_DRDY };
+    writeRegs(d4, 2);
+    
+    // enter active mode
+    active();
+}
+
 void MMA8451Q::standby()
 {
     // read the current control register
@@ -138,6 +186,25 @@
     y = int16_t(acc)/(4*4096.0);
 }
 
+void MMA8451Q::getAccXYZ(float &x, float &y, float &z)
+{
+    // read the X, Y, and Z output registers
+    uint8_t res[6];
+    readRegs(REG_OUT_X_MSB, res, 6);
+    
+    // translate the x value
+    uint16_t acc = (res[0] << 8) | (res[1]);
+    x = int16_t(acc)/(4*4096.0);
+    
+    // translate the y value
+    acc = (res[2] << 8) | (res[3]);
+    y = int16_t(acc)/(4*4096.0);
+    
+    // translate the z value
+    acc = (res[4] << 8) | (res[5]);
+    z = int16_t(acc)/(4*4096.0);
+}
+
 float MMA8451Q::getAccY() {
     return (float(getAccAxis(REG_OUT_Y_MSB))/4096.0);
 }

--- a/MMA8451Q/MMA8451Q.h	Tue Jul 22 04:33:47 2014 +0000
+++ b/MMA8451Q/MMA8451Q.h	Wed Jul 23 17:53:28 2014 +0000
@@ -98,6 +98,13 @@
    *  Read an X,Y pair
    */
   void getAccXY(float &x, float &y);
+  
+  /**
+   *  Read X,Y,Z.  This is the most efficient way to fetch
+   *  all of the axes at once, since it fetches all three
+   *  in a single I2C transaction.
+   */
+  void getAccXYZ(float &x, float &y, float &z);
 
   /**
    * Get Z axis acceleration
@@ -112,6 +119,13 @@
    * @param res array where acceleration data will be stored
    */
   void getAccAllAxis(float * res);
+  
+  /**
+   * Set interrupt mode.  'pin' is 1 for INT1_ACCEL (PTA14) and 2 for INT2_ACCEL (PTA15).
+   * The caller is responsible for setting up an interrupt handler on the corresponding
+   * PTAxx pin.
+   */
+  void setInterruptMode(int pin);
 
 private:
   I2C m_i2c;

