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Section 5 Interrupt Controller
5.1 Overview
5.1.1 Features
The interrupt controller has the following features:
•
Interrupt priority registers (IPRs) for setting interrupt priorities
Interrupts other than NMI can be assigned to two priority levels on a module-by-module basis
in interrupt priority registers A and B (IPRA and IPRB).
•
Three-level masking by the I and UI bits in the CPU condition code register (CCR)
•
Independent vector addresses
All interrupts are independently vectored; the interrupt service routine does not have to identify
the interrupt source.
•
Five external interrupt pins
NMI has the highest priority and is always accepted; either the rising or falling edge can be
selected. For each of IRQ
0
, IRQ
1
, IRQ
4
, and IRQ
5
, sensing of the falling edge or level sensing
can be selected independently.