Stack Operation at Interrupt Processing, Xxh, E0H

CHAPTER 3 CPU

3.4.5Stack Operation at Interrupt Processing

This section describes how values in registers are saved and restored at interrupt processing.

■Stack Operation at the Beginning of Interrupt Processing

After accepting an interrupt, the CPU automatically saves the values in the program counter (PC) and program status (PS) in the stack.

Figure 3.4-5shows the stack operation at the beginning of interrupt processing.

Figure 3.4-5 Stack Operation at the Beginning of Interrupt Processing

Immediately before interruption

Immediately after interruption

Address Memory

PS	0870H		027CH
PS	0870H		027DH
			027DH
PC	E000H		027EH
PC	E000H		027FH
			027FH
	SP	0280H	0280H
	SP	0280H	0280H
			0281H
			0281H

XXH

SP		027CH	027CH
SP		027CH	027CH
			027DH
			027EH
PS	0870H		027EH
PS	0870H		027FH
			027FH
PC	E000H		0280H
PC	E000H		0281H
			0281H

08H

70H

E0H

00H

XXH

■Stack Operation at the End of Interrupt Processing

When the return instruction (RETI) is executed at the end of interrupt processing, the values in the program status (PS) and the program counter (PC) are restored from the stack in that order (which is opposite to that at the beginning of interrupt processing). This operation restores the values in the PS and PC to those values used before interruption.

Note:

Values in the accumulator (A) and temporary accumulator (T) are not automatically saved in the stack. Therefore, save and restore the values using the PUSHW and POPW instructions.

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.

Fujitsu F202RA, MB89202 manual Stack Operation at Interrupt Processing, Xxh, E0H

Models: F202RA MB89202