Moxa DA-662A-I-8-LX [53/63] Buzzer

DA-662A Series Software Programmer's Guide

5-6

RTC (Real-time Clock)

The device node is located at /dev/rtc. DA-662A series supports Linux standard simple RTC control. You must

include <linux/rtc.h>.

1. Function: RTC_RD_TIME

int ioctl(fd, RTC_RD_TIME, struct rtc_time *time);

Description: read time information from RTC. It will return the value on argument 3.

2. Function: RTC_SET_TIME

int ioctl(fd, RTC_SET_TIME, struct rtc_time *time);

Description: set RTC time. Argument 3 will be passed to RTC.

Buzzer

The DA-662A series supports buzzer control running at a fixed frequency of 100 Hz. The buzzer‘s on/off

behavior is controlled by software. You may write a shell script to control it. The following sample shell script

is provided for reference.

Example:

#! /bin/sh

cd /sys/class/gpio

echo 10 > export

cd /sys/class/gpio/gpio10

echo out > direction

# echo 1 > value means to turn on the buzzer

echo 1 > value

# echo 0 > value means to turn off the buzzer

echo 0 > value

WDT (Watchdog Timer)

1. Introduction

The WDT works like a watchdog function. You can enable it or disable it. When the user enables WDT but the

application does not acknowledge it, the system will reboot. You can set the ack time from a minimum of 50

msec to a maximum of 60 seconds.

2. How the WDT works

The sWatchDog is enabled when the system boots up. The kernel will auto ack it. The user application can

also enable ack. When the user does not ack, it will let the system reboot.

Kernel boot

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User application running and enable user ack

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