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https://github.com/arduino/Arduino.git
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326 lines
8.7 KiB
C
326 lines
8.7 KiB
C
/*
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%atmel_license%
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*/
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/** \addtogroup spi_module Working with SPI
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* The SPI driver provides the interface to configure and use the SPI
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* peripheral.
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*
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* The Serial Peripheral Interface (SPI) circuit is a synchronous serial
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* data link that provides communication with external devices in Master
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* or Slave Mode.
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*
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* To use the SPI, the user has to follow these few steps:
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* -# Enable the SPI pins required by the application (see pio.h).
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* -# Configure the SPI using the \ref SPI_Configure(). This enables the
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* peripheral clock. The mode register is loaded with the given value.
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* -# Configure all the necessary chip selects with \ref SPI_ConfigureNPCS().
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* -# Enable the SPI by calling \ref SPI_Enable().
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* -# Send/receive data using \ref SPI_Write() and \ref SPI_Read(). Note that \ref SPI_Read()
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* must be called after \ref SPI_Write() to retrieve the last value read.
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* -# Send/receive data using the PDC with the \ref SPI_WriteBuffer() and
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* \ref SPI_ReadBuffer() functions.
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* -# Disable the SPI by calling \ref SPI_Disable().
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*
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* For more accurate information, please look at the SPI section of the
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* Datasheet.
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*
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* Related files :\n
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* \ref spi.c\n
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* \ref spi.h.\n
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*/
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/*@{*/
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/*@}*/
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/**
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* \file
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*
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* Implementation of Serial Peripheral Interface (SPI) controller.
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*
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*/
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/*----------------------------------------------------------------------------
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* Headers
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*----------------------------------------------------------------------------*/
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#include "chip.h"
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#include <stdint.h>
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/*----------------------------------------------------------------------------
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* Exported functions
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*----------------------------------------------------------------------------*/
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/**
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* \brief Enables a SPI peripheral.
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*
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* \param spi Pointer to an Spi instance.
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*/
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extern void SPI_Enable( Spi* spi )
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{
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spi->SPI_CR = SPI_CR_SPIEN ;
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}
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/**
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* \brief Disables a SPI peripheral.
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*
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* \param spi Pointer to an Spi instance.
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*/
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extern void SPI_Disable( Spi* spi )
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{
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spi->SPI_CR = SPI_CR_SPIDIS ;
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}
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/**
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* \brief Enables one or more interrupt sources of a SPI peripheral.
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*
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* \param spi Pointer to an Spi instance.
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* \param sources Bitwise OR of selected interrupt sources.
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*/
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extern void SPI_EnableIt( Spi* spi, uint32_t dwSources )
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{
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spi->SPI_IER = dwSources ;
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}
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/**
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* \brief Disables one or more interrupt sources of a SPI peripheral.
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*
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* \param spi Pointer to an Spi instance.
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* \param sources Bitwise OR of selected interrupt sources.
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*/
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extern void SPI_DisableIt( Spi* spi, uint32_t dwSources )
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{
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spi->SPI_IDR = dwSources ;
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}
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/**
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* \brief Configures a SPI peripheral as specified. The configuration can be computed
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* using several macros (see \ref spi_configuration_macros).
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*
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* \param spi Pointer to an Spi instance.
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* \param id Peripheral ID of the SPI.
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* \param configuration Value of the SPI configuration register.
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*/
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extern void SPI_Configure( Spi* spi, uint32_t dwId, uint32_t dwConfiguration )
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{
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PMC_EnablePeripheral( dwId ) ;
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spi->SPI_CR = SPI_CR_SPIDIS ;
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/* Execute a software reset of the SPI twice */
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spi->SPI_CR = SPI_CR_SWRST ;
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spi->SPI_CR = SPI_CR_SWRST ;
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spi->SPI_MR = dwConfiguration ;
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}
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/**
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* \brief Configures a chip select of a SPI peripheral. The chip select configuration
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* is computed using several macros (see \ref spi_configuration_macros).
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*
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* \param spi Pointer to an Spi instance.
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* \param npcs Chip select to configure (0, 1, 2 or 3).
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* \param configuration Desired chip select configuration.
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*/
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void SPI_ConfigureNPCS( Spi* spi, uint32_t dwNpcs, uint32_t dwConfiguration )
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{
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spi->SPI_CSR[dwNpcs] = dwConfiguration ;
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}
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/**
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* \brief Get the current status register of the given SPI peripheral.
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* \note This resets the internal value of the status register, so further
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* read may yield different values.
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* \param spi Pointer to a Spi instance.
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* \return SPI status register.
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*/
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extern uint32_t SPI_GetStatus( Spi* spi )
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{
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return spi->SPI_SR ;
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}
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/**
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* \brief Reads and returns the last word of data received by a SPI peripheral. This
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* method must be called after a successful SPI_Write call.
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*
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* \param spi Pointer to an Spi instance.
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*
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* \return readed data.
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*/
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extern uint32_t SPI_Read( Spi* spi )
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{
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while ( (spi->SPI_SR & SPI_SR_RDRF) == 0 ) ;
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return spi->SPI_RDR & 0xFFFF ;
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}
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/**
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* \brief Sends data through a SPI peripheral. If the SPI is configured to use a fixed
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* peripheral select, the npcs value is meaningless. Otherwise, it identifies
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* the component which shall be addressed.
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*
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* \param spi Pointer to an Spi instance.
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* \param npcs Chip select of the component to address (0, 1, 2 or 3).
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* \param data Word of data to send.
