PCA9547.cpp

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 #include "PCA9547.h"
00019 
00020 PCA9547::PCA9547( PinName sda, PinName scl, char i2c_address )
00021     : i2c_p( new I2C( sda, scl ) ), i2c( *i2c_p ), i2c_addr( i2c_address )
00022 {
00023     //  do nothing.
00024     //  leave it in default state.
00025 }
00026 
00027 PCA9547::PCA9547( I2C &i2c_, char i2c_address )
00028     : i2c_p( NULL ), i2c( i2c_ ), i2c_addr( i2c_address )
00029 {
00030     //  do nothing.
00031     //  leave it in default state.
00032 }
00033 
00034 PCA9547::~PCA9547()
00035 {
00036     if ( NULL != i2c_p )
00037         delete  i2c_p;
00038 }
00039 
00040 void PCA9547::select( char channel )
00041 {
00042     char    data    = 0x08 | channel;
00043 
00044     i2c.write( i2c_addr, &data, 1 );
00045 }
00046 
00047 void PCA9547::disable( void )
00048 {
00049     char    data    = 0x00;
00050 
00051     i2c.write( i2c_addr, &data, 1 );
00052 }