126
CHAPTER 4 BUS INTERFACE
4.9
Area Mode Register 5 (AMD5)
Area mode register 5 (AMD5) specifies the bus mode of chip select area 5 (area
specified by ASR5 and AMR5).
Area 5 allows the use of the DRAM interface.
■
Configuration of Area Mode Register 5 (AMD5)
Area mode register 5 (AMD5) is configured as follows:
■
Bit Functions of Area Mode Register 5 (AMD5)
[bit 7] DRME (DRaM Enable bit)
The DRME bit selects the usual bus interface or DRAM interface for area 5.
0: Usual bus interface
1: DRAM interface
When the DRAM interface is used, more details must be specified via the DMCR (DRAM
control register) described later.
[bit 4 and 3] BW1 and 0 (Bus Width bit)
BW1 and BW0 specify the bus width of area 5. These bits have functions similar to those of
the BW bits of other AMD registers. When the DRAM interface is used, the bus width
specified by these bits is also valid.
[bit 2 to 0] WTC 2 to 0 (Wait Cycle bit)
WTC2 to WTC0 specify the number of wait cycles to be automatically inserted when area 5
is accessed via memory.
These bits have functions similar to those of the WTC bits of other AMD registers. By
resetting these bits to "000", the number of wait cycles to be automatically inserted becomes
"0".
When the DRAM interface is used because wait cycles are controlled by the DMCR, WTC2
to WTC0 become invalid.
7
6
5
4
3
2
1
0
AMD5
0624
H
DRME
BW1
BW0 WTC2 WTC1 WTC0
0--00000
R/W
Address: 0000
Initial value
Access
BW1
BW0
Bus width
0
0
1
1
0
1
0
1
8 bits
16 bits
Setting disabled
Reserved
Summary of Contents for MB91F109
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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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