CHAPTER 3 CPU

■Mode Fetch

The CPU reads the mode data and reset vector from internal ROM following the cancellation of the reset.

●Mode data (address: FFFDH)

Set single-chip mode (00H) to the mode data.

●Reset vector (address: FFFEH (highest)/FFFFH (lowest))

Specify the address at which execution is to be started after the reset operation is completed. The CPU starts executing instructions from the specified address.

■State of Reset Waiting for Stabilization of Oscillation

The CPU performs a reset operation for a reset when power is turned on or an external reset in stop mode when the oscillation stabilization wait time specified with option settings has expired. In this case, if the external reset input is not cancelled, the CPU performs the reset operation following cancellation of the external reset.

When an external clock is used, oscillation stabilization wait time is applied, and thus input of an external clock is required at a reset.

The time-base timer generates oscillation stabilization wait time.

■Influence from a Reset of Contents in RAM

When reset conditions occur, the CPU stops handling the current instruction, then enters the reset state. The contents in RAM does not change even after a reset. However, if a reset occurs while 16-bit data is being written, the upper byte (only) is written; the lower byte may be unwritten. If a reset occurs immediately after, immediately before, or while data is written, the contents in the address to which data is written at that time is not guaranteed.

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Fujitsu F202RA, MB89202 manual Mode Fetch, State of Reset Waiting for Stabilization of Oscillation
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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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