Output Control

PWM VALUE REG. 1 = 1

PWM VALUE REG. 2 = 2

IS1 POSITIVE

IS1 POSITIVE

IS1 NEGATIVE

 

IS1 NEGATIVE

 

 

PWM = 1

 

PWM = 1

 

PWM = 2

 

PWM = 2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PWM1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PWM2

Figure 12-20. Top/Bottom Correction for PWMs 1 and 2

12.5.4 Output Polarity

The output polarity of the PWMs is determined by two options: TOPNEG and BOTNEG. The top polarity option, TOPNEG, controls the polarity of PWMs 1, 3, and 5. The bottom polarity option, BOTNEG, controls the polarity of PWMs 2, 4, and 6. Positive polarity means that when the PWM is active, the PWM output is high. Conversely, negative polarity means that when the PWM is active, PWM output is low. See Figure 12-21.

NOTE

Both bits are found in the CONFIG register, which is a write-once register. This reduces the chances of the software inadvertently changing the polarity of the PWM signals and possibly damaging the motor drive hardware.

MC68HC908MR32 • MC68HC908MR16 Data Sheet, Rev. 6.1

Freescale Semiconductor

133

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Freescale Semiconductor MC68HC908MR16, MC68HC908MR32 manual Output Polarity, Top/Bottom Correction for PWMs 1
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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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