I am interested to take advantage of the watchdog functionality of fit-pc2 (which is a great computer by the way

I am using gentoo with the 2.6.32 kernel, I have enabled CONFIG_SBC_FITPC2_WATCHDOG=y on the config file and installed the watchdog daemon. But the daemon take a lot of CPU, every 5 seconds (approximately) it take 100 % of my CPU.
Is it normal ? I think it's not...
Is there another way to take advantage of the watchdog functionality ?
I have thought of a cron job which would write on the /dev/watchdog each 30 s, with watchdog activated on the bios ... will it work ??
PS : sorry for my bad english