138
CHAPTER 4 BUS INTERFACE
4.15 Little Endian Register (LER)
When bus access by the MB91F109 is performed, the whole area is usually composed
of big endians. However, setting the little endian register (LER) makes it possible to
handle one of areas 1 to 5 as a little endian area.
This register is supported for all bus modes independently of the usual, time sharing,
and DRAM interfaces. However, area 0 is outside the little endian areas.
■
Configuration of Little Endian Register (LER)
The little endian register (LER) is configured as follows:
■
Bit Functions of Little Endian Register (LER)
As shown in Table 4.15-1, the LE2, LE1, and LE0 bits are combined to specify little endian
areas.
<Note>
Writing to the LER register can be performed only one time after it is reset.
7
6
5
4
3
2
1
0
LER
Address: 0000 07FE
H
LE2
LE1
LE0
-----000
W
Access
Initial value
Table 4.15-1 Mode Setting Using the Combination of Bits (LE2, LE1, and LE0)
LE2
LE1
LE0
Mode
0
0
0
Initial value after reset.
No little endian area exists.
0
0
1
Area 1 is handled as a little endian.
Areas 0 and 2 to 5 are handled as big endians.
0
1
0
Area 2 is handled as a little endian.
Areas 0 to 1 and 3 to 5 are handled as big endians.
0
1
1
Area 3 is handled as a little endian.
Areas 0 to 2 and 4 to 5 are handled as big endians.
1
0
0
Area 4 is handled as a little endian.
Areas 0 to 3 and 5 are handled as big endians.
1
0
1
Area 5 is handled as a little endian.
Areas 0 to 4 are handled as big endians.
Summary of Contents for MB91F109
Page 2: ......
Page 3: ...FUJITSU LIMITED FR30 32 Bit Microcontroller MB91F109 Hardware Manual ...
Page 4: ......
Page 10: ...vi ...
Page 24: ...xx ...
Page 96: ...72 CHAPTER 2 CPU ...
Page 224: ...200 CHAPTER 4 BUS INTERFACE ...
Page 234: ...210 CHAPTER 5 I O PORTS ...
Page 268: ...244 CHAPTER 9 U TIMER ...
Page 290: ...266 CHAPTER 10 UART ...
Page 314: ...290 CHAPTER 12 16 BIT RELOAD TIMER ...
Page 322: ...298 CHAPTER 13 BIT SEARCH MODULE ...
Page 392: ...368 CHAPTER 16 FLASH MEMORY ...
Page 432: ...408 APPENDIX E Instructions F Table E 2 Instruction Formats OP rel11 5 11 ...
Page 448: ...424 APPENDIX E Instructions ...
Page 449: ...425 INDEX INDEX The index follows on the next page This is listed in alphabetic order ...
Page 458: ...434 INDEX ...
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Page 461: ...FUJITSU SEMICONDUCTOR FR30 32 Bit Microcontroller MB91F109 Hardware Manual ...