Subversion Repositories openrisc_2011-10-31

/* ----------------------------------------------------------------------------

 *         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 "ssc.h"

#include <utility/trace.h>

//------------------------------------------------------------------------------

//         Exported functions

//------------------------------------------------------------------------------

//------------------------------------------------------------------------------

/// Configures a SSC peripheral. If the divided clock is not used, the master

/// clock frequency can be set to 0.

/// \note The emitter and transmitter are disabled by this function.

/// \param ssc  Pointer to an AT91S_SSC instance.

/// \param id  Peripheral ID of the SSC.

//------------------------------------------------------------------------------

void SSC_Configure(AT91S_SSC *ssc,

                          unsigned int id,

                          unsigned int bitRate,

                          unsigned int masterClock)

{

    // Enable SSC peripheral clock

    AT91C_BASE_PMC->PMC_PCER = 1 << id;

    // Reset, disable receiver & transmitter

    ssc->SSC_CR = AT91C_SSC_RXDIS | AT91C_SSC_TXDIS | AT91C_SSC_SWRST;

    ssc->SSC_PTCR = AT91C_PDC_RXTDIS | AT91C_PDC_TXTDIS;

    // Configure clock frequency

    if (bitRate != 0) {

        ssc->SSC_CMR = masterClock / (2 * bitRate);

    }

    else {

        ssc->SSC_CMR = 0;

    }

}

//------------------------------------------------------------------------------

/// Configures the transmitter of a SSC peripheral. Several macros can be used

/// to compute the values of the Transmit Clock Mode Register (TCMR) and the

/// Transmit Frame Mode Register (TFMR) (see "SSC configuration macros").

/// \param ssc  Pointer to a AT91S_SSC instance.

/// \param tcmr  Transmit Clock Mode Register value.

/// \param tfmr  Transmit Frame Mode Register value.

//------------------------------------------------------------------------------

void SSC_ConfigureTransmitter(AT91S_SSC *ssc,

                                     unsigned int tcmr,

                                     unsigned int tfmr)

{

    ssc->SSC_TCMR = tcmr;

    ssc->SSC_TFMR = tfmr;

}

//------------------------------------------------------------------------------

/// Configures the receiver of a SSC peripheral. Several macros can be used

/// to compute the values of the Receive Clock Mode Register (TCMR) and the

/// Receive Frame Mode Register (TFMR) (see "SSC configuration macros").

/// \param ssc  Pointer to a AT91S_SSC instance.

/// \param rcmr  Receive Clock Mode Register value.

/// \param rfmr  Receive Frame Mode Register value.

//------------------------------------------------------------------------------

void SSC_ConfigureReceiver(AT91S_SSC *ssc,

                                  unsigned int rcmr,

                                  unsigned int rfmr)

{

    ssc->SSC_RCMR = rcmr;

    ssc->SSC_RFMR = rfmr;

}

//------------------------------------------------------------------------------

/// Enables the transmitter of a SSC peripheral.

/// \param ssc  Pointer to an AT91S_SSC instance.

//------------------------------------------------------------------------------

void SSC_EnableTransmitter(AT91S_SSC *ssc)

{

    ssc->SSC_CR = AT91C_SSC_TXEN;

}

//------------------------------------------------------------------------------

/// Disables the transmitter of a SSC peripheral.

/// \param ssc  Pointer to an AT91S_SSC instance.

//------------------------------------------------------------------------------

void SSC_DisableTransmitter(AT91S_SSC *ssc)

{

    ssc->SSC_CR = AT91C_SSC_TXDIS;

}

//------------------------------------------------------------------------------

/// Enables the receiver of a SSC peripheral.

/// \param ssc  Pointer to an AT91S_SSC instance.

//------------------------------------------------------------------------------

void SSC_EnableReceiver(AT91S_SSC *ssc)

{

    ssc->SSC_CR = AT91C_SSC_RXEN;

}

//------------------------------------------------------------------------------

/// Disables the receiver of a SSC peripheral.

/// \param ssc  Pointer to an AT91S_SSC instance.

