void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime )
{
TickType_t wakeupTime;
/* Make sure the SysTick reload value does not overflow the counter. */
if( xExpectedIdleTime > portNRF_RTC_MAXTICKS - configEXPECTED_IDLE_TIME_BEFORE_SLEEP )
{
xExpectedIdleTime = portNRF_RTC_MAXTICKS - configEXPECTED_IDLE_TIME_BEFORE_SLEEP;
}
/* Block the scheduler now */
portDISABLE_INTERRUPTS();
/* Stop tick events */
nrf_rtc_int_disable(portNRF_RTC_REG, NRF_RTC_INT_TICK_MASK);
/* Configure CTC interrupt */
wakeupTime = nrf_rtc_counter_get(portNRF_RTC_REG) + xExpectedIdleTime;
wakeupTime &= portNRF_RTC_MAXTICKS;
nrf_rtc_cc_set(portNRF_RTC_REG, 0, wakeupTime);
nrf_rtc_event_clear(portNRF_RTC_REG, NRF_RTC_EVENT_COMPARE_0);
nrf_rtc_int_enable(portNRF_RTC_REG, NRF_RTC_INT_COMPARE0_MASK);
if( eTaskConfirmSleepModeStatus() == eAbortSleep )
{
portENABLE_INTERRUPTS();
}
else
{
TickType_t xModifiableIdleTime = xExpectedIdleTime;
configPRE_SLEEP_PROCESSING( xModifiableIdleTime );
if( xModifiableIdleTime > 0 )
{
__DSB();
do{
__WFE();
} while(0 == (NVIC->ISPR[0]));
}
configPOST_SLEEP_PROCESSING( xExpectedIdleTime );
portENABLE_INTERRUPTS();
}
// We can do operations below safely, because when we are inside vPortSuppressTicksAndSleep
// scheduler is already suspended.
nrf_rtc_int_disable(portNRF_RTC_REG, NRF_RTC_INT_COMPARE0_MASK);
nrf_rtc_int_enable (portNRF_RTC_REG, NRF_RTC_INT_TICK_MASK);
}
__weak void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime )
{
uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements, ulSysTickCTRL;
TickType_t xModifiableIdleTime;
/* Make sure the SysTick reload value does not overflow the counter. */
if( xExpectedIdleTime > xMaximumPossibleSuppressedTicks )
{
xExpectedIdleTime = xMaximumPossibleSuppressedTicks;
}
/* Stop the SysTick momentarily. The time the 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. */
portNVIC_SYSTICK_CTRL_REG &= ~portNVIC_SYSTICK_ENABLE_BIT;
/* 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 = portNVIC_SYSTICK_CURRENT_VALUE_REG + ( ulTimerCountsForOneTick * ( xExpectedIdleTime - 1UL ) );
if( ulReloadValue > ulStoppedTimerCompensation )
{
ulReloadValue -= ulStoppedTimerCompensation;
}
/* Enter a critical section but don't use the taskENTER_CRITICAL()
method as that will mask interrupts that should exit sleep mode. */
__disable_irq();
/* 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_REG = portNVIC_SYSTICK_CURRENT_VALUE_REG;
/* Restart SysTick. */
portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT;
/* Reset the reload register to the value required for normal tick
periods. */
portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL;
/* Re-enable interrupts - see comments above __disable_irq() call
above. */
__enable_irq();
}
else
{
/* Set the new reload value. */
portNVIC_SYSTICK_LOAD_REG = ulReloadValue;
/* Clear the SysTick count flag and set the count value back to
zero. */
portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;
/* Restart SysTick. */
portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT;
/* Sleep until something happens. configPRE_SLEEP_PROCESSING() can
set its parameter to 0 to indicate that its implementation contains
its own wait for interrupt or wait for event instruction, and so wfi
should not be executed again. However, the original expected idle
time variable must remain unmodified, so a copy is taken. */
xModifiableIdleTime = xExpectedIdleTime;
configPRE_SLEEP_PROCESSING( xModifiableIdleTime );
if( xModifiableIdleTime > 0 )
{
__dsb( portSY_FULL_READ_WRITE );
__wfi();
__isb( portSY_FULL_READ_WRITE );
}
configPOST_SLEEP_PROCESSING( xExpectedIdleTime );
/* Stop SysTick. Again, the time the 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. */
ulSysTickCTRL = portNVIC_SYSTICK_CTRL_REG;
portNVIC_SYSTICK_CTRL_REG = ( ulSysTickCTRL & ~portNVIC_SYSTICK_ENABLE_BIT );
/* Re-enable interrupts - see comments above __disable_irq() call
above. */
__enable_irq();
if( ( ulSysTickCTRL & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 )
{
uint32_t ulCalculatedLoadValue;
/* The tick interrupt has already executed, and the SysTick
count reloaded with ulReloadValue. Reset the
portNVIC_SYSTICK_LOAD_REG with whatever remains of this tick
