MC68HC05BD3 Datasheet, PDF (38/112 Pages) Motorola, Inc – HCMOS microcontroller

IRQN bit
&
+
&
External
Interrupt
V_DD
Request
4
IRQ pin
D
Q
C
I BIT (CCR)
Q
R
Power-On Reset
+
External Reset
External Interrupt
being serviced
(read of vectors)
(a) Interrupt Function Diagram
IRQ
Wired ORed
Interrupt signals
IRQ
t_ILIH
t_ILIL
t_ILIL
EDGE SENSITIVE TRIGGER
CONDITION
The minimum pulse width t_ILIH is one
internal bus period. The period t_ILIL
should not be less than the number of
t_CYC cycles it takes to execute the
interrupt service routine plus 21 tcyc
cycles.
LEVEL SENSITIVE TRIGGER
CONDITION
If after servicing an interrupt the IRQ
pin remains low, then the next interrupt
is recognized. Normally used with wired
OR connection.
Normally used with pull-up resistors for
wired-OR connection.
(b) Interrupt Mode Diagram
MOTOROLA
4-6
Figure 4-3 External Interrupt Circuit and Timing
RESETS AND INTERRUPTS
TPG
MC68HC05BD3