LUFA/Drivers/Peripheral/AVR8/TWI_AVR8.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(TWI_BIT_PRESCALE_1, 10);
  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(TWI_BIT_PRESCALE_1, 10);
  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                         /** Bit length prescaler for \ref TWI_Init(). This mask multiplies the TWI bit length prescaler by 1. */
 159                         #define TWI_BIT_PRESCALE_1       ((0 << TWPS1) | (0 << TWPS0))
 160
 161                         /** Bit length prescaler for \ref TWI_Init(). This mask multiplies the TWI bit length prescaler by 4. */
 162                         #define TWI_BIT_PRESCALE_4       ((0 << TWPS1) | (1 << TWPS0))
 163
 164                         /** Bit length prescaler for \ref TWI_Init(). This mask multiplies the TWI bit length prescaler by 16. */
 165                         #define TWI_BIT_PRESCALE_16      ((1 << TWPS1) | (0 << TWPS0))
 166
 167                         /** Bit length prescaler for \ref TWI_Init(). This mask multiplies the TWI bit length prescaler by 64. */
 168                         #define TWI_BIT_PRESCALE_64      ((1 << TWPS1) | (1 << TWPS0))
 169
 170                 /* Enums: */
 171                         /** Enum for the possible return codes of the TWI transfer start routine and other dependant TWI functions. */
 172                         enum TWI_ErrorCodes_t
 173                         {
 174                                 TWI_ERROR_NoError              = 0, /**< Indicates that the command completed sucessfully. */
 175                                 TWI_ERROR_BusFault             = 1, /**< A TWI bus fault occurred while attempting to capture the bus. */
 176                                 TWI_ERROR_BusCaptureTimeout    = 2, /**< A timeout occurred whilst waiting for the bus to be ready. */
 177                                 TWI_ERROR_SlaveResponseTimeout = 3, /**< No ACK received at the nominated slave address within the timeout period. */
 178                                 TWI_ERROR_SlaveNotReady        = 4, /**< Slave NAKed the TWI bus START condition. */
 179                                 TWI_ERROR_SlaveNAK             = 5, /**< Slave NAKed whilst attempting to send data to the device. */
 180                         };
 181
 182                 /* Inline Functions: */
 183                         /** Initialises the TWI hardware into master mode, ready for data transmission and reception. This must be
 184                          *  before any other TWI operations.
 185                          *
 186                          *  The generated SCL frequency will be according to the formula <pre>F_CPU / (16 + 2 * BitLength + 4 ^ Prescale)</pre>.
 187                          *
 188                          *  \note The value of the \c BitLength parameter should not be set below 10 or invalid bus conditions may
 189                          *        occur, as indicated in the AVR8 microcontroller datasheet.
 190                          *
 191                          *  \param[in] Prescale   Prescaler to use when determining the bus frequency, a \c TWI_BIT_PRESCALE_* value.
 192                          *  \param[in] BitLength  Length of the bits sent on the bus.
 193                          */
 194                         static inline void TWI_Init(const uint8_t Prescale, const uint8_t BitLength) ATTR_ALWAYS_INLINE;
 195                         static inline void TWI_Init(const uint8_t Prescale, const uint8_t BitLength)
 196                         {
 197                                 TWCR |= (1 << TWEN);
 198                                 TWSR  = Prescale;
 199                                 TWBR  = BitLength;
 200                         }
 201
 202                         /** Turns off the TWI driver hardware. If this is called, any further TWI operations will require a call to
 203                          *  \ref TWI_Init() before the TWI can be used again.
 204                          */
 205                         static inline void TWI_Disable(void) ATTR_ALWAYS_INLINE;
 206                         static inline void TWI_Disable(void)
 207                         {
 208                                 TWCR &= ~(1 << TWEN);
 209                         }
 210
 211                         /** Sends a TWI STOP onto the TWI bus, terminating communication with the currently addressed device. */
 212                         static inline void TWI_StopTransmission(void) ATTR_ALWAYS_INLINE;
 213                         static inline void TWI_StopTransmission(void)
 214                         {
 215                                 TWCR = ((1 << TWINT) | (1 << TWSTO) | (1 << TWEN));
 216                         }
 217
 218                         /** Sends a byte to the currently addressed device on the TWI bus.
