HD64F2357F20V Datasheet, PDF (176/1049 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-chip Microcomputer H8S Family / H8S/2300 Series

• 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.
DRAM access
DRAM access
External space
access
T_p
T_r
T_c1
T_c2
T_c1
T_c2
T₁
T₂
ø
A₂₃ to A₀
CSn, (RAS)
CAS, LCAS
D₁₅ to D₀
Note: n = 2 to 5
Figure 6-22 Example of Operation Timing in RAS Up Mode
Rev.6.00 Oct.28.2004 page 146 of 1016
REJ09B0138-0600H