/**
* @brief Enters in Under-Drive STOP mode.
*
* @note This mode can be selected only when the Under-Drive is already active
*
* @note This mode is enabled only with STOP low power mode.
* In this mode, the 1.2V domain is preserved in reduced leakage mode. This
* mode is only available when the main regulator or the low power regulator
* is in low voltage mode
*
* @note If the Under-drive mode was enabled, it is automatically disabled after
* exiting Stop mode.
* When the voltage regulator operates in Under-drive mode, an additional
* startup delay is induced when waking up from Stop mode.
*
* @note In Stop mode, all I/O pins keep the same state as in Run mode.
*
* @note When exiting Stop mode by issuing an interrupt or a wakeup event,
* the HSI RC oscillator is selected as system clock.
*
* @note When the voltage regulator operates in low power mode, an additional
* startup delay is incurred when waking up from Stop mode.
* By keeping the internal regulator ON during Stop mode, the consumption
* is higher although the startup time is reduced.
*
* @param Regulator: specifies the regulator state in STOP mode.
* This parameter can be one of the following values:
* @arg PWR_MAINREGULATOR_UNDERDRIVE_ON: Main Regulator in under-drive mode
* and Flash memory in power-down when the device is in Stop under-drive mode
* @arg PWR_LOWPOWERREGULATOR_UNDERDRIVE_ON: Low Power Regulator in under-drive mode
* and Flash memory in power-down when the device is in Stop under-drive mode
* @param STOPEntry: specifies if STOP mode in entered with WFI or WFE instruction.
* This parameter can be one of the following values:
* @arg PWR_SLEEPENTRY_WFI: enter STOP mode with WFI instruction
* @arg PWR_SLEEPENTRY_WFE: enter STOP mode with WFE instruction
* @retval None
*/
HAL_StatusTypeDef HAL_PWREx_EnterUnderDriveSTOPMode(uint32_t Regulator, uint8_t STOPEntry)
{
uint32_t tempreg = 0;
uint32_t tickstart = 0;
/* Check the parameters */
assert_param(IS_PWR_REGULATOR_UNDERDRIVE(Regulator));
assert_param(IS_PWR_STOP_ENTRY(STOPEntry));
/* Enable Power ctrl clock */
__HAL_RCC_PWR_CLK_ENABLE();
/* Enable the Under-drive Mode ---------------------------------------------*/
/* Clear Under-drive flag */
__HAL_PWR_CLEAR_ODRUDR_FLAG();
/* Enable the Under-drive */
__HAL_PWR_UNDERDRIVE_ENABLE();
/* Get tick */
tickstart = HAL_GetTick();
/* Wait for UnderDrive mode is ready */
while(__HAL_PWR_GET_FLAG(PWR_FLAG_UDRDY))
{
if((HAL_GetTick() - tickstart ) > PWR_UDERDRIVE_TIMEOUT_VALUE)
{
return HAL_TIMEOUT;
}
}
/* Select the regulator state in STOP mode ---------------------------------*/
tempreg = PWR->CR1;
/* Clear PDDS, LPDS, MRLUDS and LPLUDS bits */
tempreg &= (uint32_t)~(PWR_CR1_PDDS | PWR_CR1_LPDS | PWR_CR1_LPUDS | PWR_CR1_MRUDS);
/* Set LPDS, MRLUDS and LPLUDS bits according to PWR_Regulator value */
tempreg |= Regulator;
/* Store the new value */
PWR->CR1 = tempreg;
/* Set SLEEPDEEP bit of Cortex System Control Register */
SCB->SCR |= SCB_SCR_SLEEPDEEP_Msk;
/* Select STOP mode entry --------------------------------------------------*/
if(STOPEntry == PWR_SLEEPENTRY_WFI)
{
/* Request Wait For Interrupt */
__WFI();
}
else
{
/* Request Wait For Event */
__WFE();
}
/* Reset SLEEPDEEP bit of Cortex System Control Register */
SCB->SCR &= (uint32_t)~((uint32_t)SCB_SCR_SLEEPDEEP_Msk);
return HAL_OK;
}
/**
* @brief Main program
* @param None
* @retval None
*/
int main(void)
{
/* Enable the CPU Cache */
CPU_CACHE_Enable();
/* STM32F7xx HAL library initialization:
- Configure the Flash ART accelerator on ITCM interface
- Systick timer is configured by default as source of time base, but user
can eventually implement his proper time base source (a general purpose
timer for example or other time source), keeping in mind that Time base
duration should be kept 1ms since PPP_TIMEOUT_VALUEs are defined and
handled in milliseconds basis.
