用430寫的IIC總線協議：24C02掉電記憶程序(數碼管顯示)

#define OP_READ 0xa1 // 器件地址以及讀取操作
#define OP_WRITE 0xa0 // 器件地址以及寫入操作
#define uchar unsigned char
#define uint unsigned int
#define SDA_OUT P1DIR|=BIT3
#define SDA_IN P1DIR&=~BIT3
#define SCL_OUT P1DIR|=BIT2
#define SCL_IN P1DIR&=~BIT2
#define SDA_H P1OUT|=BIT3
#define SDA_L P1OUT&=~BIT3
#define SCL_H P1OUT|=BIT2
#define SCL_L P1OUT&=~BIT2
#define wei_h P5OUT|= BIT5
#define wei_l P5OUT&= ~BIT5
#define duan_l P6OUT &= ~BIT6
#define duan_h P6OUT |= BIT6
//數碼管7位段碼：0--f
uchar table[16] = {0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,
0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71};
//記錄顯示位數的全局變量
uchar miao;
uchar write;
//8M晶振時大約20us延時程序
void delayus(uint z)
{
uint i,j;
for(i = 0;i<20;i++)
for(j=0;j {;;};
}
// 開始位
void start()
{
SDA_OUT;
SCL_OUT;
SDA_H;
SCL_H;
delayus(1); //20
SDA_L;
delayus(2);//40
SCL_L;
}
// 停止位
void stop()
{
SDA_OUT;
SCL_OUT;
SDA_L;

delayus(2);//20
SCL_H;
delayus(2);
SDA_H;
}
// 從AT24Cxx移入數據到MCU
uchar shin()
{
uchar i,read_data;
SDA_OUT;
SCL_OUT;
for(i = 0; i < 8; i++)
{
SDA_H;
delayus(1);
SCL_H;
SDA_IN;
read_data <<= 1;
if(P1IN&BIT3)
read_data|=0x01;
SDA_OUT;
SCL_L;
}
return(read_data);
}
// 從MCU移出數據到AT24Cxx
uchar shout(uint write_data)
{
uchar i;
uchar ack_bit;
SDA_OUT;
SCL_OUT;
for(i = 0; i < 8; i++) // 循環移入8個位
{
if(write_data&0x80)
SDA_H;
else
SDA_L;
delayus(2);//2
SCL_H;
delayus(2);//2
SCL_L;
delayus(2);//2
write_data <<= 1;
}

SDA_H; // 讀取應答
delayus(2);
SCL_H; //注意拉高
delayus(2);
SDA_IN;
if(P1IN&BIT3)
ack_bit=1;
else ack_bit=0;
SCL_L;
return ack_bit; // 返回AT24Cxx應答位
}
// 在指定地址addr處寫入數據write_data
void write_byte(uchar addr, uchar write_data)
{
SDA_OUT;
SCL_OUT;
SDA_H;
SCL_H;
start();
shout(OP_WRITE);
shout(addr);
shout(write_data);
stop();
delayus(1000);// 寫入周期
}
// 在當前地址讀取
uint read_current()
{
uint read_data;
start();
shout(OP_READ);
read_data = shin();
stop();
return read_data;
}

// 在指定地址讀取
uchar read_random(uint random_addr)
{
SDA_IN;
SCL_OUT;
SDA_H;
SCL_H;
start();
shout(OP_WRITE);
shout(random_addr);
return(read_current());
}

void display(uchar dat)
{
P4OUT = table[dat];//輸出段選信號
duan_h;
duan_l;
P4OUT = 0x00; //設置P4，P5的輸出初值
wei_h;
wei_l;
}

void Clock(void)
{
miao++;
if(miao==10)
miao=0;
}

int main( void )
{
/*下面六行程序關閉所有的IO口*/
P1DIR = 0XFF;P1OUT = 0XFF;
P2DIR = 0XFF;P2OUT = 0XFF;
P3DIR = 0XFF;P3OUT = 0XFF;
P4DIR = 0XFF;P4OUT = 0XFF;
P5DIR = 0XFF;P5OUT = 0XFF;
P6DIR = 0XFF;P6OUT = 0XFF;


SDA_OUT;
SCL_OUT;
SDA_H;
SCL_H;


WDTCTL = WDTPW + WDTHOLD;
CCR0 = 32768 - 1;//設置定時器A的中斷時間為1S
TACTL = TASSEL_1 + MC_1; //計數時鐘ACLK, 增計數模式
CCTL0 |= CCIE; //使能CCR0比較中斷
_EINT();//打開全局中斷


miao=read_random(3) ;//從地址2中讀出以前保存的數據
if(miao>9) miao=0; //防止首次讀出錯誤數據

while(1)
{
display(miao);
if(write==1)
{
write=0;
write_byte(3,miao);
}

LPM3;//進入LPM3低功耗模式

}
}

/*******************************************
函數名稱：TimerA_ISR
功 能：定時器A的中斷服務函數
********************************************/
#pragmavector=TIMERA0_VECTOR
__interrupt void TimerA_ISR(void)
{
Clock();
write=1;
LPM3_EXIT;
}