CHAPTER 11 EXTERNAL INTERRUPT CIRCUIT 2 (LEVEL)

11.5Interrupt of External Interrupt Circuit 2

An "L" level input signal input to one of the external interrupt pins triggers external interrupt circuit 2 to generate an interrupt.

■Interrupt during the Operation of External Interrupt Circuit 2

When an "L" level signal is input to one of the external interrupt pins for which interrupt inputs are enabled, the external interrupt request flag bit (EIF2:IF20) is set to "1" and external interrupt circuit 2 generates and issues an interrupt request (IRQA) to the CPU. Write "0" for the IF20 bit within the interrupt processing routine, thus clearing the interrupt request.

When the external interrupt request flag bit (IF20) is set to "1", external interrupt circuit 2 generates the interrupt request, even if external interrupt inputs to the pin are set to disabled by the bit corresponding to the pin among the interrupt enable bits (IE20 to IE27) of the external interrupt 2 control register (EIE2), until the IF20 bit is cleared. Therefore, the IF20 bit must always be cleared.

If the "L" level input to the external interrupt pin continues as it is, even if the IF20 bit is cleared with external interrupt inputs to the pin remaining enabled, the IF20 bit is immediately set to "1" again. Disable external interrupt inputs to the pin or remove the cause of the external interrupt as required.

Notes:

•When enabling interrupts to the CPU following a release from the reset state, clear the IF20 bit in advance.

•"L" level inputs to external interrupt pins (INT20 to INT27) trigger external interrupt circuit 2 to generate the same interrupt request (IRQA). Thus, when an external interrupt input is detected, it is necessary to identify the pin at which the input occurs by reading the port 0 data register (PDR0) before the input changes to "H" level.

Only external interrupt circuits 1 and 2 can execute a release from the stop mode by an interrupt.

■Register Associated with Interrupt Generation by External Interrupt Circuit 2 and Vector Table

Table 11.5-1 Register Associated with Interrupt Generation by External Interrupt Circuit 2 and Vector Table

 

Interrupt level setting register

Vector table address

Interrupt designation

 

 

 

 

 

Register

Bit for setting level

Upper

Lower

 

 

 

 

 

 

 

IRQA

ILR3 (007DH)

LA1 (bit5)

LA0 (bit4)

FFE6H

FFE7H

 

 

 

 

 

 

For interrupt operation, see Section "3.4.2 Steps in the Interrupt Operation ".

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Fujitsu F202RA, MB89202 manual ILR3 007DH LA1 bit5 LA0 bit4
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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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