Monotonicity | Freescale Semiconductor MC68HC908MR16, MC68HC908MR32

Functional Description

significant bits (LSB), located in the ADC data register low, ADRL, can be ignored. However, ADRL must be read after ADRH or else the interlocking will prevent all new conversions from being stored.

Right justification will place only the two MSBs in the corresponding ADC data register high, ADRH, and the eight LSBs in ADC data register low, ADRL. This mode of operation typically is used when a 10-bit unsigned result is desired.

Left justified sign data mode is similar to left justified mode with one exception. The MSB of the 10-bit result, AD9 located in ADRH, is complemented. This mode of operation is useful when a result, represented as a signed magnitude from mid-scale, is needed. Finally, 8-bit truncation mode will place the eight MSBs in ADC data register low, ADRL. The two LSBs are dropped. This mode of operation is used when compatibility with 8-bit ADC designs are required. No interlocking between ADRH and ADRL is present.

NOTE

Quantization error is affected when only the most significant eight bits are used as a result. See Figure 3-3.

8-BIT 10-BIT RESULT RESULT

003

00B

00A

009

002008

007

006

005

001004

003

002

001

000 000

IDEAL 8-BIT CHARACTERISTIC WITH QUANTIZATION = ±1/2

10-BIT TRUNCATED TO 8-BIT RESULT

IDEAL 10-BIT CHARACTERISTIC

WITH QUANTIZATION = ±1/2

WHEN TRUNCATION IS USED,

ERROR FROM IDEAL 8-BIT = 3/8 LSB

DUE TO NON-IDEAL QUANTIZATION.

INPUT VOLTAGE

1/2

2 1/2

4 1/2

6 1/2

8 1/2

1 1/2

3 1/2

5 1/2

7 1/2

9 1/2

REPRESENTED AS 10-BIT

INPUT VOLTAGE

1/2

1 1/2

2 1/2

REPRESENTED AS 8-BIT

Figure 3-3. 8-Bit Truncation Mode Error

3.3.6 Monotonicity

The conversion process is monotonic and has no missing codes.

MC68HC908MR32 • MC68HC908MR16 Data Sheet, Rev. 6.1

Freescale Semiconductor

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.

Freescale Semiconductor MC68HC908MR16, MC68HC908MR32 manual Monotonicity, Bit Truncation Mode Error

Models: MC68HC908MR16 MC68HC908MR32