Intel
®
81341 and 81342 I/O Processors
December 2007
Developer’s Manual
Order Number: 315037-002US
171
Address Translation Unit (PCI-X)—Intel
®
81341 and 81342
2.13.24 ATU Interrupt Line Register - ATUILR
ATU Interrupt Line Register bit definitions adhere to PCI Local Bus Specification,
Revision 2.3. This register identifies the system interrupt controller's interrupt request
lines which connect to the device's PCI interrupt request lines (as specified in the
interrupt pin register).
In a PC environment, for example, the register values and corresponding connections
are:
• 0 (00H) through 15 (0FH) correspond to IRQ0 through IRQ15
• 16 (10H) through 254 (FEH) are reserved
• 255 (FFH) indicates “unknown” or “no connection”
The operating system or device driver can examine each device’s interrupt pin and
interrupt line register to determine which system interrupt request line the device uses
to issue requests for service.
Table 47. ATU Interrupt Line Register - ATUILR
Bit
Default
Description
07:00
FFH
Interrupt Assigned - system-assigned value identifies which system interrupt controller’s interrupt
request line connects to the device's PCI interrupt request lines (as specified in the interrupt pin
register).
A value of FFH signifies “no connection” or “unknown”.
PCI
IOP
Attributes
Attributes
7
4
0
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Attribute Legend:
RV = Reserved
PR = Preserved
RS = Read/Set
RW = Read/Write
RC = Read Clear
RO = Read Only
NA = Not Accessible
Register Offset
+03CH