實際上還是僅僅備份些代碼，加些注釋，因為這本身就很容易，沒啥多說的。。。

先定義些東西
#define PORT_IIC PORTC
#define DDR_IIC DDRC
#define BIT_SCL 0
#define BIT_SDA 1
#define TW_START 0X08
#define TW_REP_START 0X10
#define TW_MT_SLA_ACK 0X18

下面切入正題

iic總線初始化

void iic_init(void)

{

TWSR=0;

TWBR=32;//這點要注意下，不要設的速度太高，否則

//proteus仿真可能讀不到數(shù)據

TWAR=0;

TWCR=(1<

PORT_IIC|=(1<

}

iic初始與終止位

unsigned char iic_start(void)

{

TWCR=(1<

while(!(TWCR&(1<

if ((TWSR & 0xF8) != TW_START&&(TWSR & 0xF8) != TW_REP_START)

{

return 0;

}

else

{

return 1;

}

}

void iic_stop(void)

{

TWCR=(1<

}

iic讀取

unsigned char iic_read(unsigned int ack)

{

char data;

if(ack==1)

{

TWCR=(1<

}

else

{

TWCR=(1<

}

while(!(TWCR&(1<

data=TWDR;

return data;

}

iic寫入

unsigned char iic_write(unsigned char data)

{

unsigned char ack=1;

TWDR=data;

TWCR=(1<

while(!(TWCR&(1<

if((TWSR&0XF8)!=TW_MT_SLA_ACK)//檢測應答位

{

ack=0;

}

else

{

ack=1;

}

return ack;

}

eeprom片選

static unsigned char cs ;

void eeprom24s_set_cs(unsigned char addr)

{

cs=addr;

}

eeprom讀取

unsigned char eeprom24s_read(unsigned int addr)

{

unsigned char data;

iic_start();

iic_write(cs<<1);

iic_write(addr>>8);

iic_write(addr);

iic_start();

iic_write((cs<<1)|0x01);

data=iic_read(0);

iic_stop();

delay_us(10);//延時很重要，否則proteus可能出錯

return data;

}

eeprom寫入

unsigned char eeprom24s_write(unsigned int addr,unsigned char data)

{

iic_start();

iic_write(cs<<1);

iic_write(addr>>8);

iic_write(addr);

iic_write(data);

iic_stop();

delay_ms(10);)//延時很重要，否則proteus可能出錯

}

測試用例

Code

測試截圖