LUFA/Drivers/Peripheral/AVR8/TWI.h

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2011.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6            www.lufa-lib.org
   7 */
   8
   9 /*
  10   Copyright 2011  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 (AVR8)
  33  *
  34  *  On-chip TWI driver for the 8-bit AVR microcontrollers.
  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_AVR8 TWI Peripheral Driver (AVR8)
  42  *
  43  *  \section Sec_ModDescription Module Description
  44  *  Master mode TWI driver for the 8-bit AVR microcontrollers which contain a hardware TWI module.
  45  *
  46  *  \note This file should not be included directly. It is automatically included as needed by the TWI driver
  47  *        dispatch header located in LUFA/Drivers/Peripheral/TWI.h.
  48  *
  49  *  \section Sec_ExampleUsage Example Usage
  50  *  The following snippet is an example of how this module may be used within a typical
  51  *  application.
  52  *
  53  *  <b>Low Level API Example:</b>
  54  *  \code
  55  *      // Initialise the TWI driver before first use
  56  *      TWI_Init();
  57  *
  58  *      // Start a write session to device at device address 0xA0, internal address 0xDC with a 10ms timeout
  59  *      if (TWI_StartTransmission(0xA0 | TWI_ADDRESS_WRITE, 10))
  60  *      {
  61  *          TWI_SendByte(0xDC);
  62  *
  63  *          TWI_SendByte(0x01);
  64  *          TWI_SendByte(0x02);
  65  *          TWI_SendByte(0x03);
  66  *
  67  *          // Must stop transmission afterwards to release the bus
  68  *          TWI_StopTransmission();
  69  *      }
  70  *
  71  *      // Start a read session to device at address 0xA0, internal address 0xDC with a 10ms timeout
  72  *      if (TWI_StartTransmission(0xA0 | TWI_ADDRESS_WRITE, 10))
  73  *      {
  74  *          TWI_SendByte(0xDC);
  75  *          TWI_StopTransmission();
  76  *
  77  *          if (TWI_StartTransmission(0xA0 | TWI_ADDRESS_READ, 10))
  78  *          {
  79  *              uint8_t Byte1, Byte2, Byte3;
  80  *
  81  *              // Read three bytes, acknowledge after the third byte is received
  82  *              TWI_ReceiveByte(&Byte1, false);
  83  *              TWI_ReceiveByte(&Byte2, false);
  84  *              TWI_ReceiveByte(&Byte3, true);
  85  *
  86  *              // Must stop transmission afterwards to release the bus
  87  *              TWI_StopTransmission();
  88  *          }
  89  *      }
  90  *  \endcode
  91  *
  92  *  <b>High Level API Example:</b>
  93  *  \code
  94  *      // Initialise the TWI driver before first use
  95  *      TWI_Init();
  96  *
  97  *      // Start a write session to device at device address 0xA0, internal address 0xDC with a 10ms timeout
  98  *      uint8_t InternalWriteAddress = 0xDC;
  99  *      uint8_t WritePacket[3] = {0x01, 0x02, 0x03};
 100  *
 101  *      TWI_WritePacket(0xA0, 10, &InternalWriteAddress, sizeof(InternalWriteAddress),
 102  *                      &WritePacket, sizeof(WritePacket);
 103  *
 104  *      // Start a read session to device at address 0xA0, internal address 0xDC with a 10ms timeout
 105  *      uint8_t InternalReadAddress = 0xDC;
 106  *      uint8_t ReadPacket[3];
 107  *
 108  *      TWI_ReadPacket(0xA0, 10, &InternalReadAddress, sizeof(InternalReadAddress),
 109  *                     &ReadPacket, sizeof(ReadPacket);
 110  *  \endcode
 111  *
 112  *  @{
 113  */
 114
 115 #ifndef __TWI_AVR8_H__
 116 #define __TWI_AVR8_H__
 117
 118         /* Includes: */
 119                 #include "../../../Common/Common.h"
 120
 121                 #include <stdio.h>
 122                 #include <util/twi.h>
 123
 124         /* Enable C linkage for C++ Compilers: */
 125                 #if defined(__cplusplus)
 126                         extern "C" {
 127                 #endif
 128
 129         /* Preprocessor Checks: */
 130                 #if !defined(__INCLUDE_FROM_TWI_H) && !defined(__INCLUDE_FROM_TWI_C)
 131                         #error Do not include this file directly. Include LUFA/Drivers/Peripheral/TWI.h instead.
