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.cpp

Revision:
7:8aa5123d403f
Parent:
5:b3d0abd97e55
Child:
8:89272163f395
diff -r b3d0abd97e55 -r 8aa5123d403f MMA8452.cpp
--- a/MMA8452.cpp	Wed Oct 16 18:55:16 2013 +0000
+++ b/MMA8452.cpp	Thu Oct 17 09:40:10 2013 +0000
@@ -240,7 +240,7 @@
     xaxis_register[0] = OUT_X_MSB;                          // this is the register we want to get data from
     //signed short s = 0;
     
-    if(m_i2c.write(mcu_address,xaxis_register,1) == 0)
+    if(m_i2c.write(mcu_address,xaxis_register,1,true) == 0)
     {
         if(m_i2c.read(mcu_address,xaxis_buffer,2) == 0)
         {
@@ -280,7 +280,7 @@
     yaxis_register[0] = OUT_Y_MSB;                          // this is the register we want to get data from
     //signed short s = 0;
     
-    if(m_i2c.write(mcu_address,yaxis_register,1) == 0)
+    if(m_i2c.write(mcu_address,yaxis_register,1,true) == 0)
     {
         if(m_i2c.read(mcu_address,yaxis_buffer,2) == 0)
         {
@@ -321,7 +321,7 @@
     zaxis_register[0] = OUT_Z_MSB;                          // this is the register we want to get data from
     //signed short s = 0;
     
-    if(m_i2c.write(mcu_address,zaxis_register,1) == 0)
+    if(m_i2c.write(mcu_address,zaxis_register,1,true) == 0)
     {
         //if(m_i2c.read(mcu_address,zaxis_buffer,2) == 0)
         if(m_i2c.read(mcu_address,zaxis,2) == 0)