period. */
ulCalculatedLoadValue = ( ulTimerCountsForOneTick - 1UL ) - ( ulReloadValue - portNVIC_SYSTICK_CURRENT_VALUE_REG );
/* Don't allow a tiny value, or values that have somehow
underflowed because the post sleep hook did something
that took too long. */
if( ( ulCalculatedLoadValue < ulStoppedTimerCompensation ) || ( ulCalculatedLoadValue > ulTimerCountsForOneTick ) )
{
ulCalculatedLoadValue = ( ulTimerCountsForOneTick - 1UL );
}
portNVIC_SYSTICK_LOAD_REG = ulCalculatedLoadValue;
/* The tick interrupt handler will already have pended the tick
processing in the kernel. As the pending tick will be
processed as soon as this function exits, the tick value
maintained by the tick is stepped forward by one less than the
time spent waiting. */
ulCompleteTickPeriods = xExpectedIdleTime - 1UL;
}
else
{
/* Something other than the tick interrupt ended the sleep.
Work out how long the sleep lasted rounded to complete tick
periods (not the ulReload value which accounted for part
ticks). */
ulCompletedSysTickDecrements = ( xExpectedIdleTime * ulTimerCountsForOneTick ) - portNVIC_SYSTICK_CURRENT_VALUE_REG;
/* How many complete tick periods passed while the processor
was waiting? */
ulCompleteTickPeriods = ulCompletedSysTickDecrements / ulTimerCountsForOneTick;
/* The reload value is set to whatever fraction of a single tick
period remains. */
portNVIC_SYSTICK_LOAD_REG = ( ( ulCompleteTickPeriods + 1 ) * ulTimerCountsForOneTick ) - ulCompletedSysTickDecrements;
}
/* Restart SysTick so it runs from portNVIC_SYSTICK_LOAD_REG
again, then set portNVIC_SYSTICK_LOAD_REG back to its standard
value. The critical section is used to ensure the tick interrupt
can only execute once in the case that the reload register is near
zero. */
portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;
portENTER_CRITICAL();
{
portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT;
vTaskStepTick( ulCompleteTickPeriods );
portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL;
}
portEXIT_CRITICAL();
}
}
__attribute__((weak)) void vPortSuppressTicksAndSleep( portTickType xExpectedIdleTime )
{
unsigned long ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickIncrements;
/* Make sure the SysTick reload value does not overflow the counter. */
if( xExpectedIdleTime > xMaximumPossibleSuppressedTicks )
{
xExpectedIdleTime = xMaximumPossibleSuppressedTicks;
}
/* 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, and the fraction of a tick period is
accounted for later. */
ulReloadValue = ( ulTimerReloadValueForOneTick * ( xExpectedIdleTime - 1UL ) );
if( ulReloadValue > ulStoppedTimerCompensation )
{
ulReloadValue -= ulStoppedTimerCompensation;
}
/* Stop the SysTick momentarily. The time the 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. */
portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT;
/* If a context switch is pending then abandon the low power entry as
the context switch might have been pended by an external interrupt that
requires processing. */
if( ( portNVIC_INT_CTRL_REG & portNVIC_PENDSVSET_BIT ) != 0 )
{
/* Restart SysTick. */
portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT;
}
else
{
/* Adjust the reload value to take into account that the current
time slice is already partially complete. */
ulReloadValue += ( portNVIC_SYSTICK_LOAD_REG - ( portNVIC_SYSTICK_LOAD_REG - portNVIC_SYSTICK_CURRENT_VALUE_REG ) );
portNVIC_SYSTICK_LOAD_REG = ulReloadValue;
/* Clear the SysTick count flag and set the count value back to
zero. */
portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;
/* Restart SysTick. */
portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT;
/* Sleep until something happens. */
configPRE_SLEEP_PROCESSING( xExpectedIdleTime );
if( xExpectedIdleTime > 0 )
{
__asm volatile( "wfi" );
}
configPOST_SLEEP_PROCESSING( xExpectedIdleTime );
/* Stop SysTick. Again, the time the 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. */
portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT;
if( ( portNVIC_SYSTICK_CTRL_REG & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 )
{
/* The tick interrupt has already executed, and the SysTick
count reloaded with the portNVIC_SYSTICK_LOAD_REG value.
