Diff: FXAS21000.cpp

Revision:

4:41bd7f360406

Parent:

2:cd21ef326977

--- a/FXAS21000.cpp	Mon Jun 02 17:36:38 2014 +0000
+++ b/FXAS21000.cpp	Wed Jul 08 13:34:46 2015 +0000
@@ -1,71 +1,185 @@
- #include "FXAS21000.h"
- 
-FXAS21000::FXAS21000(PinName sda, PinName scl) : _i2c(sda, scl) {
- 
-    begin();
-}
-              
-void FXAS21000::RegRead( char reg, char * d, int len)
+#include "FXAS21000.h"
+
+const uint16_t uint14_max = 0x3FFF;
+void static inline normalize_14bits(int16_t &x)
 {
-    char cmd[1];
-    cmd[0] = reg;
-char i2c_addr = FXAS21000_SLAVE_ADDR;
-_i2c.write( i2c_addr, cmd, 1, true);
-_i2c.read ( i2c_addr, d, len);
+    x = ((x) > (uint14_max/2)) ? (x - uint14_max) : (x);
 }
 
-void FXAS21000::begin(void)
+static int16_t dummy_int16_t = 0;
+static float dummy_float = 0.0f;
+
+FXAS21000::FXAS21000(I2C &i2c, uint8_t addr)
 {
-    char data[2];
-    // write 0000 1000 = 0x08 to gyro control register 1 to place FXAS21000 into
-    // standby
-    // [7-1] = 0000 000
-    // [0]: active=0
+    _i2c = &i2c;
+    _addr = addr;
+    // activate the peripheral
+    uint8_t data[2];
+    _i2c->frequency(400000);
+    
+    /*
+     * | ZR_COND | RST | ST | DR[2:0] | Active | Ready |
+     * |    0    |  0  | 0  |   010   |   0    |   0   |
+     * ZR_COND - Offset compensation calibration
+     * RST - Reset of the device
+     * DR - Sampling rate 50Hz (010)
+     * Active - Device is measuring
+     * Ready - Device is ready to measure but not taking samples
+     */
     data[0] = FXAS21000_CTRL_REG1;
-    data[1] = 0x08;
-    _i2c.write( FXAS21000_SLAVE_ADDR, data, 2);
+    data[1] = 0x08; // 00001000
+    writeRegs(data, 2);
     
-    // write 0001 1011 to CRTL_REG0 register
+    /*
+     * CTRL_REG0 can be only modified in Standby or Read modes
+     * | 0 | 0 | SPIW | SEL[1:0] | HPF_EN | FS[1:0] |
+     * | 0 | 0 |  0   |    11    |   0    |    11   |
+     * SPIW - SPI bus mode, zero for four wires
+     * SEL - High pass filter frequency cut-off
+     * HPF_EN - Enable high-pass filter
+     * FS - Full scale ranges +-1600 dps when 00
+     */
     data[0] = FXAS21000_CTRL_REG0;
     data[1] = 0x1B;
-    _i2c.write( FXAS21000_SLAVE_ADDR, data, 2);
-
-    // write 0000 1001 to gyro control register 1
+    writeRegs(data, 2);
+    
+    /*
+     * Same a first write but Active bit gets enabled
+     */
     data[0] = FXAS21000_CTRL_REG1;
     data[1] = 0x0A;
-    _i2c.write( FXAS21000_SLAVE_ADDR, data, 2);
+    writeRegs(data, 2);
+}
+
+FXAS21000::~FXAS21000()
+{
+    _i2c = 0;
+    _addr = 0;
+}
+
+void FXAS21000::readRegs(uint8_t addr, uint8_t *data, uint32_t len) const
+{
+    uint8_t t[1] = {addr};
+    _i2c->write(_addr, (char *)t, sizeof(t), true);
+    _i2c->read(_addr, (char *)data, len);
+}
+
+uint8_t FXAS21000::whoAmI() const
+{
+    uint8_t who_am_i = 0;
+    readRegs(FXAS21000_WHOAMI, &who_am_i, sizeof(who_am_i));
+    return who_am_i;
+}
+
+void FXAS21000::writeRegs(uint8_t * data, uint32_t len) const
+{
+    _i2c->write(_addr, (char *)data, len);
 }
 