--- a/USBJoystick.cpp	Tue Jul 22 04:33:47 2014 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,143 +0,0 @@
-/* Copyright (c) 2010-2011 mbed.org, MIT License
-* Modified Mouse code for Joystick - WH 2012
-*
-* 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
-* restriction, including without limitation the rights to use, copy, modify, merge, publish,
-* distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the
-* Software is furnished to do so, subject to the following conditions:
-*
-* The above copyright notice and this permission notice shall be included in all copies or
-* substantial portions of the Software.
-*
-* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
-* BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
-* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
-* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-*/
- 
-#include "stdint.h"
-#include "USBJoystick.h"
- 
-bool USBJoystick::update(int16_t x, int16_t y, int16_t z, uint16_t buttons) 
-{
-   _x = x;
-   _y = y;
-   _z = z;
-   _buttons = buttons;     
- 
-   // send the report
-   return update();
-}
- 
-bool USBJoystick::update() {
-   HID_REPORT report;
- 
-   // Fill the report according to the Joystick Descriptor
-   report.data[0] = _buttons & 0xff;
-   report.data[1] = (_buttons >> 8) & 0xff;
-   report.data[2] = _x & 0xff;            
-   report.data[3] = _y & 0xff;            
-   report.data[4] = _z & 0xff;
-   report.length = 5; 
- 
-   return sendNB(&report);
-}
- 
-bool USBJoystick::move(int16_t x, int16_t y) {
-     _x = x;
-     _y = y;
-     return update();
-}
-
-bool USBJoystick::setZ(int16_t z) {
-    _z = z;
-    return update();
-}
- 
-bool USBJoystick::buttons(uint16_t buttons) {
-     _buttons = buttons;
-     return update();
-}
- 
- 
-void USBJoystick::_init() {
- 
-   _x = 0;                       
-   _y = 0;     
-   _z = 0;
-   _buttons = 0x0000;
-}
- 
- 
-uint8_t * USBJoystick::reportDesc() 
-{    
-    static uint8_t reportDescriptor[] = 
-    {         
-         USAGE_PAGE(1), 0x01,            // Generic desktop
-         USAGE(1), 0x04,                 // Joystick
-
-         COLLECTION(1), 0x01,            // Application
-      //     COLLECTION(1), 0x00,          // Physical
-           
-             USAGE_PAGE(1), 0x09,        // Buttons
-             USAGE_MINIMUM(1), 0x01,     // { buttons }
-             USAGE_MAXIMUM(1), 0x10,     // {  1-16   }
-             LOGICAL_MINIMUM(1), 0x00,   // 1-bit buttons - 0...
-             LOGICAL_MAXIMUM(1), 0x01,   // ...to 1
-             REPORT_SIZE(1), 0x01,       // 1 bit per report
-             REPORT_COUNT(1), 0x10,      // 16 reports
-             UNIT_EXPONENT(1), 0x00,     // Unit_Exponent (0)
-             UNIT(1), 0x00,              // Unit (None)                                           
-             INPUT(1), 0x02,             // Data, Variable, Absolute
-           
-             USAGE_PAGE(1), 0x01,        // Generic desktop
-             USAGE(1), 0x30,             // X
-             USAGE(1), 0x31,             // Y
-             USAGE(1), 0x32,             // Z
-             LOGICAL_MINIMUM(1), 0x81,   // each value ranges -127...
-             LOGICAL_MAXIMUM(1), 0x7f,   // ...to 127
-             REPORT_SIZE(1), 0x08,       // 8 bits per report
-             REPORT_COUNT(1), 0x03,      // 2 reports
-             INPUT(1), 0x02,             // Data, Variable, Absolute
-
-             REPORT_COUNT(1), 0x08,      // input report count (LEDWiz messages)
-             0x09, 0x01,                 // usage
-             0x91, 0x01,                 // Output (array)
-
-     //      END_COLLECTION(0),
-         END_COLLECTION(0)
-      };
- 
-      reportLength = sizeof(reportDescriptor);
-      return reportDescriptor;
-}
- 
- uint8_t * USBJoystick::stringImanufacturerDesc() {
-    static uint8_t stringImanufacturerDescriptor[] = {
-        0x10,                                            /*bLength*/
-        STRING_DESCRIPTOR,                               /*bDescriptorType 0x03*/
-        'm',0,'j',0,'r',0,'c',0,'o',0,'r',0,'p',0        /*bString iManufacturer - mjrcorp*/
-    };
-    return stringImanufacturerDescriptor;
-}
-
-uint8_t * USBJoystick::stringIserialDesc() {
-    static uint8_t stringIserialDescriptor[] = {
-        0x16,                                                           /*bLength*/
-        STRING_DESCRIPTOR,                                              /*bDescriptorType 0x03*/
-        '0',0,'1',0,'2',0,'3',0,'4',0,'5',0,'6',0,'7',0,'8',0,'9',0,    /*bString iSerial - 0123456789*/
-    };
-    return stringIserialDescriptor;
-}
-
-uint8_t * USBJoystick::stringIproductDesc() {
-    static uint8_t stringIproductDescriptor[] = {
-        0x1E,                                                       /*bLength*/
-        STRING_DESCRIPTOR,                                          /*bDescriptorType 0x03*/
-        'P',0,'i',0,'n',0,'M',0,'a',0,'s',0,'t',0,'e',0,'r',0,
-        ' ',0,'2',0,'0',0,'0',0,'0',0                               /*String iProduct - PinMaster 2000*/
-    };
-    return stringIproductDescriptor;
-}

