ESMT
M13S128324A
Precharge
The precharge command is used to precharge or close a bank that has activated. The precharge command is issued when
CS , RAS and WE are low and CAS is high at the rising edge of the clock. The precharge command can be used to
precharge each bank respectively or all banks simultaneously. The bank select addresses (BA0, BA1) are used to define which
bank is precharged when the command is initiated. For write cycle, tWR(min.) must be satisfied until the precharge command
can be issued. After tRP from the precharge, an active command to the same bank can be initiated.
Burst Selection for Precharge by Bank address bits
A8/AP
BA1
0
BA0
0
Precharge
Bank A Only
Bank B Only
Bank C Only
Bank D Only
All Banks
0
0
0
0
1
0
1
1
0
1
1
X
X
NOP & Device Deselect
The device should be deselected by deactivating the CS signal. In this mode DDR SDRAM should ignore all the control
inputs. The DDR SDRAMs are put in NOP mode when CS is active and by deactivating RAS , CAS and WE . For both
Deselect and NOP the device should finish the current operation when this command is issued.
Elite Semiconductor Memory Technology Inc.
Publication Date : Jul. 2009
Revision : 2.3 13/50
ESMT [ ELITE SEMICONDUCTOR MEMORY TECHNOLOGY INC. ]
