I/O Registers

 

Table 17-2. Mode, Edge, and Level Selection

 

 

 

 

MSxB:MSxA

ELSxB:ELSxA

Mode

Configuration

 

 

 

 

X0

00

Output preset

Pin under port control; initialize timer output level high

X1

00

Pin under port control; initialize timer output level low

 

 

 

 

 

00

01

 

Capture on rising edge only

00

10

Input capture

Capture on falling edge only

00

11

 

Capture on rising or falling edge

 

 

 

 

01

00

 

Softare compare only

01

01

Output compare

Toggle output on compare

01

10

or PWM

Clear output on compare

01

11

 

Set output on compare

 

 

 

 

1X

01

Buffered output

Toggle output on compare

1X

10

compare

Clear output on compare

or buffered

1X

11

Set output on compare

PWM

 

 

 

 

NOTE

When TOVx is set, a TIMB counter overflow takes precedence over a channel x output compare if both occur at the same time.

CHxMAX — Channel x Maximum Duty Cycle Bit

When the TOVx is 1 and clear output on compare is selected, setting the CHxMAX bit forces the duty cycle of buffered and unbuffered PWM signals to 100 percent. As Figure 17-9shows, CHxMAX bit takes effect in the cycle after it is set or cleared. The output stays at 100 percent duty cycle level until the cycle after CHxMAX is cleared.

OVERFLOW

OVERFLOW

OVERFLOW

OVERFLOW

OVERFLOW

PERIOD

PTEx/TCHx

OUTPUT

OUTPUT

OUTPUT

OUTPUT

COMPARE

COMPARE

COMPARE

COMPARE

CHxMAX

TOVx

Figure 17-9. CHxMAX Latency

MC68HC908MR32 • MC68HC908MR16 Data Sheet, Rev. 6.1

Freescale Semiconductor

249

Page 248 Page 250
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Freescale Semiconductor MC68HC908MR16, MC68HC908MR32 manual Pwm
Page 248 Page 250

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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