Robert Bolling / FXOS8700CQ

minor changes to support mobile life IoT project

Fork of FXOS8700CQ by Thomas Murphy

FXOS8700CQ.cpp@0:cf6299acfe98, 2014-05-28 (annotated)

Committer:
trm
Date:
Wed May 28 13:28:18 2014 +0000
Revision:
0:cf6299acfe98
Child:
2:4c2f8a3549a9
Successful driver for FXOS8700CQ on FRDM-K64F. Configured for 2g accelerometer range, hybrid readings at 200Hz, data ready interrupts on INT2, auto-zero of the magnometer, full-data read. WARNING: data is swapped acc/magn and acc data is 4x large.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
trm 0:cf6299acfe98 1 #include "FXOS8700CQ.h"
trm 0:cf6299acfe98 2
trm 0:cf6299acfe98 3 uint8_t status_reg; // Status register contents
trm 0:cf6299acfe98 4 uint8_t raw[FXOS8700CQ_READ_LEN]; // Buffer for reading out stored data
trm 0:cf6299acfe98 5
trm 0:cf6299acfe98 6 // Construct class and its contents
trm 0:cf6299acfe98 7 FXOS8700CQ::FXOS8700CQ(PinName sda, PinName scl, int addr) : dev_i2c(sda, scl), dev_addr(addr)
trm 0:cf6299acfe98 8 {
trm 0:cf6299acfe98 9 // Initialization of the FXOS8700CQ
trm 0:cf6299acfe98 10 dev_i2c.frequency(I2C_400K); // Use maximum I2C frequency
trm 0:cf6299acfe98 11 uint8_t data[6] = {0, 0, 0, 0, 0, 0}; // target device write address, single byte to write at address
trm 0:cf6299acfe98 12
trm 0:cf6299acfe98 13 // TODO: verify WHOAMI?
trm 0:cf6299acfe98 14
trm 0:cf6299acfe98 15 // TODO: un-magic-number register configuration
trm 0:cf6299acfe98 16
trm 0:cf6299acfe98 17 // Place peripheral in standby for configuration, resetting CTRL_REG1
trm 0:cf6299acfe98 18 data[0] = FXOS8700CQ_CTRL_REG1;
trm 0:cf6299acfe98 19 // Keep data[1] as 0x00
trm 0:cf6299acfe98 20 write_regs(data, 2);
trm 0:cf6299acfe98 21
trm 0:cf6299acfe98 22 // Now that the device is in standby, configure registers
trm 0:cf6299acfe98 23
trm 0:cf6299acfe98 24 // Setup for write-though for CTRL_REG series
trm 0:cf6299acfe98 25 // Keep data[0] as FXOS8700CQ_CTRL_REG1
trm 0:cf6299acfe98 26 data[1] = 0x08; // 400 Hz single rate, 200 Hz hybrid mode
trm 0:cf6299acfe98 27
trm 0:cf6299acfe98 28 // FXOS8700CQ_CTRL_REG2;
trm 0:cf6299acfe98 29 data[2] = 0x18; // set low power sleep sampling, no auto sleep, normal sampling
trm 0:cf6299acfe98 30
trm 0:cf6299acfe98 31 // No configuration changes from default 0x00 in CTRL_REG3
trm 0:cf6299acfe98 32 // Interrupts will be active low
trm 0:cf6299acfe98 33 data[3] = 0x00;
trm 0:cf6299acfe98 34
trm 0:cf6299acfe98 35 // FXOS8700CQ_CTRL_REG4;
trm 0:cf6299acfe98 36 data[4] = 0x01; // enable data ready interrupt
trm 0:cf6299acfe98 37
trm 0:cf6299acfe98 38 // No configuration changes from default 0x00 in CTRL_REG5
trm 0:cf6299acfe98 39 // Data ready interrupt will appear on INT2
trm 0:cf6299acfe98 40 data[5] = 0x00;
trm 0:cf6299acfe98 41
trm 0:cf6299acfe98 42 // Write to the 5 CTRL_REG registers
trm 0:cf6299acfe98 43 write_regs(data, 6);
trm 0:cf6299acfe98 44
trm 0:cf6299acfe98 45 // No configuration changes from default 0x00 in XYZ_DATA_CFG
trm 0:cf6299acfe98 46 // No high pass filter and +/- 2g range for accelerometer
trm 0:cf6299acfe98 47 // Do not write any changes
trm 0:cf6299acfe98 48
trm 0:cf6299acfe98 49 // Setup for write-through for M_CTRL_REG series
trm 0:cf6299acfe98 50 data[0] = FXOS8700CQ_M_CTRL_REG1;
trm 0:cf6299acfe98 51 data[1] = 0x9F; // automatic calibration, maximum oversampling, hybrid sampling mode
trm 0:cf6299acfe98 52
trm 0:cf6299acfe98 53 // FXOS8700CQ_M_CTRL_REG2
trm 0:cf6299acfe98 54 data[2] = 0x20; // allow automatic read-through from accel to magn data at acc_z (0x05/0x06)
