Laptop User Manual
Registers
http://www.motorola.com/computer/literature 2-89
2
PPC Slave Offset/Attribute (0, 1 and 2) Registers
The PPC Slave Offset Registers (XSOFF0, XSOFF1, and XSOFF2)
contains offset information associated with the mapping of PPC memory
space to PCI memory I/O space. The field within the XSOFFx registers is
defined as follows:
XSOFFx PPC Slave Offset. This register contains a 16-bit offset
that is added to the upper 16 bits of the PPC address to
determine the PCI address used for transfers from the PPC
bus to PCI. This offset allows PCI resources to reside at
addresses that would not normally be visible from the
PPC bus.
The PPC Slave Attributes Registers (XSATT0, XSATT1, and XSATT2)
contain attribute information associated with the mapping of PPC memory
space to PCI memory I/O space. The bits within the XSATTx registers are
defined as follows:
REN Read Enable. If set, the corresponding PPC Slave is
enabled for read transactions.
WEN Write Enable. If set, the corresponding PPC Slave is
enabled for write transactions.
WPEN Write Post Enable. If set, write posting is enable for the
corresponding PPC Slave.
Address XSOFF0/XSATT0 - $FEFF0044
XSOFF1/XSATT1 - $FEFF004C
XSOFF2/XSATT2 - $FEFF0054
Bit
0
1
2
3
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5
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10
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Name XSOFFx XSATTx
REN
WEN
WPEN
MEM
IOM
Operation R/W R
R/W
R/W
R
R/W
R
R
R/W
R/W
Reset $0000 $00
0
0
0
0
0
0
0
0