详细内容见参考手册—Power control (PWR)
在STM32应用中,为了降低功耗共有以下三种工作模式:
备注:
The RTC, the IWDG, and the corresponding clock sources are not stopped by entering Stop or Standby mode.
另外,在正常工作模式(Run mode)下,可以通过以下方法有效降低功耗:
降低系统时钟(system clocks)
关闭不需要的APB和AHB外设时钟
STM32F0-参考手册–>6 Power control (PWR)
RM0360 Reference manual STM32F030x4/x6/x8/xC and STM32F070x6/xB
STM32F0-数据手册–>3.5 Power management
DS9773 STM32F030x4 STM32F030x6 STM32F030x8
STM32F0-编程手册–>2.5 Power management
PM0215 STM32F0xxx单片机编程手册
STM32F0-应用笔记
如何使用USART或LPUART从低功耗模式唤醒STM32F0 / F3 / L0 / L4微控制器
应用平台:STM32F030
main.c
#include "stm32f0xx.h"
/* Private variables ---------------------------------------------------------*/
uint8_t DataReceived = 0;
extern __IO uint8_t InterruptCounter;
/* Private function prototypes -----------------------------------------------*/
static void USART_Config(void);
static void WakeUp_StartBitMethod(void);
static void RestoreConfiguration(void);
/**
* @brief Main program
* @param None
* @retval None
*/
int main(void)
{
/* Initialize LEDs available ***********************************************/
STM_EVAL_LEDInit(LED);
/* USART configuration */
USART_Config();
/* Wake up from USART STOP mode by Start bit Method */
WakeUp_StartBitMethod();
/* Configure SystemClock*/
RestoreConfiguration();
/* Configure and enable the systick timer to generate an interrupt each 1 ms */
SysTick_Config((SystemCoreClock / 1000));
while (1)
{}
}
/**
* @brief Start Bit Method to Wake Up USART from Stop mode Test.
* @param None
* @retval None
*/
static void WakeUp_StartBitMethod(void)
{
/* Configure the wake up Method = Start bit */
USART_StopModeWakeUpSourceConfig(USART1, USART_WakeUpSource_StartBit);
/* Enable USART1 */
USART_Cmd(USART1, ENABLE);
/* Before entering the USART in STOP mode the REACK flag must be checked to ensure the USART RX is ready */
while(USART_GetFlagStatus(USART1, USART_FLAG_REACK) == RESET)
{}
/* Enable USART STOP mode by setting the UESM bit in the CR1 register.*/
USART_STOPModeCmd(USART1, ENABLE);
/* Enable the wake up from stop Interrupt */
USART_ITConfig(USART1, USART_IT_WU, ENABLE);
/* Enable PWR APB clock */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE);
/* Enter USART in STOP mode with regulator in low power mode */
PWR_EnterSTOPMode(PWR_Regulator_LowPower, PWR_STOPEntry_WFI);
/* Waiting Wake Up interrupt */
while(InterruptCounter == 0x00)
{}
/* Disable USART peripheral in STOP mode */
USART_STOPModeCmd(USART1, DISABLE);
while(USART_GetFlagStatus(USART1, USART_FLAG_RXNE) == RESET)
{}
DataReceived = USART_ReceiveData(USART1);
/* Clear the TE bit (if a transmission is on going or a data is in the TDR, it will be sent before efectivelly disabling the transmission) */
USART_DirectionModeCmd(USART1, USART_Mode_Tx, DISABLE);
/* Check the Transfer Complete Flag */
while (USART_GetFlagStatus(USART1, USART_FLAG_TC) == RESET)
{}
/* USART Disable */
USART_Cmd(USART1, DISABLE);
}
/**
* @brief Configure the USART Device
* @param None
* @retval None
*/
static void USART_Config(void)
{
USART_InitTypeDef USART_InitStructure;
GPIO_InitTypeDef GPIO_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
/* Enable GPIO&USART clock */
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA , ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);
/* Configure the HSI as USART clock */
RCC_USARTCLKConfig(RCC_USART2CLK_HSI);
/* USARTx Pins configuration **************************************************/
/* Connect pin to Periph */
GPIO_PinAFConfig(GPIOA, GPIO_PinSource9, GPIO_AF_1);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource10, GPIO_AF_1);
/* Configure pins as AF pushpull */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9 | GPIO_Pin_10;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOA, &GPIO_InitStructure);
/* USARTx configured as follow:
- BaudRate = 115200 baud
- Word Length = 8 Bits
- Stop Bit = 1 Stop Bit
- Parity = No Parity
- Hardware flow control disabled (RTS and CTS signals)
- Receive and transmit enabled
*/
USART_DeInit(USART1);
USART_InitStructure.USART_BaudRate = 115200;
USART_InitStructure.USART_WordLength = USART_WordLength_8b;
USART_InitStructure.USART_StopBits = USART_StopBits_1;
USART_InitStructure.USART_Parity = USART_Parity_No;
USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
USART_Init(USART1, &USART_InitStructure);
/* USART2 IRQ Channel configuration */
NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPriority = 0x01;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}
/**
* @brief Restore peripheral config before entering STOP mode.
* @param None
* @retval None
*/
static void RestoreConfiguration(void)
{
__IO uint32_t StartUpCounter = 0, HSEStatus = 0;
/* SYSCLK, HCLK, PCLK configuration ----------------------------------------*/
/* Enable HSE */
RCC_HSEConfig(RCC_HSE_ON);
/* Wait till HSE is ready and if Time out is reached exit */
HSEStatus = RCC_WaitForHSEStartUp();
if (HSEStatus == (uint32_t)0x01)
{
/* Enable Prefetch Buffer */
FLASH_SetLatency(FLASH_Latency_1);
/* HCLK = SYSCLK */
RCC_HCLKConfig(RCC_SYSCLK_Div1);
/* PCLK = HCLK */
RCC_PCLKConfig(RCC_HCLK_Div1);
/* PLL configuration: = HSE * 6 = 48 MHz */
RCC_PREDIV1Config(RCC_PREDIV1_Div1);
RCC_PLLConfig(RCC_PLLSource_PREDIV1, RCC_CFGR_PLLMULL6);
/* Enable PLL */
RCC_PLLCmd(ENABLE);
/* PLL as system clock source */
RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);
}
}
stm32f0xx_it.c
/* Includes ------------------------------------------------------------------*/
#include "stm32f0xx_it.h"
/* Private variables ---------------------------------------------------------*/
__IO uint8_t InterruptCounter = 0x00;
__IO uint8_t Counter = 0;
/**
* @brief This function handles SysTick Handler.
* @param None
* @retval None
*/
void SysTick_Handler(void)
{
if (Counter == 20)
{
/* Toggle LED's */
STM_EVAL_LEDToggle(LED);
/* Reset Counter */
Counter = 0;
}
else
{
/* increment Counter */
Counter++;
}
}
/**
* @brief This function handles USART interrupt request.
* @param None
* @retval None
*/
void USART1_IRQHandler(void)
{
if (USART_GetITStatus(USART1, USART_IT_WU) == SET)
{
/* Clear The USART WU flag */
USART_ClearITPendingBit(USART1, USART_IT_WU);
InterruptCounter = 0x01;
}
}
然而,在STM32F030中不能配置为USART的start位唤醒。
#define USART_IT_WU ((uint32_t)0x00140316) /*!< Not available for STM32F030 devices */