Intel
®
81341 and 81342—DDR SDRAM Memory Controller
Intel
®
81341 and 81342 I/O Processors
Developer’s Manual
December 2007
634
Order Number: 315037-002US
7.8.6
Secondary SDRAM Base Register - SSDBR
This register indicates six bits of the beginning address (base address) of a Secondary
SDRAM Memory Window of SDRAM space. The secondary memory window is addressed
using a 32-bit address (upper 4 bits of the Intel XScale
®
microarchitecture 36-bit
address are zero). The secondary memory window defined by SSDBR[31:26] and
SBSR[21:16] addresses a range of the SDRAM space. If the SDRAM space is defined to
be less than 4 GBytes, the user must ensure that the secondary memory window is
defined so that its address range is mapped within the SDRAM space. Refer to
Figure 82, “Secondary DDR SDRAM Window Memory Map” on page 582
which shows
the valid address range for the secondary memory window relative to the SDRAM
space.
Note:
The Secondary SDRAM memory space must
never
be larger than the total SDRAM size
defined by the SBSR, or 2 GByte, whichever is smaller.
Note:
This register reads back after being written, before the Intel XScale
®
microarchitecture
performs transactions which address the DDR SDRAM.
Table 379. Secondary SDRAM Base Register - SSDBR
Bit
Default
Description
31:26
0
Secondary SDRAM Window Base Address:
These bits define part of the upper bits of the Secondary
DDR SDRAM window base address.
25:00
0
Reserved
PCI
IOP
Attributes
Attributes
28
24
20
16
12
8
4
0
31
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
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
+1980H