181
4.17 Bus Timing
4.17.12 Automatic Wait Cycles in Usual DRAM Interface
This section provides an automatic wait cycle timing chart in the usual DRAM
interface.
■
Automatic Wait Cycle Timing Chart in Usual DRAM Interface
❍
Bus width: 8 bits, access: bytes
Figure 4.17-24 Example of Automatic Wait Cycle Timing Chart in Usual DRAM Interface
[Explanation of operation]
•
When adding only one wait clock cycle to the Q1 and Q4 cycles, set the Q1W and Q4W bits
of DMCR4 and DMCR5. The inserted cycles are called the "Q1W" and "Q4W" cycles.
The Q1W and Q4W cycles execute the same cycles as the Q1 and Q4 cycles. By this
operation, the "H" width of RAS and the "L" width of CAS can be extended by one cycle,
respectively.
Set the widths according to the DRAM access time.
Q1
Q1W
Q2
Q3
Q4
Q4W
Q5
CLK
1)Read
A24-00
X
#0 row.adr.
#0 col.adr.
D31-24
#0
D23-16
RAS
CAS
WE
RDX
2)Write
A24-00
X
#0 row.adr.
#0 col.adr.
D31-24
#0
D23-16
RAS
CAS
WE
RDX
Q1 wait
Q4 wait
Usual DRAM interface
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 ...