/*FUNCTION**********************************************************************
*
* Function Name : PIT_DRV_InitUs
* Description : Initializes two PIT channels to serve as a microseconds unit.
* This function is in parallel with PIT_DRV_InitChannel, they will overwrite
* each other. PIT_DRV_Init must be called before calling this function.
* The microseconds unit will use two chained channels to simulate a lifetime
* timer, the channel number passed in and the "channel -1" channel will be used.
* Note:
* 1. These two channels will be occupied and could not be used with other purposes.
* 2. The channel number passed in must be greater than 0.
*END**************************************************************************/
void PIT_DRV_InitUs(uint32_t instance, uint32_t channel)
{
assert(instance < PIT_INSTANCE_COUNT);
assert(channel > 0U);
PIT_Type * base = g_pitBase[instance];
g_pitUsInstance = instance;
g_pitUsChannel = channel;
PIT_HAL_SetTimerChainCmd(base, channel, true);
PIT_HAL_SetTimerPeriodByCount(base, channel, 0xFFFFFFFFU);
PIT_HAL_SetTimerPeriodByCount(base, channel - 1U, 0xFFFFFFFFU);
PIT_HAL_StartTimer(base, channel);
PIT_HAL_StartTimer(base, channel - 1U);
}
/*!
* @cond DOXYGEN_PRIVATE
*
* @brief Sets up timer with divider settings closest to the requested period in microseconds.
*
* The function gets the value of the base frequency of the timer via clock manager and calculates required
* divider ratio.
*
* Called by hwtimer_set_freq() and hwtimer_set_period().
* Fills in the divider (actual total divider) and modulo (sub-tick resolution) members of the HWTIMER structure.
*
* @param hwtimer[in] Pointer to hwtimer structure.
* @param period[in] Required period of timer in micro seconds.
*
* @return kHwtimerSuccess Success.
*
* @see HWTIMER_SYS_PitInit
* @see HWTIMER_SYS_PitDeinit
* @see HWTIMER_SYS_PitStart
* @see HWTIMER_SYS_PitStop
* @see HWTIMER_SYS_PitGetTime
* @see HWTIMER_SYS_PitIsrAction
*/
static _hwtimer_error_code_t HWTIMER_SYS_PitSetDiv(hwtimer_t * hwtimer, uint32_t period)
{
uint32_t pitChannel;
PIT_Type * base = g_pitBase[0];
uint64_t divider;
assert(NULL != hwtimer);
/* Store clock frequency in struct. */
hwtimer->clockFreq = CLOCK_SYS_GetPitFreq(0);
divider = (((uint64_t)hwtimer->clockFreq * period)) / 1000000U ;
/* If required frequency is higher than input clock frequency, we set divider 1 (for setting the highest possible frequency) */
if (0U == divider)
{
divider = 1U;
}
/* if divider is greater than 32b value we set divider to max 32b value */
else if (divider & 0xFFFFFFFF00000000U)
{
return kHwtimerInvalidInput;
}
pitChannel = hwtimer->llContext[0U];
assert(pitChannel < FSL_FEATURE_PIT_TIMER_COUNT);
/* Set divider for pit chanell */
PIT_HAL_SetTimerPeriodByCount(base, pitChannel, divider - 1U);
hwtimer->divider = divider;
hwtimer->modulo = divider;
return kHwtimerSuccess;
}
/*FUNCTION**********************************************************************
*
* Function Name : PIT_DRV_SetTimerPeriodByCount
* Description : Sets the timer period in units of count.
* Timers begin counting from the value set by this function.
* The counter period of a running timer can be modified by first stopping
* the timer, setting a new load value, and starting the timer again. If
* timers are not restarted, the new value is loaded after the next trigger
* event.
*
*END**************************************************************************/
void PIT_DRV_SetTimerPeriodByCount(uint32_t instance, uint32_t channel, uint32_t count)
{
assert(instance < PIT_INSTANCE_COUNT);
PIT_Type * base = g_pitBase[instance];
PIT_HAL_SetTimerPeriodByCount(base, channel, count);
}
/*FUNCTION**********************************************************************
*
* Function Name : PIT_DRV_SetTimerPeriodByUs
* Description : Set timer period in microseconds unit.
