A basic library for the FXOS8700Q combination accelerometer / magnetometer
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
Revision 0:2562215f5bc0, committed 2014-04-07
- Comitter:
- JimCarver
- Date:
- Mon Apr 07 00:58:50 2014 +0000
- Child:
- 1:8b53edef272f
- Commit message:
- Rev 0.1 Simple operation of just X, Y, Z values in floating point G's and micro-teslas
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 |
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/FXOS8700Q.cpp Mon Apr 07 00:58:50 2014 +0000 @@ -0,0 +1,94 @@ +#include "FXOS8700Q.h" + + +FXOS8700Q::FXOS8700Q(PinName sda, PinName scl) : _i2c(sda, scl) { + + begin(); +} + +void FXOS8700Q::RegRead( char reg, char * d, int len) { + char cmd[1]; + cmd[0] = reg; + char i2c_addr = FXOS8700CQ_SLAVE_ADDR; + _i2c.write( i2c_addr, cmd, 1); + _i2c.read ( i2c_addr, d, len); +} + +void FXOS8700Q::begin(void) +{ + char data[2]; + // write 0000 0000 = 0x00 to accelerometer control register 1 to place FXOS8700CQ into + // standby + // [7-1] = 0000 000 + // [0]: active=0 + data[0] = FXOS8700CQ_CTRL_REG1; + data[1] = 0x00; + _i2c.write( FXOS8700CQ_SLAVE_ADDR, data, 2); + + // write 0001 1111 = 0x1F to magnetometer control register 1 + // [7]: m_acal=0: auto calibration disabled + // [6]: m_rst=0: no one-shot magnetic reset + // [5]: m_ost=0: no one-shot magnetic measurement + // [4-2]: m_os=111=7: 8x oversampling (for 200Hz) to reduce magnetometer noise + // [1-0]: m_hms=11=3: select hybrid mode with accel and magnetometer active + data[0] = FXOS8700CQ_M_CTRL_REG1; + data[1] = 0x03; //0x1F; + _i2c.write( FXOS8700CQ_SLAVE_ADDR, data, 2); + + // write 0010 0000 = 0x20 to magnetometer control register 2 + // [7]: reserved + // [6]: reserved + // [5]: hyb_autoinc_mode=1 to map the magnetometer registers to follow the + // accelerometer registers + // [4]: m_maxmin_dis=0 to retain default min/max latching even though not used + // [3]: m_maxmin_dis_ths=0 + // [2]: m_maxmin_rst=0 + // [1-0]: m_rst_cnt=00 to enable magnetic reset each cycle + data[0] = FXOS8700CQ_M_CTRL_REG2; + data[1] = 0x20; + _i2c.write( FXOS8700CQ_SLAVE_ADDR, data, 2); + + // write 0000 0001= 0x01 to XYZ_DATA_CFG register + // [7]: reserved + // [6]: reserved + // [5]: reserved + // [4]: hpf_out=0 + // [3]: reserved + // [2]: reserved + // [1-0]: fs=00 for accelerometer range of +/-2g range with 0.244mg/LSB + data[0] = FXOS8700CQ_XYZ_DATA_CFG; + data[1] = 0x00; + _i2c.write( FXOS8700CQ_SLAVE_ADDR, data, 2); + + // write 0000 1101 = 0x0D to accelerometer control register 1 + // [7-6]: aslp_rate=00 + // [5-3]: dr=011 for 50Hz data rate (when in hybrid mode) + // [2]: lnoise=1 for low noise mode + // [1]: f_read=0 for normal 16 bit reads + // [0]: active=1 to take the part out of standby and enable sampling + data[0] = FXOS8700CQ_CTRL_REG1; + data[1] = 0x19;//0x1D; + _i2c.write( FXOS8700CQ_SLAVE_ADDR, data, 2); +} + +void FXOS8700Q::ReadXYZ(float * a, float * m) +{ + char d[13]; + int16_t t[6]; + + RegRead( FXOS8700CQ_STATUS, d, 13); + t[0] = ((d[1] * 256) + ((unsigned short) d[2])); + t[1] = ((d[3] * 256) + ((unsigned short) d[4])); + t[2] = ((d[5] * 256) + ((unsigned short) d[6])); + t[3] = ((d[7] * 256) + ((unsigned short) d[8])); + t[4] = ((d[9] * 256) + ((unsigned short) d[10])); + t[5] = ((d[11] * 256) + ((unsigned short) d[12])); + + a[0] = (float) t[0] / 16384.0; + a[1] = (float) t[1] / 16384.0; + a[2] = (float) t[2] / 16384.0; + m[0] = (float) t[3] / 10.0; + m[1] = (float) t[4] / 10.0; + m[2] = (float) t[5] / 10.0; +} + \ No newline at end of file
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/FXOS8700Q.h Mon Apr 07 00:58:50 2014 +0000 @@ -0,0 +1,65 @@ +#ifndef FXOS8700Q_H +#define FXOS8700Q_H + +#include "mbed.h" +// FXOS8700CQ I2C address +#define FXOS8700CQ_SLAVE_ADDR 0x3C // with pins SA0=0, SA1=0 + +// FXOS8700CQ internal register addresses +#define FXOS8700CQ_STATUS 0x00 +#define FXOS8700CQ_WHOAMI 0x0D +#define FXOS8700CQ_XYZ_DATA_CFG 0x0E +#define FXOS8700CQ_CTRL_REG1 0x2A +#define FXOS8700CQ_M_CTRL_REG1 0x5B +#define FXOS8700CQ_M_CTRL_REG2 0x5C +#define FXOS8700CQ_WHOAMI_VAL 0xC7 + +class FXOS8700Q +{ +public: + /** + * MPL3115A2 constructor + * + * @param sda SDA pin + * @param sdl SCL pin + * @param addr addr of the I2C peripheral + */ + FXOS8700Q(PinName sda, PinName scl); + + /** + * Get the value of the WHO_AM_I register + * + * @returns DEVICE_ID value == ?? + */ + //uint8_t getDeviceID(); + + /** + * Return the STATUS register value + * + * @returns STATUS register value + */ + //unsigned char getStatus( void); + + /** + * Get the Accelerometer & Magnetometer values + * Accelerometer data is in G's + * MAgnetometer Data is in microteslas + * + * @returns altimeter value as float + */ + void ReadXYZ(float * a, float * m); + + +private: + + I2C _i2c; + /** Set the device in active mode + */ + void begin( void); + + void RegRead( char reg, char * d, int len); + + +}; + +#endif