starting location within the block. The programmed burst length applies to both READ
and WRITE bursts.
Figure 52: Mode Register 0 (MR0) Definitions
CL
BL
CAS# latency BT
PD
A9
A7 A6 A5 A4 A3
A8
A2 A1 A0
Mode register 0 (MR0)
Address bus
9
7
6
5
4
3
8
2
1
0
A10
A12 A11
A14
BA0
10
11
12
13
M3
0
1
READ Burst Type
Sequential (nibble)
Interleaved
CAS Latency
Reserved
5
6
7
8
9
10
11
12
13
M4
0
1
0
1
0
1
0
1
0
1
M2
0
1
M5
0
1
0
1
0
M6
0
1
0
15
DLL
Write Recovery
Reserved
5
6
7
8
10
12
14
WR
01
0
M12
0
1
Precharge PD
DLL off (slow exit)
DLL on (fast exit)
BA1
16
0
BA2
17
01
Burst Length
Fixed BL8
4 or 8 (on-the-fly via A12)
Fixed BC4 (chop)
Reserved
M0
0
1
0
1
M1
0
1
M9
0
1
0
1
0
1
0
1
M10
0
1
0
1
M11
0
1
M15
0
1
0
1
M16
0
1
Mode Register
Mode register 0 (MR0)
Mode register 1 (MR1)
Mode register 2 (MR2)
Mode register 3 (MR3)
A13
14
01
M8
0
1
DLL Reset
No
Yes
Note: 1. MR0[17, 14, 13, 7] are reserved for future use and must be programmed to 0.
Burst Type
Accesses within a given burst may be programmed to either a sequential or an inter-
ordering of accesses within a burst is determined by the burst length, the burst type,
and the starting column address. DDR3 only supports 4-bit burst chop and 8-bit burst
access modes. Full interleave address ordering is supported for READs, while WRITEs
are restricted to nibble (BC4) or word (BL8) boundaries.
2Gb: x4, x8, x16 DDR3 SDRAM
Mode Register 0 (MR0)
PDF: 09005aef826aaadc
2Gb_DDR3_SDRAM.pdf – Rev. K 04/10 EN
134
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