Motorola MC68HC05RC8 User Manual

Motorola

MC68HC05RC16 — Rev. 3.0

General Release Specification

MOTOROLA

Interrupts

37

General Release Specification — MC68HC05RC16

Section 4. Interrupts

4.1 Contents

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

CPU Interrupt Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38

Reset Interrupt Sequence. . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

Software Interrupt (SWI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

Hardware Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41

External Interrupt (IRQ/Port B Keyscan). . . . . . . . . . . . . . . . . .41

External Interrupt Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42

Carrier Modulator Transmitter Interrupt (CMT) . . . . . . . . . . . . .42

Core Timer Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43

4.2 Introduction

The MCU can be interrupted four different ways:

1. Nonmaskable software interrupt instruction (SWI)

2. External asynchronous interrupt (IRQ/port B keyscan)

3. Internal carrier modulator transmitter interrupt

4. Internal core timer interrupt