LUFA/Drivers/Peripheral/SPI.h

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2010.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6            www.lufa-lib.org
   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 Master include file for the SPI peripheral driver.
  33  *
  34  *  Hardware SPI subsystem driver for the supported USB AVRs models.
  35  */
  36
  37 /** \ingroup Group_PeripheralDrivers
  38  *  @defgroup Group_SPI SPI Driver - LUFA/Drivers/Peripheral/SPI.h
  39  *
  40  *  \section Sec_Dependencies Module Source Dependencies
  41  *  The following files must be built with any user project that uses this module:
  42  *    - None
  43  *
  44  *  \section Module Description
  45  *  Driver for the hardware SPI port available on most AVR models. This module provides
  46  *  an easy to use driver for the setup of and transfer of data over the AVR's SPI port.
  47  *
  48  *  <b>Example Usage:</b>
  49  *  \code
  50  *      // Initialise the SPI driver before first use
  51  *      SPI_Init(SPI_SPEED_FCPU_DIV_2 | SPI_ORDER_MSB_FIRST | SPI_SCK_LEAD_FALLING |
  52  *               SPI_SAMPLE_TRAILING | SPI_MODE_MASTER);
  53  *
  54  *      // Send several bytes, ignoring the returned data
  55  *      SPI_SendByte(0x01);
  56  *      SPI_SendByte(0x02);
  57  *      SPI_SendByte(0x03);
  58  *
  59  *      // Receive several bytes, sending a dummy 0x00 byte each time
  60  *      uint8_t Byte1 = SPI_ReceiveByte();
  61  *      uint8_t Byte2 = SPI_ReceiveByte();
  62  *      uint8_t Byte3 = SPI_ReceiveByte();
  63  *
  64  *      // Send a byte, and store the received byte from the same transaction
  65  *      uint8_t ResponseByte = SPI_TransferByte(0xDC);
  66  *  \endcode
  67  *
  68  *  @{
  69  */
  70
  71 #ifndef __SPI_H__
  72 #define __SPI_H__
  73
  74         /* Includes: */
  75                 #include <stdbool.h>
  76
  77         /* Enable C linkage for C++ Compilers: */
  78                 #if defined(__cplusplus)
  79                         extern "C" {
  80                 #endif
  81
  82         /* Private Interface - For use in library only: */
  83         #if !defined(__DOXYGEN__)
  84                 /* Macros: */
  85                         #define SPI_USE_DOUBLESPEED            (1 << SPE)
  86         #endif
  87
  88         /* Public Interface - May be used in end-application: */
  89                 /* Macros: */
  90                         /** \name SPI Prescaler Configuration Masks */
  91                         //@{
  92                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 2. */
  93                         #define SPI_SPEED_FCPU_DIV_2           SPI_USE_DOUBLESPEED
  94
  95                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 4. */
  96                         #define SPI_SPEED_FCPU_DIV_4           0
  97
  98                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 8. */
  99                         #define SPI_SPEED_FCPU_DIV_8           (SPI_USE_DOUBLESPEED | (1 << SPR0))
 100
 101                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 16. */
 102                         #define SPI_SPEED_FCPU_DIV_16          (1 << SPR0)
 103
 104                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 32. */
 105                         #define SPI_SPEED_FCPU_DIV_32          (SPI_USE_DOUBLESPEED | (1 << SPR1))
 106
 107                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 64. */
 108                         #define SPI_SPEED_FCPU_DIV_64          (SPI_USE_DOUBLESPEED | (1 << SPR1) | (1 << SPR0))
 109
 110                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 128. */
 111                         #define SPI_SPEED_FCPU_DIV_128         ((1 << SPR1) | (1 << SPR0))
 112                         //@}
 113
 114                         /** \name SPI SCK Polarity Configuration Masks */
 115                         //@{
 116                         /** SPI clock polarity mask for SPI_Init(). Indicates that the SCK should lead on the rising edge. */
 117                         #define SPI_SCK_LEAD_RISING            (0 << CPOL)
 118
 119                         /** SPI clock polarity mask for SPI_Init(). Indicates that the SCK should lead on the falling edge. */
 120                         #define SPI_SCK_LEAD_FALLING           (1 << CPOL)
 121                         //@}
 122
 123                         /** \name SPI Sample Edge Configuration Masks */
 124                         //@{
 125                         /** SPI data sample mode mask for SPI_Init(). Indicates that the data should sampled on the leading edge. */
 126                         #define SPI_SAMPLE_LEADING             (0 << CPHA)
 127
 128                         /** SPI data sample mode mask for SPI_Init(). Indicates that the data should be sampled on the trailing edge. */
 129                         #define SPI_SAMPLE_TRAILING            (1 << CPHA)
 130                         //@}
 131
 132                         /** \name SPI Data Ordering Configuration Masks */
 133                         //@{
 134                         /** SPI data order mask for SPI_Init(). Indicates that data should be shifted out MSB first. */
 135                         #define SPI_ORDER_MSB_FIRST            (0 << DORD)
 136
 137                         /** SPI data order mask for SPI_Init(). Indicates that data should be shifted out MSB first. */
 138                         #define SPI_ORDER_LSB_FIRST            (1 << DORD)
 139                         //@}
 140
 141                         /** \name SPI Mode Configuration Masks */
 142                         //@{
 143                         /** SPI mode mask for SPI_Init(). Indicates that the SPI interface should be initialized into slave mode. */
 144                         #define SPI_MODE_SLAVE                 (0 << MSTR)
 145
 146                         /** SPI mode mask for SPI_Init(). Indicates that the SPI interface should be initialized into master mode. */
 147                         #define SPI_MODE_MASTER                (1 << MSTR)
 148                         //@}
 149
 150                 /* Inline Functions: */
 151                         /** Initialises the SPI subsystem, ready for transfers. Must be called before calling any other
 152                          *  SPI routines.