Reset the portNVIC_SYSTICK_LOAD_REG with whatever remains of
this tick period. */
portNVIC_SYSTICK_LOAD_REG = ulTimerReloadValueForOneTick - ( ulReloadValue - portNVIC_SYSTICK_CURRENT_VALUE_REG );
/* The tick interrupt handler will already have pended the tick
processing in the kernel. As the pending tick will be
processed as soon as this function exits, the tick value
maintained by the tick is stepped forward by one less than the
time spent waiting. */
ulCompleteTickPeriods = xExpectedIdleTime - 1UL;
}
else
{
/* Something other than the tick interrupt ended the sleep.
Work out how long the sleep lasted. */
ulCompletedSysTickIncrements = ( xExpectedIdleTime * ulTimerReloadValueForOneTick ) - portNVIC_SYSTICK_CURRENT_VALUE_REG;
/* How many complete tick periods passed while the processor
was waiting? */
ulCompleteTickPeriods = ulCompletedSysTickIncrements / ulTimerReloadValueForOneTick;
/* The reload value is set to whatever fraction of a single tick
period remains. */
portNVIC_SYSTICK_LOAD_REG = ( ( ulCompleteTickPeriods + 1 ) * ulTimerReloadValueForOneTick ) - ulCompletedSysTickIncrements;
}
/* Restart SysTick so it runs from portNVIC_SYSTICK_LOAD_REG
again, then set portNVIC_SYSTICK_LOAD_REG back to its standard
value. */
portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;
portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT;
vTaskStepTick( ulCompleteTickPeriods );
}
/**************************************************************************//**
* @brief vPortSetupTimerInterrupt
* Override the default definition of vPortSuppressTicksAndSleep() that is weakly
* defined in the FreeRTOS Cortex-M3 port layer layer
*****************************************************************************/
void vPortSuppressTicksAndSleep(portTickType xExpectedIdleTime)
{
unsigned long ulReloadValue, ulCompleteTickPeriods;
portTickType xModifiableIdleTime;
/* Make sure the SysTick reload value does not overflow the counter. */
if (xExpectedIdleTime > xMaximumPossibleSuppressedTicks)
{
xExpectedIdleTime = xMaximumPossibleSuppressedTicks;
}
/* 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, and the fraction of a tick period is
* accounted for later. */
ulReloadValue = (ulTimerReloadValueForOneTick * (xExpectedIdleTime ));
if (ulReloadValue > ulStoppedTimerCompensation)
{
ulReloadValue -= ulStoppedTimerCompensation;
}
/* Stop the SysTick momentarily. The time the 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. */
/* Stop the RTC clock*/
BURTC_Enable(false);
/* Enter a critical section but don't use the taskENTER_CRITICAL()
* method as that will mask interrupts that should exit sleep mode. */
INT_Disable();
/* The tick flag is set to false before sleeping. If it is true when sleep
* mode is exited then sleep mode was probably exited because the tick was
* suppressed for the entire xExpectedIdleTime period. */
intTickFlag = false;
/* 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)
{
BURTC_Enable(true);
/* Re-enable interrupts */
INT_Enable();
}
else
{
/* Set the new reload value. */
ulReloadValue -= BURTC_CounterGet();
BURTC_CompareSet(0, ulReloadValue);
/* Restart the counter*/
BURTC_CounterReset();
/* Sleep until something happens. configPRE_SLEEP_PROCESSING() can
* set its parameter to 0 to indicate that its implementation contains
* its own wait for interrupt or wait for event instruction, and so wfi
* should not be executed again. However, the original expected idle
* time variable must remain unmodified, so a copy is taken. */
xModifiableIdleTime = xExpectedIdleTime;
configPRE_SLEEP_PROCESSING(xModifiableIdleTime);
if (xModifiableIdleTime > 0)
{
SLEEP_Sleep();
__DSB();
__ISB();
}
