STM32的HAL库确实提供了毫秒级的延时函数，即HAL_Delay()函数。这个函数使用SysTick定时器来实现延时，并且可以配置为微秒级的延时。

//stm32l4xx_hal.c
/*** @brief This function provides minimum delay (in milliseconds) based*        on variable incremented.* @note In the default implementation , SysTick timer is the source of time base.*       It is used to generate interrupts at regular time intervals where uwTick*       is incremented.* @note This function is declared as __weak to be overwritten in case of other*       implementations in user file.* @param Delay  specifies the delay time length, in milliseconds.* @retval None*/
__weak void HAL_Delay(uint32_t Delay)
{uint32_t tickstart = HAL_GetTick();uint32_t wait = Delay;/* Add a period to guaranty minimum wait */if (wait < HAL_MAX_DELAY){wait += (uint32_t)uwTickFreq;}while ((HAL_GetTick() - tickstart) < wait){}
}