r4f2426 Renesas Electronics Corporation., r4f2426 Datasheet - Page 265

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

Depending on the DRAM used, modification of the WE signal may not be permitted during the
refresh period. In this case, the CBRM bit in REFCR should be set to 1. The bus controller will
then insert refresh cycles in appropriate breaks between bus cycles. Figure 6.50 shows an example
of the timing when the CBRM bit is set to 1. In this case the CS signal is not controlled, and
retains its value prior to the start of the refresh period.
φ
A23 to A0
CS
AS
RD
HWR (WE)
RAS
CAS
Figure 6.50 Example of CBR Refresh Timing (CBRM = 1)
Normal space access request
Refresh period
Rev. 1.00 Sep. 19, 2008 Page 237 of 1270
Section 6 Bus Controller (BSC)
REJ09B0466-0100