Renesas 70 - Manual (Page 21)

Chapter 3 Introduction to MR308
- 11 -
Key input
microcomputer
Remote control
microcomputer
LED illumination
microcomputer
Arbiter
microcomputer
Volume control
microcomputer
Monitor
microcomputer
Mechanical
control
microcomputer
Figure 3.2 Microcomputer-based System Example(Audio Equipment)
Using independent microcomputers for various functions as indicated in the above example offers the following
advantages.
1. Individual programs are small so that program development is easy.
2. It is very easy to use previously developed software. 6
3. Completely independent programs are provided for various functions so that program devel-
opment can easily be conducted by a number of engineers.
On the other hand, there are the following disadvantages.
1. The number of parts used increases, thereby raising the product cost.
2. Hardware design is complicated.
3. Product physical size is enlarged.
Therefore, if you employ the real-time OS in which a number of programs to be operated by a number of micro-
computers are placed under software control of one microcomputer, making it appear that the programs run on
separate microcomputers, you can obviate all the above disadvantages while retaining the above-mentioned
advantages.
Figure 3.3 shows an example system that will be obtained if the real-time OS is incorporated in the system indi-
cated in Figure 3.2.
6 In the case presented in エラー! 参照元が見つかりません。 for instance, the remote control microcomputer can be used for other prod-
ucts without being modified.