wakeup from sleep mode with uart interrupt

[andrew_trowbridge]

Posted on October 25, 2013 at 15:00

Hi everyone

I'm trying to put my STM32L1 into sleepmode and wake it up again with an uart interrupt. So I send it to sleep using:PWR_EnterSleepMode(PWR_Regulator_ON,TRUE)which works, but now it does not wake up when I send data through the uart. Does anyone know why? Is there some flag I need to set to allow the uart isr to wake my stm up?Thanks! #stm32-uart #stm32 #interrupts

[Amel NASRI]

Posted on October 31, 2013 at 10:54

Hi Stephen,

The second parameter for ''PWR_EnterSleepMode'' should be the instruction used to enter sleep mode (PWR_SLEEPEntry_WFI or PWR_SLEEPEntry_WFE). Check this first. -Mayla-

[andrew_trowbridge]

Posted on November 17, 2013 at 15:58

Hi Mayla

Thanks for your reply! I've tried what you suggested. But the STM32 still won't wakeup. Here's my code:    RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE);    /* Select the Voltage Range 2 */    PWR_VoltageScalingConfig(PWR_VoltageScaling_Range2);    PWR_EnterSleepMode(PWR_Regulator_ON,PWR_SLEEPEntry_WFI);And this is how I configure the Uart interrupt:  GPIO_InitTypeDef GPIO_InitStructure;  EXTI_InitTypeDef EXTI_InitStructure;  NVIC_InitTypeDef NVIC_InitStructure;    RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);    /* Configure USART1 pins:  Rx ----------------------------*/  GPIO_InitStructure.GPIO_Pin =  USARTx_RX_PIN;  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_400KHz;  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;  GPIO_Init(USARTx_TX_GPIO_PORT, &GPIO_InitStructure);    /* Connect Button EXTI Line to uart rx line */  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOB,EXTI_PinSource7);    /* Configure User Button and IDD_WakeUP EXTI line */  EXTI_InitStructure.EXTI_Line = EXTI_Line7 ;  // PB7 for uart rx pin  EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;  EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;    EXTI_InitStructure.EXTI_LineCmd = ENABLE;  EXTI_Init(&EXTI_InitStructure);    /* Enable and set uart RX EXTI Interrupt to the lowest priority */  NVIC_InitStructure.NVIC_IRQChannel = EXTI9_5_IRQn ;  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x0F;  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x0F;  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;  NVIC_Init(&NVIC_InitStructure); Strange is that it does wakeup when I put it into Stop mode... Any ideas?

[hakan23]

Posted on March 26, 2014 at 07:37

Hello Stephen

Any progress on this issue ?? I want to do the same thing best regard   Håkan

[mattreed9]

Posted on May 06, 2016 at 22:26The clock for the Uart is turned off when asleep.For this to work (from what I have read) you need to run the Uart from the external low-speed clock - since that clock is not turned off when asleep.But, that clock is slow, about the fastest Uart speed you can do is 1200.-Matt