Fault Protection

BANK X

DISABLE

BANK Y

DISABLE

BIT 7

BIT 6

BIT 5

BIT 4

BIT 3

BIT 2

BIT 1

BIT 0

Figure 12-27. PWM Disabling Decode Scheme

DISABLE

PWM PIN 1

DISABLE

PWM PIN 2

DISABLE PWM PIN 3

DISABLE

PWM PIN 4

DISABLE

PWM PIN 5

DISABLE

PWM PIN 6

12.6.1.1 Fault Pin Filter

Each fault pin incorporates a filter to assist in determining a genuine fault condition. After a fault pin has been logic low for one CPU cycle, a rising edge (logic high) will be synchronously sampled once per CPU cycle for two cycles. If both samples are detected logic high, the corresponding FPIN bit and FFLAG bit will be set. The FPIN bit will remain set until the corresponding fault pin is logic low and synchronously sampled once in the following CPU cycle.

12.6.1.2 Automatic Mode

In automatic mode, the PWM(s) are disabled immediately once a filtered fault condition is detected (logic high). The PWM(s) remain disabled until the filtered fault condition is cleared (logic low) and a new PWM cycle begins as shown in Figure 12-28. Clearing the corresponding FFLAGx event bit will not enable the PWMs in automatic mode.

The filtered fault pin’s logic state is reflected in the respective FPINx bit. Any write to this bit is overwritten by the pin state. The FFLAGx event bit is set with each rising edge of the respective fault pin after filtering has been applied. To clear the FFLAGx bit, the user must write a 1 to the corresponding FTACKx bit.

f the FINTx bit is set, a fault condition resulting in setting the corresponding FFLAG bit will also latch a CPU interrupt request. The interrupt request latch is not cleared until one of these actions occurs:

•The FFLAGx bit is cleared by writing a 1 to the corresponding FTACKx bit.

•The FINTx bit is cleared. This will not clear the FFLAGx bit.

•A reset automatically clears all four interrupt latches.

MC68HC908MR32 • MC68HC908MR16 Data Sheet, Rev. 6.1

Freescale Semiconductor

139

Page 138 Page 140
Page 139
Image 139
Freescale Semiconductor MC68HC908MR16, MC68HC908MR32 manual Fault Pin Filter, Automatic Mode
Page 138 Page 140

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.
Top Page Image Contents