mirror of
https://github.com/FreeRTOS/FreeRTOS-Kernel.git
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189 lines
7.8 KiB
C
189 lines
7.8 KiB
C
/* ----------------------------------------------------------------------------
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* ATMEL Microcontroller Software Support
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* ----------------------------------------------------------------------------
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* Copyright (c) 2008, Atmel Corporation
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*
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* - Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the disclaimer below.
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*
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* Atmel's name may not be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
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* DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
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* OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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* ----------------------------------------------------------------------------
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*/
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//------------------------------------------------------------------------------
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// Headers
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//------------------------------------------------------------------------------
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#include "spi.h"
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//------------------------------------------------------------------------------
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// Exported functions
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//------------------------------------------------------------------------------
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//------------------------------------------------------------------------------
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/// Enables a SPI peripheral
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/// \param spi Pointer to an AT91S_SPI instance.
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//------------------------------------------------------------------------------
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void SPI_Enable(AT91S_SPI *spi)
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{
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spi->SPI_CR = AT91C_SPI_SPIEN;
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}
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//------------------------------------------------------------------------------
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/// Disables a SPI peripheral.
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/// \param spi Pointer to an AT91S_SPI instance.
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//------------------------------------------------------------------------------
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void SPI_Disable(AT91S_SPI *spi)
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{
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spi->SPI_CR = AT91C_SPI_SPIDIS;
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}
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//------------------------------------------------------------------------------
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/// Configures a SPI peripheral as specified. The configuration can be computed
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/// using several macros (see "SPI configuration macros") and the constants
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/// defined in LibV3 (AT91C_SPI_*).
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/// \param spi Pointer to an AT91S_SPI instance.
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/// \param id Peripheral ID of the SPI.
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/// \param configuration Value of the SPI configuration register.
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//------------------------------------------------------------------------------
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void SPI_Configure(AT91S_SPI *spi,
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unsigned int id,
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unsigned int configuration)
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{
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AT91C_BASE_PMC->PMC_PCER = 1 << id;
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spi->SPI_CR = AT91C_SPI_SPIDIS | AT91C_SPI_SWRST;
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spi->SPI_MR = configuration;
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}
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//------------------------------------------------------------------------------
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/// Configures a chip select of a SPI peripheral. The chip select configuration
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/// is computed using the definition provided by the LibV3 (AT91C_SPI_*).
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/// \param spi Pointer to an AT91S_SPI instance.
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/// \param npcs Chip select to configure (1, 2, 3 or 4).
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/// \param configuration Desired chip select configuration.
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//------------------------------------------------------------------------------
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void SPI_ConfigureNPCS(AT91S_SPI *spi,
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unsigned int npcs,
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unsigned int configuration)
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{
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spi->SPI_CSR[npcs] = configuration;
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}
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//------------------------------------------------------------------------------
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/// Sends data through a SPI peripheral. If the SPI is configured to use a fixed
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/// peripheral select, the npcs value is meaningless. Otherwise, it identifies
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/// the component which shall be addressed.
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/// \param spi Pointer to an AT91S_SPI instance.
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/// \param npcs Chip select of the component to address (1, 2, 3 or 4).
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/// \param data Word of data to send.
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//------------------------------------------------------------------------------
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void SPI_Write(AT91S_SPI *spi, unsigned int npcs, unsigned short data)
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{
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// Discard contents of RDR register
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//volatile unsigned int discard = spi->SPI_RDR;
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// Send data
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while ((spi->SPI_SR & AT91C_SPI_TXEMPTY) == 0);
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spi->SPI_TDR = data | SPI_PCS(npcs);
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while ((spi->SPI_SR & AT91C_SPI_TDRE) == 0);
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}
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//------------------------------------------------------------------------------
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/// Sends the contents of buffer through a SPI peripheral, using the PDC to
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/// take care of the transfer.
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/// \param spi Pointer to an AT91S_SPI instance.
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/// \param buffer Data buffer to send.
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/// \param length Length of the data buffer.
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//------------------------------------------------------------------------------
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unsigned char SPI_WriteBuffer(AT91S_SPI *spi,
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void *buffer,
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unsigned int length)
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{
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// Check if first bank is free
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if (spi->SPI_TCR == 0) {
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spi->SPI_TPR = (unsigned int) buffer;
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spi->SPI_TCR = length;
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spi->SPI_PTCR = AT91C_PDC_TXTEN;
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return 1;
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}
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// Check if second bank is free
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else if (spi->SPI_TNCR == 0) {
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spi->SPI_TNPR = (unsigned int) buffer;
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spi->SPI_TNCR = length;
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return 1;
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}
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// No free banks
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return 0;
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}
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//------------------------------------------------------------------------------
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/// Returns 1 if there is no pending write operation on the SPI; otherwise
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/// returns 0.
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/// \param pSpi Pointer to an AT91S_SPI instance.
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//------------------------------------------------------------------------------
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unsigned char SPI_IsFinished(AT91S_SPI *pSpi)
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{
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return ((pSpi->SPI_SR & AT91C_SPI_TXEMPTY) != 0);
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}
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//------------------------------------------------------------------------------
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/// Reads and returns the last word of data received by a SPI peripheral. This
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/// method must be called after a successful SPI_Write call.
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/// \param spi Pointer to an AT91S_SPI instance.
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//------------------------------------------------------------------------------
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unsigned short SPI_Read(AT91S_SPI *spi)
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{
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while ((spi->SPI_SR & AT91C_SPI_RDRF) == 0);
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return spi->SPI_RDR & 0xFFFF;
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}
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//------------------------------------------------------------------------------
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/// Reads data from a SPI peripheral until the provided buffer is filled. This
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/// method does NOT need to be called after SPI_Write or SPI_WriteBuffer.
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/// \param spi Pointer to an AT91S_SPI instance.
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/// \param buffer Data buffer to store incoming bytes.
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/// \param length Length in bytes of the data buffer.
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//------------------------------------------------------------------------------
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unsigned char SPI_ReadBuffer(AT91S_SPI *spi,
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void *buffer,
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unsigned int length)
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{
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// Check if the first bank is free
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if (spi->SPI_RCR == 0) {
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spi->SPI_RPR = (unsigned int) buffer;
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spi->SPI_RCR = length;
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spi->SPI_PTCR = AT91C_PDC_RXTEN;
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return 1;
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}
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// Check if second bank is free
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else if (spi->SPI_RNCR == 0) {
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spi->SPI_RNPR = (unsigned int) buffer;
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spi->SPI_RNCR = length;
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return 1;
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}
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// No free bank
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return 0;
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}
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