将ASC码转为数值函数

uint8_t ASC_NUM(char *array)
{
    uint8_t len=strlen(array);
    uint32_t num = 0;
    uint8_t i = 0;
    for(i=0;i<len;i++)
    {
        if(array[i]>=48&&array[i]<58)//判断是否为数值
        {
            num = num*10 + array[i]-48;
        }else                       //返回无效值
        {
        num = NULL;
        break;
        }
    }
    return num;
}