LUFA/Drivers/Peripheral/AVR8/SPI_AVR8.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 SPI Peripheral Driver (AVR8)
  33  *
  34  *  On-chip SPI driver for the 8-bit AVR microcontrollers.
  35  *
  36  *  \note This file should not be included directly. It is automatically included as needed by the SPI driver
  37  *        dispatch header located in LUFA/Drivers/Peripheral/SPI.h.
  38  */
  39
  40 /** \ingroup Group_SPI
  41  *  \defgroup Group_SPI_AVR8 SPI Peripheral Driver (AVR8)
  42  *
  43  *  \section Sec_ModDescription Module Description
  44  *  Driver for the hardware SPI port available on most 8-bit AVR microcontroller models. This
  45  *  module provides an easy to use driver for the setup and transfer of data over the
  46  *  AVR's SPI port.
  47  *
  48  *  \note This file should not be included directly. It is automatically included as needed by the SPI driver
  49  *        dispatch header located in LUFA/Drivers/Peripheral/SPI.h.
  50  *
  51  *  \section Sec_ExampleUsage Example Usage
  52  *  The following snippet is an example of how this module may be used within a typical
  53  *  application.
  54  *
  55  *  \code
  56  *      // Initialize the SPI driver before first use
  57  *      SPI_Init(SPI_SPEED_FCPU_DIV_2 | SPI_ORDER_MSB_FIRST | SPI_SCK_LEAD_FALLING |
  58  *               SPI_SAMPLE_TRAILING | SPI_MODE_MASTER);
  59  *
  60  *      // Send several bytes, ignoring the returned data
  61  *      SPI_SendByte(0x01);
  62  *      SPI_SendByte(0x02);
  63  *      SPI_SendByte(0x03);
  64  *
  65  *      // Receive several bytes, sending a dummy 0x00 byte each time
  66  *      uint8_t Byte1 = SPI_ReceiveByte();
  67  *      uint8_t Byte2 = SPI_ReceiveByte();
  68  *      uint8_t Byte3 = SPI_ReceiveByte();
  69  *
  70  *      // Send a byte, and store the received byte from the same transaction
  71  *      uint8_t ResponseByte = SPI_TransferByte(0xDC);
  72  *  \endcode
  73  *
  74  *  @{
  75  */
  76
  77 #ifndef __SPI_AVR8_H__
  78 #define __SPI_AVR8_H__
  79
  80         /* Includes: */
  81                 #include "../../../Common/Common.h"
  82
  83         /* Enable C linkage for C++ Compilers: */
  84                 #if defined(__cplusplus)
  85                         extern "C" {
  86                 #endif
  87
  88         /* Preprocessor Checks: */
  89                 #if !defined(__INCLUDE_FROM_SPI_H)
  90                         #error Do not include this file directly. Include LUFA/Drivers/Peripheral/SPI.h instead.
  91                 #endif
  92
  93         /* Private Interface - For use in library only: */
  94         #if !defined(__DOXYGEN__)
  95                 /* Macros: */
  96                         #define SPI_USE_DOUBLESPEED            (1 << SPE)
  97         #endif
  98
  99         /* Public Interface - May be used in end-application: */
 100                 /* Macros: */
 101                         /** \name SPI Prescaler Configuration Masks */
 102                         //@{
 103                         /** SPI prescaler mask for \c SPI_Init(). Divides the system clock by a factor of 2. */
 104                         #define SPI_SPEED_FCPU_DIV_2           SPI_USE_DOUBLESPEED
 105
 106                         /** SPI prescaler mask for \c SPI_Init(). Divides the system clock by a factor of 4. */
 107                         #define SPI_SPEED_FCPU_DIV_4           0
 108
 109                         /** SPI prescaler mask for \c SPI_Init(). Divides the system clock by a factor of 8. */
 110                         #define SPI_SPEED_FCPU_DIV_8           (SPI_USE_DOUBLESPEED | (1 << SPR0))
 111
 112                         /** SPI prescaler mask for \c SPI_Init(). Divides the system clock by a factor of 16. */
 113                         #define SPI_SPEED_FCPU_DIV_16          (1 << SPR0)
 114
 115                         /** SPI prescaler mask for \c SPI_Init(). Divides the system clock by a factor of 32. */
 116                         #define SPI_SPEED_FCPU_DIV_32          (SPI_USE_DOUBLESPEED | (1 << SPR1))
 117
 118                         /** SPI prescaler mask for \c SPI_Init(). Divides the system clock by a factor of 64. */
 119                         #define SPI_SPEED_FCPU_DIV_64          (SPI_USE_DOUBLESPEED | (1 << SPR1) | (1 << SPR0))
 120
 121                         /** SPI prescaler mask for \c SPI_Init(). Divides the system clock by a factor of 128. */
 122                         #define SPI_SPEED_FCPU_DIV_128         ((1 << SPR1) | (1 << SPR0))
 123                         //@}
 124
 125                         /** \name SPI SCK Polarity Configuration Masks */
 126                         //@{
 127                         /** SPI clock polarity mask for \c SPI_Init(). Indicates that the SCK should lead on the rising edge. */
 128                         #define SPI_SCK_LEAD_RISING            (0 << CPOL)
 129
 130                         /** SPI clock polarity mask for \c SPI_Init(). Indicates that the SCK should lead on the falling edge. */
 131                         #define SPI_SCK_LEAD_FALLING           (1 << CPOL)
 132                         //@}
 133
 134                         /** \name SPI Sample Edge Configuration Masks */
 135                         //@{
 136                         /** SPI data sample mode mask for \c SPI_Init(). Indicates that the data should sampled on the leading edge. */
 137                         #define SPI_SAMPLE_LEADING             (0 << CPHA)
 138
 139                         /** SPI data sample mode mask for \c SPI_Init(). Indicates that the data should be sampled on the trailing edge. */
 140                         #define SPI_SAMPLE_TRAILING            (1 << CPHA)
 141                         //@}
 142
 143                         /** \name SPI Data Ordering Configuration Masks */
 144                         //@{
 145                         /** SPI data order mask for \c SPI_Init(). Indicates that data should be shifted out MSB first. */
 146                         #define SPI_ORDER_MSB_FIRST            (0 << DORD)
 147
 148                         /** SPI data order mask for \c SPI_Init(). Indicates that data should be shifted out LSB first. */
 149                         #define SPI_ORDER_LSB_FIRST            (1 << DORD)
 150                         //@}
 151
 152                         /** \name SPI Mode Configuration Masks */
 153                         //@{
 154                         /** SPI mode mask for \c SPI_Init(). Indicates that the SPI interface should be initialized into slave mode. */
 155                         #define SPI_MODE_SLAVE                 (0 << MSTR)
 156
 157                         /** SPI mode mask for \c SPI_Init(). Indicates that the SPI interface should be initialized into master mode. */
 158                         #define SPI_MODE_MASTER                (1 << MSTR)
 159                         //@}
 160
 161                 /* Inline Functions: */
 162                         /** Initializes the SPI subsystem, ready for transfers. Must be called before calling any other
 163                          *  SPI routines.
