Analog-to-Digital Converter (ADC)

3.4 Interrupts

When the AIEN bit is set, the ADC module is capable of generating a CPU interrupt after each ADC conversion. A CPU interrupt is generated if the COCO bit is at 0. The COCO bit is not used as a conversion complete flag when interrupts are enabled.

3.5 Wait Mode

The WAIT instruction can put the MCU in low power-consumption standby mode.

The ADC continues normal operation during wait mode. Any enabled CPU interrupt request from the ADC can bring the MCU out of wait mode. If the ADC is not required to bring the MCU out of wait mode, power down the ADC by setting ADCH[4:0] in the ADC status and control register before executing the WAIT instruction.

3.6 I/O Signals

The ADC module has 10 input signals that are shared with port B and port C.

3.6.1 ADC Analog Power Pin (VDDAD)

The ADC analog portion uses VDDAD as its power pin. Connect the VDDAD pin to the same voltage potential as VDD. External filtering may be necessary to ensure clean VDDAD for good results.

NOTE

Route VDDAD carefully for maximum noise immunity and place bypass capacitors as close as possible to the package.

3.6.2 ADC Analog Ground Pin (VSSAD)

The ADC analog portion uses VSSAD as its ground pin. Connect the VSSAD pin to the same voltage potential as VSS.

3.6.3 ADC Voltage Reference Pin (VREFH)

VREFH is the power supply for setting the reference voltage VREFH. Connect the VREFH pin to the same voltage potential as VDDAD. There will be a finite current associated with VREFH. See Chapter 19 Electrical

Specifications.

NOTE

Route VREFH carefully for maximum noise immunity and place bypass capacitors as close as possible to the package.

3.6.4 ADC Voltage Reference Low Pin (VREFL)

VREFL is the lower reference supply for the ADC. Connect the VREFL pin to the same voltage potential as VSSAD. A finite current will be associated with VREFL. See Chapter 19 Electrical Specifications.

NOTE

In the 56-pin shrink dual in-line package (SDIP), VREFL and VSSAD are tied together.

MC68HC908MR32 • MC68HC908MR16 Data Sheet, Rev. 6.1

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Freescale Semiconductor

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Freescale Semiconductor MC68HC908MR32, MC68HC908MR16 manual Interrupts, Wait Mode, I/O Signals

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.