WED3DL644V8BC 데이터 시트보기 (PDF) - White Electronic Designs Corporation
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WED3DL644V8BC Datasheet PDF : 28 Pages
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White Electronic Designs
WED3DL644V
CURRENT STATE TRUTH TABLE (CONT.)
Command
Current State
CE#
RAS#
CAS#
WE#
BA0-1
A11,
A10/AP-A0
Description
Action
Notes
L
L
L
L
OP Code
Mode Register Set
ILLEGAL
L
L
L
H
X
X
Auto or Self Refresh
ILLEGAL
L
L
H
L
X
X
Precharge
ILLEGAL
L
L
H
H
BA Row Address
Bank Activate
ILLEGAL
Refreshing
L
H
L
L
BA
Column
Write
ILLEGAL
L
H
L
H
BA
Column
Read
ILLEGAL
L
H
H
L
X
X
Burst Termination
No Operation; Idle after trc
L
H
H
H
X
X
No Operation
No Operation; Idle after trc
H
X
X
X
X
X
Device Deselect
No Operation; Idle after trc
L
L
L
L
OP Code
Mode Register Set
Load mode register
L
L
L
H
X
X
Auto or Self Refresh
ILLEGAL
L
L
H
L
X
X
Precharge
ILLEGAL
L
L
H
H
BA Row Address
Bank Activate
Mode Register
Accessing
L
H
L
L
BA
Column
Write
L
H
L
H
BA
Column
Read
ILLEGAL
ILLEGAL
ILLEGAL
L
H
H
L
X
X
Burst Termination
ILLEGAL
L
H
H
H
X
X
No Operation
No Operation; Idle after two clock cycles
H
X
X
X
X
X
Device Deselect No Operation; Idle after two clock cycles
Notes:
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 command is being applied to.
2. Both Banks must be idle otherwise it is an illegal action.
3. If CKE is active (high) the SDRAM starts the Auto (CBR) Refresh operation, if CKE is inactive (low) then the Self Refresh mode is entered.
4. The Current State refers only refers to one of the banks, if BA selects this bank then the action is illegal. If BA 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) than the Power Down mode is entered, otherwise there is a No Operation.
6. The minimum and maximum Active time (tRAS) must be satisfied.
7. The RAS# to CAS# Delay (tRCD) must occur before the command is given.
8. 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.
August 2005
Rev. 6
11
White Electronic Designs Corporation • (602) 437-1520 • www.wedc.com
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