82371SB datasheet(71/122 Pages) INTEL

71 / 122 page

82371FB (PIIX) AND 82371SB (PIIX3)

2.5.3.3.

ICW3—Initialization Command Word 3 Register

I/O Address:

INT CNTRL-1—021h

Default Value:

All bits undefined

Attribute:

Write Only

The meaning of ICW3 differs between CNTRL-1 and CNTRL-2. On CNTRL-1, the master controller, ICW3

indicates which CNTRL-1 IRQ line physically connects the INTR output of CNTRL-2 to CNTRL-1.

Bit

Description

7:3

Reserved. Must be programmed to all 0s.

Cascaded Mode Enable. This bit must be programmed to 1 selecting cascade mode.

1:0

Reserved. Must be programmed to all 0s.

2.5.3.4.

ICW3—Initialization Command Word 3 Register

I/O Address:

INT CNTRL-2—0A1h

Default Value:

All bits undefined

Attribute:

Write Only

On CNTRL-2 (the slave controller), ICW3 is the slave identification code broadcast by CNTRL-1.

Bit

Description

7:3

Reserved. Must be programmed to all 0s.

2:0

Slave Identification Code. Must be programmed to 010b.

2.5.3.5.

ICW4—Initialization Command Word 4 Register

I/O Address:

INT CNTRL-1—021h; INT CNTRL-2—0A1h

Default Value:

01h

Attribute:

Write Only

Both PIIX/PIIX3 interrupt controllers must have ICW4 programmed as part of their initialization sequence.

Bit

Description

7:5

Reserved. Must be programmed to all 0s.

Special Fully Nested Mode (SFNM). Bit 4, SFNM, should normally be disabled by writing a 0

to this bit. If SFNM=1, the special fully nested mode is programmed.

Buffered mode (BUF). Must be programmed to 0 selecting non-buffered mode.

Master/Slave in Buffered Mode. Should always be programmed to 0. Bit not used.

AEOI (Automatic End of Interrupt). This bit should normally be programmed to 0. This is the

normal end of interrupt. If this bit is 1, the automatic end of interrupt mode is programmed.

Microprocessor Mode. Must be programmed to 1 indicating an Intel Architecture-based

system.

82371SB Datasheet(PDF) 71 Page - Intel Corporation

82371SB Datasheet(HTML) 71 Page - Intel Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL