257 lines
9.3 KiB
C
257 lines
9.3 KiB
C
/*
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LUFA Library
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Copyright (C) Dean Camera, 2012.
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dean [at] fourwalledcubicle [dot] com
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www.lufa-lib.org
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*/
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/*
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Copyright 2012 Dean Camera (dean [at] fourwalledcubicle [dot] com)
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Permission to use, copy, modify, distribute, and sell this
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software and its documentation for any purpose is hereby granted
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without fee, provided that the above copyright notice appear in
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all copies and that both that the copyright notice and this
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permission notice and warranty disclaimer appear in supporting
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documentation, and that the name of the author not be used in
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advertising or publicity pertaining to distribution of the
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software without specific, written prior permission.
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The author disclaim all warranties with regard to this
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software, including all implied warranties of merchantability
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and fitness. In no event shall the author be liable for any
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special, indirect or consequential damages or any damages
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whatsoever resulting from loss of use, data or profits, whether
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in an action of contract, negligence or other tortious action,
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arising out of or in connection with the use or performance of
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this software.
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*/
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/** \file
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* \brief SPI Peripheral Driver (AVR8)
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*
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* On-chip SPI driver for the 8-bit AVR microcontrollers.
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*
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* \note This file should not be included directly. It is automatically included as needed by the SPI driver
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* dispatch header located in LUFA/Drivers/Peripheral/SPI.h.
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*/
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/** \ingroup Group_SPI
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* \defgroup Group_SPI_AVR8 SPI Peripheral Driver (AVR8)
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*
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* \section Sec_ModDescription Module Description
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* Driver for the hardware SPI port available on most 8-bit AVR microcontroller models. This
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* module provides an easy to use driver for the setup and transfer of data over the
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* AVR's SPI port.
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*
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* \note This file should not be included directly. It is automatically included as needed by the SPI driver
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* dispatch header located in LUFA/Drivers/Peripheral/SPI.h.
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*
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* \section Sec_ExampleUsage Example Usage
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* The following snippet is an example of how this module may be used within a typical
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* application.
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*
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* \code
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* // Initialize the SPI driver before first use
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* SPI_Init(SPI_SPEED_FCPU_DIV_2 | SPI_ORDER_MSB_FIRST | SPI_SCK_LEAD_FALLING |
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* SPI_SAMPLE_TRAILING | SPI_MODE_MASTER);
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*
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* // Send several bytes, ignoring the returned data
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* SPI_SendByte(0x01);
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* SPI_SendByte(0x02);
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* SPI_SendByte(0x03);
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*
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* // Receive several bytes, sending a dummy 0x00 byte each time
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* uint8_t Byte1 = SPI_ReceiveByte();
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* uint8_t Byte2 = SPI_ReceiveByte();
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* uint8_t Byte3 = SPI_ReceiveByte();
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*
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* // Send a byte, and store the received byte from the same transaction
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* uint8_t ResponseByte = SPI_TransferByte(0xDC);
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* \endcode
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*
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* @{
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*/
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#ifndef __SPI_AVR8_H__
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#define __SPI_AVR8_H__
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/* Includes: */
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#include "../../../Common/Common.h"
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/* Enable C linkage for C++ Compilers: */
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#if defined(__cplusplus)
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extern "C" {
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#endif
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/* Preprocessor Checks: */
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#if !defined(__INCLUDE_FROM_SPI_H)
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#error Do not include this file directly. Include LUFA/Drivers/Peripheral/SPI.h instead.
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#endif
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/* Private Interface - For use in library only: */
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#if !defined(__DOXYGEN__)
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/* Macros: */
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#define SPI_USE_DOUBLESPEED (1 << SPE)
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#endif
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/* Public Interface - May be used in end-application: */
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/* Macros: */
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/** \name SPI Prescaler Configuration Masks */
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//@{
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/** SPI prescaler mask for \ref SPI_Init(). Divides the system clock by a factor of 2. */
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#define SPI_SPEED_FCPU_DIV_2 SPI_USE_DOUBLESPEED
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/** SPI prescaler mask for \ref SPI_Init(). Divides the system clock by a factor of 4. */
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#define SPI_SPEED_FCPU_DIV_4 0
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/** SPI prescaler mask for \ref SPI_Init(). Divides the system clock by a factor of 8. */
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#define SPI_SPEED_FCPU_DIV_8 (SPI_USE_DOUBLESPEED | (1 << SPR0))
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/** SPI prescaler mask for \ref SPI_Init(). Divides the system clock by a factor of 16. */
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#define SPI_SPEED_FCPU_DIV_16 (1 << SPR0)
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/** SPI prescaler mask for \ref SPI_Init(). Divides the system clock by a factor of 32. */
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#define SPI_SPEED_FCPU_DIV_32 (SPI_USE_DOUBLESPEED | (1 << SPR1))
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/** SPI prescaler mask for \ref SPI_Init(). Divides the system clock by a factor of 64. */
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#define SPI_SPEED_FCPU_DIV_64 (SPI_USE_DOUBLESPEED | (1 << SPR1) | (1 << SPR0))
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/** SPI prescaler mask for \ref SPI_Init(). Divides the system clock by a factor of 128. */
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#define SPI_SPEED_FCPU_DIV_128 ((1 << SPR1) | (1 << SPR0))
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//@}
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/** \name SPI SCK Polarity Configuration Masks */