--- a/USBJoystick.h	Tue Jul 22 04:33:47 2014 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,163 +0,0 @@
-/* USBJoystick.h */
-/* USB device example: Joystick*/
-/* Copyright (c) 2011 ARM Limited. All rights reserved. */
-/* Modified Mouse code for Joystick - WH 2012 */
- 
-#ifndef USBJOYSTICK_H
-#define USBJOYSTICK_H
- 
-#include "USBHID.h"
- 
-#define REPORT_ID_JOYSTICK  4
- 
-/* Common usage */
-enum JOY_BUTTON {
-     JOY_B0 = 0x0001,
-     JOY_B1 = 0x0002,
-     JOY_B2 = 0x0004,
-     JOY_B3 = 0x0008,
-     JOY_B4 = 0x0010,
-     JOY_B5 = 0x0020,
-     JOY_B6 = 0x0040,
-     JOY_B7 = 0x0080,
-     JOY_B8 = 0x0100,
-     JOY_B9 = 0x0200,
-     JOY_B10 = 0x0400,
-     JOY_B11 = 0x0800,
-     JOY_B12 = 0x1000,
-     JOY_B13 = 0x2000,
-     JOY_B14 = 0x4000,
-     JOY_B15 = 0x8000
-};
- 
-/* X, Y and T limits */
-/* These values do not directly map to screen pixels */
-/* Zero may be interpreted as meaning 'no movement' */
-#define JX_MIN_ABS    (-127)     /*!< The maximum value that we can move to the left on the x-axis */
-#define JY_MIN_ABS    (-127)     /*!< The maximum value that we can move up on the y-axis */
-#define JZ_MIN_ABS    (-127)     /*!< The minimum value for the Z axis */
-#define JX_MAX_ABS    (127)      /*!< The maximum value that we can move to the right on the x-axis */
-#define JY_MAX_ABS    (127)      /*!< The maximum value that we can move down on the y-axis */
-#define JZ_MAX_ABS    (127)      /*!< The maximum value for the Z axis */
- 
-/**
- *
- * USBJoystick example
- * @code
- * #include "mbed.h"
- * #include "USBJoystick.h"
- *
- * USBJoystick joystick;
- *
- * int main(void)
- * {
- *   while (1)
- *   {
- *      joystick.move(20, 0);
- *      wait(0.5);
- *   }
- * }
- *
- * @endcode
- *
- *
- * @code
- * #include "mbed.h"
- * #include "USBJoystick.h"
- * #include <math.h>
- *
- * USBJoystick joystick;
- *
- * int main(void)
- * {   
- *   while (1) {
- *       // Basic Joystick
- *       joystick.update(tx, y, z, buttonBits);
- *       wait(0.001);
- *   }
- * }
- * @endcode
- */
- 
- 
-class USBJoystick: public USBHID {
-   public:
- 
-        /**
-         *   Constructor
-         *
-         * @param vendor_id Your vendor_id (default: 0x1234)
-         * @param product_id Your product_id (default: 0x0002)
-         * @param product_release Your product_release (default: 0x0001)
-         */
-         USBJoystick(uint16_t vendor_id = 0x1234, uint16_t product_id = 0x0100, uint16_t product_release = 0x0001): 
-             USBHID(8, 8, vendor_id, product_id, product_release, false)
-             { 
-                 _init();
-                 connect();
-             };
-         
-         /**
-         * Write a state of the mouse
-         *
-         * @param x x-axis position
-         * @param y y-axis position
-         * @param z z-axis position
-         * @param buttons buttons state, as a bit mask (combination with '|' of JOY_Bn values)
-         * @returns true if there is no error, false otherwise
-         */
-         bool update(int16_t x, int16_t y, int16_t z, uint16_t buttons);
- 
-         /**
-         * Write a state of the mouse
-         *
-         * @returns true if there is no error, false otherwise
-         */
-         bool update();
- 
-         /**
-         * Move the cursor to (x, y)
-         *
-         * @param x x-axis position
-         * @param y y-axis position
-         * @returns true if there is no error, false otherwise
-         */
-         bool move(int16_t x, int16_t y);
-         
-         /**
-         * Set the z position
-         *
-         * @param z z-axis osition
-         */
-         bool setZ(int16_t z);
-         
-         /**
-         * Press one or several buttons
-         *
-         * @param buttons button state, as a bitwise combination of JOY_Bn values
-         * @returns true if there is no error, false otherwise
-         */
-         bool buttons(uint16_t buttons);
-         
-         /*
-         * To define the report descriptor. Warning: this method has to store the length of the report descriptor in reportLength.
-         *
-         * @returns pointer to the report descriptor
-         */
-         virtual uint8_t * reportDesc();
- 
-         /* USB descriptor string overrides */
-         virtual uint8_t *stringImanufacturerDesc();
-         virtual uint8_t *stringIserialDesc();
-         virtual uint8_t *stringIproductDesc();
- 
-     private:
-         int8_t _x;                       
-         int8_t _y;     
-         int8_t _z;
-         uint16_t _buttons;
-         
-         void _init();                 
-};
- 
-#endif
\ No newline at end of file

