Intel
®
81341 and 81342 I/O Processors
December 2007
Developer’s Manual
Order Number: 315037-002US
739
Interrupt Controller Unit—Intel
®
81341 and 81342
11.0
Interrupt Controller Unit
This chapter describes the Intel
®
81341 and 81342 I/O Processors (81341 and 81342)
Interrupt Controller Unit. Operation modes, setup, external memory interface, and
implementation of interrupts are described in this chapter.
11.1
Overview
The interrupt control unit manages interrupt routing and interrupt sources to the Intel
XScale
®
processor.
interrupts are events causing a temporary break in program execution so the processor
can handle another task. Interrupts commonly request I/O services or synchronize the
processor with some external hardware activity. For interrupt handler portability across
Intel XScale
®
microarchitecture family (ARM* architecture compliant), the architecture
defines a consistent exception handling mechanism. To manage exceptions which
include interrupt requests in parallel with processor execution, the 81341 and 81342
provides an on-chip programmable interrupt controller.
Requests for interrupt service come from many sources and are prioritized such that
instruction execution is redirected only when an exception interrupt request is of higher
priority than that of the executing task. On the 81341 and 81342, interrupt requests
may originate from external hardware sources, internal peripherals or software. The
81341 and 81342 contains a number of integrated peripherals which may generate
interrupts, including the following:
The interrupt controller unit can also forward interrupts to the PCI interrupt pins
(
P_INT[D:A]#
) when the PCI-X interface is being used as an endpoint. Interrupts are
detected with the chip 8-bit interrupt port, an 8-bit GPIO port, and with a dedicated
High-Priority Interrupt (
HPI#
) input. Interrupt requests originate from software by the
SWI
instruction. Ultimately, all interrupt sources that are steered to the Intel XScale
®
processor processor are combined into one of two internal interrupt exceptions: IRQ
and FIQ.
• Application DMA Channel 0, 1 and 2
• I
2
C Bus Interface Units 0, 1 and 2
• UART 0 and 1
• ATU-X
• Peripheral Bus Interface Unit
• Messaging Unit
• Performance Monitoring Unit
• DDR SDRAM Memory Controller Unit
• ATU-E
• Inter-Processor Messaging Unit
• Inter-Processor Interrupt
• Timer 0, Timer 1 and Watch Dog
Timer
a
a. Per Intel XScale
®
processor
• SRAM Memory Controller Unit