Jim Carver / FXOS8700Q

A basic library for the FXOS8700Q combination accelerometer / magnetometer

Dependencies:   MotionSensor

Dependents:   K64F_eCompass_LCD Hello_FXOS8700Q rtos_compass K64F_eCompass ... more

This library supports the 6 axis combination Accelerometer / Magnetometer. Functions are provided to retrieve data in raw 16 bit signed integers or unit converted G's and micro-teslas

Files at this revision

API Documentation at this revision

Revision 9:5553a64d0762, committed 2014-05-07

Comitter:
JimCarver
Date:
Wed May 07 18:08:08 2014 +0000
Parent:
8:52116f8fb3da
Commit message:
Minor change to improve efficiency to I2C usage

Changed in this revision

FXOS8700Q.cpp Show annotated file Show diff for this revision Revisions of this file
FXOS8700Q.h Show annotated file Show diff for this revision Revisions of this file 
--- a/FXOS8700Q.cpp	Sat Apr 26 01:36:41 2014 +0000
+++ b/FXOS8700Q.cpp	Wed May 07 18:08:08 2014 +0000
@@ -19,6 +19,8 @@
 #include "FXOS8700Q.h"
 #define UINT14_MAX        16383
 
+uint8_t SensorBuffer[12];
+int     MagReadStatus;
 
 FXOS8700Q_acc::FXOS8700Q_acc(PinName sda, PinName scl, int addr) : m_i2c(sda, scl), m_addr(addr) {
     // activate the peripheral
@@ -37,6 +39,7 @@
     data[0] = FXOS8700Q_CTRL_REG1;
     data[1] = 0x1C;
     writeRegs(data, 2);
+    MagReadStatus = 0;
 }
 
 FXOS8700Q_acc::~FXOS8700Q_acc() { }
@@ -47,6 +50,7 @@
     data[1] |= 0x01;
     data[0] = FXOS8700Q_CTRL_REG1;
     writeRegs(data, 2);
+    MagReadStatus = 0;
 }
 
 void FXOS8700Q_acc::disable(void) {
@@ -55,6 +59,7 @@
     data[1] &= 0xFE;
     data[0] = FXOS8700Q_CTRL_REG1;
     writeRegs(data, 2);
+    MagReadStatus = 0;
 }
 
 
@@ -102,44 +107,45 @@
 
 void FXOS8700Q_acc::getAxis(MotionSensorDataUnits &data) {
     int16_t acc, t[3];
-    uint8_t res[6];
-   readRegs(FXOS8700Q_OUT_X_MSB, res, 6);
 
-    acc = (res[0] << 6) | (res[1] >> 2);
+   readRegs(FXOS8700Q_OUT_X_MSB, SensorBuffer, 12);
+
+    acc = (SensorBuffer[0] << 6) | (SensorBuffer[1] >> 2);
     if (acc > UINT14_MAX/2)
         acc -= UINT14_MAX;
     t[0] = acc;
-    acc = (res[2] << 6) | (res[3] >> 2);
+    acc = (SensorBuffer[2] << 6) | (SensorBuffer[3] >> 2);
     if (acc > UINT14_MAX/2)
         acc -= UINT14_MAX;
     t[1] = acc;
-    acc = (res[4] << 6) | (res[5] >> 2);
+    acc = (SensorBuffer[4] << 6) | (SensorBuffer[5] >> 2);
     if (acc > UINT14_MAX/2)
         acc -= UINT14_MAX;
     t[2] = acc;
     data.x = ((float) t[0]) / 4096.0f;
     data.y = ((float) t[1]) / 4096.0f;
     data.z = ((float) t[2]) / 4096.0f;
+    MagReadStatus = 1;
 }
 
 
 void FXOS8700Q_acc::getAxis(MotionSensorDataCounts &data) {
     int16_t acc;
-    uint8_t res[6];
-    readRegs(FXOS8700Q_OUT_X_MSB, res, 6);
+    readRegs(FXOS8700Q_OUT_X_MSB, SensorBuffer, 12);
 
-    acc = (res[0] << 6) | (res[1] >> 2);
+    acc = (SensorBuffer[0] << 6) | (SensorBuffer[1] >> 2);
     if (acc > UINT14_MAX/2)
         acc -= UINT14_MAX;
     data.x = acc;
-    acc = (res[2] << 6) | (res[3] >> 2);
+    acc = (SensorBuffer[2] << 6) | (SensorBuffer[3] >> 2);
     if (acc > UINT14_MAX/2)
         acc -= UINT14_MAX;
     data.y = acc;
-    acc = (res[4] << 6) | (res[5] >> 2);
+    acc = (SensorBuffer[4] << 6) | (SensorBuffer[5] >> 2);
     if (acc > UINT14_MAX/2)
         acc -= UINT14_MAX;
     data.z = acc;
+    MagReadStatus = 1;
 }
 
 void FXOS8700Q_acc::readRegs(int addr, uint8_t * data, int len) {
@@ -184,6 +190,7 @@
     data[0] = FXOS8700Q_CTRL_REG1;
     data[1] = 0x18;//0x1D;
     writeRegs(data, 2);
+    MagReadStatus = 0;
 }
 
 FXOS8700Q_mag::~FXOS8700Q_mag() { }
@@ -194,6 +201,7 @@
     data[1] |= 0x01;
     data[0] = FXOS8700Q_CTRL_REG1;
     writeRegs(data, 2);
+    MagReadStatus = 0;
 }
 
 void FXOS8700Q_mag::disable(void) {
@@ -202,6 +210,7 @@
     data[1] &= 0xFE;
     data[0] = FXOS8700Q_CTRL_REG1;
     writeRegs(data, 2);
+    MagReadStatus = 0;
 }
 
 
@@ -250,12 +259,17 @@
 void FXOS8700Q_mag::getAxis(MotionSensorDataUnits &data) {
     int16_t t[3];
     uint8_t res[6];
-   readRegs(FXOS8700Q_M_OUT_X_MSB, res, 6);
-
-    t[0] = (res[0] << 8) | res[1];
-    t[1] = (res[2] << 8) | res[3];
-    t[2] = (res[4] << 8) | res[5];
-
+    
+   if(MagReadStatus) {
+        t[0] = (SensorBuffer[6] << 8) | SensorBuffer[7];
+        t[1] = (SensorBuffer[8] << 8) | SensorBuffer[9];
+        t[2] = (SensorBuffer[10] << 8) | SensorBuffer[11];        
+        } else {
+        readRegs(FXOS8700Q_M_OUT_X_MSB, res, 6);
+        t[0] = (res[0] << 8) | res[1];
+        t[1] = (res[2] << 8) | res[3];
+        t[2] = (res[4] << 8) | res[5];
+        }
     data.x = ((float) t[0]) * 0.1f;
     data.y = ((float) t[1]) * 0.1f;
     data.z = ((float) t[2]) * 0.1f;
@@ -263,7 +277,7 @@
 
 
 void FXOS8700Q_mag::getAxis(MotionSensorDataCounts &data) {
-    int16_t acc;
+
     uint8_t res[6];
     readRegs(FXOS8700Q_M_OUT_X_MSB, res, 6);
 

--- a/FXOS8700Q.h	Sat Apr 26 01:36:41 2014 +0000
+++ b/FXOS8700Q.h	Wed May 07 18:08:08 2014 +0000
@@ -139,7 +139,9 @@
 private:
   I2C m_i2c;
   int m_addr;
-
+  char sbuf[12];
+  int sstatus;
+  
   void writeRegs(uint8_t * data, int len);
   int16_t getAccAxis(uint8_t addr);