AVR单片机IIC实验

#include

#include

#define uchar unsigned char

#define uint unsigned int

//-----------------------------

uchar str1[]={"IIC TEST"};

//---------------------------

void delay(uint k) //延时函数

{

uint i,j;

for(i=0;i

for(j=0;j<1140;j++);

}

#include "1602.h" //1602库函数

//-------按键输入点设置-------

#define s1 (PIND&0x10) //变量值增加键

#define s2 (PIND&0x20) //变量值减少键

#define s3 (PIND&0x40) //存储键

#define s4 (PIND&0x80) //读取键

//-------------------

#define TWINT 7 //中断标志

#define TWEN 2 //中断时能

#define TWSTA 5 //启动状态位

#define TWSTO 4 //停止状态位

//-----TWI状态定义，MT主方式传送，MR主方式接受

#define START 0x08 //启动

#define RE_START 0x10 // 重新启动

#define MT_SLA_ACK 0x18 //主机应答

#define MT_SLA_NOACK 0x20 //主机非应答

#define MT_DATA_ACK 0x28 //主机数据传送后应答

#define MT_DATA_NOACK 0x30 //主机数据传送后非应答

#define MR_SLA_ACK 0x40 //从机应答

#define MR_SLA_NOACK 0x48 //从机非应答

#define MR_DATA_ACK 0x50 //从机数据应答

#define MR_DATA_NOACK 0x58 //从机数据非应答

//-------------------------

#define start() (TWCR=(1

#define stop() (TWCR=(1

#define wait() {while(!(TWCR&(1

#define testack() (TWSR&0xf8) //TWI状态检测，屏蔽预分频位

#define setack() (TWCR|(1

#define setnoack() (TWCR&=~(1

#define twi() (TWCR=(1

#define writebit(x) {TWDR=(x);TWCR=(1

//------I/0口设置------------

void portinit()

{

PORTA=0xff;

DDRA=0xff;

PORTB=0xff;

DDRB=0xff;

PORTC=0xff;

DDRC=0xff;

PORTD=0xff;

DDRD=0x00;

}

//-----------读数据函数----------

uchar iicread(uchar address)

{

uchar temp;

start();

wait();

if(testack()!=START) return 0;

writebit(0xa0);

wait();

if(testack()!=MT_SLA_ACK) return 0;

writebit(address);

wait();

if(testack()!=MT_DATA_ACK) return 0;

start();

wait();

if(testack()!=RE_START) return 0;

writebit(0xa1);

wait();

if(testack()!=MR_SLA_ACK) return 0;

twi();

wait();

if(testack()!=MR_DATA_NOACK) return 0;

temp=TWDR;

stop();

return temp;

}

//---------------写数据函数----------------

uchar iicwrite(uchar address,uchar data)

{

start();

wait();

if(testack()!=START) return 1;

writebit(0xa0);

wait();

if(testack()!=MT_SLA_ACK) return 1;

writebit(address);

wait();

if(testack()!=MT_DATA_ACK) return 1;

writebit(data);

wait();

if(testack()!=MT_DATA_ACK) return 1;

stop();

delay(10);

return 0;

}

void main()

{

uchar val=0; //数据值变量

portinit();

delay(200);

init();

delay(200);

display(2,0,str1);

delay(200);

while(1)

{

displayz(5,1,val/10+0x30);

displayz(6,1,val%10+0x30);

delay(10);

if(s1==0) //值增加键

{

delay(100); //软件延时100ms防止按键抖动

if(s1==0)

{

val++;

if(val>30)val=0;

}

}

if(s2==0) //值减少键

{

delay(100);

if(s2==0)

{

val--;

if(val<1)val=40;

}

}

if(s3==0) //值存储键

{

delay(100);

if(s3==0)

{

iicwrite(70,val);

}

}

if(s4==0) //值读取键

{

delay(100);

if(s4==0)

{

val=iicread(70);

}

}

}

}

//-------------------1602.h--------------------

//------------1602.h-------------

#define RS1 PORTB_Bit0=1

#define RS0 PORTB_Bit0=0

#define RW1 PORTB_Bit1=1

#define RW0 PORTB_Bit1=0

#define EN1 PORTB_Bit2=1

#define EN0 PORTB_Bit2=0

#define DATAPORT PORTA

#define busy 0x80

void wait()

{

uchar val;

DATAPORT=0xff;

RS0;

RW1;

__no_operation();

EN1;

__no_operation();

__no_operation();

DDRA=0x00;

val=PINA;

while(val&busy)val=PINA;

EN0;

DDRA=0xff;

}

void writecmd(uchar w)

{

wait();

RS0;

RW0;

__no_operation();

DATAPORT=w;

__no_operation();

EN1;

__no_operation();

__no_operation();

EN0;

}

void writedata(uchar data)

{

wait();

RS1;

RW0;

__no_operation();

DATAPORT=data;

__no_operation();

EN1;

__no_operation();

__no_operation();

EN0;

}

void delay_nms(uint k)

{

uint i,j;