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SPI Peripheral Driver (AVR8)

Functions

static void SPI_Disable (void)
 
static uint8_t SPI_GetCurrentMode (void) ATTR_ALWAYS_INLINE
 
static void SPI_Init (const uint8_t SPIOptions)
 
static uint8_t SPI_ReceiveByte (void) ATTR_ALWAYS_INLINE ATTR_WARN_UNUSED_RESULT
 
static void SPI_SendByte (const uint8_t Byte) ATTR_ALWAYS_INLINE
 
static uint8_t SPI_TransferByte (const uint8_t Byte) ATTR_ALWAYS_INLINE
 

SPI Prescaler Configuration Masks

#define SPI_SPEED_FCPU_DIV_2   SPI_USE_DOUBLESPEED
 
#define SPI_SPEED_FCPU_DIV_4   0
 
#define SPI_SPEED_FCPU_DIV_8   (SPI_USE_DOUBLESPEED | (1 << SPR0))
 
#define SPI_SPEED_FCPU_DIV_16   (1 << SPR0)
 
#define SPI_SPEED_FCPU_DIV_32   (SPI_USE_DOUBLESPEED | (1 << SPR1))
 
#define SPI_SPEED_FCPU_DIV_64   (SPI_USE_DOUBLESPEED | (1 << SPR1) | (1 << SPR0))
 
#define SPI_SPEED_FCPU_DIV_128   ((1 << SPR1) | (1 << SPR0))
 

SPI SCK Polarity Configuration Masks

#define SPI_SCK_LEAD_RISING   (0 << CPOL)
 
#define SPI_SCK_LEAD_FALLING   (1 << CPOL)
 

SPI Sample Edge Configuration Masks

#define SPI_SAMPLE_LEADING   (0 << CPHA)
 
#define SPI_SAMPLE_TRAILING   (1 << CPHA)
 

SPI Data Ordering Configuration Masks

#define SPI_ORDER_MSB_FIRST   (0 << DORD)
 
#define SPI_ORDER_LSB_FIRST   (1 << DORD)
 

SPI Mode Configuration Masks

#define SPI_MODE_SLAVE   (0 << MSTR)
 
#define SPI_MODE_MASTER   (1 << MSTR)
 

Detailed Description

Module Description

Driver for the hardware SPI port available on most 8-bit AVR microcontroller models. This module provides an easy to use driver for the setup and transfer of data over the AVR's SPI port.

Note
This file should not be included directly. It is automatically included as needed by the SPI driver dispatch header located in LUFA/Drivers/Peripheral/SPI.h.

Example Usage

The following snippet is an example of how this module may be used within a typical application.

* // Initialize the SPI driver before first use
*
* // 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);
*

Macro Definition Documentation

#define SPI_MODE_MASTER   (1 << MSTR)

SPI mode mask for SPI_Init(). Indicates that the SPI interface should be initialized into master mode.

#define SPI_MODE_SLAVE   (0 << MSTR)

SPI mode mask for SPI_Init(). Indicates that the SPI interface should be initialized into slave mode.

#define SPI_ORDER_LSB_FIRST   (1 << DORD)

SPI data order mask for SPI_Init(). Indicates that data should be shifted out LSB first.

#define SPI_ORDER_MSB_FIRST   (0 << DORD)

SPI data order mask for SPI_Init(). Indicates that data should be shifted out MSB first.

#define SPI_SAMPLE_LEADING   (0 << CPHA)

SPI data sample mode mask for SPI_Init(). Indicates that the data should sampled on the leading edge.

#define SPI_SAMPLE_TRAILING   (1 << CPHA)

SPI data sample mode mask for SPI_Init(). Indicates that the data should be sampled on the trailing edge.

#define SPI_SCK_LEAD_FALLING   (1 << CPOL)

SPI clock polarity mask for SPI_Init(). Indicates that the SCK should lead on the falling edge.

#define SPI_SCK_LEAD_RISING   (0 << CPOL)

SPI clock polarity mask for SPI_Init(). Indicates that the SCK should lead on the rising edge.

#define SPI_SPEED_FCPU_DIV_128   ((1 << SPR1) | (1 << SPR0))

SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 128.

#define SPI_SPEED_FCPU_DIV_16   (1 << SPR0)

SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 16.

#define SPI_SPEED_FCPU_DIV_2   SPI_USE_DOUBLESPEED

SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 2.

#define SPI_SPEED_FCPU_DIV_32   (SPI_USE_DOUBLESPEED | (1 << SPR1))

SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 32.

#define SPI_SPEED_FCPU_DIV_4   0

SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 4.

#define SPI_SPEED_FCPU_DIV_64   (SPI_USE_DOUBLESPEED | (1 << SPR1) | (1 << SPR0))

SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 64.

#define SPI_SPEED_FCPU_DIV_8   (SPI_USE_DOUBLESPEED | (1 << SPR0))

SPI prescaler mask for SPI_Init(). Divides the system clock by a factor of 8.

Function Documentation

static void SPI_Disable ( void  )
inlinestatic

Turns off the SPI driver, disabling and returning used hardware to their default configuration.

static uint8_t SPI_GetCurrentMode ( void  )
inlinestatic

Retrieves the currently selected SPI mode, once the SPI interface has been configured.

Returns
SPI_MODE_MASTER if the interface is currently in SPI Master mode, SPI_MODE_SLAVE otherwise
static void SPI_Init ( const uint8_t  SPIOptions)
inlinestatic

Initializes the SPI subsystem, ready for transfers. Must be called before calling any other SPI routines.

Parameters
[in]SPIOptionsSPI Options, a mask consisting of one of each of the SPI_SPEED_*, SPI_SCK_*, SPI_SAMPLE_*, SPI_ORDER_* and SPI_MODE_* masks.
static uint8_t SPI_ReceiveByte ( void  )
inlinestatic

Sends a dummy byte through the SPI interface, blocking until the transfer is complete. The response byte from the attached SPI device is returned.

Returns
The response byte from the attached SPI device.
static void SPI_SendByte ( const uint8_t  Byte)
inlinestatic

Sends a byte through the SPI interface, blocking until the transfer is complete. The response byte sent to from the attached SPI device is ignored.

Parameters
[in]ByteByte to send through the SPI interface.
static uint8_t SPI_TransferByte ( const uint8_t  Byte)
inlinestatic

Sends and receives a byte through the SPI interface, blocking until the transfer is complete.

Parameters
[in]ByteByte to send through the SPI interface.
Returns
Response byte from the attached SPI device.