Renesas H8S Series Hardware Manual page 174

• RAS up mode
To select RAS up mode, clear the RCDM bit in MCR to 0. Each time access to DRAM space is interrupted and
another space is accessed, the RAS signal goes high again. Burst operation is only performed if DRAM space is
continuous. Figure 6-22 shows an example of the timing in RAS up mode.
In the case of burst ROM space access, the RAS signal is not restored to the high level.
ø
A to A
23
CSn, (RAS)
CAS, LCAS
D to D
15
Note: n = 2 to 5
Rev.6.00 Oct.28.2004 page 146 of 1016
REJ09B0138-0600H
DRAM access
T T
p r
0
0
Figure 6-22 Example of Operation Timing in RAS Up Mode
DRAM access
T T T
c1 c2 c1
External space
access
T T T
c2 1 2