Programming 35
PCI
Base
Address
Register
1
contains
the
starting
address
for
I/O
mapped
accesses
to
Local
Configuration
Registers.
The
value
in
this
register
is
loaded
by
the
system
BIOS.
PCI
Base
Address
Register
2
contains
the
starting
address
for
memory
mapped
accesses
to
the
RFM
Control
and
Status
Registers.
The
value
in
this
register
is
loaded
by
the
system
BIOS.
Table 3-12 PCI Base Address Register 1 for Access to Local Configuration Registers
PCIBAR1: Offset $14
Bit
Description
Read
Write
*Value after
PCI Reset
0
Memory Space Indicator
.
A zero (0) indicates the register maps into Memory Space.
A one (1) indicates the register maps into I/O Space.
(
NOTE
: Hardcoded to one (1).)
Yes
No
1
1
Reserved
. Yes
No
0
7:2
I/O Base Address
. Base Address for I/O access to Local
Configuration registers (requires 256 bytes).
(
NOTE
: Hardcoded to $0.)
Yes
No
$0
31:8
I/O Base Address
. I/O Base Address for access to Local
Configuration registers.
Yes
Yes
$0
*
NOTE
: This register will be altered by the system BIOS during the system boot process. I/O Accesses not supported.
Table 3-13 PCI Base Address Register 2 for Access to RFM Control and Status Registers
PCIBAR2: Offset $18
Bit
Description
Read
Write
*Value after
PCI Reset
0
Memory Space Indicator
.
A zero (0) indicates the register maps into Memory Space.
A one (1) indicates the register maps into I/O Space.
Yes
No
0
2:1
Register Location
. Values:
00 - Locate anywhere in 32-bit Memory Address Space.
01 - Locate below 1 MByte Memory Address Space.
10 - Locate anywhere in 64-bit Memory Address Space.
11 - Reserved
If I/O Space, Bit 1 is always 0 and Bit 2 is included in the base
address.
Yes
Mem: No I/O:
Bit 1 no,
Bit 2 yes
00
3
Prefetchable
(If Memory Space).
A one (1) indicates there are no side effects on reads.
If I/O Space, Bit 3 is included in the base address.
Yes
Mem: No I/O:
Yes
0
7:4
Memory Base Address bits hardwired to zero for 256 bytes.
Yes
No
0000
31:8
Memory Base Address
. Memory Base Address for access to
RFM registers.
Yes
Yes
$0
*
NOTE
: This register will be altered by the system BIOS during the system boot process.