hm5264165f-75 Elpida Memory, Inc., hm5264165f-75 Datasheet - Page 12

• Manufacturer Part Number: hm5264165f-75
• Description: 64m Lvttl Interface Sdram
• Manufacturer: Elpida Memory, Inc.

HM5264165F/HM5264805F/HM5264405F-75/A60/B60
DQM Truth Table (HM5264165F)
Command
Upper byte write enable/output enable
Lower byte write enable/output enable
Upper byte write inhibit/output disable
Lower byte write inhibit/output disable
Note: H: V
DQM Truth Table (HM5264805F/HM5264405F)
Command
Write enable/output enable
Write inhibit/output disable
Note: H: V
The SDRAM can mask input/output data by means of DQM, DQMU/DQML.
DQMU masks the upper byte and DQML masks the lower byte. (HM5264165F)
During reading, the output buffer is set to Low-Z by setting DQM, DQMU/DQML to Low, enabling data
output. On the other hand, when DQM, DQMU/DQML is set to High, the output buffer becomes High-Z,
disabling data output.
During writing, data is written by setting DQM, DQMU/DQML to Low. When DQM, DQMU/DQML is set
to High, the previous data is held (the new data is not written). Desired data can be masked during burst read
or burst write by setting DQMU/DQML. For details, refer to the DQM, DQMU/DQML control section of the
SDRAM operating instructions.
12
Write: I
Read: I
Write: I
Read: I
IH
IH
. L: V
. L: V
DID
DID
DOD
DOD
is needed.
is needed.
is needed.
is needed.
IL
IL
. : V
. : V
IH
IH
or V
or V
IL
IL
.
.
Data Sheet E0135H10
Symbol
ENBU
ENBL
MASKU
MASKL
Symbol
ENB
MASK
CKE
n - 1
H
H
H
H
CKE
n - 1
H
H
n
n
DQMU
L
H
DQM
L
H
DQML
L
H