PCA9547.h

00001 /**
00002  *  PCA9547 library
00003  *
00004  *  @author  Tedd OKANO
00005  *  @version 0.2
00006  *  @date    Feb-2015
00007  *
00008  *  PCA9547: an I2C bus multiplexer control library
00009  *
00010  *  PCA9547 is an I2C multiplexer which enables to select 1:8 multiplexed I2C bus.
00011  *  The multiplexer is useful for deviding I2C bus to avoiding slave address conflict and separating capacitive loads.
00012  *
00013  *  For more information about PCA9547:
00014  *    http://www.nxp.com/documents/data_sheet/PCA9547.pdf
00015  *
00016  */
00017 
00018 #ifndef MBED_PCA9547_H
00019 #define MBED_PCA9547_H
00020 
00021 #include "mbed.h"
00022 
00023 /** PCA9547 class
00024  *
00025  *  PCA9547: an I2C bus multiplexer control library
00026  *
00027  *  PCA9547 is an I2C multiplexer which enables to select 1:8 multiplexed I2C bus.
00028  *  The multiplexer is useful for deviding I2C bus to avoiding slave address conflict and separating capacitive loads.
00029  *
00030  *  For more informatioj about PCA9547:
00031  *    http://www.nxp.com/documents/data_sheet/PCA9547.pdf
00032  *
00033  *  Example:
00034  *  @code
00035  *  #include "mbed.h"
00036  *  #include "LM75B.h"
00037  *  #include "PCA9547.h"
00038  *
00039  *  PCA9547 mux( p28, p27, 0xE0 );
00040  *
00041  *  int main()
00042  *  {
00043  *      mux.select( 0 );
00044  *
00045  *      LM75B   tmp0( p28, p27 );   //  making instance after a branch of I2C bus (which is connecting the LM75B) enabled
00046  *
00047  *      while(1) {
00048  *          printf( "%.3f\r\n", tmp0.read() );
00049  *          wait( 1.0 );
00050  *      }
00051  *  }
00052  *  @endcode
00053  */
00054 
00055 class PCA9547
00056 {
00057 public:
00058 
00059     /** Create a PCA9547 instance connected to specified I2C pins with specified address
00060      *
00061      * @param sda I2C-bus SDA pin
00062      * @param scl I2C-bus SCL pin
00063      * @param i2c_address I2C-bus address (default: 0xE0)
00064      */
00065     PCA9547( PinName sda, PinName scl, char i2c_address = 0xE0 );
00066 
00067     /** Create a PCA9546A instance connected to specified I2C pins with specified address
00068      *
00069      * @param &i2c_ I2C object (instance)
00070      * @param i2c_address I2C-bus address (default: 0xE0)
00071      */
00072     PCA9547( I2C &i2c_, char i2c_address = 0xE0 );
00073 
00074     /** Destructor of PCA9547
00075      */
00076     ~PCA9547();
00077 
00078     /** Channel select
00079      *
00080      *  Enable and select a channel
00081      *
00082      * @param channel channel number
00083      */
00084     void select( char channel );
00085 
00086     /** Disabling all channels
00087      *
00088      *  Disable all channels
00089      */
00090     void disable( void );
00091 
00092 private:
00093     I2C     *i2c_p;
00094     I2C     &i2c;
00095     char    i2c_addr;
00096 };
00097 
00098 #endif  //  MBED_PCA9547_H