Low Power Modes For STM32L4
前言
現在MCU都會被要求有節約省電，ST針對省電版本MCU推出L系列與最新的U5系列，此章節主要會介紹各個省電模式下的操作，與Sleep mode為例子會使用到的範例程式，配合客戶目前遇到問題，提點說明要點，與注意事項。(此章節也會介紹L4系列MCU)
STM32L系列核心
這邊可以看到圖表L4的核心處理器已來到Core-M4能對應的運算效能也大大增加
Low-power modes summary
這邊會以L系列中常使用的L4為主作介紹，下表為L4在各狀態下哪些部分會進入休眠哪些是可以使用的(耗電流是可以達成的但控制條件與注意事項較為嚴苛)
Low-power modes transitions
STM32L4 Sleep mode實作
在看完上述介紹後，對於Low pow系列有比較深入認知，這邊我們來實作Low Pow Sleep mode模式
硬體注意事項
- GPIO漏電問題
- 焊接問題
GPIO漏電問題
GPIO端口在STM32進入低功耗模式後有電荷流動。这是由於有壓差所造成的，因此在進入低功耗模式前先把各GPIO腳位拉到與外界水位相同
我們可以看以下範例來協助了解
案例1:LCD模組連接MCU在進入STOP mode後功耗整板800多uA非1.6uA(代碼是相同的)
問題分析
- 摘除LCD模組後功耗下降至500uA
- 個模組都是以GPIO來控制開關
解法:GPIO在進入STOP mode前先把腳位全部拉到HIGH(LCD電為水平相同)
焊接問題
此問題其實也與GPIO問題原理雷同，主要是焊接接觸不良也會有漏電的現象
Coding撰寫
要能達到極為省電關閉部必要的Clock來源與GPIO腳位這2點是極為重要
void SystemClock_Decrease(void)
{
RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
RCC_OscInitTypeDef RCC_OscInitStruct = {0};
/* MSI is enabled in range 0 (100Khz) */
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_MSI;
RCC_OscInitStruct.MSIState = RCC_MSI_ON;
RCC_OscInitStruct.MSIClockRange = RCC_MSIRANGE_0;//100khz
RCC_OscInitStruct.MSICalibrationValue = RCC_MSICALIBRATION_DEFAULT;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
if(HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
{
/* Initialization Error */
Error_Handler();
}
/* Select MSI as system clock source and keep HCLK, PCLK1 and PCLK2 clocks dividers as before */
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_SYSCLK;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_MSI;
if(HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0) != HAL_OK)
{
/* Initialization Error */
Error_Handler();
}
/* Disable HSI to reduce power consumption since MSI is used from that point */
__HAL_RCC_HSI_DISABLE();
}
static void SystemPower_Config(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
/* Enable GPIOs clock */
__HAL_RCC_GPIOA_CLK_ENABLE();
__HAL_RCC_GPIOB_CLK_ENABLE();
__HAL_RCC_GPIOC_CLK_ENABLE();
__HAL_RCC_GPIOD_CLK_ENABLE();
__HAL_RCC_GPIOH_CLK_ENABLE();
__HAL_RCC_GPIOE_CLK_ENABLE();
__HAL_RCC_GPIOF_CLK_ENABLE();
__HAL_RCC_GPIOG_CLK_ENABLE();
/* Configure all GPIO port pins in Analog Input mode (floating input trigger OFF) */
GPIO_InitStructure.Pin = GPIO_PIN_All;
GPIO_InitStructure.Mode = GPIO_MODE_ANALOG;
GPIO_InitStructure.Pull = GPIO_NOPULL;
HAL_GPIO_Init(GPIOA, &GPIO_InitStructure);
HAL_GPIO_Init(GPIOB, &GPIO_InitStructure);
HAL_GPIO_Init(GPIOC, &GPIO_InitStructure);
HAL_GPIO_Init(GPIOD, &GPIO_InitStructure);
HAL_GPIO_Init(GPIOH, &GPIO_InitStructure);
HAL_GPIO_Init(GPIOE, &GPIO_InitStructure);
HAL_GPIO_Init(GPIOF, &GPIO_InitStructure);
HAL_GPIO_Init(GPIOG, &GPIO_InitStructure);
/* Disable GPIOs clock */
__HAL_RCC_GPIOA_CLK_DISABLE();
__HAL_RCC_GPIOB_CLK_DISABLE();
__HAL_RCC_GPIOC_CLK_DISABLE();
__HAL_RCC_GPIOD_CLK_DISABLE();
__HAL_RCC_GPIOH_CLK_DISABLE();
__HAL_RCC_GPIOE_CLK_DISABLE();
__HAL_RCC_GPIOF_CLK_DISABLE();
__HAL_RCC_GPIOG_CLK_DISABLE();
}
主程式如下
int main(void)
{
/* USER CODE BEGIN 1 */
/* USER CODE END 1 */
/* MCU Configuration--------------------------------------------------------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* USER CODE BEGIN Init */
/* USER CODE END Init */
/* Configure the system clock */
SystemClock_Config();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_USART2_UART_Init();
/* USER CODE BEGIN 2 */
BSP_LED_Init(LED2);
printf("start\n\r");
/* Disable Prefetch Buffer */
__HAL_FLASH_PREFETCH_BUFFER_DISABLE();
/* Enable Power Clock */
__HAL_RCC_PWR_CLK_ENABLE();
/* Enable Flash power down mode during Sleep mode */
/* (uncomment this line if power consumption figures */
/* must be measured with Flash still on in Low Power */
/* Sleep mode) */
__HAL_FLASH_SLEEP_POWERDOWN_ENABLE();
/* Reset all RCC Sleep and Stop modes register to */
/* improve power consumption */
RCC->AHB1SMENR = 0x0;
RCC->AHB2SMENR = 0x0;
RCC->AHB3SMENR = 0x0;
RCC->APB1SMENR1 = 0x0;
RCC->APB1SMENR2 = 0x0;
RCC->APB2SMENR = 0x0;
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
/* USER CODE END WHILE */
HAL_Delay(5000);
if (BSP_PB_GetState(BUTTON_USER) == SET)
{
SystemPower_Config();
BSP_PB_Init(BUTTON_USER, BUTTON_MODE_EXTI);
SystemClock_Decrease();
HAL_SuspendTick();
HAL_PWR_EnterSLEEPMode(PWR_LOWPOWERREGULATOR_ON, PWR_SLEEPENTRY_WFI);
HAL_PWREx_DisableLowPowerRunMode();
SystemClock_Config();
BSP_LED_Init(LED2);
HAL_ResumeTick();
}
/* USER CODE BEGIN 3 */
}
/* USER CODE END 3 */
}