Intel
®
81341 and 81342 I/O Processors
December 2007
Developer’s Manual
Order Number: 315037-002US
567
DDR SDRAM Memory Controller—Intel
®
81341 and 81342
7.3.1.2
Address Decode Blocks
Address Decode is performed for transactions from input North and South internal bus
ports to determine when the DMCU claims the transaction. The North internal bus port
claims transactions targeting the DDR SDRAM memory array space. The South internal
bus port claims transactions for two address ranges:
• DDR SDRAM memory array space
• Peripheral Memory-Mapped Register (PMMR) space
7.3.1.2.1 DDR SDRAM Memory Array Space
The DDR SDRAM Memory Array Space is accessed from either the North internal bus
port, South internal bus port, or the Application DMA ports using a Primary Memory
Window. The primary DDR SDRAM memory space is defined with the DDR SDRAM Base
Address Register (SDBR and SDUBR), the DDR SDRAM Bank Size Register (SDSR) and
the SDRAM Control 1 register (SDCR1). The transaction is intended for a DDR SDRAM
banks when the address is between the base registers (SDBR and SDUBR) and
between the boundaries programmed with SBSR and S32SR as defined in
7.3.3.3, “DDR SDRAM Bank Sizes and Configurations” on page 578
.
In addition, the Intel XScale® core can access part of the DDR SDRAM Memory Array
from the North internal bus port using a Secondary Memory Window. The Secondary
Memory Window is used in conjunction with the Primary Memory Window. The
Secondary Memory Window is setup using the Secondary SDRAM Base Register
(SSDBR) and the DDR SDRAM Bank Size Register (SBSR).
7.3.1.2.2 Memory-Mapped Register Space
The DMCU PMMR memory space is at o1800H t19FFH. The registers
are detailed in
Section 7.8, “Register Definitions” on page 625
Each port decodes inbound transactions for these address ranges. The Address Decode
blocks determine how the Memory Controller responds to inbound transactions. The
details of the address decode for each port is described below.
7.3.1.2.3 North Internal Bus Port Address Decode
North internal bus port transactions are decoded to determine when they address the
DDR Memory space. When the transaction addresses the DDR SDRAM Memory Space,
the transaction is queued in the North internal bus port queue.
7.3.1.2.4 South Internal Bus Port Address Decode
South internal bus port transactions are decoded to determine when they address the
DDR SDRAM Memory Space, the DMCU MMR Space, or the Messaging Unit Space.
When the transaction addresses either of these spaces, the transaction is claimed by
the South Internal Bus Port. When the transaction addresses the DDR SDRAM Memory
Space, the transaction is queued in the south internal bus Port transaction queue.
When the transaction addresses the DMCU MMR Space, the transaction is serviced by
accessing the Configuration Register block.
7.3.1.2.5 Application DMA Port Address Decode
The Application DMA Ports do not require any decode, and processes any transaction
received from the Application DMAs via the Application DMA DMCU Port.