IBMN325164CT3
IBMN325804CT3
IBMN325404CT3
Preliminary
256Mb Synchronous DRAM - Die Revision B
Current State Truth Table (Part 3 of 3)(See note 1)
Command
Current State
Action
Notes
CS RAS CAS WE BA0,BA1
A12 - A0
Description
L
L
L
L
L
L
L
H
L
L
L
L
L
L
L
H
L
L
L
L
L
L
L
H
L
L
L
L
L
L
L
H
L
L
L
L
L
H
L
OP Code
Mode Register Set
ILLEGAL
X
BS
BS
BS
BS
X
X
X
Auto or Self Refresh ILLEGAL
L
H
H
L
Precharge
ILLEGAL
ILLEGAL
4
4
9
9
L
H
L
Row Address Bank Activate
Write
Recovering
H
H
H
X
L
Column
Write
Start Write; Determine if Auto Precharge
Start Read; Determine if Auto Precharge
L
H
H
X
L
Column
Read
H
X
L
X
X
No Operation
Device Deselect
Mode Register Set
No Operation; Row Active after t
No Operation; Row Active after t
ILLEGAL
DPL
DPL
X
OP Code
L
L
H
L
X
BS
BS
BS
BS
X
X
X
Auto or Self Refresh ILLEGAL
Write
Recovering
with
Auto Pre-
charge
L
H
H
L
Precharge
ILLEGAL
4
L
H
L
Row Address Bank Activate
ILLEGAL
4
H
H
H
X
L
Column
Write
ILLEGAL
4, 9
4, 9
L
H
H
X
L
Column
Read
ILLEGAL
H
X
L
X
X
No Operation
Device Deselect
Mode Register Set
No Operation; Precharge after t
No Operation; Precharge after t
ILLEGAL
DPL
DPL
X
OP Code
L
L
H
L
X
BS
BS
BS
BS
X
X
X
Auto or Self Refresh ILLEGAL
L
H
H
L
Precharge
ILLEGAL
L
H
L
Row Address Bank Activate
ILLEGAL
Refreshing
H
H
H
X
L
Column
Write
ILLEGAL
L
H
H
X
L
Column
Read
ILLEGAL
H
X
L
X
X
No Operation
Device Deselect
Mode Register Set
No Operation; Idle after t
No Operation; Idle after t
ILLEGAL
RC
RC
X
OP Code
L
L
H
L
X
BS
BS
BS
BS
X
X
X
Auto or Self Refresh ILLEGAL
L
H
H
L
Precharge
ILLEGAL
ILLEGAL
ILLEGAL
ILLEGAL
Mode
Register
Accessing
L
H
L
Row Address Bank Activate
H
H
H
X
Column
Write
L
H
H
X
Column
Read
H
X
X
X
No Operation
Device Deselect
No Operation; Idle after two clock cycles
No Operation; Idle after two clock cycles
X
1. CKE is assumed to be active (high) in the previous cycle for all entries. The Current State is the state of the bank that the Com-
mand is being applied to.
2. All Banks must be idle; otherwise, it is an illegal action.
3. If CKE is active (high) the SDRAM will start the Auto (CBR) Refresh operation, if CKE is inactive (low) than the Self Refresh mode
is entered.
4. The Current State refers to only one of the banks. If BS selects this bank then the action is illegal. If BS selects the bank not being
referenced by the Current State then the action may be legal depending on the state of that bank.
5. If CKE is inactive (low) then the Power Down mode is entered; otherwise there is a No Operation.
6. The minimum and maximum Active time (t
) must be satisfied.
RAS
7. The RAS to CAS Delay (t
) must occur before the command is given.
RCD
8. Column address A10 is used to determine if the Auto Precharge function is activated.
9. The command must satisfy any bus contention, bus turn around, and/or write recovery requirements.
10. The command is illegal if the minimum bank to bank delay time (t
) is not satisfied.
RRD
©IBM Corporation. All rights reserved.
Use is further subject to the provisions at the end of this document.
06K0608.F39375A
10/00
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