From 044ad7c3987460ede48ff27afd6bdb0ca05a0432 Mon Sep 17 00:00:00 2001 From: Harald Welte Date: Mon, 4 Jul 2011 20:52:54 +0200 Subject: import at91lib from at91lib_20100901_softpack_1_9_v_1_0_svn_v15011 it's sad to see that atmel doesn't publish their svn repo or has a centralized location or even puts proper version/release info into the library itself --- peripherals/spi/spi.c | 194 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 194 insertions(+) create mode 100644 peripherals/spi/spi.c (limited to 'peripherals/spi/spi.c') diff --git a/peripherals/spi/spi.c b/peripherals/spi/spi.c new file mode 100644 index 0000000..16eba71 --- /dev/null +++ b/peripherals/spi/spi.c @@ -0,0 +1,194 @@ +/* ---------------------------------------------------------------------------- + * 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) +{ +#if !defined(CHIP_SPI_DMA) + // 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; + } +#endif + // 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) +{ +#if !defined(CHIP_SPI_DMA) + // 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; + } +#endif + // No free bank + return 0; +} + -- cgit v1.2.3