Tedd OKANO / PCA9547

PCA9547: an I2C bus multiplexer control library. PCA9547 is an I2C multiplexer which enables to select 1:8 multiplexed I2C bus. The multiplexer is useful for deviding I2C bus to avoiding slave address conflict and separating capacitive loads. For more information about PCA9547: http://www.nxp.com/documents/data_sheet/PCA9547.pdf

Dependents:   pca9547_Hello m3Dpi

/media/uploads/okano/pca9547_connections.png

Information

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The PCA9547 is an octal bidirectional translating multiplexer controlled by the I2C-bus. The SCL/SDA upstream pair fans out to eight downstream pairs, or channels.

pca9547

Diff: PCA9547.cpp

Revision:
5:f4f72501148a
Parent:
4:3c0af4c37587
Child:
6:33ef755248e0
--- a/PCA9547.cpp	Tue Jul 01 00:37:01 2014 +0000
+++ b/PCA9547.cpp	Mon Feb 23 06:25:45 2015 +0000
@@ -17,7 +17,15 @@
 
 #include "PCA9547.h"
 
-PCA9547::PCA9547( PinName sda, PinName scl, char i2c_address ) : i2c( sda, scl ), _i2c_addr( i2c_address )
+PCA9547::PCA9547( PinName sda, PinName scl, char i2c_address )
+    : i2c_p( new I2C( sda, scl ) ), i2c( *i2c_p ), i2c_addr( i2c_address )
+{
+    //  do nothing.
+    //  leave it in default state.
+}
+
+PCA9547::PCA9547( I2C &i2c_, char i2c_address )
+    : i2c_p( NULL ), i2c( i2c_ ), i2c_addr( i2c_address )
 {
     //  do nothing.
     //  leave it in default state.
@@ -25,19 +33,20 @@
 
 PCA9547::~PCA9547()
 {
-
+    if ( NULL != i2c_p )
+        delete  i2c_p;
 }
 
 void PCA9547::select( char channel )
 {
     char    data    = 0x08 | channel;
 
-    i2c.write( _i2c_addr, &data, 1 );
+    i2c.write( i2c_addr, &data, 1 );
 }
 
 void PCA9547::disable( void )
 {
     char    data    = 0x00;
 
-    i2c.write( _i2c_addr, &data, 1 );
+    i2c.write( i2c_addr, &data, 1 );
 }