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//@{
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/** SPI clock polarity mask for \ref SPI_Init(). Indicates that the SCK should lead on the rising edge. */
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#define SPI_SCK_LEAD_RISING (0 << CPOL)
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/** SPI clock polarity mask for \ref SPI_Init(). Indicates that the SCK should lead on the falling edge. */
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#define SPI_SCK_LEAD_FALLING (1 << CPOL)
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//@}
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/** \name SPI Sample Edge Configuration Masks */
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//@{
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/** SPI data sample mode mask for \ref SPI_Init(). Indicates that the data should sampled on the leading edge. */
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#define SPI_SAMPLE_LEADING (0 << CPHA)
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/** SPI data sample mode mask for \ref SPI_Init(). Indicates that the data should be sampled on the trailing edge. */
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#define SPI_SAMPLE_TRAILING (1 << CPHA)
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//@}
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/** \name SPI Data Ordering Configuration Masks */
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//@{
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/** SPI data order mask for \ref SPI_Init(). Indicates that data should be shifted out MSB first. */
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#define SPI_ORDER_MSB_FIRST (0 << DORD)
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/** SPI data order mask for \ref SPI_Init(). Indicates that data should be shifted out LSB first. */
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#define SPI_ORDER_LSB_FIRST (1 << DORD)
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//@}
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/** \name SPI Mode Configuration Masks */
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//@{
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/** SPI mode mask for \ref SPI_Init(). Indicates that the SPI interface should be initialized into slave mode. */
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#define SPI_MODE_SLAVE (0 << MSTR)
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/** SPI mode mask for \ref SPI_Init(). Indicates that the SPI interface should be initialized into master mode. */
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#define SPI_MODE_MASTER (1 << MSTR)
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//@}
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/* Inline Functions: */
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/** Initializes the SPI subsystem, ready for transfers. Must be called before calling any other
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* SPI routines.
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*
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* \param[in] SPIOptions SPI Options, a mask consisting of one of each of the \c SPI_SPEED_*,
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* \c SPI_SCK_*, \c SPI_SAMPLE_*, \c SPI_ORDER_* and \c SPI_MODE_* masks.
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*/
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static inline void SPI_Init(const uint8_t SPIOptions)
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{
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/* Prevent high rise times on PB.0 (/SS) from forcing a change to SPI slave mode */
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DDRB |= (1 << 0);
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PORTB |= (1 << 0);
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DDRB |= ((1 << 1) | (1 << 2));
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DDRB &= ~(1 << 3);
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PORTB |= (1 << 3);
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if (SPIOptions & SPI_USE_DOUBLESPEED)
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SPSR |= (1 << SPI2X);
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else
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SPSR &= ~(1 << SPI2X);
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/* Switch /SS to input mode after configuration to allow for forced mode changes */
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DDRB &= ~(1 << 0);
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SPCR = ((1 << SPE) | SPIOptions);
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}
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/** Turns off the SPI driver, disabling and returning used hardware to their default configuration. */
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static inline void SPI_Disable(void)
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{
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DDRB &= ~((1 << 1) | (1 << 2));
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PORTB &= ~((1 << 0) | (1 << 3));
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SPCR = 0;
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SPSR = 0;
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}
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/** Retrieves the currently selected SPI mode, once the SPI interface has been configured.
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*
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* \return \ref SPI_MODE_MASTER if the interface is currently in SPI Master mode, \ref SPI_MODE_SLAVE otherwise
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*/
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static inline uint8_t SPI_GetCurrentMode(void) ATTR_ALWAYS_INLINE;
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static inline uint8_t SPI_GetCurrentMode(void)
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{
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return (SPCR & SPI_MODE_MASTER);
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}
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/** Sends and receives a byte through the SPI interface, blocking until the transfer is complete.
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*
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* \param[in] Byte Byte to send through the SPI interface.
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*
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* \return Response byte from the attached SPI device.
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*/
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static inline uint8_t SPI_TransferByte(const uint8_t Byte) ATTR_ALWAYS_INLINE;
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static inline uint8_t SPI_TransferByte(const uint8_t Byte)
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{
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SPDR = Byte;
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while (!(SPSR & (1 << SPIF)));
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return SPDR;
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}
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/** Sends a byte through the SPI interface, blocking until the transfer is complete. The response
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* byte sent to from the attached SPI device is ignored.
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*
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* \param[in] Byte Byte to send through the SPI interface.
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*/
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static inline void SPI_SendByte(const uint8_t Byte) ATTR_ALWAYS_INLINE;
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static inline void SPI_SendByte(const uint8_t Byte)
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{
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SPDR = Byte;
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while (!(SPSR & (1 << SPIF)));
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}
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/** Sends a dummy byte through the SPI interface, blocking until the transfer is complete. The response
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* byte from the attached SPI device is returned.
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*
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* \return The response byte from the attached SPI device.
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*/
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static inline uint8_t SPI_ReceiveByte(void) ATTR_ALWAYS_INLINE ATTR_WARN_UNUSED_RESULT;
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static inline uint8_t SPI_ReceiveByte(void)
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{
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SPDR = 0x00;
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while (!(SPSR & (1 << SPIF)));
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return SPDR;
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}
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/* Disable C linkage for C++ Compilers: */
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#if defined(__cplusplus)
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}
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#endif
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#endif
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/** @} */
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