64Mb: x32
SDRAM
CLOCK SUSPEND
The clock suspend mode occurs when a column ac-
cess/burst is in progress and CKE is registered LOW. In
the clock suspend mode, the internal clock is deacti-
vated, “freezing” the synchronous logic.
Clock suspend mode is exited by registering CKE
HIGH; the internal clock and related operation will re-
sume on the subsequent positive clock edge.
For each positive clock edge on which CKE is
sampled LOW, the next internal positive clock edge is
suspended. Any command or data present on the in-
put pins at the time of a suspended internal clock edge
is ignored; any data present on the DQ pins remains
driven; and burst counters are not incremented, as
long as the clock is suspended. (See examples in Fig-
ures 22 and 23.)
BURST READ/SINGLE WRITE
The burst read/single write mode is entered by pro-
gramming the write burst mode bit (M9) in the Mode
Register to a logic 1. In this mode, all WRITE commands
result in the access of a single column location (burst of
one), regardless of the programmed burst length. READ
commands access columns according to the pro-
grammed burst length and sequence, just as in the
normal mode of operation (M9 = 0).
Figure 22
Figure 23
CLOCK SUSPEND During WRITE Burst
CLOCK SUSPEND During READ Burst
T0
T1
T2
T3
T4
T5
T6
T0
T1
T2
T3
T4
T5
CLK
CKE
CLK
CKE
INTERNAL
CLOCK
INTERNAL
CLOCK
READ
NOP
NOP
NOP
NOP
NOP
COMMAND
ADDRESS
DQ
NOP
WRITE
NOP
NOP
COMMAND
ADDRESS
BANK,
COL n
BANK,
COL n
D
OUT
D
OUT
D
n + 2
OUT
DOUT
n + 3
n
n + 1
D
n
IN
D
n + 1
IN
DIN
n + 2
D
IN
DON’T CARE
NOTE: For this example, CAS latency = 2, burst length = 4 or greater, and
DQM is LOW.
DON’T CARE
64Mb: x32 SDRAM
64MSDRAMx32_5.p65 – Rev. B; Pub. 6/02
MicronTechnology,Inc.,reservestherighttochangeproductsorspecificationswithoutnotice.
©2002,MicronTechnology,Inc.
22
MICRON [ MICRON TECHNOLOGY ]
