WED9LC6816V
White Electronic Designs
SDRAM CURRENT STATE TRUTH TABLE
Command
Current State
Action
Notes
1
SDCE#
SDRAS #
SDCAS#
SDWE#
A12 & A13 (BA)
A11-A0
Description
Set the Mode Register
Auto or Self Refresh
Precharge
L
L
L
L
L
L
L
L
L
L
L
L
L
H
L
OP Code
Mode Register Set
1
Start Auto
X
X
X
L
H
H
L
X
Row Address
Column
Column
X
No Operation
L
H
L
BA
BA
BA
X
Bank Activate
Activate the specified bank and row
ILLEGAL
H
H
H
H
Write w/o Precharge
Read w/o Precharge
Burst Termination
No Operation
2
1
1
Idle
L
H
L
ILLEGAL
H
H
No Operation
H
X
X
No Operation
H
X
X
X
X
X
Device Deselect
No Operation
L
L
L
L
L
L
L
L
L
L
L
H
L
OP Code
Mode Register Set
Auto or Self Refresh
Precharge
ILLEGAL
ILLEGAL
Precharge
ILLEGA
X
X
H
H
X
X
3
1
H
BA
Row Address
Bank Activate
L
H
L
L
BA
Column
Write
Start Write; Determine if Auto Precharge
4,5
4,5
Row Active
L
L
L
H
H
H
L
H
H
H
L
BA
X
Column
Read
Start Read; Determine if Auto Precharge
No Operation
X
X
Burst Termination
No Operation
H
X
No Operation
H
X
X
X
X
X
Device Deselect
No Operation
L
L
L
L
L
L
L
L
H
L
L
L
L
L
H
L
OP Code
OP Code
OP Code
Mode Register Set
Auto or Self Refresh
Precharge
ILLEGAL
ILLEGAL
X
X
X
L
H
H
L
X
Terminate Burst; Start the Precharge
ILLEGAL
L
H
L
BA
BA
BA
X
Row Address
Bank Activate
Write
2
Read
H
H
H
H
X
Column
Terminate Burst; Start the Write cycle
Terminate Burst; Start a new Read cycle
Terminate the Burst
5,6
5,6
L
H
L
Column
Read
H
H
X
X
X
X
Burst Termination
No Operation
Device Deselect
H
X
X
Continue the Burst
X
Continue the Burst
L
L
L
L
Mode Register Set
ILLEGAL
L
L
L
L
L
L
L
H
L
L
L
L
L
L
L
L
L
L
L
H
H
L
H
L
X
X
X
Auto or Self Refresh
Precharge
ILLEGAL
Terminate Burst; Start the Precharge
ILLEGAL
X
L
H
L
BA
BA
BA
X
Row Address
Bank Activate
Write
2
Write
H
H
H
H
X
L
Column
Terminate Burst; Start a new Write cycle
Terminate Burst; Start the Read cycle
Terminate the Burst
Continue the Burst
Continue the Burst
ILLEGAL
5,6
5,6
L
H
L
Column
Read
H
H
X
L
X
X
X
Burst Termination
No Operation
Device Deselect
Mode Register Set
Auto or Self Refresh
Precharge
H
X
L
X
X
L
L
H
L
X
X
X
ILLEGAL
L
H
H
L
X
Row Address
Column
Column
X
ILLEGAL
2
2
L
H
L
BA
BA
BA
X
Bank Activate
Write
ILLEGAL
Read with
Auto Precharge
H
H
H
H
ILLEGAL
L
H
L
Read
ILLEGAL
H
H
Burst Termination
No Operation
ILLEGAL
H
X
X
Continue the Burst
H
X
X
X
X
X
Device Deselect
Continue the Burst
Contact factory for ordering information.
White Electronic Designs Corp. reserves the right to change products or specifications without notice.
September, 2003
Rev. 1
11
White Electronic Designs Corporation • (602) 437-1520 • www.wedc.com