-char FXAS21000::getWhoAmI(void)
+int16_t FXAS21000::getSensorAxis(uint8_t addr) const
+{
+    uint8_t res[2];
+    readRegs(addr, res, sizeof(res));
+    return static_cast<int16_t>((res[0] << 8) | res[1]);
+}
+
+void FXAS21000::enable(void) const
+{
+    uint8_t data[2];
+    readRegs(FXAS21000_CTRL_REG1, &data[1], 1);
+    data[1] |= 0x0A; // 00000010 to turn on Active bit
+    data[0] = FXAS21000_CTRL_REG1;
+    writeRegs(data, sizeof(data));
+}
+
+void FXAS21000::disable(void) const
 {
-    char d;
-    RegRead( FXAS21000_WHOAMI, &d, 1);
-    return(d);
+    uint8_t data[2];
+    readRegs(FXAS21000_CTRL_REG1, &data[1], 1);
+    data[1] &= 0xFD; // 11111101 to turn off Active bit
+    data[0] = FXAS21000_CTRL_REG1;
+    writeRegs(data, sizeof(data));
+}
+
+uint32_t FXAS21000::dataReady(void) const
+{
+    uint8_t stat = 0;
+    readRegs(FXAS21000_STATUS, &stat, 1);
+    stat &= 0x88; // 10001000 to zero out other bits
+    if(stat == 0x88) { // If 7th and 4th bit are positive then return 1
+        stat = 1;
+    } else {
+        stat = 0;    // Otherwise no data ready, return 0
+    }
+    return (uint32_t)stat;
 }
 
-void FXAS21000::ReadXYZ(float * a)
+// OK
+uint32_t FXAS21000::sampleRate(uint32_t frequency) const
 {
-    char d[7];
-    int16_t t[6];
+    return(50); // for now sample rate is fixed at 50Hz
+}
+
+int16_t FXAS21000Gyroscpe::getX(int16_t &x = dummy_int16_t) const
+{
+    x = getSensorAxis(FXAS21000_OUT_X_MSB) >> 2;
+    normalize_14bits(x);
+    return x;
+}
 
-    RegRead( FXAS21000_STATUS, d, 7);
-    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]));
-    //printf("%X\r\n", (int) d[0]);
+int16_t FXAS21000Gyroscpe::getY(int16_t &y = dummy_int16_t) const
+{
+    y = getSensorAxis(FXAS21000_OUT_Y_MSB) >> 2;
+    normalize_14bits(y);
+    return y;
+}
 
-    a[0] = (float) t[0] * 0.003125;
-    a[1] = (float) t[1] * 0.003125;
-    a[2] = (float) t[2] * 0.003125;
-  
+int16_t FXAS21000Gyroscpe::getZ(int16_t &z = dummy_int16_t) const
+{
+    z = getSensorAxis(FXAS21000_OUT_Z_MSB) >> 2;
+    normalize_14bits(z);
+    return z;
+}
+
+float FXAS21000Gyroscpe::getX(float &x = dummy_float) const
+{
+    int16_t val = getSensorAxis(FXAS21000_OUT_X_MSB) >> 2;
+    normalize_14bits(val);
+    x = val / 4096.0f;
+    return x;
 }
 
-void FXAS21000::ReadXYZraw(int16_t * t)
+float FXAS21000Gyroscpe::getY(float &y = dummy_float) const
 {
-    char d[7];
+    int16_t val = getSensorAxis(FXAS21000_OUT_Y_MSB) >> 2;
+    normalize_14bits(val);
+    y = val / 4096.0f;
+    return y;
+}
+
+float FXAS21000Gyroscpe::getZ(float &z = dummy_float) const
+{
+    int16_t val = getSensorAxis(FXAS21000_OUT_Z_MSB) >> 2;
+    normalize_14bits(val);
+    z = val / 4096.0f;
+    return z;
+}
 
-    RegRead( FXAS21000_STATUS, d, 7);
-    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]));
-}
\ No newline at end of file
+void FXAS21000Gyroscpe::getAxis(motion_data_counts_t &xyz) const
+{
+    xyz.x = getSensorAxis(FXAS21000_OUT_X_MSB) >> 2;
+    xyz.y = getSensorAxis(FXAS21000_OUT_Y_MSB) >> 2;
+    xyz.z = getSensorAxis(FXAS21000_OUT_Z_MSB) >> 2;
+    normalize_14bits(xyz.x);
+    normalize_14bits(xyz.y);
+    normalize_14bits(xyz.z);
+}
+
+void FXAS21000Gyroscpe::getAxis(motion_data_units_t &xyz) const
+{
+    motion_data_counts_t _xyz;
+    FXAS21000Gyroscpe::getAxis(_xyz);
+    xyz.x = _xyz.x / 4096.0f;
+    xyz.y = _xyz.y / 4096.0f;
+    xyz.z = _xyz.z / 4096.0f;
+}