static void lptmr_isr(void)
{
LPTMR_ClearStatusFlags(LPTMR0, kLPTMR_TimerCompareFlag);
LPTMR_StopTimer(LPTMR0);
lp_ticker_irq_handler();
}
void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime )
{
uint32_t ulReloadValue, ulCompleteTickPeriods;
TickType_t xModifiableIdleTime;
LPTMR_Type *pxLptmrBase;
pxLptmrBase = vPortGetLptrmBase();
if (pxLptmrBase == 0) return;
/* Make sure the SysTick reload value does not overflow the counter. */
if( xExpectedIdleTime > xMaximumPossibleSuppressedTicks )
{
xExpectedIdleTime = xMaximumPossibleSuppressedTicks;
}
if (xExpectedIdleTime == 0) return;
/* Calculate the reload value required to wait xExpectedIdleTime
tick periods. -1 is used because this code will execute part way
through one of the tick periods. */
ulReloadValue = LPTMR_GetCurrentTimerCount(pxLptmrBase) + ( ulLPTimerCountsForOneTick * ( xExpectedIdleTime - 1UL ) );
/* Stop the LPTMR and systick momentarily. The time the LPTMR and systick is stopped for
is accounted for as best it can be, but using the tickless mode will
inevitably result in some tiny drift of the time maintained by the
kernel with respect to calendar time. */
LPTMR_StopTimer(pxLptmrBase);
*(portNVIC_SYSTICK_CTRL) &= ~portNVIC_SYSTICK_ENABLE_BIT;
/* Enter a critical section but don't use the taskENTER_CRITICAL()
method as that will mask interrupts that should exit sleep mode. */
__asm volatile( "cpsid i" );
/* If a context switch is pending or a task is waiting for the scheduler
to be unsuspended then abandon the low power entry. */
if( eTaskConfirmSleepModeStatus() == eAbortSleep )
{
/* Restart from whatever is left in the count register to complete
this tick period. */
*(portNVIC_SYSTICK_LOAD) = portNVIC_SYSTICK_CURRENT_VALUE_REG;
/* Restart SysTick. */
*(portNVIC_SYSTICK_CTRL) |= portNVIC_SYSTICK_ENABLE_BIT;
/* Reset the reload register to the value required for normal tick
periods. */
*(portNVIC_SYSTICK_LOAD) = ulTimerCountsForOneTick - 1UL;
/* Re-enable interrupts - see comments above __disable_interrupt()
call above. */
__asm volatile( "cpsie i" );
}