Chapter 26 Flash Memory; Internal Memory Size Switching Register - NEC 78K0 Series User Manual

The 78K0/KE2 incorporates the flash memory to which a program can be written, erased, and overwritten while
mounted on the board.

26.1 Internal Memory Size Switching Register

The internal memory capacity can be selected using the internal memory size switching register (IMS).
IMS is set by an 8-bit memory manipulation instruction.
Reset signal generation sets IMS to CFH.
Caution Be sure to set each product to the values shown in Table 26-1 after a reset release.
Figure 26-1. Format of Internal Memory Size Switching Register (IMS)
Address: FFF0H After reset: CFH
Symbol 7
IMS RAM2
RAM2
0
1
ROM3
0
0
1
1
1
Caution To set the memory size, set IMS and then IXS. Set the memory size so that the internal ROM and
internal expansion RAM areas do not overlap.
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CHAPTER 26 FLASH MEMORY

R/W
6 5
RAM1 RAM0
RAM1 RAM0
0 0
1 0
Other than above
ROM2 ROM1
1 0
1 1
0 0
1 0
1 1
Other than above
Preliminary User's Manual U17260EJ3V1UD
4 3
0 ROM3
Internal high-speed RAM capacity selection
768 bytes
1024 bytes
Setting prohibited
ROM0 Internal ROM capacity selection
0 16 KB
0 24 KB
0 32 KB
0 48 KB
1 60 KB
Setting prohibited
2 1
ROM2 ROM1 ROM0
0