SWRU543B January 2019 – June 2025 CC3230S , CC3230SF , CC3235MODS , CC3235MODSF , CC3235S , CC3235SF
The Arm® Cortex®-M4 processor core includes an integrated system timer, SysTick. SysTick provides a simple, 24-bit, clear-on-write, decrementing, wrap-on-zero counter with a flexible control mechanism. The counter is clocked on the system clock.
SysTick makes OS porting between Cortex®-M4 devices much easier because there is no need to change the OS system timer code. The SysTick timer integrates with the NVIC and can generate a SysTick exception (exception type 15). In many OSs, a hardware timer generates interrupts so that the OS can perform task management (for example, to allow multiple tasks to run at different time slots and to ensure that no single task can lock up the entire system). To perform this function, the timer must be able to generate interrupts and, if possible, be protected from user tasks so that user applications cannot change the timer behavior.
The counter can be used in several different ways: