tpu_pta.c

mpc564 时钟中断 时钟中断

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/**************************************************************************/
/* FILE NAME: tpu_pta.c                       COPYRIGHT (c) MOTOROLA 2002 */
/* VERSION: 1.1                                   All Rights Reserved     */
/*                                                                        */
/* DESCRIPTION: This file contains the TPU PTA functions. These functions */
/* allow you to completely control TPU channels running the PTA function. */
/* They provide a simple interface requiring the minimum amount of        */
/* configuration by the user.                                             */
/*========================================================================*/
/* HISTORY           ORIGINAL AUTHOR: Stan Ostrum                         */
/*                                                                        */
/* REV      AUTHOR      DATE       DESCRIPTION OF CHANGE                  */
/* ---   -----------  ---------    ---------------------                  */
/* 1.0   Stan Ostrum  03 Sep 02    Initial version of function.           */
/* 1.1   Stan Ostrum  18 Sep 02    Revised after review.                  */
/**************************************************************************/
#include "tpu_pta.h"
#include "mpc500_util.h"

/*******************************************************************************
FUNCTION      : tpu_pta_init

PURPOSE       : To initialize a TPU channel to run the PTA function.

INPUT NOTES   : This function has 6 parameters:

                 *tpu     : This is a pointer to the TPU3 module to use. It is
                            of type TPU3_tag which is defined in m_tpu3.h
                 channel  : This is the channel number of the PTA function.
                 priority : This is the priority to assign to the PTA channel.
                            This parameter should be assigned a value of:
                            TPU_PRIORITY_HIGH, TPU_PRIORITY_MIDDLE or
                            TPU_PRIORITY_LOW.
                 timebase : This is the TPU timebase to use for measurement.
                            This parameter should be assigned a value of:
                            TPU_PTA_TCR1 or TPU_PTA_TCR2.
                 mode     : This is the PTA measurement mode.
                            This parameter should be assigned a value of:
                            TPU_PTA_HIGH_TIME_ACCUM, TPU_PTA_LOW_TIME_ACCUM,
                            TPU_PTA_PERIOD_ACCUM_RISE, or TPU_PTA_PERIOD_ACCUM_FALL
                 max_count: This is the number of pulses or periods to accumulate
                            before the measurement restarts. Range is 0 to 255.

RETURN NOTES  : none

WARNING       : The channel must be stopped before it is reconfigured. The
                function disables the channel but if it was currently
                being serviced it would continue. The delay for assigning the
                pram pointer may to enough, but depends on system loading.

*******************************************************************************/
void tpu_pta_init(struct TPU3_tag *tpu, UINT8 channel, UINT8 priority, \
                UINT8 timebase, UINT8 mode, UINT8 max_count)
{
    UINT16 channel_control;

    /* disable channel so it can be configured safely */
    tpu_disable( tpu, channel);

    /* select PTA function */
    tpu_func( tpu, channel, TPU_FUNCTION_PTA);

    /* initialize parameter RAM                                                */
    /* - initialize CHAN_CNTL and MAX_COUNT to their desired values            */
    /* - initialize PER_CNT, ACCUM, HIGH_WORD, and LOW_WORD to 0               */

    /* setup channel control word for desired measurement mode & TCR1 timebase */
    switch (mode)
        {
        case 0: TPU_PTA_HIGH_TIME_ACCUM;
        case 1: TPU_PTA_LOW_TIME_ACCUM;
                channel_control = TPU_PTA_HI_LOW_PW;
                break;
        case 2: TPU_PTA_PERIOD_ACCUM_RISE;
                channel_control = TPU_PTA_PERIOD_RISING;
                break;
        case 3: TPU_PTA_PERIOD_ACCUM_FALL;
                channel_control = TPU_PTA_PERIOD_FALLING;
                break;
        }

    /* set bit in channel control word for TCR2 operation */
    if (timebase == TPU_PTA_TCR2)
            channel_control = channel_control | 0x20;

    tpu->PARM.R[channel][TPU_PTA_CHAN_CNTL] = channel_control;
    tpu->PARM.R[channel][TPU_PTA_MAX_CNT_PRD_CNT] = (INT16) (max_count << 8);
    tpu->PARM.R[channel][TPU_PTA_LAST_TIME] = 0;
    tpu->PARM.R[channel][TPU_PTA_ACCUM] = 0;
    tpu->PARM.R[channel][TPU_PTA_HIGH_WORD] = 0;
    tpu->PARM.R[channel][TPU_PTA_LOW_WORD] = 0;

    /* configure the channel measurement mode */
    tpu_hsq(tpu, channel, mode);

    /* initialize channel */
    tpu_hsr(tpu, channel, TPU_PTA_INIT);

    /* enable channel by assigning a priority */
    tpu_enable(tpu, channel, priority);
}

/*******************************************************************************
FUNCTION      : tpu_pta_get_accumulation

PURPOSE       : This function returns the current value of the accumulation.

INPUT NOTES   : This function has 2 parameters:

                 *tpu     : This is a pointer to the TPU3 module to use. It is
                            of type TPU3_tag which is defined in m_tpu3.h
                 channel  : This is the channel number of the PTA function.

RETURN NOTES  : The current value of the 32-bit accumulation.

*******************************************************************************/
UINT32 tpu_pta_get_accumulation(struct TPU3_tag *tpu, UINT8 channel)
{
    UINT16 high;
    UINT16 low;

    high = (tpu->PARM.R[channel][TPU_PTA_HIGH_WORD]);
    low = (tpu->PARM.R[channel][TPU_PTA_LOW_WORD]);

    /* clear accumulation high word for next measurement */
    tpu->PARM.R[channel][TPU_PTA_HIGH_WORD] = 0;

    return ((UINT32) (high << 16) | low);
}

/*******************************************************************************
FUNCTION      : tpu_pta_get_period_count

PURPOSE       : This function returns the current period count.

INPUT NOTES   : This function has 2 parameters:

                 *tpu     : This is a pointer to the TPU3 module to use. It is
                            of type TPU3_tag which is defined in m_tpu3.h
                 channel  : This is the channel number of the PTA function.

RETURN NOTES  : The current period count.

*******************************************************************************/
UINT8 tpu_pta_get_period_count(struct TPU3_tag *tpu, UINT8 channel)
{
    return (UINT8) ((tpu->PARM.R[channel][TPU_PTA_MAX_CNT_PRD_CNT]) & 0x0F);
}