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

FXOS8700Q.cpp@0:2562215f5bc0, 2014-04-07 (annotated)

Committer:
JimCarver
Date:
Mon Apr 07 00:58:50 2014 +0000
Revision:
0:2562215f5bc0
Child:
1:8b53edef272f
Rev 0.1 Simple operation of just X, Y, Z values in floating point G's and micro-teslas

Who changed what in which revision?

UserRevisionLine numberNew contents of line
JimCarver 0:2562215f5bc0 1 #include "FXOS8700Q.h"
JimCarver 0:2562215f5bc0 2
JimCarver 0:2562215f5bc0 3
JimCarver 0:2562215f5bc0 4 FXOS8700Q::FXOS8700Q(PinName sda, PinName scl) : _i2c(sda, scl) {
JimCarver 0:2562215f5bc0 5
JimCarver 0:2562215f5bc0 6 begin();
JimCarver 0:2562215f5bc0 7 }
JimCarver 0:2562215f5bc0 8
JimCarver 0:2562215f5bc0 9 void FXOS8700Q::RegRead( char reg, char * d, int len) {
JimCarver 0:2562215f5bc0 10 char cmd[1];
JimCarver 0:2562215f5bc0 11 cmd[0] = reg;
JimCarver 0:2562215f5bc0 12 char i2c_addr = FXOS8700CQ_SLAVE_ADDR;
JimCarver 0:2562215f5bc0 13 _i2c.write( i2c_addr, cmd, 1);
JimCarver 0:2562215f5bc0 14 _i2c.read ( i2c_addr, d, len);
JimCarver 0:2562215f5bc0 15 }
JimCarver 0:2562215f5bc0 16
JimCarver 0:2562215f5bc0 17 void FXOS8700Q::begin(void)
JimCarver 0:2562215f5bc0 18 {
JimCarver 0:2562215f5bc0 19 char data[2];
JimCarver 0:2562215f5bc0 20 // write 0000 0000 = 0x00 to accelerometer control register 1 to place FXOS8700CQ into
JimCarver 0:2562215f5bc0 21 // standby
JimCarver 0:2562215f5bc0 22 // [7-1] = 0000 000
JimCarver 0:2562215f5bc0 23 // [0]: active=0
JimCarver 0:2562215f5bc0 24 data[0] = FXOS8700CQ_CTRL_REG1;
JimCarver 0:2562215f5bc0 25 data[1] = 0x00;
JimCarver 0:2562215f5bc0 26 _i2c.write( FXOS8700CQ_SLAVE_ADDR, data, 2);
JimCarver 0:2562215f5bc0 27
JimCarver 0:2562215f5bc0 28 // write 0001 1111 = 0x1F to magnetometer control register 1
JimCarver 0:2562215f5bc0 29 // [7]: m_acal=0: auto calibration disabled
JimCarver 0:2562215f5bc0 30 // [6]: m_rst=0: no one-shot magnetic reset
JimCarver 0:2562215f5bc0 31 // [5]: m_ost=0: no one-shot magnetic measurement
JimCarver 0:2562215f5bc0 32 // [4-2]: m_os=111=7: 8x oversampling (for 200Hz) to reduce magnetometer noise
JimCarver 0:2562215f5bc0 33 // [1-0]: m_hms=11=3: select hybrid mode with accel and magnetometer active
JimCarver 0:2562215f5bc0 34 data[0] = FXOS8700CQ_M_CTRL_REG1;
JimCarver 0:2562215f5bc0 35 data[1] = 0x03; //0x1F;
JimCarver 0:2562215f5bc0 36 _i2c.write( FXOS8700CQ_SLAVE_ADDR, data, 2);
JimCarver 0:2562215f5bc0 37
JimCarver 0:2562215f5bc0 38 // write 0010 0000 = 0x20 to magnetometer control register 2
JimCarver 0:2562215f5bc0 39 // [7]: reserved
JimCarver 0:2562215f5bc0 40 // [6]: reserved
JimCarver 0:2562215f5bc0 41 // [5]: hyb_autoinc_mode=1 to map the magnetometer registers to follow the
JimCarver 0:2562215f5bc0 42 // accelerometer registers
JimCarver 0:2562215f5bc0 43 // [4]: m_maxmin_dis=0 to retain default min/max latching even though not used
JimCarver 0:2562215f5bc0 44 // [3]: m_maxmin_dis_ths=0
