CHAPTER 21 FLASH MEMORY
Preliminary User’s Manual U16846EJ1V0UD
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21.1 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 input sets IMS to CFH.
Caution The initial value of IMS is “setting prohibited (CFH)”. Be sure to set the value shown in Table 21-
2 for each product at initialization. When using the 78K0/KB1+ to evaluate the program of a mask
ROM version of the 78K0/KB1, be sure to set the values shown in Table 21-2.
Figure 21-1. Format of Internal Memory Size Switching Register (IMS)
Address: FFF0H After reset: CFH R/W
Symbol 7 6 5 4 3 2 1 0
IMS
RAM2 RAM1 RAM0
0
ROM3 ROM2 ROM1 ROM0
RAM2 RAM1 RAM0
Internal
high-speed RAM capacity selection
0 0 0
768
bytes
0 1 0
512
bytes
Other than above
Setting prohibited
ROM3 ROM2 ROM1 ROM0
Internal
ROM
capacity
selection
0 0 1 0
8
KB
0 1 0 0
16
KB
0 1 1 0
24
KB
Other than above
Setting prohibited
The IMS settings required to obtain the same memory map as mask ROM versions are shown in Table 21-2.
Table 21-2. Internal Memory Size Switching Register Settings
Flash Memory Version
(78K0/KB1+)
Target Mask ROM Version
(78K0/KB1)
Internal Memory Size
Switching Register (IMS)
µ
PD78F0101H
µ
PD780101 42H
µ
PD78F0102H
µ
PD780102 04H
µ
PD78F0103H
µ
PD780103 06H