User`s manual

UC-8410/8416/8418 LX User’s Manual Programmer’s Guide
5-5
Buzzer
The device node is located at /dev/console. The UC-8410/8416/8418 supports Linux standard
buzzer control, with the UC-8410/8416/8418’s buzzer running at a fixed frequency of 100 Hz.
You must include <sys/kd.h>.
1. Function: KDMKTONE
ioctl(fd, KDMKTONE, unsigned int arg);
Description: The buzzer’s behavior is determined by the argument arg. The “high word” part
of arg gives the length of time the buzzer will sound, and the “low word” part gives the
frequency.
The buzzer’s on/off behavior is controlled by software. If you call the “ioctl” function, you
MUST set the frequency to 100 Hz. If you use a different frequency, the system could crash.
WDT (Watch Dog Timer)
1. Introduction
The WDT works like a watch dog 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
…..
….
User application running and enable user ack
….
….
3. The user API
The user application must use
include <moxadevic.h> , and link libmoxalib.a . A
makefile example is shown below:
all:
xscale-linux-gcc –o xxxx xxxx.c -lmoxalib
int swtd_open(void)
Description
If you would like to activate Watchdog for the AP, you must call this function.
Input
None
Output
The return value is file handle. If there is an error, it will return a negative value.
You can get the error using the function errno().