is42s16402j Integrated Silicon Solution, Inc., is42s16402j Datasheet - Page 21

• Manufacturer Part Number: is42s16402j
• Description: 1 Meg Bits X 16 Bits X 4 Banks 64-mbit Synchronous Dynamic Ram
• Manufacturer: Integrated Silicon Solution, Inc.

IS42S16402J
IS45S16402J
Burst Length
Read and write accesses to the SDRAM are burst oriented,
with the burst length being programmable, as shown in
MODE REGISTER DEFINITION. The burst length deter-
mines the maximum number of column locations 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 type. The full-page
burst is used in conjunction with the BURST TERMINATE
command to generate arbitrary burst lengths.
Reserved states should not be used, as unknown operation
or incompatibility with future versions may result.
When a READ or WRITE command is issued, a block of
columns equal to the burst length is effectively selected. All
accesses for that burst take place within this block, mean-
Page
Integrated Silicon Solution, Inc. — www.issi.com
Rev. A
12/06/2011
BURST DEFINITION
Length
Burst
Full
(y)
2
4
8
(location 0-y)
n = A0-A7
A2
0
0
0
0
1
1
1
1
Starting Column
Address
A1
A1
1
0
0
1
1
0
0
1
0
0
1
1
A0
A0
A0
0
0
1
0
1
0
1
0
1
1
0
1
0
1
Type = Sequential
Cn, Cn + 1, Cn + 2
Cn + 3, Cn + 4...
2-3-4-5-6-7-0-1
3-4-5-6-7-0-1-2
0-1-2-3-4-5-6-7
1-2-3-4-5-6-7-0
4-5-6-7-0-1-2-3
5-6-7-0-1-2-3-4
6-7-0-1-2-3-4-5
7-0-1-2-3-4-5-6
…Cn - 1,
0-1-2-3
1-2-3-0
2-3-0-1
3-0-1-2
Cn…
0-1
1-0
Burst Type
Accesses within a given burst may be programmed to be
either sequential or interleaved; this is referred to as the
burst type and is selected via bit M3.
The ordering of accesses within a burst is determined by
ing that the burst will wrap within the block if a boundary
is reached. The block is uniquely selected by A1-A7 (x16)
when the burst length is set to two; by A2-A7 (x16) when
the burst length is set to four; and by A3-A7 (x16) when the
burst length is set to eight. 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.
the burst length, the burst type and the starting column
address, as shown in BURST DEFINITION table.
Order of Accesses Within a Burst
Type = Interleaved
1-0-3-2-5-4-7-6
0-1-2-3-4-5-6-7
2-3-0-1-6-7-4-5
3-2-1-0-7-6-5-4
4-5-6-7-0-1-2-3
5-4-7-6-1-0-3-2
6-7-4-5-2-3-0-1
7-6-5-4-3-2-1-0
Not Supported
0-1-2-3
1-0-3-2
2-3-0-1
3-2-1-0
0-1
1-0
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