configPOST_SLEEP_PROCESSING(xExpectedIdleTime);
/* Stop SysTick. Again, the time the 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. */
BURTC_Enable(false);
/* Re-enable interrupts - see comments above __disable_interrupt()
* call above. */
INT_Enable();
if (intTickFlag != false)
{
/* The tick interrupt has already executed,
* Reset the alarm value with whatever remains of this tick period. */
BURTC_CompareSet(0, TIMER_CAPACITY & (ulTimerReloadValueForOneTick - BURTC_CounterGet()));
/* The tick interrupt handler will already have pended the tick
* processing in the kernel. As the pending tick will be
* processed as soon as this function exits, the tick value
* maintained by the tick is stepped forward by one less than the
* time spent waiting. */
ulCompleteTickPeriods = xExpectedIdleTime - 1UL;
}
else
{
/* Some other interrupt than system tick ended the sleep.
* Calculate how many tick periods passed while the processor
* was waiting */
ulCompleteTickPeriods = BURTC_CounterGet() / ulTimerReloadValueForOneTick;
/* The reload value is set to whatever fraction of a single tick
* period remains. */
if (ulCompleteTickPeriods == 0)
{
ulReloadValue = ulTimerReloadValueForOneTick - BURTC_CounterGet();
}
else
{
ulReloadValue = BURTC_CounterGet() - (ulCompleteTickPeriods * ulTimerReloadValueForOneTick);
}
BURTC_CompareSet(0, ulReloadValue);
}
/* Restart the RTCounter*/
BURTC_CounterReset();
/* The tick forward by the number of tick periods that
* remained in a low power state. */
vTaskStepTick(ulCompleteTickPeriods);
}
}
void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime )
{
uint32_t ulReloadValue, ulCompleteTickPeriods, ulCountAfterSleep;
eSleepModeStatus eSleepAction;
TickType_t xModifiableIdleTime;
/* THIS FUNCTION IS CALLED WITH THE SCHEDULER SUSPENDED. */
/* Make sure the RTC reload value does not overflow the counter. */
if( xExpectedIdleTime > xMaximumPossibleSuppressedTicks )
{
xExpectedIdleTime = xMaximumPossibleSuppressedTicks;
}
/* Calculate the reload value required to wait xExpectedIdleTime tick
periods. */
ulReloadValue = ulReloadValueForOneTick * xExpectedIdleTime;
if( ulReloadValue > ulStoppedTimerCompensation )
{
/* Compensate for the fact that the RTC is going to be stopped
momentarily. */
ulReloadValue -= ulStoppedTimerCompensation;
}
/* Stop the RTC momentarily. The time the RTC 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. */
RTCC_Enable( false );
/* Enter a critical section but don't use the taskENTER_CRITICAL() method as
that will mask interrupts that should exit sleep mode. */
INT_Disable();
__asm volatile( "dsb" );
__asm volatile( "isb" );
/* The tick flag is set to false before sleeping. If it is true when sleep
mode is exited then sleep mode was probably exited because the tick was
suppressed for the entire xExpectedIdleTime period. */
ulTickFlag = pdFALSE;
/* If a context switch is pending then abandon the low power entry as the
context switch might have been pended by an external interrupt that requires
processing. */
eSleepAction = eTaskConfirmSleepModeStatus();
if( eSleepAction == eAbortSleep )
{
/* Restart tick and continue counting to complete the current time
slice. */
RTCC_Enable( true );
/* Re-enable interrupts - see comments above the RTCC_Enable() call
above. */
INT_Enable();
}
else
{
RTCC_ChannelCCVSet( lpRTCC_CHANNEL, ulReloadValue );
/* Restart the RTC. */
RTCC_Enable( true );
/* Allow the application to define some pre-sleep processing. */
xModifiableIdleTime = xExpectedIdleTime;
configPRE_SLEEP_PROCESSING( xModifiableIdleTime );
/* xExpectedIdleTime being set to 0 by configPRE_SLEEP_PROCESSING()
