4.29 Expansion ROM Base Address Register
The PCI2250 does not implement the expansion ROM remapping feature. The expansion ROM base address
register returns all 0s when read.
Bit
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Name
Type
Default
Bit
Expansion ROM base address
R
0
R
0
R
0
R
0
R
0
R
0
R
0
9
R
0
8
R
0
7
R
0
6
R
0
5
R
0
4
R
0
3
R
0
2
R
0
1
R
0
0
15
14
13
12
11
10
Name
Type
Default
Expansion ROM base address
R
0
R
0
R
0
R
0
R
0
R
0
R
0
R
0
R
0
R
0
R
0
R
0
R
0
R
0
R
0
R
0
Register:
Type:
Offset:
Default:
Expansion ROM base address
Read-only
38h
0000 0000h
4.30 Interrupt Line Register
The interrupt line register is read/write and is used to communicate interrupt line routing information. Since the bridge
does not implement an interrupt signal terminal, this register defaults to FFh.
Bit
7
6
5
4
3
2
1
0
Name
Type
Default
Interrupt line
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
Register:
Type:
Offset:
Default:
Interrupt line
Read/write
3Ch
FFh
4.31 Interrupt Pin Register
The bridge default state does not implement any interrupt terminals. Reads from bits 7–0 of this register return 0s.
Bit
7
6
5
4
3
2
1
0
Name
Type
Default
Interrupt pin
R
0
R
0
R
0
R
0
R
0
R
0
R
0
R
0
Register:
Type:
Offset:
Default:
Interrupt pin
Read-only
3Dh
00h
4–14
TI [ TEXAS INSTRUMENTS ]
