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180
•
Bits 11–10—DRAM Write Cycle Wait Count (DWW1–DWW0): Specifies the number of
DRAM write cycle column address output cycles.
Bit 11 (DWW1)
Bit 10 (DWW0)
Description
0
0
2-cycle (no wait) external wait disabled
(
initial value)
1
3-cycle (1 wait) external wait disabled
1
0
4-cycle (2 wait) external wait enabled
1
5-cycle (3 wait) external wait enabled
•
Bits 9–8—DRAM Read Cycle Wait Count (DWR1–DWR0): Specifies the number of DRAM
read cycle column address output cycles.
Bit 9 (DWR1)
Bit 8 (DWR0)
Description
0
0
2-cycle (no wait) external wait disabled
(
initial value)
1
3-cycle (1 wait) external wait disabled
1
0
4-cycle (2 wait) external wait enabled
1
5-cycle (3 wait) external wait enabled
•
Bit 7—DRAM Idle Cycle Count (DIW): Specifies whether to insert idle cycles, either when
accessing a different external space (CS space) or when doing a DRAM write, after DRAM
reads.
Bit 7 (DIW)
Description
0
No idle cycles (initial value)
1
1 idle cycle
•
Bit 6—Reserved: This bit always reads as 0. The write value should always be 0.
•
Bit 5—Burst Enable (BE): Specifies the DRAM operation mode.
Bit 5 (BE)
Description
0
Burst disabled (initial value)
1
DRAM high-speed page mode enabled
.
•
Bit 4—RAS Down Mode (RASD): Specifies the DRAM operation mode.
Bit 4 (RASD)
Description
0
Access DRAM by RAS up mode (initial value)
1
Access DRAM by RAS down mode
Summary of Contents for SH7041 Series
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