Data Sheet — MC68HC908MR32 • MC68HC908MR16
Section 8. External Interrupt (IRQ)
8.1 Introduction
8.2 Features
This section describes the external interrupt (IRQ) module, which supports external
interrupt functions.
Features of the IRQ module include:
•
•
A dedicated external interrupt pin, IRQ
Hysteresis buffers
8.3 Functional Description
A logic 0 applied to any of the external interrupt pins can latch a CPU interrupt
request. Figure 8-1 shows the structure of the IRQ module.
ACK1
VDD
CLR
D
Q
SYNCHRO-
NIZER
IRQ
INTERRUPT
REQUEST
CK
IRQ
IRQ
LATCH
IMASK1
MODE1
TO MODE
SELECT
LOGIC
HIGH
VOLTAGE
DETECT
Figure 8-1. IRQ Module Block Diagram
Addr.
Register Name
Bit 7
0
6
5
0
4
0
3
IRQF
0
2
0
1
Bit 0
Read:
Write:
Reset:
0
IRQ Status/Control Register
(ISCR)
See page 105.
IMASK1 MODE1
$003F
R
R
R
0
R
0
ACK1
0
0
0
0
0
R
= Reserved
Figure 8-2. IRQ I/O Register Summary
MC68HC908MR32 • MC68HC908MR16 — Rev. 6.0
MOTOROLA
Data Sheet
101
External Interrupt (IRQ)
FREESCALE [ Freescale ]
