Diff: ak8963.cpp

Revision:

0:fc56973c077a

Child:

1:a362b9e3aac2

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ak8963.cpp	Wed Aug 05 23:08:02 2015 +0000
@@ -0,0 +1,222 @@
+#include "ak8963.h"
+
+// REGISTER MAP
+#define AK8963_REG_WIA             0x00
+#define AK8963_REG_INFO            0x01
+#define AK8963_REG_ST1             0x02
+#define AK8963_REG_HXL             0x03
+#define AK8963_REG_HXH             0x04
+#define AK8963_REG_HYL             0x05
+#define AK8963_REG_HYH             0x06
+#define AK8963_REG_HZL             0x07
+#define AK8963_REG_HZH             0x08
+#define AK8963_REG_ST2             0x09
+#define AK8963_REG_CNTL1           0x0A
+#define AK8963_REG_CNTL2           0x0B
+#define AK8963_REG_ASTC            0x0C
+#define AK8963_REG_TS1             0x0D
+#define AK8963_REG_TS2             0x0E
+#define AK8963_REG_I2CDIS          0x0F
+#define AK8963_REG_ASAX            0x10
+#define AK8963_REG_ASAY            0x11
+#define AK8963_REG_ASAZ            0x12
+#define AK8963_REG_RSV             0x13
+
+// BITS in CNTL1 register
+#define AK8963_CNTL1_MODE_PDN       0x00     // POWER DOWN MODE
+#define AK8963_CNTL1_MODE_SNG       0x01     // SINGLE MEASUREMENT MODE
+#define AK8963_CNTL1_MODE_CNT1      0x02     // CONTINUOUS MEASUREMENT MODE 1
+#define AK8963_CNTL1_MODE_CNT2      0x06     // CONTINUOUS MEASUREMENT MODE 2
+#define AK8963_CNTL1_MODE_EXT       0x04     // EXTERNAL TRIGGER MEASUREMENT MODE
+#define AK8963_CNTL1_MODE_TEST      0x08     // SELF-TEST MODE
+#define AK8963_CNTL1_MODE_FUSE_ROM  0x0F     // FUSE ROM ACCESS MODE
+#define AK8963_CNTL1_OUTPUT_14BIT   0x00
+#define AK8963_CNTL1_OUTPUT_16BIT   0x10
+
+#define AK8963_BIT_MASK_DRDY        0x01
+
+#define AK8963_REG_WIA_VAL          0x48
+
+#define AK8963_BUF_LENGTH_ASA          3
+#define AK8963_BUF_LENGTH_BDATA        8
+#define AK8963_WAIT_MODE_TRANSITION  100
+#define AK8963_DEFAULT_OUTPUT_BIT   AK8963_CNTL1_OUTPUT_16BIT
+#define AK8963_SENSITIVITY          (0.15)   // uT/LSB
+
+#define AK8963_WAIT_POWER_DOWN_US    200
+
+#define LEN_ONE_BYTE  1
+
+AK8963::AK8963(I2C *conn, SlaveAddress addr) {
+    slaveAddress = addr;
+    connection = conn;
+    getSensitivityAdjustment(&sensitivityAdjustment);
+}
+
+AK8963::Status AK8963::checkConnection() {
+    AK8963::Status status = AK8963::SUCCESS;
+    
+    // Gets the WIA register value.
+    char wiaValue = 0;
+    if ((status=AK8963::read(AK8963_REG_WIA, &wiaValue, LEN_ONE_BYTE)) != SUCCESS) {
+        return status;
+    }
+
+    // Checks the obtained value equals to the supposed value.
+    if (wiaValue != AK8963_REG_WIA_VAL) {
+        return AK8963::ERROR;
+    }
+    
+    return status;
+}
+
+AK8963::Status AK8963::read(char registerAddress, char *buf, int length) {
+    // Writes a start address
+    if (connection->write((slaveAddress << 1), &registerAddress, LEN_ONE_BYTE) != 0) {
+        // I2C write failed.
+        return AK8963::ERROR_I2C_WRITE;
+    }
+    
+    // Reads register data
+    if (connection->read((slaveAddress << 1), buf, length) != 0) {
+        // I2C read failed.
+        return AK8963::ERROR_I2C_READ;
+    }
+    
+    return AK8963::SUCCESS;
+}
+
+AK8963::Status AK8963::write(char registerAddress, const char *buf, int length) {
+    int bufLength = length + 1;
+    char data[bufLength];
+
+    // Creates data to be sent.
+    data[0] = registerAddress;    
+    for (int i=0; i < length; i++) {
+        data[1+i] = buf[i];
+    }
+    
+    // Writes a start address. Doesn't send a stop condition.
+    if (connection->write((slaveAddress << 1), data, bufLength) != 0) {
