Subversion Repositories openrisc

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

 *         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 "pit.h"

#include <board.h>

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

//         Global functions

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

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

/// Initialize the Periodic Interval Timer to generate a tick at the specified

/// period, given the current master clock frequency.

/// \param period  Period in µsecond.

/// \param pit_frequency  Master clock frequency in MHz.

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

void PIT_Init(unsigned int period, unsigned int pit_frequency)

{

    AT91C_BASE_PITC->PITC_PIMR = period? (period * pit_frequency + 8) >> 4 : 0;

    AT91C_BASE_PITC->PITC_PIMR |= AT91C_PITC_PITEN;

}

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

/// Set the Periodic Interval Value of the PIT.

/// \param piv  PIV value to set.

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

void PIT_SetPIV(unsigned int piv)

{

    AT91C_BASE_PITC->PITC_PIMR = (AT91C_BASE_PITC->PITC_PIMR & AT91C_PITC_PIV)

                                 | piv;

}

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

/// Enables the PIT if this is not already the case.

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

void PIT_Enable(void)

{

    AT91C_BASE_PITC->PITC_PIMR |= AT91C_PITC_PITEN;

}

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

/// Enable the PIT periodic interrupt.

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

void PIT_EnableIT(void)

{

    AT91C_BASE_PITC->PITC_PIMR |= AT91C_PITC_PITIEN;

}

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

/// Disables the PIT periodic interrupt.

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

void PIT_DisableIT(void)

{

    AT91C_BASE_PITC->PITC_PIMR &= ~AT91C_PITC_PITIEN;

}

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

/// Returns the value of the PIT mode register.

/// \return PIT_MR value.

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

unsigned int PIT_GetMode(void)

{

    return AT91C_BASE_PITC->PITC_PIMR;

}

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

/// Returns the value of the PIT status register, clearing it as a side effect.

/// \return PIT_SR value.

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

unsigned int PIT_GetStatus(void)

{

    return AT91C_BASE_PITC->PITC_PISR;

}

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

/// Returns the value of the PIT Image Register, to read PICNT and CPIV without

/// clearing the current values.

/// \return PIT_PIIR value.

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

unsigned int PIT_GetPIIR(void)

{

    return AT91C_BASE_PITC->PITC_PIIR;

}

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

/// Returns the value of the PIT Value Register, clearing it as a side effect.

/// \return PIT_PIVR value.

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

unsigned int PIT_GetPIVR(void)

{

    return AT91C_BASE_PITC->PITC_PIVR;

}