244 lines
9.8 KiB
C
244 lines
9.8 KiB
C
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/* ----------------------------------------------------------------------------
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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 "ssc.h"
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#include <utility/trace.h>
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//------------------------------------------------------------------------------
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// Exported functions
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//------------------------------------------------------------------------------
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//------------------------------------------------------------------------------
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/// Configures a SSC peripheral. If the divided clock is not used, the master
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/// clock frequency can be set to 0.
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/// \note The emitter and transmitter are disabled by this function.
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/// \param ssc Pointer to an AT91S_SSC instance.
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/// \param id Peripheral ID of the SSC.
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//------------------------------------------------------------------------------
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void SSC_Configure(AT91S_SSC *ssc,
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unsigned int id,
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unsigned int bitRate,
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unsigned int masterClock)
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{
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// Enable SSC peripheral clock
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AT91C_BASE_PMC->PMC_PCER = 1 << id;
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// Reset, disable receiver & transmitter
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ssc->SSC_CR = AT91C_SSC_RXDIS | AT91C_SSC_TXDIS | AT91C_SSC_SWRST;
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ssc->SSC_PTCR = AT91C_PDC_RXTDIS | AT91C_PDC_TXTDIS;
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// Configure clock frequency
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if (bitRate != 0) {
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ssc->SSC_CMR = masterClock / (2 * bitRate);
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}
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else {
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ssc->SSC_CMR = 0;
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}
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}
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//------------------------------------------------------------------------------
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/// Configures the transmitter of a SSC peripheral. Several macros can be used
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/// to compute the values of the Transmit Clock Mode Register (TCMR) and the
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/// Transmit Frame Mode Register (TFMR) (see "SSC configuration macros").
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/// \param ssc Pointer to a AT91S_SSC instance.
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/// \param tcmr Transmit Clock Mode Register value.
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/// \param tfmr Transmit Frame Mode Register value.
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//------------------------------------------------------------------------------
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void SSC_ConfigureTransmitter(AT91S_SSC *ssc,
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unsigned int tcmr,
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unsigned int tfmr)
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{
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ssc->SSC_TCMR = tcmr;
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ssc->SSC_TFMR = tfmr;
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}
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//------------------------------------------------------------------------------
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/// Configures the receiver of a SSC peripheral. Several macros can be used
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/// to compute the values of the Receive Clock Mode Register (TCMR) and the
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/// Receive Frame Mode Register (TFMR) (see "SSC configuration macros").
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/// \param ssc Pointer to a AT91S_SSC instance.
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/// \param rcmr Receive Clock Mode Register value.
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/// \param rfmr Receive Frame Mode Register value.
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//------------------------------------------------------------------------------
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void SSC_ConfigureReceiver(AT91S_SSC *ssc,
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unsigned int rcmr,
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unsigned int rfmr)
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{
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ssc->SSC_RCMR = rcmr;
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ssc->SSC_RFMR = rfmr;
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}
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//------------------------------------------------------------------------------
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/// Enables the transmitter of a SSC peripheral.
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/// \param ssc Pointer to an AT91S_SSC instance.
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//------------------------------------------------------------------------------
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void SSC_EnableTransmitter(AT91S_SSC *ssc)
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{
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ssc->SSC_CR = AT91C_SSC_TXEN;
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}
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//------------------------------------------------------------------------------
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/// Disables the transmitter of a SSC peripheral.
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/// \param ssc Pointer to an AT91S_SSC instance.
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//------------------------------------------------------------------------------
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void SSC_DisableTransmitter(AT91S_SSC *ssc)
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{
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ssc->SSC_CR = AT91C_SSC_TXDIS;
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}
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//------------------------------------------------------------------------------
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/// Enables the receiver of a SSC peripheral.
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/// \param ssc Pointer to an AT91S_SSC instance.
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//------------------------------------------------------------------------------
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void SSC_EnableReceiver(AT91S_SSC *ssc)
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{
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ssc->SSC_CR = AT91C_SSC_RXEN;
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}
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//------------------------------------------------------------------------------
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/// Disables the receiver of a SSC peripheral.
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/// \param ssc Pointer to an AT91S_SSC instance.
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//------------------------------------------------------------------------------
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void SSC_DisableReceiver(AT91S_SSC *ssc)
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{
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ssc->SSC_CR = AT91C_SSC_RXDIS;
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}
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//------------------------------------------------------------------------------
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/// Enables one or more interrupt sources of a SSC peripheral.
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/// \param ssc Pointer to an AT91S_SSC instance.
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/// \param sources Interrupt sources to enable.
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//------------------------------------------------------------------------------
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void SSC_EnableInterrupts(AT91S_SSC *ssc, unsigned int sources)
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{
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ssc->SSC_IER = sources;
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}
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//------------------------------------------------------------------------------
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/// Disables one or more interrupt sources of a SSC peripheral.
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/// \param ssc Pointer to an AT91S_SSC instance.
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/// \param sources Interrupt source to disable.
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//------------------------------------------------------------------------------
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void SSC_DisableInterrupts(AT91S_SSC *ssc, unsigned int sources)
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{
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ssc->SSC_IDR = sources;
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}
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//------------------------------------------------------------------------------
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/// Sends one data frame through a SSC peripheral. If another frame is currently
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/// being sent, this function waits for the previous transfer to complete.
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/// \param ssc Pointer to an AT91S_SSC instance.
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/// \param frame Data frame to send.
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//------------------------------------------------------------------------------
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void SSC_Write(AT91S_SSC *ssc, unsigned int frame)
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{
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while ((ssc->SSC_SR & AT91C_SSC_TXRDY) == 0);
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ssc->SSC_THR = frame;
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}
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//------------------------------------------------------------------------------
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/// Sends the contents of a data buffer a SSC peripheral, using the PDC. Returns
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/// true if the buffer has been queued for transmission; otherwise returns
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/// false.
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/// \param ssc Pointer to an AT91S_SSC instance.
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/// \param buffer Data buffer to send.
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/// \param length Size of the data buffer.
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//------------------------------------------------------------------------------
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unsigned char SSC_WriteBuffer(AT91S_SSC *ssc,
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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 (ssc->SSC_TCR == 0) {
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ssc->SSC_TPR = (unsigned int) buffer;
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ssc->SSC_TCR = length;
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ssc->SSC_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 (ssc->SSC_TNCR == 0) {
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ssc->SSC_TNPR = (unsigned int) buffer;
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ssc->SSC_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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/// Waits until one frame is received on a SSC peripheral, and returns it.
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/// \param ssc Pointer to an AT91S_SSC instance.
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//------------------------------------------------------------------------------
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unsigned int SSC_Read(AT91S_SSC *ssc)
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{
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while ((ssc->SSC_SR & AT91C_SSC_RXRDY) == 0);
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return ssc->SSC_RHR;
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}
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//------------------------------------------------------------------------------
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/// Reads data coming from a SSC peripheral receiver and stores it into the
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/// provided buffer. Returns true if the buffer has been queued for reception;
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/// otherwise returns false.
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/// \param ssc Pointer to an AT91S_SSC instance.
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/// \param buffer Data buffer used for reception.
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/// \param length Size in bytes of the data buffer.
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//------------------------------------------------------------------------------
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unsigned char SSC_ReadBuffer(AT91S_SSC *ssc,
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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 (ssc->SSC_RCR == 0) {
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ssc->SSC_RPR = (unsigned int) buffer;
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ssc->SSC_RCR = length;
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ssc->SSC_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 (ssc->SSC_RNCR == 0) {
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ssc->SSC_RNPR = (unsigned int) buffer;
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ssc->SSC_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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