/*
LUFA Library
- Copyright (C) Dean Camera, 2011.
+ Copyright (C) Dean Camera, 2012.
dean [at] fourwalledcubicle [dot] com
www.lufa-lib.org
*/
/*
- Copyright 2011 Dean Camera (dean [at] fourwalledcubicle [dot] com)
+ Copyright 2012 Dean Camera (dean [at] fourwalledcubicle [dot] com)
Permission to use, copy, modify, distribute, and sell this
software and its documentation for any purpose is hereby granted
* application.
*
* \code
- * // Initialise the SPI driver before first use
+ * // Initialize the SPI driver before first use
* SPI_Init(SPI_SPEED_FCPU_DIV_2 | SPI_ORDER_MSB_FIRST | SPI_SCK_LEAD_FALLING |
* SPI_SAMPLE_TRAILING | SPI_MODE_MASTER);
- *
+ *
* // Send several bytes, ignoring the returned data
* SPI_SendByte(0x01);
* SPI_SendByte(0x02);
* SPI_SendByte(0x03);
- *
+ *
* // Receive several bytes, sending a dummy 0x00 byte each time
* uint8_t Byte1 = SPI_ReceiveByte();
* uint8_t Byte2 = SPI_ReceiveByte();
* uint8_t Byte3 = SPI_ReceiveByte();
- *
+ *
* // Send a byte, and store the received byte from the same transaction
* uint8_t ResponseByte = SPI_TransferByte(0xDC);
* \endcode
- *
+ *
* @{
*/
/* Macros: */
/** \name SPI Prescaler Configuration Masks */
//@{
- /** SPI prescaler mask for \c SPI_Init(). Divides the system clock by a factor of 2. */
+ /** SPI prescaler mask for \ref SPI_Init(). Divides the system clock by a factor of 2. */
#define SPI_SPEED_FCPU_DIV_2 SPI_USE_DOUBLESPEED
- /** SPI prescaler mask for \c SPI_Init(). Divides the system clock by a factor of 4. */
+ /** SPI prescaler mask for \ref SPI_Init(). Divides the system clock by a factor of 4. */
#define SPI_SPEED_FCPU_DIV_4 0
- /** SPI prescaler mask for \c SPI_Init(). Divides the system clock by a factor of 8. */
+ /** SPI prescaler mask for \ref SPI_Init(). Divides the system clock by a factor of 8. */
#define SPI_SPEED_FCPU_DIV_8 (SPI_USE_DOUBLESPEED | (1 << SPR0))
- /** SPI prescaler mask for \c SPI_Init(). Divides the system clock by a factor of 16. */
+ /** SPI prescaler mask for \ref SPI_Init(). Divides the system clock by a factor of 16. */
#define SPI_SPEED_FCPU_DIV_16 (1 << SPR0)
- /** SPI prescaler mask for \c SPI_Init(). Divides the system clock by a factor of 32. */
+ /** SPI prescaler mask for \ref SPI_Init(). Divides the system clock by a factor of 32. */
#define SPI_SPEED_FCPU_DIV_32 (SPI_USE_DOUBLESPEED | (1 << SPR1))
- /** SPI prescaler mask for \c SPI_Init(). Divides the system clock by a factor of 64. */
+ /** SPI prescaler mask for \ref SPI_Init(). Divides the system clock by a factor of 64. */
#define SPI_SPEED_FCPU_DIV_64 (SPI_USE_DOUBLESPEED | (1 << SPR1) | (1 << SPR0))
- /** SPI prescaler mask for \c SPI_Init(). Divides the system clock by a factor of 128. */
+ /** SPI prescaler mask for \ref SPI_Init(). Divides the system clock by a factor of 128. */
#define SPI_SPEED_FCPU_DIV_128 ((1 << SPR1) | (1 << SPR0))
//@}
/** \name SPI SCK Polarity Configuration Masks */
//@{
- /** SPI clock polarity mask for \c SPI_Init(). Indicates that the SCK should lead on the rising edge. */
+ /** SPI clock polarity mask for \ref SPI_Init(). Indicates that the SCK should lead on the rising edge. */
#define SPI_SCK_LEAD_RISING (0 << CPOL)
- /** SPI clock polarity mask for \c SPI_Init(). Indicates that the SCK should lead on the falling edge. */
+ /** SPI clock polarity mask for \ref SPI_Init(). Indicates that the SCK should lead on the falling edge. */
#define SPI_SCK_LEAD_FALLING (1 << CPOL)
