IS42S32200B
TRUTH TABLE – CKE
(1-4)
CURRENT STATE
Power-Down
Self Refresh
Clock Suspend
Power-Down
Self Refresh
(5)
(6)
(7)
ISSI
COMMANDn
X
X
X
COMMAND INHIBIT or NOP
COMMAND INHIBIT or NOP
X
COMMAND INHIBIT or NOP
AUTO REFRESH
VALID
ACTIONn
Maintain Power-Down
Maintain Self Refresh
Maintain Clock Suspend
Exit Power-Down
Exit Self Refresh
Exit Clock Suspend
Power-Down Entry
Self Refresh Entry
Clock Suspend Entry
CKEn-1
L
L
L
L
L
L
H
H
H
H
CKEn
L
L
L
H
H
H
L
L
L
H
®
Clock Suspend
All Banks Idle
All Banks Idle
Reading or Writing
See TRUTH TABLE – CURRENT STATE BANK n, COMMAND TO BANK
n
NOTES:
1. CKEn is the logic state of CKE at clock edge
n;
CKEn-1 was the state of CKE at the previous clock edge.
2. Current state is the state of the SDRAM immediately prior to clock edge
n.
3. COMMANDn is the command registered at clock edge
n,
and ACTONn is a result of COMMANDn.
4. All states and sequences not shown are illegal or reserved.
5. Exiting power-down at clock edge
n
will put the device in the all banks idle state in time for clock edge
n+1
(provided that t
CKS
is met).
6. Exiting self refresh at clock edge
n
will put the device in all banks idle state once t
XSR
is met. COMMAND INHIBIT or NOP commands
should be issued on clock edges occurring during the t
XSR
period. A minimum of two NOP commands must be sent during t
XSR
period.
7. After exiting clock suspend at clock edge
n,
the device will resume operation and recognize the next command at clock edge
n+1.
TRUTH TABLE – CURRENT STATE BANK n, COMMAND TO BANK
n
(1-6)
CURRENT STATE
Any
Idle
COMMAND (ACTION)
COMMAND INHIBIT (NOP/Continue previous operation)
NO OPERATION (NOP/Continue previous operation)
ACTIVE (Select and activate row)
AUTO REFRESH
(7)
LOAD MODE REGISTER
(7)
PRECHARGE
(11)
Row Active
READ (Select column and start READ burst)
(10)
WRITE (Select column and start WRITE burst)
(10)
PRECHARGE (Deactivate row in bank or banks)
(8)
Read
(Auto
Precharge
Disabled)
Write
(Auto
Precharge
Disabled)
READ (Select column and start new READ burst)
(10)
WRITE (Select column and start WRITE burst)
(10)
PRECHARGE (Truncate READ burst, start PRECHARGE)
(8)
BURST TERMINATE
(9)
READ (Select column and start READ burst)
(10)
WRITE (Select column and start new WRITE burst)
(10)
PRECHARGE (Truncate WRITE burst, start PRECHARGE)
(8)
BURST TERMINATE
(9)
CS RAS CAS WE
H
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
X
H
L
L
L
L
H
H
L
H
H
L
H
H
H
L
H
X
H
H
L
L
H
L
L
H
L
L
H
H
L
L
H
H
X
H
H
H
L
L
H
L
L
H
L
L
L
H
L
L
L
7
Integrated Silicon Solution, Inc. — www.issi.com —
1-800-379-4774
Rev. 00C
09/29/03
ISSI [ INTEGRATED SILICON SOLUTION, INC ]
