STM32L4 PVD configuration
Hello there,
I am using the STM32L4 family MCU. In my hardware design, only after the USB cable is connected the voltage is applied to the VDD_USB pin of the MCU. At no USB connection this voltage is not present.
As a follow-up to this discussion, I am trying to configure everything now:
https://community.st.com/0D50X00009XkhQCSAZ
My problem consists of 2 sub-problems:
- I cannot get the PVM1 (EXTI35) interrupts to work.
- I dont know what is the PVM1 wakeup time.
The procedure described in the datasheet is as follows:
What I do is the following:
- I enable the PVM1 interrupt:
In the generated code I see it is enabled:
/**
* Initializes the Global MSP. */void HAL_MspInit(void){ /* USER CODE BEGIN MspInit 0 *//* USER CODE END MspInit 0 */
__HAL_RCC_SYSCFG_CLK_ENABLE();
__HAL_RCC_PWR_CLK_ENABLE();HAL_NVIC_SetPriorityGrouping(NVIC_PRIORITYGROUP_4);
/* System interrupt init*/
/* MemoryManagement_IRQn interrupt configuration */ HAL_NVIC_SetPriority(MemoryManagement_IRQn, 0, 0); /* BusFault_IRQn interrupt configuration */ HAL_NVIC_SetPriority(BusFault_IRQn, 0, 0); /* UsageFault_IRQn interrupt configuration */ HAL_NVIC_SetPriority(UsageFault_IRQn, 0, 0); /* SVCall_IRQn interrupt configuration */ HAL_NVIC_SetPriority(SVCall_IRQn, 0, 0); /* DebugMonitor_IRQn interrupt configuration */ HAL_NVIC_SetPriority(DebugMonitor_IRQn, 0, 0); /* PendSV_IRQn interrupt configuration */ HAL_NVIC_SetPriority(PendSV_IRQn, 15, 0); /* SysTick_IRQn interrupt configuration */ HAL_NVIC_SetPriority(SysTick_IRQn, 15, 0);/* Peripheral interrupt init */
/* PVD_PVM_IRQn interrupt configuration */ HAL_NVIC_SetPriority(PVD_PVM_IRQn, 5, 0); HAL_NVIC_EnableIRQ(PVD_PVM_IRQn);/* USER CODE BEGIN MspInit 1 */
/* USER CODE END MspInit 1 */
}2. I enable the PVM1:
/**
* @brief Enable the Power Voltage Monitoring 1: VDDUSB versus 1.2V. * @retval None */void HAL_PWREx_EnablePVM1(void){ SET_BIT(PWR->CR2, PWR_PVM_1); }3. Now I need to wait the ''PVM1 wakeup time'' but since I have no idea what is this time or I cant wait for the PVM1 interrupt as it doesnt work (I dont know why) I am stuck.
The PVM1 interrupt should work when I apply or remove voltage from VDD_USB if I understand correctly. For me it does not. Also the datasheet doesnt specify at any point what is the ''PVM1 wakeup time''.
When I use the debugger I see that the program acts as there is power (even though I do not supply it) but after I stop on the next line, I can see in the PWR_SR2 register that the flag is correct. It feels like its already to late when I stop with debugger and the flag changes...
As a prove, let me show you this case:
I have no USB cable connected, thus VDD_USB is near 0 V. This function returns ''true'':
bool usbds_isPowerPresent()
{ return (!HAL_IS_BIT_SET(PWR->SR2, PWR_SR2_PVMO1));}Now, this modified version of the function returns false:
bool usbds_isPowerPresent()
{ volatile uint32_t dummy = HAL_IS_BIT_SET(PWR->SR2, PWR_SR2_PVMO1); (void)dummy; return (!HAL_IS_BIT_SET(PWR->SR2, PWR_SR2_PVMO1));}This happends because there is more time between Enabling PVM1 and reading the register. But what is that time?
I would appreciate all help regarding this issue. Are there any additional steps I should take to make this work?
#usb