Memory Size Switching Register Format; Values When The Memory Size Switching Register Is Reset - NEC PD78056F User Manual

CHAPTER 22 EXTERNAL DEVICE EXPANSION FUNCTION
(2) Memory size switching register (IMS)
This register specifies the internal memory size. In principle, use IMS in a default status. However, when
using the external device expansion function with the PD78058F, 78P058F, 78058FY and 78P058FY, set
IMS so that the internal ROM capacity is 56 Kbytes or lower.
IMS is set with an 8-bit memory manipulation instruction.
RESET input sets this register to the value indicated in Table 22-3.
Figure 22-3. Memory Size Switching Register Format
Symbol 7 6 5
IMS RAM2 RAM1 RAM0
Note The values after reset depend on the product. (See Table 22-3)
Table 22-3. Values When the Memory Size Switching Register Is Reset
4 3 2 1 0
0 ROM3 ROM2 ROM1 ROM0
Part Number
PD78056F, 78056FY
PD78058F, 78058FY
After
Address
Reset
FFF0H Note
ROM3 ROM2 ROM1 ROM0 Internal ROM Size Selection
1 1 0 0 48 Kbytes
1 1 1 0 56 Kbytes
1 1 1 1 60 Kbytes
Other than above Setting prohibited
RAM2 RAM1 RAM0
Internal High-Speed RAM Size Selection
1 1 0 1024 bytes
Other than above Setting prohibited
Reset Value
CCH
CFH
R/W
R/W
509