HD6473032F16 Datasheet, PDF (192/847 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series

Section 7 Refresh Controller
Self-Refresh Mode: Some DRAM devices have a self-refresh function. After the SRFMD bit is
set to 1 in RFSHCR, when a transition to software standby mode occurs, the CAS and RAS
outputs go low in that order so that the DRAM self-refresh function can be used. On exit from
software standby mode, the CAS and RAS outputs both go high.
Table 7.7 shows the pin states in software standby mode. Figure 7.6 shows the signal output
timing.
Table 7.7
Signal
HWR
LWR
RD
CS3
RFSH
Pin States in Software Standby Mode (PSRAME = 0, DRAME = 1)
Software Standby Mode
SRFMD = 0
SRFMD = 1 (self-refresh mode)
CAS/WE = 0
CAS/WE = 1
CAS/WE = 0
CAS/WE = 1
High-impedance High-impedance
High
Low
High-impedance High-impedance
High
Low
High-impedance High-impedance
Low
High
High
High
Low
Low
High
High
Low
Low
Rev. 3.00 Mar 21, 2006 page 162 of 814
REJ09B0302-0300