STM8S AWU low power mode

/**

  ********************************** STM8S *************** ********************

  * @file name: bsp_awu.c

  * @Author: strongerHuang

  * @Library version: V2.2.0

  * @File version: V1.0.0

  * @Date: May 10, 2017

  * @Summary: Automatic wakeup source file

  ******************************************************************************/

/*----------------------------------------------------------------------------

  ----------------------------------------------------------------------------*/

/* Included header files--------------------------------------------------------------*/

#include "AWU.h"

#include "stm8s_awu.h"

#include "stm8s_tim3.h"

/************************************************

Function name: AWU_LSIMeasurement

Function: LSI clock measurement

Parameters: None

Return value: None

Author: strongerHuang

*************************************************/

uint32_t AWU_LSIMeasurement(void)

{

  uint32_t lsi_freq_hz = 0x0;

  uint32_t fmaster = 0x0;

  uint16_t ICValue1 = 0x0;

  uint16_t ICValue2 = 0x0;

  /* Get master frequency */

  fmaster = CLK_GetClockFreq();

  /* Enable the LSI measurement: LSI clock connected to timer Input Capture 1 */

  AWU->CSR |= AWU_CSR_MSR;

#if defined (STM8S903) || defined (STM8S103) || defined (STM8S003)

  /* Measure the LSI frequency with TIMER Input Capture 1 */

  /* Capture only every 8 events!!! */

  /* Enable capture of TI1 */

TIM1_ICInit(TIM1_CHANNEL_1, TIM1_ICPOLARITY_RISING, TIM1_ICSELECTION_DIRECTTI, TIM1_ICPSC_DIV8, 0);

  /* Enable TIM1 */

  TIM1_Cmd(ENABLE);

  /* wait a capture on cc1 */

  while((TIM1->SR1 & TIM1_FLAG_CC1) != TIM1_FLAG_CC1);

  /* Get CCR1 value*/

  ICValue1 = TIM1_GetCapture1();

  TIM1_ClearFlag(TIM1_FLAG_CC1);

  /* wait a capture on cc1 */

  while((TIM1->SR1 & TIM1_FLAG_CC1) != TIM1_FLAG_CC1);

  /* Get CCR1 value*/

  ICValue2 = TIM1_GetCapture1();

  TIM1_ClearFlag(TIM1_FLAG_CC1);

  /* Disable IC1 input capture */

  TIM1->CCER1 &= (uint8_t)(~TIM1_CCER1_CC1E);

  /* Disable timer2 */

  TIM1_Cmd(DISABLE);

#else  

  /* Measure the LSI frequency with TIMER Input Capture 1 */

  /* Capture only every 8 events!!! */

  /* Enable capture of TI1 */

  TIM3_ICInit(TIM3_CHANNEL_1, TIM3_ICPOLARITY_RISING, TIM3_ICSELECTION_DIRECTTI, TIM3_ICPSC_DIV8, 0);

  /* Enable TIM3 */

  TIM3_Cmd(ENABLE);

/* wait a capture on cc1 */

  while ((TIM3->SR1 & TIM3_FLAG_CC1) != TIM3_FLAG_CC1);

/* Get CCR1 value*/

  ICValue1 = TIM3_GetCapture1();

  TIM3_ClearFlag(TIM3_FLAG_CC1);

  /* wait a capture on cc1 */

  while ((TIM3->SR1 & TIM3_FLAG_CC1) != TIM3_FLAG_CC1);

    /* Get CCR1 value*/

  ICValue2 = TIM3_GetCapture1();

TIM3_ClearFlag(TIM3_FLAG_CC1);

  /* Disable IC1 input capture */

  TIM3->CCER1 &= (uint8_t)(~TIM3_CCER1_CC1E);

  /* Disable timer3 */

  TIM3_Cmd(DISABLE);

#endif /* STM8S903 || STM8S103*/

  /* Compute LSI clock frequency */

  lsi_freq_hz = (8 * fmaster) / (ICValue2 - ICValue1);

  /* Disable the LSI measurement: LSI clock disconnected from timer Input Capture 1 */

  AWU->CSR &= (uint8_t)(~AWU_CSR_MSR);

 return (lsi_freq_hz);

}

/************************************************

Function name: AWU_Initializes

Function: AWU automatic wake-up

Parameters: None

Return value: None

Author: strongerHuang

*************************************************/

void AWU_Initializes(void)

{

  AWU_LSICalibrationConfig(AWU_LSIMeasurement()); //Calibrate LSI clock

  AWU_Init(AWU_TIMEBASE_30S); //Initialize AWU

  enableInterrupts();

}

Before entering the shutdown mode, you can turn off unnecessary power supplies, modify the microcontroller IO ports, etc.

halt(); //Enter shutdown mode

After the interrupt occurs, clear the flag: AWU_GetFlagStatus();

Can be used with a window watchdog, but not with an independent watchdog.