PLB PCI Full Bridge (v1.00a)
DS508 March 21, 2006
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29
Product Specification
EAR
LY
ACCESS
bus number. The highest subordinate bus number is also an 8-bit value. The fields are defined in
Table 12
. Reset clears all bits.
Table 12:
Bus Number/Subordinate Bus Number Register Bit Definitions (Bit Assignment Assumes 32-bit
Bus)
Bit(s)
Name
Access
Reset
Value
Description
0-7
D0- D7
Read
0x0
Reserved
8-15
D8 - D15
Read/Write
0x0
Bus number
16-23
D16 - D23
Read
0x0
Reserved
24-31
D24 - D31
Read/Write
0x0
Maximum subordinate bus number
IPIFBAR2PCIBAR_N High-Order Bits Register Description
When configured to include these registers (i.e.,
C_INCLUDE_BAROFFSET_REG=1)
, the values in the
registers are used to translate addresses on the PLB bus to the PCI. The register values are used instead
of the corresponding parameter C_IPIFBAR2PCIBAR_N for translation by high-order bit substitution.
The parameters C_IPIFBAR2PCIBAR_N have no effect on the bridge operation if the registers for
address translation are included.
The number of registers present is given by the number of IPIF BAR configured in the IPIF (i.e.,
C_IPIFBAR_NUM). The actual width of the Nth register is given by the number of high-order bits that
define the complete address range corresponding to the Nth IPIF BAR. When the register is read,
32-bits are returned with the low-order bits hard-wired to zero.
The IPIFBAR2PCIBAR_N registers are included in the bridge via the parameter
C_INCLUDE_BAROFFSET_REG.
These read/write registers allow dynamic, run-time changes of the high-order bits for the substitution
in the translation of an address from the PLB bus to the PCI bus. Low-order bits pass directly from the
PLB bus to the PCI bus. When the register is read, 32-bits are read with the low-order bits set to zero.
Table 13
shows the data format. The programmability of these registers allows PLB address
transactions to access any target on the PCI bus which has been arbitrarily assigned a PCI BAR by a
remote or local Host Bridge. Dynamic, run-time changes in the high-order bits for address translation
of PLB PCI bridge PCI BAR range translation to PLB slaves is not needed because the PLB slave
addresses are defined at build time.
Including these registers makes the parameters, C_IPIFBAR2PCIBAR_N, irrelevant because the value
in the Nth programmable register replaces the values of the corresponding parameter,
C_IPIFBAR2PCIBAR_N, in translating the PLB address to the PCI bus. When the registers are included,
the parameters, C_IPIFBAR2PCIBAR_N, for N=0 to C_IPIFBAR_NUM-1, have no effect.
Table 13:
IPIFBAR2PCIBAR_N High-Order Bits (Bit assignment assumes 32-bit bus)
Bit(s)
Name
Access
Reset
Value
Description
0-M
D0 - DM
Read/Write
0x0
M+1 high-order bits that are substituted in address
translation from Nth IPIFBAR access to PCI address
space
M+1-31
DM+1 - D31
Read Only
0x0
Low-order bits set to zero
