ESMT
M13S128324A
1. For the earliest possible Precharge command following a Write burst without interrupting the burst, the minimum time for
write recovery is defined by tWR
.
2. When a precharge command interrupts a Write burst operation, the data mask pin, DQ, is used to mask input data during
the time between the last valid write data and the rising clock edge in which the Precharge command is given. During this
time, the DQS input is still required to strobe in the state of DM.
The minimum time for write recovery is defined by tWR
.
3. For a Write with autoprecharge command, a new Bank Activate command may be issued to the same bank after tWR + tRP
where tWR + tRP starts on the falling DQS edge that strobed in the last valid data and ends on the rising clock edge that
strobes in the Bank Activate commands. During write with autoprecharge, the initiation of the internal precharge occurs at
the same time as the earliest possible external Precharge command without interrupting the Write burst as described in 1
above.
4. In all cases, a Precharge operation cannot be initiated unless tRAS(min) [minimum Bank Activate to Precharge time] has
been satisfied. This includes Write with autoprecharge commands where tRAS(min) must still be satisfied such that a Write
with autoprecharge command has the same timing as a Write command followed by the earliest possible Precharge
command which does not interrupt the burst.
Burst Stop
The burst stop command is initiated by having RAS and CAS high with CS and WE low at the rising edge of the
clock (CLK). The burst stop command has the fewest restriction making it the easiest method to use when terminating a burst
read operation before it has been completed. When the burst stop command is issued during a burst read cycle, the pair of
data and DQS (Data Strobe) go to a high impedance state after a delay which is equal to the CAS latency set in the mode
register. The burst stop command, however, is not supported during a write burst operation.
<Burst Length = 4, CAS Latency = 3 >
0
1
2
3
4
5
6
7
8
C L K
C L K
N OP
C OM MAN D
R EAD A
N OP
N OP
N OP
N OP
Burst Stop
N OP
N OP
D QS
C A S L a t e n cy = 3
D Q' s
Dout
0 Dout 1
Elite Semiconductor Memory Technology Inc.
Publication Date : May. 2007
Revision : 1.8 23/49
ESMT [ ELITE SEMICONDUCTOR MEMORY TECHNOLOGY INC. ]
