LUFA/Drivers/Peripheral/AVR8/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  *
  33  *  SPI driver for the 8-bit AVRs.
  34  *
  35  *  \note This file should not be included directly. It is automatically included as needed by the SPI driver
  36  *        dispatch header located in LUFA/Drivers/Peripheral/SPI.h.
  37  */
  38
  39 /** \ingroup Group_SPI
  40  *  @defgroup Group_SPI_AVR8 8-Bit AVR SPI Driver
  41  *
  42  *  SPI driver for the 8-bit AVRs.
  43  *
  44  *  \note This file should not be included directly. It is automatically included as needed by the ADC driver
  45  *        dispatch header located in LUFA/Drivers/Peripheral/SPI.h.
  46  *
  47  *  @{
  48  */
  49
  50 #ifndef __SPI_AVR8_H__
  51 #define __SPI_AVR8_H__
  52
  53         /* Includes: */
  54                 #include <stdbool.h>
  55
  56         /* Preprocessor Checks: */
  57                 #if !defined(__INCLUDE_FROM_SPI_H)
  58                         #error Do not include this file directly. Include LUFA/Drivers/Peripheral/SPI.h instead.
  59                 #endif
  60
  61         /* Enable C linkage for C++ Compilers: */
  62                 #if defined(__cplusplus)
  63                         extern "C" {
  64                 #endif
  65
  66         /* Private Interface - For use in library only: */
  67         #if !defined(__DOXYGEN__)
  68                 /* Macros: */
  69                         #define SPI_USE_DOUBLESPEED            (1 << SPE)
  70         #endif
  71
  72         /* Public Interface - May be used in end-application: */
  73                 /* Macros: */
  74                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 2. */
  75                         #define SPI_SPEED_FCPU_DIV_2           SPI_USE_DOUBLESPEED
  76
  77                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 4. */
  78                         #define SPI_SPEED_FCPU_DIV_4           0
  79
  80                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 8. */
  81                         #define SPI_SPEED_FCPU_DIV_8           (SPI_USE_DOUBLESPEED | (1 << SPR0))
  82
  83                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 16. */
  84                         #define SPI_SPEED_FCPU_DIV_16          (1 << SPR0)
  85
  86                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 32. */
  87                         #define SPI_SPEED_FCPU_DIV_32          (SPI_USE_DOUBLESPEED | (1 << SPR1))
  88
  89                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 64. */
  90                         #define SPI_SPEED_FCPU_DIV_64          (SPI_USE_DOUBLESPEED | (1 << SPR1) | (1 << SPR0))
  91
  92                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 128. */
  93                         #define SPI_SPEED_FCPU_DIV_128         ((1 << SPR1) | (1 << SPR0))
  94
  95                         /** SPI clock polarity mask for SPI_Init(). Indicates that the SCK should lead on the rising edge. */
  96                         #define SPI_SCK_LEAD_RISING            (0 << CPOL)
  97
  98                         /** SPI clock polarity mask for SPI_Init(). Indicates that the SCK should lead on the falling edge. */
  99                         #define SPI_SCK_LEAD_FALLING           (1 << CPOL)
 100
 101                         /** SPI data sample mode mask for SPI_Init(). Indicates that the data should sampled on the leading edge. */
 102                         #define SPI_SAMPLE_LEADING             (0 << CPHA)
 103
 104                         /** SPI data sample mode mask for SPI_Init(). Indicates that the data should be sampled on the trailing edge. */
 105                         #define SPI_SAMPLE_TRAILING            (1 << CPHA)
 106
 107                         /** SPI mode mask for SPI_Init(). Indicates that the SPI interface should be initialized into slave mode. */
 108                         #define SPI_MODE_SLAVE                 (0 << MSTR)
 109
 110                         /** SPI mode mask for SPI_Init(). Indicates that the SPI interface should be initialized into master mode. */
 111                         #define SPI_MODE_MASTER                (1 << MSTR)
 112
 113                 /* Inline Functions: */
 114                         /** Initialises the SPI subsystem, ready for transfers. Must be called before calling any other
 115                          *  SPI routines.
 116                          *
 117                          *  \param[in] SPIOptions  SPI Options, a mask consisting of one of each of the SPI_SPEED_*,
 118                          *                         SPI_SCK_*, SPI_SAMPLE_* and SPI_MODE_* masks
 119                          */
 120                         static inline void SPI_Init(const uint8_t SPIOptions)
 121                         {
 122                                 DDRB  |= ((1 << 1) | (1 << 2));
 123                                 PORTB |= ((1 << 0) | (1 << 3));
 124
 125                                 SPCR   = ((1 << SPE) | SPIOptions);
 126
 127                                 if (SPIOptions & SPI_USE_DOUBLESPEED)
 128                                   SPSR |= (1 << SPI2X);
 129                                 else
 130                                   SPSR &= ~(1 << SPI2X);
 131                         }
 132
 133                         /** Turns off the SPI driver, disabling and returning used hardware to their default configuration. */
 134                         static inline void SPI_ShutDown(void)
 135                         {
 136                                 DDRB  &= ~((1 << 1) | (1 << 2));
 137                                 PORTB &= ~((1 << 0) | (1 << 3));
 138
 139                                 SPCR   = 0;
 140                                 SPSR   = 0;
 141                         }
 142
 143                         /** Sends and receives a byte through the SPI interface, blocking until the transfer is complete.
 144                          *
 145                          *  \param[in] Byte  Byte to send through the SPI interface
 146                          *
 147                          *  \return Response byte from the attached SPI device
 148                          */
 149                         static inline uint8_t SPI_TransferByte(const uint8_t Byte) ATTR_ALWAYS_INLINE;
 150                         static inline uint8_t SPI_TransferByte(const uint8_t Byte)
 151                         {
 152                                 SPDR = Byte;
 153                                 while (!(SPSR & (1 << SPIF)));
 154                                 return SPDR;
 155                         }
 156
 157                         /** Sends a byte through the SPI interface, blocking until the transfer is complete. The response
 158                          *  byte sent to from the attached SPI device is ignored.
 159                          *
 160                          *  \param[in] Byte Byte to send through the SPI interface
 161                          */
 162                         static inline void SPI_SendByte(const uint8_t Byte) ATTR_ALWAYS_INLINE;
 163                         static inline void SPI_SendByte(const uint8_t Byte)
 164                         {
 165                                 SPDR = Byte;
 166                                 while (!(SPSR & (1 << SPIF)));
 167                         }
 168
 169                         /** Sends a dummy byte through the SPI interface, blocking until the transfer is complete. The response
 170                          *  byte from the attached SPI device is returned.
 171                          *
 172                          *  \return The response byte from the attached SPI device
 173                          */
 174                         static inline uint8_t SPI_ReceiveByte(void) ATTR_ALWAYS_INLINE ATTR_WARN_UNUSED_RESULT;
 175                         static inline uint8_t SPI_ReceiveByte(void)
 176                         {
 177                                 SPDR = 0x00;
 178                                 while (!(SPSR & (1 << SPIF)));
 179                                 return SPDR;
 180                         }
 181
 182         /* Disable C linkage for C++ Compilers: */
 183                 #if defined(__cplusplus)
 184                         }
 185                 #endif
 186
 187 #endif
 188
 189 /** @} */