means the application defined code has already executed the WAIT
instruction. */
if( xModifiableIdleTime > 0 )
{
__asm volatile( "dsb" );
SLEEP_Sleep();
__asm volatile( "isb" );
}
/* Allow the application to define some post sleep processing. */
configPOST_SLEEP_PROCESSING( xModifiableIdleTime );
/* Stop RTC. Again, the time the 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. */
RTCC_Enable( false );
ulCountAfterSleep = RTCC_CounterGet();
/* Re-enable interrupts - see comments above the INT_Enable() call
above. */
INT_Enable();
__asm volatile( "dsb" );
__asm volatile( "isb" );
if( ulTickFlag != pdFALSE )
{
/* The tick interrupt has already executed, although because this
function is called with the scheduler suspended the actual tick
processing will not occur until after this function has exited.
The tick interrupt handler will already have pended the tick
processing in the kernel. As the pending tick will be processed as
soon as this function exits, the tick value maintained by the tick
is stepped forward by one less than the time spent sleeping. The
actual stepping of the tick appears later in this function. */
ulCompleteTickPeriods = xExpectedIdleTime - 1UL;
/* The interrupt should have reset the CCV value. */
configASSERT( RTCC_ChannelCCVGet( lpRTCC_CHANNEL ) == ulReloadValueForOneTick );
}
else
{
/* Something other than the tick interrupt ended the sleep. How
many complete tick periods passed while the processor was
sleeping? */
ulCompleteTickPeriods = ulCountAfterSleep / ulReloadValueForOneTick;
/* The next interrupt is configured to occur at whatever fraction of
the current tick period remains by setting the reload value back to
that required for one tick, and truncating the count to remove the
counts that are greater than the reload value. */
RTCC_ChannelCCVSet( lpRTCC_CHANNEL, ulReloadValueForOneTick );
ulCountAfterSleep %= ulReloadValueForOneTick;
RTCC_CounterSet( ulCountAfterSleep );
}
/* Restart the RTC so it runs up to the alarm value. The alarm value
will get set to the value required to generate exactly one tick period
the next time the RTC interrupt executes. */
RTCC_Enable( true );
/* Wind the tick forward by the number of tick periods that the CPU
remained in a low power state. */
vTaskStepTick( ulCompleteTickPeriods );
}
/* Override the default definition of vPortSuppressTicksAndSleep() that is weakly
defined in the FreeRTOS Cortex-M3 port layer with a version that manages the
asynchronous timer (AST), as the tick is generated from the low power AST and
not the SysTick as would normally be the case on a Cortex-M. */
void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime )
{
uint32_t ulAlarmValue, ulCompleteTickPeriods, ulInterruptStatus;
eSleepModeStatus eSleepAction;
TickType_t xModifiableIdleTime;
enum sleepmgr_mode xSleepMode;
/* THIS FUNCTION IS CALLED WITH THE SCHEDULER SUSPENDED. */
/* Make sure the AST reload value does not overflow the counter. */
if( xExpectedIdleTime > xMaximumPossibleSuppressedTicks )
{
xExpectedIdleTime = xMaximumPossibleSuppressedTicks;
}
/* Calculate the reload value required to wait xExpectedIdleTime tick
periods. */
ulAlarmValue = ulAlarmValueForOneTick * xExpectedIdleTime;
if( ulAlarmValue > ulStoppedTimerCompensation )
{
/* Compensate for the fact that the AST is going to be stopped
momentarily. */
ulAlarmValue -= ulStoppedTimerCompensation;
}
/* Stop the AST momentarily. The time the AST 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. */
prvDisableAST();
/* Enter a critical section but don't use the taskENTER_CRITICAL() method as
that will mask interrupts that should exit sleep mode. */
ulInterruptStatus = cpu_irq_save();
