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Section 13 Bus State Controller (BSC)
SH7751 Group, SH7751R Group
Page 448 of 1128
R01UH0457EJ0301 Rev. 3.01
Sep 24, 2013
RTCNT value
RTCOR-1
H'00000000
RTCSR.CKS2–0
External bus
Refresh request cleared
by start of refresh cycle
= 000
≠
000
RTCNT cleared to 0 when
RTCNT = RTCOR
Auto-refresh cycle
Time
Refresh
request
Figure 13.35 Auto-Refresh Operation
TRr2
TRr3
TRr4
TRr5
Trc
TRr1
Trc
TRrw
Trc
CKIO
CSn
RD/
WR
RAS
DQMn
BS
CKE
D31–D0
CASS
Figure 13.36 Synchronous DRAM Auto-Refresh Timing