IS42S16400F
IC42S16400F
Burst Length
ing that the burst will wrap within the block if a boundary
isꢀreached.ꢀTheꢀblockꢀisꢀuniquelyꢀselectedꢀbyꢀA1-A7ꢀ(x16)ꢀ
whenꢀtheꢀburstꢀlengthꢀisꢀsetꢀtoꢀtwo;ꢀbyꢀA2-A7ꢀ(x16)ꢀwhenꢀ
theꢀburstꢀlengthꢀisꢀsetꢀtoꢀfour;ꢀandꢀbyꢀA3-A7ꢀ(x16)ꢀwhenꢀtheꢀ
burstꢀlengthꢀisꢀsetꢀtoꢀeight.ꢀTheꢀremainingꢀ(leastꢀsignificant)ꢀ
address bit(s) is (are) used to select the starting location
withinꢀtheꢀblock.ꢀFull-pageꢀburstsꢀwrapꢀwithinꢀtheꢀpageꢀifꢀ
the boundary is reached.
ReadꢀandꢀwriteꢀaccessesꢀtoꢀtheꢀSDRAMꢀareꢀburstꢀoriented,ꢀ
with the burst length being programmable, as shown in
MODEꢀREGISTERꢀDEFINITION.ꢀTheꢀburstꢀlengthꢀdeter-
minesꢀtheꢀmaximumꢀnumberꢀofꢀcolumnꢀlocationsꢀthatꢀcanꢀ
beꢀaccessedꢀforꢀaꢀgivenꢀREADꢀorꢀWRITEꢀcommand.ꢀBurstꢀ
lengths of 1, 2, 4 or 8 locations are available for both the
sequential and the interleaved burst types, and a full-page
burstꢀisꢀavailableꢀforꢀtheꢀsequentialꢀtype.ꢀTheꢀfull-pageꢀ
burstꢀisꢀusedꢀinꢀconjunctionꢀwithꢀtheꢀBURSTꢀTERMINATEꢀ
command to generate arbitrary burst lengths.
Burst Type
Accesses within a given burst may be programmed to be
eitherꢀsequentialꢀorꢀinterleaved;ꢀthisꢀisꢀreferredꢀtoꢀasꢀtheꢀ
burst type and is selected via bit M3.
Reservedꢀstatesꢀshouldꢀnotꢀbeꢀused,ꢀasꢀunknownꢀoperationꢀ
or incompatibility with future versions may result.
WhenꢀaꢀREADꢀorꢀWRITEꢀcommandꢀisꢀissued,ꢀaꢀblockꢀofꢀ
columnsequaltotheburstlengthiseffectivelyselected.All
accesses for that burst take place within this block, mean-
Theꢀorderingꢀofꢀaccessesꢀwithinꢀaꢀburstꢀisꢀdeterminedꢀbyꢀ
the burst length, the burst type and the starting column
address,ꢀasꢀshownꢀinꢀBURSTꢀDEFINITIONꢀtable.
BURST DEFINITION
Burst
Starting Column
Address
Order of Accesses Within a Burst
Length
Type = Sequential
Type = Interleaved
A0
2
4
0
1
0-1
1-0
0-1
1-0
A1
0
A0
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
A2
0ꢀ
0ꢀ
0ꢀ
0ꢀ
1ꢀ
1ꢀ
1ꢀ
1ꢀ
A1
0ꢀ
0ꢀ
1ꢀ
ꢀ1ꢀ
0ꢀ
0ꢀ
1ꢀ
1ꢀ
A0
0ꢀ
1ꢀ
ꢀ0ꢀ
1ꢀ
0ꢀ
1ꢀ
0ꢀ
1ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
0-1-2-3-4-5-6-7ꢀ
1-2-3-4-5-6-7-0ꢀ
ꢀ2-3-4-5-6-7-0-1ꢀ
ꢀ3-4-5-6-7-0-1-2ꢀ
4-5-6-7-0-1-2-3ꢀ
5-6-7-0-1-2-3-4ꢀ
6-7-0-1-2-3-4-5ꢀ
7-0-1-2-3-4-5-6ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
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
NotꢀSupportedꢀ
ꢀ
8ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
Fullꢀ
Pageꢀ
(y)
nꢀ=ꢀA0-A7ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
Cn,ꢀCnꢀ+ꢀ1,ꢀCnꢀ+ꢀ2ꢀ
Cnꢀ+ꢀ3,ꢀCnꢀ+ꢀ4...
…Cn - 1,
ꢀ
(location 0-y)
Cn…
Integrated Silicon Solution, Inc. — www.issi.comꢀ
17
Rev. A
03/19/08
ISSI [ INTEGRATED SILICON SOLUTION, INC ]
