MC68HC05V12 Datasheet, PDF (60/246 Pages) Freescale Semiconductor, Inc – HCMOS Microcontreller Unit

Interrupts
Freescale Semiconductor, Inc.
IRQ PIN
IRQ VECTOR FETCH
RST
IRQA
LEVEL
(MASK OPTION)
IRQE
PC0
DRC0
DDRC0
DDRC7
DRC0
PC7
V_DD
IRQ
LATCH
R
V_DD
IRQPC
LATCH
R
TO BIH & BIL
INSTRUCTION
SENSING
IRQF
TO IRQ
PROCESSING
IN CPU
IPCF
IPCE
Figure 4-2. IRQ Function Block Diagram
Technical Data
The IRQ pin is one source of an external interrupt. All port C pins
(PC0–PC7) act as other external interrupt sources. These sources have
their own interrupt latch but are combined with IRQ into a single external
interrupt request.
The port C interrupt sources are negative (falling) edge-sensitive only.
Note that all port C pins are ANDed together to form the negative edge
signal which sets the corresponding flag bits. A high-to-low transition on
any port C pin configured as an interrupt input will, therefore, set the
respective flag bit. If a port C pin is to be used as an interrupt input, the
corresponding data direction and data bits must both be cleared. If either
the pin is configured as an output or the data bit is set, a falling edge on
the pin will not generate an interrupt. The IRQ pin interrupt source may
be selected to be either edge sensitive or edge and level sensitive
Interrupts
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MC68HC05V12 — Rev. 2.0