IBMN325164CT3
IBMN325404CT3
IBMN325804CT3
256Mb Synchronous DRAM - Die Revision B
Preliminary
Clock Enable (CKE) Truth Table
CKE
Command
WE
Current State
Action
Notes
1
Previous Current
BA0,
BA1
CS
RAS CAS
A12 - A0
Cycle
H
L
Cycle
X
X
H
L
X
X
H
H
H
L
X
X
H
H
L
X
X
H
L
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
INVALID
H
H
H
H
H
L
Exit Self Refresh with Device Deselect
Exit Self Refresh with No Operation
ILLEGAL
2
2
2
2
2
L
Self Refresh
L
L
L
L
X
X
X
X
X
X
X
X
X
X
H
L
ILLEGAL
L
L
X
X
X
X
X
X
X
X
H
L
ILLEGAL
L
X
X
H
L
X
X
X
X
X
X
H
L
Maintain Self Refresh
INVALID
H
L
X
1
2
2
H
H
L
Power Down mode exit, all banks idle
ILLEGAL
Power Down
L
L
X
H
L
Maintain Power Down Mode
H
H
H
H
H
H
H
H
H
H
L
H
H
H
H
H
L
3
3
3
Refer to the Idle State section of the
Current State Truth Table
L
L
L
X
X
CBR Refresh
L
L
L
OP Code
Mode Register Set
4
3
3
3
4
All Banks Idle
H
L
X
H
L
X
X
H
L
X
X
X
H
L
Refer to the Idle State section of the
Current State Truth Table
L
L
L
L
L
L
X
X
Entry Self Refresh
Mode Register Set
Power Down
L
L
L
L
OP Code
X
X
X
X
X
X
X
X
X
4
5
Refer to operations in the Current
State Truth Table
H
H
X
X
X
X
Any State
other than
listed above
H
L
L
L
H
L
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Begin Clock Suspend next cycle
Exit Clock Suspend next cycle
Maintain Clock Suspend
1. For the given Current State CKE must be low in the previous cycle.
2. When CKE has a low to high transition, the clock and other inputs are re-enabled asynchronously. The minimum setup time for
CKE (t ) must be satisfied. When exiting power down mode, a NOP command (or Device Deselect Command) is required on
CES
the first rising clock after CKE goes high (see page 26).
3. The address inputs depend on the command that is issued. See the Idle State section of the Current State Truth Table for more
information.
4. The Precharge Power Down Mode, the Self Refresh Mode, and the Mode Register Set can only be entered from the all banks idle
state.
5. Must be a legal command as defined in the Current State Truth Table.
©IBM Corporation. All rights reserved.
Use is further subject to the provisions at the end of this document.
06K0608.F39375A
10/00
Page 30 of 66
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