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CHAPTER 22
µ
PD78F0974
22.1 Memory Size Switching Register
The
µ
PD78F0974 allow users to select the internal memory capacity using the memory size switching register (IMS)
so that the same memory map as that of the
µ
PD780973(A) with a different size of internal memory capacity can be
achieved.
IMS is set by using an 8-bit memory manipulation instruction.
RESET input sets IMS to CFH.
Figure 22-1. Memory Size Switching Register (IMS) Format
Address: FFF0H After Reset: CFH R/W
Symbol
7
6
5
4
3
2
1
0
IMS
RAM2
RAM1
RAM0
0
ROM3
ROM2
ROM1
ROM0
RAM2
RAM1
RAM0
Internal High-Speed RAM Capacity Selection
0
0
0
768 bytes
1
1
0
1024 bytes
Other than above
Setting prohibited
ROM3
ROM2
ROM1
ROM0
Internal ROM Capacity Selection
0
1
1
0
24 Kbytes
1
0
0
0
32 Kbytes
Other than above
Setting prohibited
The IMS settings to obtain the same memory map as the
µ
PD780973(A) are shown in Table 22-2.
Table 22-2. Memory Size Switching Register Settings
Product
IMS Setting
µ
PD780973(A)
06H
Caution
With the
µ
PD780973(A), IMS must be set to 06H.
Summary of Contents for mPD780973 Series
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