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*/
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extern void SPI_Write( Spi* spi, uint32_t dwNpcs, uint16_t wData )
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{
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/* Send data */
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while ( (spi->SPI_SR & SPI_SR_TXEMPTY) == 0 ) ;
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spi->SPI_TDR = wData | SPI_PCS( dwNpcs ) ;
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while ( (spi->SPI_SR & SPI_SR_TDRE) == 0 ) ;
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}
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/**
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* \brief Check if SPI transfer finish.
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*
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* \param spi Pointer to an Spi instance.
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*
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* \return Returns 1 if there is no pending write operation on the SPI; otherwise
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* returns 0.
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*/
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extern uint32_t SPI_IsFinished( Spi* spi )
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{
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return ((spi->SPI_SR & SPI_SR_TXEMPTY) != 0) ;
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}
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/**
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* \brief Enable Spi PDC transmit
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* \param spi Pointer to an Spi instance.
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*/
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extern void SPI_PdcEnableTx( Spi* spi )
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{
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spi->SPI_PTCR = SPI_PTCR_TXTEN ;
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}
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/**
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* \brief Disable Spi PDC transmit
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* \param spi Pointer to an Spi instance.
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*/
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extern void SPI_PdcDisableTx( Spi* spi )
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{
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spi->SPI_PTCR = SPI_PTCR_TXTDIS ;
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}
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/**
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* \brief Enable Spi PDC receive
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* \param spi Pointer to an Spi instance.
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*/
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extern void SPI_PdcEnableRx( Spi* spi )
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{
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spi->SPI_PTCR = SPI_PTCR_RXTEN ;
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}
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/**
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* \brief Disable Spi PDC receive
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* \param spi Pointer to an Spi instance.
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*/
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extern void SPI_PdcDisableRx( Spi* spi )
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{
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spi->SPI_PTCR = SPI_PTCR_RXTDIS ;
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}
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/**
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* \brief Set PDC transmit and next transmit buffer address and size.
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*
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* \param spi Pointer to an Spi instance.
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* \param txBuf PDC transmit buffer address.
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* \param txCount Length in bytes of the transmit buffer.
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* \param txNextBuf PDC next transmit buffer address.
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* \param txNextCount Length in bytes of the next transmit buffer.
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*/
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extern void SPI_PdcSetTx( Spi* spi, void* pvTxBuf, uint32_t dwTxCount, void* pvTxNextBuf, uint32_t dwTxNextCount )
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{
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spi->SPI_TPR = (uint32_t)pvTxBuf ;
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spi->SPI_TCR = dwTxCount ;
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spi->SPI_TNPR = (uint32_t)pvTxNextBuf ;
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spi->SPI_TNCR = dwTxNextCount ;
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}
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/**
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* \brief Set PDC receive and next receive buffer address and size.
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*
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* \param spi Pointer to an Spi instance.
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* \param rxBuf PDC receive buffer address.
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* \param rxCount Length in bytes of the receive buffer.
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* \param rxNextBuf PDC next receive buffer address.
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* \param rxNextCount Length in bytes of the next receive buffer.
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*/
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extern void SPI_PdcSetRx( Spi* spi, void* pvRxBuf, uint32_t dwRxCount, void* pvRxNextBuf, uint32_t dwRxNextCount )
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{
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spi->SPI_RPR = (uint32_t)pvRxBuf ;
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spi->SPI_RCR = dwRxCount ;
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spi->SPI_RNPR = (uint32_t)pvRxNextBuf ;
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spi->SPI_RNCR = dwRxNextCount ;
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}
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/**
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* \brief Sends the contents of buffer through a SPI peripheral, using the PDC to
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* take care of the transfer.
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*
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* \param spi Pointer to an Spi instance.
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* \param buffer Data buffer to send.
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* \param length Length of the data buffer.
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*/
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extern uint32_t SPI_WriteBuffer( Spi* spi, void* pvBuffer, uint32_t dwLength )
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{
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/* Check if first bank is free */
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if ( spi->SPI_TCR == 0 )
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{
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spi->SPI_TPR = (uint32_t)pvBuffer ;
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spi->SPI_TCR = dwLength ;
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spi->SPI_PTCR = PERIPH_PTCR_TXTEN ;
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return 1 ;
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}
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/* Check if second bank is free */
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else
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{
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if ( spi->SPI_TNCR == 0 )
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{
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spi->SPI_TNPR = (uint32_t)pvBuffer ;
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spi->SPI_TNCR = dwLength ;
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return 1 ;
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}
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}
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/* No free banks */
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return 0 ;
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}
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/**
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* \brief Reads data from a SPI peripheral until the provided buffer is filled. This
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* method does NOT need to be called after SPI_Write or SPI_WriteBuffer.
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*
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* \param spi Pointer to an Spi instance.
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* \param buffer Data buffer to store incoming bytes.
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* \param length Length in bytes of the data buffer.
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*/
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extern uint32_t SPI_ReadBuffer( Spi* spi, void *pvBuffer, uint32_t dwLength )
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{
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/* Check if the first bank is free */
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if ( spi->SPI_RCR == 0 )
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{
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spi->SPI_RPR = (uint32_t)pvBuffer ;
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spi->SPI_RCR = dwLength ;
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spi->SPI_PTCR = PERIPH_PTCR_RXTEN ;
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return 1 ;
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}
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/* Check if second bank is free */
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else
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{
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if ( spi->SPI_RNCR == 0 )
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{
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spi->SPI_RNPR = (uint32_t)pvBuffer ;
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spi->SPI_RNCR = dwLength ;
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return 1 ;
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}
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}
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/* No free bank */
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return 0 ;
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}
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