Intel
®
81341 and 81342 I/O Processors
December 2007
Developer’s Manual
Order Number: 315037-002US
627
DDR SDRAM Memory Controller—Intel
®
81341 and 81342
7.8.1
SDRAM Initialization Register — SDIR
The DDR SDRAM Initialization Register (SDIR) is responsible for programming the
operation of the DDR SDRAM device state machines. The SDIR provides a method for
software to execute the DDR SDRAM initialization sequence (see
SDRAM Initialization” on page 594
provides the encoding that software can
use to initialize the SDRAM.
Note:
Software is responsible to provide all the parameters required for SDRAM DDR
commands, Mode Register and Extended Mode Register using the SDIR bit fields. For
example, parameters are not supplied by other memory-mapped registers.
Table 374. DDR SDRAM Initialization Register — SDIR
Bit
Default
Description
31
1
2
Chip Select (CS0#): This bit is used to select the DDR SDRAM bank 0.
30
1
2
Chip Select (CS1#): This bit is used to select the DDR SDRAM bank 1.
29:26
0
2
Reserved.
25:23
000
2
Bank Select Bits (BA[2:0]): These three bits are driven on the DDR SDRAM bank select bits (BA[2:0]).
These bits are used to select a DDR SDRAM Mode Register. Refer to
. Bit 23 drives Bank Address bit BA0, Bit 24 drives Bank Address bit BA1, and Bit
25 drives Bank Address bit BA2.
22:21
00
2
Reserved.
20:07
00000H
Address Bits (MA[14:0]): These fifteen bits are driven on the DDR SDRAM address bits (MA[14:0]). DDR
SDRAM Mode Register and Extended Mode Register operations use these address bits to carry Mode
Register parameters. Refer to
Table 365, “SDIR Encoding Examples” on page 596
that shows the Mode
Register parameters. Bit 07 drives address bit MA0, bit 08 drives address bit MA1, and so on.
06
1
2
Row Address Strobe (RAS#): This bit is used to drive the DDR SDRAM RAS strobe signal. The RAS
strobe forms part of the command field.
05
1
2
Column Address Strobe (CAS#): This bit is used to drive the DDR SDRAM CAS strobe signal. The CAS
strobe forms part of the command field.
04
1
2
Write Strobe (WE#): This bit is used to drive the DDR SDRAM write strobe signal. The write strobe
forms part of the command field.
03:00
0000
2
4-Bit Burst Code (DT[3:0]): These four bits represent the four-bit burst code DT0, DT1, DT2, and DT3
that are driven simultaneously on all the data lines during OCD adjust mode. Bit 0 represents DT0, bit 1
represents DT1, and so on.
PCI
IOP
Attributes
Attributes
28
24
20
16
12
8
4
0
31
rw
na
rw
na
rv
na
rv
na
rv
na
rv
na
rw
na
rw
na
rv
na
rv
na
rv
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
Attribute Legend:
RV = Reserved
PR = Preserved
RS = Read/Set
RW = Read/Write
RC = Read Clear
RO = Read Only
NA = Not Accessible
Intel XScale
®
microarchitecture Local Bus Address
offset
+1800H