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/USBJoystick/USBJoystick.cpp	Wed Jul 23 17:53:28 2014 +0000
@@ -0,0 +1,150 @@
+/* Copyright (c) 2010-2011 mbed.org, MIT License
+* Modified Mouse code for Joystick - WH 2012
+*
+* 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
+* restriction, including without limitation the rights to use, copy, modify, merge, publish,
+* distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the
+* Software is furnished to do so, subject to the following conditions:
+*
+* The above copyright notice and this permission notice shall be included in all copies or
+* substantial portions of the Software.
+*
+* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
+* BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+ 
+#include "stdint.h"
+#include "USBJoystick.h"
+ 
+bool USBJoystick::update(int16_t x, int16_t y, int16_t z, int16_t rx, int16_t ry, uint16_t buttons) 
+{
+   _x = x;
+   _y = y;
+   _z = z;
+   _rx = rx;
+   _ry = ry;
+   _buttons = buttons;     
+ 
+   // send the report
+   return update();
+}
+ 
+bool USBJoystick::update() {
+   HID_REPORT report;
+ 
+   // Fill the report according to the Joystick Descriptor
+   report.data[0] = _buttons & 0xff;
+   report.data[1] = (_buttons >> 8) & 0xff;
+   report.data[2] = _x & 0xff;            
+   report.data[3] = _y & 0xff;            
+   report.data[4] = _z & 0xff;
+   report.data[5] = _rx & 0xff;
+   report.data[6] = _ry & 0xff;
+   report.length = 7; 
+ 
+   return sendNB(&report);
+}
+ 
+bool USBJoystick::move(int16_t x, int16_t y) {
+     _x = x;
+     _y = y;
+     return update();
+}
+
+bool USBJoystick::setZ(int16_t z) {
+    _z = z;
+    return update();
+}
+ 
+bool USBJoystick::buttons(uint16_t buttons) {
+     _buttons = buttons;
+     return update();
+}
+ 
+ 
+void USBJoystick::_init() {
+ 
+   _x = 0;                       
+   _y = 0;     
+   _z = 0;
+   _buttons = 0x0000;
+}
+ 
+ 
+uint8_t * USBJoystick::reportDesc() 
+{    
+    static uint8_t reportDescriptor[] = 
+    {         
+         USAGE_PAGE(1), 0x01,            // Generic desktop
+         USAGE(1), 0x04,                 // Joystick
+
+         COLLECTION(1), 0x01,            // Application
+      //     COLLECTION(1), 0x00,          // Physical
+           
+             USAGE_PAGE(1), 0x09,        // Buttons
+             USAGE_MINIMUM(1), 0x01,     // { buttons }
+             USAGE_MAXIMUM(1), 0x10,     // {  1-16   }
+             LOGICAL_MINIMUM(1), 0x00,   // 1-bit buttons - 0...
+             LOGICAL_MAXIMUM(1), 0x01,   // ...to 1
+             REPORT_SIZE(1), 0x01,       // 1 bit per report
+             REPORT_COUNT(1), 0x10,      // 16 reports
+             UNIT_EXPONENT(1), 0x00,     // Unit_Exponent (0)
+             UNIT(1), 0x00,              // Unit (None)                                           
+             INPUT(1), 0x02,             // Data, Variable, Absolute
+           
+             USAGE_PAGE(1), 0x01,        // Generic desktop
+             USAGE(1), 0x30,             // X
+             USAGE(1), 0x31,             // Y
+             USAGE(1), 0x32,             // Z
+             USAGE(1), 0x33,             // Rx
+             USAGE(1), 0x34,             // Ry
+             LOGICAL_MINIMUM(1), 0x81,   // each value ranges -127...
+             LOGICAL_MAXIMUM(1), 0x7f,   // ...to 127
