Page 380 - ARM Based Microcontroller Projects Using MBED

366 15. Mbed RTOS PROJECTS

FIG. 15.2 Example Round Robin scheduling with three tasks.

FIG. 15.3 Example IB scheduling with three tasks.

scheduling are that it is complex to implement, and also there is too much overhead in terms
of context saving and restoring. Fig. 15.3 shows an example IB type scheduling with three
tasks where Task1 has the lowest priority and Task2 has the highest priority.

15.3 Mbed RTOS IMPLEMENTATION

One of the nice features of Mbed is that it supports preemptive interrupt-based scheduling.
Several tasks can be given different priorities, they can be scheduled to start, stop, commu-
nicate with other, and share resources. We shall be developing several multitasking projects
in the next sections using various Mbed RTOS functions. Note that the RTOS features described
in this book refer to Mbed OS 2. Other OS versions may have different functions and features.

15.4 PROJECT 1—DIFFERENT FLASHING A PAIR OF LEDs—USING
Mbed THREAD

15.4.1 Description

In this project two LEDs (LEDA and LEDB) are connected to the Nucleo-F411RE develop-
ment board. The project flashes LEDA every second, and LEDB every 0.5s.

15.4.2 Aim

This is a multitasking project having two tasks. The aim of this project is to show how two
tasks can be created using Mbed function Thread.