Intel
®
81341 and 81342—DDR SDRAM Memory Controller
Intel
®
81341 and 81342 I/O Processors
Developer’s Manual
December 2007
580
Order Number: 315037-002US
illustrates the 81341 and 81342 DDR SDRAM 64-bit Memory Address Map,
and
illustrates the Physical map of the 64-bit DDR SDRAM. The size of each
region is configured separately. The 32-bit region is only applicable when the 81341
and 81342 is connected to 64-bit DDR SDRAM memory. With 32-bit DDR SDRAM
attached to 81341 and 81342, all DDR SDRAM memory space behaves as 32-bit DDR
SDRAM and the value in S32SR is ignored.
When the 32-bit region defined by S32SR is greater than zero, bank 0s address space
is split into three regions as illustrated in
. The lowest addressable region
operates as a 32-bit region of size defined in the S32SR. A second region, contiguous
with the 32-bit region, and equal in size, is defined as invalid for the DDR SDRAM
memory space. This invalid region reflects the other half of the 64-bit DDR SDRAM
which is not used in the 32-bit region. Transactions which address this region results in
an error and interrupt to the Intel XScale
®
microarchitecture. The third region is
contiguous with the second and is the remainder of bank 0 address space, and is a
64-bit region.
The base address registers provide the starting address of the DDR memory space, and
must be aligned to the size of supported DDR memory. The smallest DDR memory bank
size supported is 256 MBytes. In this case, the base address registers (SDBR and
SDUBR) define the upper eight address bits of the starting address of the DDR SDRAM
memory space. The largest DDR memory supported is 4 GBytes. In this case, the base
address registers (SDBR and SDUBR) define the upper four address bits of the starting
address of the DDR SDRAM memory space.
Figure 80. DDR SDRAM 64-bit Memory Address Map
Figure 81. DDR SDRAM 64-bit Physical Map
A9482-01
64-bit Region
64-bit Region
Bank1
32-bit size
Bank0
SDBR
32-bit Region
32-bit size
SDUBR | SDBR
A9483-01
64-bit Region 1
64-bit Region 0
2xS32SR
63
0
SDBR
32-bit Region
SBR1
SBR0
SDUBR | SDBR
SBSR