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 <avr/io.h>
  55                 #include <stdbool.h>
  56
  57         /* Preprocessor Checks: */
  58                 #if !defined(__INCLUDE_FROM_SPI_H)
  59                         #error Do not include this file directly. Include LUFA/Drivers/Peripheral/SPI.h instead.
  60                 #endif
  61
  62         /* Enable C linkage for C++ Compilers: */
  63                 #if defined(__cplusplus)
  64                         extern "C" {
  65                 #endif
  66
  67         /* Private Interface - For use in library only: */
  68         #if !defined(__DOXYGEN__)
  69                 /* Macros: */
  70                         #define SPI_USE_DOUBLESPEED            (1 << SPE)
  71         #endif
  72
  73         /* Public Interface - May be used in end-application: */
  74                 /* Macros: */
  75                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 2. */
  76                         #define SPI_SPEED_FCPU_DIV_2           SPI_USE_DOUBLESPEED
  77
  78                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 4. */
  79                         #define SPI_SPEED_FCPU_DIV_4           0
  80
  81                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 8. */
  82                         #define SPI_SPEED_FCPU_DIV_8           (SPI_USE_DOUBLESPEED | (1 << SPR0))
  83
  84                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 16. */
  85                         #define SPI_SPEED_FCPU_DIV_16          (1 << SPR0)
  86
  87                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 32. */
  88                         #define SPI_SPEED_FCPU_DIV_32          (SPI_USE_DOUBLESPEED | (1 << SPR1))
  89
  90                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 64. */
  91                         #define SPI_SPEED_FCPU_DIV_64          (SPI_USE_DOUBLESPEED | (1 << SPR1) | (1 << SPR0))
  92
  93                         /** SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 128. */
  94                         #define SPI_SPEED_FCPU_DIV_128         ((1 << SPR1) | (1 << SPR0))
  95
  96                         /** SPI clock polarity mask for SPI_Init(). Indicates that the SCK should lead on the rising edge. */
  97                         #define SPI_SCK_LEAD_RISING            (0 << CPOL)
  98
  99                         /** SPI clock polarity mask for SPI_Init(). Indicates that the SCK should lead on the falling edge. */
 100                         #define SPI_SCK_LEAD_FALLING           (1 << CPOL)
 101
 102                         /** SPI data sample mode mask for SPI_Init(). Indicates that the data should sampled on the leading edge. */
 103                         #define SPI_SAMPLE_LEADING             (0 << CPHA)
 104
 105                         /** SPI data sample mode mask for SPI_Init(). Indicates that the data should be sampled on the trailing edge. */
 106                         #define SPI_SAMPLE_TRAILING            (1 << CPHA)
 107
 108                         /** SPI mode mask for SPI_Init(). Indicates that the SPI interface should be initialized into slave mode. */
 109                         #define SPI_MODE_SLAVE                 (0 << MSTR)
 110
 111                         /** SPI mode mask for SPI_Init(). Indicates that the SPI interface should be initialized into master mode. */
 112                         #define SPI_MODE_MASTER                (1 << MSTR)
 113
 114                 /* Inline Functions: */
 115                         /** Initialises the SPI subsystem, ready for transfers. Must be called before calling any other
 116                          *  SPI routines.
 117                          *
 118                          *  \param[in] SPIOptions  SPI Options, a mask consisting of one of each of the SPI_SPEED_*,
 119                          *                         SPI_SCK_*, SPI_SAMPLE_* and SPI_MODE_* masks
 120                          */
 121                         static inline void SPI_Init(const uint8_t SPIOptions)
 122                         {
 123                                 DDRB  |= ((1 << 1) | (1 << 2));
 124                                 PORTB |= ((1 << 0) | (1 << 3));
 125
 126                                 SPCR   = ((1 << SPE) | SPIOptions);
 127
 128                                 if (SPIOptions & SPI_USE_DOUBLESPEED)
 129                                   SPSR |= (1 << SPI2X);
 130                                 else
 131                                   SPSR &= ~(1 << SPI2X);
 132                         }
 133
 134                         /** Turns off the SPI driver, disabling and returning used hardware to their default configuration. */
 135                         static inline void SPI_ShutDown(void)
 136                         {
 137                                 DDRB  &= ~((1 << 1) | (1 << 2));
 138                                 PORTB &= ~((1 << 0) | (1 << 3));
 139
 140                                 SPCR   = 0;
 141                                 SPSR   = 0;
 142                         }
 143
 144                         /** Sends and receives a byte through the SPI interface, blocking until the transfer is complete.
 145                          *
 146                          *  \param[in] Byte  Byte to send through the SPI interface
 147                          *
 148                          *  \return Response byte from the attached SPI device
 149                          */
 150                         static inline uint8_t SPI_TransferByte(const uint8_t Byte) ATTR_ALWAYS_INLINE;
 151                         static inline uint8_t SPI_TransferByte(const uint8_t Byte)
 152                         {
 153                                 SPDR = Byte;
 154                                 while (!(SPSR & (1 << SPIF)));
 155                                 return SPDR;
 156                         }
 157
 158                         /** Sends a byte through the SPI interface, blocking until the transfer is complete. The response
 159                          *  byte sent to from the attached SPI device is ignored.
 160                          *
 161                          *  \param[in] Byte Byte to send through the SPI interface
 162                          */
 163                         static inline void SPI_SendByte(const uint8_t Byte) ATTR_ALWAYS_INLINE;
 164                         static inline void SPI_SendByte(const uint8_t Byte)
 165                         {
 166                                 SPDR = Byte;
 167                                 while (!(SPSR & (1 << SPIF)));
 168                         }
 169
 170                         /** Sends a dummy byte through the SPI interface, blocking until the transfer is complete. The response
 171                          *  byte from the attached SPI device is returned.
 172                          *
 173                          *  \return The response byte from the attached SPI device
 174                          */
 175                         static inline uint8_t SPI_ReceiveByte(void) ATTR_ALWAYS_INLINE ATTR_WARN_UNUSED_RESULT;
 176                         static inline uint8_t SPI_ReceiveByte(void)
 177                         {
 178                                 SPDR = 0x00;
 179                                 while (!(SPSR & (1 << SPIF)));
 180                                 return SPDR;
 181                         }
 182
 183         /* Disable C linkage for C++ Compilers: */
 184                 #if defined(__cplusplus)
 185                         }
 186                 #endif
 187
 188 #endif
 189
 190 /** @} */