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 "usart.h"

#include <utility/trace.h>

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

//         Exported functions

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

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

/// Configures an USART peripheral with the specified parameters.

/// \param usart  Pointer to the USART peripheral to configure.

/// \param mode  Desired value for the USART mode register (see the datasheet).

/// \param baudrate  Baudrate at which the USART should operate (in Hz).

/// \param masterClock  Frequency of the system master clock (in Hz).

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

void USART_Configure(AT91S_USART *usart,

                            unsigned int mode,

                            unsigned int baudrate,

                            unsigned int masterClock)

{

    // Reset and disable receiver & transmitter

    usart->US_CR = AT91C_US_RSTRX | AT91C_US_RSTTX

                   | AT91C_US_RXDIS | AT91C_US_TXDIS;

    // Configure mode

    usart->US_MR = mode;

    // Configure baudrate

    // Asynchronous, no oversampling

    if (((mode & AT91C_US_SYNC) == 0)

        && ((mode & AT91C_US_OVER) == 0)) {

        usart->US_BRGR = (masterClock / baudrate) / 16;

    }

    // TODO other modes

}

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

/// Enables or disables the transmitter of an USART peripheral.

/// \param usart  Pointer to an USART peripheral

/// \param enabled  If true, the transmitter is enabled; otherwise it is

///                 disabled.

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

void USART_SetTransmitterEnabled(AT91S_USART *usart,

                                        unsigned char enabled)

{

    if (enabled) {

        usart->US_CR = AT91C_US_TXEN;

    }

    else {

        usart->US_CR = AT91C_US_TXDIS;

    }

}

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

/// Enables or disables the receiver of an USART peripheral

/// \param usart  Pointer to an USART peripheral

/// \param enabled  If true, the receiver is enabled; otherwise it is disabled.

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

void USART_SetReceiverEnabled(AT91S_USART *usart,

                                     unsigned char enabled)

{

    if (enabled) {

        usart->US_CR = AT91C_US_RXEN;

    }

    else {

        usart->US_CR = AT91C_US_RXDIS;

    }

}

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

/// Sends one packet of data through the specified USART peripheral. This

/// function operates synchronously, so it only returns when the data has been

/// actually sent.

/// \param usart  Pointer to an USART peripheral.

/// \param data  Data to send including 9nth bit and sync field if necessary (in

///              the same format as the US_THR register in the datasheet).

/// \param timeOut  Time out value (0 = no timeout).

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

void USART_Write(

    AT91S_USART *usart,

    unsigned short data,

    volatile unsigned int timeOut)

{

    if (timeOut == 0) {

        while ((usart->US_CSR & AT91C_US_TXEMPTY) == 0);

    }

    else {

        while ((usart->US_CSR & AT91C_US_TXEMPTY) == 0) {

            if (timeOut == 0) {

                trace_LOG(trace_ERROR, "-E- USART_Write: Timed out.\n\r");

                return;

            }

            timeOut--;

        }

    }

    usart->US_THR = data;

}

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

/// Sends the contents of a data buffer through the specified USART peripheral.

/// This function returns immediately (1 if the buffer has been queued, 0

/// otherwise); poll the ENDTX and TXBUFE bits of the USART status register

/// to check for the transfer completion.

/// \param usart  Pointer to an USART peripheral.

/// \param buffer  Pointer to the data buffer to send.

/// \param size  Size of the data buffer (in bytes).

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

unsigned char USART_WriteBuffer(

    AT91S_USART *usart,

    void *buffer,

    unsigned int size)

{

    // Check if the first PDC bank is free

    if ((usart->US_TCR == 0) && (usart->US_TNCR == 0)) {

        usart->US_TPR = (unsigned int) buffer;

        usart->US_TCR = size;

        usart->US_PTCR = AT91C_PDC_TXTEN;

        return 1;

    }

    // Check if the second PDC bank is free

    else if (usart->US_TNCR == 0) {

        usart->US_TNPR = (unsigned int) buffer;

        usart->US_TNCR = size;

        return 1;

    }

    else {

        return 0;

    }

}

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

/// Reads and return a packet of data on the specified USART peripheral. This

/// function operates asynchronously, so it waits until some data has been

/// received.

/// \param usart  Pointer to an USART peripheral.

/// \param timeOut  Time out value (0 -> no timeout).

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

unsigned short USART_Read(

    AT91S_USART *usart,

    volatile unsigned int timeOut)

{

    if (timeOut == 0) {

        while ((usart->US_CSR & AT91C_US_RXRDY) == 0);

    }

    else {

        while ((usart->US_CSR & AT91C_US_RXRDY) == 0) {

            if (timeOut == 0) {

                trace_LOG(trace_ERROR, "-E- USART_Read: Timed out.\n\r");

                return 0;

            }

            timeOut--;

        }

    }

    return usart->US_RHR;

}

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

/// Reads data from an USART peripheral, filling the provided buffer until it

/// becomes full. This function returns immediately with 1 if the buffer has

/// been queued for transmission; otherwise 0.

/// \param usart  Pointer to an USART peripheral.

/// \param buffer  Pointer to the buffer where the received data will be stored.

/// \param size  Size of the data buffer (in bytes).

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

unsigned char USART_ReadBuffer(AT91S_USART *usart,

                                      void *buffer,

                                      unsigned int size)

{

    // Check if the first PDC bank is free

    if ((usart->US_RCR == 0) && (usart->US_RNCR == 0)) {

        usart->US_RPR = (unsigned int) buffer;

        usart->US_RCR = size;

        usart->US_PTCR = AT91C_PDC_RXTEN;

        return 1;

    }

    // Check if the second PDC bank is free

    else if (usart->US_RNCR == 0) {

        usart->US_RNPR = (unsigned int) buffer;

        usart->US_RNCR = size;

        return 1;

    }

    else {

        return 0;

    }

}

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

/// Returns 1 if some data has been received and can be read from an USART;

/// otherwise returns 0.

/// \param usart  Pointer to an AT91S_USART instance.

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

unsigned char USART_IsDataAvailable(AT91S_USART *usart)

{

    if ((usart->US_CSR & AT91C_US_RXRDY) != 0) {

        return 1;

    }

    else {

        return 0;

    }

}