freertos_mutex
Overview
This document explains the freertos_mutex example. It shows how mutex manage access to common resource (terminal output).
The example application creates two identical instances of write_task. Each task will lock the mutex before printing and unlock it after printing to ensure that the outputs from tasks are not mixed together.
The test_task accept output message during creation as function parameter. Output message have two parts. If xMutex is unlocked, the write_task_1 acquire xMutex and print first part of message. Then rescheduling is performed. In this moment scheduler check if some other task could run, but second task write_task+_2 is blocked because xMutex is already locked by first write task. The first write_task_1 continue from last point by printing of second message part. Finaly the xMutex is unlocked and second instance of write_task_2 is executed.
Running the demo
After the board is flashed the Tera Term will start periodically printing strings synchronized by mutex.
Example output: “ABCD | EFGH” “1234 | 5678” “ABCD | EFGH” “1234 | 5678”