Renesas 70 User Manual
Chapter 3 Introduction to MR308
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3.3.3
Task Priority and Waiting Queue
In The standard profiles in µITRON 4.0 Specification support two waiting methods for each object. In one
method, tasks are placed in a waiting queue in order of priority (TA_TPRI attribute); in another, tasks are placed
in a waiting queue in order of FIFO (TA_TFIFO).
Figure 3.15 and Figure 3.16 depict the manner in which tasks are placed in a waiting queue in order of
"taskD," "taskC," "taskA," and "taskB."
method, tasks are placed in a waiting queue in order of priority (TA_TPRI attribute); in another, tasks are placed
in a waiting queue in order of FIFO (TA_TFIFO).
Figure 3.15 and Figure 3.16 depict the manner in which tasks are placed in a waiting queue in order of
"taskD," "taskC," "taskA," and "taskB."
n
Priority
1 Priority
5 Priority
6
taskB
1
ID No.
2
taskA
taskC
taskD
Priority 9
Figure 3.15 Waiting queue of the TA_TPRI attribute
n
Priority
9 Priority
6 Priority
1
taskC
1
ID No.
2
taskD
taskA
taskB
Priority 5
Figure 3.16 Waiting queue of the TA_TFIFO attribute