LUFA/Drivers/Peripheral/AVRU4U6U7/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  *  \brief TWI peripheral driver for the U7, U6 and U4 USB AVRs.
  33  *
  34  *  Master mode TWI driver for the AT90USB1287, AT90USB1286, AT90USB647, AT90USB646, ATMEGA16U4 and ATMEGA32U4 AVRs.
  35  *
  36  *  \note This file should not be included directly. It is automatically included as needed by the TWI driver
  37  *        dispatch header located in LUFA/Drivers/Peripheral/TWI.h.
  38  */
  39
  40 /** \ingroup Group_TWI
  41  *  @defgroup Group_TWI_AVRU4U6U7 Series U4, U6 and U7 Model TWI Driver
  42  *
  43  *  Master mode TWI driver for the AT90USB1287, AT90USB1286, AT90USB647, AT90USB646, ATMEGA16U4 and ATMEGA32U4 AVRs.
  44  *
  45  *  \note This file should not be included directly. It is automatically included as needed by the TWI driver
  46  *        dispatch header located in LUFA/Drivers/Peripheral/TWI.h.
  47  *
  48  *  @{
  49  */
  50
  51 #ifndef __TWI_AVRU4U6U7_H__
  52 #define __TWI_AVRU4U6U7_H__
  53
  54         /* Includes: */
  55                 #include "../../../Common/Common.h"
  56
  57                 #include <avr/io.h>
  58                 #include <stdbool.h>
  59                 #include <util/twi.h>
  60                 #include <util/delay.h>
  61
  62         /* Enable C linkage for C++ Compilers: */
  63                 #if defined(__cplusplus)
  64                         extern "C" {
  65                 #endif
  66
  67         /* Preprocessor Checks: */
  68                 #if !defined(__INCLUDE_FROM_TWI_H)
  69                         #error Do not include this file directly. Include LUFA/Drivers/Peripheral/TWI.h instead.
  70                 #endif
  71
  72         /* Public Interface - May be used in end-application: */
  73                 /* Inline Functions: */
  74                         /** Initialises the TWI hardware into master mode, ready for data transmission and reception. This must be
  75                          *  before any other TWI operations.
  76                          */
  77                         static inline void TWI_Init(void) ATTR_ALWAYS_INLINE;
  78                         static inline void TWI_Init(void)
  79                         {
  80                                 TWCR |=  (1 << TWEN);
  81                         }
  82
  83                         /** Turns off the TWI driver hardware. If this is called, any further TWI operations will require a call to
  84                          *  \ref TWI_Init() before the TWI can be used again.
  85                          */
  86                         static inline void TWI_ShutDown(void) ATTR_ALWAYS_INLINE;
  87                         static inline void TWI_ShutDown(void)
  88                         {
  89                                 TWCR &= ~(1 << TWEN);
  90                         }
  91
  92                         /** Sends a TWI STOP onto the TWI bus, terminating communication with the currently addressed device. */
  93                         static inline void TWI_StopTransmission(void) ATTR_ALWAYS_INLINE;
  94                         static inline void TWI_StopTransmission(void)
  95                         {
  96                                 TWCR = ((1 << TWINT) | (1 << TWSTO) | (1 << TWEN));
  97                         }
  98
  99                         /** Sends a byte to the currently addressed device on the TWI bus.
 100                          *
 101                          *  \param[in] Byte  Byte to send to the currently addressed device
 102                          *
 103                          *  \return Boolean true if the recipient ACKed the byte, false otherwise
 104                          */
 105                         static inline bool TWI_SendByte(const uint8_t Byte)
 106                         {
 107                                 TWDR = Byte;
 108                                 TWCR = ((1 << TWINT) | (1 << TWEN));
 109                                 while (!(TWCR & (1 << TWINT)));
 110
 111                                 return ((TWSR & TW_STATUS_MASK) == TW_MT_DATA_ACK);
 112                         }
 113
 114                         /** Receives a byte from the currently addressed device on the TWI bus.
 115                          *
 116                          *  \param[in] Byte      Location where the read byte is to be stored
 117                          *  \param[in] LastByte  Indicates if the byte should be ACKed if false, NAKed if true
 118                          *
 119                          *  \return Boolean true if the byte reception successfully completed, false otherwise
 120                          */
 121                         static inline bool TWI_ReceiveByte(uint8_t* const Byte,
 122                                                            const bool LastByte)
 123                         {
 124                                 uint8_t TWCRMask = ((1 << TWINT) | (1 << TWEN));
 125
 126                                 if (!(LastByte))
 127                                   TWCRMask |= (1 << TWEA);
 128
 129                                 TWCR = TWCRMask;
 130                                 while (!(TWCR & (1 << TWINT)));
 131                                 *Byte = TWDR;
 132
 133                                 return ((TWSR & TW_STATUS_MASK) == TW_MR_DATA_ACK);
 134                         }
 135
 136                 /* Function Prototypes: */
 137                         /** Begins a master mode TWI bus communication with the given slave device address.
 138                          *
 139                          *  \param[in] SlaveAddress  Address of the slave TWI device to communicate with
 140                          *  \param[in] TimeoutMS     Timeout period within which the slave must respond, in milliseconds
 141                          *
 142                          *  \return Boolean true if the device is ready for data, false otherwise
 143                          */
 144                         bool TWI_StartTransmission(const uint8_t SlaveAddress,
 145                                                    const uint8_t TimeoutMS);
 146
 147         /* Disable C linkage for C++ Compilers: */
 148                 #if defined(__cplusplus)
 149                         }
 150                 #endif
 151
 152 #endif
 153
 154 /** @} */