JimCarver 0:2562215f5bc0 45 // [2]: m_maxmin_rst=0
JimCarver 0:2562215f5bc0 46 // [1-0]: m_rst_cnt=00 to enable magnetic reset each cycle
JimCarver 0:2562215f5bc0 47 data[0] = FXOS8700CQ_M_CTRL_REG2;
JimCarver 0:2562215f5bc0 48 data[1] = 0x20;
JimCarver 0:2562215f5bc0 49 _i2c.write( FXOS8700CQ_SLAVE_ADDR, data, 2);
JimCarver 0:2562215f5bc0 50
JimCarver 0:2562215f5bc0 51 // write 0000 0001= 0x01 to XYZ_DATA_CFG register
JimCarver 0:2562215f5bc0 52 // [7]: reserved
JimCarver 0:2562215f5bc0 53 // [6]: reserved
JimCarver 0:2562215f5bc0 54 // [5]: reserved
JimCarver 0:2562215f5bc0 55 // [4]: hpf_out=0
JimCarver 0:2562215f5bc0 56 // [3]: reserved
JimCarver 0:2562215f5bc0 57 // [2]: reserved
JimCarver 0:2562215f5bc0 58 // [1-0]: fs=00 for accelerometer range of +/-2g range with 0.244mg/LSB
JimCarver 0:2562215f5bc0 59 data[0] = FXOS8700CQ_XYZ_DATA_CFG;
JimCarver 0:2562215f5bc0 60 data[1] = 0x00;
JimCarver 0:2562215f5bc0 61 _i2c.write( FXOS8700CQ_SLAVE_ADDR, data, 2);
JimCarver 0:2562215f5bc0 62
JimCarver 0:2562215f5bc0 63 // write 0000 1101 = 0x0D to accelerometer control register 1
JimCarver 0:2562215f5bc0 64 // [7-6]: aslp_rate=00
JimCarver 0:2562215f5bc0 65 // [5-3]: dr=011 for 50Hz data rate (when in hybrid mode)
JimCarver 0:2562215f5bc0 66 // [2]: lnoise=1 for low noise mode
JimCarver 0:2562215f5bc0 67 // [1]: f_read=0 for normal 16 bit reads
JimCarver 0:2562215f5bc0 68 // [0]: active=1 to take the part out of standby and enable sampling
JimCarver 0:2562215f5bc0 69 data[0] = FXOS8700CQ_CTRL_REG1;
JimCarver 0:2562215f5bc0 70 data[1] = 0x19;//0x1D;
JimCarver 0:2562215f5bc0 71 _i2c.write( FXOS8700CQ_SLAVE_ADDR, data, 2);
JimCarver 0:2562215f5bc0 72 }
JimCarver 0:2562215f5bc0 73
JimCarver 0:2562215f5bc0 74 void FXOS8700Q::ReadXYZ(float * a, float * m)
JimCarver 0:2562215f5bc0 75 {
JimCarver 0:2562215f5bc0 76 char d[13];
JimCarver 0:2562215f5bc0 77 int16_t t[6];
JimCarver 0:2562215f5bc0 78
JimCarver 0:2562215f5bc0 79 RegRead( FXOS8700CQ_STATUS, d, 13);
JimCarver 0:2562215f5bc0 80 t[0] = ((d[1] * 256) + ((unsigned short) d[2]));
JimCarver 0:2562215f5bc0 81 t[1] = ((d[3] * 256) + ((unsigned short) d[4]));
JimCarver 0:2562215f5bc0 82 t[2] = ((d[5] * 256) + ((unsigned short) d[6]));
JimCarver 0:2562215f5bc0 83 t[3] = ((d[7] * 256) + ((unsigned short) d[8]));
JimCarver 0:2562215f5bc0 84 t[4] = ((d[9] * 256) + ((unsigned short) d[10]));
JimCarver 0:2562215f5bc0 85 t[5] = ((d[11] * 256) + ((unsigned short) d[12]));
JimCarver 0:2562215f5bc0 86
JimCarver 0:2562215f5bc0 87 a[0] = (float) t[0] / 16384.0;
JimCarver 0:2562215f5bc0 88 a[1] = (float) t[1] / 16384.0;
JimCarver 0:2562215f5bc0 89 a[2] = (float) t[2] / 16384.0;
JimCarver 0:2562215f5bc0 90 m[0] = (float) t[3] / 10.0;
JimCarver 0:2562215f5bc0 91 m[1] = (float) t[4] / 10.0;
JimCarver 0:2562215f5bc0 92 m[2] = (float) t[5] / 10.0;
JimCarver 0:2562215f5bc0 93 }
JimCarver 0:2562215f5bc0 94