78F0988 View Datasheet(PDF) - NEC => Renesas Technology
Part Name
Description
Manufacturer
78F0988 Datasheet PDF : 52 Pages
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µPD78F0988A, 78F0988A(A)
4. INTERNAL MEMORY SIZE SWITCHING REGISTER (IMS)
IMS is a register that is set by software and is used to specify a part of the internal memory that is not to be used.
By setting this register, the internal memory of the µPD78F0988A and µPD78F0988 can be mapped in the same
manner as that of a mask ROM version with a different internal memory (ROM and RAM) capacity.
IMS is set with an 8-bit memory manipulation instruction.
IMS is set to CFH by RESET input.
Figure 4-1. Format of Internal Memory Size Switching Register
7
6
5
4
3
2
1
0
Address After reset R/W
IMS RAM2 RAM1 RAM0 0 ROM3 ROM2 ROM1 ROM0 FFF0H
CFH
R/W
ROM3 ROM2 ROM1 ROM0 Selection of internal
ROM capacity
0
1
0
0 16 KB
0
1
1
0 24 KB
1
0
0
0 32 KB
1
1
0
0 48 KB
1
1
1
1 60 KB
Other than above
Setting prohibited
RAM2 RAM1 RAM0 Selection of internal
high-speed RAM capacity
1
1
0
Other than above
1024 bytes
Setting prohibited
Table 4-1 shows the IMS setting values to make the memory mapping the same as that of mask ROM versions.
Table 4-1. Setting Value of Internal Memory Size Switching Register
Target Mask ROM Versions
µPD780982
µPD780983
µPD780984
µPD780986
µPD780988
IMS Setting Value
C4H
C6H
C8H
CCH
CFH
Data Sheet U15801EJ1V0DS
17
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