 132                 #endif
 133
 134                 #if !(defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB646__) || \
 135                       defined(__AVR_AT90USB1287__) || defined(__AVR_AT90USB647__) || \
 136                           defined(__AVR_ATmega16U4__)  || defined(__AVR_ATmega32U4__) || \
 137                           defined(__AVR_ATmega32U6__))
 138                         #error The TWI peripheral driver is not currently available for your selected microcontroller model.
 139                 #endif
 140
 141         /* Public Interface - May be used in end-application: */
 142                 /* Macros: */
 143                         /** TWI slave device address mask for a read session. Mask with a slave device base address to obtain
 144                          *  the correct TWI bus address for the slave device when reading data from it.
 145                          */
 146                         #define TWI_ADDRESS_READ         0x00
 147
 148                         /** TWI slave device address mask for a write session. Mask with a slave device base address to obtain
 149                          *  the correct TWI bus address for the slave device when writing data to it.
 150                          */
 151                         #define TWI_ADDRESS_WRITE        0x01
 152
 153                         /** Mask to retrieve the base address for a TWI device, which can then be ORed with \ref TWI_ADDRESS_READ
 154                          *  or \ref TWI_ADDRESS_WRITE to obtain the device's read and write address respectively.
 155                          */
 156                         #define TWI_DEVICE_ADDRESS_MASK  0xFE
 157
 158                 /* Enums: */
 159                         /** Enum for the possible return codes of the TWI transfer start routine and other dependant TWI functions. */
 160                         enum TWI_ErrorCodes_t
 161                         {
 162                                 TWI_ERROR_NoError              = 0, /**< Indicates that the command completed sucessfully. */
 163                                 TWI_ERROR_BusFault             = 1, /**< A TWI bus fault occurred while attempting to capture the bus. */
 164                                 TWI_ERROR_BusCaptureTimeout    = 2, /**< A timeout occurred whilst waiting for the bus to be ready. */
 165                                 TWI_ERROR_SlaveResponseTimeout = 3, /**< No ACK received at the nominated slave address within the timeout period. */
 166                                 TWI_ERROR_SlaveNotReady        = 4, /**< Slave NAKed the TWI bus START condition. */
 167                                 TWI_ERROR_SlaveNAK             = 5, /**< Slave NAKed whilst attempting to send data to the device. */
 168                         };
 169
 170                 /* Inline Functions: */
 171                         /** Initialises the TWI hardware into master mode, ready for data transmission and reception. This must be
 172                          *  before any other TWI operations.
 173                          */
 174                         static inline void TWI_Init(void) ATTR_ALWAYS_INLINE;
 175                         static inline void TWI_Init(void)
 176                         {
 177                                 TWCR |=  (1 << TWEN);
 178                         }
 179
 180                         /** Turns off the TWI driver hardware. If this is called, any further TWI operations will require a call to
 181                          *  \ref TWI_Init() before the TWI can be used again.
 182                          */
 183                         static inline void TWI_Disable(void) ATTR_ALWAYS_INLINE;
 184                         static inline void TWI_Disable(void)
 185                         {
 186                                 TWCR &= ~(1 << TWEN);
 187                         }
 188
 189                         /** Sends a TWI STOP onto the TWI bus, terminating communication with the currently addressed device. */
 190                         static inline void TWI_StopTransmission(void) ATTR_ALWAYS_INLINE;
 191                         static inline void TWI_StopTransmission(void)
 192                         {
 193                                 TWCR = ((1 << TWINT) | (1 << TWSTO) | (1 << TWEN));
 194                         }
 195
 196                         /** Sends a byte to the currently addressed device on the TWI bus.
