ENGO333_MMA7660.cpp

00001 #include "ENGO333_MMA7660.h"
00002 
00003 const float GRAVITY = 9.8086;
00004 
00005 ENGO333_MMA7660::ENGO333_MMA7660() : i2c(p28, p27)
00006 {
00007     SetActiveMode();
00008     SetSamplingRateAM(MMA7660_AMSR8);
00009     measAccel[0] = measAccel[1] = measAccel[2] = 0;
00010 }
00011 
00012 bool ENGO333_MMA7660::TestConnection() 
00013 {
00014     char data[3] = {128, 128, 128};
00015     bool alert;
00016 
00017     // Check data validity
00018     alert = false;
00019     i2c.readBytes(MMA7660_ADDRESS, MMA7660_XOUT_REG, data, 3);
00020     for (int i = 0; i < 3; ++i) {
00021         if (data[i] > 63)
00022             alert = true;
00023     }
00024     
00025     if (alert == false) {
00026         return true;
00027     } else {
00028         return false;
00029     }
00030 }
00031 
00032 void ENGO333_MMA7660::SetActiveMode()
00033 {
00034     i2c.writeOneByte(MMA7660_ADDRESS, MMA7660_MODE_REG, 0x01);
00035 }
00036 
00037 void ENGO333_MMA7660::SetSamplingRateAM(MMA7660_AMSR_t samplingRate)
00038 {
00039     char oldValue, newValue;
00040     oldValue = i2c.readOneByte(MMA7660_ADDRESS, MMA7660_SR_REG);
00041     oldValue = oldValue & 0x07;
00042     newValue = oldValue | samplingRate;
00043     i2c.writeOneByte(MMA7660_ADDRESS, MMA7660_SR_REG, newValue);
00044 }
00045 
00046 void ENGO333_MMA7660::ReadAccelerometers()
00047 {
00048     char data[3];
00049     bool alert;
00050 
00051     // Check data validity
00052     do {
00053         alert = false;
00054         i2c.readBytes(MMA7660_ADDRESS, MMA7660_XOUT_REG, data, 3);
00055         for (int i = 0; i < 3; ++i) {
00056             if (data[i] > 63)
00057                 alert = true;
00058             if (data[i] > 31)
00059                 data[i] += 128 + 64;
00060         }
00061     } while (alert);
00062     
00063     measAccel[0] = (signed char)(data[0]) / MMA7660_SCALE * GRAVITY;
00064     measAccel[1] = (signed char)(data[1]) / MMA7660_SCALE * GRAVITY;
00065     measAccel[2] = (signed char)(data[2]) / MMA7660_SCALE * GRAVITY;
00066 }
00067 
00068 float ENGO333_MMA7660::GetAccelX() const
00069 {
00070     return measAccel[0];
00071 }
00072 
00073 float ENGO333_MMA7660::GetAccelY() const
00074 {
00075     return measAccel[1];
00076 }
00077 
00078 float ENGO333_MMA7660::GetAccelZ() const
00079 {
00080     return measAccel[2];
00081 }
00082