UPD78P083GB-3BS-MTX-A Datasheet, PDF (20/58 Pages) Renesas Technology Corp – 8-BIT SINGLE-CHIP MICROCONTROLLER

µPD78P083
3. INTERNAL MEMORY SIZE SWITCHING REGISTER (IMS)
This is a register to disable use of part of internal memories by software. By setting this internal memory size switching
register (IMS), it is possible to get the same memory mapping as that of the mask ROM versions with a different internal
memory (ROM, RAM).
IMS is set with an 8-bit memory manipulation instruction.
RESET input sets IMS to 46H.
Figure 3-1. Internal Memory Size Switching Register Format
Symbol 7
6
5
4
3
2
1
0
Address After Reset
R/W
IMS
RAM2 RAM1 RAM0 0 ROM3 ROM2 ROM1 ROM0
FFF0H
46H
R/W
ROM3 ROM2 ROM1 ROM0 ^{Selection of Internal}
ROM Capacity
0
0
1
0
8 Kbytes
0
1
0
0
16 Kbytes
0
1
1
0
24 Kbytes
Other than above
Setting prohibited
RAM2 RAM1 RAM0 Selection of Internal
High-Speed RAM Capacity
0
1
0 512 bytes
0
1
1 384 bytes
1
0
0 256 bytes
Other than above Setting prohibited
Table 3-1 shows the setting values of IMS which make the memory mapping the same as that of the mask ROM version.
Table 3-1. Internal Memory Size Switching Register Setting Values
Target Mask ROM Versions
µPD78081
µPD78082
IMS Setting Value
82H
64H
18