 197                          *
 198                          *  \param[in] Byte  Byte to send to the currently addressed device
 199                          *
 200                          *  \return Boolean \c true if the recipient ACKed the byte, \c false otherwise
 201                          */
 202                         static inline bool TWI_SendByte(const uint8_t Byte)
 203                         {
 204                                 TWDR = Byte;
 205                                 TWCR = ((1 << TWINT) | (1 << TWEN));
 206                                 while (!(TWCR & (1 << TWINT)));
 207
 208                                 return ((TWSR & TW_STATUS_MASK) == TW_MT_DATA_ACK);
 209                         }
 210
 211                         /** Receives a byte from the currently addressed device on the TWI bus.
 212                          *
 213                          *  \param[in] Byte      Location where the read byte is to be stored
 214                          *  \param[in] LastByte  Indicates if the byte should be ACKed if false, NAKed if true
 215                          *
 216                          *  \return Boolean \c true if the byte reception successfully completed, \c false otherwise
 217                          */
 218                         static inline uint8_t TWI_ReceiveByte(uint8_t* const Byte,
 219                                                               const bool LastByte)
 220                         {
 221                                 uint8_t TWCRMask = ((1 << TWINT) | (1 << TWEN));
 222
 223                                 if (!(LastByte))
 224                                   TWCRMask |= (1 << TWEA);
 225
 226                                 TWCR = TWCRMask;
 227                                 while (!(TWCR & (1 << TWINT)));
 228                                 *Byte = TWDR;
 229
 230                                 return ((TWSR & TW_STATUS_MASK) == TW_MR_DATA_ACK);
 231                         }
 232
 233                 /* Function Prototypes: */
 234                         /** Begins a master mode TWI bus communication with the given slave device address.
 235                          *
 236                          *  \param[in] SlaveAddress  Address of the slave TWI device to communicate with
 237                          *  \param[in] TimeoutMS     Timeout period within which the slave must respond, in milliseconds
 238                          *
 239                          *  \return A value from the \ref TWI_ErrorCodes_t enum
 240                          */
 241                         uint8_t TWI_StartTransmission(const uint8_t SlaveAddress,
 242                                                       const uint8_t TimeoutMS);
 243
 244                         /** High level function to perform a complete packet transfer over the TWI bus to the specified
 245                          *  device.
 246                          *
 247                          *  \param[in] SlaveAddress        Base address of the TWI slave device to communicate with
 248                          *  \param[in] TimeoutMS           Timeout for bus capture and slave START ACK, in milliseconds
 249                          *  \param[in] InternalAddress     Pointer to a location where the internal slave read start address is stored
 250                          *  \param[in] InternalAddressLen  Size of the internal device address, in bytes
 251                          *  \param[in] Buffer              Pointer to a buffer where the read packet data is to be stored
 252                          *  \param[in] Length              Size of the packet to read, in bytes
 253                          */
 254                         uint8_t TWI_ReadPacket(const uint8_t SlaveAddress,
 255                                                const uint8_t TimeoutMS,
 256                                                const uint8_t* InternalAddress,
 257                                                uint8_t InternalAddressLen,
 258                                                uint8_t* Buffer,
 259                                                uint8_t Length);
 260
 261                         /** High level function to perform a complete packet transfer over the TWI bus from the specified
 262                          *  device.
 263                          *
 264                          *  \param[in] SlaveAddress        Base address of the TWI slave device to communicate with
 265                          *  \param[in] TimeoutMS           Timeout for bus capture and slave START ACK, in milliseconds
 266                          *  \param[in] InternalAddress     Pointer to a location where the internal slave write start address is stored
 267                          *  \param[in] InternalAddressLen  Size of the internal device address, in bytes
 268                          *  \param[in] Buffer              Pointer to a buffer where the packet data to send is stored
 269                          *  \param[in] Length              Size of the packet to send, in bytes
 270                          */
 271                         uint8_t TWI_WritePacket(const uint8_t SlaveAddress,
 272                                                 const uint8_t TimeoutMS,
 273                                                 const uint8_t* InternalAddress,
 274                                                 uint8_t InternalAddressLen,
 275                                                 const uint8_t* Buffer,
 276                                                 uint8_t Length);
 277
 278         /* Disable C linkage for C++ Compilers: */
 279                 #if defined(__cplusplus)
 280                         }
 281                 #endif
 282
 283 #endif
 284
 285 /** @} */
 286