Ashley Mills / MMA8452

Library for driving the MMA8452 accelerometer over I2C

Dependents:   MMA8452_Test MMA8452_Demo Dualing_Tanks IMU-Controlled_MP3_Player ... more

Here is a simple example:

#include "mbed.h"
#include "MMA8452.h"

int main() {
   Serial pc(USBTX,USBRX);
   pc.baud(115200);
   double x = 0, y = 0, z = 0;

   MMA8452 acc(p28, p27, 40000);
   acc.setBitDepth(MMA8452::BIT_DEPTH_12);
   acc.setDynamicRange(MMA8452::DYNAMIC_RANGE_4G);
   acc.setDataRate(MMA8452::RATE_100);
   
   while(1) {
      if(!acc.isXYZReady()) {
         wait(0.01);
         continue;
      }
      acc.readXYZGravity(&x,&y,&z);
      pc.printf("Gravities: %lf %lf %lf\r\n",x,y,z);
   }
}

An easy way to test that this actually works is to run the loop above and hold the MMA8452 parallel to the ground along the respective axis (and upsidedown in each axis). You will see 1G on the respective axis and 0G on the others.

Diff: MMA8452.h

Revision:
8:89272163f395
Parent:
6:f6bde04bf8be
Child:
9:dfb0f6a7a455
--- a/MMA8452.h	Thu Oct 17 09:40:10 2013 +0000
+++ b/MMA8452.h	Thu Oct 17 10:08:51 2013 +0000
@@ -115,11 +115,6 @@
 #define SR_STATUS 0x08          // Auto-Wake and Active Mode Portrait/Landscape Samples per Seconds Register (Read/Write)
 #define PDET_STATUS 0x09        // Tap/Pulse Detection Register (Read/Write)
 #define PD_STATUS 0xA           // Tap/Pulse Debounce Count Register (Read/Write)
-
-
-
-
-
  
 class Accelerometer_MMA8452         
 {        
@@ -139,9 +134,7 @@
         *
         */
       ~Accelerometer_MMA8452();
-      
-      
-      
+            
       /** Get system mode of the MMA8452 (not required)
         *   returns 0 for success in reading the system mode of the chip
         *   returns 1 for failure in reading the system mode of the chip
@@ -152,7 +145,6 @@
       int get_SystemMode(int& deviceSystemMode);
       
       
-      
       /** Get status of the MMA8452 (not required)
         *   returns 0 for success in reading the status of the chip
         *   returns 1 for failure in reading the status of  the chip
@@ -163,7 +155,6 @@
         *   
       */
       int get_Status(int& deviceStatus);
-     
       
       
       /** Activate the MMA8452 (required)
@@ -176,7 +167,6 @@
       int activate();
  
  
- 
        /** Standby the MMA8452 (not required)
         *   returns 0 for success in activating the chip
         *   returns 1 for failure in activating the chip
@@ -195,7 +185,7 @@
         *   This will return the state of the control register 1. This holds and sets values for auto wake, sleep mode
         *   output data rate, fast read mode and active/standby. More info on 6.7 of pdf for MMA8452 Freescale doc.
       */
-      int get_CTRL_Reg1(int& CTRL_Reg); 
+      int get_CTRL_Reg1(int* CTRL_Reg);
       
       
        /** Initialization of device MMA8452 (required)
@@ -257,8 +247,13 @@
       
    
     private:
+      int read_raw(char src, char *dst, int len);
+    
+    
       I2C m_i2c;
       int m_frequency;
+      int _readAddress;
+      int _writeAddress;
          
 };