Internal Expansion Ram Size Switching Register - NEC 78K0 Series User Manual

8-bit single-chip microcontrollers
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26.2 Internal Expansion RAM Size Switching Register

The internal expansion RAM capacity can be selected using the internal expansion RAM size switching register
(IXS).
IXS is set by an 8-bit memory manipulation instruction.
Reset signal generation sets IXS to 0CH.
Caution Be sure to set each product to the values shown in Table 26-2 after a reset release.
Figure 26-2. Format of Internal Expansion RAM Size Switching Register (IXS)
Address: FFF4H
After reset: 0CH
Symbol
7
IXS
0
IXRAM4
0
0
0
0
0
Caution To set memory size, set IMS and then IXS. Set memory size so that the internal ROM area and
internal expansion RAM area do not overlap.
Table 26-2. Internal Expansion RAM Size Switching Register Settings
Flash Memory Versions (78K0/KE2)
µ
PD78F0531
µ
PD78F0532
µ
PD78F0533
µ
PD78F0534
µ
PD78F0535
µ
PD78F0536
µ
PD78F0537, 78F0537D
560
CHAPTER 26 FLASH MEMORY
R/W
6
5
0
0
IXRAM4
IXRAM3
IXRAM2
IXRAM1
1
1
1
0
1
0
0
1
0
0
Other than above
Preliminary User's Manual U17260EJ3V1UD
4
3
2
IXRAM3
IXRAM2
IXRAM0
Internal expansion RAM capacity selection
0
0
0 byte
1
0
1024 bytes
0
0
2048 bytes
0
0
4096 bytes
0
0
6144 bytes
Setting prohibited
IXS Setting
0CH
0AH
08H
04H
00H
1
0
IXRAM1
IXRAM0

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