ak7451.h

00001 #ifndef AK7451_H
00002 #define AK7451_H
00003 
00004 #include "mbed.h"
00005 
00006 /**
00007  * This is a device driver of AK7451 with SPI interface.
00008  *
00009  * @note AK7451 is a high speed angle sensor IC manufactured by AKM.
00010  * 
00011  * Example:
00012  * @code
00013  * #include "mbed.h"
00014  * #include "ak7451.h"
00015  * 
00016  * 
00017  * int main() {
00018  *     // Creates an instance of SPI
00019  * }
00020  * @endcode
00021  */
00022 class AK7451
00023 {
00024 public:
00025 
00026     /**
00027      * Available opration modes in AK7451.
00028      */
00029     typedef enum {
00030         AK7451_NORMAL_MODE  = 0x0000,   /**< Normal mode operation. */
00031         AK7451_USER_MODE    = 0x050F,   /**< User mode operation. */
00032     } OperationMode;
00033 
00034     /**
00035      * Status of function. 
00036      */
00037     typedef enum {
00038         SUCCESS,                    /**< The function processed successfully. */
00039         ERROR,                      /**< General Error */
00040         ERROR_IN_USER_MODE,         /**< Error in user mode. */
00041         ERROR_IN_NORMAL_MODE,       /**< Error in normal mode. */
00042         ERROR_PARITY,               /**< Parity bit error. */
00043         ERROR_ABNORMAL_STRENGTH,    /**< Abnormal strength error. */
00044     } Status;
00045 
00046     /**
00047      * Constructor.
00048      *
00049      */
00050     AK7451();
00051 
00052     /**
00053      * Destructor.
00054      *
00055      */
00056      ~AK7451();
00057 
00058     /**
00059      * begin
00060      *
00061      * @param *spi pointer to SPI instance
00062      * @param *cs pointer to DigitalOut instance for CS
00063      */
00064     void begin(SPI *spi, DigitalOut *cs);
00065     
00066     /**
00067      * Check the connection. 
00068      *
00069      * @note Connection check is performed by reading a register which has a fixed value and verify it.
00070      *
00071      * @return Returns SUCCESS when succeeded, otherwise returns another code.
00072      */
00073     Status checkConnection();
00074 
00075     /** 
00076      * Writes data to EEPROM on the device. 
00077      * @param address EEPROM address
00078      * @param data data to be written
00079      * @return Returns SUCCESS when succeeded, otherwise returns another.
00080      */
00081     Status writeEEPROM(char address, const char *data);
00082 
00083     /** 
00084      *  Reads data from EEPROM on the device. 
00085      * @param address EEPROM address
00086      * @param data data to read
00087      * @return Returns SUCCESS when succeeded, otherwise returns another.
00088      */
00089     Status readEEPROM(char address, char *data);
00090 
00091     /** 
00092      * Writes data to register on the device. 
00093      * @param address register address
00094      * @param data data to be written
00095      * @return Returns SUCCESS when succeeded, otherwise returns another.
00096      */
00097     Status writeRegister(char address, const char *data);
00098 
00099     /** 
00100      *  Reads data from register on the device. 
00101      * @param address register address
00102      * @param data data to read
00103      * @return Returns SUCCESS when succeeded, otherwise returns another.
00104      */
00105     Status readRegister(char address, char *data);
00106 
00107     /**
00108      * Sets device operation mode.
00109      *
00110      * @param mode device opration mode
00111      *
00112      * @return Returns SUCCESS when succeeded, otherwise returns another code.
00113      */
00114     Status setOperationMode(OperationMode mode);
00115 
00116     /**
00117      * Gets device operation mode.
00118      *
00119      * @return Returns OperationMode.
00120      */
00121     OperationMode getOperationMode();
00122 
00123     /**
00124      * Reads angle data from the device.
00125      *
00126      * @param angle pointer to read angle data buffer
00127      *
00128      * @return Returns SUCCESS when succeeded, otherwise returns another code.
00129      */
00130     Status readAngle(char *angle);
00131     
00132     /**
00133      * Measures and reads angle, magnetic flux density and abnormal state code while in the user mode.
00134      *
00135      * @param angle pointer to angle data buffer
00136      * @param density magnetic flux density
00137      * @param abnormal_state abnormal state
00138      *
00139      * @return Returns SUCCESS when succeeded, otherwise returns another code.
00140      */
00141     Status readAngleMeasureCommand(char *angle, char *density, char *abnormal_state);
00142     
00143     /**
00144      * Measures current angle and sets the value to EEPROM as zero angle position.
00145      *
00146      * @return Returns SUCCESS when succeeded, otherwise returns another code.
00147      */
00148     Status setAngleZero();
00149     
00150     /**
00151      * Sets the value to EEPROM as zero angle position.
00152      *
00153      * @param angle zero angle position
00154      *
00155      * @return Returns SUCCESS when succeeded, otherwise returns another code.
00156      */
00157     Status setAngleZero(const char *angle);
00158 
00159 private:        
00160     /**
00161      * Holds a pointer to an SPI object. 
00162      */
00163     SPI *_spi;
00164 
00165     /**
00166      * Holds a DigitalOut oblject for CS; 
00167      */
00168     DigitalOut *_cs;
00169     
00170     /**
00171      * Holds current mode 
00172      */
00173     OperationMode operationMode;
00174 
00175     /** 
00176      *  Reads data from device. 
00177      * @param operation_code OPCODE 
00178      * @param address memory/register addredd
00179      * @param *data pointer to the read buffer. length=2 fixed.
00180      * @return Returns SUCCESS when succeeded, otherwise returns another.
00181      */
00182     Status read(char operation_code, char address, char *data);
00183 
00184     /** 
00185      * Writes data to the device. 
00186      * @param operation_code OPCODE 
00187      * @param address memory/register addredd
00188      * @param *data pointer to the read buffer. length=2 fixed.
00189      * @return Returns SUCCESS when succeeded, otherwise returns another.
00190      */
00191     Status write(char operation_code, char address, const char *data);
00192 
00193     /** 
00194      * Checks parity bits sub function
00195      * @param data data 12bit read data
00196      * @param parity parity bit status
00197      * @param error error bit status
00198      * @return Returns SUCCESS when succeeded, otherwise returns another.
00199      */
00200     Status parityCheckSub(const char data, const char parity, const char error);
00201 
00202     /** 
00203      * Checks parity bits
00204      * @param data 2 byte read data to chek parity
00205      * @return Returns SUCCESS when succeeded, otherwise returns another.
00206      */
00207     Status parityCheck(const char *data);
00208 };
00209 
00210 #endif