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DSOCM Input Ports: Attributes
Attributes are inputs to the OCM controller from the FPGA fabric that must be connected to
initialize registers at FPGA power up, or following a processor reset. These inputs are used
to:
xDefine the DSOCM control register DCR addresses in the DCR memory space.
xDefine the 16MB memory locations for the DSOCM controller.
xEnable the DSOCM address decoder.
xDefine the operating characteristics for the bus interface circuitry.
Tabl e 3-4 describes the DSOCM attributes.

Table 3-4: DSOCM Attributes

Attribute Direction Description

DSCNTLVALUE[0:7] I nput This input bus is loaded into the DSCNTL register at FPGA power-
up. The value is used to define the basic operational characteristics of
the DSOCM controller. Application software can modify the default
value by writing to the DSCNTL register. See Figure3-11, page 162,
and Figure 3-12, page 163, for register bit definitions.
DSARCVALUE[0:7] Input This input bus is loaded into the DSARC register at FPGA power up.
It defines the 16 MB memory space location for the data-side memory
interface. See Figure3-11, page 162, and Figure 3-12, page 163, for
register bit definitions.
TIEDSOCMDCRADDR[0:7]
(Virtex-II Pro only)a
Input This input bus defines the eight most significant bits of the ten-bit
DCR address space for the DSOCM DCR contr ol and status r egis ters.
The two least significant bits are predefined within the DSOCM
controller. For example, if TIEDSOCMDCRADDR = 00_0001_11
then:
xDCR address of DSARC = 00_0001_1110 = 0x01E
xDCR address of DSCNTL = 00_0001_1111 = 0x01F
TIEDCRADDR[0:5]
(Virtex-4 only)a
Input This input bus defines the six most significant bits of the ten- bit DCR
address space for the DCR Control and Status registers associated
with the OCM, APUb, AND EMACc submodules.
For example, if TIEDCRADDR = 00_0001 then:
xDCR address of DSARC = 00_0001_0110 = 0x016
xDCR address of DSCNTL = 00_0001_0111 = 0x017
a. For more information, refer to the “Device-Control Register Interfaces” section in Chapter 2.
b. For more information, refer to Chapter 4, “PowerPC 405 APU Controller”.
c. For more information, refer to the Virtex-4 Ethernet Media Ac c ess Controller manual.