I2CSensor.h

00001 /* I2CSensor.h
00002  * Tested with mbed board: FRDM-KL46Z
00003  * Author: Mark Gottscho
00004  * mgottscho@ucla.edu
00005  */
00006 
00007 #ifndef SENSOR_H
00008 #define SENSOR_H
00009 
00010 #include "mbed.h"
00011  
00012 /**
00013  * Base class from which digital sensors using I2C should be derived to simplify low-level communications with the device.
00014  */
00015 class I2CSensor {
00016     public:
00017         /**
00018          * @param sda I2C SDA pin ID
00019          * @param scl I2C SCL pin ID
00020          * @param i2c_addr I2C 8-bit address (LSB is actually don't care)
00021          */
00022         I2CSensor (PinName sda, PinName scl, int i2c_addr);
00023         
00024         /**
00025          */
00026         ~I2CSensor();
00027         
00028         /**
00029          * @returns I2C SDA pin ID
00030          */
00031         PinName getSDAPin ();
00032         
00033         /**
00034          * @returns I2C SCL pin ID
00035          */
00036         PinName getSCLPin ();
00037         
00038         /**
00039          * @returns Device I2C address (LSB always 0 in this case, it is don't care)
00040          */
00041         uint8_t getDeviceI2CAddress ();
00042         
00043         /**
00044          * Read an 8-bit register.
00045          * @param reg_addr the register in the device
00046          * @returns The raw value from the register specified by reg_addr.
00047          */
00048         uint8_t getRegister(const uint8_t reg_addr);
00049         
00050         /**
00051          * Read a 16-bit register.
00052          * @param reg_addr the register in the device
00053          * @returns The raw value from the register specified by reg_addr.
00054          */
00055         uint16_t getRegister16b(const uint8_t reg_addr);
00056         
00057         /**
00058          * Set an 8-bit register.
00059          * @param reg_addr the register in the device
00060          * @param data the byte to write to the register
00061          */
00062         void setRegister(const uint8_t reg_addr, const uint8_t data);
00063         
00064         /**
00065          * Set a 16-bit register.
00066          * @param reg_addr the register in the device
00067          * @param data the byte to write to the register
00068          */
00069         void setRegister16b(const uint8_t reg_addr, const uint16_t data);
00070         
00071     protected:
00072         /**
00073          * @param reg_addr 8-bit register address inside the device
00074          * @param data 8-bit data that will be read from the register. This pointer MUST be valid. This array MUST be at least as long as len.
00075          * @param len total number of bytes to read. len must be >= 1.
00076          * @returns 0 on success, otherwise error code from I2C
00077          */ 
00078         int __readReg (const uint8_t reg_addr, uint8_t *data, int len);
00079         
00080         /**
00081          * @param data 8-bit data that will be written to the register. This pointer MUST be valid. This array MUST be at least as long as total_len.
00082          * data[0] should be set to the 8-bit register address. The data payload should start at index 1.
00083          * @param total_len total length of the data array, which is the length of the payload + 1 for the register address. total_len must be >= 2.
00084          * @returns 0 on success, otherwise error code from I2C
00085          */ 
00086         int __writeReg (const uint8_t *data, int total_len);
00087         
00088         PinName __sda_pin;
00089         PinName __scl_pin;  
00090         int __i2c_addr;
00091         uint8_t __who_am_i;
00092         I2C __i2c; //We wrap the mbed i2c SDK functionality
00093 };
00094 
00095 #endif