LUFA/Drivers/Peripheral/SPI.h

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2011.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6            www.lufa-lib.org
   7 */
   8
   9 /*
  10   Copyright 2011  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  *  \brief Master include file for the SPI peripheral driver.
  33  *
  34  *  Hardware SPI subsystem driver for the supported USB AVRs models.
  35  */
  36
  37 /** \ingroup Group_PeripheralDrivers
  38  *  @defgroup Group_SPI SPI Driver - LUFA/Drivers/Peripheral/SPI.h
  39  *
  40  *  \section Sec_Dependencies Module Source Dependencies
  41  *  The following files must be built with any user project that uses this module:
  42  *    - None
  43  *
  44  *  \section Sec_ModDescription Module Description
  45  *  Driver for the hardware SPI port available on most AVR models. This module provides
  46  *  an easy to use driver for the setup of and transfer of data over the AVR's SPI port.
  47  *
  48  *  \section Sec_ExampleUsage Example Usage
  49  *  The following snippet is an example of how this module may be used within a typical
  50  *  application.
  51  *
  52  *  \code
  53  *      // Initialise the SPI driver before first use
  54  *      SPI_Init(SPI_SPEED_FCPU_DIV_2 | SPI_ORDER_MSB_FIRST | SPI_SCK_LEAD_FALLING |
  55  *               SPI_SAMPLE_TRAILING | SPI_MODE_MASTER);
  56  *
  57  *      // Send several bytes, ignoring the returned data
  58  *      SPI_SendByte(0x01);
  59  *      SPI_SendByte(0x02);
  60  *      SPI_SendByte(0x03);
  61  *
  62  *      // Receive several bytes, sending a dummy 0x00 byte each time
  63  *      uint8_t Byte1 = SPI_ReceiveByte();
  64  *      uint8_t Byte2 = SPI_ReceiveByte();
  65  *      uint8_t Byte3 = SPI_ReceiveByte();
  66  *
  67  *      // Send a byte, and store the received byte from the same transaction
  68  *      uint8_t ResponseByte = SPI_TransferByte(0xDC);
  69  *  \endcode
  70  *
  71  *  @{
  72  */
  73
  74 #ifndef __SPI_H__
  75 #define __SPI_H__
  76
  77         /* Includes: */
  78                 #include <stdbool.h>
  79
  80         /* Enable C linkage for C++ Compilers: */
  81                 #if defined(__cplusplus)
  82                         extern "C" {
  83                 #endif
  84
  85         /* Private Interface - For use in library only: */
  86         #if !defined(__DOXYGEN__)
  87                 /* Macros: */
  88                         #define SPI_USE_DOUBLESPEED            (1 << SPE)
  89         #endif
  90
  91         /* Public Interface - May be used in end-application: */
  92                 /* Macros: */
  93                         /** \name SPI Prescaler Configuration Masks */
  94                         //@{
  95                         /** SPI prescaler mask for \c SPI_Init(). Divides the system clock by a factor of 2. */
  96                         #define SPI_SPEED_FCPU_DIV_2           SPI_USE_DOUBLESPEED
  97
  98                         /** SPI prescaler mask for \c SPI_Init(). Divides the system clock by a factor of 4. */
  99                         #define SPI_SPEED_FCPU_DIV_4           0
 100
 101                         /** SPI prescaler mask for \c SPI_Init(). Divides the system clock by a factor of 8. */
 102                         #define SPI_SPEED_FCPU_DIV_8           (SPI_USE_DOUBLESPEED | (1 << SPR0))
 103
 104                         /** SPI prescaler mask for \c SPI_Init(). Divides the system clock by a factor of 16. */
 105                         #define SPI_SPEED_FCPU_DIV_16          (1 << SPR0)
 106
 107                         /** SPI prescaler mask for \c SPI_Init(). Divides the system clock by a factor of 32. */
 108                         #define SPI_SPEED_FCPU_DIV_32          (SPI_USE_DOUBLESPEED | (1 << SPR1))
 109
 110                         /** SPI prescaler mask for \c SPI_Init(). Divides the system clock by a factor of 64. */
 111                         #define SPI_SPEED_FCPU_DIV_64          (SPI_USE_DOUBLESPEED | (1 << SPR1) | (1 << SPR0))
 112
 113                         /** SPI prescaler mask for \c SPI_Init(). Divides the system clock by a factor of 128. */
 114                         #define SPI_SPEED_FCPU_DIV_128         ((1 << SPR1) | (1 << SPR0))
 115                         //@}
 116
 117                         /** \name SPI SCK Polarity Configuration Masks */
 118                         //@{
 119                         /** SPI clock polarity mask for \c SPI_Init(). Indicates that the SCK should lead on the rising edge. */
 120                         #define SPI_SCK_LEAD_RISING            (0 << CPOL)
 121
 122                         /** SPI clock polarity mask for \c SPI_Init(). Indicates that the SCK should lead on the falling edge. */
 123                         #define SPI_SCK_LEAD_FALLING           (1 << CPOL)
 124                         //@}
 125
 126                         /** \name SPI Sample Edge Configuration Masks */
 127                         //@{
 128                         /** SPI data sample mode mask for \c SPI_Init(). Indicates that the data should sampled on the leading edge. */
 129                         #define SPI_SAMPLE_LEADING             (0 << CPHA)
 130
 131                         /** SPI data sample mode mask for \c SPI_Init(). Indicates that the data should be sampled on the trailing edge. */
 132                         #define SPI_SAMPLE_TRAILING            (1 << CPHA)
 133                         //@}