+             REPORT_SIZE(1), 0x08,       // 8 bits per report
+             REPORT_COUNT(1), 0x05,      // 5 reports (X, Y, Z, Rx, Ry)
+             INPUT(1), 0x02,             // Data, Variable, Absolute
+
+             REPORT_COUNT(1), 0x08,      // input report count (LEDWiz messages)
+             0x09, 0x01,                 // usage
+             0x91, 0x01,                 // Output (array)
+
+     //      END_COLLECTION(0),
+         END_COLLECTION(0)
+      };
+ 
+      reportLength = sizeof(reportDescriptor);
+      return reportDescriptor;
+}
+ 
+ uint8_t * USBJoystick::stringImanufacturerDesc() {
+    static uint8_t stringImanufacturerDescriptor[] = {
+        0x10,                                            /*bLength*/
+        STRING_DESCRIPTOR,                               /*bDescriptorType 0x03*/
+        'm',0,'j',0,'r',0,'c',0,'o',0,'r',0,'p',0        /*bString iManufacturer - mjrcorp*/
+    };
+    return stringImanufacturerDescriptor;
+}
+
+uint8_t * USBJoystick::stringIserialDesc() {
+    static uint8_t stringIserialDescriptor[] = {
+        0x16,                                                           /*bLength*/
+        STRING_DESCRIPTOR,                                              /*bDescriptorType 0x03*/
+        '0',0,'1',0,'2',0,'3',0,'4',0,'5',0,'6',0,'7',0,'8',0,'9',0,    /*bString iSerial - 0123456789*/
+    };
+    return stringIserialDescriptor;
+}
+
+uint8_t * USBJoystick::stringIproductDesc() {
+    static uint8_t stringIproductDescriptor[] = {
+        0x2E,                                                       /*bLength*/
+        STRING_DESCRIPTOR,                                          /*bDescriptorType 0x03*/
+        'P',0,'i',0,'n',0,'s',0,'c',0,'a',0,'p',0,'e',0,
+        ' ',0,'C',0,'o',0,'n',0,'t',0,'r',0,'o',0,'l',0,
+        'l',0,'e',0,'r',0                                           /*String iProduct */
+    };
+    return stringIproductDescriptor;
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/USBJoystick/USBJoystick.h	Wed Jul 23 17:53:28 2014 +0000
@@ -0,0 +1,165 @@
+/* USBJoystick.h */
+/* USB device example: Joystick*/
+/* Copyright (c) 2011 ARM Limited. All rights reserved. */
+/* Modified Mouse code for Joystick - WH 2012 */
+ 
+#ifndef USBJOYSTICK_H
+#define USBJOYSTICK_H
+ 
+#include "USBHID.h"
+ 
+#define REPORT_ID_JOYSTICK  4
+ 
+/* Common usage */
+enum JOY_BUTTON {
+     JOY_B0 = 0x0001,
+     JOY_B1 = 0x0002,
+     JOY_B2 = 0x0004,
+     JOY_B3 = 0x0008,
+     JOY_B4 = 0x0010,
+     JOY_B5 = 0x0020,
+     JOY_B6 = 0x0040,
+     JOY_B7 = 0x0080,
+     JOY_B8 = 0x0100,
+     JOY_B9 = 0x0200,
+     JOY_B10 = 0x0400,
+     JOY_B11 = 0x0800,
+     JOY_B12 = 0x1000,
+     JOY_B13 = 0x2000,
+     JOY_B14 = 0x4000,
+     JOY_B15 = 0x8000
+};
+ 
+/* X, Y and T limits */
+/* These values do not directly map to screen pixels */
+/* Zero may be interpreted as meaning 'no movement' */
+#define JX_MIN_ABS    (-127)     /*!< The maximum value that we can move to the left on the x-axis */
+#define JY_MIN_ABS    (-127)     /*!< The maximum value that we can move up on the y-axis */
+#define JZ_MIN_ABS    (-127)     /*!< The minimum value for the Z axis */
+#define JX_MAX_ABS    (127)      /*!< The maximum value that we can move to the right on the x-axis */
+#define JY_MAX_ABS    (127)      /*!< The maximum value that we can move down on the y-axis */
