IS42S83200B, IS42S16160B
BURST LENGTH
ReadandwriteaccessestotheSDRAMareburstoriented,
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
burstisavailableforthesequentialtype.Thefull-pageburst
is used in conjunction with the BURST TERMINATE com-
mand to generate arbitrary burst lengths.
ing that the burst will wrap within the block if a boundary is
reached. The block is uniquely selected by A1-A8 (x16) or
A1-A9 (x8) when the burst length is set to two; by A2-A8
(x16)orA2-A9(x8)whentheburstlengthissettofour;and
byA3-A8(x16)orA3-A9(x8)whentheburstlengthissetto
eight.Theremaining(leastsignificant)addressbit(s)is(are)
used to select the starting location within the block. Full-
pageburstswrapwithinthepageiftheboundaryisreached.
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.
Reservedstatesshouldnotbeused,asunknownoperation
or incompatibility with future versions may result.
When a READ or WRITE command is issued, a block of
columnsequaltotheburstlengthiseffectivelyselected.All
accesses for that burst take place within this block, mean-
Theorderingofaccesseswithinaburstisdeterminedbythe
burstlength,thebursttypeandthestartingcolumnaddress,
as shown in BURST DEFINITION table.
BURST DEFINITION
Burst
StartingColumn
Address
OrderofAccessesWithinaBurst
Length
Type=Sequential
Type=Interleaved
A 0
2
4
0
1
0-1
1-0
0-1
1-0
A 1
0
A 0
0
0-1-2-3
1-2-3-0
2-3-0-1
3-0-1-2
0-1-2-3
1-0-3-2
2-3-0-1
3-2-1-0
0
1
1
0
1
1
A 2
0
A 1
0
A 0
0
0-1-2-3-4-5-6-7
1-2-3-4-5-6-7-0
2-3-4-5-6-7-0-1
3-4-5-6-7-0-1-2
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
0-1-2-3-4-5-6-7
1-0-3-2-5-4-7-6
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
NotSupported
0
0
1
0
1
0
8
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Full
Page
(y)
n = A0-A8(x16)
n = A0-A9(x8)
(location0-y)
Cn,Cn+1,Cn+2
Cn+3,Cn+4...
…Cn-1,
Cn…
Integrated Silicon Solution, Inc. — www.issi.com
25
Rev. D
07/28/08
ISSI [ INTEGRATED SILICON SOLUTION, INC ]
