r4f2456 Renesas Electronics Corporation., r4f2456 Datasheet - Page 268

• Manufacturer Part Number: r4f2456
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2400 Series
• Manufacturer: Renesas Electronics Corporation.

Section 6 Bus Controller (BSC)
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.
Rev. 1.00 Sep. 19, 2008 Page 238 of 1342
REJ09B0467-0100
CSn (RASn)
φ
UCAS, CAS
T
Rp
(RCW1 = 0, RCW0 = 1, RLW1 = 0, RLW0 = 0)
Figure 6.49 CBR Refresh Timing
T
Rrw
T
Rr
T
Rc1
T
Rc2