CMS4A16LAx–75Ex
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 gene-
rate 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, meaning
that the burst will wrap within the block if a boundary is reached.
The block is uniquely selected by A1-A8 when the burst
length is set to two; by A2-A8 when the burst length is set to
four; and by A3-A8 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.
Burst Type
The burst type can be set to either Sequential or Interleaved
by using the M3 bit in the Mode register. 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 2.
[4.5.6.7.8.9.10.]
Table 1. Mode Register Definition.
M13-
BA1
M12-
BA0
M11-
A11
M10-
A10
M9-A9
WB
M8-A8
M7-A7
M6-A6
M5-A5
M4-A4
M3-A3
BT
M2-A2
M1-A1
Burst Length
M0-A0
Reserved(Set to ‘0’)
Op Mode
Burst Length
CAS Latency
M2 M1 M0
M3=0
000
001
010
011
100
101
110
111
M6 M5 M4
000
001
010
011
100
101
110
111
1
2
4
8
Reserved
Reserved
Reserved
Full Page
CAS Latency
Reserved
1
2
3
Reserved
Reserved
Reserved
Reserved
M3=1
1
2
4
8
Reserved
Reserved
Reserved
Reserved
M8
0
-
M7
0
-
M3
0
1
M9
0
1
Burst Type
Sequential
Interleaved
Write Burst Mode
Prog. Burst Length
Single Mode Access
M6-M0
Defined
-
Operating Mode
Standard Operation
All other states reserved
Note :
4. For full-page accesses: y = 512
5. For a burst length of two, A1-A8 select the block-of-two burst; A0 selects the starting column within the block.
6. For a burst length of four, A2-A8 select the block-of-four burst; A0-A1 select the starting column within the block.
7. For a burst length of eight, A3-A8 select the block-of-eight burst; A0-A2 select the starting column within the block.
8. For a full-page burst, the full row is selected and A0-A8 select the starting column.
9. Whenever a boundary of the block is reached within a given sequence above, the following access wraps within the block.
10. For a burst length of one, A0-A8 select the unique column to be accessed,and mode register bit M3 is ignored.
Rev. 0.5, May. ‘07
8
FIDELIX [ FIDELIX ]
