beautypg.com

Aic: advanced interrupt controller – Rainbow Electronics AT75C220 User Manual

Page 51

background image

AT75C220

51

AIC: Advanced Interrupt Controller

The AT75C220 integrates the Atmel advanced interrupt
controller (AIC). For details on this peripheral, refer to the
datasheet, literature number 1246.

The interrupt controller is connected to the fast interrupt
request (NFIQ) and the standard interrupt request (NIRQ)
inputs of the ARM7TDMI processor. The processor’s NFIQ
line can only be asserted by the external fast interrupt
request input (FIQ). The NIRQ line can be asserted by the

interrupts generated by the on-chip peripherals and the two
external interrupt request lines, IRQ0 to IRQ1.

An 8-level priority encoder allows the user to define the pri-
ority between the different interrupt sources. Internal
sources are programmed to be level-sensitive or edge-trig-
gered. External sources can be programmed to be positive-
or negative-edge triggered or high- or low-level sensitive.

Figure 13. Advanced Interrupt Controller Block Diagram

Table 17. Interrupt Sources

Interrupt Source

Interrupt Name

Interrupt Description

0

FIQ

Fast Interrupt (LOWP)

1

WDT

Watchdog Interrupt

2

SWI

Software Interrupt

3

UARTA

USART A Interrupt

4

TC0

Timer Channel 0 Interrupt

5

TC1

Timer Channel 1 Interrupt

6

TC2

Timer Channel 2 Interrupt

7

PIOA

PIO A Interrupt

8

MACA

MAC A Interrupt

9

SPI

Serial Peripheral Interface

10

IRQ0

External Interrupt

11

IRQ1

External Interrupt

12

OAKA

OAK Semaphore Interrupt

13

MACB

MAC B Interrupt

Control

Logic

Memorization

Memorization

Prioritization

Controller

NIRQ

Manager

NFIQ

Manager

FIQ Source

Advanced Peripheral

Bus (APB)

Internal Interrupt Sources

External Interrupt Sources

ARM7TDMI

Core

NFIQ

NIRQ