UPD78F0138 NEC, UPD78F0138 Datasheet - Page 437

• Manufacturer Part Number: UPD78F0138
• Description: (UPD78xxxx) 8-Bit Single-Chip Microcontrollers
• Manufacturer: NEC

27.1 Internal Memory Size Switching Register
switching register (IMS) so that the same memory map as that of the mask ROM versions with a different internal
memory capacity can be achieved.
The
IMS is set by an 8-bit memory manipulation instruction.
RESET input sets IMS to CFH.
Cautions 1. Be sure to set the value of the relevant mask ROM version at initialization.
The IMS settings required to obtain the same memory map as mask ROM versions are shown in Table 27-2.
Cautions 1. When using a mask ROM version, be sure to set the value indicated in Table 27-2 to IMS.
Address: FFF0H
Symbol
IMS
µ
PD78F0134 and 78F0138 allow users to select the internal memory capacity using the internal memory size
2. The
2. The
RAM2
RAM2
ROM3
Figure 27-1. Format of Internal Memory Size Switching Register (IMS)
µ
µ
7
0
1
0
0
0
1
1
1
After reset: CFH
PD78F0134 does not support the
PD78F0134 does not support the
Table 27-2. Internal Memory Size Switching Register Settings
Other than above
RAM1
RAM1
ROM2
Other than above
6
1
1
0
1
1
0
1
1
µ
µ
µ
µ
µ
µ
Target Mask ROM Versions
PD780131
PD780132
PD780133
PD780134
PD780136
PD780138
R/W
CHAPTER 27
RAM0
RAM0
ROM1
User’s Manual U16228EJ2V0UD
5
0
0
1
0
1
0
0
1
512 bytes
1024 bytes
Setting prohibited
µ
ROM0
PD78F0134, 78F0138
0
0
0
0
0
0
1
4
µ
µ
PD780136 and 780138.
PD780136 and 780138.
Internal high-speed RAM capacity selection
8 KB
16 KB
24 KB
32 KB
48 KB
60 KB
Setting prohibited
IMS Setting
ROM3
CCH
3
C6H
C8H
CFH
42H
44H
Internal ROM capacity selection
ROM2
2
ROM1
1
ROM0
0
437