The SCS includes a system timer, SysTick, that an operating system can use to ease porting from another platform.
Software can poll SysTick, or you can configure it to generate an interrupt. The SysTick interrupt has its own entry in the vector table and therefore can have its own handler.
The following table describes the registers that you use to configure SysTick.
Table 5-3 Registers available for configuring SysTick
|SysTick Control and Status||
||Basic control of SysTick: enable, clock source, interrupt, or poll.|
|SysTick Reload Value||
||Value to load Current Value register when 0 is reached.|
|SysTick Current Value||
||The current value of the count down.|
|SysTick Calibration Value||
||Contains the current value of the count down.|