Question
STM32L4 STOP2 mode current jumps from 1 µA to 50 µA when enabling GPIO wake-up
Hi,
I’m working on an STM32L431CBT6 project where I enter STOP2 mode and measure ~1 µA current, which is great. However, I need to use PA0 as a GPIO input to wake up the MCU from STOP2.
When I configure PA0 as an input (no pull, or pull-up/down), my STOP2 current jumps to about 50 µA.
Here’s the relevant setup:
MCU: STM32L431CBT6
Toolchain: CubeMX + HAL
STOP2 entry via HAL_PWREx_EnterSTOP2Mode(PWR_STOPENTRY_WFI)
All unused GPIOs are set to analog mode
PA0 configured as GPIO_MODE_INPUT
Supply voltage: 3.3V
Current measured with multimeter
void Enter_Stop2_Mode(void)
{
// Set all GPIOs to analog
GPIO_InitTypeDef gpio = {0};
gpio.Mode = GPIO_MODE_ANALOG;
gpio.Pull = GPIO_NOPULL;
gpio.Pin = GPIO_PIN_All;
// Set all pins to analog mode
HAL_GPIO_Init(GPIOA, &gpio);
HAL_GPIO_Init(GPIOB, &gpio);
HAL_GPIO_Init(GPIOC, &gpio);
HAL_GPIO_Init(GPIOD, &gpio);
HAL_GPIO_Init(GPIOE, &gpio);
HAL_GPIO_Init(GPIOH, &gpio);
gpio.Pin = V1_Pin;
gpio.Mode = GPIO_MODE_INPUT;
gpio.Pull = GPIO_PULLUP; // or GPIO_PULLDOWN
gpio.Pull = GPIO_NOPULL;
HAL_GPIO_Init(GPIOA, &gpio);
HAL_SuspendTick();
HAL_PWREx_EnterSTOP2Mode(PWR_STOPENTRY_WFI);
}
/* USER CODE END 0 */
/**
* @brief The application entry point.
* @retval int
*/
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_USART1_UART_Init();
/* USER CODE BEGIN 2 */
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
printf("entering stop mode\r\n");
Enter_Stop2_Mode();
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
}
/* USER CODE END 3 */
}
Question:
Is this higher current expected when keeping a GPIO input active in STOP2? My power budget is around 10uA.