MC68HC05C8A Datasheet, PDF (41/158 Pages) Motorola, Inc – Microcontrollers

Technical Data — MC68HC05C8A • MC68HCL05C8A • MC68HSC05C8A
Section 4. Interrupts
4.1 Contents
4.2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.3 Hardware Controlled Interrupt Sequence . . . . . . . . . . . . . . . . . 43
4.4 Software Interrupt (SWI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
4.5 External Interrupt (IRQ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
4.6 Timer Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
4.7 Serial Communications Interrupt (SCI) . . . . . . . . . . . . . . . . . . . 45
4.8 Serial Peripheral Interrupt (SPI) . . . . . . . . . . . . . . . . . . . . . . . .46
4.2 Introduction
The microcontroller unit (MCU) can be interrupted five different ways:
• Four maskable hardware interrupts, IRQ (interrupt request),
SPI (serial peripheral interface), SCI (serial communications
interface), and timer
• Non-maskable software interrupt instruction (SWI)
Port B interrupts, if enabled, are combined with the IRQ to form a single
interrupt source.
Interrupts cause the processor to save register contents on the stack
and to set the interrupt mask (I bit) to prevent additional interrupts. The
RTI (return to interrupt) instruction causes the register contents to be
recovered from the stack and normal processing to resume.
MC68HC05C8A • MC68HCL05C8A • MC68HSC05C8A — Rev. 5.0
MOTOROLA
Interrupts
Technical Data
41