 134
 135                         /** \name SPI Data Ordering Configuration Masks */
 136                         //@{
 137                         /** SPI data order mask for \c SPI_Init(). Indicates that data should be shifted out MSB first. */
 138                         #define SPI_ORDER_MSB_FIRST            (0 << DORD)
 139
 140                         /** SPI data order mask for \c SPI_Init(). Indicates that data should be shifted out MSB first. */
 141                         #define SPI_ORDER_LSB_FIRST            (1 << DORD)
 142                         //@}
 143
 144                         /** \name SPI Mode Configuration Masks */
 145                         //@{
 146                         /** SPI mode mask for \c SPI_Init(). Indicates that the SPI interface should be initialized into slave mode. */
 147                         #define SPI_MODE_SLAVE                 (0 << MSTR)
 148
 149                         /** SPI mode mask for \c SPI_Init(). Indicates that the SPI interface should be initialized into master mode. */
 150                         #define SPI_MODE_MASTER                (1 << MSTR)
 151                         //@}
 152
 153                 /* Inline Functions: */
 154                         /** Initialises the SPI subsystem, ready for transfers. Must be called before calling any other
 155                          *  SPI routines.
 156                          *
 157                          *  \param[in] SPIOptions  SPI Options, a mask consisting of one of each of the \c SPI_SPEED_*,
 158                          *                         \c SPI_SCK_*, \c SPI_SAMPLE_*, \c SPI_ORDER_* and \c SPI_MODE_* masks.
 159                          */
 160                         static inline void SPI_Init(const uint8_t SPIOptions)
 161                         {
 162                                 DDRB  |=  ((1 << 1) | (1 << 2));
 163                                 DDRB  &= ~((1 << 0) | (1 << 3));
 164                                 PORTB |=  ((1 << 0) | (1 << 3));
 165
 166                                 SPCR   = ((1 << SPE) | SPIOptions);
 167
 168                                 if (SPIOptions & SPI_USE_DOUBLESPEED)
 169                                   SPSR |= (1 << SPI2X);
 170                                 else
 171                                   SPSR &= ~(1 << SPI2X);
 172                         }
 173
 174                         /** Turns off the SPI driver, disabling and returning used hardware to their default configuration. */
 175                         static inline void SPI_ShutDown(void)
 176                         {
 177                                 DDRB  &= ~((1 << 1) | (1 << 2));
 178                                 PORTB &= ~((1 << 0) | (1 << 3));
 179
 180                                 SPCR   = 0;
 181                                 SPSR   = 0;
 182                         }
 183
 184                         /** Sends and receives a byte through the SPI interface, blocking until the transfer is complete.
 185                          *
 186                          *  \param[in] Byte  Byte to send through the SPI interface.
 187                          *
 188                          *  \return Response byte from the attached SPI device.
 189                          */
 190                         static inline uint8_t SPI_TransferByte(const uint8_t Byte) ATTR_ALWAYS_INLINE;
 191                         static inline uint8_t SPI_TransferByte(const uint8_t Byte)
 192                         {
 193                                 SPDR = Byte;
 194                                 while (!(SPSR & (1 << SPIF)));
 195                                 return SPDR;
 196                         }
 197
 198                         /** Sends a byte through the SPI interface, blocking until the transfer is complete. The response
 199                          *  byte sent to from the attached SPI device is ignored.
 200                          *
 201                          *  \param[in] Byte  Byte to send through the SPI interface.
 202                          */
 203                         static inline void SPI_SendByte(const uint8_t Byte) ATTR_ALWAYS_INLINE;
 204                         static inline void SPI_SendByte(const uint8_t Byte)
 205                         {
 206                                 SPDR = Byte;
 207                                 while (!(SPSR & (1 << SPIF)));
 208                         }
 209
 210                         /** Sends a dummy byte through the SPI interface, blocking until the transfer is complete. The response
 211                          *  byte from the attached SPI device is returned.
 212                          *
 213                          *  \return The response byte from the attached SPI device.
 214                          */
 215                         static inline uint8_t SPI_ReceiveByte(void) ATTR_ALWAYS_INLINE ATTR_WARN_UNUSED_RESULT;
 216                         static inline uint8_t SPI_ReceiveByte(void)
 217                         {
 218                                 SPDR = 0x00;
 219                                 while (!(SPSR & (1 << SPIF)));
 220                                 return SPDR;
 221                         }
 222
 223         /* Disable C linkage for C++ Compilers: */
 224                 #if defined(__cplusplus)
 225                         }
 226                 #endif
 227
 228 #endif
 229
 230 /** @} */
 231