I-Tech YMBAO100, User Manual

Page: 39 / 51

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A. How to Use GPIO in Linux
# Take gpio1_0 as example, export value:1*32+0=32
# GPIO example 1: Output
echo 32 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio40/direction
echo 0 > /sys/class/gpio/gpio40/value
echo 1 > /sys/class/gpio/gpio40/value
# GPIO example 2: Input
echo 32 > /sys/class/gpio/export
echo in > /sys/class/gpio/gpio40/direction
cat /sys/class/gpio/gpio40/value
B. How to Use Watchdog in Linux
// create fd
int fd;
//open watchdog device
fd = open("/dev/watchdog", O_WRONLY);
//get watchdog support
ioctl(fd, WDIOC_GETSUPPORT, &ident);
//get watchdog status
ioctl(fd, WDIOC_GETSTATUS, &status);
//get watchdog timeout
ioctl(fd, WDIOC_GETTIMEOUT, &timeout_val);
//set watchdog timeout
ioctl(fd, WDIOC_SETTIMEOUT, &timeout_val);
//feed dog
ioctl(fd, WDIOC_KEEPALIVE, &dummy);