RTOS System - Introduction and Test of Tickless Mode
overview
The previous section described the method of counting CPU utilization in RTOS systems . When the CPU is idle, the idle task will be entered . In some simple applications, the device spends most of its time performing idle tasks . It would be nice to put the processor in a low-power mode to reduce energy consumption when entering an idle task. Reducing power consumption saves power and even prolongs the life of the device.
As described in the section RTOS Time Management - Understanding Time-related Concepts in RTOS . The system clock of the RTOS is provided by the SysTick tick timer interrupt. The higher the system clock frequency, the higher the tick timer interrupt frequency. The device frequently handles the interrupt program, which will lead to higher power consumption. However, if the interrupt frequency is too low, it will lead to untimely task switching and affect the real-time performance of the system.
Therefore, in order to reduce power consumption without changing the SysTick interrupt frequency, the RTOS provides a Tickless mode, which turns off the system tick interrupt (tick timer interrupt) when the processor enters the idle task, and only when other interrupts When an event occurs or other tasks need to be processed, the processor