+#define JZ_MAX_ABS    (127)      /*!< The maximum value for the Z axis */
+ 
+/**
+ *
+ * USBJoystick example
+ * @code
+ * #include "mbed.h"
+ * #include "USBJoystick.h"
+ *
+ * USBJoystick joystick;
+ *
+ * int main(void)
+ * {
+ *   while (1)
+ *   {
+ *      joystick.move(20, 0);
+ *      wait(0.5);
+ *   }
+ * }
+ *
+ * @endcode
+ *
+ *
+ * @code
+ * #include "mbed.h"
+ * #include "USBJoystick.h"
+ * #include <math.h>
+ *
+ * USBJoystick joystick;
+ *
+ * int main(void)
+ * {   
+ *   while (1) {
+ *       // Basic Joystick
+ *       joystick.update(tx, y, z, buttonBits);
+ *       wait(0.001);
+ *   }
+ * }
+ * @endcode
+ */
+ 
+ 
+class USBJoystick: public USBHID {
+   public:
+ 
+        /**
+         *   Constructor
+         *
+         * @param vendor_id Your vendor_id (default: 0x1234)
+         * @param product_id Your product_id (default: 0x0002)
+         * @param product_release Your product_release (default: 0x0001)
+         */
+         USBJoystick(uint16_t vendor_id = 0x1234, uint16_t product_id = 0x0100, uint16_t product_release = 0x0001): 
+             USBHID(8, 8, vendor_id, product_id, product_release, false)
+             { 
+                 _init();
+                 connect();
+             };
+         
+         /**
+         * Write a state of the mouse
+         *
+         * @param x x-axis position
+         * @param y y-axis position
+         * @param z z-axis position
+         * @param buttons buttons state, as a bit mask (combination with '|' of JOY_Bn values)
+         * @returns true if there is no error, false otherwise
+         */
+         bool update(int16_t x, int16_t y, int16_t z, int16_t rx, int16_t ry, uint16_t buttons);
+ 
+         /**
+         * Write a state of the mouse
+         *
+         * @returns true if there is no error, false otherwise
+         */
+         bool update();
+ 
+         /**
+         * Move the cursor to (x, y)
+         *
+         * @param x x-axis position
+         * @param y y-axis position
+         * @returns true if there is no error, false otherwise
+         */
+         bool move(int16_t x, int16_t y);
+         
+         /**
+         * Set the z position
+         *
+         * @param z z-axis osition
+         */
+         bool setZ(int16_t z);
+         
+         /**
+         * Press one or several buttons
+         *
+         * @param buttons button state, as a bitwise combination of JOY_Bn values
+         * @returns true if there is no error, false otherwise
+         */
+         bool buttons(uint16_t buttons);
+         
+         /*
+         * To define the report descriptor. Warning: this method has to store the length of the report descriptor in reportLength.
+         *
+         * @returns pointer to the report descriptor
+         */
+         virtual uint8_t * reportDesc();
+ 
+         /* USB descriptor string overrides */
+         virtual uint8_t *stringImanufacturerDesc();
+         virtual uint8_t *stringIserialDesc();
+         virtual uint8_t *stringIproductDesc();
+ 
+     private:
+         int8_t _x;                       
+         int8_t _y;     
+         int8_t _z;
+         int8_t _rx;
+         int8_t _ry;
+         uint16_t _buttons;
+         
+         void _init();                 
+};
+ 
+#endif
\ No newline at end of file

