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MC908AZ60ACFUER Datasheet, PDF (28/414 Pages) Freescale Semiconductor, Inc – To provide the most up-to-date information, the revision of our documents on the World Wide Web will be the most current. Your printed copy may be an earlier revision. To verify you have the latest information available, refer to:

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General Description

NOTE

The following pin descriptions are just a quick reference. For a more

detailed representation, see Chapter 22 Input/Output Ports.

1.4.1 Power Supply Pins (VDD and VSS)

VDD and VSS are the power supply and ground pins. The MCU operates from a single power supply.

Fast signal transitions on MCU pins place high, short-duration current demands on the power supply. To

prevent noise problems, take special care to provide power supply bypassing at the MCU as shown in

Figure 1-6. Place the C1 bypass capacitor as close to the MCU as possible. Use a high-frequency

response ceramic capacitor for C1. C2 is an optional bulk current bypass capacitor for use in applications

that require the port pins to source high current levels.

MCU

VDD

VSS

C1

0.1 Î¼F

+

C2

VDD

NOTE: Component values shown represent typical applications.

Figure 1-6. Power Supply Bypassing

VSS is also the ground for the port output buffers and the ground return for the serial clock in the Serial

Peripheral Interface module (SPI). See Chapter 19 Serial Peripheral Interface (SPI).

NOTE

VSS must be grounded for proper MCU operation.

1.4.2 Oscillator Pins (OSC1 and OSC2)

The OSC1 and OSC2 pins are the connections for the on-chip oscillator circuit. See Chapter 10 Clock

Generator Module (CGM).

1.4.3 External Reset Pin (RST)

A 0 on the RST pin forces the MCU to a known startup state. RST is bidirectional, allowing a reset of the

entire system. It is driven low when any internal reset source is asserted. See Chapter 9 System

Integration Module (SIM) for more information.

1.4.4 External Interrupt Pin (IRQ)

IRQ is an asynchronous external interrupt pin. See Chapter 17 External Interrupt Module (IRQ).

MC68HC908AZ60A â¢ MC68HC908AS60A â¢ MC68HC908AS60E Data Sheet, Rev. 6

28

Freescale Semiconductor

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