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[/] [openrisc/] [trunk/] [rtos/] [freertos-6.1.1/] [Demo/] [CORTEX_AT91SAM3U256_IAR/] [AT91Lib/] [peripherals/] [spi/] [spi.c] - Rev 604
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/* ---------------------------------------------------------------------------- * ATMEL Microcontroller Software Support * ---------------------------------------------------------------------------- * Copyright (c) 2008, 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. * * 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. * ---------------------------------------------------------------------------- */ //------------------------------------------------------------------------------ // Headers //------------------------------------------------------------------------------ #include "spi.h" //------------------------------------------------------------------------------ // Exported functions //------------------------------------------------------------------------------ //------------------------------------------------------------------------------ /// Enables a SPI peripheral /// \param spi Pointer to an AT91S_SPI instance. //------------------------------------------------------------------------------ void SPI_Enable(AT91S_SPI *spi) { spi->SPI_CR = AT91C_SPI_SPIEN; } //------------------------------------------------------------------------------ /// Disables a SPI peripheral. /// \param spi Pointer to an AT91S_SPI instance. //------------------------------------------------------------------------------ void SPI_Disable(AT91S_SPI *spi) { spi->SPI_CR = AT91C_SPI_SPIDIS; } //------------------------------------------------------------------------------ /// Configures a SPI peripheral as specified. The configuration can be computed /// using several macros (see "SPI configuration macros") and the constants /// defined in LibV3 (AT91C_SPI_*). /// \param spi Pointer to an AT91S_SPI instance. /// \param id Peripheral ID of the SPI. /// \param configuration Value of the SPI configuration register. //------------------------------------------------------------------------------ void SPI_Configure(AT91S_SPI *spi, unsigned int id, unsigned int configuration) { AT91C_BASE_PMC->PMC_PCER = 1 << id; spi->SPI_CR = AT91C_SPI_SPIDIS; // Execute a software reset of the SPI twice spi->SPI_CR = AT91C_SPI_SWRST; spi->SPI_CR = AT91C_SPI_SWRST; spi->SPI_MR = configuration; } //------------------------------------------------------------------------------ /// Configures a chip select of a SPI peripheral. The chip select configuration /// is computed using the definition provided by the LibV3 (AT91C_SPI_*). /// \param spi Pointer to an AT91S_SPI instance. /// \param npcs Chip select to configure (1, 2, 3 or 4). /// \param configuration Desired chip select configuration. //------------------------------------------------------------------------------ void SPI_ConfigureNPCS(AT91S_SPI *spi, unsigned int npcs, unsigned int configuration) { spi->SPI_CSR[npcs] = configuration; } //------------------------------------------------------------------------------ /// 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 AT91S_SPI instance. /// \param npcs Chip select of the component to address (1, 2, 3 or 4). /// \param data Word of data to send. //------------------------------------------------------------------------------ void SPI_Write(AT91S_SPI *spi, unsigned int npcs, unsigned short data) { // Discard contents of RDR register //volatile unsigned int discard = spi->SPI_RDR; // Send data while ((spi->SPI_SR & AT91C_SPI_TXEMPTY) == 0); spi->SPI_TDR = data | SPI_PCS(npcs); while ((spi->SPI_SR & AT91C_SPI_TDRE) == 0); } //------------------------------------------------------------------------------ /// Sends the contents of buffer through a SPI peripheral, using the PDC to /// take care of the transfer. /// \param spi Pointer to an AT91S_SPI instance. /// \param buffer Data buffer to send. /// \param length Length of the data buffer. //------------------------------------------------------------------------------ unsigned char SPI_WriteBuffer(AT91S_SPI *spi, void *buffer, unsigned int length) { // Check if first bank is free if (spi->SPI_TCR == 0) { spi->SPI_TPR = (unsigned int) buffer; spi->SPI_TCR = length; spi->SPI_PTCR = AT91C_PDC_TXTEN; return 1; } // Check if second bank is free else if (spi->SPI_TNCR == 0) { spi->SPI_TNPR = (unsigned int) buffer; spi->SPI_TNCR = length; return 1; } // No free banks return 0; } //------------------------------------------------------------------------------ /// Returns 1 if there is no pending write operation on the SPI; otherwise /// returns 0. /// \param pSpi Pointer to an AT91S_SPI instance. //------------------------------------------------------------------------------ unsigned char SPI_IsFinished(AT91S_SPI *pSpi) { return ((pSpi->SPI_SR & AT91C_SPI_TXEMPTY) != 0); } //------------------------------------------------------------------------------ /// 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 AT91S_SPI instance. //------------------------------------------------------------------------------ unsigned short SPI_Read(AT91S_SPI *spi) { while ((spi->SPI_SR & AT91C_SPI_RDRF) == 0); return spi->SPI_RDR & 0xFFFF; } //------------------------------------------------------------------------------ /// 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 AT91S_SPI instance. /// \param buffer Data buffer to store incoming bytes. /// \param length Length in bytes of the data buffer. //------------------------------------------------------------------------------ unsigned char SPI_ReadBuffer(AT91S_SPI *spi, void *buffer, unsigned int length) { // Check if the first bank is free if (spi->SPI_RCR == 0) { spi->SPI_RPR = (unsigned int) buffer; spi->SPI_RCR = length; spi->SPI_PTCR = AT91C_PDC_RXTEN; return 1; } // Check if second bank is free else if (spi->SPI_RNCR == 0) { spi->SPI_RNPR = (unsigned int) buffer; spi->SPI_RNCR = length; return 1; } // No free bank return 0; }
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