MC68HC908QT1VDW Freescale Semiconductor, MC68HC908QT1VDW Datasheet - Page 73

• Manufacturer Part Number: MC68HC908QT1VDW
• Description: 8-bit Microcontrollers - MCU 8 Bit 8MHz
• Manufacturer: Freescale Semiconductor

Specifications of MC68HC908QT1VDW

• Product Category: 8-bit Microcontrollers - MCU
• Core: HC08
• Data Bus Width: 8 bit
• Maximum Clock Frequency: 8 MHz
• Program Memory Size: 1.5 KB
• Data Ram Size: 128 B
• On-chip Adc: No
• Operating Supply Voltage: 3.3 V to 5.5 V
• Operating Temperature Range: - 40 C to + 85 C
• Package / Case: SOIC-8
• Mounting Style: SMD/SMT
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Number Of Programmable I/os: 6
• Number Of Timers: 2
• Program Memory Type: Flash
• Factory Pack Quantity: 96
• Supply Voltage - Max: 5.5 V
• Supply Voltage - Min: 2.7 V

Chapter 8
External Interrupt (IRQ)
8.1 Introduction
The IRQ pin (external interrupt), shared with PTA2 (general purpose input) and keyboard interrupt (KBI),
provides a maskable interrupt input
8.2 Features
Features of the IRQ module include the following:
8.3 Functional Description
IRQ pin functionality is enabled by setting configuration register 2 (CONFIG2) IRQEN bit accordingly. A
zero disables the IRQ function and PTA2 will assume the other shared functionalities. A one enables the
IRQ function.
A low level applied to the external interrupt request (IRQ) pin can latch a CPU interrupt request.
Figure 8-2
Interrupt signals on the IRQ pin are latched into the IRQ latch. The IRQ latch remains set until one of the
following actions occurs:
The external interrupt pin is falling-edge-triggered out of reset and is software-configurable to be either
falling-edge or falling-edge and low-level triggered. The MODE bit in INTSCR controls the triggering
sensitivity of the IRQ pin.
Freescale Semiconductor
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External interrupt pin, IRQ
IRQ interrupt control bits
Programmable edge-only or edge and level interrupt sensitivity
Automatic interrupt acknowledge
Selectable internal pullup resistor
IRQ vector fetch — An IRQ vector fetch automatically generates an interrupt acknowledge signal
that clears the IRQ latch.
Software clear — Software can clear the IRQ latch by writing a 1 to the ACK bit in the interrupt
status and control register (INTSCR).
Reset — A reset automatically clears the IRQ latch.
shows the structure of the IRQ module.
MC68HC908QY/QT Family Data Sheet, Rev. 6
73