/* ----------------------------------------------------------------------------
* SAM Software Package License
* ----------------------------------------------------------------------------
* Copyright (c) 2011-2012, Atmel Corporation
*
* All rights reserved.
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* modification, are permitted provided that the following condition is met:
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/** \addtogroup spi_module Working with SPI
* The SPI driver provides the interface to configure and use the SPI
* peripheral.
*
* The Serial Peripheral Interface (SPI) circuit is a synchronous serial
* data link that provides communication with external devices in Master
* or Slave Mode.
*
* To use the SPI, the user has to follow these few steps:
* -# Enable the SPI pins required by the application (see pio.h).
* -# Configure the SPI using the \ref SPI_Configure(). This enables the
* peripheral clock. The mode register is loaded with the given value.
* -# Configure all the necessary chip selects with \ref SPI_ConfigureNPCS().
* -# Enable the SPI by calling \ref SPI_Enable().
* -# Send/receive data using \ref SPI_Write() and \ref SPI_Read(). Note that \ref SPI_Read()
* must be called after \ref SPI_Write() to retrieve the last value read.
* -# Send/receive data using the PDC with the \ref SPI_WriteBuffer() and
* \ref SPI_ReadBuffer() functions.
* -# Disable the SPI by calling \ref SPI_Disable().
*
* For more accurate information, please look at the SPI section of the
* Datasheet.
*
* Related files :\n
* \ref spi.c\n
* \ref spi.h.\n
*/
/*@{*/
/*@}*/
/**
* \file
*
* Implementation of Serial Peripheral Interface (SPI) controller.
*
*/
/*----------------------------------------------------------------------------
* Headers
*----------------------------------------------------------------------------*/
#include "chip.h"
#include <stdint.h>
/*----------------------------------------------------------------------------
* Exported functions
*----------------------------------------------------------------------------*/
/**
* \brief Enables a SPI peripheral.
*
* \param spi Pointer to an Spi instance.
*/
extern void SPI_Enable( Spi* spi )
{
spi->SPI_CR = SPI_CR_SPIEN ;
}
/**
* \brief Disables a SPI peripheral.
*
* \param spi Pointer to an Spi instance.
*/
extern void SPI_Disable( Spi* spi )
{
spi->SPI_CR = SPI_CR_SPIDIS ;
}
/**
* \brief Enables one or more interrupt sources of a SPI peripheral.
*
* \param spi Pointer to an Spi instance.
* \param sources Bitwise OR of selected interrupt sources.
*/
extern void SPI_EnableIt( Spi* spi, uint32_t dwSources )
{
spi->SPI_IER = dwSources ;
}
/**
* \brief Disables one or more interrupt sources of a SPI peripheral.
*
* \param spi Pointer to an Spi instance.
* \param sources Bitwise OR of selected interrupt sources.
*/
extern void SPI_DisableIt( Spi* spi, uint32_t dwSources )
{
spi->SPI_IDR = dwSources ;
}
/**
* \brief Configures a SPI peripheral as specified. The configuration can be computed
* using several macros (see \ref spi_configuration_macros).
*
* \param spi Pointer to an Spi instance.
* \param id Peripheral ID of the SPI.
* \param configuration Value of the SPI configuration register.
*/
extern void SPI_Configure( Spi* spi, uint32_t dwId, uint32_t dwConfiguration )
{
pmc_enable_periph_clk( dwId ) ;
spi->SPI_CR = SPI_CR_SPIDIS ;
/* Execute a software reset of the SPI twice */
spi->SPI_CR = SPI_CR_SWRST ;
spi->SPI_CR = SPI_CR_SWRST ;
spi->SPI_MR = dwConfiguration ;
}
/**
* \brief Configures a chip select of a SPI peripheral. The chip select configuration
* is computed using several macros (see \ref spi_configuration_macros).
*
* \param spi Pointer to an Spi instance.
* \param npcs Chip select to configure (0, 1, 2 or 3).
* \param configuration Desired chip select configuration.
*/
void SPI_ConfigureNPCS( Spi* spi, uint32_t dwNpcs, uint32_t dwConfiguration )
{
spi->SPI_CSR[dwNpcs] = dwConfiguration ;
}
/**
* \brief Get the current status register of the given SPI peripheral.
* \note This resets the internal value of the status register, so further
* read may yield different values.
* \param spi Pointer to a Spi instance.
* \return SPI status register.
*/
extern uint32_t SPI_GetStatus( Spi* spi )
{
return spi->SPI_SR ;
}
/**
* \brief Reads and returns the last word of data received by a SPI peripheral. This
* method must be called after a successful SPI_Write call.
*
* \param spi Pointer to an Spi instance.
*
* \return readed data.
*/
extern uint32_t SPI_Read( Spi* spi )
{
while ( (spi->SPI_SR & SPI_SR_RDRF) == 0 ) ;
return spi->SPI_RDR & 0xFFFF ;
}
/**
* \brief Sends data through a SPI peripheral. If the SPI is configured to use a fixed
* peripheral select, the npcs value is meaningless. Otherwise, it identifies
* the component which shall be addressed.
*
* \param spi Pointer to an Spi instance.
* \param npcs Chip select of the component to address (0, 1, 2 or 3).
* \param data Word of data to send.
