Read
HYB25D128[400/800/160]C[C/E/T](L)
128 Mbit Double Data Rate SDRAM
Functional Description
Data Sheet
56
Rev. 1.0, 2004-04
Table 10
Current State
Any
Truth Table 4: Current State Bank n - Command to Bank m (different bank)
CS
RAS CAS WE
Command
H
X
X
X
Deselect
L
H
H
H
No Operation
X
X
X
X
Any Command
Otherwise Allowed
to Bank m
Row Activating,
Active, or
Precharging
L
H
L
L
Write
L
L
H
L
Precharge
Read (Auto
Precharge
Disabled)
Action
NOP. Continue previous operation.
NOP. Continue previous operation.
–
Notes
1)2)3)4)5)6)
1) to 6)
Idle
1) to 6)
L
L
L
H
H
L
H
H
Active
Read
Select and activate row
Select column and start Read burst
Select column and start Write burst
–
Select and activate row
Select column and start new Read
burst
–
Select and activate row
Select column and start Read burst
Select column and start new Write
burst
–
Select and activate row
Select column and start new Read
burst
Select column and start Write burst
–
Select and activate row
Select column and start Read burst
Select column and start new Write
burst
–
1) to 6)
1) to 7)
1) to 7)
1) to 6)
L
L
L
H
H
L
H
H
Active
Read
1) to 6)
1) to 7)
L
L
L
L
L
L
H
H
H
H
L
L
L
H
H
L
Precharge
Active
Read
Write
1) to 6)
Write (Auto
Precharge
Disabled)
1) to 6)
1) to 8)
1) to 7)
L
L
L
L
L
H
H
H
L
L
H
H
Precharge
Active
1) to 6)
Read (With Auto
Precharge)
1) to 6)
1) to 7), 9)
L
L
L
L
L
H
L
L
H
H
L
H
H
L
L
L
L
H
H
L
Write
Precharge
Active
Read
Write
1) to 7), 9), 10)
1) to 6)
Write (With Auto
Precharge)
1) to 6)
1) to 7), 9)
1) to 7), 9)
L
L
H
L
Precharge
1) to 6)
1) This table applies when CKE n-1 was HIGH and CKE n is HIGH (see
Table 8
: Clock Enable (CKE) and after
t
XSNR
/
t
XSRD
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
t
RP
has been met.
Row Active: A row in the bank has been activated, and
t
RCD
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.