 219                          *
 220                          *  \param[in] Byte  Byte to send to the currently addressed device
 221                          *
 222                          *  \return Boolean \c true if the recipient ACKed the byte, \c false otherwise
 223                          */
 224                         static inline bool TWI_SendByte(const uint8_t Byte)
 225                         {
 226                                 TWDR = Byte;
 227                                 TWCR = ((1 << TWINT) | (1 << TWEN));
 228                                 while (!(TWCR & (1 << TWINT)));
 229
 230                                 return ((TWSR & TW_STATUS_MASK) == TW_MT_DATA_ACK);
 231                         }
 232
 233                         /** Receives a byte from the currently addressed device on the TWI bus.
 234                          *
 235                          *  \param[in] Byte      Location where the read byte is to be stored
 236                          *  \param[in] LastByte  Indicates if the byte should be ACKed if false, NAKed if true
 237                          *
 238                          *  \return Boolean \c true if the byte reception successfully completed, \c false otherwise
 239                          */
 240                         static inline uint8_t TWI_ReceiveByte(uint8_t* const Byte,
 241                                                               const bool LastByte)
 242                         {
 243                                 uint8_t TWCRMask = ((1 << TWINT) | (1 << TWEN));
 244
 245                                 if (!(LastByte))
 246                                   TWCRMask |= (1 << TWEA);
 247
 248                                 TWCR = TWCRMask;
 249                                 while (!(TWCR & (1 << TWINT)));
 250                                 *Byte = TWDR;
 251
 252                                 return ((TWSR & TW_STATUS_MASK) == TW_MR_DATA_ACK);
 253                         }
 254
 255                 /* Function Prototypes: */
 256                         /** Begins a master mode TWI bus communication with the given slave device address.
 257                          *
 258                          *  \param[in] SlaveAddress  Address of the slave TWI device to communicate with
 259                          *  \param[in] TimeoutMS     Timeout period within which the slave must respond, in milliseconds
 260                          *
 261                          *  \return A value from the \ref TWI_ErrorCodes_t enum
 262                          */
 263                         uint8_t TWI_StartTransmission(const uint8_t SlaveAddress,
 264                                                       const uint8_t TimeoutMS);
 265
 266                         /** High level function to perform a complete packet transfer over the TWI bus to the specified
 267                          *  device.
 268                          *
 269                          *  \param[in] SlaveAddress        Base address of the TWI slave device to communicate with
 270                          *  \param[in] TimeoutMS           Timeout for bus capture and slave START ACK, in milliseconds
 271                          *  \param[in] InternalAddress     Pointer to a location where the internal slave read start address is stored
 272                          *  \param[in] InternalAddressLen  Size of the internal device address, in bytes
 273                          *  \param[in] Buffer              Pointer to a buffer where the read packet data is to be stored
 274                          *  \param[in] Length              Size of the packet to read, in bytes
 275                          */
 276                         uint8_t TWI_ReadPacket(const uint8_t SlaveAddress,
 277                                                const uint8_t TimeoutMS,
 278                                                const uint8_t* InternalAddress,
 279                                                uint8_t InternalAddressLen,
 280                                                uint8_t* Buffer,
 281                                                uint8_t Length);
 282
 283                         /** High level function to perform a complete packet transfer over the TWI bus from the specified
 284                          *  device.
 285                          *
 286                          *  \param[in] SlaveAddress        Base address of the TWI slave device to communicate with
 287                          *  \param[in] TimeoutMS           Timeout for bus capture and slave START ACK, in milliseconds
 288                          *  \param[in] InternalAddress     Pointer to a location where the internal slave write start address is stored
 289                          *  \param[in] InternalAddressLen  Size of the internal device address, in bytes
 290                          *  \param[in] Buffer              Pointer to a buffer where the packet data to send is stored
 291                          *  \param[in] Length              Size of the packet to send, in bytes
 292                          */
 293                         uint8_t TWI_WritePacket(const uint8_t SlaveAddress,
 294                                                 const uint8_t TimeoutMS,
 295                                                 const uint8_t* InternalAddress,
 296                                                 uint8_t InternalAddressLen,
 297                                                 const uint8_t* Buffer,
 298                                                 uint8_t Length);
 299
 300         /* Disable C linkage for C++ Compilers: */
 301                 #if defined(__cplusplus)
 302                         }
 303                 #endif
 304
 305 #endif
 306
 307 /** @} */
 308