从0-99数码管显示，用EEPROM掉电保存数据，但是程序正确，为什么掉电数据不能保存 -

标题: 从0-99数码管显示，用EEPROM掉电保存数据，但是程序正确，为什么掉电数据不能保存 [打印本页]

作者: 陌路狂花 时间: 2017-11-14 22:17
标题: 从0-99数码管显示，用EEPROM掉电保存数据，但是程序正确，为什么掉电数据不能保存
# include <reg52.h>
# define uchar unsigned char
# define uint unsigned int
sbit scl = P2^1;
sbit sda = P2^0;
sbit P_HC595_SER = P2^7; //pin 14 SER data input
sbit P_HC595_RCLK  = P2^5; //pin 12 RCLk store (latch) clock
sbit P_HC595_SRCLK = P2^6; //pin 11 SRCLK Shift data clock

char code t_display[]={
//    0 1 2 3 4 5 6 7 8 9  //
0x3F,0x06,0x5B,0x4F,0x66,0x6D,0x7D,0x07,0x7F,0x6F, 0};

void init();
void start();
void stop();
void respons();
void write_byte(uchar);
uchar read_byte();
void delay();
//void delay1(uint);
void write_add(uchar, uchar);
uchar read_add(uchar);
void init1();
void we();
void dage(uchar, uchar);
void Send_595(uchar);

uchar shu, shi, ge, write, aa;

void main()
{
init();
//delay1(100);
shu = read_add(2);
init1();
dage(11, 11);
while(1)
{
we();
dage(shi, ge);
if(write == 1)
{
write = 0;
write_add(2, shu);

}
}

}

void init()
{
sda = 1;
delay();
scl = 1;
delay();
}

void start()
{
sda = 1;
delay();
scl = 1;
delay();
sda = 0;
delay();
}

void stop()
{
sda = 0;
delay();
scl = 1;
delay();
sda = 1;
delay();
}
void respons()
{
uchar i;
scl = 1;
delay();
while((sda == 1) && (i<250))
i++;
scl = 0;
delay();
}

void write_byte(uchar date)
{
uchar i, temp;
scl = 0;
delay();
temp = date;
for(i=0; i<8; i++)
{
temp = temp << 1;
sda = CY;
delay();
scl= 1;
delay();
scl =0;
   delay();
}
sda = 1;
delay();
}
uchar read_byte()
{
uchar i, k;
scl = 0;
delay();
sda = 1;
delay();
for(i=0; i<8; ++i)
{
scl = 1;
delay();
k = (k<<1)|sda;
scl = 0;
delay();
}
return k;
}

void delay()
{; ;}

/*void delay1(uint z)
{
uchar x, y;
for(x=z; x>0; x--)
   for(y=110; y>0; y--);
}*/

void write_add(uchar address, uchar date)
{
start();
write_byte(0xa0);
respons();
write_byte(address);
respons();
write_byte(date);
respons();
stop();
}

uchar read_add(uchar address)
{
uchar date;
start();
write_byte(0xa0);
respons();
write_byte(address);
respons();
start();
write_byte(0xa1);
respons();
date = read_byte();
stop();

return date;
}

void init1()
{
TMOD = 0x01;
TH0 = (65535-50000)/256;
TL0 = (65535-50000)%256;
EA = 1;
ET0 = 1;
TR0 = 1;

aa = 0;
shu = 0;
}

void timer0() interrupt 1
{
TH0 = (65535-50000)/256;
TL0 = (65535-50000)%256;
aa++;
}

void we()
{
if(aa == 20)
{
aa =0;
shu++;
if(shu == 100)
   shu = 0;
shi = shu/10;
   ge = shu%10;
write = 1;
}
}

void dage(uchar aa, uchar bb)
{
   Send_595(0xfe);
Send_595(t_display[aa]);
P_HC595_RCLK = 0;
P_HC595_RCLK = 1;
   Send_595(0xff);

Send_595(0xfd);
Send_595(t_display[bb]);
P_HC595_RCLK = 0;
P_HC595_RCLK = 1;
}

void Send_595(uchar dat)
{
uint i;
for(i=0; i<8; i++)
{
if(dat & 0x80) P_HC595_SER = 1;
else P_HC595_SER = 0;
P_HC595_SRCLK = 0;
P_HC595_SRCLK = 1;
dat = dat << 1;
}
}

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作者: wulin 时间: 2017-11-15 07:40
需要有外电源掉电检测电路，一旦检测到外电源掉电，立即保存相关数据，单片机电源要有足够大的电容容量维持写EEPROM的这段时间。

作者: wrdwrd 时间: 2017-11-15 09:10
掉电了怎么写进去？保证掉电前有足够的时间写完需要保存的内容，一般用一个单片机管教采样输入电源，单片机供电用大电容或电池。我们这边用时钟芯片DS1302的，每分钟把要保存的数据更新写进1302的ram，上电读就行了。

作者: 陌路狂花 时间: 2017-11-15 12:48
51单片机内部EEPROM实现掉电保存数据，不需要外部电路，这个程序该怎么改

作者: dhbt2021 时间: 2021-12-19 16:33
同样的问题，楼主问题解决没有？

作者: smart8888 时间: 2021-12-20 20:40
在电源端并一个大电容，电容前串一个正向二极管，用一个外中断接在二极管前面，当电源掉电时，电容中存的电能让单片机工作足够时间，进入中断写数据进EEPROM

欢迎光临 (http://www.51hei.com/bbs/)