I2C.h

00001 /* mbed Microcontroller Library - I2C
00002  * Copyright (c) 2007-2011 ARM Limited. All rights reserved.
00003  */ 
00004  
00005 #ifndef MBED_I2C_H
00006 #define MBED_I2C_H
00007 
00008 #include "device.h"
00009 
00010 #if DEVICE_I2C
00011 
00012 #include "platform.h"
00013 #include "PinNames.h"
00014 #include "PeripheralNames.h"
00015 #include "Base.h"
00016 
00017 namespace mbed {
00018 
00019 /** An I2C Master, used for communicating with I2C slave devices
00020  *
00021  * Example:
00022  * @code
00023  * // Read from I2C slave at address 0x62
00024  *
00025  * #include "mbed.h"
00026  *
00027  * I2C i2c(p28, p27);
00028  *
00029  * int main() {
00030  *     int address = 0x62;
00031  *     char data[2];
00032  *     i2c.read(address, data, 2);
00033  * }
00034  * @endcode
00035  */
00036 class I2C : public Base {
00037 
00038 public:
00039 
00040     enum RxStatus {
00041         NoData
00042         , MasterGeneralCall
00043         , MasterWrite
00044         , MasterRead
00045     };
00046 
00047     enum Acknowledge {
00048           NoACK = 0
00049         , ACK   = 1
00050     };
00051 
00052     /** Create an I2C Master interface, connected to the specified pins
00053      *
00054      *  @param sda I2C data line pin
00055      *  @param scl I2C clock line pin
00056      */
00057     I2C(PinName sda, PinName scl, const char *name = NULL);
00058 
00059     /** Set the frequency of the I2C interface
00060      *
00061      *  @param hz The bus frequency in hertz
00062      */
00063     void frequency(int hz);
00064 
00065     /** Read from an I2C slave
00066      *
00067      *  Performs a complete read transaction. The bottom bit of
00068      *  the address is forced to 1 to indicate a read.
00069      *
00070      *  @param address 8-bit I2C slave address [ addr | 1 ]
00071      *  @param data Pointer to the byte-array to read data in to 
00072      *  @param length Number of bytes to read
00073      *  @param repeated Repeated start, true - don't send stop at end
00074      *
00075      *  @returns
00076      *       0 on success (ack),
00077      *   non-0 on failure (nack)
00078      */ 
00079     int read(int address, char *data, int length, bool repeated = false); 
00080 
00081     /** Read a single byte from the I2C bus
00082      *
00083      *  @param ack indicates if the byte is to be acknowledged (1 = acknowledge)
00084      *
00085      *  @returns
00086      *    the byte read
00087      */
00088     int read(int ack);
00089 
00090     /** Write to an I2C slave
00091      *
00092      *  Performs a complete write transaction. The bottom bit of
00093      *  the address is forced to 0 to indicate a write.
00094      *
00095      *  @param address 8-bit I2C slave address [ addr | 0 ]
00096      *  @param data Pointer to the byte-array data to send 
00097      *  @param length Number of bytes to send
00098      *  @param repeated Repeated start, true - do not send stop at end
00099      *
00100      *  @returns
00101      *       0 on success (ack),
00102      *   non-0 on failure (nack)
00103      */ 
00104     int write(int address, const char *data, int length, bool repeated = false);
00105 
00106     /** Write single byte out on the I2C bus
00107      *
00108      *  @param data data to write out on bus
00109      *
00110      *  @returns
00111      *    '1' if an ACK was received,
00112      *    '0' otherwise
00113      */
00114     int write(int data);
00115 
00116     /** Creates a start condition on the I2C bus
00117      */
00118     void start(void);
00119 
00120     /** Creates a stop condition on the I2C bus
00121      */
00122     void stop(void);
00123 
00124 protected:
00125 
00126     void aquire();
00127 
00128     I2CName     _i2c;
00129     static I2C  *_owner;
00130     int         _hz;
00131 
00132 };
00133 
00134 } // namespace mbed
00135 
00136 #endif
00137 
00138 #endif
00139