CHAPTER 3 CPU

3.4.6Stack Area for Interrupt Processing

A stack area on RAM is used for interrupt processing. The value in the stack pointer (SP) is used as the start address of the stack area.

■Stack Area for Interrupt Processing

The stack area is used to save/restore the value in the program counter (PC) when executing the subroutine call instruction (CALL) or vector call instruction (CALLV) or temporarily save and restore values in registers or other storage with the PUSHW and POPW instruction.

•Locate the stack area on RAM together with the data area.

•It is recommended that the initial settings be specified such that the stack pointer (SP) indicates the highest address of RAM and that the data area be set up from the lowest address of RAM.

Figure 3.4-6is an example showing the stack area.

Figure 3.4-6 Stack Area for Interrupt Processing

Data area

Stack area

0000H

0080H

0280H

I/O

RAM

General- purpose register

Access prohibited

Value recommended for SP

(When the highest RAM address is 027FH)

ROM

FFFFH

Note:

For the stack area, interrupts, subroutine calls, or PUSHW instruction use addresses in descending order, and the return instructions (RETI and RET) or the POPW instruction releases addresses in the stack area in ascending order. When a lower address is used in the stack area due to multiple interrupts or subroutine calls, make arrangements so that the stack area does not overlap with the data area and general-purpose register area containing other data.

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Fujitsu MB89202, F202RA manual Stack Area for Interrupt Processing, 0000H 0080H 0280H, Ram, ROM Ffffh
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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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