 153                          *
 154                          *  \param[in] SPIOptions  SPI Options, a mask consisting of one of each of the SPI_SPEED_*,
 155                          *                         SPI_SCK_*, SPI_SAMPLE_*, SPI_ORDER_* and SPI_MODE_* masks.
 156                          */
 157                         static inline void SPI_Init(const uint8_t SPIOptions)
 158                         {
 159                                 DDRB  |=  ((1 << 1) | (1 << 2));
 160                                 DDRB  &= ~((1 << 0) | (1 << 3));
 161                                 PORTB |=  ((1 << 0) | (1 << 3));
 162
 163                                 SPCR   = ((1 << SPE) | SPIOptions);
 164
 165                                 if (SPIOptions & SPI_USE_DOUBLESPEED)
 166                                   SPSR |= (1 << SPI2X);
 167                                 else
 168                                   SPSR &= ~(1 << SPI2X);
 169                         }
 170
 171                         /** Turns off the SPI driver, disabling and returning used hardware to their default configuration. */
 172                         static inline void SPI_ShutDown(void)
 173                         {
 174                                 DDRB  &= ~((1 << 1) | (1 << 2));
 175                                 PORTB &= ~((1 << 0) | (1 << 3));
 176
 177                                 SPCR   = 0;
 178                                 SPSR   = 0;
 179                         }
 180
 181                         /** Sends and receives a byte through the SPI interface, blocking until the transfer is complete.
 182                          *
 183                          *  \param[in] Byte  Byte to send through the SPI interface.
 184                          *
 185                          *  \return Response byte from the attached SPI device.
 186                          */
 187                         static inline uint8_t SPI_TransferByte(const uint8_t Byte) ATTR_ALWAYS_INLINE;
 188                         static inline uint8_t SPI_TransferByte(const uint8_t Byte)
 189                         {
 190                                 SPDR = Byte;
 191                                 while (!(SPSR & (1 << SPIF)));
 192                                 return SPDR;
 193                         }
 194
 195                         /** Sends a byte through the SPI interface, blocking until the transfer is complete. The response
 196                          *  byte sent to from the attached SPI device is ignored.
 197                          *
 198                          *  \param[in] Byte  Byte to send through the SPI interface.
 199                          */
 200                         static inline void SPI_SendByte(const uint8_t Byte) ATTR_ALWAYS_INLINE;
 201                         static inline void SPI_SendByte(const uint8_t Byte)
 202                         {
 203                                 SPDR = Byte;
 204                                 while (!(SPSR & (1 << SPIF)));
 205                         }
 206
 207                         /** Sends a dummy byte through the SPI interface, blocking until the transfer is complete. The response
 208                          *  byte from the attached SPI device is returned.
 209                          *
 210                          *  \return The response byte from the attached SPI device.
 211                          */
 212                         static inline uint8_t SPI_ReceiveByte(void) ATTR_ALWAYS_INLINE ATTR_WARN_UNUSED_RESULT;
 213                         static inline uint8_t SPI_ReceiveByte(void)
 214                         {
 215                                 SPDR = 0x00;
 216                                 while (!(SPSR & (1 << SPIF)));
 217                                 return SPDR;
 218                         }
 219
 220         /* Disable C linkage for C++ Compilers: */
 221                 #if defined(__cplusplus)
 222                         }
 223                 #endif
 224
 225 #endif
 226
 227 /** @} */
 228