mt47h128m16hg-3-it Micron Semiconductor Products, mt47h128m16hg-3-it Datasheet - Page 49

• Manufacturer Part Number: mt47h128m16hg-3-it
• Description: 2gb X4, X8, X16 Ddr2 Sdram
• Manufacturer: Micron Semiconductor Products

WRITE Command
Figure 32:
WRITE Operation
PDF: 09005aef824f87b6/Source: 09005aef824f1182
2gb_ddr2.fm - Rev. A 9/06 EN
WRITE Command
Note:
Note:
The WRITE command is used to initiate a burst write access to an active row. The value
on the BA2–BA0 inputs selects the bank, and the address provided on inputs A0–i (where
i = A9 for x8 and x16; or A9, A11 for x4) selects the starting column location. The value on
input A10 determines whether or not auto precharge is used. If auto precharge is
selected, the row being accessed will be precharged at the end of the WRITE burst; if
auto precharge is not selected, the row will remain open for subsequent accesses.
Input data appearing on the DQ is written to the memory array subject to the DM input
logic level appearing coincident with the data. If a given DM signal is registered LOW, the
corresponding data will be written to memory; if the DM signal is registered HIGH, the
corresponding data inputs will be ignored, and a WRITE will not be executed to that
byte/column location (Figure 42 on page 58).
WRITE bursts are initiated with a WRITE command, as shown in Figure 32. DDR2
SDRAM uses WL equal to RL minus one clock cycle [WL = RL - 1CK = AL + (CL - 1CK)].
The starting column and bank addresses are provided with the WRITE command, and
auto precharge is either enabled or disabled for that access. If auto precharge is enabled,
the row being accessed is precharged at the completion of the burst.
BANK ADDRESS
For the generic WRITE commands used in the following illustrations, auto precharge
is disabled.
CA = column address; BA = bank address; EN AP = enable auto precharge; and DIS AP = dis-
able auto precharge.
ADDRESS
CAS#
RAS#
WE#
A10
CKE
CK#
CS#
CK
HIGH
DON’T CARE
DIS AP
EN AP
BA
CA
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2Gb: x4, x8, x16 DDR2 SDRAM
©2006 Micron Technology, Inc. All rights reserved.
WRITE Command