详细的讲解了STM32单片机的时钟结构，内核时钟，外设时钟如AHB、APB1、APB2、gpio等，能帮助开发者更好的配置单片机的时钟。-Detailed explanation of the the STM32 MCU clock structure, core clock, peripheral clock, such as AHB, APB1, APB2, GPIO, etc., can help developers better configure the MCU clock..........