用C语言写一个看门狗程序测试

用STC的MCU的IO方式控制74HC595驱动8位数码管。

用户可以修改宏来选择时钟频率.

显示效果为: 显示秒计数, 5秒后不喂狗, 等复位.

#define MAIN_Fosc 22118400L //定义主时钟

#include "STC15Fxxxx.H"

#define DIS_DOT 0x20

#define DIS_BLACK 0x10

#define DIS_ 0x11

#define Timer0_Reload (65536UL -(MAIN_Fosc / 1000)) //Timer 0 中断频率, 1000次/秒

u8 code t_display[]={ //标准字库

// 0 1 2 3 4 5 6 7 8 9 A B C D E F

0x3F,0x06,0x5B,0x4F,0x66,0x6D,0x7D,0x07,0x7F,0x6F,0x77,0x7C,0x39,0x5E,0x79,0x71,

//black - H J K L N o P U t G Q r M y

0x00,0x40,0x76,0x1E,0x70,0x38,0x37,0x5C,0x73,0x3E,0x78,0x3d,0x67,0x50,0x37,0x6e,

0xBF,0x86,0xDB,0xCF,0xE6,0xED,0xFD,0x87,0xFF,0xEF,0x46}; //0. 1. 2. 3. 4. 5. 6. 7. 8. 9. -1

u8 code T_COM[]={0x01,0x02,0x04,0x08,0x10,0x20,0x40,0x80}; //位码

sbit P_HC595_SER = P4^0; //pin 14 SER data input

sbit P_HC595_RCLK = P5^4; //pin 12 RCLk store (latch) clock

sbit P_HC595_SRCLK = P4^3; //pin 11 SRCLK Shift data clock

u8 LED8[8]; //显示缓冲

u8 display_index; //显示位索引

u16 ms_cnt;

u8 tes_cnt; //测试用的计数变量

void delay_ms(u8 ms);

void DisplayScan(void);

void main(void)

{

u8 i;

P0M1 = 0; P0M0 = 0; //设置为准双向口

P1M1 = 0; P1M0 = 0; //设置为准双向口

P2M1 = 0; P2M0 = 0; //设置为准双向口

P3M1 = 0; P3M0 = 0; //设置为准双向口

P4M1 = 0; P4M0 = 0; //设置为准双向口

P5M1 = 0; P5M0 = 0; //设置为准双向口

P6M1 = 0; P6M0 = 0; //设置为准双向口

P7M1 = 0; P7M0 = 0; //设置为准双向口

display_index = 0;

for(i=0; i<8; i++) LED8[i] = DIS_BLACK; //全部消隐

tes_cnt = 0;

ms_cnt = 0;

LED8[7] = ms_cnt;

while(1)

{

delay_ms(1); //延时1ms

DisplayScan();

if(tes_cnt <= 5) //5秒后不喂狗, 将复位,

WDT_CONTR = (D_EN_WDT + D_CLR_WDT + D_WDT_SCALE_16); // 喂狗

if(++ms_cnt >= 1000)

{

ms_cnt = 0;

tes_cnt++;

LED8[7] = tes_cnt;

}

}

}

void delay_ms(u8 ms)

{

u16 i;

do{

i = MAIN_Fosc / 13000;

while(--i) ; //14T per loop

}while(--ms);

}

void Send_595(u8 dat)

{

u8 i;

for(i=0; i<8; i++)

{

dat <<= 1;

P_HC595_SER = CY;

P_HC595_SRCLK = 1;

P_HC595_SRCLK = 0;

}

}

void DisplayScan(void)

{

Send_595(~T_COM[display_index]); //输出位码

Send_595(t_display[LED8[display_index]]); //输出段码

P_HC595_RCLK = 1;

P_HC595_RCLK = 0; //锁存输出数据

if(++display_index >= 8) display_index = 0; //8位结束回0

}