/* ---------------------------------------------------------------------------- | |
* SAM Software Package License | |
* ---------------------------------------------------------------------------- | |
* Copyright (c) 2011, Atmel Corporation | |
* | |
* All rights reserved. | |
* | |
* Redistribution and use in source and binary forms, with or without | |
* modification, are permitted provided that the following conditions are met: | |
* | |
* - Redistributions of source code must retain the above copyright notice, | |
* this list of conditions and the disclaimer below. | |
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* Atmel's name may not be used to endorse or promote products derived from | |
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* DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR | |
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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. | |
* -# 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_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 SPI chip select. | |
* | |
* \param spi Pointer to an SPI instance. | |
* \param cS Chip select of NPSCx. | |
*/ | |
extern void SPI_ChipSelect( Spi* spi, uint8_t cS) | |
{ | |
spi->SPI_MR |= SPI_MR_PCS_Msk ; | |
spi->SPI_MR &= ~(SPI_MR_PCS ( cS )) ; | |
} | |
/** | |
* \brief Configures SPI Mode Register. | |
* | |
* \param spi Pointer to an SPI instance. | |
* \param configuration Value of the SPI mode register. | |
*/ | |
extern void SPI_SetMode( Spi* spi, | |
uint32_t dwConfiguration ) | |
{ | |
spi->SPI_MR = dwConfiguration ; | |
} | |
/** | |
* \brief Configures SPI to release last used CS line. | |
* | |
* \param spi Pointer to an SPI instance. | |
*/ | |
extern void SPI_ReleaseCS( Spi* spi ) | |
{ | |
spi->SPI_CR = SPI_CR_LASTXFER ; | |
} | |
/** | |
* \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 Configures a chip select active mode of a SPI peripheral. | |
* | |
* \param spi Pointer to an SPI instance. | |
* \param dwNpcs Chip select to configure (0, 1, 2 or 3). | |
* \param bReleaseOnLast CS controlled by last transfer. | |
* SPI_ReleaseCS() is used to release CS. | |
*/ | |
void SPI_ConfigureCSMode( Spi* spi, uint32_t dwNpcs, uint32_t bReleaseOnLast ) | |
{ | |
if (bReleaseOnLast) { | |
spi->SPI_CSR[dwNpcs] |= SPI_CSR_CSAAT; | |
} else { | |
spi->SPI_CSR[dwNpcs] &= ~SPI_CSR_CSAAT; | |
} | |
} | |
/** | |
* \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 read 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 Sends last 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_WriteLast( 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 ) | SPI_TDR_LASTXFER ; | |
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) ; | |
} | |