Watchdog timer special function register and example software design

　　(1) Watchdog timer control register WTCON

　　The watchdog timer control register WTCON is shown in Table 1. WTCON can enable the watchdog timer to select the clock signal from 4 different clock sources, enable or disable interrupts, and enable or disable the watchdog timer reset signal input.

　　Table 1 Watchdog timer control register WTCON

　　The watchdog timer is used to recover normal operation from an error after power supply using S3C44B0X. If you do not want to restart the processor, then the watchdog timer is disabled; if you want to use the normal timing function provided by the watchdog timer, you need to use the interrupt and watchdog timer functions.

　　(2) Watchdog timer data register WTDAT

　　The watchdog timer data register WTDAT is shown in Table 2. WTDAT is used to set the time limit value. After the watchdog timer is initialized, WTDAT cannot be automatically loaded into the timer counter. Initialization uses 0x8000. After the first time limit occurs, the WTDAT value will be automatically loaded into WTCNT.

　　Table 2 Watchdog timer data register WTDAT

　　(3) Watchdog timer count register WTCNT

　　The watchdog timer count register WTCNT is shown in Table 3. WTCNT contains the current count value of the watchdog timer under normal operation, so before enabling, the watchdog timer count register needs to be set to an initial value of 0x8000.

　　Table 3 Watchdog timer count register WTCNT

　　2. Example software design

　　The software design of the watchdog in this example mainly includes the initialization of the watchdog, feeding the dog, etc. Through the following program, the user can intuitively see the process of the watchdog resetting the system. [page]

　　Function to turn on/off the LED light: