HD64F3048F16 Datasheet, PDF (215/903 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 7 Refresh Controller
Self-Refresh Mode
Some pseudo-static RAM 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 H8/3048B Group’s CS₃ output
goes high and its RFSH output goes low so that the pseudo-static RAM self-refresh function can
be used. On exit from software standby mode, the RFSH output goes high.
Table 7.8 shows the pin states in software standby mode. Figure 7.16 shows the signal output
timing.
Table 7.8 Pin States in Software Standby Mode (2) (PSRAME = 1, DRAME = 0)
Signal
CS
3
RD
HWR
LWR
RFSH
SRFMD = 0
High
High-impedance
High-impedance
High-impedance
High
Software Standby Mode
SRFMD = 1 (Self-Refresh Mode)
High
High-impedance
High-impedance
High-impedance
Low
φ
Address
bus
CS₃
RD
High
HWR
LWR
RFSH
Software standby mode
Oscillator
settling time
High-impedance
High-impedance
High-impedance
High-impedance
Figure 7.16 Signal Output Timing in Self-Refresh Mode (PSRAME = 1, DRAME = 0)
Rev. 3.00 Sep 27, 2006 page 187 of 872
REJ09B0325-0300