Hitachi H8S/2378, H8S/2378R Series Hardware Manual page 246

T T T T T
Rp Rr Rr1 Rcw Rc2
ø
SDRAMø
Address bus
Precharge-sel
CKE
High
NOP
PALL REF
Figure 6.56 Auto Refresh Timing
(TPC = 0, TPC0 = 0, RLW1 = 0, RLW0 = 1)
Self-Refreshing: A self-refresh mode (battery backup mode) is provided for synchronous DRAM
as a kind of standby mode. In this mode, refresh timing and refresh addresses are generated within
the synchronous DRAM.
To select self-refreshing, set the RFSHE bit to 1 in REFCR. When a SLEEP instruction is
executed to enter software standby mode, the SELF command is issued, as shown in figure 6.57.
When software standby mode is exited, the SLFRF bit in REFCR is cleared to 0 and self-refresh
mode is exited automatically. If an auto refresh request occurs when making a transition to
software standby mode, auto refreshing is executed, then self-refresh mode is entered.
When using self-refresh mode, the OPE bit must not be cleared to 0 in SBYCR.
Rev. 1.0, 09/01, page 202 of 904