Seeed / Grove_3-Axis_Digital_Accelerometer_MMA7660FC_Library

3-Axis Digital Accelerometer is the key part in projects like orientation detection, gesture detection and Motion detection. This 3-Asix Digital Accelerometer(±1.5g) is based on Freescale's low power consumption module, MMA7660FC. It features up to 10,000g high shock surviability and configurable Samples per Second rate. For generous applications that don't require too large measurement range, this is a great choice because it's durable, energy saving and cost-efficient.

Fork of Grove_3-Axis_Digital_Accelerometer_MMA7660FC_Library by Austin Blackstone

Files at this revision

API Documentation at this revision

Revision 1:08f271727b67, committed 2019-07-23

Comitter:
c1728p9
Date:
Tue Jul 23 21:39:37 2019 +0000
Parent:
0:cc40c3196635
Commit message:
Correctly handle negative acceleration values

Changed in this revision

MMA7660.h Show annotated file Show diff for this revision Revisions of this file
MMA7660FC.cpp Show annotated file Show diff for this revision Revisions of this file 
diff -r cc40c3196635 -r 08f271727b67 MMA7660.h
--- a/MMA7660.h	Fri Sep 05 23:14:35 2014 +0000
+++ b/MMA7660.h	Tue Jul 23 21:39:37 2019 +0000
@@ -65,6 +65,7 @@
     void setMode(uint8_t mode);
     void setSampleRate(uint8_t rate);
     void getXYZ(int8_t *x,int8_t *y,int8_t *z);
+    void getSignedXYZ(int8_t *x,int8_t *y,int8_t *z);
     void getAcceleration(float *ax,float *ay,float *az);
 };
 

diff -r cc40c3196635 -r 08f271727b67 MMA7660FC.cpp
--- a/MMA7660FC.cpp	Fri Sep 05 23:14:35 2014 +0000
+++ b/MMA7660FC.cpp	Tue Jul 23 21:39:37 2019 +0000
@@ -119,11 +119,24 @@
     *z = ((char)(val[2]<<2))/4;
 }
 
+void MMA7660::getSignedXYZ(int8_t *x,int8_t *y,int8_t *z)
+{
+    int8_t val[3];
+    getXYZ(val + 0, val + 1, val + 2);
+    
+    for (size_t i = 0; i < sizeof(val); i++) {
+        val[i] = val[i] >= 32 ? val[i] - 64 : val[i];
+    }
+    *x = val[0];
+    *y = val[1];
+    *z = val[2];
+}
+
 void MMA7660::getAcceleration(float *ax,float *ay,float *az)
 {
     int8_t x,y,z;
-    getXYZ(&x,&y,&z);
-    *ax = x/21.00;
-    *ay = y/21.00;
-    *az = z/21.00;
+    getSignedXYZ(&x,&y,&z);
+    *ax = x/21.33;
+    *ay = y/21.33;
+    *az = z/21.33;
 }