General Description

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 Figure 1-4shows. 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

∝F

+

 

C2

1–10 ∝F

VDD

Note: Component values shown represent typical applications.

Figure 1-4. Power Supply Bypassing

1.4.2 Oscillator Pins (OSC1 and OSC2)

The OSC1 and OSC2 pins are the connections for the on-chip oscillator circuit. For more detailed information, see Chapter 4 Clock Generator Module (CGM).

1.4.3 External Reset Pin (RST)

A logic 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 14 System Integration Module (SIM).

1.4.4 External Interrupt Pin (IRQ)

IRQ is an asynchronous external interrupt pin. See Chapter 8 External Interrupt (IRQ).

1.4.5 CGM Power Supply Pins (VDDA and VSSAD)

VDDA and VSSAD are the power supply pins for the analog portion of the clock generator module (CGM). Decoupling of these pins should be per the digital supply. See Chapter 4 Clock Generator Module (CGM).

MC68HC908MR32 • MC68HC908MR16 Data Sheet, Rev. 6.1

22

Freescale Semiconductor

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Freescale Semiconductor MC68HC908MR32 Power Supply Pins VDD and VSS, Oscillator Pins OSC1 and OSC2, External Reset Pin RST
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MC68HC908MR16, MC68HC908MR32 specifications

Freescale Semiconductor's MC68HC908MR32 and MC68HC908MR16 microcontrollers are part of the popular HC08 family, designed primarily for embedded applications. These microcontrollers are particularly favored in automotive, industrial, and consumer product sectors due to their reliability and versatility.

One of the standout features of the MC68HC908MR series is its CMOS technology, which enhances performance while minimizing power consumption. This makes these microcontrollers suitable for battery-operated devices. They operate at a maximum clock frequency of 2 MHz and offer a 16-bit architecture, providing a solid balance between processing power and efficiency.

The MC68HC908MR32 variant is equipped with 32KB of flash memory, which allows for the storage of complex programs and extensive data handling. In contrast, the MC68HC908MR16 features 16KB of flash memory, making it ideal for simpler applications. Both microcontrollers also come with 1KB of RAM, enabling efficient data processing and real-time operations.

Another significant characteristic of these microcontrollers is their integrated peripherals. They come with multiple input/output (I/O) pins, which allow for connectivity with various sensors and actuators. The built-in timer systems offer precise timing control for automotive and industrial applications, while the Analog-to-Digital Converter (ADC) provides essential conversion capabilities for various analog signals.

For communication purposes, the MC68HC908MR series includes a serial communication interface, enabling easy integration with other devices and systems. This versatility facilitates the development of complex systems that require interaction with external components.

Security is another crucial aspect of these microcontrollers. They have built-in fail-safe mechanisms to ensure reliable operation under various conditions, making them suitable for critical systems. Additionally, their robust architecture helps to safeguard against potential disruptions or attacks.

In summary, Freescale Semiconductor's MC68HC908MR32 and MC68HC908MR16 microcontrollers are key players in the embedded systems landscape. Their blend of power efficiency, integrated features, and scalability ensures they remain relevant for a wide array of applications, making them a favored choice among engineers and developers looking for dependable solutions in a competitive market.
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