12. Register Descriptions
269
PowerSpan II User Manual
80A1010_MA001_09
Integrated Device Technology
www.idt.com
BAR_EN
R/W
P1_RST
1
EEPROM
PCI Base Address Register Enable
When this bit is set, the P1_BSTx register is Read/Write and
visible to PCI BIOS Configuration cycles. When this bit is
disabled, the P1_BSTx register is not visible in PCI-1
Configuration space and is read zero only.
Writes to P1_BSTx have no effect when this bit is cleared.
This effectively disables the PowerSpan II P1_BSTx Image
and PowerSpan II does not request PCI Memory space for
the image. If the user is clearing this bit, they must also clear
P1_BSTx.
0 = Disable
1 = Enable
MD_EN
R/W
P1_RST
0
Master Decode Enable
Enables master decode when the internal PCI arbiter is in
use —when the P1_ARB_EN bit in the
is set. If MD_EN is cleared,
only the PCI Address and Command are used for transaction
decode. If MD_EN is set, the originating master is included in
the transaction decode. A transaction is claimed only if it
originates from the master(s) specified in P1_TIx_TADDR.
0=Disable
1=Enable
BS[3:0]
R/W
P1_RST
0
EEPROM
Block Size
(64 Kbyte * 2
BS
)
The block size specifies the size of the image, address lines
compared and address lines translated (see
MODE R/W
P1_RST
0
Image
Mode
Determines if the image is used to generate Memory or IO
commands on PCI. The MODE is only applicable if the
destination is the alternate PCI bus.
0 = Memory command generation
1 = I/O command generation or 4 byte memory read (see
DEST
R/W
P1_RST
0
Destination Bus
Selects the destination bus for the transaction.
0 = Processor Bus
1 = PCI-2 Bus
Single PCI PowerSpan II: Reserved
Processor Bus is the only destination.
Name
Type
Reset
By
Reset
State
Function