CHAPTER 3 CPU

3.7.3Stop Mode

This section describes the stop mode.

■Operations Relating to Stop Mode

●Transition to stop mode

In stop mode, the oscillation frequency is stopped. Most functions stop storing data in the registers and RAM used immediately before transition to stop mode.

The clock circuit stops oscillating, the peripheral functions and CPU stop operating, but the external interrupt circuit continues to operate.

Writing "1" to the stop bit in the standby control register (STBC: STP) causes a transition to stop mode. At

that time, if the pin state setting bit (STBC: SPL) is "0", the states of the external pins are maintained. If the pin state setting bit is "1", the states of the external pins are set to Hi-Z (the states of pins for which a pull- up resistor is specified in the pull-up setting resistor are set to level "H").

An attempt to write "1" into the STP bit while an interrupt request is being generated fails, transition to stop mode cannot made, and instructions are processed continuously. (Even after the interrupt is processed completely, transition to stop mode is not made.)

For a transition to stop mode, prohibit the time-base timer interrupt request output (TBTC: TBIE = 0) when necessary.

●Cancellation of stop mode

Stop mode is cancelled by a reset or external interrupt.

When a reset occurs in stop mode, the reset operation is performed after oscillation stabilization wait time. pin states are initialized by the reset operation.

When an interrupt request with an interrupt level higher than 11B is generated in an external interrupt circuit in stop mode, stop mode is cancelled regardless of the CPU interrupt enable flag (CCR: I) or interrupt level bits (CCR: IL1 and IL0).

When stop mode is cancelled and oscillation stabilization wait time has expired, a normal interrupt operation is performed. Then, if interrupts are acceptable, interrupt processing is performed. Otherwise, an instruction following the instruction immediately before transition to stop mode is managed.

When an external interrupt cancels stop mode, part of the peripheral functions are restarted with data stored before the beginning of sleep mode. Therefore, the initial interval of the interval timer and other similar settings are rendered unknown. The peripheral functions must be initialized after returning from stop mode.

Note:

Among interrupts, only an interrupt request from the external interrupt circuit cancels the stop mode.

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Fujitsu F202RA, MB89202 manual Stop Mode, Transition to stop mode
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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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