单片机学习笔记.单总线one-wire协议（这里以普中开发板DS18B20为例）

硬件原理图： 

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 DS18B20数据图：

 

 

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首先根据原理图定义对应引脚：

sbit OneWire_DQ=P3^7;

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 one-wire时序图：

one-wire初始化：

初始化时序分析： 

unsigned char OneWire_Init(void)
{
	unsigned char AckBit;
	OneWire_DQ=1;
	OneWire_DQ=0;
  Delay500us();
	OneWire_DQ=1;
	Delay70us();
	AckBit=OneWire_DQ;
	Delay500us();
	return AckBit;
}

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one-wire读/写 1位：

one-wire读/写 1位 时序分析： 

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 写一个位：

//写一个位
void OneWire_SendBit(unsigned char Bit)
{
	OneWire_DQ=0;
	Delay14us();//10us
	OneWire_DQ=Bit;
	Delay54us();//50us
	OneWire_DQ=1;
}

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 接收一位： 

//接收一位
unsigned char OneWire_ReciveBit(void)
{
	unsigned char Bit;
	OneWire_DQ=0;
	Delay9us();//5us
	OneWire_DQ=1;
	Delay9us();//5us
	Bit=OneWire_DQ;
	Delay54us();//50us
	return Bit;
}

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  写入1个字节：

//写入一个字节
void OneWire_SendByte(unsigned char Byte)
{
	unsigned char i;
	for(i=0;i<8;i++)
	{
		OneWire_SendBit(Byte&(0x01<<i));
	}
}

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 发送1个字节： 

//发送1个字节
unsigned char OneWire_ReciveByte(void)
{
	unsigned char Byte=0x00;
	unsigned char i;
	for(i=0;i<8;i++)
	{
		if(OneWire_ReciveBit()){Byte|=(0x01<<i);}
	}
	return Byte;
}

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