Freescale Semiconductor FRDM-FXS-MULTI 데이터 시트

Sensors

32

Freescale Semiconductor, Inc.

This function configures the FXOS8700CQ for 200-Hz hybrid mode meaning that both accelerometer and magnetometer data 
are provided at the 200-Hz rate.The code is self-explanatory and can be easily customized for different settings.

// function configures FXOS8700CQcombination accelerometer and magnetometer sensor

 static _mqx_int s_FXOS8700CQ_start(MQX_FILE_PTR aFP)

{

uint8_t databyte;

// read and check the FXOS8700CQ WHOAMI register

if (s_i2c_read_regs(aFP, FXOS8700CQ_SLAVE_ADDR, FXOS8700CQ_WHOAMI, &databyte, 

(uint8_t) 1) != 1)

{

return (I2C_ERROR);

}

if (databyte != FXOS8700CQ_WHOAMI_VAL)

{

return (I2C_ERROR);

}

// write 0000 0000 = 0x00 to accelerometer control register 1 to place FXOS8700CQ 

into

// standby

// [7-1] = 0000 000

// [0]: active=0

databyte = 0x00;

if (s_i2c_write_regs(aFP, FXOS8700CQ_SLAVE_ADDR, FXOS8700CQ_CTRL_REG1, &databyte, 

(uint8_t) 1) != 1)

{

return (I2C_ERROR);

}

// 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

databyte = 0x1F;

if (s_i2c_write_regs(aFP, FXOS8700CQ_SLAVE_ADDR, FXOS8700CQ_M_CTRL_REG1, 

&databyte, (uint8_t) 1) != 1)

{

return (I2C_ERROR);

}

// 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

databyte = 0x20;