Arduino/hardware/sam/system/libsam/source/acc.c

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 *         ATMEL Microcontroller Software Support
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/** \addtogroup acc_module Working with ACC
 * The ACC driver provides the interface to configure and use the ACC peripheral.\n
 *
 * It applies comparison on two inputs and gives a compare output.
 *
 * To Enable a ACC Comparison,the user has to follow these few steps:
 * <ul>
 * <li> Enable ACC peripheral clock by setting the corresponding bit in PMC_PCER1
 *      (PMC Peripheral Clock Enable Register 1)
 * </li>
 * <li> Reset the controller by asserting ACC_CR_SWRST in ACC_CR(ACC Control Register)
 </li>
 * <li> Configure the mode as following steps:  </li>
 * -#   Select inputs for SELMINUS and SELPLUS in ACC_MR (ACC Mode Register).
 * -#   Enable Analog Comparator by setting ACEN in ACC_MR.
 * -#   Configure Edge Type to detect different compare output.
 * </li>
 * <li> Wait until the automatic mask period expires by polling MASK bit in
 *      ACC_ISR.
 * </ul>
 *
 * For more accurate information, please look at the ACC section of the
 * Datasheet.
 *
 * Related files :\n
 * \ref acc.c\n
 * \ref acc.h\n
 */
/*@{*/
/*@}*/
/**
 * \file
 *
 * Implementation of Analog Comparator Controller (ACC).
 *
 */
/*----------------------------------------------------------------------------
 *        Headers
 *----------------------------------------------------------------------------*/

#include "chip.h"

/*----------------------------------------------------------------------------
 *        Exported functions
 *----------------------------------------------------------------------------*/

/**
 * \brief Initialize the ACC controller
 *
 * \param pAcc Pointer to an Acc instance.
 * \param idAcc ACC identifier
 * \param ucSelplus input connected to inp, 0~7
 * \param ucSelminus input connected to inm,0~7
 * \param wAc_en Analog comprator enabled/disabled
 * \param wEdge CF flag triggering mode
 * \param wInvert INVert comparator output,use pattern defined in the device header file
 */
extern void ACC_Configure( Acc *pAcc, uint8_t idAcc, uint8_t ucSelplus, uint8_t ucSelminus,
                           uint16_t wAc_en, uint16_t wEdge, uint16_t wInvert )
{
    /* Enable peripheral clock*/
    PMC->PMC_PCER1 = 1 << (idAcc - 32) ;

    /*  Reset the controller */
    pAcc->ACC_CR |= ACC_CR_SWRST ;

    /*  Write to the MR register */
    ACC_CfgModeReg( pAcc,
                    ( (ucSelplus<<ACC_MR_SELPLUS_Pos) & ACC_MR_SELPLUS_Msk ) |
                    ( (ucSelminus<<ACC_MR_SELMINUS_Pos) & ACC_MR_SELMINUS_Msk ) |
                    ( (wAc_en<<8) & ACC_MR_ACEN ) |
                    ( (wEdge<<ACC_MR_EDGETYP_Pos) & ACC_MR_EDGETYP_Msk ) |
                    ( (wInvert<<12) & ACC_MR_INV ) ) ;
    /* set hysteresis and current option*/
    pAcc->ACC_ACR = (ACC_ACR_ISEL_HISP | ((0x01 << ACC_ACR_HYST_Pos) & ACC_ACR_HYST_Msk));

    /* Automatic Output Masking Period*/
    while ( pAcc->ACC_ISR & (uint32_t)ACC_ISR_MASK ) ;
}

/**
 * Return the Channel Converted Data
 * \param pAcc Pointer to an Acc instance.
 * \param selplus input applied on ACC SELPLUS
 * \param selminus input applied on ACC SELMINUS
 */
extern void ACC_SetComparisionPair( Acc *pAcc, uint8_t ucSelplus, uint8_t ucSelminus )
{
    uint32_t dwTemp ;

    assert( ucSelplus < 8 && ucSelminus < 8 ) ;

    dwTemp = pAcc->ACC_MR ;

    pAcc->ACC_MR = dwTemp & (uint32_t) ((~ACC_MR_SELMINUS_Msk) & (~ACC_MR_SELPLUS_Msk));

    pAcc->ACC_MR |= ( ((ucSelplus << ACC_MR_SELPLUS_Pos) & ACC_MR_SELPLUS_Msk) |
                      ((ucSelminus << ACC_MR_SELMINUS_Pos) & ACC_MR_SELMINUS_Msk) ) ;

}
/**
 * Return Comparison Result
 * \param pAcc Pointer to an Acc instance.
 * \param status value of ACC_ISR
 */
extern uint32_t ACC_GetComparisionResult( Acc *pAcc, uint32_t dwStatus )
{
    uint32_t dwTemp = pAcc->ACC_MR ;

    if ( (dwTemp & ACC_MR_INV) == ACC_MR_INV )
    {
        if ( dwStatus & ACC_ISR_SCO )
        {
            return 0 ; /* inn>inp*/
        }
        else
        {
            return 1 ;/* inp>inn*/
        }
    }
    else
    {
        if ( dwStatus & ACC_ISR_SCO )
        {
            return 1 ; /* inp>inn*/
        }
        else
        {
            return 0 ;/* inn>inp*/
        }
    }
}