mt46h16m16lf Micron Semiconductor Products, mt46h16m16lf Datasheet - Page 23

• Manufacturer Part Number: mt46h16m16lf
• Description: 256mb X16, X32 Mobile Ddr Sdram
• Manufacturer: Micron Semiconductor Products

DESELECT
NO OPERATION (NOP)
LOAD MODE REGISTER
ACTIVE
READ
WRITE
PDF: 09005aef82091978 / Source: 09005aef8209195b
MT46H16M16LF__2.fm - Rev. H 3/08 EN
The DESELECT function (CS# HIGH) prevents new commands from being executed by
the Mobile DDR SDRAM. Operations already in progress are not affected.
The NO OPERATION (NOP) command is used to instruct the selected Mobile DDR
SDRAM to perform a NOP (CS# is LOW with RAS#, CAS#, and WE# HIGH). This prevents
unwanted commands from being registered during idle or wait states. Operations
already in progress are not affected.
The mode registers are loaded via inputs BA0–BA1 and A0–A12. See mode register
descriptions in “Register Definition” on page 15. The LOAD MODE REGISTER command
can only be issued when all banks are idle, and a subsequent executable command
cannot be issued until
The ACTIVE command is used to open (or activate) a row in a particular bank for a
subsequent access. The value on the BA0 and BA1 inputs selects the bank, and the
address provided on inputs A0–A12 selects the row. This row remains active (or open) for
accesses until a PRECHARGE command is issued to that bank. A PRECHARGE
command must be issued before opening a different row in the same bank.
The READ command is used to initiate a burst read access to an active row. The value on
the BA0, BA1 inputs selects the bank, and the address provided on inputs A0–Ai (where i
= the most significant column address bit for each configuration) selects the starting
column location. The value on input A10 determines whether auto precharge is used. If
auto precharge is selected, the row being accessed will be precharged at the end of the
READ burst; if auto precharge is not selected, the row will remain open for subsequent
accesses.
The WRITE command is used to initiate a burst write access to an active row. The value
on the BA0–BA1 inputs selects the bank, and the address provided on inputs A0–Ai
(where i = the most significant column address bit for each configuration) selects the
starting column location. The value on input A10 determines whether 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 subse-
quent 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.
t
MRD is met.
23
Micron Technology, Inc., reserves the right to change products or specifications without notice.
256Mb: x16, x32 Mobile DDR SDRAM
©2005 Micron Technology, Inc. All rights reserved.
Commands