CHAPTER 3 CPU

3.5Reset

There are four sources of reset:

•External reset

•Software reset

•Watchdog reset

•Power-on reset

Oscillation stabilization wait time is not applied in some operating modes when a reset occurs or in some option settings.

■Reset Sources

Table 3.5-1 Reset Sources

Reset source

Reset condition

 

 

External reset

The external reset pin is "L" level.

 

 

Software reset

"0" is written into the software reset bit in the standby control register (STBC:

RST).

 

 

 

Watchdog reset

The watchdog timer overflows.

 

 

Power-on reset

Power is turned on.

 

 

●External reset

External reset occurs when "L" level is input to the external reset pin (RST). When the reset pin becomes "H" level, the external reset is cancelled.

For external reset when power is turned on or in stop mode, the reset operation is performed after oscillation stabilization wait time is up or the external reset is cancelled.

The external reset pin functions as the reset output pin in accordance with option settings.

●Software reset

Software reset generates a 4-instruction cycle reset by writing "0" into the software reset bit in the standby control register (STBC: RST). Software reset does not wait until oscillation stabilization wait time has expired.

●Watchdog reset

Watchdog reset generates a 4-instruction cycle reset when no data is written into the watchdog control register (WDTC) within a specified time after the watchdog timer is activated. Watchdog reset does not wait until oscillation stabilization wait time is up.

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Fujitsu F202RA, MB89202 manual Reset Sources
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F202RA, MB89202 specifications

The Fujitsu MB89202 and F202RA microcontrollers are part of the 16-bit microcontroller family, renowned for their robust performance and versatility in a variety of embedded system applications. These devices are tailored for high-efficiency operation across diverse industries, including automotive, consumer electronics, and industrial automation.

One of the main features of the MB89202 is its powerful CPU core, which operates at a clock speed of up to 20 MHz. This enables the microcontroller to perform complex calculations and consumer-grade applications seamlessly. The architecture is designed to handle multiple tasks effectively, making it suitable for real-time operations.

Memory capacity is a vital characteristic of the MB89202, featuring on-chip RAM and ROM configurations. The microcontroller can accommodate different memory variants, providing developers with flexibility in memory allocation based on their application requirements. This adaptability facilitates applications ranging from simple control systems to complex data processing tasks.

The F202RA variant extends the capabilities of the MB89202 by integrating advanced peripheral functions. It includes built-in timers, A/D converters, and serial communication interfaces, which are essential for interfacing with other hardware components or sensors. The availability of these peripherals reduces the need for additional external circuits, thus contributing to a more compact and cost-effective design.

In terms of power management, the MB89202 series employs advanced power-saving technologies. The microcontroller offers various low-power modes, enabling devices to conserve energy during idle times, making it highly suitable for battery-operated applications. This characteristic not only enhances the efficiency of devices but also extends their operational lifespan.

Moreover, the Fujitsu MB89202 series incorporates robust protection features, including watchdog timers and failure detection mechanisms. These safety features ensure reliable operation in critical systems, making them a preferred choice in applications where failure is not an option.

The MB89202 and F202RA microcontrollers also support a range of development tools and environments, including integrated development environments (IDEs) and software libraries, which facilitate rapid application development. With these tools, developers can efficiently prototype, debug, and optimize their applications.

In summary, the Fujitsu MB89202 and F202RA microcontrollers stand out with their efficient performance, extensive memory options, integrated peripherals, and power-saving capabilities, making them ideal for a wide array of embedded applications. Their reliability and robustness further enhance their attractiveness for designers seeking advanced microcontroller solutions.
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