Diff: SoftI2C.h

Revision:

0:fee70b6fe0e9

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SoftI2C.h	Tue Nov 22 20:45:35 2016 +0000
@@ -0,0 +1,95 @@
+#include "mbed.h"
+
+#ifndef SOFTI2C_H
+#define SOFTI2C_H
+
+/**
+* A software I2C class in case you run out of hardware I2C pins or cannot use
+* those for another reason.
+* 
+* The class is a drop-in replacement of the classic mbed I2C class: include 
+* this file in your program, replace I2C with SoftI2C when creating the object
+* and it should work properly without other modifications.
+*/
+class SoftI2C {
+    public:
+    /**
+    * Create an software I2C Master interface, connected to the specified pins
+    *
+    * @param sda I2C data pin 
+    * @param scl I2C clock pin
+    */
+    SoftI2C(PinName sda, PinName scl);
+    
+    /**
+    * Set the frequency of the I2C interface. 
+    *
+    * Note that the delay of the DigitalInOuts is not compensated: the real
+    * frequency will be lower than the one set. However since I2C is a
+    * synchronous protocol this shouldn't affect functionality
+    *
+    * @param hz The bus frequency in hertz 
+    */ 
+    void frequency(int hz);
+    
+    /**
+    * Read from an I2C slave. 
+    * 
+    * Performs a complete read transaction. The bottom bit of the address is forced to 1 to indicate a read.
+    *
+    * @param address 8-bit I2C slave address [ addr | 1 ] 
+    * @param Pointer to the byte-array data to read to 
+    * @param length Number of bytes to read
+    * @param repeated Repeated start, true - do not send stop at end
+    * @return 0 on success (ack), non-0 on failure (nack) 
+    */
+    int read(int address, char *data, int length, bool repeated=false);  
+    
+    /**
+    * Read a single byte from the I2C bus
+    *
+    * @param ack indicates if the byte is to be acknowledged (1 = acknowledge)
+    * @return the byte read
+    */
+    int read(int ack);
+    
+    /**
+    * Write to an I2C slave. 
+    * 
+    * Performs a complete write transaction. The bottom bit of the address is forced to 0 to indicate a write.
+    *
+    * @param address 8-bit I2C slave address [ addr | 0 ] 
+    * @param Pointer to the byte-array data to send 
+    * @param length Number of bytes to send
+    * @param repeated Repeated start, true - do not send stop at end
+    * @return 0 on success (ack), non-0 on failure (nack) 
+    */
+    int write(int address, const char *data, int length, bool repeated=false);  
+    
+    /**
+    * Write single byte out on the I2C bus
+    *
+    * @param data data to write on the bus
+    * @return '1' if an ACK is received, '0' otherwise
+    */
+    int write(int data);
+    
+    /**
+    * Create a (re-)start condition on the I2C bus
+    */
+    void start(void);
+    
+    /**
+    * Create a stop condition on the I2C bus
+    */
+    void stop(void);
+    
+    protected:
+    DigitalInOut _sda;
+    DigitalInOut _scl;
+    int delay_us;
+    bool active;
+};
+
+
+#endif
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