ARM ARM7TDMI Hardware Reference Guide

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Programming the APB FPGA
9-3
ARM Development Board (ARM7TDMI Version)
Hardware Reference Guide
ARM DUI 0017C
9.2 Interrupt Controller
The interrupt controller differs from the standard design in that it has an extra register which
allows the source of the FIQ interrupt to be selected as any of the 15 IRQ sources (1–15) or
an external FIQ source pin.
9.2.1 Selecting the FIQ source
To select the FIQ source, write to the following 4-bit register:
ICBase + 0x114 r/w
FIQ_source_register
Program this register with any value from 0x0 to 0xF.
Source 0 is the external FIQ source which is an active low, level-sensitive input on the ASB
and APB expansion connectors. This input is pulled up on the ARM Development Board.
9.2.2 Bit allocation
The table on the right shows the bit assignment
in the IRQ interrupt controller:
Bit Interrupt Source
0 Unused
1 Soft interrupt
2 COMMRX from processor
3 COMMTX from processor
4 Timer 1 (internal)
5 Timer 2 (internal)
6 PC card slot A
7 PC card slot B
8 Serial port A
9 Serial port B
10 Parallel port
11 ASB expansion 0
12 ASB expansion 1
13 APB expansion 0
14 APB expansion 1
15 APB expansion 2
hrg.book Page 3 Wednesday, July 22, 1998 9:18 AM

ARM ARM7TDMI Specifications

General

Brand	ARM
Model	ARM7TDMI
Category	Computer Hardware
Language	English