Diff: PCF8574.h

Revision:

0:6d75da25c179

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/PCF8574.h	Sat Jul 14 08:20:07 2012 +0000
@@ -0,0 +1,202 @@
+#ifndef PCF8574__H_
+#define PCF8574__H_
+
+// Includes
+#include <string> 
+#include <bitset>
+
+#include "mbed.h"
+
+// Example
+/*
+#include <string>
+
+#include "mbed.h"
+#include "PCF8574.h"
+
+#define PCF8574_ADDR 0    // I2c PCF8574 address is 0x00
+
+static void myerror(std::string msg)
+{
+  printf("Error %s\n",msg.c_str());
+  exit(1);
+}
+
+void pcf8574_it(uint8_t data, PCF8574 *o)
+{
+  printf("PCF8574 interrupt data = %02x\n",data);
+}
+
+DigitalOut led2(LED2);
+
+int main() 
+{
+  PCF8574 pcf(p9,p10,PCF8574_ADDR,true);  // Declare PCF8574A i2c with sda = p9 and scl = p10
+  uint8_t data;
+  
+  led2 = 0;
+  
+  // Set all IO port bits to 1 to enable inputs and test error
+  data = 0xFF;
+  pcf = data;
+  if(pcf.getError() != 0)
+    myerror(pcf.getErrorMessage());
+  
+  // Assign interrupt function to pin 17  
+  pcf.interrupt(p17,&pcf8574_it);
+  
+  if(pcf.getError() != 0)
+    myerror(pcf.getErrorMessage());
+  
+  // Get IO port (switch is used to flip bit 1)
+  while(1) {
+             wait(2.0);
+             data = pcf;
+             if(pcf.getError() != 0)
+               myerror(pcf.getErrorMessage());
+             led2 = !led2;
+  }
+
+  return(0);
+}
+*/
+
+// Defines
+#define PCF8574_NoError     0x00
+#define PCF8574_BadAddress  0x01
+#define PCF8574_I2cError    0x02
+#define PCF8574_IntrError   0x03
+
+#define PCF8574_MaxError       4
+
+#ifndef BIT_SET
+#define BIT_SET(x,n) (x=x | (0x01<<n))
+#endif
+#ifndef BIT_TEST
+#define BIT_TEST(x,n) (x & (0x01<<n))
+#endif
+#ifndef BIT_CLEAR
+#define BIT_CLEAR(x,n) (x=x & ~(0x01<<n))
+#endif
+#ifndef BIT_GET
+#define BIT_GET(x,n) ((x >>n) & 0x1)
+#endif
+
+static std::string _ErrorMessagePCF8574[PCF8574_MaxError] = {
+                                                              "",
+                                                              "Bad chip address",
+                                                              "I2C error (nack)",
+                                                              "Unable to create InterruptIn instance"
+                                                            };
+
+// Class
+class PCF8574 {
+public:               
+    /*
+     * Constructor, initialize the PCF8574 on i2c interface.
+     * @param sda : sda i2c pin (PinName)
+     * @param scl : scl i2c pin (PinName)
+     * @param address : PCF8574 address between 0 and 7 (uint8_t) 
+     * @param typeA : PCF8574A if true, default false (bool)
+     * @return none
+    */
+    PCF8574(PinName sda, PinName scl, uint8_t address, bool typeA = false);
+
+    /*
+     * Read the IO pins level
+     * @param : none
+     * @return port value (uint8_t)
+    */
+    uint8_t read(void);
+    
+    /*
+     * Write to the IO pins
+     * @param data : The 8 bits to write to the IO port (uint8_t)
+     * @return none
+    */
+    void write(uint8_t data);
+    
+    /*
+     * Write to individual IO pin
+     * @param pin : The pin number between 0 and 7 (uint8_t)
+     * @param value : The pin value (uint8_t)
+     * @return none
+    */
+    void write(uint8_t pin, uint8_t value);
+    
+    /*
+     * Write to IO pins with a bitset and a bitset mask (only bits set in mask are written)
+     * @param data : The biset to write to the IO port (bitset<8>)
+     * @param mask : The biset to write mask (bitset<8>)
+     * @return none
+    */
+    void write(bitset<8> data, bitset<8> mask);
+    
+    /*
+     * Interrupt IO callback called when PCF8574 IO pins changed (falling edge)
+     * @param intr : pin name connected to PCF8574 int pin (PinName)
+     * @param ftpr : user callback function (void ftpr(unit8_t data, PCF8574 *o)).
+     *                 data : PCF8574 IO port value
+     *                 o    : object instance address
+     * @return none
+    */
+    void interrupt(PinName intr,void (*ftpr)(uint8_t data, PCF8574 *o));
+    
+    /*
+     * Get current error message
+     * @param  : none
+     * @return current error message(std::string)
+    */
+    std::string getErrorMessage(void)
+    { 
+      if(_errnum < PCF8574_MaxError)
+        return(_ErrorMessagePCF8574[_errnum]);
+      else
+        return("errnum out of range");
+    }
+    
+    /*
+     * Get the current error number (PCF8574_NoError if no error)
+     * @param  : none
+     * @return current error number (uint8_t)
+    */
+    uint8_t getError(void);
+     
+    /*
+     * Memorize data IO port value and bits that have changed when interrupt
+     * @param data : data IO port value when interrupt (bitset<8>)
+     * @param changed : bits that have changed (bitset<8>) 
+     * @return none
+    */
+     void setIntrData(bitset<8> data, bitset<8> changed);
+     
+    /*
+     * Get data IO port value when and bits that have changed when interrupt 
+     * @param data : data IO port value when interrupt (bitset<8>&) 
+     * @param changed : bits that have changed (bitset<8>&)
+     * @return none
+    */
+     void getIntrData(bitset<8>& data, bitset<8>& changed);
+    
+    /*
+     *Operator () (read)
+    */
+    operator uint8_t();
+    
+    /* 
+     *Operator = (write)
+    */
+    PCF8574 &operator=(uint8_t data);
+    
+private:
+    I2C _i2c; // Local i2c communication interface instance
+    int _address; // Local pcf8574 i2c address
+    int _PCF8574_address; // PCF8574 address
+    uint8_t _errnum; // Error number
+    bitset<8> _intr_data; // IO port value when interrupt
+    bitset<8> _intr_bits_changed; // Bits that have changed on interrupt 
+    InterruptIn *_intr; // Internal InterruptIn object address
+    uint8_t _intr_flag; // interrupt function has been called
+};
+
+#endif
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