HYB25D256[400/800/160]B[T/C](L)
256-Mbit Double Data Rate SDRAM
Functional Description
Table 6
Truth Table 1a: Commands
Name (Function)
CS RAS CAS WE Address MNE
Notes
1)9)
Deselect (NOP)
H
L
L
L
L
L
L
L
L
X
H
L
X
H
H
L
X
H
H
H
L
X
X
NOP
NOP
1)9)2)
1)3)
No Operation (NOP)
Active (Select Bank And Activate Row)
Read (Select Bank And Column, And Start Read Burst)
Write (Select Bank And Column, And Start Write Burst)
Burst Terminate
Bank/Row ACT
Bank/Col Read
Bank/Col Write
1)4)
H
H
H
L
1)4)5)
1)8)6)
1)5)7)
1)6)7)8)
1)2)9)
L
H
H
L
L
X
BST
Precharge (Deactivate Row In Bank Or Banks)
Auto Refresh Or Self Refresh (Enter Self Refresh Mode)
Mode Register Set
L
Code
X
PRE
L
H
L
AR/ SR
L
L
Op-Code MRS
1) CKE is HIGH for all commands shown except Self Refresh.
2) Deselect and NOP are functionally interchangeable.
3) BA0-BA1 provide bank address and A0-A12 provide row address.
4) BA0, BA1 provide bank address; A0-Ai provide column address (where i = 8 for x16, i = 9 for x8 and 9, 11 for x4); A10
HIGH enables the Auto Precharge feature (nonpersistent), A10 LOW disables the Auto Precharge feature.
5) Applies only to read bursts with Auto Precharge disabled; this command is undefined (and should not be used) for read
bursts with Auto Precharge enabled or for write bursts.
6) A10 LOW: BA0, BA1 determine which bank is precharged. A10 HIGH: all banks are precharged and BA0, BA1 are “Don’t
Care”.
7) This command is AUTO REFRESH if CKE is HIGH; Self Refresh if CKE is LOW.
8) Internal refresh counter controls row and bank addressing; all inputs and I/Os are “Don’t Care” except for CKE.
9) BA0, BA1 select either the Base or the Extended Mode Register (BA0 = 0, BA1 = 0 selects Mode Register; BA0 = 1, BA1
= 0 selects Extended Mode Register; other combinations of BA0-BA1 are reserved; A0-A12 provide the op-code to be
written to the selected Mode Register).
Table 7
Truth Table 1b: DM Operation
Name (Function)
Write Enable
DM
L
DQs
Valid
X
Notes
1)
1)
Write Inhibit
H
1) Used to mask write data; provided coincident with the corresponding data.
Data Sheet
23
Rev. 1.21, 2004-07
02102004-TSR1-4ZWW
QIMONDA [ QIMONDA AG ]
