570
CHAPTER 27
µ
PD78P078, 78P078Y
7
RAM2
Symbol
IMS
6
RAM1
5
RAM0
4
0
3
ROM3
2
ROM2
1
ROM1
0
ROM0
Address
FFF0H
CFH
After
Reset
R/W
R/W
1
1
Internal ROM Capacity Selection
48 Kbytes
56 Kbytes
Note
ROM3
60 Kbytes
1
1
1
ROM2
1
0
1
ROM1
1
0
0
ROM0
1
Setting prohibited
Other than above
Internal High-Speed RAM Capacity Selection
RAM2 RAM1 RAM0
1024 bytes
1
1
0
Setting prohibited
Other than above
27.1 Internal Memory Size Switching Register
The
µ
PD78P078 and 78P078Y allow users to define its internal memory sizes using the internal memory size
switching register (IMS), so that the same memory mapping as that of a mask ROM version with a different-size
internal ROM is possible.
IMS is set with an 8-bit memory manipulation instruction.
RESET input sets IMS to CFH.
Figure 27-1. Internal Memory Size Switching Register Format
Note
When using the external device extension function on the following devices, the internal ROM capacity
must be 56 Kbytes or less:
µ
PD78078, 78078Y, 78P078, 78P078Y.
Caution When using the mask ROM versions, do not set the values other than CCH and CFH to the IMS
except for the case where the external device extension function is used on the
µ
PD78078 and
78078Y.
The IMS settings to give the same memory map as mask ROM versions are shown in Table 27-2.
Table 27-2. Examples of Internal Memory Size Switching Register Settings
Relevant Mask ROM Version
IMS Setting
µ
PD78076, 78076Y
CCH
µ
PD78078, 78078Y
CFH
Summary of Contents for PD78076
Page 2: ...2 MEMO ...
Page 12: ...12 MEMO ...
Page 48: ...48 MEMO ...
Page 64: ...64 MEMO ...
Page 82: ...82 MEMO ...
Page 100: ...100 MEMO ...
Page 130: ...130 MEMO ...
Page 180: ...180 MEMO ...
Page 222: ...222 MEMO ...
Page 248: ...248 MEMO ...
Page 288: ...288 MEMO ...
Page 308: ...308 MEMO ...
Page 364: ...364 MEMO ...
Page 494: ...494 MEMO ...
Page 526: ...526 MEMO ...
Page 544: ...544 MEMO ...
Page 558: ...558 MEMO ...
Page 580: ...580 MEMO ...
Page 596: ...596 MEMO ...
Page 598: ...598 MEMO ...
Page 626: ...626 MEMO ...