MSP430 IIC通信

#include

#define OP_READ 0xa1 //器件地址读

#define OP_WRITE 0xa0 //器件地址写

#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

uchar table[16] = {0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71};

uchar miao;

uchar write;

int num;

void delayus(uint z)

{

uint i,j;

for(i = 0;i<20;i++)

for(j=0;j

{;;};

}

void start()

{

SDA_OUT;

SCL_OUT;

SDA_H;

SCL_H;

delayus(1);

SDA_L;

delayus(2);

SCL_L;

}

void stop()

{

SDA_OUT;

SCL_OUT;

SDA_L;

delayus(2);

SCL_H;

delayus(2);

SDA_H;

}

void Ack24()

{

SDA_OUT;

SCL_OUT;

SDA_H;

SCL_H;

delayus(2);

SDA_IN;

while(P1IN & BIT3)

SCL_L;

delayus(2);

}

//mcu读取数据

uchar read_byte()

{

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);

}

void write_byte(uint dat)

{

uchar i;

SDA_OUT;

SCL_OUT;

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

{

if(dat&0x80)

SDA_H;

else

SDA_L;

delayus(2);

SCL_H;

delayus(2);

SCL_L;

delayus(2);

dat <<= 1;

}

SCL_L;

delayus(2);

SDA_H;

delayus(2);

}

//向指定地址写数据

void write_dat(uchar addr,uchar write_data)

{

SDA_OUT;

SCL_OUT;

SDA_H;

SCL_H;

start();

write_byte(OP_WRITE);

Ack24();

write_byte(addr);

Ack24();

write_byte(write_data);

Ack24();

stop();

delayus(1000);

}

//从指定地址读数据

uchar read_random(uint random_addr)

{

uchar i;

SDA_OUT;

SCL_OUT;

SDA_H;

SCL_H;

start();

write_byte(OP_WRITE);

Ack24();

write_byte(random_addr);

Ack24();

start();

write_byte(OP_READ);

Ack24();

i = read_byte();

stop();

return i;

}

void display(uchar dat)

{

P4OUT = table[dat];

duan_h;

duan_l;

P4OUT = ~(1 << num);

wei_h;

wei_l;

}

void Clock(void)

{

miao++;

if(miao==10)

miao=0;

}

void main( void )

{

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_L;

// Stop watchdog timer to prevent time out reset

WDTCTL = WDTPW + WDTHOLD;

CCR0 = 32768 -1;

TACTL = TASSEL_1 + MC_1;

CCTL0 |= CCIE;

_EINT();

miao = read_random(3);

if(miao>9) miao=0;

while(1)

{

display(miao);

if(write==1)

{

write = 0;

write_dat(3,miao);

}

LPM3;

}

}

#pragma vector = TIMERA0_VECTOR

__interrupt void TimerA_ISR(void)

{

Clock();

write = 1;

LPM3_EXIT;

}