HL8548 watchdog reset timer

I am using HL8548 ( 5.5.26 FW) in my device. Sometimes it hangs, even it is in sleep mode. I cannot make a call (via ATD command), although I still ping AT OK with the module. So there is no way to check if the module hangs or doesn’t.
I am thinking of an external watchdog and using a GPIO of the module to clear the watchdog timer, but in the HL8548 there is no command can control a GPIO that generate and signal to clear the watchdog timer.
Do you have any suggestion for this case


how about using +KGPIO?