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64MSDRAM_2.fm - Rev. N 12/08 EN
37
2000 Micron Technology, Inc. All rights reserved.
64Mb: x4, x8, x16 SDRAM
Commands
READ with Auto Precharge
Interrupted by a READ (with or without auto precharge): A READ to bank m will inter-
rupt a READ on bank n, CL later. The precharge to bank n will begin when the READ
Interrupted by a WRITE (with or without auto precharge): A WRITE to bank m will
interrupt a READ on bank n when registered. DQM should be used two clocks prior to
the WRITE command to prevent bus contention. The precharge to bank n will begin
WRITE with Auto Precharge
Interrupted by a READ (with or without auto precharge): A READ to bank m will inter-
rupt a WRITE on bank n when registered, with the data-out appearing CL later. The
precharge to bank n will begin after tWR is met, where tWR begins when the READ to
bank m is registered. The last valid WRITE to bank n will be data-in registered one
Interrupted by a WRITE (with or without auto precharge): A WRITE to bank m will
interrupt a WRITE on bank n when registered. The precharge to bank n will begin
after tWR is met, where tWR begins when the WRITE to bank m is registered. The last
valid data WRITE to bank n will be data registered one clock prior to a WRITE to bank
Figure 29:
READ With Auto Precharge Interrupted by a READ
Note:
DQM is LOW.
DON’T CARE
CLK
DQ
DOUT
a
T2
T1
T4
T3
T6
T5
T0
COMMAND
READ - AP
BANK n
NOP
DOUT
a + 1
DOUT
d
DOUT
d + 1
NOP
T7
BANK n
CAS Latency = 3 (BANK m)
BANK m
ADDRESS
Idle
NOP
BANK n,
COL a
BANK m,
COL d
READ - AP
BANK m
Internal
States
t
Page Active
READ with Burst of 4
Interrupt Burst, Precharge
Page Active
READ with Burst of 4
Precharge
RP - BANK n
tRP - BANK m
CAS Latency = 3 (BANK n)
TRANSITIONING DATA