8.10 Subsystem Identification Register
The subsystem identification register, used for system and option card identification purposes, may be required for
certain operating systems. This read-only register is initialized through the EEPROM and can be written through the
subsystem access register at PCI offset 8Ch (see Section 8.23). All bits in this register are reset by GRST only.
Bit
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Name
Type
Default
Subsystem identification
RU
0
RU
0
RU
0
RU
0
RU
0
RU
0
RU
0
RU
0
RU
0
RU
0
RU
0
RU
0
RU
0
RU
0
RU
0
RU
0
Register:
Offset:
Type:
Subsystem identification
2Eh
Read/Update
0000h
Default:
8.11 Capabilities Pointer Register
The power management capabilities pointer register provides a pointer into the PCI configuration header where the
power-management register block resides. Since the PCI power management registers begin at 80h, this read-only
register is hardwired to 80h.
Bit
7
6
5
4
3
2
1
0
Name
Type
Default
Capabilities pointer
R
1
R
0
R
0
R
0
R
0
R
0
R
0
R
0
Register:
Offset:
Type:
Capabilities pointer
34h
Read-only
80h
Default:
8.12 Interrupt Line Register
The interrupt line register is programmed by the system and indicates to the software which interrupt line the SD host
controller has assigned to it. The default value of this register is FFh, indicating that an interrupt line has not yet been
assigned to the function.
Bit
7
6
5
4
3
2
1
0
Name
Type
Default
Interrupt line
RW
1
RW
1
RW
1
RW
1
RW
1
RW
1
RW
1
RW
1
Register:
Offset:
Type:
Interrupt line
3Ch
Read/Write
FFh
Default:
8−8