mc68hc705v12 Freescale Semiconductor, Inc, mc68hc705v12 Datasheet - Page 60

• Manufacturer Part Number: mc68hc705v12
• Description: M68hc05-based Mcu Hc05 Freescale Semiconductor
• Manufacturer: Freescale Semiconductor, Inc

Interrupts
Advance Information
IRQ VECTOR FETCH
PC0
PC7
IRQ PIN
IPCE
IRQA
IRQE
RST
DDRC0
DDRC7
DRC0
DRC0
(IN MOR)
LEVEL
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
Figure 4-2. IRQ Function Block Diagram
Freescale Semiconductor, Inc.
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IRQPC
LATCH
Interrupts
R
LATCH
IRQ
R
MC68HC705V12
TO BIH & BIL
INSTRUCTION
SENSING
IRQF
IPCF
TO IRQ
PROCESSING
IN CPU
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Rev. 3.0