Cortex_A9----WDT:看门狗

看门狗实验


t_watchdog = 1/(PCLK/(Prescaler value + 1)/Division_factor)
                    = 1/100000000Hz/(249+1)/128
                    = 1/3125  s         

 WTCON：
Prescaler value  [15:8]： Prescaler value.  The valid range is from 0 to (2^8– 1).    249
        WDT timer  [5] ： 1 = Enables WDT bit    //开启看门狗
        Clock select  [4:3]： 00 = 16          
                              01 = 32
                              10 = 64
                              11 = 128
        Reset enable/disable [0]; 1  enable

        WTCNT:  31250    10s

#include "exynos_4412.h"

int main()
{
    /* 1. 设置一级分频系数 */
    WDT.WTCON = WDT.WTCON & (~(0xff<<8)) | (249<<8);

    /* 2, 设置二级分频系数 */
    WDT.WTCON = WDT.WTCON & (~(0x3<<3)) | (0x3<<3); //1/100M/250/128 = 1/3125s

    /* 3. 设置减法计数器的值 */
    //WDT.WTDAT = 31250; //10s系统复位
    WDT.WTCNT = 31250; //31250 * 1/3125s = 10s

    /* 4. 开启看门狗的reset功能 */
    WDT.WTCON |= (0x1<<0);

    /* 5. 开启看门狗 */
    WDT.WTCON |= (0x1<<5);

    while (1)
    {
        WDT.WTCNT = 3000; //喂狗
    }

    return 0;
}