* The period range depends on the frequency of PIT source clock. If required
* period is out the range, try to use lifetime timer if applicable.
* This function is only valid for one single channel. If channels are chained together,
* the period here will make no sense.
*
*END**************************************************************************/
void PIT_DRV_SetTimerPeriodByUs(uint32_t instance, uint32_t channel, uint32_t us)
{
assert(instance < PIT_INSTANCE_COUNT);
PIT_Type * base = g_pitBase[instance];
/* Calculate the count value, assign it to timer counter register.*/
uint32_t count = (uint32_t)(us * g_pitSourceClock / 1000000U - 1U);
PIT_HAL_SetTimerPeriodByCount(base, channel, count);
}
/*!
* @brief Function ltc_timer_init initialize PIT timer
* to measure time.
*/
static void ltc_timer_init(void)
{
SIM_HAL_EnableClock(SIM, kSimClockGatePit0);
PIT_HAL_Enable(pitBase[0]);
PIT_HAL_StopTimer(pitBase[0], LTC_TIMER_PIT_CHANNEL);
PIT_HAL_SetTimerPeriodByCount(pitBase[0], LTC_TIMER_PIT_CHANNEL, RELOAD);
PIT_HAL_SetIntCmd(pitBase[0], LTC_TIMER_PIT_CHANNEL, false);
PIT_HAL_SetTimerRunInDebugCmd(pitBase[0], false); /* timer stop counting in debug mode */
PIT_HAL_ClearIntFlag(pitBase[0], LTC_TIMER_PIT_CHANNEL);
}
/*FUNCTION**********************************************************************
*
* Function Name : PIT_DRV_SetLifetimeTimerPeriodByUs
* Description : Set lifetime timer period (Timers must be chained).
* Timer 1 must be chained with timer 0 before using lifetime timer. The period
* range is restricted by "period * g_pitSourceClock < max of an uint64_t integer",
* or it may cause a overflow and is not able to set correct period.
*
*END**************************************************************************/
void PIT_DRV_SetLifetimeTimerPeriodByUs(uint32_t instance, uint64_t us)
{
assert(instance < PIT_INSTANCE_COUNT);
PIT_Type * base = g_pitBase[instance];
uint64_t lifeTimeCount;
/* Calculate the counter value.*/
lifeTimeCount = us * g_pitSourceClock / 1000000U - 1U;
/* Assign to timers.*/
PIT_HAL_SetTimerPeriodByCount(base, 0U, (uint32_t)lifeTimeCount);
PIT_HAL_SetTimerPeriodByCount(base, 1U, (uint32_t)(lifeTimeCount >> 32U));
}
/*!
* @cond DOXYGEN_PRIVATE
*
* @brief Sets up timer with divider settings closest to the requested total divider factor.
*
* Called by hwtimer_set_freq() and hwtimer_set_period().
* Fills in the divider (actual total divider) and modulo (sub-tick resolution) members of the HWTIMER structure.
*
* @param hwtimer[in] Pointer to hwtimer structure.
* @param divider[in] Value which divide input clock of pit timer module to obtain requested period of timer.
*
* @return kHwtimerSuccess Success.
*
* @see HWTIMER_SYS_PitInit
* @see HWTIMER_SYS_PitDeinit
* @see HWTIMER_SYS_PitStart
* @see HWTIMER_SYS_PitStop
* @see HWTIMER_SYS_PitGetTime
* @see HWTIMER_SYS_PitIsr
* @see HWTIMER_SYS_PitIsrShared
*/
static _hwtimer_error_code_t HWTIMER_SYS_PitSetDiv(hwtimer_t * hwtimer, uint32_t divider)
{
uint32_t pitChannel;
uint32_t baseAddr = g_pitBaseAddr[0];
assert(NULL != hwtimer);
assert(0U != divider);
pitChannel = hwtimer->llContext[0U];
assert(pitChannel < FSL_FEATURE_PIT_TIMER_COUNT);
/* Set divider for pit chanell */
PIT_HAL_SetTimerPeriodByCount(baseAddr, pitChannel, divider - 1U);
hwtimer->divider = divider;
hwtimer->modulo = divider;
return kHwtimerSuccess;
}
