Revision 2:4c2f8a3549a9, committed 2014-05-28

Comitter:

trm

Date:

Wed May 28 17:08:33 2014 +0000

Parent:

1:3ec7e2676e48

Child:

3:2ce85aa45d7d

Commit message:

Updates to correctness! Correctly fill accel/magn data structs. Access to accel sensor scale (2/4/8g). More comments and documentation. #define for many configuration register properties.

Changed in this revision

--- a/FXOS8700CQ.cpp	Wed May 28 13:40:59 2014 +0000
+++ b/FXOS8700CQ.cpp	Wed May 28 17:08:33 2014 +0000
@@ -11,29 +11,34 @@
     uint8_t data[6] = {0, 0, 0, 0, 0, 0}; // target device write address, single byte to write at address
 
     // TODO: verify WHOAMI?
-    
+
     // TODO: un-magic-number register configuration
 
     // Place peripheral in standby for configuration, resetting CTRL_REG1
     data[0] = FXOS8700CQ_CTRL_REG1;
-    // Keep data[1] as 0x00
+    data[1] = 0x00; // this will unset CTRL_REG1:active
     write_regs(data, 2);
 
     // Now that the device is in standby, configure registers
 
     // Setup for write-though for CTRL_REG series
     // Keep data[0] as FXOS8700CQ_CTRL_REG1
-    data[1] = 0x08; // 400 Hz single rate, 200 Hz hybrid mode
+    data[1] =
+        FXOS8700CQ_CTRL_REG1_ASLP_RATE2(1) | // 0b01 gives sleep rate of 12.5Hz
+        FXOS8700CQ_CTRL_REG1_DR3(1); // 0x001 gives ODR of 400Hz/200Hz hybrid
 
     // FXOS8700CQ_CTRL_REG2;
-    data[2] = 0x18; // set low power sleep sampling, no auto sleep, normal sampling
+    data[2] =
+        FXOS8700CQ_CTRL_REG2_SMODS2(3) | // 0b11 gives low power sleep oversampling mode
+        FXOS8700CQ_CTRL_REG2_MODS2(1); // 0b01 gives low noise, low power oversampling mode
 
     // No configuration changes from default 0x00 in CTRL_REG3
     // Interrupts will be active low
     data[3] = 0x00;
 
     // FXOS8700CQ_CTRL_REG4;
-    data[4] = 0x01; // enable data ready interrupt
+    data[4] =
+        FXOS8700CQ_CTRL_REG4_INT_EN_DRDY;
 
     // No configuration changes from default 0x00 in CTRL_REG5
     // Data ready interrupt will appear on INT2
@@ -42,24 +47,32 @@
     // Write to the 5 CTRL_REG registers
     write_regs(data, 6);
 
-    // No configuration changes from default 0x00 in XYZ_DATA_CFG
-    // No high pass filter and +/- 2g range for accelerometer
-    // Do not write any changes
+    // FXOS8700CQ_XYZ_DATA_CFG
+    data[0] = FXOS8700CQ_XYZ_DATA_CFG;
+    data[1] =
+        FXOS8700CQ_XYZ_DATA_CFG_FS2(1); // 0x01 gives 4g full range, 0.488mg/LSB
+    write_regs(data, 2);
 
     // Setup for write-through for M_CTRL_REG series
     data[0] = FXOS8700CQ_M_CTRL_REG1;
-    data[1] = 0x9F; // automatic calibration, maximum oversampling, hybrid sampling mode
+    data[1] =
+        FXOS8700CQ_M_CTRL_REG1_M_ACAL | // set automatic calibration
+        FXOS8700CQ_M_CTRL_REG1_MO_OS3(7) | // use maximum magnetic oversampling
+        FXOS8700CQ_M_CTRL_REG1_M_HMS2(3); // enable hybrid sampling (both sensors)
 
     // FXOS8700CQ_M_CTRL_REG2
-    data[2] = 0x20; // allow automatic read-through from accel to magn data at acc_z (0x05/0x06)
+    data[2] =
+        FXOS8700CQ_M_CTRL_REG2_HYB_AUTOINC_MODE;
 