*/
extern void SPI_Write( Spi* spi, uint32_t dwNpcs, uint16_t wData )
{
/* Send data */
while ( (spi->SPI_SR & SPI_SR_TXEMPTY) == 0 ) ;
spi->SPI_TDR = wData | SPI_PCS( dwNpcs ) ;
while ( (spi->SPI_SR & SPI_SR_TDRE) == 0 ) ;
}
/**
* \brief Check if SPI transfer finish.
*
* \param spi Pointer to an Spi instance.
*
* \return Returns 1 if there is no pending write operation on the SPI; otherwise
* returns 0.
*/
extern uint32_t SPI_IsFinished( Spi* spi )
{
return ((spi->SPI_SR & SPI_SR_TXEMPTY) != 0) ;
}
#if (defined _SAM3S_) || (defined _SAM3S8_) || (defined _SAM3N_)
/**
* \brief Enable Spi PDC transmit
* \param spi Pointer to an Spi instance.
*/
extern void SPI_PdcEnableTx( Spi* spi )
{
spi->SPI_PTCR = SPI_PTCR_TXTEN ;
}
/**
* \brief Disable Spi PDC transmit
* \param spi Pointer to an Spi instance.
*/
extern void SPI_PdcDisableTx( Spi* spi )
{
spi->SPI_PTCR = SPI_PTCR_TXTDIS ;
}
/**
* \brief Enable Spi PDC receive
* \param spi Pointer to an Spi instance.
*/
extern void SPI_PdcEnableRx( Spi* spi )
{
spi->SPI_PTCR = SPI_PTCR_RXTEN ;
}
/**
* \brief Disable Spi PDC receive
* \param spi Pointer to an Spi instance.
*/
extern void SPI_PdcDisableRx( Spi* spi )
{
spi->SPI_PTCR = SPI_PTCR_RXTDIS ;
}
/**
* \brief Set PDC transmit and next transmit buffer address and size.
*
* \param spi Pointer to an Spi instance.
* \param txBuf PDC transmit buffer address.
* \param txCount Length in bytes of the transmit buffer.
* \param txNextBuf PDC next transmit buffer address.
* \param txNextCount Length in bytes of the next transmit buffer.
*/
extern void SPI_PdcSetTx( Spi* spi, void* pvTxBuf, uint32_t dwTxCount, void* pvTxNextBuf, uint32_t dwTxNextCount )
{
spi->SPI_TPR = (uint32_t)pvTxBuf ;
spi->SPI_TCR = dwTxCount ;
spi->SPI_TNPR = (uint32_t)pvTxNextBuf ;
spi->SPI_TNCR = dwTxNextCount ;
}
/**
* \brief Set PDC receive and next receive buffer address and size.
*
* \param spi Pointer to an Spi instance.
* \param rxBuf PDC receive buffer address.
* \param rxCount Length in bytes of the receive buffer.
* \param rxNextBuf PDC next receive buffer address.
* \param rxNextCount Length in bytes of the next receive buffer.
*/
extern void SPI_PdcSetRx( Spi* spi, void* pvRxBuf, uint32_t dwRxCount, void* pvRxNextBuf, uint32_t dwRxNextCount )
{
spi->SPI_RPR = (uint32_t)pvRxBuf ;
spi->SPI_RCR = dwRxCount ;
spi->SPI_RNPR = (uint32_t)pvRxNextBuf ;
spi->SPI_RNCR = dwRxNextCount ;
}
/**
* \brief Sends the contents of buffer through a SPI peripheral, using the PDC to
* take care of the transfer.
*
* \param spi Pointer to an Spi instance.
* \param buffer Data buffer to send.
* \param length Length of the data buffer.
*/
extern uint32_t SPI_WriteBuffer( Spi* spi, void* pvBuffer, uint32_t dwLength )
{
/* Check if first bank is free */
if ( spi->SPI_TCR == 0 )
{
spi->SPI_TPR = (uint32_t)pvBuffer ;
spi->SPI_TCR = dwLength ;
spi->SPI_PTCR = PERIPH_PTCR_TXTEN ;
return 1 ;
}
/* Check if second bank is free */
else
{
if ( spi->SPI_TNCR == 0 )
{
spi->SPI_TNPR = (uint32_t)pvBuffer ;
spi->SPI_TNCR = dwLength ;
return 1 ;
}
}
/* No free banks */
return 0 ;
}
/**
* \brief Reads data from a SPI peripheral until the provided buffer is filled. This
* method does NOT need to be called after SPI_Write or SPI_WriteBuffer.
*
* \param spi Pointer to an Spi instance.
* \param buffer Data buffer to store incoming bytes.
* \param length Length in bytes of the data buffer.
*/
extern uint32_t SPI_ReadBuffer( Spi* spi, void *pvBuffer, uint32_t dwLength )
{
/* Check if the first bank is free */
if ( spi->SPI_RCR == 0 )
{
spi->SPI_RPR = (uint32_t)pvBuffer ;
spi->SPI_RCR = dwLength ;
spi->SPI_PTCR = PERIPH_PTCR_RXTEN ;
return 1 ;
}
/* Check if second bank is free */
else
{
if ( spi->SPI_RNCR == 0 )
{
spi->SPI_RNPR = (uint32_t)pvBuffer ;
spi->SPI_RNCR = dwLength ;
return 1 ;
}
}
/* No free bank */
return 0 ;
}
#endif /* (defined _SAM3S_) || (defined _SAM3S8_) || (defined _SAM3N_) */