--- a/main.cpp	Tue Jul 22 04:33:47 2014 +0000
+++ b/main.cpp	Wed Jul 23 17:53:28 2014 +0000
@@ -12,20 +12,16 @@
     MyUSBJoystick(uint16_t vendor_id, uint16_t product_id, uint16_t product_release) 
         : USBJoystick(vendor_id, product_id, product_release)
     {
-        connected_ = false;
         suspended_ = false;
     }
     
-    int isConnected() const { return connected_; }
+    int isConnected() { return configured(); }
     int isSuspended() const { return suspended_; }
     
 protected:
-    virtual void connectStateChanged(unsigned int connected) 
-        { connected_ = connected; }
     virtual void suspendStateChanged(unsigned int suspended)
         { suspended_ = suspended; }
 
-    int connected_;
     int suspended_; 
 };
 
@@ -117,6 +113,104 @@
     } d;
 };
 
+// Accelerometer handler
+const int MMA8451_I2C_ADDRESS = (0x1d<<1);
+class Accel
+{
+public:
+    Accel(PinName sda, PinName scl, int i2cAddr, PinName irqPin)
+        : mma_(sda, scl, i2cAddr), intIn_(irqPin)
+    {
+        // set the initial ball velocity to zero
+        vx_ = vy_ = 0;
+        
+        // set the initial raw acceleration reading to zero
+        xRaw_ = yRaw_ = 0;
+
+        // enable the interrupt
+        mma_.setInterruptMode(irqPin == PTA14 ? 1 : 2);
+        
+        // set up the interrupt handler
+        intIn_.rise(this, &Accel::isr);
+        
+        // read the current registers to clear the data ready flag
+        float z;
+        mma_.getAccXYZ(xRaw_, yRaw_, z);
+
+        // start our timers
+        tGet_.start();
+        tInt_.start();
+    }
+    
+    void get(float &x, float &y, float &rx, float &ry) 
+    {
+         // disable interrupts while manipulating the shared data
+         __disable_irq();
+         
+         // read the shared data and store locally for calculations
+         float vx = vx_, vy = vy_, xRaw = xRaw_, yRaw = yRaw_;
+
+         // reset the velocity
+         vx_ = vy_ = 0;
+         
+         // get the time since the last get() sample
+         float dt = tGet_.read_us()/1.0e6;
+         tGet_.reset();
+         
+         // done manipulating the shared data
+         __enable_irq();
+         
+         // calculate the acceleration since the last get(): a = dv/dt
+         x = vx/dt;
+         y = vy/dt;         
+         
+         // return the raw accelerometer data in rx,ry
+         rx = xRaw;
+         ry = yRaw;
+     }    
+    
+private:
+    // interrupt handler
+    void isr()
+    {
+        // Read the axes.  Note that we have to read all three axes
+        // (even though we only really use x and y) in order to clear
+        // the "data ready" status bit in the accelerometer.  The
+        // interrupt only occurs when the "ready" bit transitions from
+        // off to on, so we have to make sure it's off.
+        float z;
+        mma_.getAccXYZ(xRaw_, yRaw_, z);
+        
+        // calculate the time since the last interrupt
+        float dt = tInt_.read_us()/1.0e6;
+        tInt_.reset();
+        
+        // Accelerate the model ball: v = a*dt.  Assume that the raw
+        // data from the accelerometer reflects the average physical
+        // acceleration over the interval since the last sample.
+        vx_ += xRaw_ * dt;
+        vy_ += yRaw_ * dt;
+    }
+    
+    // current modeled ball velocity
+    float vx_, vy_;
+    
+    // last raw axis readings
+    float xRaw_, yRaw_;
+    
+    // underlying accelerometer object
+    MMA8451Q mma_;
+    
+    // interrupt router
+    InterruptIn intIn_;
+    
+    // timer for measuring time between get() samples
+    Timer tGet_;
+    
+    // timer for measuring time between interrupts
+    Timer tInt_;
+};
+
 int main(void)
 {
     // turn off our on-board indicator LED
@@ -188,13 +282,12 @@
     // Create the joystick USB client.  Light the on-board indicator LED
     // red while connecting, and change to green after we connect.
     led1 = 0;
-    MyUSBJoystick js(0xFAFA, 0x00F7, 0x0001);
+    MyUSBJoystick js(0xFAFA, 0x00F7, 0x0003);
     led1 = 1;
     led2 = 0;
 
