MC68HC908EY16 Datasheet, PDF (101/278 Pages) Motorola, Inc – Microcontrollers

Chapter 9
External Interrupt (IRQ)
9.1 Introduction
This section describes the non-maskable external interrupt (IRQ) input.
9.2 Features
Features include:
• Dedicated external interrupt pin (IRQ)
• Hysteresis buffer
• Programmable edge-only or edge- and level-interrupt sensitivity
• Automatic interrupt acknowledge
9.3 Functional Description
A logic 0 applied to the external interrupt pin can latch a central processor unit (CPU) interrupt request.
Figure 9-1 shows the structure of the IRQ module.
ACK
VECTOR
FETCH
DECODER
IRQ
V_DD
D ^CLR Q
CK
IRQ
LATCH
SYNCHRO-
NIZER
IMASK
TO CPU FOR
BIL/BIH
INSTRUCTIONS
IRQF
IRQ
INTERRUPT
REQUEST
MODE
HIGH
VOLTAGE
DETECT
Figure 9-1. IRQ Block Diagram
TO MODE
SELECT
LOGIC
MC68HC908EY16 • MC68HC908EY8 Data Sheet, Rev. 10
Freescale Semiconductor
101