82801FB Datasheet, PDF (376/786 Pages) Intel Corporation – Intel I/O Controller Hub 6 (ICH6) Family

LPC Interface Bridge Registers (D31:F0)
10.4.7
10.4.8
OCW1—Operational Control Word 1 (Interrupt Mask)
Register (LPC I/F—D31:F0)
Offset Address:
Default Value:
Master Controller – 021h
Slave Controller – 0A1h
00h
Attribute:
Size:
R/W
8 bits
Bit
Description
Interrupt Request Mask — R/W. When a 1 is written to any bit in this register, the corresponding
7:0
IRQ line is masked. When a 0 is written to any bit in this register, the corresponding IRQ mask bit is
cleared, and interrupt requests will again be accepted by the controller. Masking IRQ2 on the master
controller will also mask the interrupt requests from the slave controller.
OCW2—Operational Control Word 2 Register
(LPC I/F—D31:F0)
Offset Address:
Default Value:
Master Controller – 020h
Attribute:
Slave Controller – 0A0h
Size:
Bit[4:0]=undefined, Bit[7:5]=001
WO
8 bits
Following a part reset or ICW initialization, the controller enters the fully nested mode of
operation. Non-specific EOI without rotation is the default. Both rotation mode and specific EOI
mode are disabled following initialization.
Bit
Description
Rotate and EOI Codes (R, SL, EOI) — WO. These three bits control the Rotate and End of Interrupt
modes and combinations of the two.
000 = Rotate in Auto EOI Mode (Clear)
001 = Non-specific EOI command
010 = No Operation
7:5 ^{011 = *Specific EOI Command}
100 = Rotate in Auto EOI Mode (Set)
101 = Rotate on Non-Specific EOI Command
110 = *Set Priority Command
111 = *Rotate on Specific EOI Command
*L0 – L2 Are Used
4:3 OCW2 Select — WO. When selecting OCW2, bits 4:3 = “00”
Interrupt Level Select (L2, L1, L0) — WO. L2, L1, and L0 determine the interrupt level acted upon
when the SL bit is active. A simple binary code, outlined below, selects the channel for the command
to act upon. When the SL bit is inactive, these bits do not have a defined function; programming L2,
L1 and L0 to 0 is sufficient in this case.
2:0
Code Interrupt Level
000b
IRQ0/8
001b
IRQ1/9
010b
IRQ2/10
011b
IRQ3/11
Code
000b
001b
010b
011b
Interrupt Level
IRQ4/12
IRQ5/13
IRQ6/14
IRQ7/15
376
Intel^® I/O Controller Hub 6 (ICH6) Family Datasheet