/* ---------------------------------------------------------------------------- | |
* ATMEL Microcontroller Software Support | |
* ---------------------------------------------------------------------------- | |
* Copyright (c) 2009, Atmel Corporation | |
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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 "pmc.h" | |
#include "spi.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_EnablePeripheral( 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) ; | |
} | |
/** | |
* \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 ; | |
} | |