openXsensor/I2C.h

   1 /*
   2   I2C.h   - I2C library
   3   Copyright (c) 2011-2012 Wayne Truchsess.  All right reserved.
   4   Rev 5.0 - January 24th, 2012
   5           - Removed the use of interrupts completely from the library
   6             so TWI state changes are now polled.
   7           - Added calls to lockup() function in most functions
   8             to combat arbitration problems
   9           - Fixed scan() procedure which left timeouts enabled
  10             and set to 80msec after exiting procedure
  11           - Changed scan() address range back to 0 - 0x7F
  12           - Removed all Wire legacy functions from library
  13           - A big thanks to Richard Baldwin for all the testing
  14             and feedback with debugging bus lockups!
  15   Rev 4.0 - January 14th, 2012
  16           - Updated to make compatible with 8MHz clock frequency
  17   Rev 3.0 - January 9th, 2012
  18           - Modified library to be compatible with Arduino 1.0
  19           - Changed argument type from boolean to uint8_t in pullUp(),
  20             setSpeed() and receiveByte() functions for 1.0 compatability
  21           - Modified return values for timeout feature to report
  22             back where in the transmission the timeout occured.
  23           - added function scan() to perform a bus scan to find devices
  24             attached to the I2C bus.  Similar to work done by Todbot
  25             and Nick Gammon
  26   Rev 2.0 - September 19th, 2011
  27           - Added support for timeout function to prevent
  28             and recover from bus lockup (thanks to PaulS
  29             and CrossRoads on the Arduino forum)
  30           - Changed return type for stop() from void to
  31             uint8_t to handle timeOut function
  32   Rev 1.0 - August 8th, 2011
  33
  34   This is a modified version of the Arduino Wire/TWI
  35   library.  Functions were rewritten to provide more functionality
  36   and also the use of Repeated Start.  Some I2C devices will not
  37   function correctly without the use of a Repeated Start.  The
  38   initial version of this library only supports the Master.
  39
  40
  41   This library is free software; you can redistribute it and/or
  42   modify it under the terms of the GNU Lesser General Public
  43   License as published by the Free Software Foundation; either
  44   version 2.1 of the License, or (at your option) any later version.
  45
  46   This library is distributed in the hope that it will be useful,
  47   but WITHOUT ANY WARRANTY; without even the implied warranty of
  48   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  49   Lesser General Public License for more details.
  50
  51   You should have received a copy of the GNU Lesser General Public
  52   License along with this library; if not, write to the Free Software
  53   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  54 */
  55
  56 #if(ARDUINO >= 100)
  57 #include <Arduino.h>
  58 #else
  59 #include <WProgram.h>
  60 #endif
  61
  62 #include <inttypes.h>
  63
  64 #ifndef I2C_h
  65 #define I2C_h
  66
  67
  68 #define START           0x08
  69 #define REPEATED_START  0x10
  70 #define MT_SLA_ACK      0x18
  71 #define MT_SLA_NACK     0x20
  72 #define MT_DATA_ACK     0x28
  73 #define MT_DATA_NACK    0x30
  74 #define MR_SLA_ACK      0x40
  75 #define MR_SLA_NACK     0x48
  76 #define MR_DATA_ACK     0x50
  77 #define MR_DATA_NACK    0x58
  78 #define LOST_ARBTRTN    0x38
  79 #define TWI_STATUS      (TWSR & 0xF8)
  80 #define SLA_W(address)  (address << 1)
  81 #define SLA_R(address)  ((address << 1) + 0x01)
  82 #define cbi(sfr, bit)   (_SFR_BYTE(sfr) &= ~_BV(bit))
  83 #define sbi(sfr, bit)   (_SFR_BYTE(sfr) |= _BV(bit))
  84
  85 #define MAX_BUFFER_SIZE 32
  86
  87 class I2C {
  88   public:
  89     I2C();
  90     void begin();
  91     void end();
  92     void timeOut(uint16_t);
  93     void setSpeed(uint8_t);
  94     void pullup(uint8_t);
  95     void scan();
  96     uint8_t available();
  97     uint8_t receive();
  98     uint8_t write(uint8_t, uint8_t);
  99 //    uint8_t write(int, int);
 100     uint8_t write(uint8_t, uint8_t, uint8_t);
 101 //    uint8_t write(int, int, int);
 102     uint8_t write(uint8_t, uint8_t, char*);
 103     uint8_t write(uint8_t, uint8_t,  uint8_t , uint8_t* );
 104     uint8_t read(uint8_t, uint8_t);
 105 //    uint8_t read(int, int);
 106     uint8_t read(uint8_t, uint8_t, uint8_t);
 107 //    uint8_t read(int, int, int);
 108     uint8_t read(uint8_t, uint8_t, uint8_t*);
 109     uint8_t read(uint8_t, uint8_t, uint8_t, uint8_t* );
 110
 111     uint8_t scanAdr ;
 112
 113   private:
 114     uint8_t start();
 115     uint8_t sendAddress(uint8_t);
 116     uint8_t sendByte(uint8_t);
 117     uint8_t receiveByte(uint8_t);
 118     uint8_t stop();
 119     void lockUp();
 120     uint8_t returnStatus;
 121     uint8_t nack;
 122     uint8_t data[MAX_BUFFER_SIZE];
 123     static uint8_t bytesAvailable;
 124     static uint8_t bufferIndex;
 125     static uint8_t totalBytes;
 126     static uint16_t timeOutDelay;
 127
 128 };
 129
 130 extern I2C I2c;
 131
 132 #endif
 133