LUFA/Drivers/Peripheral/SPI.h

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2009.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6       www.fourwalledcubicle.com
   7 */
   8
   9 /*
  10   Copyright 2009  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  11
  12   Permission to use, copy, modify, and distribute this software
  13   and its documentation for any purpose and without fee is hereby
  14   granted, provided that the above copyright notice appear in all
  15   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  *
  33  *  Hardware SPI subsystem driver for the supported USB AVRs models.
  34  */
  35
  36 /** \ingroup Group_PeripheralDrivers
  37  *  @defgroup Group_SPI SPI Driver - LUFA/Drivers/Peripheral/SPI.h
  38  *
  39  *  \section Sec_Dependencies Module Source Dependencies
  40  *  The following files must be built with any user project that uses this module:
  41  *    - None
  42  *
  43  *  \section Module Description
  44  *  Driver for the hardware SPI port avaliable on most AVR models. This module provides
  45  *  an easy to use driver for the setup of and transfer of data over the AVR's SPI port.
  46  *
  47  *  @{
  48  */
  49
  50 #ifndef __SPI_H__
  51 #define __SPI_H__
  52
  53         /* Includes: */
  54                 #include <stdbool.h>
  55
  56         /* Enable C linkage for C++ Compilers: */
  57                 #if defined(__cplusplus)
  58                         extern "C" {
  59                 #endif
  60
  61         /* Private Interface - For use in library only: */
  62         #if !defined(__DOXYGEN__)
  63                 /* Macros: */
  64                         #define SPI_USE_DOUBLESPEED            (1 << 7)
  65         #endif
  66
  67         /* Public Interface - May be used in end-application: */
  68                 /* Macros: */
  69                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 2. */
  70                         #define SPI_SPEED_FCPU_DIV_2           SPI_USE_DOUBLESPEED
  71
  72                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 4. */
  73                         #define SPI_SPEED_FCPU_DIV_4           0
  74
  75                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 8. */
  76                         #define SPI_SPEED_FCPU_DIV_8           (SPI_USE_DOUBLESPEED | (1 << SPR0))
  77
  78                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 16. */
  79                         #define SPI_SPEED_FCPU_DIV_16          (1 << SPR0)
  80
  81                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 32. */
  82                         #define SPI_SPEED_FCPU_DIV_32          (SPI_USE_DOUBLESPEED | (1 << SPR1))
  83
  84                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 64. */
  85                         #define SPI_SPEED_FCPU_DIV_64          (SPI_USE_DOUBLESPEED | (1 << SPR1) | (1 << SPR0))
  86
  87                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 128. */
  88                         #define SPI_SPEED_FCPU_DIV_128         ((1 << SPR1) | (1 << SPR0))
  89
  90                 /* Inline Functions: */
  91                         /** Initializes the SPI subsystem, ready for transfers. Must be called before calling any other
  92                          *  SPI routines.
  93                          *
  94                          *  \param[in] PrescalerMask  Prescaler mask to set the SPI clock speed
  95                          *  \param[in] Master         If true, sets the SPI system to use master mode, slave if false
  96                          */
  97                         static inline void SPI_Init(const uint8_t PrescalerMask, const bool Master)
  98                         {
  99                                 DDRB  |= ((1 << 1) | (1 << 2));
 100                                 PORTB |= ((1 << 0) | (1 << 3));
 101
 102                                 SPCR   = ((1 << SPE) | (Master << MSTR) | (1 << CPOL) | (1 << CPHA) |
 103                                           (PrescalerMask & ~SPI_USE_DOUBLESPEED));
 104
 105                                 if (PrescalerMask & SPI_USE_DOUBLESPEED)
 106                                   SPSR |= (1 << SPI2X);
 107                                 else
 108                                   SPSR &= ~(1 << SPI2X);
 109                         }
 110
 111                         /** Sends and receives a byte through the SPI interface, blocking until the transfer is complete.
 112                          *
 113                          *  \param[in] Byte  Byte to send through the SPI interface
 114                          *
 115                          *  \return Response byte from the attached SPI device
 116                          */
 117                         static inline uint8_t SPI_TransferByte(const uint8_t Byte) ATTR_ALWAYS_INLINE;
 118                         static inline uint8_t SPI_TransferByte(const uint8_t Byte)
 119                         {
 120                                 SPDR = Byte;
 121                                 while (!(SPSR & (1 << SPIF)));
 122                                 return SPDR;
 123                         }
 124
 125                         /** Sends a byte through the SPI interface, blocking until the transfer is complete. The response
 126                          *  byte sent to from the attached SPI device is ignored.
 127                          *
 128                          *  \param[in] Byte Byte to send through the SPI interface
 129                          */
 130                         static inline void SPI_SendByte(const uint8_t Byte) ATTR_ALWAYS_INLINE;
 131                         static inline void SPI_SendByte(const uint8_t Byte)
 132                         {
 133                                 SPDR = Byte;
 134                                 while (!(SPSR & (1 << SPIF)));
 135                         }
 136
 137                         /** Sends a dummy byte through the SPI interface, blocking until the transfer is complete. The response
 138                          *  byte from the attached SPI device is returned.
 139                          *
 140                          *  \return The response byte from the attached SPI device
 141                          */
 142                         static inline uint8_t SPI_ReceiveByte(void) ATTR_ALWAYS_INLINE ATTR_WARN_UNUSED_RESULT;
 143                         static inline uint8_t SPI_ReceiveByte(void)
 144                         {
 145                                 SPDR = 0x00;
 146                                 while (!(SPSR & (1 << SPIF)));
 147                                 return SPDR;
 148                         }
 149
 150         /* Disable C linkage for C++ Compilers: */
 151                 #if defined(__cplusplus)
 152                         }
 153                 #endif
 154
 155 #endif
 156
 157 /** @} */