- Set NVIC Group Priority to 4
- Low Level Initialization
*/
HAL_Init();
/* Configure the system clock to 216 MHz */
SystemClock_Config();
/* Since MFX is used, LED init is done after clock config */
/* Configure LED1, LED2, LED3 and LED4 */
BSP_LED_Init(LED1);
BSP_LED_Init(LED2);
BSP_LED_Init(LED3);
BSP_LED_Init(LED4);
/* Tamper push-button (EXTI15_10) will be used to wakeup the system from STOP mode */
BSP_PB_Init(BUTTON_TAMPER, BUTTON_MODE_EXTI);
/*## Configure the RTC peripheral #######################################*/
/* Enable Power Clock */
__HAL_RCC_PWR_CLK_ENABLE();
/* Allow Access to RTC Backup domaine */
HAL_PWR_EnableBkUpAccess();
RTCHandle.Instance = RTC;
/* Configure RTC prescaler and RTC data registers as follows:
- Hour Format = Format 24
- Asynch Prediv = Value according to source clock
- Synch Prediv = Value according to source clock
- OutPut = Output Disable
- OutPutPolarity = High Polarity
- OutPutType = Open Drain */
RTCHandle.Init.HourFormat = RTC_HOURFORMAT_24;
RTCHandle.Init.AsynchPrediv = RTC_ASYNCH_PREDIV;
RTCHandle.Init.SynchPrediv = RTC_SYNCH_PREDIV;
RTCHandle.Init.OutPut = RTC_OUTPUT_DISABLE;
RTCHandle.Init.OutPutPolarity = RTC_OUTPUT_POLARITY_HIGH;
RTCHandle.Init.OutPutType = RTC_OUTPUT_TYPE_OPENDRAIN;
if (HAL_RTC_Init(&RTCHandle) != HAL_OK)
{
/* Initialization Error */
Error_Handler();
}
while (1)
{
/* Turn On LED4 */
BSP_LED_On(LED4);
/* Insert 5 second delay */
HAL_Delay(5000);
/*## Configure the Wake up timer ###########################################*/
/* RTC Wakeup Interrupt Generation:
Wakeup Time Base = (RTC_WAKEUPCLOCK_RTCCLK_DIV /(LSI))
Wakeup Time = Wakeup Time Base * WakeUpCounter
= (RTC_WAKEUPCLOCK_RTCCLK_DIV /(LSI)) * WakeUpCounter
==> WakeUpCounter = Wakeup Time / Wakeup Time Base
To configure the wake up timer to 4s the WakeUpCounter is set to 0x242B:
RTC_WAKEUPCLOCK_RTCCLK_DIV = RTCCLK_Div16 = 16
Wakeup Time Base = 16 /(~37KHz) = ~0,432 ms
Wakeup Time = ~4s = 0,432ms * WakeUpCounter
==> WakeUpCounter = ~4s/0,432ms = 9259 = 0x242B */
HAL_RTCEx_SetWakeUpTimer_IT(&RTCHandle, 0x242B, RTC_WAKEUPCLOCK_RTCCLK_DIV16);
/* Turn OFF LED's */
BSP_LED_Off(LED1);
BSP_LED_Off(LED2);
BSP_LED_Off(LED4);
#ifdef UNDERDRIVE_MODE
__HAL_PWR_UNDERDRIVE_ENABLE();
#endif /* UNDERDRIVE_MODE */
/* Enter Stop Mode */
HAL_PWR_EnterSTOPMode(PWR_LOWPOWERREGULATOR_ON, PWR_STOPENTRY_WFI);
/* Disable Wakeup Counter */
HAL_RTCEx_DeactivateWakeUpTimer(&RTCHandle);
/* Configures system clock after wake-up from STOP: enable HSE, PLL and select
PLL as system clock source (HSE and PLL are disabled in STOP mode) */
SYSCLKConfig_STOP();
}
}
