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  *      // Initialize the TWI driver before first use at 200KHz
  56  *      TWI_Init(TWI_BIT_PRESCALE_1, TWI_BITLENGTH_FROM_FREQ(1, 200000));
  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) == TWI_ERROR_NoError)
  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) == TWI_ERROR_NoError)
  73  *      {
  74  *          TWI_SendByte(0xDC);
  75  *          TWI_StopTransmission();
  76  *
  77  *          if (TWI_StartTransmission(0xA0 | TWI_ADDRESS_READ, 10) == TWI_ERROR_NoError)
  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  *      // Initialize the TWI driver before first use at 200KHz
  95  *      TWI_Init(TWI_BIT_PRESCALE_1, TWI_BITLENGTH_FROM_FREQ(1, 200000));
  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         0x01
 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        0x00
 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                         /** Calculates the length of each bit on the TWI bus for a given target frequency. This may be used with
 171                          *  the \ref TWI_Init() function to convert a bus frequency to a number of clocks for the \c BitLength
 172                          *  parameter.
 173                          *
 174                          *  \param[in] Prescale   Prescaler set on the TWI bus.
 175                          *  \param[in] Frequency  Desired TWI bus frequency in Hz.
 176                          *
 177                          *  \return Bit length in clocks for the given TWI bus frequency at the given prescaler value.
 178                          */
 179                         #define TWI_BITLENGTH_FROM_FREQ(Prescale, Frequency) ((((F_CPU / (Prescale)) / (Frequency)) - 16) / 2)
 180
 181                 /* Enums: */
 182                         /** Enum for the possible return codes of the TWI transfer start routine and other dependant TWI functions. */
 183                         enum TWI_ErrorCodes_t
 184                         {
 185                                 TWI_ERROR_NoError              = 0, /**< Indicates that the command completed successfully. */
 186                                 TWI_ERROR_BusFault             = 1, /**< A TWI bus fault occurred while attempting to capture the bus. */
 187                                 TWI_ERROR_BusCaptureTimeout    = 2, /**< A timeout occurred whilst waiting for the bus to be ready. */
 188                                 TWI_ERROR_SlaveResponseTimeout = 3, /**< No ACK received at the nominated slave address within the timeout period. */
 189                                 TWI_ERROR_SlaveNotReady        = 4, /**< Slave NAKed the TWI bus START condition. */
 190                                 TWI_ERROR_SlaveNAK             = 5, /**< Slave NAKed whilst attempting to send data to the device. */
 191                         };
 192
 193                 /* Inline Functions: */
 194                         /** Initializes the TWI hardware into master mode, ready for data transmission and reception. This must be
 195                          *  before any other TWI operations.
 196                          *
 197                          *  The generated SCL frequency will be according to the formula <pre>F_CPU / (16 + 2 * BitLength + 4 ^ Prescale)</pre>.
 198                          *
 199                          *  \note The value of the \c BitLength parameter should not be set below 10 or invalid bus conditions may
 200                          *        occur, as indicated in the AVR8 microcontroller datasheet.
 201                          *
 202                          *  \param[in] Prescale   Prescaler to use when determining the bus frequency, a \c TWI_BIT_PRESCALE_* value.
 203                          *  \param[in] BitLength  Length of the bits sent on the bus.
 204                          */
 205                         static inline void TWI_Init(const uint8_t Prescale, const uint8_t BitLength) ATTR_ALWAYS_INLINE;
 206                         static inline void TWI_Init(const uint8_t Prescale, const uint8_t BitLength)
 207                         {
 208                                 TWCR |= (1 << TWEN);
 209                                 TWSR  = Prescale;
 210                                 TWBR  = BitLength;
 211                         }
 212
 213                         /** Turns off the TWI driver hardware. If this is called, any further TWI operations will require a call to
 214                          *  \ref TWI_Init() before the TWI can be used again.
 215                          */
 216                         static inline void TWI_Disable(void) ATTR_ALWAYS_INLINE;
 217                         static inline void TWI_Disable(void)
 218                         {
 219                                 TWCR &= ~(1 << TWEN);
 220                         }
 221
 222                         /** Sends a TWI STOP onto the TWI bus, terminating communication with the currently addressed device. */
 223                         static inline void TWI_StopTransmission(void) ATTR_ALWAYS_INLINE;
 224                         static inline void TWI_StopTransmission(void)
 225                         {
 226                                 TWCR = ((1 << TWINT) | (1 << TWSTO) | (1 << TWEN));
 227                         }
 228
 229                 /* Function Prototypes: */
 230                         /** Begins a master mode TWI bus communication with the given slave device address.
