at24c512.c

来自「i2c 总线 at512读写程序」· C语言 代码 · 共 125 行

void I2cStop(void)
{
    SDA=0;
    SCL=1;
    NOP;
    SDA=1;
    NOP;
    SCL=0;    
}
void I2cStart(void)
{
    SCL=1;
    SDA=1;
    NOP;
    SDA=0;
    NOP;
    SCL=0;
}
void I2cWriteByte(unsigned char wbyte)
{
    unsigned char i;
    for(i=0;i<8;i++)
    {
        wbyte<<=1;
        if(CY)SDA=1;
        else SDA=0;
        NOP;
        SCL=1;
        NOP;
        SCL=0;
    }
    SDA=1;
    NOP;
    SCL=1;
    while(SDA);
    SCL=0;
}
unsigned char I2cReadByte(void)
{
    unsigned char i,rbyte;
    for(i=8;i--;)
    {
        SCL=1;
        rbyte<<=1;
        if(SDA)rbyte++;
        SCL=0;
    }
    return rbyte;
}
void I2cAck(bit ACK)
{
    SDA=ACK;
    NOP;    
    SCL=1;
    NOP;    
    SCL=0;
    SDA=1;
}
void EepromByteWrite(unsigned int addr,unsigned char wdata)
{
    I2cStart();
    I2cWriteByte(0xa0);
    I2cWriteByte(*(char*)&addr);
    I2cWriteByte(*(1+(char*)&addr));
    I2cWriteByte(wdata);
    I2cStop();
    delay_ms(10);
}
unsigned char EepromByteRead(unsigned int addr)
{
    unsigned char i;
    I2cStart();
    I2cWriteByte(0xa0);    
    I2cWriteByte(*(char*)&addr);
    I2cWriteByte(*(1+(char*)&addr));

    I2cStart();
    I2cWriteByte(0xa1);
    i=I2cReadByte();
    I2cStop();
    return i;    
}
void delay_ms(unsigned char delaytimes)
{
    unsigned char dely;
    while(delaytimes--)
    {
        dely=154;
        for (;--dely;);
    }
}
unsigned char EepromSequentialWrite(unsigned int addr,unsigned char xdata * 
buf,unsigned char len)
{
    unsigned char i;
    I2cStart();
    I2cWriteByte(0xa0);    
    I2cWriteByte(*(char*)&addr);
    I2cWriteByte(*(1+(char*)&addr));
    for(i=0;i<len;i++)
    {
        I2cWriteByte(* buf++);    
    }
    I2cStop();
    return i;
}
unsigned char EepromSequentialRead(unsigned int addr,unsigned char xdata * 
buf,unsigned char len)
{
    unsigned char i;
    I2cStart();
    I2cWriteByte(0xa0);    
    I2cWriteByte(*(char*)&addr);
    I2cWriteByte(*(1+(char*)&addr));

    I2cStart();
    I2cWriteByte(0xa1);
    for(i=0;i<len;i++)
    {
        * buf++=I2cReadByte();
        I2cAck(i==(len-1));    
    }
    I2cStop();
    return i;
}