/*FUNCTION**********************************************************************
*
* Function Name : PIT_DRV_GetUs
* Description : Get an absolute time stamp.
* This function is useful to get elapsed time through calling this function in
* time A, and then call it in time B. The elapsed time could be get by B-A, the
* result may have 3-5 microseconds error depends on system clock frequency.
*
*END**************************************************************************/
uint32_t PIT_DRV_GetUs(void)
{
PIT_Type * base = g_pitBase[g_pitUsInstance];
/* Get current timer count, and reverse it to up-counting.*/
uint64_t currentTime = ~(((uint64_t)PIT_HAL_ReadTimerCount(base, g_pitUsChannel) << 32U) +
PIT_HAL_ReadTimerCount(base, g_pitUsChannel - 1U));
/* Convert count numbers to microseconds unit.*/
return currentTime = (currentTime * 1000U) / (g_pitSourceClock / 1000U);
}
/*FUNCTION**********************************************************************
*
* Function Name : PIT_DRV_DelayUs
* Description : Delay specific microseconds.
* The delay will have a 3-5 microseconds error depends on system clock frequency.
*
*END**************************************************************************/
void PIT_DRV_DelayUs(uint32_t us)
{
PIT_Type * base = g_pitBase[g_pitUsInstance];
uint64_t x = us * g_pitSourceClock / 1000000;
uint64_t timeToBe = ((uint64_t)PIT_HAL_ReadTimerCount(base, g_pitUsChannel) << 32U) +
PIT_HAL_ReadTimerCount(base, g_pitUsChannel - 1U) - x;
while (((uint64_t)PIT_HAL_ReadTimerCount(base, g_pitUsChannel) << 32U) +
PIT_HAL_ReadTimerCount(base, g_pitUsChannel - 1U)
>= timeToBe)
{}
}
/*!
* @cond DOXYGEN_PRIVATE
*
* @brief Atomically captures current time into HWTIMER_TIME_STRUCT structure
*
* Corrects/normalizes the values if necessary (interrupt pending, etc.)
*
* @param hwtimer[in] Pointer to hwtimer structure.
* @param time[out] Pointer to time structure. This value is filled with current value of the timer.
*
* @return kHwtimerSuccess Success.
*
* @see HWTIMER_SYS_PitInit
* @see HWTIMER_SYS_PitDeinit
* @see HWTIMER_SYS_PitSetDiv
* @see HWTIMER_SYS_PitStart
* @see HWTIMER_SYS_PitStop
* @see HWTIMER_SYS_PitIsr
* @see HWTIMER_SYS_PitIsrShared
*/
static _hwtimer_error_code_t HWTIMER_SYS_PitGetTime(hwtimer_t *hwtimer, hwtimer_time_t *time)
{
uint32_t pitChannel;
uint32_t tempCval;
uint32_t baseAddr = g_pitBaseAddr[0];
assert(NULL != hwtimer);
assert(NULL != time);
pitChannel = hwtimer->llContext[0U];
assert(pitChannel < FSL_FEATURE_PIT_TIMER_COUNT);
/* Enter critical section to avoid disabling interrupt from pit for very long time */
OSA_EnterCritical(kCriticalDisableInt);
PIT_HAL_SetIntCmd(baseAddr, pitChannel, false);
time->ticks = hwtimer->ticks;
tempCval = PIT_HAL_ReadTimerCount(baseAddr, pitChannel);
/* Check pending interrupt flag */
if (PIT_HAL_IsIntPending(baseAddr, pitChannel))
{
PIT_HAL_SetIntCmd(baseAddr, pitChannel, true);
OSA_ExitCritical(kCriticalDisableInt);
time->subTicks = hwtimer->modulo - 1U;
}
else
{
PIT_HAL_SetIntCmd(baseAddr, pitChannel, true);
OSA_ExitCritical(kCriticalDisableInt);
/* todo: following line should be updated when HAL will be updated with this functionality. */
time->subTicks = HW_PIT_LDVALn_RD(baseAddr, pitChannel) - tempCval;
}
return kHwtimerSuccess;
}
/*FUNCTION**********************************************************************
*
* Function Name : PIT_DRV_ReadTimerCount
* Description : Reads the current timer counting value.
* This function returns the real-time timer counting value, in a range from 0
* to a timer period.
*
*END**************************************************************************/
uint32_t PIT_DRV_ReadTimerCount(uint32_t instance, uint32_t channel)
{
assert(instance < PIT_INSTANCE_COUNT);
PIT_Type * base = g_pitBase[instance];
return PIT_HAL_ReadTimerCount(base, channel);
}
/*!
* @brief Function ltc_timer_stop halt pit timer
* and returns elapsed ticks.
*/
static unsigned int ltc_timer_stop(void)
{
uint32_t curr_ticks = PIT_HAL_ReadTimerCount(pitBase[0], LTC_TIMER_PIT_CHANNEL);
PIT_HAL_StopTimer(pitBase[0], LTC_TIMER_PIT_CHANNEL);
return (0xFFFFFFFFu - curr_ticks);
}
