Aic: advanced interrupt controller – Rainbow Electronics AT75C220 User Manual
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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