Renesas M3T-MR100 用户手册
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3.
Introduction to Kernel
3.1 Concept of Real-time OS
This section explains the basic concept of real-time OS.
3.1.1
Why Real-time OS is Necessary
In line with the recent advances in semiconductor technologies, the single-chip microcomputer ROM capacity has in-
creased. ROM capacity of 32K bytes.
creased. ROM capacity of 32K bytes.
As such large ROM capacity microcomputers are introduced, their program development is not easily carried out by con-
ventional methods. Figure 3.1 shows the relationship between the program size and required development time (program
development difficulty).
ventional methods. Figure 3.1 shows the relationship between the program size and required development time (program
development difficulty).
This figure is nothing more than a schematic diagram. However, it indicates that the development period increases expo-
nentially with an increase in program size.
nentially with an increase in program size.
For example, the development of four 8K byte programs is easier than the development of one 32K byte program.
Program Size
Kbyte
4
8
16
32
Development Period
Figure 3.1 Relationship between Program Size and Development Period
Under these circumstances, it is necessary to adopt a method by which large-size programs can be developed within a short
period of time. One way to achieve this purpose is to use a large number of microcomputers having a small ROM capacity.
Figure 3.2 presents an example in which a number of microcomputers are used to build up an audio equipment system.
period of time. One way to achieve this purpose is to use a large number of microcomputers having a small ROM capacity.
Figure 3.2 presents an example in which a number of microcomputers are used to build up an audio equipment system.
4
On condition that the ROM program burning step need not be performed.