Intel 21555 - Manual (Page 173)

21555 Non-Transparent PCI-to-PCI Bridge User Manual 173
List of Registers
Table 102. Primary Clear IRQ and Secondary Clear IRQ Registers
These registers affect primary and secondary interrupts in the same way and are described together.
Bit Name R/W Description
15:0 CLR_IRQ R/W1TC
This register controls the state of the Primary or Secondary Interrupt
Request bits.
• When 0, Does not cause the corresponding primary or secondary
interrupt signal to be asserted.
• When 1, the primary or secondary interrupt signal is asserted when
the corresponding IRQ Mask bit is zero.
Writing a 1 to a bit in this register clears the corresponding interrupt
request bit to 0. Writing a 0 to any bit in this register has no effect.
Reading this register returns the current status of the interrupt
request bits.
• Reset value is 0
Table 103. Primary Set IRQ and Secondary Set IRQ Registers
Bit Name R/W Description
15:0 SET_IRQ R/W1TS
This register controls the state of the Primary or Secondary Interrupt
Request bits.
• When 0, Does not cause the corresponding primary or secondary
interrupt signal to be asserted.
• When 1, the primary or secondary interrupt signal is asserted if the
corresponding IRQ Mask bit is zero.
Writing a 1 to a bit in this register sets the corresponding interrupt
request bit to 1. Writing a 0 to any bit in this register has no effect.
Reading this register returns the current status of the interrupt
request bits.
• Reset value is 0
Primary Clear IRQ Secondary Clear IRQ
Byte Offset: 099:098h 09B:09Ah
These registers affect primary and secondary interrupts in the same way and are described together.
Offsets Primary Set IRQ Secondary Set IRQ
Byte 09D:09Ch 09F:09Eh