Intel® 500 Series Chipset Family On-Package PCH Datasheet Volume 1

Datasheet

ID 631119
Date 13/07/2021 00:00:00
Public Content
Document Table of Contents

Interrupt Levels

Interrupts directed to the internal 8259s are active high. Refer to Advanced Programmable Interrupt Controller (APIC) (D31:F0) for information regarding the polarity programming of the I/O APIC for detecting internal interrupts.

If the interrupts are mapped to the 8259 or I/O APIC and set for level-triggered mode, they can be shared with legacy interrupts. They may be shared although it is unlikely for the operating system to attempt to do this.

If more than one timer is configured to share the same IRQ (using the TIMERn_​INT_​ROUT_​CNF fields), then the software must configure the timers to level-triggered mode. Edge-triggered interrupts cannot be shared.

Handling Interrupts

Section 2.4.6 of the IA-PC HPET Specification describes handling interrupts.

Issues Related to 64 bit Timers with 32 bit Processor

Section 2.4.7 of the IA-PC HPET Specification describes issues related to 64 bit timers with 32 bit processors.