//@}
/** \name SPI Sample Edge Configuration Masks */
//@{
- /** SPI data sample mode mask for \c SPI_Init(). Indicates that the data should sampled on the leading edge. */
+ /** SPI data sample mode mask for \ref SPI_Init(). Indicates that the data should sampled on the leading edge. */
#define SPI_SAMPLE_LEADING (0 << CPHA)
- /** SPI data sample mode mask for \c SPI_Init(). Indicates that the data should be sampled on the trailing edge. */
+ /** SPI data sample mode mask for \ref SPI_Init(). Indicates that the data should be sampled on the trailing edge. */
#define SPI_SAMPLE_TRAILING (1 << CPHA)
//@}
-
+
/** \name SPI Data Ordering Configuration Masks */
//@{
- /** SPI data order mask for \c SPI_Init(). Indicates that data should be shifted out MSB first. */
+ /** SPI data order mask for \ref SPI_Init(). Indicates that data should be shifted out MSB first. */
#define SPI_ORDER_MSB_FIRST (0 << DORD)
- /** SPI data order mask for \c SPI_Init(). Indicates that data should be shifted out MSB first. */
+ /** SPI data order mask for \ref SPI_Init(). Indicates that data should be shifted out LSB first. */
#define SPI_ORDER_LSB_FIRST (1 << DORD)
//@}
-
+
/** \name SPI Mode Configuration Masks */
//@{
- /** SPI mode mask for \c SPI_Init(). Indicates that the SPI interface should be initialized into slave mode. */
+ /** SPI mode mask for \ref SPI_Init(). Indicates that the SPI interface should be initialized into slave mode. */
#define SPI_MODE_SLAVE (0 << MSTR)
- /** SPI mode mask for \c SPI_Init(). Indicates that the SPI interface should be initialized into master mode. */
+ /** SPI mode mask for \ref SPI_Init(). Indicates that the SPI interface should be initialized into master mode. */
#define SPI_MODE_MASTER (1 << MSTR)
//@}
-
+
/* Inline Functions: */
- /** Initialises the SPI subsystem, ready for transfers. Must be called before calling any other
+ /** Initializes the SPI subsystem, ready for transfers. Must be called before calling any other
* SPI routines.
*
* \param[in] SPIOptions SPI Options, a mask consisting of one of each of the \c SPI_SPEED_*,
*/
static inline void SPI_Init(const uint8_t SPIOptions)
{
- DDRB |= ((1 << 1) | (1 << 2));
- DDRB &= ~((1 << 0) | (1 << 3));
- PORTB |= ((1 << 0) | (1 << 3));
+ /* Prevent high rise times on PB.0 (/SS) from forcing a change to SPI slave mode */
+ DDRB |= (1 << 0);
+ PORTB |= (1 << 0);
- SPCR = ((1 << SPE) | SPIOptions);
+ DDRB |= ((1 << 1) | (1 << 2));
+ DDRB &= ~(1 << 3);
+ PORTB |= (1 << 3);
if (SPIOptions & SPI_USE_DOUBLESPEED)
SPSR |= (1 << SPI2X);
else
SPSR &= ~(1 << SPI2X);
+
+ /* Switch /SS to input mode after configuration to allow for forced mode changes */
+ DDRB &= ~(1 << 0);
+
+ SPCR = ((1 << SPE) | SPIOptions);
}
/** Turns off the SPI driver, disabling and returning used hardware to their default configuration. */
SPSR = 0;
}
+ /** Retrieves the currently selected SPI mode, once the SPI interface has been configured.
+ *
+ * \return \ref SPI_MODE_MASTER if the interface is currently in SPI Master mode, \ref SPI_MODE_SLAVE otherwise
+ */
+ static inline uint8_t SPI_GetCurrentMode(void) ATTR_ALWAYS_INLINE;
+ static inline uint8_t SPI_GetCurrentMode(void)
+ {
+ return (SPCR & SPI_MODE_MASTER);
+ }
+
/** Sends and receives a byte through the SPI interface, blocking until the transfer is complete.
*
* \param[in] Byte Byte to send through the SPI interface.
projects / pub / USBasp.git / blobdiff