/* The tick flag is set to false before sleeping. If it is true when sleep
mode is exited then sleep mode was probably exited because the tick was
suppressed for the entire xExpectedIdleTime period. */
ulTickFlag = pdFALSE;
/* If a context switch is pending then abandon the low power entry as
the context switch might have been pended by an external interrupt that
requires processing. */
eSleepAction = eTaskConfirmSleepModeStatus();
if( eSleepAction == eAbortSleep )
{
/* Restart tick. */
prvEnableAST();
/* Re-enable interrupts - see comments above the cpsid instruction()
above. */
cpu_irq_restore( ulInterruptStatus );
}
else
{
/* Adjust the alarm value to take into account that the current time
slice is already partially complete. */
ulAlarmValue -= ast_read_counter_value( AST );
ast_write_alarm0_value( AST, ulAlarmValue );
/* Restart the AST. */
prvEnableAST();
/* Allow the application to define some pre-sleep processing. */
xModifiableIdleTime = xExpectedIdleTime;
configPRE_SLEEP_PROCESSING( xModifiableIdleTime );
/* xExpectedIdleTime being set to 0 by configPRE_SLEEP_PROCESSING()
means the application defined code has already executed the WAIT
instruction. */
if( xModifiableIdleTime > 0 )
{
/* Find the deepest allowable sleep mode. */
xSleepMode = sleepmgr_get_sleep_mode();
if( xSleepMode != SLEEPMGR_ACTIVE )
{
/* Sleep until something happens. */
bpm_sleep( BPM, xSleepMode );
}
}
/* Allow the application to define some post sleep processing. */
configPOST_SLEEP_PROCESSING( xModifiableIdleTime );
/* Stop AST. Again, the time the 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. */
prvDisableAST();
/* Re-enable interrupts - see comments above the cpsid instruction()
above. */
cpu_irq_restore( ulInterruptStatus );
if( ulTickFlag != pdFALSE )
{
/* The tick interrupt has already executed, although because this
function is called with the scheduler suspended the actual tick
processing will not occur until after this function has exited.
Reset the alarm value with whatever remains of this tick period. */
ulAlarmValue = ulAlarmValueForOneTick - ast_read_counter_value( AST );
ast_write_alarm0_value( AST, ulAlarmValue );
/* The tick interrupt handler will already have pended the tick
processing in the kernel. As the pending tick will be processed as
soon as this function exits, the tick value maintained by the tick
is stepped forward by one less than the time spent sleeping. The
actual stepping of the tick appears later in this function. */
ulCompleteTickPeriods = xExpectedIdleTime - 1UL;
}
else
{
/* Something other than the tick interrupt ended the sleep. How
many complete tick periods passed while the processor was
sleeping? */
ulCompleteTickPeriods = ast_read_counter_value( AST ) / ulAlarmValueForOneTick;
/* The alarm value is set to whatever fraction of a single tick
period remains. */
ulAlarmValue = ast_read_counter_value( AST ) - ( ulCompleteTickPeriods * ulAlarmValueForOneTick );
if( ulAlarmValue == 0 )
{
/* There is no fraction remaining. */
ulAlarmValue = ulAlarmValueForOneTick;
ulCompleteTickPeriods++;
}
ast_write_counter_value( AST, 0 );
ast_write_alarm0_value( AST, ulAlarmValue );
}
/* Restart the AST so it runs up to the alarm value. The alarm value
will get set to the value required to generate exactly one tick period
the next time the AST interrupt executes. */
prvEnableAST();
/* Wind the tick forward by the number of tick periods that the CPU
remained in a low power state. */
vTaskStepTick( ulCompleteTickPeriods );
}
}
void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime )
{
/*
* Implementation note:
*
* To help debugging the option configUSE_TICKLESS_IDLE_SIMPLE_DEBUG was presented.
