/* ---------------------------------------------------------------------------- */ /* Atmel Microcontroller Software Support */ /* SAM Software Package License */ /* ---------------------------------------------------------------------------- */ /* Copyright (c) 2015, Atmel Corporation */ /* */ /* All rights reserved. */ /* */ /* Redistribution and use in source and binary forms, with or without */ /* modification, are permitted provided that the following condition is met: */ /* */ /* - Redistributions of source code must retain the above copyright notice, */ /* this list of conditions and the disclaimer below. */ /* */ /* Atmel's name may not be used to endorse or promote products derived from */ /* this software without specific prior written permission. */ /* */ /* DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR */ /* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF */ /* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE */ /* DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT, */ /* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT */ /* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, */ /* OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF */ /* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING */ /* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, */ /* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /* ---------------------------------------------------------------------------- */ /** \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 /*---------------------------------------------------------------------------- * 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); }