+        // I2C write failed.
+        return AK8963::ERROR_I2C_WRITE;
+    }
+
+    return AK8963::SUCCESS;
+}
+
+AK8963::Status AK8963::isDataReady() {
+    AK8963::Status status = AK8963::ERROR;
+    
+    // Gets the ST1 register value.
+    char st1Value = 0;
+    if ((status=AK8963::read(AK8963_REG_ST1, &st1Value, LEN_ONE_BYTE)) != AK8963::SUCCESS) {
+        // I2C read failed.
+        return status;
+    }
+
+    // Sets a return status corresponds to the obtained value.    
+    if ((st1Value & AK8963_BIT_MASK_DRDY) > 0) {
+        status = AK8963::DATA_READY;
+    } else {
+        status = AK8963::NOT_DATA_READY;
+    }
+    
+    return status;
+}
+
+AK8963::Status AK8963::getData(char *buf) {
+    AK8963::Status status = AK8963::ERROR;
+    
+    if ((status=AK8963::read(AK8963_REG_ST1, buf, AK8963_BUF_LENGTH_BDATA)) != AK8963::SUCCESS) {
+        // I2C read failed.
+        return status;
+    }
+    
+    return status;
+}
+
+AK8963::Status AK8963::setOperationMode(AK8963::OperationMode mode) {
+    AK8963::Status status = AK8963::ERROR;
+    
+    // The device has to be put into power-down mode first before switching mode.
+    char buf = (char)AK8963::MODE_POWER_DOWN;
+    if (mode != AK8963::MODE_POWER_DOWN) {
+        if ((status=AK8963::write(AK8963_REG_CNTL1, &buf, LEN_ONE_BYTE)) != AK8963::SUCCESS) {
+            // I2C write failed.
+            return status;
+        }
+        wait_us(AK8963_WAIT_POWER_DOWN_US);
+    }
+
+
+    // Switch to the specified mode.
+    buf = (char)(mode | AK8963_CNTL1_OUTPUT_16BIT);    
+    if ((status=AK8963::write(AK8963_REG_CNTL1, &buf, LEN_ONE_BYTE)) != AK8963::SUCCESS) {
+        // I2C write failed.
+        return status;
+    }
+    
+    wait_us(AK8963_WAIT_POWER_DOWN_US);
+    
+    return AK8963::SUCCESS;
+}
+
+AK8963::Status AK8963::getMagneticVector(MagneticVector *vec) {
+    AK8963::Status status = AK8963::ERROR;
+    char buf[AK8963_BUF_LENGTH_BDATA];
+    
+    if ((status=AK8963::getData(buf)) != AK8963::SUCCESS) {
+        // Failed to get data.
+        return status;
+    }
+    
+    int16_t xi = (int16_t)((buf[2] << 8) | buf[1]);
+    int16_t yi = (int16_t)((buf[4] << 8) | buf[3]);
+    int16_t zi = (int16_t)((buf[6] << 8) | buf[5]);
+    
+    vec->mx = (float)(xi * ((sensitivityAdjustment.x + 128)/256.0));
+    vec->my = (float)(yi * ((sensitivityAdjustment.y + 128)/256.0));
+    vec->mz = (float)(zi * ((sensitivityAdjustment.z + 128)/256.0));
+    
+    return AK8963::SUCCESS;
+}
+
+
+AK8963::Status AK8963::getSensitivityAdjustment(SensitivityAdjustment *sns) {
+    AK8963::Status status = AK8963::ERROR;
+    
+    // Set the device into the fuse ROM access mode.
+    char data = AK8963_CNTL1_MODE_FUSE_ROM;
+    if ((status=AK8963::write(AK8963_REG_CNTL1, &data, LEN_ONE_BYTE)) != AK8963::SUCCESS) {
+        // I2C write failed.
+        return status;
+    }
+    
+    // Wait
+    wait_us(AK8963_WAIT_POWER_DOWN_US);
+    
+    // Read the fuse ROM
+    char buf[AK8963_BUF_LENGTH_ASA];
+    if ((status=AK8963::read(AK8963_REG_ASAX, buf, AK8963_BUF_LENGTH_ASA)) != AK8963::SUCCESS) {
+        // I2C read failed.
+        return status;
+    }
+    
+    sns->x = buf[0];
+    sns->y = buf[1];
+    sns->z = buf[2];
+    
+    // Set the device into the power-down mode
+    data = AK8963_CNTL1_MODE_PDN;
+    if ((status=AK8963::write(AK8963_REG_CNTL1, &data, LEN_ONE_BYTE)) != AK8963::SUCCESS) {
+        // I2C write failed.
+        return status;
+    }
+    
+    // Wait
+    wait_us(AK8963_WAIT_POWER_DOWN_US);
+    
+    return AK8963::SUCCESS;  
+}
+