LPC Interface Bridge Registers (D31:F0)
13.4.4
ICW3—Master Controller Initialization Command
Word 3 Register (LPC I/F—D31:F0)
Offset Address: 21h
Attribute:
Size:
WO
8 bits
Default Value:
All bits undefined
Bit
Description
7:3
2
0 = These bits must be programmed to 0.
Cascaded Interrupt Controller IRQ Connection — WO. This bit indicates that the
slave controller is cascaded on IRQ2. When IRQ8#–IRQ15 is asserted, it goes through
the slave controller’s priority resolver. The slave controller’s INTR output onto IRQ2.
IRQ2 then goes through the master controller’s priority solver. If it wins, the INTR
signal is asserted to the processor, and the returning interrupt acknowledge returns the
interrupt vector for the slave controller.
1 = This bit must always be programmed to a 1.
1:0
0 = These bits must be programmed to 0.
13.4.5
ICW3—Slave Controller Initialization Command
Word 3 Register (LPC I/F—D31:F0)
Offset Address: A1h
Attribute:
Size:
WO
8 bits
Default Value:
All bits undefined
Bit
Description
7:3
0 = These bits must be programmed to 0.
Slave Identification Code — WO. These bits are compared against the slave
identification code broadcast by the master controller from the trailing edge of the first
internal INTA# pulse to the trailing edge of the second internal INTA# pulse. These bits
must be programmed to 02h to match the code broadcast by the master controller.
When 02h is broadcast by the master controller during the INTA# sequence, the slave
controller assumes responsibility for broadcasting the interrupt vector.
2:0
Datasheet
427
INTEL [ INTEL ]
