IS42RM Просмотр технического описания (PDF) - Integrated Silicon Solution
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IS42RM Datasheet PDF : 33 Pages
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IS42SM/RM/VM16400K
Figure4: Mode Register Definition
BA1 BA0 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0
Address Bus
13 12 11 10
9
8
7
0
0
0
0 WB 0
0
6
5
4
3
CAS Latency
BT
2
1
0
Burst Length
Mode Register (Mx)
M9
Write Burst Mode
0 Burst Read and Burst Write
1 Burst Read and Single Write
M6 M5 M4 CAS Latency
000
Reserved
001
Reserved
010
2
011
3
100
Reserved
101
Reserved
110
Reserved
111
Reserved
M3 Burst Type
0 Sequential
1 Interleave
Burst Length
M2 M1 M0
M3 = 0
M3 = 1
000
1
1
001
2
2
010
4
4
011
8
8
1 0 0 Reserved Reserved
1 0 1 Reserved Reserved
1 1 0 Reserved Reserved
1 1 1 Full Page Reserved
Note: M13(BA1) and M12(BA0) must be set to “0” to select Mode Register (vs. the Extended Mode Register)
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 the burst length, the burst type and the starting column
address, as shown in Table 3.
Table 3: Burst Definition
Starting Column Order of Access Within a Burst
Burst
Address
Length
A2
A1 A0
Sequential
Interleaved
0
0-1
0-1
2
1
1-0
1-0
00
0-1-2-3
0-1-2-3
01
1-2-3-0
1-0-3-2
4
10
2-3-0-1
2-3-0-1
11
3-0-1-2
3-2-1-0
0
0 0 0-1-2-3-4-5-6-7 0-1-2-3-4-5-6-7
0
0 1 1-2-3-4-5-6-7-0 1-0-3-2-5-4-7-6
0
1 0 2-3-4-5-6-7-0-1 2-3-0-1-6-7-4-5
0
1 1 3-4-5-6-7-0-1-2 3-2-1-0-7-6-5-4
8
1
0 0 4-5-6-7-0-1-2-3 4-5-6-7-0-1-2-3
1
0 1 5-6-7-0-1-2-3-4 5-4-7-6-1-0-3-2
1
1 0 6-7-0-1-2-3-4-5 6-7-4-5-2-3-0-1
1
1 1 7-0-1-2-3-4-5-6 7-6-5-4-3-2-1-0
Full
Page
n=A0-7
(Location 0-255)
Cn, Cn+1. Cn+2,
Cn+3, Cn+4…
…Cn-1, Cn...
Not Supported
Note :
1. For full-page accesses: y = 256
2. For a burst length of two, A1-A7 select the block-
of-two burst; A0 selects the starting column within the
block.
3. For a burst length of four, A2-A7 select the block-
of-four burst; A0-A1 select the starting column within
the block.
4. For a burst length of eight, A3-A7 select the
block-of-eight burst; A0-A2 select the starting column
within the block.
5. For a full-page burst, the full row is selected and A0-A7
select the starting column.
6. Whenever a boundary of the block is reached within a
given sequence above, the following access wraps
within the block.
7. For a burst length of one, A0-A7 select the unique
column to be accessed, and mode register bit M3 is
ignored.
Rev. A | August 2012
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