r4f2426 Renesas Electronics Corporation., r4f2426 Datasheet - Page 261

• Manufacturer Part Number: r4f2426
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2400 Series
• Manufacturer: Renesas Electronics Corporation.

• RAS Up Mode
φ
Address bus
RASn (CSn)
UCAS, LCAS
RD
OE
Data bus
Note: n = 2 to 5
To select RAS up mode, clear the RCDM bit to 0 in DRAMCR. 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 6.45 shows an example of
the timing in RAS up mode.
Figure 6.45 Example of Operation Timing in RAS Up Mode
T
Row address
p
DRAM space read
T
r
(RAST = 0, CAST = 0)
Column address 1 Column address 2
T
c1
T
c2
T
DRAM space
Rev. 1.00 Sep. 19, 2008 Page 233 of 1270
c1
read
T
c2
Section 6 Bus Controller (BSC)
External address
Normal space
T
1
read
REJ09B0466-0100
T
2