要了解一款MCU，首先需要知道就是其ROM空间、RAM空间、IO口数量、定时器数量和定时方式、所提供的外围功能模块（Peripheral Circuit）、中断源、工作电压及功耗等等。-For an MCU, you first need to know is its ROM space, RAM space, IO port number, quantity and timing timer mode, the external function modules provided by (Pe