r4f2426 Renesas Electronics Corporation., r4f2426 Datasheet - Page 249

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

6.7.6
The column address output cycle can be changed from 2 states to 3 states by setting the CAST bit
to 1 in DRAMCR. Use the setting that gives the optimum specification values (CAS pulse width,
etc.) according to the DRAM connected and the operating frequency of this LSI. Figure 6.34
shows an example of the timing when a 3-state column address output cycle is selected.
Read
Write
Note: n = 2 to 5
Figure 6.34 Example of Access Timing with 3-State Column Address Output Cycle
Column Address Output Cycle Control
φ
Address bus
RASn (CSn)
UCAS, LCAS
WE (HWR)
OE (RD)
Data bus
WE (HWR)
OE (RD)
Data bus
T
p
Row address
(RAST = 0)
High
High
T
r
T
c1
Rev. 1.00 Sep. 19, 2008 Page 221 of 1270
Column address
T
Section 6 Bus Controller (BSC)
c2
T
REJ09B0466-0100
c3