Diff: PCF8574_AddressBus.cpp

Revision:

0:12207c70f4ea

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/PCF8574_AddressBus.cpp	Sun Jan 25 17:50:03 2015 +0000
@@ -0,0 +1,40 @@
+/* PCF8574_AddressBus - Use the PCF8574 I2C Port Extender for controlling the Address Bus
+ * Copyright (c) 2011 Wim Huiskamp
+ *
+ * Released under the MIT License: http://mbed.org/license/mit
+ *
+ * version 0.2 Initial Release
+*/
+#include "mbed.h"
+#include "PCF8574_AddressBus.h"
+
+/** Create an PCF8574_AddressBus object connected to the specified I2C object and using the specified deviceAddress
+ *
+ * @param I2C &i2c the I2C port to connect to 
+ * @param char deviceAddress the address of the PCF8574
+*/
+PCF8574_AddressBus::PCF8574_AddressBus(I2C &i2c, char deviceAddress) : _i2c(i2c) {
+   _writeOpcode = deviceAddress & 0xFE; // low order bit = 0 for write
+   _readOpcode  = deviceAddress | 0x01; // low order bit = 1 for read
+   _init();
+}
+
+/** Optimised AddressBus write operation.
+ * @param address the addressvalue to output on the bus
+*/
+void PCF8574_AddressBus::write(char address) {
+    char data[1];
+    
+    data[0] = address;
+    _i2c.write(_writeOpcode, data, 1);    // Write addressvalue to bus   
+}
+
+
+/** Init PCF8574_AddressBus
+ * @param
+ * @returns 
+ */
+void PCF8574_AddressBus::_init() {
+ 
+    write(0x00);
+}
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