82801BA Datasheet, PDF (416/498 Pages) Intel Corporation – Intel 82801BA I/O Controller Hub 2 (ICH2) and Intel 82801BAM I/O Controller Hub 2 Mobile

AC’97 Modem Controller Registers (D31:F6)
14.1.13
SID—Subsystem ID (Modem—D31:F6)
Address Offset:
Default Value:
Lockable:
2Fh–2Eh
0000h
No
Attribute:
Size:
Power Well:
Write-Once
16 bits
Core
The SID register, in combination with the Subsystem Vendor ID register, makes it possible for the
operating environment to distinguish one audio subsystem from another. This register is
implemented as a write-once register. Once a value is written to the register, the value can be read
back. Any subsequent writes will have no effect.
Bit
Description
15:0 Subsystem ID Value—Read/Write-Once.
14.1.14
INTR_LN—Interrupt Line Register (Modem—D31:F6)
Address Offset: 3Ch
Default Value: 00h
Lockable:
No
Attribute:
Size:
Power Well:
R/W
8 bits
Core
This register indicates which PCI interrupt line is used for the AC’97 module interrupt.
Bit
Description
7:0
Interrupt Line—R/W. This data is not used by the ICH2. It is used to communicate to software the
interrupt line that the interrupt pin is connected to.
14.1.15
INT_PIN—Interrupt Pin (Modem—D31:F6)
Address Offset: 3Dh
Default Value: 02h
Lockable:
No
Attribute:
Size:
Power Well:
RO
8 bits
Core
This register indicates which PCI interrupt pin is used for the AC ‘97 modem interrupt. The AC ‘97
interrupt is internally ORed to the interrupt controller with the PIRQB# signal.
Bit
Description
7:3 Reserved.
2:0 AC ‘97 Interrupt Routing—RO. Hardwired to 010b to select PIRQB#.
14-6
82801BA ICH2 and 82801BAM ICH2-M Datasheet