 164                          *
 165                          *  \param[in] SPIOptions  SPI Options, a mask consisting of one of each of the \c SPI_SPEED_*,
 166                          *                         \c SPI_SCK_*, \c SPI_SAMPLE_*, \c SPI_ORDER_* and \c SPI_MODE_* masks.
 167                          */
 168                         static inline void SPI_Init(const uint8_t SPIOptions)
 169                         {
 170                                 /* Prevent high rise times on PB.0 (/SS) from forcing a change to SPI slave mode */
 171                                 DDRB  |= (1 << 0);
 172                                 PORTB |= (1 << 0);
 173
 174                                 DDRB  |=  ((1 << 1) | (1 << 2));
 175                                 DDRB  &= ~(1 << 3);
 176                                 PORTB |=  (1 << 3);
 177
 178                                 if (SPIOptions & SPI_USE_DOUBLESPEED)
 179                                   SPSR |= (1 << SPI2X);
 180                                 else
 181                                   SPSR &= ~(1 << SPI2X);
 182
 183                                 /* Switch /SS to input mode after configuration to allow for forced mode changes */
 184                                 DDRB &= ~(1 << 0);
 185
 186                                 SPCR  = ((1 << SPE) | SPIOptions);
 187                         }
 188
 189                         /** Turns off the SPI driver, disabling and returning used hardware to their default configuration. */
 190                         static inline void SPI_Disable(void)
 191                         {
 192                                 DDRB  &= ~((1 << 1) | (1 << 2));
 193                                 PORTB &= ~((1 << 0) | (1 << 3));
 194
 195                                 SPCR   = 0;
 196                                 SPSR   = 0;
 197                         }
 198
 199                         /** Retrieves the currently selected SPI mode, once the SPI interface has been configured.
 200                          *
 201                          *  \return \ref SPI_MODE_MASTER if the interface is currently in SPI Master mode, \ref SPI_MODE_SLAVE otherwise
 202                          */
 203                         static inline uint8_t SPI_GetCurrentMode(void) ATTR_ALWAYS_INLINE;
 204                         static inline uint8_t SPI_GetCurrentMode(void)
 205                         {
 206                                 return (SPCR & SPI_MODE_MASTER);
 207                         }
 208
 209                         /** Sends and receives a byte through the SPI interface, blocking until the transfer is complete.
 210                          *
 211                          *  \param[in] Byte  Byte to send through the SPI interface.
 212                          *
 213                          *  \return Response byte from the attached SPI device.
 214                          */
 215                         static inline uint8_t SPI_TransferByte(const uint8_t Byte) ATTR_ALWAYS_INLINE;
 216                         static inline uint8_t SPI_TransferByte(const uint8_t Byte)
 217                         {
 218                                 SPDR = Byte;
 219                                 while (!(SPSR & (1 << SPIF)));
 220                                 return SPDR;
 221                         }
 222
 223                         /** Sends a byte through the SPI interface, blocking until the transfer is complete. The response
 224                          *  byte sent to from the attached SPI device is ignored.
 225                          *
 226                          *  \param[in] Byte  Byte to send through the SPI interface.
 227                          */
 228                         static inline void SPI_SendByte(const uint8_t Byte) ATTR_ALWAYS_INLINE;
 229                         static inline void SPI_SendByte(const uint8_t Byte)
 230                         {
 231                                 SPDR = Byte;
 232                                 while (!(SPSR & (1 << SPIF)));
 233                         }
 234
 235                         /** Sends a dummy byte through the SPI interface, blocking until the transfer is complete. The response
 236                          *  byte from the attached SPI device is returned.
 237                          *
 238                          *  \return The response byte from the attached SPI device.
 239                          */
 240                         static inline uint8_t SPI_ReceiveByte(void) ATTR_ALWAYS_INLINE ATTR_WARN_UNUSED_RESULT;
 241                         static inline uint8_t SPI_ReceiveByte(void)
 242                         {
 243                                 SPDR = 0x00;
 244                                 while (!(SPSR & (1 << SPIF)));
 245                                 return SPDR;
 246                         }
 247
 248         /* Disable C linkage for C++ Compilers: */
 249                 #if defined(__cplusplus)
 250                         }
 251                 #endif
 252
 253 #endif
 254
 255 /** @} */
 256