CHAPTER 6 WATCHDOG TIMER

6.6Program Example for Watchdog Timer

Programming examples for the watchdog timer are provided below.

Programming Examples of Watchdog Timer

Processing specification

Activate the watchdog timer immediately after the program starts.

Clear the watchdog timer whenever the loop of the main program is run.

Ensure that the time necessary for running the main loop once, including interrupt handling, is shorter than the minimum time interval (approximately 335.5 ms: operating at 12.5 MHz) of the watchdog timer.

Coding example

WDTC

EQU

0009H

;

Address of watchdog control register

WDT_CLR EQU

00000101B

 

 

VECT

DSEG

ABS

;

[DATA SEGMENT]

 

ORG

0FFFEH

 

 

RST_V

DW

PROG

;

Setting reset vector

VECT

ENDS

 

 

 

;------------------------

Main program---------------------------------------------------------------------------------

 

 

CSEG

 

;

[CODE SEGMENT]

PROG

 

 

; Initialization routine upon reset

 

MOVW

SP,#0280H

;

Setting initial value of stack pointer (for interrupt)

 

:

 

 

 

 

Initializing interrupt or other peripheral functions

 

:

 

 

 

INIT

MOV

WDTC,#WDT_CLR

;

Activating watchdog timer

MAIN

MOV

WDTC,#WDT_CLR

;

Clearing watchdog timer

 

:

 

 

 

 

User processing (interrupt may occur in this processing.)

 

:

 

 

 

 

JMP

MAIN

;

Ensure that the time necessary for running the loop is

 

 

 

 

shorter than the minimum time interval of the watchdog

 

 

 

 

timer.

ENDS ;---------------------------------------------------------------------------------------------------------------------

END

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Fujitsu F202RA, MB89202 manual Program Example for Watchdog Timer

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.