trm 0:cf6299acfe98 55
trm 0:cf6299acfe98 56 // FXOS8700CQ_M_CTRL_REG3
trm 0:cf6299acfe98 57 data[3] = 0x70; // use calibration data, sleep oversampling
trm 0:cf6299acfe98 58
trm 0:cf6299acfe98 59 // Write to the 3 M_CTRL_REG registers
trm 0:cf6299acfe98 60 write_regs(data, 4);
trm 0:cf6299acfe98 61
trm 0:cf6299acfe98 62 // Peripheral is configured, but disabled
trm 0:cf6299acfe98 63 }
trm 0:cf6299acfe98 64
trm 0:cf6299acfe98 65 // Destruct class
trm 0:cf6299acfe98 66 FXOS8700CQ::~FXOS8700CQ(void) {}
trm 0:cf6299acfe98 67
trm 0:cf6299acfe98 68
trm 0:cf6299acfe98 69 void FXOS8700CQ::enable(void)
trm 0:cf6299acfe98 70 {
trm 0:cf6299acfe98 71 uint8_t data[2];
trm 0:cf6299acfe98 72 read_regs( FXOS8700CQ_CTRL_REG1, &data[1], 1);
trm 0:cf6299acfe98 73 data[1] |= 0x01; // set bit 0, CTRL_REG1:active
trm 0:cf6299acfe98 74 data[0] = FXOS8700CQ_CTRL_REG1;
trm 0:cf6299acfe98 75 write_regs(data, 2); // write back
trm 0:cf6299acfe98 76 }
trm 0:cf6299acfe98 77
trm 0:cf6299acfe98 78 void FXOS8700CQ::disable(void)
trm 0:cf6299acfe98 79 {
trm 0:cf6299acfe98 80 uint8_t data[2];
trm 0:cf6299acfe98 81 read_regs( FXOS8700CQ_CTRL_REG1, &data[1], 1);
trm 0:cf6299acfe98 82 data[1] &= 0xFE; // unset bit 0, CTRL_REG1:active
trm 0:cf6299acfe98 83 data[0] = FXOS8700CQ_CTRL_REG1;
trm 0:cf6299acfe98 84 write_regs(data, 2); // write back
trm 0:cf6299acfe98 85 }
trm 0:cf6299acfe98 86
trm 0:cf6299acfe98 87
trm 0:cf6299acfe98 88 uint8_t FXOS8700CQ::status(void)
trm 0:cf6299acfe98 89 {
trm 0:cf6299acfe98 90 read_regs(FXOS8700CQ_STATUS, &status_reg, 1);
trm 0:cf6299acfe98 91 return status_reg;
trm 0:cf6299acfe98 92 }
trm 0:cf6299acfe98 93
trm 0:cf6299acfe98 94 uint8_t FXOS8700CQ::get_whoami(void)
trm 0:cf6299acfe98 95 {
trm 0:cf6299acfe98 96 uint8_t databyte = 0x00;
trm 0:cf6299acfe98 97 read_regs(FXOS8700CQ_WHOAMI, &databyte, 1);
trm 0:cf6299acfe98 98 return databyte;
trm 0:cf6299acfe98 99 }
trm 0:cf6299acfe98 100
trm 0:cf6299acfe98 101 void FXOS8700CQ::get_data(SRAWDATA *accel_data, SRAWDATA *magn_data)
trm 0:cf6299acfe98 102 {
trm 0:cf6299acfe98 103 read_regs(FXOS8700CQ_OUT_X_MSB, raw, FXOS8700CQ_READ_LEN); // WRONG, getting accel then magn
trm 0:cf6299acfe98 104
trm 0:cf6299acfe98 105 // Pull out 16-bit, 2's complement magnetometer data
trm 0:cf6299acfe98 106 magn_data->x = (raw[0] << 8) | raw[1];
trm 0:cf6299acfe98 107 magn_data->y = (raw[2] << 8) | raw[3];
trm 0:cf6299acfe98 108 magn_data->z = (raw[4] << 8) | raw[5];
trm 0:cf6299acfe98 109
trm 0:cf6299acfe98 110 // Below is wrong, using left-justified version
trm 0:cf6299acfe98 111 // Pull out 14-bit, 2's complement, right-justified accelerometer data
trm 0:cf6299acfe98 112 accel_data->x = (raw[6] << 8) | raw[7];
trm 0:cf6299acfe98 113 accel_data->y = (raw[8] << 8) | raw[9];
trm 0:cf6299acfe98 114 accel_data->z = (raw[10] << 8) | raw[11];
trm 0:cf6299acfe98 115 }
trm 0:cf6299acfe98 116
trm 0:cf6299acfe98 117
trm 0:cf6299acfe98 118 // Private methods
trm 0:cf6299acfe98 119
trm 0:cf6299acfe98 120 void FXOS8700CQ::read_regs(int reg_addr, uint8_t* data, int len)
trm 0:cf6299acfe98 121 {
trm 0:cf6299acfe98 122 char t[1] = {reg_addr};
trm 0:cf6299acfe98 123 dev_i2c.write(dev_addr, t, 1, true);
trm 0:cf6299acfe98 124 dev_i2c.read(dev_addr, (char *)data, len);
trm 0:cf6299acfe98 125 }
trm 0:cf6299acfe98 126
trm 0:cf6299acfe98 127 void FXOS8700CQ::write_regs(uint8_t* data, int len)
trm 0:cf6299acfe98 128 {
trm 0:cf6299acfe98 129 dev_i2c.write(dev_addr, (char*)data, len);
trm 0:cf6299acfe98 130 }