Internet Data Sheet
HYB25D512[40/16/80]0B[E/F/C/T](L)
Double-Data-Rate SDRAM
TABLE 14
Truth Table 4: Current State Bank n - Command to Bank m (different bank)
Current State
CS
RAS CAS WE Command
Action
Note
1)2)3)4)5)6)
Any
H
L
X
H
X
X
H
X
X
H
X
Deselect
NOP. Continue previous operation.
1) to 6)
No Operation
NOP. Continue previous operation.
–
1) to 6)
Idle
X
Any Command
Otherwise Allowed to
Bank m
1) to 6)
Row Activating,
Active, or Pre
charging
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
H
L
H
H
L
Active
Select and activate row
Select column and start Read burst
Select column and start Write burst
–
1) to 7)
H
H
L
Read
1) to 7)
L
Write
1) to 6)
H
H
L
L
Precharge
Active
1) to 6)
Read (Auto
Precharge
Disabled)
L
H
H
L
Select and activate row
Select column and start new Read burst
–
1) to 7)
H
L
Read
1) to 6)
H
H
L
Precharge
Active
1) to 6)
Write (Auto
Precharge
Disabled)
L
H
H
L
Select and activate row
Select column and start Read burst
Select column and start new Write burst
–
1) to 8)
H
H
L
Read
1) to 7)
L
Write
1) to 6)
H
H
L
L
Precharge
Active
1) to 6)
Read (With Auto
Precharge)
L
H
H
L
Select and activate row
Select column and start new Read burst
Select column and start Write burst
–
1) to 7), 9)
1) to 7), 9), 10)
1) to 6)
H
H
L
Read
L
Write
H
H
L
L
Precharge
Active
1) to 6)
Write (With Auto
Precharge)
L
H
H
L
Select and activate row
Select column and start Read burst
Select column and start new Write burst
–
1) to 7), 9)
1) to 7), 9)
1) to 6)
H
H
L
Read
L
Write
H
L
Precharge
1) This table applies when CKE n-1 was HIGH and CKE n is HIGH (see Table 12: Clock Enable (CKE) and after tXSNR/tXSRD has been met (if
the previous state was self refresh).
2) This table describes alternate bank operation, except where noted, i.e., the current state is for bank n and the commands shown are those
allowed to be issued to bank m (assuming that bank m is in such a state that the given command is allowable). Exceptions are covered in
the notes below.
3) Current state definitions:
Idle: The bank has been precharged, and tRP has been met.
Row Active: A row in the bank has been activated, and tRCD has been met. No data bursts/accesses and no register accesses are in
progress.
Read: A Read burst has been initiated, with Auto Precharge disabled, and has not yet terminated or been terminated.
Write: A Write burst has been initiated, with Auto Precharge disabled, and has not yet terminated or been terminated.
Read with Auto Precharge Enabled: See 10)
Write with Auto Precharge Enabled: See 10)
.
.
4) AUTO REFRESH and Mode Register Set commands may only be issued when all banks are idle.
5) A BURST TERMINATE command cannot be issued to another bank; it applies to the bank represented by the current state only.
6) All states and sequences not shown are illegal or reserved.
7) Reads or Writes listed in the Command/Action column include Reads or Writes with Auto Precharge enabled and Reads or Writes with
Auto Precharge disabled.
8) Requires appropriate DM masking.
Rev. 1.63, 2006-09
21
03062006-PFFJ-YJY2
QIMONDA [ QIMONDA AG ]
