Chapter 3 Introduction to MR308
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3.5.2 Module Overview

The MR308 kernel modules are outlined below.
• Scheduler
Forms a task processing queue based on task priority and controls operation so that the high-priority
task at the beginning in that queue (task with small priority value) is executed.
• Task Management Module
Exercises the management of various task states such as the RUNNING, READY, WAIT, and SUS-
PENDED state.
• Task Synchronization Module
Accomplishes inter-task synchronization by changing the task status from a different task.
• Interrupt Management Module
Makes a return from the interrupt handler.
• Time Management Module
Sets up the system timer used by the MR308 kernel and starts the user-created alarm handler30 and
cyclic handler.31.
• System Status Management Module
Gets the system status of MR308.
• System Configuration Management Module
Reports the MR308 kernel version number or other information.
• Sync/Communication Module
This is the function for synchronization and communication among the tasks. The following three func-
tional modules are offered.
♦ Eventflag
Checks whether the flag controlled within the MR308 is set up and then determines whether or not
to initiate task execution. This results in accomplishing synchronization between tasks.
♦ Semaphore
Reads the semaphore counter value controlled within the MR308 and then determines whether or
not to initiate task execution. This also results in accomplishing synchronization between tasks.
♦ Mailbox
Provides inter-task data communication by delivering the first data address.
♦ Data queue
Performs 32-bit data communication between tasks.
• Memory pool Management Module
Provides dynamic allocation or release of a memory area used by a task or a handler.
• Extended Function Module
Outside the scope of µITRON 4.0 Specification , this function performs reset processing on short data
queues and objects.
30 This handler actuates once only at preselected times.
31 This handler periodically actuates.