Diff: PCF8574.cpp

Revision:

0:6d75da25c179

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/PCF8574.cpp	Sat Jul 14 08:20:07 2012 +0000
@@ -0,0 +1,210 @@
+/***********************************************************
+Author: Bernard Borredon
+Date: 27 december 2011
+Version: 1.0
+************************************************************/
+#include "PCF8574.h"
+
+// Local object address
+static PCF8574 *pt_pcf8574;
+
+// User callback function address
+static void (*_ptf)(uint8_t data,PCF8574 *o)= NULL;
+
+// Callback
+static void _InterruptCB(void)
+{
+  uint8_t data = 0;
+  bitset<8> data_p,val;
+  bitset<8> changed;
+  uint8_t i;
+  
+  // Read PCF8574 port (to acknowledge interrupt)
+  data = pt_pcf8574->read();
+  
+  // Set bits that have changed
+  pt_pcf8574->getIntrData(data_p,changed);
+  changed = 0;
+  val = data;
+  for(i = 0;i < 8;i++) {
+     if(val[i] != data_p[i])
+       changed[i] = 1;
+  }
+  pt_pcf8574->setIntrData(val,changed);
+  
+  // Call user callback, if any with port value
+  if(_ptf != NULL)
+    _ptf(data,pt_pcf8574);
+}
+
+// Constructor
+PCF8574::PCF8574(PinName sda,PinName scl,uint8_t address, bool typeA) : _i2c(sda, scl)
+{
+  _errnum = PCF8574_NoError;
+  _intr = NULL;
+  pt_pcf8574 = NULL;
+  _intr_data = 0xFF;
+  _intr_bits_changed = 0;
+  _intr_flag = 0;
+  
+  // Set the address
+  if(typeA) {  // PCF8574A
+    _PCF8574_address = 0x70;
+  }
+  else {       // PCF8574
+    _PCF8574_address = 0x40;
+  }
+  
+  _address = address;
+  
+  // Check address validity (between 0 and 7)
+  if(address > 7) {
+    _errnum = PCF8574_BadAddress;
+  }
+  
+  // Shift address
+  _address = _address << 1;
+  
+  // Set I2C frequency (100 MHz)
+  _i2c.frequency(100000);
+}
+
+// Read IO port
+uint8_t PCF8574::read(void)
+{
+  uint8_t data;
+  int ack;
+  
+  // Check error
+  if(_errnum) 
+    return(0);
+  
+  // No error
+  _errnum = PCF8574_NoError;
+    
+  // Read port
+  ack = _i2c.read(_PCF8574_address | _address,(char *)&data,sizeof(data));
+  
+  // Check error
+  if(ack != 0) {
+    _errnum = PCF8574_I2cError;
+  }
+  
+  return(data);
+}
+
+// Write IO port
+void PCF8574::write(uint8_t data)
+{
+  int ack;
+  
+  // Check error
+  if(_errnum) 
+    return;
+ 
+  // No error   
+  _errnum = PCF8574_NoError;
+    
+  // Write port
+  ack = _i2c.write(_PCF8574_address | _address,(char *)&data,sizeof(data));
+  
+  // Check error
+  if(ack != 0) {
+    _errnum = PCF8574_I2cError;
+  }
+}
+
+// Write IO pin
+void PCF8574::write(uint8_t pin, uint8_t value)
+{
+  uint8_t data;
+  
+  // Read IO port value
+  data = read();
+  
+  // Change bit pin
+  if(value)
+    BIT_SET(data,pin);
+  else
+    BIT_CLEAR(data,pin);
+    
+  // Write new IO port data
+  write(data);
+}
+
+// Write to IO pins with a bitset and a bitset mask
+void PCF8574::write(bitset<8> data, bitset<8> mask)
+{
+  uint8_t i;
+  bitset<8> nd;
+  
+  nd = (bitset<8>) read();
+  for(i = 0;i < 8;i++) {
+     if(mask[i])
+       nd[i] = data[i];
+  }
+  
+  write((uint8_t) nd.to_ulong());
+}
+
+// Set pin and callback interrupt
+void PCF8574::interrupt(PinName intr,void (*ftpr)(uint8_t, PCF8574 *))
+{
+  
+  // Check error
+  if(_errnum) 
+    return;
+    
+  // No error
+  _errnum = PCF8574_NoError;
+    
+  // Create InterruptIn instance if needed
+  if(_intr == NULL) {
+    _intr = new InterruptIn(intr);
+    
+    // Set InterruptIn callback
+    if(_intr != NULL)
+      _intr->fall(_InterruptCB);
+    else
+      _errnum = PCF8574_IntrError;
+  }
+  
+  _ptf = ftpr; // User callback address
+  pt_pcf8574 = this; // Object instance
+  _intr_data = read(); // IO port value
+  _intr_flag = 1; // Function called
+}
+
+// Get current error number
+uint8_t PCF8574::getError(void)
+{ 
+  return(_errnum);
+}
+
+// Memorize IO port value and bits that have changed when interrupt
+ void PCF8574::setIntrData(bitset<8> data, bitset<8> changed)
+ {
+   _intr_data = data;
+   _intr_bits_changed = changed;
+ }
+ 
+ // Get IO port value and bits that have changed when interrupt
+ void PCF8574::getIntrData(bitset<8>& data, bitset<8>& changed)
+ {
+   data = _intr_data;
+   changed = _intr_bits_changed;
+ }
+
+// Redefine () operator
+PCF8574::operator uint8_t() 
+{ 
+  return read(); 
+}
+ 
+// Redefine = operator
+PCF8574 &PCF8574::operator=(uint8_t data)
+{
+  write((int)data);
+  
+  return(*this);
+}
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