* This option would make sure that even if program execution was stopped inside
* this function no more than expected number of ticks would be skipped.
*
* Normally RTC works all the time even if firmware execution was stopped
* and that may lead to skipping too much of ticks.
*/
TickType_t enterTime;
/* Make sure the SysTick reload value does not overflow the counter. */
if ( xExpectedIdleTime > portNRF_RTC_MAXTICKS - configEXPECTED_IDLE_TIME_BEFORE_SLEEP )
{
xExpectedIdleTime = portNRF_RTC_MAXTICKS - configEXPECTED_IDLE_TIME_BEFORE_SLEEP;
}
/* Block the scheduler now */
portDISABLE_INTERRUPTS();
/* Configure CTC interrupt */
enterTime = nrf_rtc_counter_get(portNRF_RTC_REG);
if ( eTaskConfirmSleepModeStatus() == eAbortSleep )
{
portENABLE_INTERRUPTS();
}
else
{
TickType_t xModifiableIdleTime;
TickType_t wakeupTime = (enterTime + xExpectedIdleTime) & portNRF_RTC_MAXTICKS;
/* Stop tick events */
nrf_rtc_int_disable(portNRF_RTC_REG, NRF_RTC_INT_TICK_MASK);
/* Configure CTC interrupt */
nrf_rtc_cc_set(portNRF_RTC_REG, 0, wakeupTime);
nrf_rtc_event_clear(portNRF_RTC_REG, NRF_RTC_EVENT_COMPARE_0);
nrf_rtc_int_enable(portNRF_RTC_REG, NRF_RTC_INT_COMPARE0_MASK);
__DSB();
/* Sleep until something happens. configPRE_SLEEP_PROCESSING() can
* set its parameter to 0 to indicate that its implementation contains
* its own wait for interrupt or wait for event instruction, and so wfi
* should not be executed again. However, the original expected idle
* time variable must remain unmodified, so a copy is taken. */
xModifiableIdleTime = xExpectedIdleTime;
configPRE_SLEEP_PROCESSING( xModifiableIdleTime );
if ( xModifiableIdleTime > 0 )
{
#ifdef SOFTDEVICE_PRESENT
sd_app_evt_wait();
#else
do{
__WFE();
} while (0 == (NVIC->ISPR[0]));
#endif
}
configPOST_SLEEP_PROCESSING( xExpectedIdleTime );
nrf_rtc_int_disable(portNRF_RTC_REG, NRF_RTC_INT_COMPARE0_MASK);
portENABLE_INTERRUPTS();
/* Correct the system ticks */
portENTER_CRITICAL();
{
TickType_t diff;
TickType_t hwTicks = nrf_rtc_counter_get(portNRF_RTC_REG);
nrf_rtc_event_clear(portNRF_RTC_REG, NRF_RTC_EVENT_TICK);
nrf_rtc_int_enable (portNRF_RTC_REG, NRF_RTC_INT_TICK_MASK);
if(enterTime > hwTicks)
{
hwTicks += portNRF_RTC_MAXTICKS + 1U;
}
diff = (hwTicks - enterTime);
if((configUSE_TICKLESS_IDLE_SIMPLE_DEBUG) && (diff > xExpectedIdleTime))
{
diff = xExpectedIdleTime;
}
if (diff > 0)
{
vTaskStepTick(diff);
}
}
portEXIT_CRITICAL();
}
}