EMIF
7.3.5.3
SDRAM_CONFIG Register (offset = 8h) [reset = 0h]
SDRAM_CONFIG is shown in
and described in
Figure 7-93. SDRAM_CONFIG Register
31
30
29
28
27
26
25
24
reg_sdram_type
reg_ibank_pos
reg_ddr_term
R/W-0h
R/W-0h
R/W-0h
23
22
21
20
19
18
17
16
reg_ddr2_ddqs
reg_dyn_odt
reg_ddr_disable_dll
reg_sdram_drive
reg_cwl
R/W-0h
R/W-0h
R/W-0h
R/W-0h
R/W-0h
15
14
13
12
11
10
9
8
reg_narrow_mode
reg_cl
reg_rowsize
R/W-0h
R/W-0h
R/W-0h
7
6
5
4
3
2
1
0
reg_rowsize
reg_ibank
reg_ebank
reg_pagesize
R/W-0h
R/W-0h
R/W-0h
R/W-0h
LEGEND: R/W = Read/Write; R = Read only; W1toCl = Write 1 to clear bit; -n = value after reset
Table 7-113. SDRAM_CONFIG Register Field Descriptions
Bit
Field
Type
Reset
Description
31-29
reg_sdram_type
R/W
0h
SDRAM Type selection.
Set to 0 for DDR1, set to 1 for LPDDR1, set to 2 for DDR2, set to 3
for DDR3.
All other values are reserved.
28-27
reg_ibank_pos
R/W
0h
Internal bank position.
Set to 0 to assign internal bank address bits from lower OCP
address bits, as shown in the tables for OCP Address to
DDR2/3/mDDR Address Mapping.
Set to 1, 2, or 3 to assign internal bank address bits from higher
OCP address, as shown in the tables for OCP Address to
DDR2/3/mDDR Address Mapping.
26-24
reg_ddr_term
R/W
0h
DDR2 and DDR3 termination resistor value.
Set to 0 to disable termination.
For DDR2, set to 1 for 75 ohm, set to 2 for 150 ohm, and set to 3 for
50 ohm.
For DDR3, set to 1 for RZQ/4, set to 2 for RZQ/2, set to 3 for RZQ/6,
set to 4 for RZQ/12, and set to 5 for RZQ/8.
All other values are reserved.
23
reg_ddr2_ddqs
R/W
0h
DDR2 differential DQS enable.
Set to 0 for single ended DQS.
Set to 1 for differential DQS.
22-21
reg_dyn_odt
R/W
0h
DDR3 Dynamic ODT.
Set to 0 to turn off dynamic ODT.
Set to 1 for RZQ/4 and set to 2 for RZQ/2.
All other values are reserved.
20
reg_ddr_disable_dll
R/W
0h
Disable DLL select.
Set to 1 to disable DLL inside SDRAM.
19-18
reg_sdram_drive
R/W
0h
SDRAM drive strength.
For DDR1/DDR2, set to 0 for normal, and set to 1 for weak drive
strength.
For DDR3, set to 0 for RZQ/6 and set to 1 for RZQ/7.
For LPDDR1, set to 0 for full, set to 1 for 1/2, set to 2 for 1/4, and set
to 3 for 1/8 drive strength.
All other values are reserved.
17-16
reg_cwl
R/W
0h
DDR3 CAS Write latency.
Value of 0, 1, 2, and 3 (CAS write latency of 5, 6, 7, and 8) are
supported.
Use the lowest value supported for best performance.
All other values are reserved.
426
Memory Subsystem
SPRUH73H – October 2011 – Revised April 2013
Copyright © 2011–2013, Texas Instruments Incorporated