【嵌入式系統放牛班】System Tick0:00 Program Timer-030:44 Timer Tick5:33 計時器刻度重點整理7:04 Arm Cortex-M Systick (System Tick)10:26 Systick Control Register11:45 Operating System Tick (FreeRTOS)17:05 Software Timer API18:50 Hardware Timer ISR