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  *  Functions, macros, variables, enums and types related to the setup of a the SPI port.
  45  *
  46  *  @{
  47  */
  48
  49 #ifndef __SPI_H__
  50 #define __SPI_H__
  51
  52         /* Includes: */
  53                 #include <stdbool.h>
  54
  55         /* Enable C linkage for C++ Compilers: */
  56                 #if defined(__cplusplus)
  57                         extern "C" {
  58                 #endif
  59
  60         /* Private Interface - For use in library only: */
  61         #if !defined(__DOXYGEN__)
  62                 /* Macros: */
  63                         #define SPI_USE_DOUBLESPEED            (1 << 7)
  64         #endif
  65
  66         /* Public Interface - May be used in end-application: */
  67                 /* Macros: */
  68                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 2. */
  69                         #define SPI_SPEED_FCPU_DIV_2           SPI_USE_DOUBLESPEED
  70
  71                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 4. */
  72                         #define SPI_SPEED_FCPU_DIV_4           0
  73
  74                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 8. */
  75                         #define SPI_SPEED_FCPU_DIV_8           (SPI_USE_DOUBLESPEED | (1 << SPR0))
  76
  77                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 16. */
  78                         #define SPI_SPEED_FCPU_DIV_16          (1 << SPR0)
  79
  80                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 32. */
  81                         #define SPI_SPEED_FCPU_DIV_32          (SPI_USE_DOUBLESPEED | (1 << SPR1))
  82
  83                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 64. */
  84                         #define SPI_SPEED_FCPU_DIV_64          (SPI_USE_DOUBLESPEED | (1 << SPR1) | (1 << SPR0))
  85
  86                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 128. */
  87                         #define SPI_SPEED_FCPU_DIV_128         ((1 << SPR1) | (1 << SPR0))
  88
  89                 /* Inline Functions: */
  90                         /** Initializes the SPI subsystem, ready for transfers. Must be called before calling any other
  91                          *  SPI routines.
  92                          *
  93                          *  \param PrescalerMask  Prescaler mask to set the SPI clock speed
  94                          *  \param Master         If true, sets the SPI system to use master mode, slave if false
  95                          */
  96                         static inline void SPI_Init(const uint8_t PrescalerMask, const bool Master)
  97                         {
  98                                 DDRB  |= ((1 << 1) | (1 << 2));
  99                                 PORTB |= ((1 << 0) | (1 << 3));
 100
 101                                 SPCR   = ((1 << SPE) | (Master << MSTR) | (1 << CPOL) | (1 << CPHA) |
 102                                           (PrescalerMask & ~SPI_USE_DOUBLESPEED));
 103
 104                                 if (PrescalerMask & SPI_USE_DOUBLESPEED)
 105                                   SPSR |= (1 << SPI2X);
 106                                 else
 107                                   SPSR &= ~(1 << SPI2X);
 108                         }
 109
 110                         /** Sends and receives a byte through the SPI interface, blocking until the transfer is complete.
 111                          *
 112                          *  \param Byte  Byte to send through the SPI interface
 113                          *
 114                          *  \return Response byte from the attached SPI device
 115                          */
 116                         static inline uint8_t SPI_TransferByte(const uint8_t Byte) ATTR_ALWAYS_INLINE;
 117                         static inline uint8_t SPI_TransferByte(const uint8_t Byte)
 118                         {
 119                                 SPDR = Byte;
 120                                 while (!(SPSR & (1 << SPIF)));
 121                                 return SPDR;
 122                         }
 123
 124                         /** Sends a byte through the SPI interface, blocking until the transfer is complete. The response
 125                          *  byte sent to from the attached SPI device is ignored.
 126                          *
 127                          *  \param Byte Byte to send through the SPI interface
 128                          */
 129                         static inline void SPI_SendByte(const uint8_t Byte) ATTR_ALWAYS_INLINE;
 130                         static inline void SPI_SendByte(const uint8_t Byte)
 131                         {
 132                                 SPDR = Byte;
 133                                 while (!(SPSR & (1 << SPIF)));
 134                         }
 135
 136                         /** Sends a dummy byte through the SPI interface, blocking until the transfer is complete. The response
 137                          *  byte from the attached SPI device is returned.
 138                          *
 139                          *  \return The response byte from the attached SPI device
 140                          */
 141                         static inline uint8_t SPI_ReceiveByte(void) ATTR_ALWAYS_INLINE ATTR_WARN_UNUSED_RESULT;
 142                         static inline uint8_t SPI_ReceiveByte(void)
 143                         {
 144                                 SPDR = 0x00;
 145                                 while (!(SPSR & (1 << SPIF)));
 146                                 return SPDR;
 147                         }
 148
 149         /* Disable C linkage for C++ Compilers: */
 150                 #if defined(__cplusplus)
 151                         }
 152                 #endif
 153
 154 #endif
 155
 156 /** @} */