     // create the accelerometer object
-    const int MMA8451_I2C_ADDRESS = (0x1d<<1);
-    MMA8451Q accel(PTE25, PTE24, MMA8451_I2C_ADDRESS);
+    Accel accel(PTE25, PTE24, MMA8451_I2C_ADDRESS, PTA15);
     
     // create the CCD array object
     TSL1410R ccd(PTE20, PTE21, PTB0);
@@ -362,13 +455,16 @@
             newCalBtnLit = false;
             break;
         }
+        
+        // light or flash the external calibration button LED, and 
+        // do the same with the on-board blue LED
         if (calBtnLit != newCalBtnLit)
         {
             calBtnLit = newCalBtnLit;
             if (calBtnLit) {
                 calBtnLed = 1;
-                led1 = 0;
-                led2 = 0;
+                led1 = 1;
+                led2 = 1;
                 led3 = 1;
             }
             else {
@@ -447,8 +543,8 @@
         }
         
         // read the accelerometer
-        float xa, ya;
-        accel.getAccXY(xa, ya);
+        float xa, ya, rxa, rya;
+        accel.get(xa, ya, rxa, rya);
         
         // check for auto-centering every so often
         if (acTimer.read_ms() - t0ac > 1000) 
@@ -521,17 +617,13 @@
             }
         }
 
-        // Send the status report.  Note one of the axes needs to be
-        // reversed, because the native accelerometer reports seem to
-        // assume that the card is component side down; we have to
-        // reverse one or the other axis to account for the reversed
-        // coordinate system.  It doesn't really matter which one,
-        // but reversing Y seems to give intuitive results when viewed
-        // in the Windows joystick control panel.  Note that the 
-        // coordinate system we report is ultimately arbitrary, since
-        // Visual Pinball has preference settings that let us set up
-        // axis reversals and a global rotation for the joystick.
-        js.update(x, -y, z, 0);
+        // Send the status report.  It doesn't really matter what
+        // coordinate system we use, since Visual Pinball has config
+        // options for rotations and axis reversals, but reversing y
+        // at the device level seems to produce the most intuitive 
+        // results for the Windows joystick control panel view, which
+        // is an easy way to check that the device is working.
+        js.update(x, -y, z, int(rxa*127), int(rya*127), 0);
         
         // show a heartbeat flash in blue every so often if not in 
         // calibration mode
@@ -566,7 +658,7 @@
                 hb = !hb;
                 led1 = (hb ? 0 : 1);
                 led2 = 0;
-                led3 = 0;
+                led3 = 1;
             }
             
             // reset the heartbeat timer