LUFA/Drivers/Peripheral/SPI.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 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  *  @{
  49  */
  50
  51 #ifndef __SPI_H__
  52 #define __SPI_H__
  53
  54         /* Includes: */
  55                 #include <stdbool.h>
  56
  57         /* Enable C linkage for C++ Compilers: */
  58                 #if defined(__cplusplus)
  59                         extern "C" {
  60                 #endif
  61
  62         /* Private Interface - For use in library only: */
  63         #if !defined(__DOXYGEN__)
  64                 /* Macros: */
  65                         #define SPI_USE_DOUBLESPEED            (1 << SPE)
  66         #endif
  67
  68         /* Public Interface - May be used in end-application: */
  69                 /* Macros: */
  70                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 2. */
  71                         #define SPI_SPEED_FCPU_DIV_2           SPI_USE_DOUBLESPEED
  72
  73                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 4. */
  74                         #define SPI_SPEED_FCPU_DIV_4           0
  75
  76                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 8. */
  77                         #define SPI_SPEED_FCPU_DIV_8           (SPI_USE_DOUBLESPEED | (1 << SPR0))
  78
  79                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 16. */
  80                         #define SPI_SPEED_FCPU_DIV_16          (1 << SPR0)
  81
  82                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 32. */
  83                         #define SPI_SPEED_FCPU_DIV_32          (SPI_USE_DOUBLESPEED | (1 << SPR1))
  84
  85                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 64. */
  86                         #define SPI_SPEED_FCPU_DIV_64          (SPI_USE_DOUBLESPEED | (1 << SPR1) | (1 << SPR0))
  87
  88                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 128. */
  89                         #define SPI_SPEED_FCPU_DIV_128         ((1 << SPR1) | (1 << SPR0))
  90
  91                         /** SPI clock polarity mask for SPI_Init(). Indicates that the SCK should lead on the rising edge. */
  92                         #define SPI_SCK_LEAD_RISING            (0 << CPOL)
  93
  94                         /** SPI clock polarity mask for SPI_Init(). Indicates that the SCK should lead on the falling edge. */
  95                         #define SPI_SCK_LEAD_FALLING           (1 << CPOL)
  96
  97                         /** SPI data sample mode mask for SPI_Init(). Indicates that the data should sampled on the leading edge. */
  98                         #define SPI_SAMPLE_LEADING             (0 << CPHA)
  99
 100                         /** SPI data sample mode mask for SPI_Init(). Indicates that the data should be sampled on the trailing edge. */
 101                         #define SPI_SAMPLE_TRAILING            (1 << CPHA)
 102
 103                         /** SPI mode mask for SPI_Init(). Indicates that the SPI interface should be initialized into slave mode. */
 104                         #define SPI_MODE_SLAVE                 (0 << MSTR)
 105
 106                         /** SPI mode mask for SPI_Init(). Indicates that the SPI interface should be initialized into master mode. */
 107                         #define SPI_MODE_MASTER                (1 << MSTR)
 108
 109                 /* Inline Functions: */
 110                         /** Initializes the SPI subsystem, ready for transfers. Must be called before calling any other
 111                          *  SPI routines.
 112                          *
 113                          *  \param[in] SPIOptions  SPI Options, a mask consisting of one of each of the SPI_SPEED_*,
 114                          *                         SPI_SCK_*, SPI_SAMPLE_* and SPI_MODE_* masks.
 115                          */
 116                         static inline void SPI_Init(const uint8_t SPIOptions)
 117                         {
 118                                 DDRB  |= ((1 << 1) | (1 << 2));
 119                                 PORTB |= ((1 << 0) | (1 << 3));
 120
 121                                 SPCR   = ((1 << SPE) | SPIOptions);
 122
 123                                 if (SPIOptions & SPI_USE_DOUBLESPEED)
 124                                   SPSR |= (1 << SPI2X);
 125                                 else
 126                                   SPSR &= ~(1 << SPI2X);
 127                         }
 128
 129                         /** Turns off the SPI driver, disabling and returning used hardware to their default configuration. */
 130                         static inline void SPI_ShutDown(void)
 131                         {
 132                                 DDRB  &= ~((1 << 1) | (1 << 2));
 133                                 PORTB &= ~((1 << 0) | (1 << 3));
 134
 135                                 SPCR   = 0;
 136                                 SPSR   = 0;
 137                         }
 138
 139                         /** Sends and receives a byte through the SPI interface, blocking until the transfer is complete.
 140                          *
 141                          *  \param[in] Byte  Byte to send through the SPI interface.
 142                          *
 143                          *  \return Response byte from the attached SPI device.
 144                          */
 145                         static inline uint8_t SPI_TransferByte(const uint8_t Byte) ATTR_ALWAYS_INLINE;
 146                         static inline uint8_t SPI_TransferByte(const uint8_t Byte)
 147                         {
 148                                 SPDR = Byte;
 149                                 while (!(SPSR & (1 << SPIF)));
 150                                 return SPDR;
 151                         }
 152
 153                         /** Sends a byte through the SPI interface, blocking until the transfer is complete. The response
 154                          *  byte sent to from the attached SPI device is ignored.
 155                          *
 156                          *  \param[in] Byte  Byte to send through the SPI interface.
 157                          */
 158                         static inline void SPI_SendByte(const uint8_t Byte) ATTR_ALWAYS_INLINE;
 159                         static inline void SPI_SendByte(const uint8_t Byte)
 160                         {
 161                                 SPDR = Byte;
 162                                 while (!(SPSR & (1 << SPIF)));
 163                         }
 164
 165                         /** Sends a dummy byte through the SPI interface, blocking until the transfer is complete. The response
 166                          *  byte from the attached SPI device is returned.
 167                          *
 168                          *  \return The response byte from the attached SPI device.
 169                          */
 170                         static inline uint8_t SPI_ReceiveByte(void) ATTR_ALWAYS_INLINE ATTR_WARN_UNUSED_RESULT;
 171                         static inline uint8_t SPI_ReceiveByte(void)
 172                         {
 173                                 SPDR = 0x00;
 174                                 while (!(SPSR & (1 << SPIF)));
 175                                 return SPDR;
 176                         }
 177
 178         /* Disable C linkage for C++ Compilers: */
 179                 #if defined(__cplusplus)
 180                         }
 181                 #endif
 182
 183 #endif
 184
 185 /** @} */