PCA9546A.h

00001 /**
00002  *  PCA9546A library
00003  *
00004  *  @author  Tedd OKANO
00005  *  @version 0.1
00006  *  @date    Feb-2015
00007  *
00008  *  PCA9546A: an I2C bus switch control library
00009  *
00010  *  The PCA9546A is a quad bidirectional translating switch controlled 
00011  *  via the I2C-bus. The SCL/SDA upstream pair fans out to four downstream 
00012  *  pairs, or channels. Any individual SCx/SDx channel or combination of 
00013  *  channels can be selected, determined by the contents of the programmable 
00014  *  control register.
00015  *
00016  *  For more information about PCA9546A:
00017  *    http://www.nxp.com/documents/data_sheet/PCA9546A.pdf
00018  *
00019  */
00020 
00021 #ifndef MBED_PCA9546A_H
00022 #define MBED_PCA9546A_H
00023 
00024 #include "mbed.h"
00025 
00026 /** PCA9546A class
00027  *
00028  *  PCA9546A: an I2C bus switch control library
00029  *
00030  *  The PCA9546A is a quad bidirectional translating switch controlled 
00031  *  via the I2C-bus. The SCL/SDA upstream pair fans out to four downstream 
00032  *  pairs, or channels. Any individual SCx/SDx channel or combination of 
00033  *  channels can be selected, determined by the contents of the programmable 
00034  *  control register.
00035  *
00036  *  For more information about PCA9546A:
00037  *    http://www.nxp.com/documents/data_sheet/PCA9546A.pdf
00038  *
00039  *  Example:
00040  *  @code
00041  *  #include "mbed.h"
00042  *  #include "LM75B.h"
00043  *  #include "PCA9546A.h"
00044  *  
00045  *  PCA9546A    i2c_sw( p28, p27, 0xE0 );
00046  *  
00047  *  int main()
00048  *  {
00049  *      //  all PCA9546A's downstream ports are OFF after power-up and hardware-reset
00050  *      
00051  *      i2c_sw.on( 0 );     //  turn-ON  the channel 0
00052  *  
00053  *      LM75B   tmp0( p28, p27 );   //  making instance after a branch of I2C bus (which is connecting the LM75B) enabled
00054  *  
00055  *      i2c_sw.off( 0 );    //  turn-OFF the channel 0
00056  *      i2c_sw.on( 1 );     //  turn-ON  the channel 1
00057  *  
00058  *      LM75B   tmp1( p28, p27 );   //  making instance after a branch of I2C bus (which is connecting the LM75B) enabled
00059  *  
00060  *      while(1) {
00061  *          
00062  *          i2c_sw.off( 1 );    //  turn-OFF the channel 1
00063  *          i2c_sw.on( 0 );     //  turn-ON  the channel 0
00064  *          printf( "%.3f\r\n", tmp0.read() );
00065  *  
00066  *          i2c_sw.off( 0 );    //  turn-OFF the channel 0
00067  *          i2c_sw.on( 1 );     //  turn-ON  the channel 1
00068  *          printf( "%.3f\r\n", tmp1.read() );
00069  *  
00070  *          wait( 1.0 );
00071  *      }
00072  *  }
00073  *  @endcode
00074  */
00075 
00076 class PCA9546A
00077 {
00078 public:
00079 
00080     /** Create a PCA9546A instance connected to specified I2C pins with specified address
00081      *
00082      * @param sda I2C-bus SDA pin
00083      * @param scl I2C-bus SCL pin
00084      * @param i2c_address I2C-bus address (default: 0xE0)
00085      */
00086     PCA9546A( PinName sda, PinName scl, char i2c_address = 0xE0 );
00087 
00088     /** Create a PCA9546A instance connected to specified I2C pins with specified address
00089      *
00090      * @param &i2c_ I2C object (instance)
00091      * @param i2c_address I2C-bus address (default: 0xE0)
00092      */
00093     PCA9546A( I2C &i2c_, char i2c_address = 0xE0 );
00094 
00095     /** Destructor of PCA9546A
00096      */
00097     ~PCA9546A();
00098 
00099     /** Turning-ON a channel
00100      *
00101      *  Switching a channel ON
00102      *
00103      * @param channel channel number
00104      */
00105     void on( char channel );
00106 
00107     /** Turning-OFF a channel
00108      *
00109      *  Switching a channel OFF
00110      *
00111      * @param channel channel number
00112      */
00113     void off( char channel );
00114 
00115     /** Switching by bit pattern
00116      *
00117      *  Switch setting by bit pattern. 
00118      *  Set '1' for ON, set '0' for OFF
00119      *  LSB is channel 0. Channels 1, 2 and 3 are mapped in shifted position from LSB
00120      *
00121      *  @param pattern ON/OFF bit pattern for channels
00122      */
00123     void bitpattern( char pattern );
00124 
00125 private:
00126     I2C     *i2c_p;
00127     I2C     &i2c;
00128     char    i2c_addr;
00129     char    enable_pattern;
00130 };
00131 
00132 #endif  //  MBED_PCA9546A_H