LUFA/Drivers/Peripheral/AVR8/TWI.h

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2010.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6       www.fourwalledcubicle.com
   7 */
   8
   9 /*
  10   Copyright 2010  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  11
  12   Permission to use, copy, modify, distribute, and sell this
  13   software and its documentation for any purpose is hereby granted
  14   without fee, provided that the above copyright notice appear in
  15   all copies and that both that the copyright notice and this
  16   permission notice and warranty disclaimer appear in supporting
  17   documentation, and that the name of the author not be used in
  18   advertising or publicity pertaining to distribution of the
  19   software without specific, written prior permission.
  20
  21   The author disclaim all warranties with regard to this
  22   software, including all implied warranties of merchantability
  23   and fitness.  In no event shall the author be liable for any
  24   special, indirect or consequential damages or any damages
  25   whatsoever resulting from loss of use, data or profits, whether
  26   in an action of contract, negligence or other tortious action,
  27   arising out of or in connection with the use or performance of
  28   this software.
  29 */
  30
  31 /** \file
  32  *
  33  *  Master mode TWI driver for the 8-Bit AVRs containing a hardware TWI module.
  34  *
  35  *  \note This file should not be included directly. It is automatically included as needed by the TWI driver
  36  *        dispatch header located in LUFA/Drivers/Peripheral/TWI.h.
  37  */
  38
  39 /** \ingroup Group_TWI
  40  *  @defgroup Group_TWI_AVR8 Series U4, U6 and U7 Model TWI Driver
  41  *
  42  *  Master mode TWI driver for the 8-Bit AVRs containing a hardware TWI module.
  43  *
  44  *  \note This file should not be included directly. It is automatically included as needed by the TWI driver
  45  *        dispatch header located in LUFA/Drivers/Peripheral/TWI.h.
  46  *
  47  *  @{
  48  */
  49
  50 #ifndef __TWI_AVR8_H__
  51 #define __TWI_AVR8_H__
  52
  53         /* Includes: */
  54                 #include "../../../Common/Common.h"
  55
  56                 #include <avr/io.h>
  57                 #include <stdbool.h>
  58                 #include <util/twi.h>
  59
  60         /* Enable C linkage for C++ Compilers: */
  61                 #if defined(__cplusplus)
  62                         extern "C" {
  63                 #endif
  64
  65         /* Preprocessor Checks: */
  66                 #if !defined(__INCLUDE_FROM_TWI_H)
  67                         #error Do not include this file directly. Include LUFA/Drivers/Peripheral/TWI.h instead.
  68                 #endif
  69
  70         /* Public Interface - May be used in end-application: */
  71                 /* Pseudo-Function Macros: */
  72                         #if defined(__DOXYGEN__)
  73                                 /** Initializes the TWI hardware into master mode, ready for data transmission and reception. This must be
  74                                  *  before any other TWI operations.
  75                                  */
  76                                 static inline void TWI_Init(void);
  77
  78                                 /** Turns off the TWI driver hardware. If this is called, any further TWI operations will require a call to
  79                                  *  \ref TWI_Init() before the TWI can be used again.
  80                                  */
  81                                 static inline void TWI_ShutDown(void);
  82                         #else
  83                                 #define TWI_Init()        MACROS{ TWCR |=  (1 << TWEN); }MACROE
  84                                 #define TWI_ShutDown()    MACROS{ TWCR &= ~(1 << TWEN); }MACROE
  85                         #endif
  86
  87                 /* Inline Functions: */
  88                         /** Sends a TWI STOP onto the TWI bus, terminating communication with the currently addressed device. */
  89                         static inline void TWI_StopTransmission(void)
  90                         {
  91                                 TWCR = ((1 << TWINT) | (1 << TWSTO) | (1 << TWEN));
  92                         }
  93
  94                         /** Sends a byte to the currently addressed device on the TWI bus.
  95                          *
  96                          *  \param[in] Byte  Byte to send to the currently addressed device
  97                          *
  98                          *  \return Boolean true if the recipient ACKed the byte, false otherwise
  99                          */
 100                         static inline bool TWI_SendByte(uint8_t Byte)
 101                         {
 102                                 TWDR = Byte;
 103                                 TWCR = ((1 << TWINT) | (1 << TWEN));
 104                                 while (!(TWCR & (1 << TWINT)));
 105
 106                                 return ((TWSR & TW_STATUS_MASK) == TW_MT_DATA_ACK);
 107                         }
 108
 109                         /** Receives a byte from the currently addressed device on the TWI bus.
 110                          *
 111                          *  \param[in] Byte  Location where the read byte is to be stored
 112                          *  \param[in] LastByte  Indicates if the byte should be ACKed if false, NAKed if true
 113                          *
 114                          *  \return Boolean true if the byte reception sucessfully completed, false otherwise
 115                          */
 116                         static inline bool TWI_ReceiveByte(uint8_t* Byte, bool LastByte)
 117                         {
 118                                 uint8_t TWCRMask = ((1 << TWINT) | (1 << TWEN));
 119
 120                                 if (!(LastByte))
 121                                   TWCRMask |= (1 << TWEA);
 122
 123                                 TWCR = TWCRMask;
 124                                 while (!(TWCR & (1 << TWINT)));
 125                                 *Byte = TWDR;
 126
 127                                 return ((TWSR & TW_STATUS_MASK) == TW_MR_DATA_ACK);
 128                         }
 129
 130                 /* Function Prototypes: */
 131                         /** Begins a master mode TWI bus communication with the given slave device address.
 132                          *
 133                          *  \param[in] SlaveAddress  Address of the slave TWI device to communicate with
 134                          *
 135                          *  \return Boolean true if the device is ready for data, false otherwise
 136                          */
 137                         bool TWI_StartTransmission(uint8_t SlaveAddress);
 138
 139         /* Disable C linkage for C++ Compilers: */
 140                 #if defined(__cplusplus)
 141                         }
 142                 #endif
 143
 144 #endif
 145
 146 /** @} */