128Mb: x4, x8, x16
SDRAM
TRUTH TABLE 2 – CKE
(Notes: 1-4)
CKEn-1 CKEn
CURRENT STATE
COMMANDn
ACTIONn
NOTES
L
L
L
H
L
Power-Down
Self Refresh
X
Maintain Power-Down
Maintain Self Refresh
Maintain Clock Suspend
Exit Power-Down
X
Clock Suspend
Power-Down
Self Refresh
X
COMMAND INHIBIT or NOP
COMMAND INHIBIT or NOP
X
5
6
7
Exit Self Refresh
Clock Suspend
All Banks Idle
All Banks Idle
Reading or Writing
Exit Clock Suspend
Power-Down Entry
Self Refresh Entry
H
COMMAND INHIBIT or NOP
AUTO REFRESH
VALID
Clock Suspend Entry
H
H
See Truth Table 3
NOTE: 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 ACTIONn 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 tCKS is met).
6. Exiting self refresh at clock edge n will put the device in the all banks idle state once tXSR is met. COMMAND INHIBIT
or NOP commands should be issued on any clock edges occurring during the tXSR period. A minimum of two NOP
commands must be provided during tXSR 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.
128Mb: x4, x8, x16 SDRAM
128MSDRAM_E.p65 – Rev. E; Pub. 1/02
Micron Technology, Inc., reserves the right to change products or specifications without notice.
©2001, Micron Technology, Inc.
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