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128Mbx16x32Mobile_2.fm - Rev. M 1/09 EN
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2001 Micron Technology, Inc. All rights reserved.
128Mb: x16, x32 Mobile SDRAM
Register Definition
The mode register must be loaded when all banks are idle, and the controller must wait
the specified time before initiating the subsequent operation. Violating either of these
requirements will result in unspecified operation.
Burst Length (BL)
Read and write accesses to the SDRAM are burst oriented, with BL being programmable,
tions that can be accessed for a given READ or WRITE command. Burst lengths of 1, 2, 4,
or 8 locations are available for both the sequential and the interleaved burst types, and a
full-page burst is available for the sequential mode. The full-page burst is used in
conjunction with the BURST TERMINATE command to generate arbitrary burst lengths.
If a full page burst is not terminated at the end of the page, it could wrap to column zero
and continue.
Reserved states cannot be used because unknown operation or incompatibility with
future versions may result.
When a READ or WRITE command is issued, a block of columns equal to BL is effectively
selected. All accesses for that burst take place within this block, meaning that the burst
will wrap within the block if a boundary is reached. The block is uniquely selected by A1–
A8 (x16) or A1–A7 (x32) when BL = 2; by A2–A8 (x16) or A2–A7 (x32) when BL = 4; and by
A3–A8 (x16) or A3–A7 (x32) when BL = 8. The remaining (least significant) address bit(s)
is (are) used to select the starting location within the block. Full-page bursts wrap within
the page if the boundary is reached.
Burst Type
Accesses within a given burst may be programmed either to be sequential or interleaved;
this is referred to as the burst type and is selected via bit M3. Note only a sequential burst
is allowed for full page bursts.
The ordering of accesses within a burst is determined by BL, the burst type, and the