     // FXOS8700CQ_M_CTRL_REG3
-    data[3] = 0x70; // use calibration data, sleep oversampling
+    data[3] =
+        FXOS8700CQ_M_CTRL_REG3_M_ASLP_OS3(7); // maximum sleep magnetic oversampling
 
     // Write to the 3 M_CTRL_REG registers
     write_regs(data, 4);
 
     // Peripheral is configured, but disabled
+    enabled = false;
 }
 
 // Destruct class
@@ -70,18 +83,22 @@
 {
     uint8_t data[2];
     read_regs( FXOS8700CQ_CTRL_REG1, &data[1], 1);
-    data[1] |= 0x01; // set bit 0, CTRL_REG1:active
+    data[1] |= FXOS8700CQ_CTRL_REG1_ACTIVE;
     data[0] = FXOS8700CQ_CTRL_REG1;
     write_regs(data, 2); // write back
+
+    enabled = true;
 }
 
 void FXOS8700CQ::disable(void)
 {
     uint8_t data[2];
     read_regs( FXOS8700CQ_CTRL_REG1, &data[1], 1);
-    data[1] &= 0xFE; // unset bit 0, CTRL_REG1:active
     data[0] = FXOS8700CQ_CTRL_REG1;
+    data[1] &= ~FXOS8700CQ_CTRL_REG1_ACTIVE;
     write_regs(data, 2); // write back
+
+    enabled = false;
 }
 
 
@@ -98,22 +115,55 @@
     return databyte;
 }
 
-void FXOS8700CQ::get_data(SRAWDATA *accel_data, SRAWDATA *magn_data)
+uint8_t FXOS8700CQ::get_data(SRAWDATA *accel_data, SRAWDATA *magn_data)
 {
-    read_regs(FXOS8700CQ_OUT_X_MSB, raw, FXOS8700CQ_READ_LEN); // WRONG, getting accel then magn
+    if(!enabled) {
+        return 1;
+    }
+
+    read_regs(FXOS8700CQ_M_OUT_X_MSB, raw, FXOS8700CQ_READ_LEN);
 
     // Pull out 16-bit, 2's complement magnetometer data
     magn_data->x = (raw[0] << 8) | raw[1];
     magn_data->y = (raw[2] << 8) | raw[3];
     magn_data->z = (raw[4] << 8) | raw[5];
 
-    // Below is wrong, using left-justified version
     // Pull out 14-bit, 2's complement, right-justified accelerometer data
     accel_data->x = (raw[6] << 8) | raw[7];
     accel_data->y = (raw[8] << 8) | raw[9];
     accel_data->z = (raw[10] << 8) | raw[11];
+
+    // Have to apply corrections to make the int16_t correct
+    if(accel_data->x > UINT14_MAX/2) {
+        accel_data->x -= UINT14_MAX;
+    }
+    if(accel_data->y > UINT14_MAX/2) {
+        accel_data->y -= UINT14_MAX;
+    }
+    if(accel_data->z > UINT14_MAX/2) {
+        accel_data->z -= UINT14_MAX;
+    }
+
+    return 0;
 }
 
+uint8_t FXOS8700CQ::get_accel_scale(void)
+{
+    uint8_t data = 0x00;
+    read_regs(FXOS8700CQ_XYZ_DATA_CFG, &data, 1);
+    data &= FXOS8700CQ_XYZ_DATA_CFG_FS2(3); // mask with 0b11
+
+    switch(data) {
+        case FXOS8700CQ_XYZ_DATA_CFG_FS2(0):
+            return 2;
+        case FXOS8700CQ_XYZ_DATA_CFG_FS2(1):
+            return 4;
+        case FXOS8700CQ_XYZ_DATA_CFG_FS2(2):
+            return 8;
+        default:
+            return 0;
+    }
+}
 