//------------------------------------------------------------------------------

void SSC_DisableReceiver(AT91S_SSC *ssc)

{

    ssc->SSC_CR = AT91C_SSC_RXDIS;

}

//------------------------------------------------------------------------------

/// Enables one or more interrupt sources of a SSC peripheral.

/// \param ssc  Pointer to an AT91S_SSC instance.

/// \param sources  Interrupt sources to enable.

//------------------------------------------------------------------------------

void SSC_EnableInterrupts(AT91S_SSC *ssc, unsigned int sources)

{

    ssc->SSC_IER = sources;

}

//------------------------------------------------------------------------------

/// Disables one or more interrupt sources of a SSC peripheral.

/// \param ssc  Pointer to an AT91S_SSC instance.

/// \param sources  Interrupt source to disable.

//------------------------------------------------------------------------------

void SSC_DisableInterrupts(AT91S_SSC *ssc, unsigned int sources)

{

    ssc->SSC_IDR = sources;

}

//------------------------------------------------------------------------------

/// Sends one data frame through a SSC peripheral. If another frame is currently

/// being sent, this function waits for the previous transfer to complete.

/// \param ssc  Pointer to an AT91S_SSC instance.

/// \param frame  Data frame to send.

//------------------------------------------------------------------------------

void SSC_Write(AT91S_SSC *ssc, unsigned int frame)

{

    while ((ssc->SSC_SR & AT91C_SSC_TXRDY) == 0);

    ssc->SSC_THR = frame;

}

//------------------------------------------------------------------------------

/// Sends the contents of a data buffer a SSC peripheral, using the PDC. Returns

/// true if the buffer has been queued for transmission; otherwise returns

/// false.

/// \param ssc  Pointer to an AT91S_SSC instance.

/// \param buffer  Data buffer to send.

/// \param length  Size of the data buffer.

//------------------------------------------------------------------------------

unsigned char SSC_WriteBuffer(AT91S_SSC *ssc,

                                     void *buffer,

                                     unsigned int length)

{

    // Check if first bank is free

    if (ssc->SSC_TCR == 0) {

        ssc->SSC_TPR = (unsigned int) buffer;

        ssc->SSC_TCR = length;

        ssc->SSC_PTCR = AT91C_PDC_TXTEN;

        return 1;

    }

    // Check if second bank is free

    else if (ssc->SSC_TNCR == 0) {

        ssc->SSC_TNPR = (unsigned int) buffer;

        ssc->SSC_TNCR = length;

        return 1;

    }

    // No free banks

    return 0;

}

//------------------------------------------------------------------------------

/// Waits until one frame is received on a SSC peripheral, and returns it.

/// \param ssc  Pointer to an AT91S_SSC instance.

//------------------------------------------------------------------------------

unsigned int SSC_Read(AT91S_SSC *ssc)

{

    while ((ssc->SSC_SR & AT91C_SSC_RXRDY) == 0);

    return ssc->SSC_RHR;

}

//------------------------------------------------------------------------------

/// Reads data coming from a SSC peripheral receiver and stores it into the

/// provided buffer. Returns true if the buffer has been queued for reception;

/// otherwise returns false.

/// \param ssc  Pointer to an AT91S_SSC instance.

/// \param buffer  Data buffer used for reception.

/// \param length  Size in bytes of the data buffer.

//------------------------------------------------------------------------------

unsigned char SSC_ReadBuffer(AT91S_SSC *ssc,

                                    void *buffer,

                                    unsigned int length)

{

    // Check if the first bank is free

    if (ssc->SSC_RCR == 0) {

        ssc->SSC_RPR = (unsigned int) buffer;

        ssc->SSC_RCR = length;

        ssc->SSC_PTCR = AT91C_PDC_RXTEN;

        return 1;

    }

    // Check if second bank is free

    else if (ssc->SSC_RNCR == 0) {

        ssc->SSC_RNPR = (unsigned int) buffer;

        ssc->SSC_RNCR = length;

        return 1;

    }

    // No free bank

    return 0;

}