128Mb: x4, x8, x16
SDRAM
PRECHARGE command is that it requires that the com-
mand and address buses be available at the appropriate
time to issue the command; the advantage of the
PRECHARGE command is that it can be used to truncate
fixed-length or full-page bursts.
Full-page READ bursts can be truncated with the
BURST TERMINATE command, and fixed-length READ
burstsmaybetruncatedwithaBURSTTERMINATEcom-
mand, provided that auto precharge was not activated.
The BURST TERMINATE command should be issued x
cycles before the clock edge at which the last desired data
element is valid, where x equals the CAS latency minus
one. This is shown in Figure 12 for each possible CAS
latency; data element n + 3 is the last desired data ele-
ment of a longer burst.
T0
T1
T2
T3
T4
T5
T6
CLK
BURST
TERMINATE
READ
NOP
NOP
NOP
NOP
NOP
COMMAND
ADDRESS
DQ
X = 1 cycle
BANK,
COL n
D
OUT
D
n + 1
OUT
DOUT
DOUT
n + 3
n
n + 2
CAS Latency = 2
T0
T1
T2
T3
T4
T5
T6
T7
CLK
COMMAND
ADDRESS
DQ
BURST
TERMINATE
READ
NOP
NOP
NOP
NOP
NOP
NOP
X = 2 cycles
BANK,
COL n
D
OUT
DOUT
D
n + 2
OUT
DOUT
n + 3
n
n + 1
CAS Latency = 3
NOTE:
DQM is LOW.
DON’T CARE
Figure 12
Terminating a READ Burst
128Mb: x4, x8, x16 SDRAM
128MSDRAM_E.p65 – Rev. E; Pub. 1/02
Micron Technology, Inc., reserves the right to change products or specifications without notice.
©2001, Micron Technology, Inc.
21
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