 // Private methods
 

--- a/FXOS8700CQ.h	Wed May 28 13:40:59 2014 +0000
+++ b/FXOS8700CQ.h	Wed May 28 17:08:33 2014 +0000
@@ -15,19 +15,82 @@
 #define FXOS8700CQ_STATUS 0x00
 #define FXOS8700CQ_OUT_X_MSB 0x01
 #define FXOS8700CQ_WHOAMI 0x0D
+#define FXOS8700CQ_M_OUT_X_MSB 0x33
+
 #define FXOS8700CQ_XYZ_DATA_CFG 0x0E
+
 #define FXOS8700CQ_CTRL_REG1 0x2A
 #define FXOS8700CQ_CTRL_REG2 0x2B
 #define FXOS8700CQ_CTRL_REG3 0x2C
 #define FXOS8700CQ_CTRL_REG4 0x2D
 #define FXOS8700CQ_CTRL_REG5 0x2E
 
-#define FXOS8700CQ_M_OUT_X_MSB 0x34
-
 #define FXOS8700CQ_M_CTRL_REG1 0x5B
 #define FXOS8700CQ_M_CTRL_REG2 0x5C
 #define FXOS8700CQ_M_CTRL_REG3 0x5D
 
+// FXOS8700CQ configuration macros, per register
+
+#define FXOS8700CQ_CTRL_REG1_ASLP_RATE2(x) (x << 6) // x is 2-bit
+#define FXOS8700CQ_CTRL_REG1_DR3(x) (x << 3) // x is 3-bit
+#define FXOS8700CQ_CTRL_REG1_LNOISE (1 << 2)
+#define FXOS8700CQ_CTRL_REG1_F_READ (1 << 1)
+#define FXOS8700CQ_CTRL_REG1_ACTIVE (1 << 0)
+
+#define FXOS8700CQ_CTRL_REG2_ST (1 << 7)
+#define FXOS8700CQ_CTRL_REG2_RST (1 << 6)
+#define FXOS8700CQ_CTRL_REG2_SMODS2(x) (x << 3) // x is 2-bit
+#define FXOS8700CQ_CTRL_REG2_SLPE (1 << 2)
+#define FXOS8700CQ_CTRL_REG2_MODS2(x) (x << 0) // x is 2-bit
+
+#define FXOS8700CQ_CTRL_REG3_FIFO_GATE (1 << 7)
+#define FXOS8700CQ_CTRL_REG3_WAKE_TRANS (1 << 6)
+#define FXOS8700CQ_CTRL_REG3_WAKE_LNDPRT (1 << 5)
+#define FXOS8700CQ_CTRL_REG3_WAKE_PULSE (1 << 4)
+#define FXOS8700CQ_CTRL_REG3_WAKE_FFMT (1 << 3)
+#define FXOS8700CQ_CTRL_REG3_WAKE_A_VECM (1 << 2)
+#define FXOS8700CQ_CTRL_REG3_IPOL (1 << 1)
+#define FXOS8700CQ_CTRL_REG3_PP_OD (1 << 0)
+
+#define FXOS8700CQ_CTRL_REG4_INT_EN_ASLP (1 << 7)
+#define FXOS8700CQ_CTRL_REG4_INT_EN_FIFO (1 << 6)
+#define FXOS8700CQ_CTRL_REG4_INT_EN_TRANS (1 << 5)
+#define FXOS8700CQ_CTRL_REG4_INT_EN_LNDPRT (1 << 4)
+#define FXOS8700CQ_CTRL_REG4_INT_EN_PULSE (1 << 3)
+#define FXOS8700CQ_CTRL_REG4_INT_EN_FFMT (1 << 2)
+#define FXOS8700CQ_CTRL_REG4_INT_EN_A_VECM (1 << 1)
+#define FXOS8700CQ_CTRL_REG4_INT_EN_DRDY (1 << 0)
+
+#define FXOS8700CQ_CTRL_REG5_INT_CFG_ASLP (1 << 7)
+#define FXOS8700CQ_CTRL_REG5_INT_CFG_FIFO (1 << 6)
+#define FXOS8700CQ_CTRL_REG5_INT_CFG_TRANS (1 << 5)
+#define FXOS8700CQ_CTRL_REG5_INT_CFG_LNDPRT (1 << 4)
+#define FXOS8700CQ_CTRL_REG5_INT_CFG_PULSE (1 << 3)
+#define FXOS8700CQ_CTRL_REG5_INT_CFG_FFMT (1 << 2)
+#define FXOS8700CQ_CTRL_REG5_INT_CFG_A_VECM (1 << 1)
+#define FXOS8700CQ_CTRL_REG5_INT_CFG_DRDY (1 << 0)
+
+#define FXOS8700CQ_XYZ_DATA_CFG_HPF_OUT (1 << 4)
+#define FXOS8700CQ_XYZ_DATA_CFG_FS2(x) (x << 0) // x is 2-bit
+
+#define FXOS8700CQ_M_CTRL_REG1_M_ACAL (1 << 7)
+#define FXOS8700CQ_M_CTRL_REG1_M_RST (1 << 6)
+#define FXOS8700CQ_M_CTRL_REG1_M_OST (1 << 5)
+#define FXOS8700CQ_M_CTRL_REG1_MO_OS3(x) (x << 2) // x is 3-bit
+#define FXOS8700CQ_M_CTRL_REG1_M_HMS2(x) (x << 0) // x is 2-bit
+
+#define FXOS8700CQ_M_CTRL_REG2_HYB_AUTOINC_MODE (1 << 5)
+#define FXOS8700CQ_M_CTRL_REG2_M_MAXMIN_DIS (1 << 4)
+#define FXOS8700CQ_M_CTRL_REG2_M_MAXMIN_DIS_THS (1 << 3)
+#define FXOS8700CQ_M_CTRL_REG2_M_MAXMIN_RST (1 << 2)
+#define FXOS8700CQ_M_CTRL_REG2_M_RST_CNT2(x) (x << 0) // x is 2-bit
+
+#define FXOS8700CQ_M_CTRL_REG3_M_RAW (1 << 7)
+#define FXOS8700CQ_M_CTRL_REG3_M_ASLP_OS3(x) (x << 4) // x is 3-bit
+#define FXOS8700CQ_M_CTRL_REG3_M_THS_XYZ_UPDATE (1 << 3)
+#define FXOS8700CQ_M_CTRL_REG3_M_ST_Z (1 << 2)
+#define FXOS8700CQ_M_CTRL_REG3_M_ST_XY2(x) (x << 0) // x is 2-bit
+
 // FXOS8700CQ WHOAMI production register value
 #define FXOS8700CQ_WHOAMI_VAL 0xC7
 
