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 data order mask for SPI_Init(). Indicates that data should be shifted out MSB first. */
 104                         #define SPI_ORDER_MSB_FIRST            (0 << DORD)
 105
 106                         /** SPI data order mask for SPI_Init(). Indicates that data should be shifted out MSB first. */
 107                         #define SPI_ORDER_LSB_FIRST            (1 << DORD)
 108
 109                         /** SPI mode mask for SPI_Init(). Indicates that the SPI interface should be initialized into slave mode. */
 110                         #define SPI_MODE_SLAVE                 (0 << MSTR)
 111
 112                         /** SPI mode mask for SPI_Init(). Indicates that the SPI interface should be initialized into master mode. */
 113                         #define SPI_MODE_MASTER                (1 << MSTR)
 114
 115                 /* Inline Functions: */
 116                         /** Initialises the SPI subsystem, ready for transfers. Must be called before calling any other
 117                          *  SPI routines.
 118                          *
 119                          *  \param[in] SPIOptions  SPI Options, a mask consisting of one of each of the SPI_SPEED_*,
 120                          *                         SPI_SCK_*, SPI_SAMPLE_*, SPI_ORDER_* and SPI_MODE_* masks.
 121                          */
 122                         static inline void SPI_Init(const uint8_t SPIOptions)
 123                         {
 124                                 DDRB  |= ((1 << 1) | (1 << 2));
 125                                 DDRB  &= ((1 << 0) | (1 << 3));
 126                                 PORTB |= ((1 << 0) | (1 << 3));
 127
 128                                 SPCR   = ((1 << SPE) | SPIOptions);
 129
 130                                 if (SPIOptions & SPI_USE_DOUBLESPEED)
 131                                   SPSR |= (1 << SPI2X);
 132                                 else
 133                                   SPSR &= ~(1 << SPI2X);
 134                         }
 135
 136                         /** Turns off the SPI driver, disabling and returning used hardware to their default configuration. */
 137                         static inline void SPI_ShutDown(void)
 138                         {
 139                                 DDRB  &= ~((1 << 1) | (1 << 2));
 140                                 PORTB &= ~((1 << 0) | (1 << 3));
 141
 142                                 SPCR   = 0;
 143                                 SPSR   = 0;
 144                         }
 145
 146                         /** Sends and receives a byte through the SPI interface, blocking until the transfer is complete.
 147                          *
 148                          *  \param[in] Byte  Byte to send through the SPI interface.
 149                          *
 150                          *  \return Response byte from the attached SPI device.
 151                          */
 152                         static inline uint8_t SPI_TransferByte(const uint8_t Byte) ATTR_ALWAYS_INLINE;
 153                         static inline uint8_t SPI_TransferByte(const uint8_t Byte)
 154                         {
 155                                 SPDR = Byte;
 156                                 while (!(SPSR & (1 << SPIF)));
 157                                 return SPDR;
 158                         }
 159
 160                         /** Sends a byte through the SPI interface, blocking until the transfer is complete. The response
 161                          *  byte sent to from the attached SPI device is ignored.
 162                          *
 163                          *  \param[in] Byte  Byte to send through the SPI interface.
 164                          */
 165                         static inline void SPI_SendByte(const uint8_t Byte) ATTR_ALWAYS_INLINE;
 166                         static inline void SPI_SendByte(const uint8_t Byte)
 167                         {
 168                                 SPDR = Byte;
 169                                 while (!(SPSR & (1 << SPIF)));
 170                         }
 171
 172                         /** Sends a dummy byte through the SPI interface, blocking until the transfer is complete. The response
 173                          *  byte from the attached SPI device is returned.
 174                          *
 175                          *  \return The response byte from the attached SPI device.
 176                          */
 177                         static inline uint8_t SPI_ReceiveByte(void) ATTR_ALWAYS_INLINE ATTR_WARN_UNUSED_RESULT;
 178                         static inline uint8_t SPI_ReceiveByte(void)
 179                         {
 180                                 SPDR = 0x00;
 181                                 while (!(SPSR & (1 << SPIF)));
 182                                 return SPDR;
 183                         }
 184
 185         /* Disable C linkage for C++ Compilers: */
 186                 #if defined(__cplusplus)
 187                         }
 188                 #endif
 189
 190 #endif
 191
 192 /** @} */