Chipset Configuration Registers
10.1.53 TCTL—TCO Configuration Register
Offset Address: 3000–3000h
Attribute:
Size:
R/W
8-bit
Default Value:
00h
Bit
Description
TCO IRQ Enable (IE) — R/W.
7
0 = TCO IRQ is disabled.
1 = TCO IRQ is enabled, as selected by the TCO_IRQ_SEL field.
6:3
Reserved
TCO IRQ Select (IS) — R/W. Specifies on which IRQ the TCO will internally appear.
If not using the APIC, the TCO interrupt must be routed to IRQ9-11, and that
interrupt is not sharable with the SERIRQ stream, but is shareable with other PCI
interrupts. If using the APIC, the TCO interrupt can also be mapped to IRQ20-23, and
can be shared with other interrupt.
000 = IRQ 9
001 = IRQ 10
010 = IRQ 11
011 = Reserved
2:0
100 = IRQ 20 (only if APIC enabled)
101 = IRQ 21 (only if APIC enabled)
110 = IRQ 22 (only if APIC enabled)
111 = IRQ 23 (only if APIC enabled)
When setting the these bits, the IE bit should be cleared to prevent glitching.
When the interrupt is mapped to APIC interrupts 9, 10 or 11, the APIC should be
programmed for active-high reception. When the interrupt is mapped to APIC
interrupts 20 through 23, the APIC should be programmed for active-low reception.
328
Datasheet
INTEL [ INTEL ]