@@ -65,13 +128,12 @@
     * @param sdl SCL pin
     * @param addr address of the I2C peripheral in (7-bit << 1) form
     */
-
     FXOS8700CQ(PinName sda, PinName scl, int addr);
 
     /**
     * FXOS8700CQ destructor
     */
-    ~FXOS8700CQ();
+    ~FXOS8700CQ(void);
 
     void enable(void);
     void disable(void);
@@ -83,14 +145,23 @@
     *
     * @param accel_data destination XYZ accelerometer data struct
     * @param magn_data destination XYZ magnetometer data struct
+    * @return 0 on success, non-zero on failure
     */
-    void get_data(SRAWDATA *accel_data, SRAWDATA *magn_data);
+    uint8_t get_data(SRAWDATA *accel_data, SRAWDATA *magn_data);
+    
+    /**
+    * Retrieve the full-range scale value of the accelerometer
+    * 
+    * @return 2, 4, or 8, depending on part configuration; 0 on error
+    */
+    uint8_t get_accel_scale(void);
 
 
 
 private:
     I2C dev_i2c; // instance of the mbed I2C class
     uint8_t dev_addr; // Device I2C address, in (7-bit << 1) form
+    bool enabled;
 
     // I2C helper methods
     void read_regs(int reg_addr, uint8_t* data, int len);