 231                          *
 232                          *  \param[in] SlaveAddress  Address of the slave TWI device to communicate with.
 233                          *  \param[in] TimeoutMS     Timeout period within which the slave must respond, in milliseconds.
 234                          *
 235                          *  \return A value from the \ref TWI_ErrorCodes_t enum.
 236                          */
 237                         uint8_t TWI_StartTransmission(const uint8_t SlaveAddress,
 238                                                       const uint8_t TimeoutMS);
 239
 240                         /** Sends a byte to the currently addressed device on the TWI bus.
 241                          *
 242                          *  \param[in] Byte  Byte to send to the currently addressed device
 243                          *
 244                          *  \return Boolean \c true if the recipient ACKed the byte, \c false otherwise
 245                          */
 246                         bool TWI_SendByte(const uint8_t Byte);
 247
 248                         /** Receives a byte from the currently addressed device on the TWI bus.
 249                          *
 250                          *  \param[in] Byte      Location where the read byte is to be stored.
 251                          *  \param[in] LastByte  Indicates if the byte should be ACKed if false, NAKed if true.
 252                          *
 253                          *  \return Boolean \c true if the byte reception successfully completed, \c false otherwise.
 254                          */
 255                         bool TWI_ReceiveByte(uint8_t* const Byte,
 256                                              const bool LastByte) ATTR_NON_NULL_PTR_ARG(1);
 257                         bool TWI_ReceiveByte(uint8_t* const Byte,
 258                                              const bool LastByte);
 259
 260                         /** High level function to perform a complete packet transfer over the TWI bus to the specified
 261                          *  device.
 262                          *
 263                          *  \param[in] SlaveAddress        Base address of the TWI slave device to communicate with.
 264                          *  \param[in] TimeoutMS           Timeout for bus capture and slave START ACK, in milliseconds.
 265                          *  \param[in] InternalAddress     Pointer to a location where the internal slave read start address is stored.
 266                          *  \param[in] InternalAddressLen  Size of the internal device address, in bytes.
 267                          *  \param[in] Buffer              Pointer to a buffer where the read packet data is to be stored.
 268                          *  \param[in] Length              Size of the packet to read, in bytes.
 269                          *
 270                          *  \return A value from the \ref TWI_ErrorCodes_t enum.
 271                          */
 272                         uint8_t TWI_ReadPacket(const uint8_t SlaveAddress,
 273                                                const uint8_t TimeoutMS,
 274                                                const uint8_t* InternalAddress,
 275                                                uint8_t InternalAddressLen,
 276                                                uint8_t* Buffer,
 277                                                uint8_t Length) ATTR_NON_NULL_PTR_ARG(3);
 278
 279                         /** High level function to perform a complete packet transfer over the TWI bus from the specified
 280                          *  device.
 281                          *
 282                          *  \param[in] SlaveAddress        Base address of the TWI slave device to communicate with
 283                          *  \param[in] TimeoutMS           Timeout for bus capture and slave START ACK, in milliseconds
 284                          *  \param[in] InternalAddress     Pointer to a location where the internal slave write start address is stored
 285                          *  \param[in] InternalAddressLen  Size of the internal device address, in bytes
 286                          *  \param[in] Buffer              Pointer to a buffer where the packet data to send is stored
 287                          *  \param[in] Length              Size of the packet to send, in bytes
 288                          *
 289                          *  \return A value from the \ref TWI_ErrorCodes_t enum.
 290                          */
 291                         uint8_t TWI_WritePacket(const uint8_t SlaveAddress,
 292                                                 const uint8_t TimeoutMS,
 293                                                 const uint8_t* InternalAddress,
 294                                                 uint8_t InternalAddressLen,
 295                                                 const uint8_t* Buffer,
 296                                                 uint8_t Length) ATTR_NON_NULL_PTR_ARG(3);
 297
 298         /* Disable C linkage for C++ Compilers: */
 299                 #if defined(__cplusplus)
 300                         }
 301                 #endif
 302
 303 #endif
 304
 305 /** @} */
 306