Internet Data Sheet
HY[B/I]25DC512[80/16]0D[E/F](L)
512-Mbit Double-Data-Rate SDRAM
4
Truth Tables
The truth tables in this chapter summarize the commands and there signal coding to control a standard Double-Data-Rate
SDRAM.
TABLE 12
Truth Table 1: Commands
Name (Function)
CS RAS CAS WE Address
MNE
Note
1)2)
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)2)
1)3)
1)4)
1)4)
1)5)
1)6)
1)7)8)
1)9)
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
H
H
H
L
Bank/Col
Bank/Col
X
Read
Write
BST
L
H
H
L
L
Precharge (Deactivate Row In Bank Or Banks)
Auto Refresh Or Self Refresh (Enter Self Refresh Mode)
Mode Register Set
L
Code
PRE
L
H
L
X
AR/SR
MRS
L
L
Op-Code
1) CKE is HIGH for all commands shown exceptSelf Refresh.VREF must be maintained during Self Refresh operation.
2) Deselect and NOP are functionally interchangeable.
3) BA0, BA1 provide bank address and A0 - Ai provide row address.
4) BA0, BA1 provide bank address; A0 - Ai provide column address; 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 - Ai provide the op-code to be written to the selected Mode
Register.
TABLE 13
Truth Table 2: DM Operation
Name (Function)
DM
DQs
Note
1)
Write Enable
L
Valid
X
Write Inhibit
H
1) Used to mask write data; provided coincident with the corresponding data.
Rev. 1.10, 2008-05
18
06212007-08MW-K87L
QIMONDA [ QIMONDA AG ]
