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 << SPE)
  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                         /** SPI clock polarity mask for SPI_Init(). Indicates that the SCK should lead on the rising edge. */
  91                         #define SPI_SCK_LEAD_RISING            (0 << CPOL)
  92
  93                         /** SPI clock polarity mask for SPI_Init(). Indicates that the SCK should lead on the falling edge. */
  94                         #define SPI_SCK_LEAD_FALLING           (1 << CPOL)
  95
  96                         /** SPI data sample mode mask for SPI_Init(). Indicates that the data should sampled on the leading edge. */
  97                         #define SPI_SAMPLE_LEADING             (0 << CPHA)
  98
  99                         /** SPI data sample mode mask for SPI_Init(). Indicates that the data should be sampled on the trailing edge. */
 100                         #define SPI_SAMPLE_TRAILING            (1 << CPHA)
 101
 102                         /** SPI mode mask for SPI_Init(). Indicates that the SPI interface should be initialized into slave mode. */
 103                         #define SPI_MODE_SLAVE                 (0 << MSTR)
 104
 105                         /** SPI mode mask for SPI_Init(). Indicates that the SPI interface should be initialized into master mode. */
 106                         #define SPI_MODE_MASTER                (1 << MSTR)
 107
 108                 /* Inline Functions: */
 109                         /** Initializes the SPI subsystem, ready for transfers. Must be called before calling any other
 110                          *  SPI routines.
 111                          *
 112                          *  \param[in] SPIOptions  SPI Options, a mask consisting of one of each of the SPI_SPEED_*,
 113                          *                         SPI_SCK_*, SPI_SAMPLE_* and SPI_MODE_* masks
 114                          */
 115                         static inline void SPI_Init(const uint8_t SPIOptions)
 116                         {
 117                                 DDRB  |= ((1 << 1) | (1 << 2));
 118                                 PORTB |= ((1 << 0) | (1 << 3));
 119
 120                                 SPCR   = ((1 << SPE) | SPIOptions);
 121
 122                                 if (SPIOptions & SPI_USE_DOUBLESPEED)
 123                                   SPSR |= (1 << SPI2X);
 124                                 else
 125                                   SPSR &= ~(1 << SPI2X);
 126                         }
 127
 128                         /** Turns off the SPI driver, disabling and returning used hardware to their default configuration. */
 129                         static inline void SPI_ShutDown(void)
 130                         {
 131                                 DDRB  &= ~((1 << 1) | (1 << 2));
 132                                 PORTB &= ~((1 << 0) | (1 << 3));
 133
 134                                 SPCR   = 0;
 135                                 SPSR   = 0;
 136                         }
 137
 138                         /** Sends and receives a byte through the SPI interface, blocking until the transfer is complete.
 139                          *
 140                          *  \param[in] Byte  Byte to send through the SPI interface
 141                          *
 142                          *  \return Response byte from the attached SPI device
 143                          */
 144                         static inline uint8_t SPI_TransferByte(const uint8_t Byte) ATTR_ALWAYS_INLINE;
 145                         static inline uint8_t SPI_TransferByte(const uint8_t Byte)
 146                         {
 147                                 SPDR = Byte;
 148                                 while (!(SPSR & (1 << SPIF)));
 149                                 return SPDR;
 150                         }
 151
 152                         /** Sends a byte through the SPI interface, blocking until the transfer is complete. The response
 153                          *  byte sent to from the attached SPI device is ignored.
 154                          *
 155                          *  \param[in] Byte Byte to send through the SPI interface
 156                          */
 157                         static inline void SPI_SendByte(const uint8_t Byte) ATTR_ALWAYS_INLINE;
 158                         static inline void SPI_SendByte(const uint8_t Byte)
 159                         {
 160                                 SPDR = Byte;
 161                                 while (!(SPSR & (1 << SPIF)));
 162                         }
 163
 164                         /** Sends a dummy byte through the SPI interface, blocking until the transfer is complete. The response
 165                          *  byte from the attached SPI device is returned.
 166                          *
 167                          *  \return The response byte from the attached SPI device
 168                          */
 169                         static inline uint8_t SPI_ReceiveByte(void) ATTR_ALWAYS_INLINE ATTR_WARN_UNUSED_RESULT;
 170                         static inline uint8_t SPI_ReceiveByte(void)
 171                         {
 172                                 SPDR = 0x00;
 173                                 while (!(SPSR & (1 << SPIF)));
 174                                 return SPDR;
 175                         }
 176
 177         /* Disable C linkage for C++ Compilers: */
 178                 #if defined(__cplusplus)
 179                         }
 180                 #endif
 181
 182 #endif
 183
 184 /** @} */