82801BA Datasheet, PDF (295/498 Pages) Intel Corporation – Intel 82801BA I/O Controller Hub 2 (ICH2) and Intel 82801BAM I/O Controller Hub 2 Mobile

LPC Interface Bridge Registers (D31:F0)
9.4
8259 Interrupt Controller (PIC) Registers
9.4.1 Interrupt Controller I/O MAP
The interrupt controller registers are located at 20h and 21h for the master controller (IRQ[0:7]),
and at A0h and A1h for the slave controller (IRQ[8:13]). These registers have multiple functions
depending on the data written to them. Table 9-3 lists the different register possibilities for each
address.
Table 9-3. PIC Registers
Port
Aliases
24h, 28h,
20h
2Ch, 30h,
34h, 38h, 3Ch
25h, 29h,
21h
2Dh, 31h,
35h, 39h, 3Dh
A4h, A8h,
A0h
ACh, B0h,
B4h, B8h, BCh
A5h, A9h,
A1h
ADh, B1h,
B5h, B9h, BDh
4D0h
–
4D1h
–
Register Name/Function
Master PIC ICW1 Init. Cmd Word 1 Register
Master PIC OCW2 Op Ctrl Word 2 Register
Master PIC OCW3 Op Ctrl Word 3 Register
Master PIC ICW2 Init. Cmd Word 2 Register
Master PIC ICW3 Init. Cmd Word 3 Register
Master PIC ICW4 Init. Cmd Word 4 Register
Master PIC OCW1 Op Ctrl Word 1 Register
Slave PIC ICW1 Init. Cmd Word 1 Register
Slave PIC OCW2 Op Ctrl Word 2 Register
Slave PIC OCW3 Op Ctrl Word 3 Register
Slave PIC ICW2 Init. Cmd Word 2 Register
Slave PIC ICW3 Init. Cmd Word 3 Register
Slave PIC ICW4 Init. Cmd Word 4 Register
Slave PIC OCW1 Op Ctrl Word 1 Register
Master PIC Edge/Level Triggered Register
Slave PIC Edge/Level Triggered Register
Default Value
Undefined
001XXXXXb
X01XXX10b
Undefined
Undefined
01h
00h
Undefined
001XXXXXb
X01XXX10b
Undefined
Undefined
01h
00h
00h
00h
Type
WO
WO
R/W
WO
WO
WO
R/W
WO
WO
R/W
WO
WO
WO
R/W
R/W
R/W
82801BA ICH2 and 82801BAM ICH2-M Datasheet
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