µPD178023, 178024
2.1 Memory Size Select Register (IMS)
The memory size select register (IMS) sets the internal memory capacity.
Set the µPD178023, µPD178024 to C6H, C8H respectively.
Use an 8-bit memory manipulation instruction to set the IMS.
This register is set to CFH at reset.
Caution Be sure to set the IMS to C6H or C8H as the program initial setting. The IMS set value changes
to CFH when reset. Therefore, set C6H or C8H again after reset.
Figure 2-2. Format of Memory Size Select Register (IMS)
Symbol
7
6
5
4
0
3
2
1
0
Address
FFF0H
At reset
CFH
R/W
R/W
IMS RAM2 RAM1 RAM0
ROM3 ROM2 ROM1 ROM0
RAM2 RAM1 RAM0
Selects Internal High-speed RAM Capacity
1
1
0
1024 bytes
Others
Setting prohibited
RAM3 RAM2 RAM1 RAM0
Selects Internal ROM Capacity
0
1
0
1
0
0
0
24K bytes
32K bytes
1
Others
Setting prohibited
Table 2-1 indicates the setting of IMS.
Table 2-1. Set Value of Memory Size Select Register (IMS)
Targeted Model
µPD178023
µPD178024
Set Value of IMS
C6H
C8H
Data Sheet U14126EJ1V0DS00
17
NEC [ NEC ]
