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| MC68HC711D3_05 Datasheet, PDF (17/138 Pages) Freescale Semiconductor, Inc – Microcontrollers | |||
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MCU
EXTAL
XTAL
NC OR
10Kâ100K
LOAD
4xE
CMOS-COMPATIBLE
EXTERNAL OSCILLATOR
Interrupt Request (IRQ)
FIRST MCU
EXTAL
10 M
XTAL
4xE
CRYSTAL
25 pF *
25 pF *
SECOND MCU
EXTAL
NC OR
10Kâ100K
LOAD
XTAL
MCU
EXTAL
10 M
XTAL
4xE
CRYSTAL
25 pF *
25 pF *
* Values includes all stray capacitances.
Figure 1-5. Oscillator Connections
1.9 Interrupt Request (IRQ)
The IRQ input provides a means of applying asynchronous interrupt requests to the microcontroller unit
(MCU). Either negative edge-sensitive triggering or level-sensitive triggering is program selectable by
using the IRQE bit of the OPTION register. IRQ is always configured to level-sensitive triggering at reset.
While the programmable read-only memory (PROM) is being programmed, this pin provides the chip
enable (CE) signal. To prevent accidental programming of the PROM during reset, an external resistor is
required on IRQ to pull the pin to VDD.
MC68HC711D3 Data Sheet, Rev. 2.1
Freescale Semiconductor
17
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